Energy Audit of Building Systems An Engineering Approach Second Edition Moncef Krarti
- 1. Energy Audit of Building Systems An Engineering Approach Second Edition Moncef Krarti pdf download https://ebookgate.com/product/energy-audit-of-building-systems- an-engineering-approach-second-edition-moncef-krarti/ Get Instant Ebook Downloads – Browse at https://ebookgate.com
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- 6. ENERGY AUDIT OF BUILDING SYSTEMS AN ENGINEERING APPROACH S E C O N D E D I T I O N
- 7. Mechanical Engineering Series Frank Kreith, Series Editor Computer Techniques in Vibration Edited by Clarence W. de Silva Distributed Generation: The Power Paradigm for the New Millennium Edited by Anne-Marie Borbely and Jan F. Kreider Elastic Waves in Composite Media and Structures: With Applications to Ultrasonic Nondestructive Evaluation Subhendu K. Datta and Arvind H. Shah Elastoplasticity Theory Vlado A. Lubarda Energy Audit of Building Systems: An Engineering Approach, Second Edition Moncef Krarti Energy Conversion Edited by D. Yogi Goswami and Frank Kreith Energy Management and Conservation Handbook Edited by Frank Kreith and D. Yogi Goswami The Finite Element Method Using MATLAB, Second Edition Young W. Kwon and Hyochoong Bang Fluid Power Circuits and Controls: Fundamentals and Applications John S. Cundiff Fundamentals of Environmental Discharge Modeling Lorin R. Davis Handbook of Energy Efficiency and Renewable Energy Edited by Frank Kreith and D. Yogi Goswami Heat Transfer in Single and Multiphase Systems Greg F. Naterer Heating and Cooling of Buildings: Design for Efficiency, Revised Second Edition Jan F. Kreider, Peter S. Curtiss, and Ari Rabl Intelligent Transportation Systems: Smart and Green Infrastructure Design, Second Edition Sumit Ghosh and Tony S. Lee Introduction to Biofuels David M. Mousdale Introduction to Precision Machine Design and Error Assessment Edited by Samir Mekid Introductory Finite Element Method Chandrakant S. Desai and Tribikram Kundu Machine Elements: Life and Design Boris M. Klebanov, David M. Barlam, and Frederic E. Nystrom Mathematical and Physical Modeling of Materials Processing Operations Olusegun Johnson Ilegbusi, Manabu Iguchi, and Walter E. Wahnsiedler Mechanics of Composite Materials Autar K. Kaw Mechanics of Fatigue Vladimir V. Bolotin Mechanism Design: Enumeration of Kinematic Structures According to Function Lung-Wen Tsai
- 8. Mechatronic Systems: Devices, Design, Control, Operation and Monitoring Edited by Clarence W. de Silva The MEMS Handbook, Second Edition (3 volumes) Edited by Mohamed Gad-el-Hak MEMS: Introduction and Fundamentals MEMS: Applications MEMS: Design and Fabrication Multiphase Flow Handbook Edited by Clayton T. Crowe Nanotechnology: Understanding Small Systems Ben Rogers, Sumita Pennathur, and Jesse Adams Nuclear Engineering Handbook Edited by Kenneth D. Kok Optomechatronics: Fusion of Optical and Mechatronic Engineering Hyungsuck Cho Practical Inverse Analysis in Engineering David M. Trujillo and Henry R. Busby Pressure Vessels: Design and Practice Somnath Chattopadhyay Principles of Solid Mechanics Rowland Richards, Jr. Thermodynamics for Engineers Kau-Fui Vincent Wong Vibration Damping, Control, and Design Edited by Clarence W. de Silva Vibration and Shock Handbook Edited by Clarence W. de Silva Viscoelastic Solids Roderic S. Lakes
- 10. ENERGY AUDIT OF BUILDING SYSTEMS AN ENGINEERING APPROACH Moncef Krarti S E C O N D E D I T I O N CRC Press is an imprint of the Taylor & Francis Group, an informa business Boca Raton London New York
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- 12. vii Contents Preface. .......................................................................................................................................xvii Author......................................................................................................................................... xix 1 Introduction to Energy Audit..................................................................................... 1-1 1.1 Introduction....................................................................................................................................1-1 1.2 Types of Energy Audits..................................................................................................................1-2 1.2.1 Walk-Through Audit........................................................................................................1-2 1.2.2 Utility Cost Analysis........................................................................................................1-2 1.2.3 Standard Energy Audit....................................................................................................1-2 1.2.4 Detailed Energy Audit.....................................................................................................1-3 1.3 General Procedure for a Detailed Energy Audit. .......................................................................1-3 1.3.1 Step 1: Building and Utility Data Analysis...................................................................1-4 1.3.2 Step 2: Walk-Through Survey.........................................................................................1-4 1.3.3 Step 3: Baseline for Building Energy Use......................................................................1-4 1.3.4 Step 4: Evaluation of Energy Savings Measures...........................................................1-4 1.4 Common Energy Conservation Measures.................................................................................1-5 1.4.1 Building Envelope.............................................................................................................1-5 1.4.2 Electrical Systems.............................................................................................................1-7 1.4.3 HVAC Systems..................................................................................................................1-8 1.4.4 Compressed Air Systems.................................................................................................1-9 1.4.5 Energy Management Controls........................................................................................1-9 1.4.6 Indoor Water Management.............................................................................................1-9 1.4.7 New Technologies...........................................................................................................1-10 1.5 Case Study......................................................................................................................................1-10 1.5.1 Step 1: Building and Utility Data Analysis.................................................................1-11 1.5.2 Step 2: On-Site Survey....................................................................................................1-13 1.5.3 Step 3: Energy Use Baseline Model..............................................................................1-14 1.5.4 Step 4: Evaluation of Energy Conservation Opportunities (ECOs).......................1-15 1.5.5 Step 5: Recommendations.............................................................................................1-17 1.6 Verification Methods of Energy Savings...................................................................................1-17 1.7 Summary........................................................................................................................................1-18 2 Energy Sources and Utility Rate Structures........................................................... 2-1 2.1 Introduction....................................................................................................................................2-1 2.2 Energy Resources............................................................................................................................2-1
- 13. viii Contents 2.2.1 Electricity...........................................................................................................................2-2 2.2.1.1 Overall Consumption and Price....................................................................2-2 2.2.1.2 Future of U.S. Electricity Generation. ...........................................................2-3 2.2.1.3 Utility Deregulation Impact.......................................................................... 2-4 2.2.2 Natural Gas........................................................................................................................2-5 2.2.3 Petroleum Products..........................................................................................................2-5 2.2.4 Coal.................................................................................................................................... 2-6 2.3 Electricity Rates..............................................................................................................................2-7 2.3.1 Common Features of Utility Rates................................................................................2-7 2.3.1.1 Billing Demand............................................................................................... 2-8 2.3.1.2 Power Factor Clause. ....................................................................................... 2-8 2.3.1.3 Ratchet Clause................................................................................................2-10 2.3.1.4 Fuel Cost Adjustment....................................................................................2-11 2.3.1.5 Service Level. ...................................................................................................2-12 2.3.2 Block Pricing Rates.........................................................................................................2-12 2.3.3 Seasonal Pricing Rates...................................................................................................2-14 2.3.4 Innovative Rates..............................................................................................................2-16 2.3.4.1 Time-of-Use (TOU) Rates............................................................................2-16 2.3.4.2 Real-Time-Pricing (RTP) Rates. ...................................................................2-16 2.3.4.3 The End-Use Rates.........................................................................................2-16 2.3.4.4 Specialty Rates................................................................................................2-17 2.3.4.5 Financial Incentive Rates..............................................................................2-17 2.3.4.6 Nonfirm Rates. ................................................................................................2-17 2.3.4.7 Energy Purchase Rates..................................................................................2-17 2.3.5 Real-Time-Pricing Rates................................................................................................2-17 2.3.5.1 Category 1: Base Bill and Incremental Energy Charge Rates. .................2-18 2.3.5.2 Category 2: Total Energy Charge Rates......................................................2-18 2.3.5.3 Category 3: Day-Type Rates..........................................................................2-18 2.3.5.4 Category 4: Index-Type Rates.......................................................................2-18 2.3.6 Case Study of RTP Rates................................................................................................2-18 2.4 Natural Gas Rates........................................................................................................................ 2-23 2.5 Utility Rates for Other Energy Sources.................................................................................... 2-25 2.6 Summary....................................................................................................................................... 2-25 3 Economic Analysis......................................................................................................... 3-1 3.1 Introduction....................................................................................................................................3-1 3.2 Basic Concepts................................................................................................................................3-1 3.2.1 Interest Rate.......................................................................................................................3-2 3.3 Inflation Rate.................................................................................................................................. 3-4 3.3.1 Tax Rate............................................................................................................................. 3-5 3.3.2 Cash Flows........................................................................................................................ 3-6 3.4 Compounding Factors...................................................................................................................3-7 3.4.1 Single Payment..................................................................................................................3-7 3.4.2 Uniform-Series Payment................................................................................................ 3-8 3.5 Economic Evaluation Methods among Alternatives............................................................... 3-9 3.5.1 Net Present Worth........................................................................................................... 3-9 3.5.2 Rate of Return.................................................................................................................3-10 3.5.3 Benefit–Cost Ratio..........................................................................................................3-10 3.5.4 Payback Period................................................................................................................3-10 3.5.5 Summary of Economic Analysis Methods.................................................................3-11
- 14. Contents ix 3.6 Life-Cycle Cost Analysis Method..............................................................................................3-13 3.7 General Procedure for an Economic Evaluation.....................................................................3-15 3.8 Financing Options........................................................................................................................3-16 3.8.1 Direct Purchasing...........................................................................................................3-16 3.8.2 Leasing..............................................................................................................................3-17 3.8.3 Performance Contracting..............................................................................................3-17 3.9 Summary........................................................................................................................................3-18 4 Energy Analysis Tools................................................................................................... 4-1 4.1 Introduction....................................................................................................................................4-1 4.2 Ratio-Based Methods.....................................................................................................................4-2 4.2.1 Introduction......................................................................................................................4-2 4.2.2 Types of Ratios..................................................................................................................4-3 4.2.3 Examples of Energy Ratios..............................................................................................4-3 4.3 Inverse Modeling Methods.......................................................................................................... 4-4 4.3.1 Steady-State Inverse Models........................................................................................... 4-4 4.3.1.1 ANAGRAM Method...................................................................................... 4-5 4.3.1.2 PRISM Method.................................................................................................4-7 4.3.2 Dynamic Models.............................................................................................................. 4-8 4.4 Forward Modeling Methods........................................................................................................ 4-9 4.4.1 Steady-State Methods...................................................................................................... 4-9 4.4.2 Degree-Day Methods...................................................................................................... 4-9 4.4.3 Bin Methods....................................................................................................................4-10 4.4.4 Dynamic Methods..........................................................................................................4-11 4.5 Summary........................................................................................................................................4-14 5 Electrical Systems........................................................................................................... 5-1 5.1 Introduction....................................................................................................................................5-1 5.2 Review of Basics..............................................................................................................................5-1 5.2.1 Alternating Current Systems..........................................................................................5-1 5.2.2 Power Factor Improvement............................................................................................ 5-4 5.3 Electrical Motors........................................................................................................................... 5-6 5.3.1 Introduction..................................................................................................................... 5-6 5.3.2 Overview of Electrical Motors....................................................................................... 5-6 5.3.3 Energy-Efficient Motors.................................................................................................. 5-8 5.3.3.1 General Description. ....................................................................................... 5-8 5.3.3.2 Adjustable Speed Drives (ASDs)................................................................... 5-8 5.3.3.3 Energy Savings Calculations........................................................................5-10 5.4 Lighting Systems...........................................................................................................................5-13 5.4.1 Introduction....................................................................................................................5-13 5.4.2 Energy-Efficient Lighting Systems...............................................................................5-14 5.4.2.1 High-Efficiency Fluorescent Lamps............................................................5-15 5.4.2.2 Compact Fluorescent Lamps........................................................................5-16 5.4.2.3 Compact Halogen Lamps.............................................................................5-16 5.4.2.4 Electronic Ballasts..........................................................................................5-16 5.4.3 Lighting Controls............................................................................................................5-17 5.4.3.1 Occupancy Sensors........................................................................................5-17 5.4.3.2 Light Dimming Systems. ...............................................................................5-18 5.4.3.3 Energy Savings from Daylighting Controls...............................................5-18
- 15. x Contents 5.5 Electrical Appliances. .................................................................................................................. 5-20 5.5.1 Office Equipment........................................................................................................... 5-20 5.5.2 Residential Appliances...................................................................................................5-21 5.6 Electrical Distribution Systems................................................................................................. 5-24 5.6.1 Introduction................................................................................................................... 5-24 5.6.2 Transformers.................................................................................................................. 5-25 5.6.3 Electrical Wires...............................................................................................................5-27 5.7 Power Quality................................................................................................................................5-31 5.7.1 Introduction....................................................................................................................5-31 5.7.2 Total Harmonic Distortion...........................................................................................5-31 5.8 Summary....................................................................................................................................... 5-34 6 Building Envelope.......................................................................................................... 6-1 6.1 Introduction....................................................................................................................................6-1 6.2 Basic Heat Transfer Concepts.......................................................................................................6-1 6.2.1 Heat Transfer from Walls and Roofs.............................................................................6-1 6.2.2 Infiltration Heat Loss/Gain............................................................................................ 6-3 6.2.3 Variable Base Degree-Days Method............................................................................. 6-9 6.3 Simplified Calculation Tools for Building Envelope Audit...................................................6-11 6.3.1 Estimation of the Energy Use Savings.........................................................................6-11 6.3.2 Estimation of the BLC for the Building......................................................................6-11 6.3.3 Estimation of the Degree Days.................................................................................... 6-12 6.3.4 Foundation Heat Transfer Calculations......................................................................6-16 6.3.5 Simplified Calculation Method for Building Foundation Heat Loss/Gain..........................................................................................................6-17 6.3.5.1 Calculation Example No. 1: Basement for a Residential Building.............................................................................................6-20 6.3.5.2 Calculation Example No. 2: Freezer Slab...................................................6-21 6.4 Selected Retrofits for Building Envelope................................................................................. 6-25 6.4.1 Insulation of Poorly Insulated Building Envelope Components........................... 6-25 6.4.2 Window Improvements................................................................................................ 6-26 6.4.3 Reduction of Air Infiltration........................................................................................ 6-27 6.5 Summary....................................................................................................................................... 6-29 7 Secondary HVAC Systems Retrofit. ........................................................................... 7-1 7.1 Introduction....................................................................................................................................7-1 7.2 Types of Secondary HVAC Systems. ............................................................................................7-1 7.3 Ventilation Systems........................................................................................................................7-3 7.3.1 Ventilation Air Intake......................................................................................................7-4 7.3.2 Air Filters...........................................................................................................................7-8 7.3.3 Air-Side Economizers......................................................................................................7-8 7.3.3.1 Temperature Economizer Cycle. ....................................................................7-8 7.3.3.2 Enthalpy Economizer Cycle...........................................................................7-9 7.4 Ventilation of Parking Garages....................................................................................................7-9 7.4.1 Existing Codes and Standards......................................................................................7-10 7.4.2 General Methodology for Estimating the Ventilation Requirements for Parking Garages..............................................................................................................7-11 7.4.2.1 Step 1. Collect the Following Data..............................................................7-11 7.4.2.2 Step 2................................................................................................................7-12 7.4.2.3 Step 3. ..............................................................................................................7-12
- 16. Contents xi 7.5 Indoor Temperature Controls....................................................................................................7-15 7.6 Upgrade of Fan Systems..............................................................................................................7-15 7.6.1 Introduction....................................................................................................................7-15 7.6.2 Basic Principles of Fan Operation................................................................................7-15 7.6.3 Duct Leakage...................................................................................................................7-20 7.6.4 Damper Leakage.............................................................................................................7-20 7.6.5 Size Adjustment..............................................................................................................7-21 7.7 Common HVAC Retrofit Measures...........................................................................................7-22 7.7.1 Reduction of Outdoor Air Volume..............................................................................7-22 7.7.2 Reset Hot or Cold Deck Temperatures........................................................................7-24 7.7.3 CV to VAV System Retrofit...........................................................................................7-25 7.8 Summary........................................................................................................................................7-26 8 Central Heating Systems.............................................................................................. 8-1 8.1 Introduction....................................................................................................................................8-1 8.2 Basic Combustion Principles........................................................................................................8-1 8.2.1 Fuel Types..........................................................................................................................8-1 8.2.2 Boiler Configurations and Components.......................................................................8-3 8.2.2.1 Boiler Types.......................................................................................................8-3 8.2.2.2 Firing Systems.................................................................................................. 8-4 8.2.3 Boiler Thermal Efficiency............................................................................................... 8-5 8.3 Boiler Efficiency Improvements...................................................................................................8-7 8.3.1 Existing Boiler Tune-Up................................................................................................. 8-9 8.3.2 High-Efficiency Boilers..................................................................................................8-11 8.3.3 Modular Boilers..............................................................................................................8-11 8.4 Summary........................................................................................................................................8-12 9 Cooling Equipment........................................................................................................ 9-1 9.1 Introduction....................................................................................................................................9-1 9.2 Basic Cooling Principles................................................................................................................9-1 9.3 Types of Cooling Systems..............................................................................................................9-5 9.3.1 Unitary AC Systems.........................................................................................................9-5 9.3.2 Packaged AC Units...........................................................................................................9-5 9.3.3 Heat Pumps. .......................................................................................................................9-5 9.3.4 Central Chillers................................................................................................................ 9-6 9.3.4.1 Electric Chillers............................................................................................... 9-6 9.3.4.2 Absorption Chillers........................................................................................ 9-6 9.3.4.3 Engine-Driven Chillers.................................................................................. 9-6 9.4 Water Distribution Systems..........................................................................................................9-7 9.4.1 Pumps.................................................................................................................................9-7 9.4.2 Pump and System Curves............................................................................................... 9-9 9.4.3 Analysis of Water Distribution Systems. .....................................................................9-10 9.5 District Cooling Systems.............................................................................................................9-12 9.6 Multichiller Systems.....................................................................................................................9-15 9.7 Energy Conservation Measures.................................................................................................9-15 9.7.1 Chiller Replacement.......................................................................................................9-17 9.7.2 Chiller Control Improvement.......................................................................................9-19 9.7.3 Alternative Cooling Systems.........................................................................................9-21 9.8 Summary........................................................................................................................................9-21
- 17. xii Contents 10 Energy Management Control Systems.................................................................... 10-1 10.1 Introduction..................................................................................................................................10-1 10.2 Basic Control Principles............................................................................................................. 10-2 10.2.1 Control Modes. ............................................................................................................... 10-2 10.2.2 Intelligent Control Systems..........................................................................................10-6 10.2.3 Types of Control Systems............................................................................................. 10-7 10.3 Energy Management Systems.................................................................................................... 10-8 10.3.1 Basic Components of an EMCS................................................................................... 10-8 10.3.2 Typical Functions of EMCS......................................................................................... 10-9 10.3.3 Design Considerations of an EMCS..........................................................................10-10 10.3.4 Communication Protocols..........................................................................................10-11 10.4 Control Applications................................................................................................................. 10-12 10.4.1 Duty Cycling Controls.................................................................................................10-14 10.4.2 Outdoor Air Intake Controls..................................................................................... 10-15 10.4.2.1 VAV Control Techniques for Economizer Systems................................10-17 10.4.2.2 VAV Control Techniques for Systems with a Dedicated Outside Air Duct.........................................................................................................10-19 10.4.2.3 Other VAV Control Techniques. ............................................................... 10-20 10.4.2.4 Comparative Analysis................................................................................ 10-21 10.4.3 Optimum Start Controls............................................................................................ 10-22 10.4.4 Cooling/Heating Central Plant Optimization........................................................ 10-24 10.4.4.1 Single Chiller Control Improvement....................................................... 10-24 10.4.4.2 Controls for Multiple Chillers................................................................... 10-25 10.4.4.3 Controls for Multiple Boilers. .................................................................... 10-26 10.5 Summary..................................................................................................................................... 10-26 11 Compressed Air Systems.............................................................................................11-1 11.1 Introduction..................................................................................................................................11-1 11.2 Review of Basic Concepts............................................................................................................11-1 11.2.1 Production of Compressed Air.....................................................................................11-1 11.2.1.1 Filters................................................................................................................11-5 11.2.1.2 Receiving Tanks.............................................................................................11-6 11.2.1.3 Dryers...............................................................................................................11-6 11.2.1.4 Intercoolers. .....................................................................................................11-7 11.2.2 Distribution of Compressed Air...................................................................................11-7 11.2.2.1 Flow Pressure Drop. .......................................................................................11-7 11.2.2.2 Air Leaks.........................................................................................................11-8 11.2.3 Utilization of Compressed Air.....................................................................................11-9 11.3 Common Energy Conservation Measures for Compressed Air Systems............................11-9 11.3.1 Reduction of Inlet Air Temperature..........................................................................11-10 11.3.2 Reduction of Discharge Pressure...............................................................................11-11 11.3.3 Repair of Air Leaks.......................................................................................................11-12 11.3.4 Other Energy Conservation Measures......................................................................11-13 11.4 Summary......................................................................................................................................11-13 12 Thermal Energy Storage Systems............................................................................. 12-1 12.1 Introduction..................................................................................................................................12-1 12.2 Types of TES Systems.................................................................................................................. 12-2 12.3 Principles of TES Systems..........................................................................................................12-4
- 18. Contents xiii 12.4 Charging/Discharging of TES systems.................................................................................... 12-5 12.5 TES Control Strategies................................................................................................................ 12-9 12.5.1 Full Storage..................................................................................................................... 12-9 12.5.2 Partial Storage................................................................................................................ 12-9 12.5.2.1 Chiller-Priority Control............................................................................... 12-9 12.5.2.2 Constant-Proportion Control....................................................................12-10 12.5.2.3 Storage-Priority Control.............................................................................12-10 12.5.2.4 Optimal Controls.........................................................................................12-10 12.5.3 Utility Rates...................................................................................................................12-11 12.5.3.1 TOU Rates.....................................................................................................12-11 12.5.3.2 RTP Rates......................................................................................................12-11 12.6 Measures for Reducing Operating Costs............................................................................... 12-12 12.6.1 Simplified Feasibility Analysis of TES Systems...................................................... 12-12 12.6.2 TES Control Improvement..........................................................................................12-14 12.6.2.1 Effect of Plant Size........................................................................................12-14 12.6.2.2 Effect of the Cooling Load Profile.............................................................12-15 12.7 Summary......................................................................................................................................12-16 13 Cogeneration Systems................................................................................................. 13-1 13.1 Introduction..................................................................................................................................13-1 13.2 History of Cogeneration............................................................................................................. 13-2 13.3 Types of Cogeneration Systems................................................................................................. 13-3 13.3.1 Conventional Cogeneration Systems.......................................................................... 13-3 13.3.1.1 Bottoming Cycle............................................................................................ 13-5 13.3.1.2 Topping Cycle................................................................................................ 13-5 13.3.2 Packaged Cogeneration Systems................................................................................. 13-8 13.3.3 Distributed Generation Technologies........................................................................ 13-8 13.4 Evaluation of Cogeneration Systems.......................................................................................13-10 13.4.1 Efficiency of Cogeneration Systems...........................................................................13-10 13.4.2 Simplified Feasibility Analysis of Cogeneration Systems...................................... 13-12 13.4.3 Financial Options.........................................................................................................13-16 13.5 Case Study....................................................................................................................................13-16 13.6 Summary......................................................................................................................................13-18 14 Heat Recovery Systems............................................................................................... 14-1 14.1 Introduction..................................................................................................................................14-1 14.2 Types of Heat Recovery Systems................................................................................................14-1 14.3 Performance of Heat Recovery Systems....................................................................................14-3 14.4 Simplified Analysis Methods..................................................................................................... 14-6 14.5 Summary......................................................................................................................................14-12 15 Water Management...................................................................................................... 15-1 15.1 Introduction................................................................................................................................. 15-1 15.2 Indoor Water Management........................................................................................................ 15-1 15.2.1 Water-Efficient Plumbing Fixtures............................................................................. 15-2 15.2.1.1 Water-Saving Showerheads......................................................................... 15-2 15.2.1.2 Water-Saving Toilets..................................................................................... 15-2 15.2.1.3 Water-Saving Faucets................................................................................... 15-3 15.2.1.4 Repair Water Leaks....................................................................................... 15-3 15.2.1.5 Water/Energy Efficient Appliances............................................................15-4 15.2.2 Domestic Hot Water Usage..........................................................................................15-4
- 19. xiv Contents 15.3 Outdoor Water Management..................................................................................................... 15-8 15.3.1 Irrigation and Landscaping. ......................................................................................... 15-8 15.3.2 Waste Water Reuse.......................................................................................................15-10 15.4 Swimming Pools.........................................................................................................................15-10 15.4.1 Evaporative Losses........................................................................................................15-11 15.4.2 Impact of Pool Covers................................................................................................. 15-13 15.5 Summary......................................................................................................................................15-14 16 Methods for Estimating Energy Savings. ............................................................... 16-1 16.1 Introduction..................................................................................................................................16-1 16.2 General Procedure....................................................................................................................... 16-2 16.3 Energy Savings Estimation Models.......................................................................................... 16-4 16.3.1 Simplified Engineering Methods................................................................................ 16-4 16.3.2 Regression Analysis Models.........................................................................................16-6 16.3.2.1 Single-Variable Regression Analysis Models............................................16-6 16.3.2.2 Multivariable Regression Analysis Models................................................16-7 16.3.3 Dynamic Models...........................................................................................................16-10 16.3.4 Computer Simulation Models. ................................................................................... 16-13 16.4 Applications.................................................................................................................................16-17 16.5 Uncertainty Analysis.................................................................................................................16-18 16.6 Summary......................................................................................................................................16-19 17 Case Studies....................................................................................................................17-1 17.1 Reporting Guidelines...................................................................................................................17-1 17.1.1 Reporting a Walk-Through Audit................................................................................17-1 17.1.2 Reporting a Standard Audit..........................................................................................17-2 17.2 Case Study 1: Walk-Through Audit of a Residence.................................................................17-4 17.2.1 Building Description......................................................................................................17-4 17.2.1.1 Building Envelope..........................................................................................17-4 17.2.1.2 Building Infiltration......................................................................................17-4 17.2.1.3 HVAC System.................................................................................................17-5 17.2.1.4 Water Management........................................................................................17-5 17.2.1.5 Appliances.......................................................................................................17-5 17.2.1.6 Thermal Comfort...........................................................................................17-5 17.2.2 Energy Efficiency Measures..........................................................................................17-5 17.2.2.1 Building Envelope..........................................................................................17-5 17.2.2.2 Water Management........................................................................................17-6 17.2.2.3 Appliances.......................................................................................................17-6 17.2.3 Economic Analysis.........................................................................................................17-7 17.2.4 Recommendations..........................................................................................................17-7 17.3 Case Study 2: Standard Audit of a Residence...........................................................................17-7 17.3.1 Architectural Characteristics.......................................................................................17-8 17.3.2 Utility Analysis...............................................................................................................17-9 17.3.3 Air Leakage Testing......................................................................................................17-10 17.3.4 Energy Modeling..........................................................................................................17-12 17.3.5 Model Calibration. ........................................................................................................17-13 17.3.6 Energy Conservation Measures. .................................................................................17-14 17.3.7 Conclusions and Recommendations.........................................................................17-16
- 20. Contents xv 17.4 Case Study 3: Audit of a Museum............................................................................................17-17 17.4.1 Building Description....................................................................................................17-17 17.4.1.1 HVAC Systems..............................................................................................17-18 17.4.1.2 Electrical Systems.........................................................................................17-19 17.4.2 Walk-Through Audit....................................................................................................17-20 17.4.2.1 Lighting Systems..........................................................................................17-20 17.4.2.2 Mechanical Systems.....................................................................................17-21 17.4.2.3 Building Shell................................................................................................17-21 17.4.2.4 Other Issues. ..................................................................................................17-21 17.4.3 Utility Data Analysis....................................................................................................17-22 17.4.3.1 Base-Load Determination. ..........................................................................17-22 17.4.3.2 Building Load Characteristics...................................................................17-23 17.4.4 Occupant Survey...........................................................................................................17-23 17.4.5 Field Testing and Measurements................................................................................17-24 17.4.5.1 Lighting Quality...........................................................................................17-24 17.4.5.2 Space Temperature and Humidity Profiles..............................................17-25 17.4.5.3 Thermal Imaging..........................................................................................17-26 17.4.6 Energy Modeling..........................................................................................................17-27 17.4.6.1 Building Envelope, Geometry, and Thermal Zones...............................17-28 17.4.6.2 HVAC Components.....................................................................................17-29 17.4.6.3 Calibration of the Energy Model...............................................................17-31 17.4.7 Analysis of Energy Conservation Measures.............................................................17-32 17.4.7.1 Overview. .......................................................................................................17-32 17.4.8 Energy Savings Estimation. .........................................................................................17-35 17.4.8.1 ECM 1: Delamping 30 Percent of Lamps. .................................................17-35 17.4.8.2 ECM 2: Increased Roof Insulation............................................................17-36 17.4.8.3 ECM 3: Window Replacement...................................................................17-36 17.4.8.4 ECM 4: Occupancy Sensors. .......................................................................17-39 17.4.8.5 ECM 5: Premium Efficiency Pumps..........................................................17-39 17.4.8.6 ECM 6: Improved Fume Hood Controls—Demand-Controlled Ventilation.................................................................................................... 17-40 17.4.8.7 ECM 7: Improved Water Fixture Efficiency.............................................17-41 17.4.8.8 ECM 8: Optimized Package of ECMs...................................................... 17-42 17.4.9 Economic Analysis...................................................................................................... 17-42 17.5 Summary and Recommendations.......................................................................................... 17-44 Appendix A: Conversion Factors....................................................................Appendix A-1 Appendix B: Weather Data................................................................................Appendix B-1 References.................................................................................................................References-1 Index................................................................................................................................... Index-1
- 22. xvii Preface Worldwide, buildings are responsible for over 40 percent of the total primary energy use and related greenhouse emissions. Through standards and energy efficiency programs, several countries have suc- ceeded in improving the energy performance of existing buildings. In 2005, the International Energy Agency estimated that since 1973 energy efficiency improvements have helped save over 50 percent of the energy consumed in the United States compared to the business-as-usual scenario without develop- ment and implementation of such measures (IEA, 2008). However, energy systems currently utilized in buildings are still far from achieving second law thermodynamic limits to efficiency. Even with cur- rent technologies, there is significant potential to improve energy efficiency cost-effectively for both new and existing buildings. The last few decades have seen major improvements in the efficiency of building energy systems including lighting, heating, and cooling equipment. In 2009, a study by the World Council for Sustainable Development (WBCSD) found that several energy efficiency projects were feasible with today’s energy costs. Specifically, the study found that at oil prices of $60 U.S. per bar- rel, investments in existing building energy efficiency technologies can reduce related energy use and carbon footprints by 40 percent in five discounted payback years. Significant investments are being made, especially in the United States and Europe, to further reduce energy consumption attributed to the existing building stock through weatherization, energy auditing, and retrofitting programs. It is a consensus among all countries that well-trained energy auditors are essential to the success of these building energy efficiency programs. It is the purpose of the second edition of this book to provide a training guide for energy auditors and energy managers outlining systematic and well-proven engineering analysis methods and techniques to reduce energy use and operating costs for both residential and commercial buildings. The second edition of the book presents simplified analysis methods to evaluate energy conserva- tion opportunities in buildings. These simplified methods are based on well-established engineering principles. In addition, several innovative yet proven energy efficiency technologies and strategies are presented. The book is designed to be a self-contained textbook aimed at seniors or first-year graduate students. The contents of this book can be covered in a one-semester course in energy management or building energy efficiency. The book can also be used as a reference for practitioners and as a text for continuing education short courses. Users of this book are assumed to have a basic understanding of building energy systems including the fundamentals of heat transfer and principles of heating, ventilat- ing, and air-conditioning (HVAC). General concepts of engineering economics, building energy simu- lation, and building electrical systems are also recommended. The second edition of the book is organized in 17 self-contained chapters. The first three chapters provide basic tools that are typically required to perform energy audits of buildings. Each of the follow- ing 12 chapters addresses a specific building subsystem or energy efficiency technology. The penultimate chapter provides an overview of basic engineering methods used to verify and measure actual energy savings attributed to implementation of energy efficiency projects. The final chapter is devoted to case studies. Each chapter includes some worked-out examples that illustrate the use of simplified analysis
- 23. xviii Preface methods to evaluate the benefits of energy efficient measures or technologies. Problems are provided at the end of most chapters to serve as review or homework problems for users of the book. However, as the instructor of an energy management course at the University of Colorado, I found that the best approach for students to understand and apply the various analysis methods and tools discussed in this book is through group projects consisting of energy audits of real buildings. When using this book as a textbook, the instructor should start at Chapter 1 and proceed through Chapter 17 in order. However, some of the chapters can be skipped or covered lightly depend- ing on time constraints and the background of the students. First, general procedures suitable for building energy audits are presented (Chapter 1). Some of the analysis tools and techniques needed to perform building energy audits are then discussed. In particular, analysis methods are briefly provided for utility rate structures (Chapter 2), economic evaluation of energy efficiency projects (Chapter 3), and energy simulation of buildings (Chapter 4). In buildings, electrical systems con- sume a significant amount of energy. Several energy efficiency strategies and technologies are dis- cussed to reduce energy use from lighting, motors, and appliances (Chapter 5). Various approaches to improve the building envelope are also outlined (Chapter 6). These approaches are particularly suitable for residential buildings characterized by skin-dominated heating/cooling loads. To main- tain acceptable comfort levels, heating and cooling systems typically consume the most energy in a building. Several measures are described to improve the energy efficiency of secondary HVAC systems (Chapter 7), central heating and cooling plants (Chapters 8 and 9), and energy management control systems (Chapter 10). In addition, simple strategies are described to reduce the energy used by compressed air systems, especially in industrial facilities (Chapter 11). Selected technologies to reduce energy use and costs in buildings are discussed, including thermal energy storage systems (Chapter 12), cogeneration (Chapter 13), and heat recovery systems (Chapter 14). Cost-effective measures to improve water management inside and outside buildings are presented (Chapter 15). Analysis methods used for the measurement and verification of actual energy savings attributed to energy efficiency projects are briefly summarized (Chapter 16). Finally, general guidelines to draft reports after completing energy audits are presented with specific examples for three case studies (Chapter 17). A special effort has been made to use metric (SI) units throughout the book. However, in several chapters English (IP) units are also used because they are still the standard set of units used in the United States. Conversion tables between the two unit systems (from English to metric and metric to English) are provided in Appendix A. Appendix B provides annual heating and cooling degree days as well as annual degree hours for various balance temperatures in alphabetic order for countries around the world. Appendix C, located on the CRC Press Web site at URL http://www.crcpress.com/product/ isbn/9781439828717 provides expanded monthly weather data in both SI and IP units for over 300 sites located in both the United States and throughout the world in a searchable format. I wish to acknowledge the assistance of several people in the conception and preparation of this book. Special thanks to Prof. Dominique Marchio, Prof. Irene Arditi, Cederic Carretero, and Prof. Jerome Adnot. The input of several of my students at the University of Colorado at Boulder as well as the encouragement of Dr. Frank Kreith is acknowledged. Finally, I am greatly indebted to my wife Hajer and my children for their continued patience and support throughout the preparation of this second edition of this book. Moncef Krarti
- 24. xix Author MoncefKrarti, PhD, PE, LEED®AP, is professor, associate chair, and director, Building Systems Program, Civil, Environmental, and Architectural Engineering Department at the University of Colorado. He has vast experience in designing, testing, and assessing innovative energy efficiency and renewable energy technologies applied to buildings. He has also directed several projects in the energy management of buildings. In particular, he has conducted over 1,000 energy audits of various residential, commercial, institutional, and industrial facilities. His published textbook Energy Audit of Building Systems, 1st edi- tion is widely used to teach energy audit techniques. Moreover, he has conducted several training work- shops and courses in the energy analysis of building energy systems using state-of-the-art measurement and simulation techniques. In addition to his experience as an international consultant in energy efficiency, Dr. Krarti has been published in over 200 technical journals and handbook chapters in various fields related to energy effi- ciency and energy conservation. As part of his activities as a professor at the University of Colorado, he has administered the energy management center at the University of Colorado. He has also helped the development of similar energy efficiency centers in other countries including Brazil, Mexico, and Tunisia. Dr. Krarti has extensive experience in promoting building energy efficiency technologies and policies overseas, including the development of building energy codes and energy efficiency training programs in several countries, including Tunisia, Sri Lanka, and Egypt and collaborative research with more than 10 countries in Europe, Africa, Asia, and South America.
- 26. 1-1 1.1 Introduction Since the oil embargo of 1973, significant improvements have been made in the energy efficiency of new buildings. However, the vast majority of the existing building stock is more than 20 years old and does not meet current energy efficiency construction standards (IEA, 2008). Therefore, energy retrofits of existing buildings will be required for decades to come if the overall energy efficiency of the building stock is to meet the standards. Investing to improve the energy efficiency of buildings provides an immediate and relatively pre- dictable positive cash flow resulting from lower energy bills. In addition to the conventional financing options available to owners and building operators (such as loans and leases), other methods are avail- able to finance energy retrofit projects for buildings. One of these methods is performance contracting, in which payment for a retrofit project is contingent upon its successful outcome. Typically, an energy services company (ESCO) assumes all the risks for a retrofit project by performing the engineering analysis and obtaining the initial capital to purchase and install equipment needed for energy efficiency improvements. Energy auditing is an important step used by energy service companies to ensure the success of their performance contracting projects. Moreover, several large industrial and commercial buildings have established internal energy man- agement programs based on energy audits to reduce waste in energy use or to comply with the speci- fications of some regulations and standards. Other building owners and operators take advantage of available financial incentives typically offered by utilities or state agencies to perform energy audits and implement energy conservation measures. In the 1970s, building energy retrofits consisted of simple measures such as shutting off lights, turn- ing down heating temperatures, turning up air-conditioning temperatures, and reducing hot water tem- peratures. Today, building energy management includes a comprehensive evaluation of almost all the energy systems within a facility. Therefore, the energy auditor should be aware of key energy issues such as the subtleties of electric utility rate structures and of the latest building energy efficiency technologies and their applications. This chapter describes a general but systematic procedure for energy auditing suitable for both com- mercial buildings and industrial facilities. Some of the commonly recommended energy conservation measures are briefly discussed. A case study for an office building is presented to illustrate the various tasks involved in an energy audit. Finally, an overview is provided to outline the existing methods for measurement and verification of energy savings incurred by the implementation of energy conserva- tion measures. 1 Introduction to Energy Audit
- 27. 1-2 Energy Audit of Building Systems: An Engineering Approach, Second Edition 1.2 Types of Energy Audits The term “energy audit” is widely used and may have different meanings depending on the energy ser- vice company. Energy auditing of buildings can range from a short walk-through of the facility to a detailed analysis with hourly computer simulation. Generally, four types of energy audits can be distin- guished as briefly described below. 1.2.1 Walk-Through Audit This audit consists of a short on-site visit of the facility to identify areas where simple and inexpensive actions can provide immediate energy use or operating-cost savings. Some engineers refer to these types of actions as operating and maintenance (OM) measures. Examples of OM measures include setting back heating set-point temperatures, replacing broken windows, insulating exposed hot water or steam pipes, and adjusting boiler fuel–air ratio. A sample of a walk-through audit for a residence is provided in Chapter 17. 1.2.2 Utility Cost Analysis The main purpose of this type of audit is to carefully analyze the operating costs of the facility. Typically, the utility data over several years is evaluated to identify the patterns of energy use, peak demand, weather effects, and potential for energy savings. To perform this analysis, it is recom- mended that the energy auditor conduct a walk-through survey to get acquainted with the facility and its energy systems. It is important that the energy auditor clearly understand the utility rate structure that applies to the facility for several reasons including: To check the utility charges and ensure that no mistakes were made in calculating the monthly • bills. Indeed, the utility rate structures for commercial and industrial facilities can be quite com- plex with ratchet charges and power factor penalties. To determine the most dominant charges in the utility bills. For instance, peak demand charges • can be a significant portion of the utility bill especially when ratchet rates are applied. Peak shav- ing measures can then be recommended to reduce these demand charges. To identify whether the facility can benefit from using other utility rate structures to purchase • cheaper fuel and reduce its operating costs. This analysis can provide a significant reduction in the utility bills especially with implementation of electrical deregulation and the advent of real-time pricing (RTP) rate structures. Moreover, the energy auditor can determine whether the facility is a candidate for energy retrofit projects by analyzing the utility data. Indeed, the energy use of the facility can be normalized and com- pared to indices (for instance, the energy use per unit of floor area—for commercial buildings—or per unit of a product—for industrial facilities—as discussed in Chapter 4). 1.2.3 Standard Energy Audit The standard audit provides a comprehensive energy analysis for the energy systems of the facility. In addition to the activities described for the walk-through audit and for the utility cost analysis described above, the standard energy audit includes the development of a baseline for the energy use of the facil- ity and the evaluation of the energy savings and the cost-effectiveness of appropriately selected energy
- 28. Introduction to Energy Audit 1-3 conservation measures. The step-by-step approach of the standard energy audit is similar to that of the detailed energy audit described later on in the following section. Typically, simplified tools are used in the standard energy audit to develop baseline energy models and to predict the energy savings of energy conservation measures. Among these tools are the degree-day methods and linear regression models (Fels, 1986). In addition, a simple payback analysis is generally performed to determine the cost-effectiveness of energy conservation measures. Examples of standard audits are provided in Chapter 17. 1.2.4 Detailed Energy Audit This audit is the most comprehensive but also time-consuming energy audit type. Specifically, the detailed energy audit includes the use of instruments to measure energy use for the whole building or for some energy systems within the building (for instance, by end uses: lighting systems, office equipment, fans, chillers, etc.). In addition, sophisticated computer simulation programs are typically considered for detailed energy audits to evaluate and recommend energy retrofits for the facility. The techniques available to perform measurements for an energy audit are diverse. During the on- site visit, handheld and clamp-on instruments can be used to determine the variation of some building parameters such as the indoor air temperature, luminance level, and electrical energy use. When long- term measurements are needed, sensors are typically used and connected to a data-acquisition system so measured data can be stored and be accessible remotely. Recently, nonintrusive load monitoring (NILM) techniques have been proposed (Shaw et al., 2005). The NILM technique can determine the real-time energy use of the significant electrical loads in a facility using only a single set of sensors at the facility service entrance. The minimal effort associated with using the NILM technique when compared to the traditional submetering approach (which requires a separate set of sensors to monitor energy consumption for each end-use) makes the NILM a very attractive and inexpensive load-monitoring technique for energy service companies and facility owners. The computer simulation programs used in the detailed energy audit can typically provide the energy use distribution by load type (i.e., energy use for lighting, fans, chillers, boilers, etc.). They are often based on dynamic thermal performance of the building energy systems and typically require a high level of engineering expertise and training. These simulation programs range from those based on the bin method (Knebel, 1983) to those that provide hourly building thermal and electrical loads such as DOE-2 (LBL, 1980). The reader is referred to Chapter 4 for more detailed discussion of the energy analysis tools that can be used to estimate energy and cost savings attributed to energy conservation measures. In the detailed energy audit, more rigorous economic evaluation of the energy conservation measures are generally performed. Specifically, the cost-effectiveness of energy retrofits may be determined based on the life-cycle cost (LCC) analysis rather than the simple payback period analysis. Life-cycle cost analysis takes into account a number of economic parameters such as interest, inflation, and tax rates. Chapter 3 describes some of the basic analytical tools that are often used to evaluate energy efficiency projects. 1.3 General Procedure for a Detailed Energy Audit To perform an energy audit, several tasks are typically carried out depending on the type of audit and the size and function of the audited building. Some of the tasks may have to be repeated, reduced in scope, or even eliminated based on the findings of other tasks. Therefore, the execution of an energy audit is often not a linear process and is rather iterative. However, a general procedure can be outlined for most buildings.
- 29. 1-4 Energy Audit of Building Systems: An Engineering Approach, Second Edition 1.3.1 Step 1: Building and Utility Data Analysis The main purpose of this step is to evaluate the characteristics of the energy systems and the patterns of energy use for the building. The building characteristics can be collected from the architectural/ mechanical/electrical drawings or from discussions with building operators. The energy use patterns can be obtained from a compilation of utility bills over several years. Analysis of the historical variation of the utility bills allows the energy auditor to determine if there are any seasonal and weather effects on the building energy use. Some of the tasks that can be performed in this step are presented below and the key results expected from each task are noted: Collect at least three years of utility data (to identify a historical energy use pattern). • Identify the fuel types used (electricity, natural gas, oil, etc., to determine the fuel type that • accounts for the largest energy use). Determine the patterns of fuel use by fuel type (to identify the peak demand for energy use by • fuel type). Understand utility rate structure (energy and demand rates; to evaluate if the building is penal- • ized for peak demand and if cheaper fuel can be purchased). Analyze the effect of weather on fuel consumption (to pinpoint any variations of energy use • related to extreme weather conditions). Perform utility energy use analysis by building type and size (building signature can be deter- • mined including energy use per unit area: to compare against typical indices). 1.3.2 Step 2: Walk-Through Survey From this step, potential energy savings measures should be identified. The results of this step are important because they determine if the building warrants any further energy auditing work. Some of the tasks involved in this step are Identify the customer concerns and needs. • Check the current operating and maintenance procedures. • Determine the existing operating conditions of major energy use equipment (lighting, HVAC • systems, motors, etc.). Estimate the occupancy, equipment, and lighting (energy use density and hours of operation). • 1.3.3 Step 3: Baseline for Building Energy Use The main purpose of this step is to develop a base-case model that represents the existing energy use and operating conditions for the building. This model is to be used as a reference to estimate the energy savings incurred from appropriately selected energy conservation measures. The major tasks to be per- formed during this step are Obtain and review architectural, mechanical, electrical, and control drawings. • Inspect, test, and evaluate building equipment for efficiency, performance, and reliability. • Obtain all occupancy and operating schedules for equipment (including lighting and HVAC • systems). Develop a baseline model for building energy use. • Calibrate the baseline model using the utility data or metered data. • 1.3.4 Step 4: Evaluation of Energy Savings Measures In this step, a list of cost-effective energy conservation measures is determined using both energy sav- ings and economic analysis. To achieve this goal, the following tasks are recommended:
- 30. Introduction to Energy Audit 1-5 Prepare a comprehensive list of energy conservation measures (using the information collected in • the walk-through survey). Determine the energy savings due to the various energy conservation measures pertinent to the • building using the baseline energy use simulation model developed in Step 3. Estimate the initial costs required to implement the energy conservation measures. • Evaluate the cost-effectiveness of each energy conservation measure using an economic analysis • method (simple payback or life-cycle cost analysis). Tables 1.1 and 1.2 provide summaries of the energy audit procedure recommended for commercial buildings and for industrial facilities, respectively. Energy audits for thermal and electrical systems are separated because they are typically subject to different utility rates. 1.4 Common Energy Conservation Measures In this section some energy conservation measures (ECMs) commonly recommended for commer- cial and industrial facilities are briefly discussed. It should be noted that the list of ECMs presented below does not pretend to be exhaustive nor comprehensive. It is provided merely to indicate some of the options that the energy auditor can consider when performing an energy analysis of a com- mercial or industrial facility. More discussion of energy efficiency measures for various building energy systems is provided in later chapters of this book. However, it is strongly advised that the energy auditor keep abreast of any new technologies that can improve building energy efficiency. Moreover, the energy auditor should only recommend the ECMs based on a sound economic analy- sis for each ECM. 1.4.1 Building Envelope For some buildings, the envelope (i.e., walls, roofs, floors, windows, and doors) can have an important impact on the energy used to condition the facility. The energy auditor should determine the actual characteristics of the building envelope. During the survey, a descriptive sheet for the building envelope should be established to include information such as construction materials (for instance, the level of insulation in walls, floors, and roofs), the area, and the number of building envelope assemblies (for instance, the type and the number of panes for the windows). In addition, comments on the repair needs and recent replacements should be noted during the survey. Some of the commonly recommended energy conservation measures to improve the thermal perfor- mance of the building envelope are 1. Addition of thermal insulation. For building surfaces without any thermal insulation, this mea- sure can be cost-effective. 2. Replacement of windows. When windows represent a significant portion of the exposed building surfaces, using more energy-efficient windows (high R-value, low-emissivity glaz- ing, airtight, etc.) can be beneficial in both reducing the energy use and improving the indoor comfort level. 3. Reduction of air leakage. When the infiltration load is significant, leakage area of the building envelope can be reduced by simple and inexpensive weatherstripping techniques. The energy audit of the envelope is especially important for residential buildings. Indeed, the energy use from residential buildings is dominated by weather inasmuch as heat gain or loss from direct conduc- tion of heat or from air infiltration/exfiltration through building surfaces accounts for a major portion (50 to 80 percent) of the energy consumption. For commercial buildings, improvements to the building
- 31. 1-6 Energy Audit of Building Systems: An Engineering Approach, Second Edition envelope are often not cost-effective due to the fact that modifications to the building envelope (replac- ing windows, adding thermal insulation in walls) are typically considerably expensive. However, it is recommended to audit the envelope components systematically not only to determine the potential for energy savings but also to ensure the integrity of its overall condition. For instance, thermal bridges—if present—can lead to a heat transfer increase and to moisture condensation. The moisture condensation is often more damaging and costly than the increase in heat transfer because it can affect the structural integrity of the building envelope. TABLE 1.1 Energy Audit Summary for Residential and Commercial Buildings Phase Thermal Systems Electric Systems Utility analysis Thermal energy use profile (building • signature) Thermal energy use per unit area (or per • student for schools or per bed for hospitals) Thermal energy use distribution • (heating, DHW, process, etc.) Fuel types used • Weather effect on thermal energy use • Utility rate structure • Electrical energy use profile (building • signature) Electrical energy use per unit area (or per • student for schools or per bed for hospitals) Electrical energy use distribution (cooling, • lighting, equipment, fans, etc.) Weather effect on electrical energy use • Utility rate structure (energy charges, • demand charges, power factor penalty, etc.) On-site survey Construction materials (thermal • resistance type and thickness) HVAC system type • DHW system • Hot water/steam use for heating • Hot water/steam for cooling • Hot water/steam for DHW • Hot water/steam for specific applications • (hospitals, swimming pools, etc.) HVAC system type • Lighting type and density • Equipment type and density • Energy use for heating • Energy use for cooling • Energy use for lighting • Energy use for equipment • Energy use for air handling • Energy use for water distribution • Energy use baseline Review architectural, mechanical, and • control drawings Develop a base-case model (using any • baselining method ranging from very simple to more detailed tools) Calibrate the base-case model (using • utility data or metered data) Review architectural, mechanical, electrical, • and control drawings Develop a base-case model (using any • baselining method ranging from very simple to more detailed tools) Calibrate the base-case model (using utility • data or metered data) Energy conservation measures Heat recovery system (heat exchangers) • Efficient heating system (boilers) • Temperature setback • EMCS • HVAC system retrofit • DHW use reduction • Cogeneration • Energy efficient lighting • Energy efficient equipment (computers) • Energy efficient motors • HVAC system retrofit • EMCS • Temperature setup • Energy efficient cooling system (chiller) • Peak demand shaving • Thermal energy storage system • Cogeneration • Power factor improvement • Reduction of harmonics •
- 32. Introduction to Energy Audit 1-7 1.4.2 Electrical Systems For most commercial buildings and a large number of industrial facilities, the electrical energy cost constitutes the dominant part of the utility bill. Lighting, office equipment, and motors are the electrical systems that consume the major part of energy in commercial and industrial buildings. 1. Lighting. Lighting for a typical office building represents on average 40 percent of the total electrical energy use. There is a variety of simple and inexpensive measures to improve the efficiency of lighting systems. These measures include the use of energy-efficient lighting lamps and ballasts, the addition of reflective devices, delamping (when the luminance levels are above the recommended levels by the standards), and the use of daylighting controls. Most lighting measures are especially cost-effective for office buildings for which payback periods are less than one year. TABLE 1.2 Energy Audit Summary for Industrial Facilities Phase Thermal Systems Electric Systems Utility analysis Thermal energy use profile (building • signature) Thermal energy use per unit of a product • Thermal energy use distribution • (heating, process, etc.) Fuel types used • Analysis of the thermal energy input for • specific processes used in the production line (such as drying) Utility rate structure • Electrical energy use profile (building • signature) Electrical energy use per unit of a product • Electrical energy use distribution (cooling, • lighting, equipment, process, etc.) Analysis of the electrical energy input for • specific processes used in the production line (such as drying) Utility rate structure (energy charges, • demand charges, power factor penalty, etc.) On-site survey List of equipment that uses thermal • energy Perform heat balance of the thermal • energy Monitor of thermal energy use of all or • part of the equipment Determine the by-products of thermal • energy use (such as emissions and solid waste) List of equipment that uses electrical energy • Perform heat balance of the electrical energy • Monitor electrical energy use of all or part of • the equipment Determine the by-products of electrical • energy use (such as pollutants) Energy use baseline Review mechanical drawings and • production flow charts Develop a base-case model using (any • baselining method) Calibrate the base-case model (using • utility data or metered data) Review electrical drawings and production • flow charts Develop a base-case model (using any • baselining method) Calibrate the base-case model (using utility • data or metered data) Energy conservation measures Heat recovery system • Efficient heating and drying system • EMCS • HVAC system retrofit • Hot water and steam use reduction • Cogeneration (possibly with solid waste • from the production line) Energy efficient motors • Variable speed drives • Air compressors • Energy efficient lighting • HVAC system retrofit • EMCS • Cogeneration (possibly with solid waste from • the production line) Peak demand shaving • Power factor improvement • Reduction of harmonics •
- 33. 1-8 Energy Audit of Building Systems: An Engineering Approach, Second Edition 2. Oἀ ce Equipment. Office equipment constitutes the fastest growing part of the electrical loads especially in commercial buildings. Office equipment includes computers, fax machines, printers, and copiers. Today, there are several manufacturers that provide energy-efficient office equipment (such those that comply with the U.S. EPA Energy Star specifications). For instance, energy-effi- cient computers automatically switch to a low-power “sleep” mode or off mode when not in use. 3. Motors. The energy cost to operate electric motors can be a significant part of the operating bud- get of any commercial or industrial building. Measures to reduce the energy cost of using motors include reducing operating time (turning off unnecessary equipment), optimizing motor systems, using controls to match motor output with demand, using variable speed drives for air and water distribution, and installing energy-efficient motors. Table 1.3 provides typical efficiencies for sev- eral motor sizes. In addition to the reduction in total facility electrical energy use, retrofits of the electrical systems decrease space cooling loads and therefore further reduce the electrical energy use in the building. These cooling energy reductions as well as possible increases in thermal energy use (for space heating) should be accounted for when evaluating the cost-effectiveness of improvements in lighting and office equipment. 1.4.3 HVAC Systems The energy use due to HVAC systems can represent 40 percent of the total energy consumed by a typical commercial building. The energy auditor should obtain the characteristics of major HVAC equipment to determine the condition of the equipment, operating schedule, quality of maintenance, and control procedures. A large number of measures can be considered to improve the energy performance of both primary and secondary HVAC systems. Some of these measures are listed below: 1. Setting Up/Back Thermostat Temperatures: When appropriate, setback of heating temperatures can be recommended during unoccupied periods. Similarly, setup of cooling temperatures can be considered. 2. Retrofit of Constant Air Volume Systems: For commercial buildings, variable air volume (VAV) systems should be considered when the existing HVAC systems rely on constant volume fans to condition part or the entire building. 3. Installation of Heat Recovery Systems: Heat can be recovered from some HVAC equipment. For instance, heat exchangers can be installed to recover heat from air handling unit (AHU) exhaust air streams and from boiler stacks. TABLE 1.3 Typical Efficiencies of Motors Motor Size (Hp) Standard Efficiency (%) Premium Efficiency (%) 1 73.0 85.5 2 75.0 86.5 3 77.0 86.5 5 80.0 89.5 7.5 82.0 89.5 10 85.0 91.7 15 86.0 92.4 20 87.5 93.0 30 88.0 93.6 40 88.5 93.6 50 89.5 94.1
- 34. Introduction to Energy Audit 1-9 4. Retrofit of Central Heating Plants: The efficiency of a boiler can be drastically improved by adjust- ing the fuel–air ratio for proper combustion. In addition, installation of new energy-efficient boil- ers can be economically justified when old boilers are to be replaced. 5. Retrofit of Central Cooling Plants: Currently, there are several chillers that are energy-efficient and easy to control and operate and are suitable for retrofit projects. It should be noted that there is a strong interaction among various components of the heating and cooling system. Therefore, a whole-system analysis approach should be followed when retrofitting a building HVAC system. Optimizing the energy use of a central cooling plant (which may include chill- ers, pumps, and cooling towers) is one example of using a whole-system approach to reduce the energy use for heating and cooling buildings. 1.4.4 Compressed Air Systems Compressed air has become an indispensable tool for most manufacturing facilities. Its uses range from air-powered hand tools and actuators to sophisticated pneumatic robotics. Unfortunately, staggering amounts of compressed air are currently wasted in a large number of facilities. It is estimated that only a fraction of 20 to 25 percent of input electrical energy is delivered as useful compressed air energy. Leaks are reported to account for 10 to 50 percent of the waste and misapplication accounts for 5 to 40 percent of loss in compressed air (Howe and Scales, 1998). To improve the efficiency of compressed air systems, the auditor can consider several issues includ- ing whether compressed air is the right tool for the job (for instance, electric motors are more energy efficient than air-driven rotary devices), how compressed air is applied (for instance, lower pressures can be used to supply pneumatic tools), how it is delivered and controlled (for instance, the compressed air needs to be turned off when the process is not running), and how the compressed air system is managed (for each machine or process, the cost of compressed air needs to be known to identify energy and cost savings opportunities). 1.4.5 Energy Management Controls With the constant decrease in the cost of computer technology, automated control of a wide range of energy systems within commercial and industrial buildings is becoming increasingly popular and cost- effective. An energy management and control system (EMCS) can be designed to control and reduce the building energy consumption within a facility by continuously monitoring the energy use of vari- ous pieces of equipment and making appropriate adjustments. For instance, an EMCS can automati- cally monitor and adjust indoor ambient temperatures, set fan speeds, open and close air handling unit dampers, and control lighting systems. If an EMCS is already installed in the building, it is important to recommend a system tune-up to ensure that the controls are operating properly. For instance, the sensors should be calibrated regularly in accordance with manufacturers’ specifications. Poorly calibrated sensors may cause an increase in heating and cooling loads and may reduce occupant comfort. 1.4.6 Indoor Water Management Water and energy savings can be achieved in buildings by using water-saving fixtures instead of con- ventional fixtures for toilets, faucets, showerheads, dishwashers, and clothes washers. Savings can also be achieved by eliminating leaks in pipes and fixtures. Table 1.4 provides typical water use of conventional and water-efficient fixtures for various end-uses. In addition, Table 1.4 indicates the hot water use by each fixture as a fraction of the total water. With water- efficient fixtures, savings of 50 percent of water use can be achieved for toilets, showers, and faucets.
- 35. 1-10 Energy Audit of Building Systems: An Engineering Approach, Second Edition 1.4.7 New Technologies The energy auditor may consider the potential of implementing and integrating new technologies within the facility. It is therefore important that the energy auditor understand these new technologies and know how to apply them. Among the new technologies that can be considered for commercial and industrial buildings are 1. Building Envelope technologies: Recently several materials and systems have been proposed to improve the energy efficiency of the building envelope and especially windows including: Spectrally selective glasses that can optimize solar gains and shading effects. Chromogenic glazings that change their properties automatically depending on temperature or light-level conditions (similar to sunglasses that become dark in sunlight). Building integrated photovoltaic panels that can generate electricity while absorbing solar radiation and reducing heat gain through the building envelope (typically roofs). 2. Light Pipe technologies: Although the use of daylighting is straightforward for perimeter zones that are near windows, it is not usually feasible for interior spaces, particularly those without any skylights. Recent but still emerging technologies allow the engineer to “pipe” light from roof or wall-mounted collectors to interior spaces that are not close to windows or skylights. 3. HVAC systems and controls: Several strategies can be considered for energy retrofits including: Heat recovery technologies such as rotary heat wheels and heat pipes can recover 50 to 80 per- cent of the energy used to heat or cool ventilation air supplied to the building. Desiccant-based cooling systems are now available and can be used in buildings with large dehumidification loads during long periods (such as hospitals, swimming pools, and super- market fresh produce areas). Geothermal heat pumps can provide an opportunity to take advantage of the heat stored underground to condition building spaces. Thermal energy storage (TES) systems offer a means of using less-expensive off-peak power to produce cooling or heating to condition the building during on-peak periods. Several optimal control strategies have been developed in recent years to maximize the cost savings of using TES systems. 4. Cogeneration: This is not really a new technology. However, recent improvements in its combined thermal and electrical efficiency have made cogeneration cost-effective in several applications including institutional buildings such as hospitals and universities. 1.5 Case Study To illustrate the energy audit process described above, a case study is presented in this section. The activities performed for each step of the energy audit are briefly described. For more details about the TABLE 1.4 Usage Characteristics of Water-Using Fixtures End-Use Conventional Fixtures Water-Efficient Fixtures Usage Pattern % Hot water Toilets 3.5 gal/flush 1.6 gal/flush 4 flushes/pers/day 0 Showers 5.0 gal/min 2.5 gal/min 5 min./shower 60 Faucets 4.0 gal/min 2.0 gal/min 2.5 min/pers/day 50 Dishwashers 14.0 gal/load 8.5 gal/load 0.17 loads/pers/day 100 Clothes washers 55.0 gal/load 42.0 gal/load 0.3 loads/pers/day 25 Leaks 10% of total use 2% of total use N/A 50
- 36. Introduction to Energy Audit 1-11 case study, the reader is referred to Kim et al. (1998). Other case studies are presented in Chapter 17 of this book. The building analyzed in this case study is a medium-size office building located in Seoul, Korea. Figure 1.1 shows the front view of the building. 1.5.1 Step 1: Building and Utility Data Analysis The first step in the building energy audit process is to collect all available information about the energy systems and the energy use pattern of the building. This information was collected before the field sur- vey. In particular, from the architectural/mechanical/electrical drawings and utility bills, the following information and engineering data were gathered: Building Characteristics: The building is a 26-story office building with 2-story penthouse and 4-story basement. It is located in downtown Seoul, Korea. The structure of the building consists of modular concrete and steel frame. The building area is 3,920 m2 and the site area is 6,555 m2. Single glazed windows are installed throughout the building. Figure 1.2 shows a typical floor plan of the building. Table 1.5 describes the various construction materials used throughout the building. Energy Use: Figure 1.3 summarizes the monthly electrical energy use of the building for 1993. The monthly average dry-bulb outdoor air temperatures recorded during 1993 are also pre- sented in Figure 1.3. It is clear that the electrical energy use increases during the sum- mer months (June through October) when the outdoor temperatures are high. During the other months, the electrical energy use is almost constant and can mostly be attributed to lighting and office equipment. Preliminary analysis of the metered building energy use indicated that natural gas consumption is inconsistent from month to month. For example, gas consumption during January is six times higher than during December, even though the weather conditions are similar for both months. Therefore, the recorded data for the natural gas use were considered unreliable and only metered electrical energy use data were analyzed. FIGURE 1.1 Front view of the audited office building.
- 37. 1-12 Energy Audit of Building Systems: An Engineering Approach, Second Edition FIGURE 1.2 Typical floor plan of the audited office building. TABLE 1.5 Building Construction Materials Component Materials Exterior wall 5 cm tile 16 cm concrete 2.5 cm foam insulation 0.6 cm finishing material Roof 5 cm lightweight concrete 15 cm concrete 2.5 cm foam insulation Interior wall 2 cm finishing cement mortar 19 cm concrete block 2 cm finishing cement mortar Glazing 1.2 cm thick single pane glazing Underground wall 25 cm concrete Asphalt shingle Air-space 10 cm brick 2 cm finishing cement mortar Underground floor 15 cm concrete Asphalt shingle 12 cm concrete 2 cm finishing cement mortar
- 38. Introduction to Energy Audit 1-13 1.5.2 Step 2: On-Site Survey A one-day field survey was conducted with the assistance of the building operator during the summer of 1996. During the survey, much useful and revealing information and engineering data were collected. For instance: It was found that the building had been retrofitted with energy-efficient lighting systems. The • measurement of luminance levels throughout the working areas indicated adequate lighting. To determine an estimate of the energy use for lighting, the number and type of lighting fixtures were recorded. It was observed that the cooling and heating temperature set-points were set to be 25.5°C and • 24.5°C, respectively. However, indoor air temperature and relative humidity measurements dur- ing the field survey revealed that during the afternoon, the thermal conditions are uncomfortable in several office spaces with average air dry-bulb temperature of 28°C and relative humidity of 65 percent. A discussion with the building operator indicated that the chillers are no longer able to meet the cooling loads after the addition of several computers in the building during the last few years. As a solution an ice storage tank was then added to reduce the peak cooling load. It was discovered during the survey that the building is heated and cooled simultaneously by two • systems: constant air volume (CAV) and fan coil unit (FCU) systems. The CAV system is comple- mented by the FCU system as necessary. Two air-handling units serve the entire building, and about 58 FCUs are located on each floor. The heating and cooling plant consists of three boilers, six chillers, three cooling towers, and one • ice storage tank. The capacity of the boilers and the chillers is provided below: Boilers: 13 MBtuh (2 units) and 3.5 Mbtuh (1 unit) • Chillers: 215 tons (5 units) and 240 tons (1 unit) • The thermal energy storage system consists of a brine ice-on-coil tank. The charging and discharging hours are 10 and 13, respectively. The TES system is currently controlled using simple and nonpredictive storage-priority controls. The building has relatively high internal heat gains. Some of the building internal heat gain sources are listed in Table 1.6. Operating schedules were based on the discussion with the building operators and on observations during the field survey. Jan Feb Mar Apr May Jun Jul Month Monthly Electrical Energy Use Energy Use (MWh) Aug Sep Oct Nov Dec 0 200 400 600 800 1000 1200 1400 1600 –5 0 5 10 15 20 25 30 Monthly Average Outdoor Temperature(°C) MWh 93 DB 5(°C) FIGURE 1.3 Monthly actual electrical energy consumption.
- 39. 1-14 Energy Audit of Building Systems: An Engineering Approach, Second Edition 1.5.3 Step 3: Energy Use Baseline Model To model the building using DOE-2, each floor was divided into two perimeter and two core zones. Figure 1.4 shows the zone configuration used to model the building floors. The main reason for this zoning configuration is the lack of flexibility in the DOE-2 SYSTEMS program. Although the actual building is conditioned by the combination of constant air volume and fan coil unit systems, the SYSTEM module of DOE-2.1E cannot model two different types of HVAC systems serving one zone. Therefore, a simplification has been made to simulate the actual HVAC system of the building. This sim- plification consists of the following. The perimeter zone is conditioned by the FCUs, whereas the core zone is conditioned by the CAV. Because all the FCUs are located at the perimeter, this simplification is consistent with the actual HVAC system operation. Figure 1.5 shows the monthly electrical energy consumption predicted by the DOE-2 base model and the actual energy use recorded in 1993 for the building. It shows that DOE-2 predicts the actual energy use pattern of the building fairly well, except for the months of September and October. The difference between the annual metered energy use in the building and the annual predicted electric- ity use by the DOE-2 base-case model is about 762 MWh. DOE-2 predicts that the building con- sumes 6 percent more electricity than the actual metered annual energy use. To develop the DOE-2 base-case model, a TRY-type weather file of Seoul was created using the raw weather data collected for 1993. Using the DOE-2 base-case model, a number of ECOs (energy conservation opportunities) can be evaluated. Figure 1.6 shows the distribution by end-uses of the building energy use. The electrical energy con- sumption of the building is dominated by lighting and equipment. The electricity consumption for light- ing and office equipment represents about 75 percent of the total building electricity consumption. As mentioned earlier, a recent lighting retrofit has been performed in the building using electronic ballasts and energy-efficient fluorescent fixtures. Therefore, it was decided not to consider a lighting retrofit as an ECO for this study. The electricity consumption for cooling is about 13.1 percent. The ECOs selected for this building mostly attempt to reduce the cooling loads in order to improve indoor thermal comfort as well as save building energy cost. TABLE 1.6 Internal Heat Gain Level for the Office Building Internal Heat Gain Design Load Occupancy 17 m2/person; Latent heat gain: 45 W Sensible heat gain: 70 W Lighting 14 W/m2 Equipment 16 W/m2 Ventilation 14.7 CFM/person SWP SWP FWP FEP FEC 1st Floor FWC RWP REP REC Reference Floor RWC SWP 2nd Floor SWC FIGURE 1.4 Building zoning configuration for DOE-2 computer simulation.
- 40. Introduction to Energy Audit 1-15 1.5.4 Step 4: Evaluation of Energy Conservation Opportunities (ECOs) Based on the evaluation of the energy use pattern of the building, several energy conservation opportu- nities for the building were analyzed. Among the ECOs considered in the study, six of them successfully reduced energy consumption: ECO #1: CAV to VAV conversion: The present AHU fans are all constant speed fans. They supply conditioned air through a constant volume air-supply system to the conditioned zones. The system is designed to supply enough air to heat or cool the building under design conditions. Under nondesign conditions, more air than needed is supplied. Changing the system to a variable-air-volume system would reduce the amount of air supplied by the AHUs and result in less energy to condition the various zones. For this ECO, the constant-volume reheat fan Area lights 38% Electricity Use Categories of the Building Total = 11723 MWh Space heat 2% Misc equipmt 49% Heat reject 2% Space cool 13% Pumps misc vent fans 8% FIGURE 1.6 Electricity use distribution. Jan Feb Mar Apr May Jun Jul Month DOE-2 Predictions Against Actual Energy Use Actual MWh DOE-2 MWh Energy Use (MWh) Aug Sep Oct Nov Dec 0 200 400 600 800 1000 1200 1400 1600 FIGURE 1.5 Comparison of DOE-2 prediction and actual building electrical energy use.
- 41. 1-16 Energy Audit of Building Systems: An Engineering Approach, Second Edition system assigned for the core zones in the building was changed to a VAV system. In particular, VAV boxes—controlled by the space thermostat—are proposed to vary the amount of condi- tioned air supplied to the building zones to control the indoor temperature. Both labor and equipment costs were included in the estimation of the payback period for this measure. ECO #2: Optimal ice storage control: The current TES system is operated using a nonpredictive storage-priority control. To improve the benefits of the TES system, a near-optimal controller is suggested. This ECO is analyzed to determine if the cost of electrical energy consumption for the building is reduced when a near-optimal control strategy is used. To determine the sav- ings of this option, the simulation environment developed by Henze, Krarti, and Brandemuehl (1997a) is used. This simulation environment is based on a dynamic programming technique and determines the best operating controls for the TES system given the cooling and noncool- ing load profiles and electrical rate structure. No DOE-2 simulation is performed for this ECO. The results of the dynamic programming simulation indicate that an energy use reduction of 5 percent can be achieved using a near-optimal control in lieu of the storage-priority control. To implement this near-optimal control, a predictor is required to determine future building cooling or noncooling loads. An example of such a predictor could be based on neural net- works (Kreider et al., 1995). The labor cost and the initial cost of adding some sensors and a computer were considered to determine the payback period for this measure. ECO #3: Glazing retrofit: For this building, low-e glazing systems are considered to reduce the internal heat gain due to solar radiation. Thus, the cooling load is reduced. In addition, the increased U-value of the glazing reduces the heating load. For this ECO, the existing single pane windows with the glass conductance of 6.17 (W/m2-K) and the shading coefficient of 0.69 were changed to the double-pane windows. These double-pane windows reduce both the glass conductance and the shading coefficient to 1.33 (W/m2-K) and 0.15, respectively. ECO #4: Indoor temperature setback/setup: In this ECO, the impact of the indoor temperature set- ting on the building energy use is analyzed using the DOE-2 simulation program; the heating temperature was set from 24.5°C to 22.5°C and the cooling temperature was set from 25.5°C to 27.5°C. There is only the labor cost associated with this measure. ECO #5: Motor replacement: Increasing the efficiency of the motors for fans and pumps can reduce the total electric energy consumption in the building. In this ECO, the existing efficiencies for the motors were assumed to range from 0.85 (for 10 hp motors) to 0.90 (for 50 hp motors). Energy-efficient motors have efficiencies that range from 0.91 (for 10 hp motors) to 0.95 (for 50 hp motors). Only the differential cost was considered in the economic analysis. ECO #6: Daylighting control plan: A continuous dimming control would regulate the light level so that the luminance level inside the zones remained constant. The electricity consumption of the building can be significantly reduced, and the gas consumption can be slightly increased because of the reduced space heat gain from the lighting system. For this ECO, a daylighting system with continuous dimming control was considered for perimeter office zones. The impact of the selected ECOs on electricity use in the building as predicted by DOE-2 simula- tions is shown in Table 1.7. Based on these results, “converting CAV to VAV” and “implementing daylighting control system with dimming control” reduces the total electricity consumption of the building 5.2 and 7.3 percent, respectively. These savings are significant considering that the electricity consumption for the cooling plant alone is about 13.1 percent of the total electricity consumption of the building. The economic analysis was performed using the utility rate of Seoul, Korea. Table 1.7 presents the energy cost savings of ECOs in Korean currency (1,000 Won = $1 U.S.). In addition to the electricity cost, the natural gas cost was also included in the economic analysis. The natural gas is used only for heating the building. The economic analysis shows that the VAV conversion reduces the total building energy cost by more than 10 percent, and the daylighting control saves about 6 percent of the total energy costs.
- 42. Introduction to Energy Audit 1-17 1.5.5 Step 5: Recommendations From the results for economic analysis, the VAV conversion (ECO #1), adjustment of temperature set- point (ECO #4), and the daylighting control (ECO #6) are the recommended energy-saving opportuni- ties to be implemented for the audited office building. 1.6 Verification Methods of Energy Savings Energy conservation retrofits are deemed cost-effective based on predictions of energy and cost savings. However, several studies have found that large discrepancies exist between actual and predicted energy sav- ings. Due to the significant increase in the activities of energy service companies (ESCOs), the need became evidentforstandardizedmethodsformeasurementandverificationofenergysavings.Thisinterestledtothe development of the North American Energy Measurement and Verification Protocol published in 1996 and later expanded and revised under the International Performance Measurement and Verification Protocol. In principle, the measurement of the retrofit energy savings can be obtained by simply comparing the energy use during pre- and postretrofit periods. Unfortunately, the change in energy use between the pre- and postretrofit periods is not only due to the retrofit itself but also to other factors such as changes in weather conditions, levels of occupancy, and HVAC operating procedures. It is important to account for all these changes to determine the retrofit energy savings accurately. Several methods have been proposed to measure and verify energy savings of implemented energy conservation measures in commercial and industrial buildings. Chapter 16 describes a number of meth- ods suitable for measurement and verification of energy savings. Some of these techniques are briefly described below: 1. Regression Models: The early regression models used to measure savings adapted the variable-base degree-day (VBDD) method. Among these early regression models, the Princeton scorekeeping method (PRISM) was used to measure monthly energy consumption data and daily average tem- peratures to calibrate a linear regression model and determine the best values for nonweather- dependent consumption, the temperature at which the energy consumption began to increase due to heating or cooling (the change-point or base temperature), and the rate at which the energy consumption increased. Several studies have indicated that the simple linear regression model is suitable for estimating energy savings for residential buildings. However, subsequent work has shown that the PRISM model does not provide accurate estimates for energy savings for most commercial buildings (Ruch and Claridge, 1992). Single-variable (temperature) regression mod- els require the use of at least four-parameter segmented linear or change-point regressions to be suitable for commercial buildings. Katipamula, Reddy, and Claridge (1994) proposed mul- tiple linear regression models to include as independent variables internal gain, solar radiation, wind, and humidity ratio in addition to the outdoor temperature. For the buildings considered in TABLE 1.7 Economic Analysis of the ECOs Electricity Cost (MWon) LNG Cost (MWon) Total Cost (MWon) Capital Cost (MWon) Saving (%) Savings (MWon) Payback Period (Years) Base Case 984.4 139.1 1,123.5 — — — — ECO #1 940.8 49.8 990.5 465.5 11.8 133.0 3.5 ECO #2 979.1 139.1 1,118.2 42.4 0.6 5.3 8.0 ECO #3 977.9 126.9 1,104.8 280.5 1.7 18.7 15.0 ECO #4 983.7 106.4 1,090.1 16.7 3.0 33.4 0.5 ECO #5 972.6 138.7 1,111.4 60.5 1.1 12.1 5.0 ECO #6 911.6 144.8 1,056.4 268.4 6.0 67.1 4.0
- 43. 1-18 Energy Audit of Building Systems: An Engineering Approach, Second Edition their analysis, Katipamula, Reddy, and Claridge found that wind and solar radiation have small effects on the energy consumption. They also found that internal gains have a generally modest impact on energy consumption. Katipamula, Reddy, and Claridge (1998) discuss in more detail the advantages and the limitations of multivariate regression modeling. 2. Time-Variant Models: There are several techniques that are proposed to include the effect of time variation of several independent variables on estimating the energy savings due to retrofits of building energy systems. Among these techniques are artificial neural networks (Krarti et al., 1998), Fourier series (Dhar, Reddy, and Claridge, 1998), and nonintrusive load monitoring (Shaw et al., 1998). These techniques are typically involved and require a high level of expertise and training. 1.7 Summary An energy audit of commercial and industrial buildings encompasses a wide variety of tasks and requires expertise in a number of areas to determine the best energy conservation measures suitable for an existing facility. This chapter provided a description of a general but systematic approach to performing energy audits. If followed carefully, the approach helps facilitate the process of analyzing a seemingly endless array of alternatives and complex interrelationships between building and energy system components.
- 44. 2-1 2.1 Introduction Energy cost is an important part of the economic viability of several energy conservation measures. Therefore, it is crucial that an energy auditor or building manager understand how energy costs are determined. Generally, a considerable number of utility rate structures do exist within the same geo- graphical location. Each utility rate structure may include several clauses and charges that sometimes make following the energy billing procedure a complicated task. The complexity of utility rate structures is becoming even more acute with the deregulation of the electric industry. However, with new electric utility rate structures (such as real-time-pricing rates), there can be more opportunities to reduce energy cost in buildings. At the beginning of this chapter, the primary energy sources consumed in the United States are described. The presentation emphasizes energy use and price by end-use sectors including resi- dential, commercial, and industrial applications. In the United States, buildings and industrial facilities are responsible for 36 and 38 percent, respectively, of the total energy consumption. The transportation sector, which accounts for the remaining 26 percent of the total U.S. energy con- sumption, uses mostly fuel products. However, buildings and industries predominantly consume electricity and natural gas. Coal is primarily used as an energy source for electricity generation due its low price. At the end of this chapter, the various features of utility rate structures available in the United States are outlined. More emphasis is given to the electrical rate structures because a significant part of the total energy cost in a typical facility is attributed to electricity. The price rate structures of other energy sources are discussed. The information provided in this chapter is based on recent surveys of existing utility rate structures. However, the auditor should be aware that most utilities revise their rates on a regular basis. If detailed information is required on the rates available from a specific utility, the auditor should contact the utility directly. 2.2 Energy Resources The sources of energy used in the United States include: coal, natural gas, petroleum products, and elec- tricity. The electricity can be generated from either power plants fueled from primary energy sources (i.e., coal, natural gas, or fuel oil) or from nuclear power plants or renewable energy sources (such as hydroelectric, geothermal, biomass, wind, photovoltaic, and solar thermal sources). In the United States, energy consumption has fluctuated in response to significant changes in oil prices, economic growth rates, and environmental concerns especially since the oil crisis of the early 2 Energy Sources and Utility Rate Structures
- 45. 2-2 Energy Audit of Building Systems: An Engineering Approach, Second Edition 1970s. For instance, U.S. energy consumption increased from 66 quadrillion British thermal units (Btu) in 1970 to 99 quadrillion Btu in 2008 (EIA, 2009). Table 2.1 summarizes the changes in U.S. energy consumption by source from 1972 to 2008. It is clear from the data summarized in Table 2.1 that the consumption of coal has increased signifi- cantly from 12 quadrillion Btu in 1972 to 22.5 quadrillion Btu in 2008. However, the U.S. consumption of natural gas actually declined from 22.5 quadrillion Btu in 1972 to 20.7 quadrillion in 1998 before increasingly slightly to 23.8 quadrillion Btu in 2008. This decline in natural gas consumption is due to uncertainties about supply and regulatory restrictions especially in the 1980s. Between 1972 and 2008, consumption of other energy sources generally increased. The increase is from 33.0 quadrillion Btu to 37.1 quadrillion Btu for petroleum products, from 0.6 quadrillion Btu to 8.5 quadrillion Btu for nuclear power, and from 4.5 quadrillion Btu to 7.3 quadrillion Btu for renewable energy which consists almost exclusively of hydroelectric power. Table 2.2 provides the average nominal energy prices for each primary fuel type. Over the years, coal remains the cheapest energy source. The cost of electricity is still high relative to the other fuel types. As illustrated in Table 2.2, the prices of all energy sources have increased significantly after the energy crisis of 1973. In particular, the cost of petroleum products has increased severalfold over the last few years. 2.2.1 Electricity 2.2.1.1 Overall Consumption and Price In the United States, coal is the fuel of choice for most existing electrical power plants as shown in Table 2.3. However, gas-fired power plants are expected to be more common in the future due to more efficient and reliable combustion turbines. Table 2.1 Annual U.S. Energy Consumption by Primary Energy Sources in Quadrillion Btu Primary Energy Source 1972 1982 1992 2002 2008a Coal 12.077 15.322 19.187 21.965 22.462 Natural gas 22.469 18.505 20.714 23.558 23.838 Petroleum products 32.947 30.232 33.527 38.809 37.137 Nuclear power 0.584 3.131 6.479 7.959 8.455 Renewable energy 4.478 6.293 6.707 5.894 7.300 Total 72.758 73.442 85.559 97.858 99.304 Source: EIA Annual Energy Review, Department of Energy, Energy Information Administration, http://www.doe.eia.gov, 2009. a The data for 2008 are preliminary data that may be revised. Table 2.2 Consumer Price Estimates for Energy in Nominal Values in U.S. $/Million Btu Primary Energy Source 1972 1982 1992 2002 2006 Coal 0.45 1.73 1.45 1.30 1.78 Natural Gas — 4.23 3.83 5.27 9.62 Petroleum Products 1.78 8.35 7.07 8.82 17.89 Electricity 5.54 18.16 20.06 21.15 26.15 Source: EIA Annual Energy Review, Department of Energy, Energy Information Administration, http://www.doe.eia.gov, 2009.
- 46. Energy Sources and Utility Rate Structures 2-3 The electricity sold by U.S. utilities has increased steadily for both the residential and commercial sectors as indicated by the data summarized in Table 2.4. The increase in electricity consumption could be even higher without the various energy conservation programs implemented by the federal or state governments and utilities. For instance, it is estimated that the demand-side-management (DSM) pro- grams provided by utilities have saved about 54 billion kWh in electrical energy use during 2002 and over 69 billion kWh in 2007 (EIA, 2009). The prices of electricity for all end-use sectors have remained stable between 1992 and 2008 after a recovery period from the 1973 energy crisis as illustrated in Table 2.5. As expected, industrial customers enjoyed the lowest electricity price over the years. Meanwhile, the cost of electricity for residential customers remained the highest. 2.2.1.2 Future of U.S. Electricity Generation Currently, the electricity market is in the midst of a restructuring period and is becoming increasingly competitive. Several innovative technologies are being considered and tested to generate electricity. A Table 2.3 Annual U.S. Electrical Energy Generated by Utilities by Primary Energy Sources in Billion kWh Primary Energy Source 1972 1982 1992 2002 2008a Coal 771 1,192 1,576 1,933 1994 Natural Gas 376 305 264 691 877 Petroleum Products 274 147 89 95 45 Nuclear Power 54 283 619 780 806 Renewable Energy 274 314 254 343 372 Total 1,749 2,241 2,797 3,859 4,110 Source: EIA Annual Energy Review, Department of Energy, Energy Information Adminis tration, http://www.doe.eia.gov, 2009. a The data for 2008 are preliminary data that may be revised. Table 2.4 Annual U.S. Electrical Energy Sold by Utilities by Sector in Billion kWh End-Use Sector 1972 1982 1992 2002 2008a Residential 539 730 936 1,265 1,379 Commercial 359 526 850 1,205 1,352 Industrial 641 745 973 990 982 Source: EIA Annual Energy Review, Department of Energy, Energy Information Admin is tration, http://www.doe.eia.gov, 2009. a The data for 2008 are preliminary data that may be revised. Table 2.5 Average Retail Prices of Electric Energy Sold by U.S. Utilities by Sector in 2000 Cents per kWh End-Use Sector 1972 1982 1992 2002 2008a Residential 7.9 11.0 9.5 8.1 9.3 Commercial 7.5 11.0 8.9 7.6 8.4 Industrial 4.1 8.0 5.6 4.7 5.7 Source: EIA Annual Energy Review, Department of Energy, Energy Information Administration, http://www.doe.eia.gov, 2009. a The data for 2008 are preliminary data that may be revised.
- 47. 2-4 Energy Audit of Building Systems: An Engineering Approach, Second Edition relatively recent approach to producing electricity using small and modular generators is the distrib- uted generation concept. The small generators with capacities in the range of 1 kW to 10 MW can be assembled and relocated in strategic locations (typically near customer sites) to improve power qual- ity and reliability, and provide flexibility to meet a wide range of customer and distribution system needs. A number of technologies have emerged in the last decade that allow the generation of electricity with reduced waste, cost, and environmental impact. It is expected that these emerging technologies will improve the viability of distribution generation in a competitive deregulated market. Among these tech- nologies are fuel cells, microturbines, combustion turbines, gas engines, and diesel engines. Chapter 13 discusses some of the emerging technologies in electricity generation. 2.2.1.3 Utility Deregulation Impact Following the acceptance of the Energy Policy Act of 1992, which requires open access to utility trans- mission lines, the U.S. Federal Energy Regulatory Commission (FERC) issued orders to allow the estab- lishment of a wholesale power market with independent system operators. As the result of a significant increase in the quantities of bulk power sales, delivery of energy to users has become increasingly difficult especially through the existing transmission and distribution networks. The frequent power outages experienced in the last few years, especially in the western United States, illustrate the precari- ous stability of the transmission system. Moreover, several states have started to implement retail access, which allows customers to choose among several electric service providers based on a competitive market that may offer a variety of customized services such as a premium power quality. Unfortunately, existing distribu- tion networks are not designed to support multiple suppliers or to channel value-added services. Ironically, utilities have built less than half the transmission capacity between 1990 and 1995 than they built in the previous five years (1985–1990). This reduction of investment in the transmission grid is largely due to the uncertainty about ongoing electric utility deregulation and restructuring (EPRI, 1999). In addition to adding new transmission capacity, it is believed that existing transmission and distri- bution networks and their control have to be upgraded using advanced and new technologies to ensure high reliability and safety of the power delivery system. Among the technologies that are being consid- ered to upgrade the power delivery system are the following: The discovery in 1986 of high-temperature superconducting (HTS) materials using ceramic oxides • has lowered the cost of superconducting transmission cables to a reasonable level. It is estimated that an HTS cable could carry 500 MW of electric power at voltages as low as 50 kV. High-voltage electronic flexible AC transmission system (FACTS) controllers are now used by • several utilities to increase the capacity of transmission lines and improve overall delivery system reliability. Unlike conventional electromechanical controllers, FACTS controllers are sufficiently fast to reduce bottlenecks and transient disturbances in power flow and thus reduce transmission system congestion and improve overall delivery reliability. Cost-effective distributed generation and storage technologies offer flexibility to meet a wide vari- • ety of customer needs. Among distribution generation systems under development and testing are microturbines with capacities ranging from 10 to 250 kW, and fuel cells that offer clean, effi- cient, compact, and modular generation units. Diversified and integrated utility services meet the divergent needs of various market segments. • For instance, innovative rate structures such as real-time-pricing rates are being offered to cus- tomers that are demanding lower rates. Moreover, some utilities are integrating electricity with other services such as Internet access, telecommunications, and cable television using fiber-optic networks. However, the move to integrate utility functions requires new hardware and software
- 48. Energy Sources and Utility Rate Structures 2-5 technologies. For instance, low-cost electronic meters with two-way communications are needed to provide real-time-pricing and billing options for multiple utility services. 2.2.2 Natural Gas As indicated in Table 2.6, the total U.S. consumption of natural gas actually declined between 1972 and 2008. The industrial sector experienced the highest reduction in natural gas use especially in the 1980s. The main reason for the decline in natural gas use is attributed to the restructuring and deregulation of several segments of the gas industry during most of the 1970s. Indeed, the regulation of natural gas markets had the effect of reducing the availability of natural gas. As indicated in Table 2.7, the prices of natural gas increased significantly between 2002 and 2008. During the 1990s, the prices of natural gas actually decreased because gas supplies became more certain and some of the regulations were removed. In the future, it is expected that the natural gas market will continue to expand and its pricing to be competitive. In particular, the future for natural gas as a primary energy source for electricity genera- tion is considered to be promising. Indeed, gas-fired power plants are competitive because of their high efficiencies (approaching 50 percent) and are environmentally attractive because they produce signifi- cantly lower carbon and sulfur emissions than plants powered by coal or oil. 2.2.3 Petroleum Products Overall, the U.S. consumption of fuel oil and other petroleum products has remained stable between 1972 and 2008 as indicated in Table 2.8. However, oil prices fluctuated significantly over the last three decades after the 1973 energy crisis. In the building sector (i.e., residential and commercial applica- tions), the U.S. consumption level of petroleum products has decreased over the years. However, the use of petroleum fuels has steadily increased in the transportation sector. Table 2.9 clearly indicates that after a drastic increase (almost fourfold) between 1972 and 1982, crude oil prices decreased in 1998 to levels even lower than those experienced in 1972. However, another sig- nificant increase in oil prices occurred between 2002 and 2008. Table 2.6 Annual U.S. Consumption of Natural Gas by Sector in Trillion Cubic Feet End-Use Sector 1972 1982 1992 2002 2008a Residential 5.13 4.63 4.69 4.90 4.87 Commercial 2.61 2.61 2.80 3.14 3.12 Industrial 9.62 6.94 8.70 8.62 7.94 Source: EIA Annual Energy Review, Department of Energy, Energy Information Administration, http://www.doe.eia.gov, 2009. a The data for 2008 are preliminary data that may be revised. Table 2.7 Average Retail Prices of Natural Gas by Sector in 2000 Dollars per 1,000 Cubic Feet End-Use Sector 1972 1982 1992 2002 2008a Residential 4.01 8.24 6.82 7.57 11.17 Commercial 2.92 7.68 5.65 6.36 9.79 Industrial 1.49 6.17 3.29 3.86 7.85 Source: EIA Annual Energy Review, Department of Energy, Energy Information Administration, http:// www.doe.eia.gov, 2009. a The data for 2008 are preliminary data that may be revised.
- 49. 2-6 Energy Audit of Building Systems: An Engineering Approach, Second Edition 2.2.4 Coal In the United States, coal is primarily used as an energy source for power generation by electric utilities as shown in Table 2.10. Indeed, the total U.S. consumption of coal increased between 1972 and 2008 due primarily to the growth in coal use by electric utilities. In all other sectors (i.e., residential, com- mercial, and industrial), coal consumption has decreased. These consumption trends are expected to be maintained in the near future for all sectors. However, the share of electricity generation attributed to coal will be reduced due to more reliance in the future on other generation technologies as discussed in Section 2.2.1. The abundant coal reserve base and the lingering excess production capacity have helped maintain low coal prices especially during the last decade as indicated by Table 2.11. In the future, however, the price of coal is expected to rise slowly due to reserve depletion and slow growth in labor productivity. The higher coal prices coupled with environmental concerns may cause a future decline of coal con- sumption in the United States. Table 2.8 U.S. Consumption of Petroleum Products by Sector in Million Barrels per Day End-Use Sector 1972 1982 1992 2002 2008a Residential/commercial 2.25 1.24 1.19 1.20 0.98 Industrial 4.19 4.06 4.52 4.93 4.58 Transportation 8.57 9.31 10.88 13.21 13.65 Electric utilities 1.36 0.69 0.43 0.43 0.21 Total 16.37 15.30 17.03 19.77 19.42 Source: EIA Annual Energy Review, Department of Energy, Energy Information Administration, http://www.doe.eia.gov, 2009. a The data for 2008 are preliminary data that may be revised. Table 2.9 Average Crude Oil Price in the United States in 2000 Dollars per Barrel Year 1972 1982 1992 2002 2008a Price 11.24 45.47 18.51 21.61 76.82 Source: EIA Annual Energy Review, Department of Energy, Energy Information Administration, http://www.doe.eia.gov, 2009. a The data for 2008 are preliminary data that may be revised. Table 2.10 Annual U.S. Consumption of Coal by Sector in Million of Short Tons End-Use Sector 1972 1982 1992 2002 2008a Residential/commercial 11.7 8.2 6.2 4.4 3.6 Industrial 160.1 103.0 106.4 84.4 76.6 Electric utilities 351.8 593.7 795.1 977.5 1,041.6 Total 524.3 706.9 907.7 1,066.4 1,121.7 Source: EIA Annual Energy Review, Department of Energy, Energy Information Administration, http://www.doe.eia.gov, 2009. a The data for 2008 are preliminary data that may be revised. Table 2.11 Average Coal Price in the United States in 2000 Dollars per Short Ton Year 1972 1982 1992 2002 2008a Price 25.59 43.44 24.34 17.26 26.62 Source: EIA Annual Energy Review, Department of Energy, Energy Information Administration, http://www.doe.eia.gov, 2009. a The data for 2008 are preliminary data that may be revised.
- 50. Other documents randomly have different content
- 51. “I thought one of them was quite smitten with Daisy.” “So he seemed, but I guess he was ashamed of himself.” Reluctantly John decided to go; Marjorie needed the rest. “Marjorie, I am leaving your Christmas present with your mother, since I won’t see you on Christmas. And may I come up the day after?” “That’s the luncheon.” “Well, I want to hear all about it.” “I thought maybe I’d stay over night at Lil’s.” “Then let me come there—Lily will have Dick, and you know that ‘three’s a crowd.’” “Right, John! You’ll be more than welcome.” Almost wistfully Marjorie watched him go; she had enjoyed the evening even more than she would admit to herself. She took her flowers, absently pressing them to her lips, and half closed her eyes dreamily. After all, Girl Scouts were not the only thing in the world. The next day she felt less tired, less depressed by the invisible weight she had seemed to be carrying, and by Christmas her old spirits had returned, she was quite herself again. John’s present turned out to be books; knowing her taste he had selected just what she liked best, yet in her heart she was a trifle disappointed. Why couldn’t it have been jewelry—not a ring, of course, but a pin, perhaps—it would have been so much more personal. Yet she knew that she had said nothing to tempt him to risk taking such a liberty, and she could not but admire him for his tact. Her strength was so restored by the rest and quiet of the last few days that she decided to drive to New York in her car. Daisy and Florence would undoubtedly bring theirs, and perhaps Alice; it would be fun to display them together to Mae and Doris. The weather was cold, but clear, and the roads were hard and dry. Wrapped snugly in her fur coat, she felt that the drive would be exhilarating; she jumped into her car with as keen a sense of anticipation as if it had been May instead of December. She did not regret in the least the fact that she was to go alone; her own
- 52. thoughts would be as pleasant company as she could desire. At that moment Marjorie Wilkinson was perfectly happy. She found four cars exactly alike parked in front of Lily’s apartment house, and for a second she wondered whether Ethel could have scorned the distance and driven all the way from school in hers. An instant later, however, she recognized Lily’s licence number, and laughed at her roommate’s evident desire to be represented in the display. Lily was prouder of her little roadster than she had ever been of her Rolls-Royce. She found four of the girls—Daisy, Alice, Ethel and Florence in a circle about Lily, admiring her engagement ring—a solitaire in a filigree platinum setting. Lily had discarded her other rings for the time being, so the new jewel shone out in undisputed splendor on her pretty hand. “We’re not a bit surprised,” said Alice teasingly. “We’ve known it for a long time!” Lily turned indignantly towards her roommate. “Marj!” she flared. “If you told on me——” For a moment Marjorie looked hurt; then Lily burst out laughing. “I know you didn’t, you old peach!” she declared. “But I guess after all I couldn’t expect it to be much of a secret. Girls, where do you suppose Doris and Mae are?” “Coming now!” cried Ethel, rushing into the hall as the butler opened the door. Lily’s engagement was forgotten; everything, everybody faded into the background at the entrance of the young mother with her baby. Little Doris was four months old now, and they all pronounced her the very cunningest baby they had ever seen. She was not in the least frightened by the girls, but went from one to another of her admirers with the sweetest smile. “Our youngest Girl Scout!” Alice nicknamed her as she dropped on her knees to play with her. “It was so thoughtful of you to have a girl, Doris.” Doris beamed in happiness, and her daughter imitated her with a smile.
- 53. “Who’ll hold her during luncheon?” asked Marjorie eager for her turn to come. “No one, of course!” answered the mother sternly. “Well brought- up babies aren’t held during meals. They lie on a bed with their bottles.” “Oh,” replied Marjorie humbly, “I guess I don’t know much.” “You couldn’t know less than I did,” Doris assured her. “But it’s very easy to learn—it sort of comes natural.” She carried the baby into one of the bedrooms and the girls answered the summons to luncheon. Although the table was elaborately decorated, and the courses beautifully served, Lily explained that she had not planned any special feature to announce her engagement in a novel way, “because,” she concluded, “it has to be a complete surprise to pull off a stunt like that.” “And yours wasn’t,” added Ethel. “I supposed it was a fact ever since last summer, but when I visited you that Sunday I was positive of it.” “And I knew it all along, too!” Alice boasted. “Well,” returned Lily, “since you’re all such clever guessers, tell me which girl in the patrol is engaged—besides me!” The girls all opened their eyes wide in interest and stopped eating to look around the group and study the expressions of the others. No one, apparently, betrayed any guilt. “Who?” demanded Alice excitedly. “Tell us quick, Lil!” Her hostess laughed softly. “Oh, you’re so wise that I don’t have to tell you!” “Well, let’s figure it out,” began Ethel. “Doris and Mae are married —you’re not either of you contemplating a divorce, are you?” Both girls shook their heads emphatically. “Lily has announced her engagement, and I know I’m not the one. That leaves Daisy, Floss, Alice and Marj.” “It’s Marj, of course!” cried Alice. Marjorie smiled enigmatically; it would be fun to tease them. “Are you the one, Marj?” Alice persisted.
- 54. “She is!” exclaimed Daisy. “Look how guilty she looks!” “No, girls, she isn’t,” Lily answered for her. “I give you my scout word of honor, unless something has happened since we left college. But I won’t hold you in suspense any more: I was only teasing you!” “Then nobody is?” Alice inferred, a trifle disappointed. “Goodness, isn’t one engagement enough for you in one day?” asked Ethel. “Aren’t you really keeping anything from us, Marj?” Alice repeated. “No,” laughed Marjorie. “Absolutely nothing. I have taken a solemn vow not even to think of marriage until I get my Girl Scout troop firmly established.” “Good gracious, Marj! You’ll never get them ‘established,’ as you say!” remarked Florence. “If you succeed in holding them together for a whole week after the basketball season is over, I’ll treat you to a dinner at the Ritz!” “Thanks,” replied Marjorie confidently. “Better start to save your money. And, to go back to the old subject, I mean to train for more scout work. I’m going to take a six weeks’ course at the national Leaders’ Camp this summer and hope to land a job next year.” “Poor John!” muttered Daisy. “Marj has had too much attention at this luncheon,” Ethel abruptly announced. “We must concentrate on the bride-to-be. Tell us about your plans, Lil.” “Well, we expect to live in Philadelphia,” replied the latter, “for Dick is permanently located there. We hope to get a house somewhere near Doris and Roger.” “And when are you going to be married?” “In June—after graduation.” “Think of getting an A.B. and a MRS. both in one month!” remarked Daisy, almost enviously, it seemed. “It will be lovely to have you in Philadelphia,” Doris assured her. “Wouldn’t it be grand if all eight of us were married and lived near together!” “You are domestic, Doris!” teased Ethel.
- 55. “Girls, that reminds me,” put in Lily, “I invited Mrs. Remington to this luncheon, but she couldn’t come. So she sent her love, and asked that we start a round-robin, to keep us informed with what everybody is doing.” “Great idea!” approved Ethel, who was least in touch with the others. “I’ll start it this very week.” A gentle coo from the baby in the adjoining room drew them away from their coffee cups, and the remainder of the afternoon was spent in admiration of Lily’s hope-chest, and little Doris Harris.
- 56. CHAPTER XVIII. DOLLS. The luncheon guests had all gone home; Marjorie and Lily were resting before dinner. Neither, however, seemed inclined to sleep; both were occupied with their own thoughts. “Marj,” began Lily, dreamily, after she had reassured herself that her companion was awake, “would you care an awful lot if I didn’t come to scout meeting every Saturday night?” The other girl regarded her tenderly. “Of course not, Lil—I understand. You have so much to plan for to think about, if you’re going to be married right after Commencement. I know I’d feel the same way.” “You won’t think me a quitter, then?” she asked, anxiously. “It isn’t as if I weren’t interested in the troop—but I’m so sure it’s going to keep on going splendidly that I don’t believe you really need me. Sophia can take my place on the team. If it were any other night but Saturday——” “Yes, of course, Lil,” repeated Marjorie sympathetically. “I really think you are right. After all, Dick has some claims. And he ought to have your week-ends.” “I’m so glad you see it that way, Marj! I do want to come home, too, whenever I can, for mother and dad’s sake as much as for my own. She even insists on a New York dressmaker for my trousseau, though I’d rather just find somebody in Philadelphia. You know I haven’t any classes on Saturday, so I could leave college sometimes on Fridays.” “The scouts will agree, I am sure,” continued Marjorie, “especially when they see your ring. They won’t think it’s because you’re tired of them.”
- 57. “Do you think that you ought to get another lieutenant?” Lily inquired. “Daisy or Floss?” “All three of the juniors are busy with that troop in the village,” Marjorie reminded her. “So I’d hate to take them away, for they’re doing good work there. And I’m sure I don’t want an outsider. No, I think I can manage myself, if you’ll drop in whenever you can.” “Indeed I will!” the other girl promised. Marjorie closed her eyes and tried to sleep, but she found it impossible. Although up to this time she had been quite successful in dismissing her scout troop from her mind during the vacation, she found her old perplexing problems returning. It was Florence who had stirred up this questioning, Florence who had suggested that she did not have a firm hold on the troop, that they would be interested only as long as the basketball season lasted. When the girls began to dress for dinner, she sought Lily’s advice. “I don’t want to bother you, Lil, but I must talk scout affairs over with you once in a while. Floss’ remark that the girls are only interested in basket-ball sort of worries me. Couldn’t you suggest some new interest, like you did this one?” Her chum, who at that moment was trying to decide whether to wear a heliotrope georgette or a black velvet dinner dress, brought her attention with difficulty to Marjorie’s question. “What—er—yes,” she answered absently. “Think of something, Lil!” Marjorie pleaded. Lily looked at her companion in amusement. “I think, Marj, for your own sake, you ought to forget that troop for a while. You promised you would during the holidays, you know. And everything’s going beautifully—remember the game, and our boxes of chocolates!” “I know—but who was it who said, ‘In time of peace prepare for war?’ That’s my idea—just keep things going every minute, so that the girls haven’t time to wonder whether they are bored.” “But my dear, you can’t expect this to keep up all your life! You probably wouldn’t have time for them next year, anyway.”
- 58. “All the more reason why I must make a desperate attempt to secure a really firm hold, so I could be as sure of them as I am of our senior patrol.” “You’ll never be able to do that, Marj. That would be almost a miracle. But I do think you’ve done remarkably; why not be content?” “Oh, I can’t! If that is all, then I shall have failed!” “Better fail, as you call it, than give your life to such a tremendous struggle. Marj, do be normal! Just enjoy things while you’re young! Don’t be everlastingly aiming at the impossible.” Marjorie laughed, but it was without heart. There was no use appealing to Lily now, indeed she ought to be thankful that her roommate had already given her so much assistance. She knew that she had made the same promise to John—not to refer to the troop during the vacation—yet she decided to risk breaking it. If there was a possibility of his helping her, he would not want her to worry over her problem alone. So, as soon as the young men had arrived, and had heard all the details of the luncheon, and John had presented his best wishes to the couple, Marjorie sought an opportunity to talk with him in confidence. As she had hoped, she found him eager to listen. “I have been expecting this—though I didn’t think you would see it until nearer the close of the basketball season,” he said quietly. “And I have been doing some thinking along lines of my own. I have a suggestion to offer, although you may not consider it very good. Don’t hesitate to tell me if you don’t approve.” “Oh, thank you, John!” cried the girl, with a feeling of deep gratitude in her heart. “Well, one day last week our wash-woman’s little girl was run over and was taken to the Children’s Hospital. She is getting along all right, fortunately, but Mother wanted me to go see her and take her some flowers and fruit. I found her in the children’s ward—the most pathetic, and yet the most marvellous place in the world.” “Yes?” breathed Marjorie sympathetically.
- 59. “I just wish you could have seen the brave little patients there, some of them the most dreadful cases, but all trying to be so courageous. I admit I could scarcely keep back my tears, and when I got home and told Mother all about it, she had a good cry. I don’t think I ever have been more deeply touched. “I felt as if I must do something—send more money, more toys, more nurses. I wanted to go out and preach children’s hospitals from morning till night, I wanted to get every girl I knew to enroll as a nurse. If you could see the way the little things depend upon those nurses! They adore them, they wait patiently till they have time to attend to them. Oh, they are wonderful!” Marjorie herself felt near to tears, so realistic was John’s description of the little sufferers. She did not trust herself to say anything. “And then I thought of your girl scouts, girls who have no definite aim in life, who are not preparing for anything special, and I wondered whether we couldn’t turn at least part of their interest there. Perhaps we have been thinking too much of what we could do for them; maybe if we realized that the greatest thing would be for them to do something for others, we might succeed further.” “I believe you’re right, John,” Marjorie said, thoughtfully. “But how?” “Well, I would begin by taking them to see the children. There are about fifteen little girls in that ward; suppose I bought a doll for each child—would your girls dress them? That would give them a chance to see the hospital from the inside, and they might be interested. You may even be able to start a course in home-nursing or first-aid, as a result.” Marjorie was silent for a long while, pondering the idea. Was it possible, she wondered, to touch these girls, to take them outside of themselves and their own little worlds, to see someone else’s point of view? Was not John correct in thinking she had given too much attention to the good she might do them, rather than the good they might do to others? The idea was so much bigger than any she had
- 60. ever conceived for them that she was almost terrified at its seriousness. “It certainly is worth a try, John. It would be great if we could interest them, but I am not going to count on it, or expect a miracle. At least the visit to the hospital with the dolls would be worth-while, if nothing finally came of it.” “Then you will let me send the dolls?” “I’d love to—but you better wait till I ask the scouts. There is a chance they may turn me down.” “But you do like the suggestion?” “Immensely, John—and—thank you so much.” She lowered her voice almost to a whisper. “Other people may fail me in emergencies, but it seems to me you are always there.” Nor did Marjorie’s words express the real depth to which she was touched. If this scheme worked, she might be able to reach the girls whom she still felt to be outside of her influence. About Stella and Annie she was no longer concerned; they not only took basketball seriously, but athletics had really opened up a new life for them. They had told her that they were going regularly to the Y. W. C. A. for swimming instruction; their nights were so crowded now that there was little time for frivolity. Moreover, both girls were enlarging their circles of friends to include those more interested in the real things in life. It was almost as if they had received a fresh start; she felt satisfied that they would no longer drift. She next thought of the school girls—Dot Williams and the twins; they were apparently headed in the right direction; but what about Queenie and Clara and Aggie? Of all the patrol these were the most pleasure-loving, the most flighty, and, with the exception of Queenie, the most irresponsible. Could she possibly hope to interest them in charitable work of any kind? Would they turn in disgust from contact with suffering in any form? Perhaps they might be bored by it, but at least they could not ridicule it. Only someone less than a human being could fail to be affected by a sight so pathetic as the one John had described.
- 61. The remainder of Marjorie’s vacation passed all too quickly; there were shopping expeditions, rides with her mother in her own little car, evenings with John at home. Almost before she realized it, she was back at college, sharing in pleasant little celebrations in her roommate’s honor. She could not fight off an intangible sense of loneliness as she drove into the city to her first scout meeting of the new year. It was not so much that she missed Lily on this one particular occasion, but that she felt it to be symbolic of her days to come. In the eight years of her school life away from home, no one had been so close to her as this girl. At last she was to be separated from her; she sighed, but she would not alter the situation if she could. It was lovely for Lily to be so happy. Her spirits rose, however, as she drew up to the settlement and found Queenie and Stella waiting for her just inside the door. Regardless of the fact that they wore neither hats nor coats, they both rushed out in the cold to greet her. “You didn’t elope, then, did you, Miss Wilkinson?” demanded Queenie. “We were almost afraid you’d give us the slip!” “Nothing like that, Queenie,” Marjorie replied laughingly. “How about you?” “Her sweetie’s out of town,” Stella answered for her. “Slipped off without even coming across with a Christmas present.” Inwardly Marjorie breathed a sigh of thanksgiving. She hoped fervently that “Sam” was gone for good. All the rest of the troop were already assembled in the scout room, and Marjorie felt something of the joyousness of homecoming in her welcome. There was no doubt about their genuine pleasure in her return. She felt hopeful about launching her new plans. The girls, however, were eager to talk of basket-ball; they wanted to hear Marjorie’s opinion of the match game, and Jack’s; they demanded the rest of their League schedule, and they insisted upon discussing their opponents. “The whole thing is arranged very fortunately for us,” remarked Marjorie. “We have two easy teams to play next—at least I hope
- 62. they’ll be easy—from Troop Thirty-five, and Troop Eighteen. Then in February we meet Troop Six, and the very last League game of the season is our team against One-Sixty One!” “Hooray!” shouted Queenie gleefully. “Lady Luck sure is with us! Remember I said we’d whitewash Sixteen and Thirty-five? Well, there’s no doubt about it now, after we trimmed Ninety-seven so neat!” “I have one sad piece of news for our troop, though,” interrupted Marjorie: “Miss Andrews has announced her engagement to Mr. Roberts, and feels that she hasn’t time enough to play on our team any longer. She wants to be with her fiancé on Saturday evenings.” “Good night!” cried Stella in dismay. “What did she have to go and get engaged for—just when our team was pullin’ together so good!” “Anyway we can be glad it ain’t—isn’t—you, Miss Wilkinson!” observed Queenie. “Or you!” returned Marjorie meaningly. “And it’s a good thing we got Sophia. But say, we’ve got a get another sub. Any of you kids done any work over Christmas?” All three of the tenderfoot scouts shook their heads guiltily. “Let’s make it a race,” suggested Marjorie, “and see who can be ready first. I’ll telephone Mr. Richards.” “That’ll fix ’em—they’ll get to work!” Queenie assured her jokingly. “Specially Goldie—she’s entirely gone on him.” Reluctantly Marjorie put aside the subject of basketball and steeled herself to put forward her new proposition. “Girls,” she began, “would you be willing to dress some dolls for some children in a hospital ward?” “I can’t sew!” announced Annie Marshall immediately. “And I hate it!” volunteered Aggie. Marjorie’s spirits fell. But remembering the hike, she decided not to insist. “All right, then—that’s all about that,” she said as cheerfully as she could.
- 63. But when the girls were adjourning their meeting to the basketball floor, she was surprised to hear Goldie and Dot bring the subject up again. “Miss Wilkinson,” whispered Dot, “Goldie and I would love to dress some dolls for sick children. Will you tell us about it?” Marjorie’s heart warmed towards these girls—almost children themselves in comparison to herself. She told them gladly of her idea —that the troop dress some and take them to the hospital in person. “Bring them next week!” Goldie pleaded, “and we’ll make all the others envious. Just you watch!” Marjorie was only too delighted to promise that she would. Her one regret was that it was not Queenie who offered.
- 64. CHAPTER XIX. THE EXHIBITION. Marjorie did not bring the dolls to the next scout meeting as she had promised, for it was a scheduled game with Troop Eighteen. She knew that the girls who had offered to dress them would be too excited to think about it. She was correct; for both Dot and Goldie were already on the floor practicing when she arrived. She sauntered over towards them. “Goldie,” she began, “how would you like to play this game instead of me?” The girl fairly gasped in amazement. “Oh, I never could, Miss Wilkinson!” “Why not? You passed your second-class test on Wednesday night, and you are registered with the League.” “You don’t get me, Captain. I’m not a good enough player, and besides, I couldn’t jump center. I’m not tall enough.” “Oh, that’s all right,” Marjorie assured her. “You would play forward, as you have been practicing. Queenie would jump; you know Jack has been training her to substitute that position.” Goldie’s eyes sparkled; there was nothing she would like better. “But what would your brother say?” “It was he who suggested it.” “Then it’s up to you. You’re the captain!” “Very well, then, you play forward with Annie. Queenie and Dot will take care of the center, and your sister and Stella can guard. I think a line-up like that can give any team a good fight.” Nor was she mistaken in her confidence; the girls, who now played with more assurance and less nervousness because of their recent victory, went into the game with all their energy, again trying
- 65. to follow their coach’s instructions to the letter. This time there was no confusion, no foul play; the opposing troop played a clean game, but Troop Two Hundred carried off the honors because of their superior skill. Marjorie felt elated; all the more so because the girls had been able to accomplish it unaided by officers. It was after the game was over, when they were together in the dressing room that Goldie suddenly thought of the dolls, and asked her captain whether she had brought them. “No,” replied Marjorie, “for two reasons. First, I didn’t think that tonight would be a good time to distribute them, on account of carrying them home, but principally because there are fifteen little girls in the ward, and I wouldn’t want to take them for some and not for all. And you and Dot and I couldn’t possibly dress five dolls apiece.” “Oh, I’ll help!” cried Sophia, who was in the mood to agree to anything anyone asked. “We’ll all do it, Miss Wilkinson,” muttered Queenie, not too pleasantly. “Not unless you really want to,” Marjorie stipulated. “All right, we want to, then. Bring ’em next week.” As soon as Marjorie was with John again, she told him of their expressions of willingness, which, she had to admit, seemed rather reluctant. “All right—I didn’t expect they’d enthuse over sewing. Most girls don’t. Look at the jokes in the paper about the married men who have to sew their own buttons on!” “I never cared for it much myself,” remarked Marjorie. “Trying to scare me?” he inquired jokingly, but was rewarded with a withering look. “I had no idea that they would be interested,” he continued, “until they actually pay a visit to the hospital. Only, by the way—mother had a suggestion to offer. She wants to supply the goods—what do you call ’em?—remnants?—and lace and ribbons to make the dresses, and said she’d be glad to offer a prize—a handbag, or something—to the girl who dresses the prettiest one.”
- 66. “That’s a great idea, John!” exclaimed Marjorie. “My word, you are a help to our troop!” “As much as Mr. Richards?” he asked slyly. “Almost,” Marjorie conceded. At the very next meeting she made an opportunity to put his plans into action and found them more successful then she had dared to hope. The dolls were little French toys; their pretty faces made a decided appeal to all of the girls. Moreover, the materials which Mrs. Hadley had sent were so dainty and charming, that it made them actually want to sew. While they were thus busily engaged, talking at the same time about the prize that was offered, Mr. Richards dropped in. “No interest in second-class tests tonight, I can see that!” he joked in his pleasant, breezy manner, which was so attractive to the girls. “I guess this is no place for a mere man!” “Then we’ll quit!” announced Queenie, glad in her heart of an excuse to stop. “We can practice signalling——” The scout master raised his hand forbiddingly. “Nothing doing!” he asserted. “When I get married I want a girl who can sew—it’s lots more use than being able to signal. And I guess all the other fellows are about alike. So you go right on!” He addressed the troop in general, but he was looking at Marjorie. “He’s crazy about her!” Queenie thought, watching him jealously. “Of course, he couldn’t see me—when she’s around.” Her eyes narrowed. “What do I care?” she decided, with an unconscious toss of her head. “Didn’t I get a letter from Sam this morning?” She put her hand against her dress and distinguished the outline of the envelope against her clothing. “We’re all working for a prize,” Marjorie was telling Mr. Richards. Then she repeated the story of the children in the hospital, and mentioned the scouts’ proposed visit. The young man was more than interested, and asked that he be allowed to accompany them on their expedition. “Plannin’ to see her oftener,” Queenie mused with tightened lips.
- 67. “And that reminds me,” he continued, when he had been assured by the captain that he was welcome, “how would you girls like to study first-aid and follow it with home nursing? I could give you the first-aid, and I know a cracker-jack of a nurse who’d give the other.” Queenie knew that this time he kept his eyes fixed upon her, expecting her to accept with enthusiasm. Just to baffle him, she turned to Marjorie. “What do you say, Captain?” “Splendid!” cried Marjorie eagerly. “I think so, too!” put in Stella, not waiting to be asked. “All in favor say, ‘Aye,’” suggested Mr. Richards. “Aye!” voted every scout present. “All right, then, that’s settled—Miss Wilkinson can let me know when you want to begin. Now I won’t bother you any more. But tell me the date of the doll exhibition, so I can be on hand. I’d like to bring a bunch of flowers to the mother of the doll-baby I like best.” Queenie felt a sudden thrill pass through her. How wonderful it would be to wear a gift from him! Then she glanced at her own sewing and realized that her doll would never win a prize. Unless perhaps he might have a personal interest in her, and would identify her doll, and give her the flowers simply as a gift, in that guise. That possibility buoyed her up; she resolved not to answer Sam’s letter until after the exhibition, for, after all, the latter could not compare in any way with Mr. Richards. The scout master’s share in the affair seemed to give it an added attraction, for after his visit the girls worked willingly, stopping only when it was time for basketball practice. Only twice was the sewing excluded, on the occasions of the two League games, and as these both resulted in victories for their team, they did not feel that they had been robbing their basketball time. About the middle of March, just one week before the final deciding game of the League, they gave their little exhibition. As John had originally planned, there were fifteen dolls in all. Most of the girls had dressed two; Queenie and Aggie and Annie had been
- 68. satisfied with one. They arranged them to advantage in Miss Winthrop’s office, and awaited their guests. Only a small number had been invited—Mrs. Hadley and John, Mr. Richards, Jack, Lily and Miss Winthrop. They were to vote by ballot for their favorite, and the prize was to be awarded to the girl who received the most votes. Mr. Richards, however, reserved the right to control the sole vote upon his own prize. Queenie, who entertained no hope of winning Mrs. Hadley’s prize, watched Mr. Richards furtively as he strolled from doll to doll, picking them up now and then, apparently inspecting them carefully. She actually trembled when she recognized her own doll in his hand. The balloting was concluded; Marjorie collected the votes and counted them, while the girls busied themselves by serving the lemonade and cakes they had provided in honor of their guests. In a few moments the captain returned, a bright smile on her face. It was evident that she was well satisfied with the result of the election. She went over to the table and selected the winning dolls, holding them up for the others to see. With a gasp Queenie realized that hers had not been chosen! “Mrs. Hadley’s prize—the first prize—goes to this cute little doll in pink,” she announced—“which was dressed by Dot Williams. And the second prize goes to the baby doll, whose clothing was made by Goldie Ernsberg.” Every one but Queenie clapped approvingly; she sat silent, lost in remorse. Then suddenly realizing that her attitude might be noticed, she added her applause to the rest. But when the party met to pay their proposed visit to the children’s ward, Marjorie found, to her amazement and dismay, that Queenie Brazier was not among them. Nor could any member of the troop explain the cause of her absence.
- 69. CHAPTER XX. THE CHAMPIONSHIP. Although Marjorie had been disappointed in Queenie’s failure to participate in the troop’s visit to the hospital, she was not deeply concerned. Of all the girls in the patrol she had shown the least interest in the event; from the beginning she had tried to discourage it. Her doll had been the most carelessly dressed in the exhibition, and she had left almost immediately after the affair itself was over. But Marjorie felt so sure of Queenie that this indifference scarcely troubled her; it was enough to find the others so enthusiastic. Moreover she had not the slightest doubt that Sam MacDonald had passed out of Queenie’s life, so she dismissed the matter from her mind, believing that her absence had been due to a whim. After all she could not be expected to go in for everything. She wished, however, that she might hear from her before Saturday—the night of the big basket-ball game that was to decide the League championship. She wanted every one of her players to be on hand, in trim for her position, and she was counting on Queenie to jump center. It would be a wonderful honor for her troop if the team would win; it would give them a standing among the other troops in the city that no other one act could accomplish so quickly; it would go a long way in establishing them for next year. But Marjorie was well aware that victory was very doubtful; like themselves, Troop One Sixty-one had beaten every team that they had met thus far in the League, but in almost every instance by a greater advantage. She had watched some of their games, and had admired the dexterity of their players. Her one hope lay in Jack’s ability as a coach; he, too, had observed them keenly, and had trained his own team to cope with their tactics.
- 70. Marjorie herself would have been glad to play on the team if she had felt that she was needed. But during the last few weeks, she had experienced an increasing sense of fatigue, a decided reduction in energy. Always, she remembered, she had felt a certain weariness of both mind and body as the spring holiday approached, but this year she noticed it to a marked degree. John had perceived it, and had urged her not to play on the team if any one else were available; Lily had remarked about it, even to the extent of begging her to take a week-end off and go home. But she had steadfastly refused to let down; she was confident that she could stick it out to the end. The evening of the game arrived, and she drove into the city with Lily. Both girls were keyed to the highest pitch of excitement and anticipation. “I wish you wouldn’t even take your basketball suit,” Lily remarked, as they stepped into the car. “Because if your team is losing, you may be tempted to play.” “I shall leave it entirely up to Jack,” her companion replied. “If he advises me to play, I’ll do it.” “Well, I’ll take good care to see him and tell him how you’ve been feeling lately! I’ll fix you!” “Don’t be mean, Lil!” “It’s for your own good.” “We must think of the good of the team tonight—after this match is over, I’ll have all the rest of my life to consider my own good.” “Much chance!” muttered Lily sarcastically. “Well, I don’t honestly think you need worry,” Marjorie assured her. “It’s Queenie who has been practicing with the team, Queenie who has been coached on the signals—she’s the one Jack is depending on.” “I’m mighty glad of it!” replied the other, letting out her throttle, and giving her attention to the road, as if the matter were concluded. When the girls reached the hall where the game was to be played, they found it brilliantly lighted in honor of the occasion. From the
- 71. wide open windows a confusion of laughter and talking floated out; scouts and other visitors could be seen in all the front rooms of the building. It was evident that this was to be a big event for the Girl Scouts of Philadelphia. Marjorie and Lily found Dick and John waiting for them at the entrance, and made their way through the crowd to the gymnasium. There they saw not only bright lights, but festive decorations as well. The balcony had been divided into two sections; one of which was draped with wide streamers of yellow cheesecloth, with a huge artificial sunflower in the center, the other in blue, with a big cornflower ornamenting it. It was evident that the visitors were expected to express their preference for either team by sitting in the seats marked by their respective flowers. “Why, we have a splendid showing!” cried Marjorie gaily, as she looked up and saw half of their section already filled with spectators. “Look, Lil—we have more rooters than the other troop! Do you really suppose we’re so popular?” “Looks that way!” returned Lily, as much pleased as Marjorie. “But why, I wonder—when hardly anybody knows us?” “I think we must have won a lot of friends that first night when you made the girls stick to their principle. Everybody admires good sportsmanship.” “Well, it’s lovely, anyhow, whatever the reason is. But it means that you people better hurry up and get some seats, or there won’t be any left. Save a place for me, and I’ll be up as soon as I find Jack and get the team lined up.” Hardly was she outside the door when Goldie and Dot, obviously in a panic, literally bumped into her. “Captain!” Dot flung out breathlessly. “Queenie hasn’t shown up!” Marjorie grasped the excited girl’s arm in sudden alarm. “Queenie!” she repeated. Then, realizing that she must not allow the girls to lose control of themselves at so decisive a time, she added, “But it’s only ten minutes of eight. She’ll surely come—she always does.” “But she didn’t go to the hospital with us,” Goldie reminded her.
- 72. “Oh, that was different! That wasn’t basket-ball!” “But suppose she doesn’t come?” demanded Goldie. “What shall we do?” “Why, I’ll play, of course. The others are all here, aren’t they?” “Yes, but that leaves us without a single sub. Suppose something happens—five personal fouls on a player, or somebody gets knocked out——” “We shan’t worry about that till the time comes,” replied Marjorie coolly. “Let’s go into the dressing room, while I get ready. Above all, girls, don’t lose your nerve. We must win tonight!” They found the other members of the team—Stella, Annie and Sophia gathered together on one of the low benches in a corner of the room, talking with the same nervous rapidity as the others had displayed. Marjorie immediately set about her task of reassuring them; in a few minutes she had restored their natural good spirits. Yet for all her own words to the contrary, she was actually alarmed herself at the event which in her heart she believed would prove a catastrophe, not so much for the team, as for the troop. If she put forth a tremendous effort by sacrificing herself, she could probably play as good a game that night as Queenie, for what she lacked in energy, she would offset by superior knowledge and experience. But the effect upon the troop in general would be far more disastrous; if, as she now really believed, Queenie had lost interest in the scouts, the patrol would be without a leader, the girls would be at loose ends. Eight o’clock struck and both teams assembled on the floor to “warm up.” A reassuring cheer from the balcony greeted their own arrival, and caused the girls to glance up with pride at their well- filled section of the balcony. Marjorie caught Lily’s eye, gazing at her in questioning disapproval, but she only nodded and smiled as if nothing had happened. Mr. Richards slipped into the seat that John had saved for her, and waved to her in encouragement. The whistle blew, the captains shook hands, the players fell into their places. A sudden silence took possession of the spectators as the referee tossed the ball into the air.
- 73. Tense with determination, Marjorie jumped high into the air; but perhaps because she was out of practice, or possibly because she was so tired, she had not timed her jump with the accuracy of her opponent. The other girl was too quick for her; she tapped the ball back to her side-center, who, with the agility of a tigress, had slipped it into the right position, caught it, and tossed it over to her forward. Marjorie cast a desperate appeal to her guards, hoping that they would intercept the pass. Perhaps they might have succeeded, if Cornflower Troop had not done the unexpected. Instead of the forward’s passing it to her companion under the basket, who was well covered by Stella, she slipped it back to the side-center, got free herself again, and almost too quickly for the spectators to follow, received it back and shot for the goal. The ball dropped neatly through the basket, scoring two points in Troop One Hundred Sixty- one’s favor. Marjorie did not trust herself to look at her players during the applause which followed, but added her own expression of appreciation to that of the others. The trouble was entirely with her, she believed; if she could only succeed in getting the jump, everything would be different. But she was no more fortunate the second time than the first, and the ball took the same course down the floor. Its progress, however, was halted this time by Sophia; with almost a superhuman effort she jumped high into the air and intercepted the pass before the forward could secure the ball. Instantly both Marjorie and Dot got free; Sophia chose Dot as her recipient, the latter sent the ball straight into Stella’s hands. “Now for a goal!” thought Marjorie, her heart beating wildly. “Oh, if it only does go in——” But Stella’s shot missed its mark; Goldie obtained possession of the ball, and tried also in vain; then the guards asserted themselves, and took it away. With lightning rapidity, it passed down the floor to the opponent’s basket. Marjorie felt her knees actually shaking; there seemed to be no doubt that the other team was superior, that they were going to beat
- 74. them by a big score. It was maddening to have to stand still and watch her guards do all the work, but for several minutes the ball neither came over the line nor went into the basket. Sophia and Stella were certainly fighting courageously. At last, however, the ball whizzed back to Dot, and passed on to the other end of the floor, once again giving Goldie and Annie a chance to shoot. But they found it no easy task. Without overguarding a sixteenth of an inch, their opponents seemed able to prevent their making a clear shot; finally Annie made use of her height, and aimed for a one-point shot. The ball fell through the basket; the wild cheering that followed seemed to tell them that now they were started, and nothing should prevent their going on to victory. The rest of her team resumed their positions with an unconscious air of confidence, but Marjorie herself returned to her circle with the same apprehension in her heart. They had scored, to be sure, but the other team was ahead; worst of all, she had not yet outwitted her opponent in the toss-up. As long as she failed at the jump, her own team would be at an enormous disadvantage. She made another valiant attempt, but failed again; her own team, remembering their coach’s instructions, seemed suddenly, one and all, to throw themselves into a defensive game. For seven minutes they held their opponents without a single point being scored. Then, just before the conclusion of the first half, one of the forwards made a one-point shot. The whistle blew, leaving the score at 3–1, in Troop One Sixty-one’s favor. Marjorie’s whole team hurried immediately over to Jack, who was sitting in a corner of the gymnasium. What, they all demanded in confusion, must they do to conquer their opponents? Jack looked from one to the other in silence, waiting for them to calm down before he answered. “Every girl is playing her position splendidly,” he said slowly, “with the exception of the jumping-center.” “I know it!” cried Marjorie with sincere humility.
- 75. “You’re playing wild, Sis,” he continued. “You haven’t landed the jump once—and after the ball is in play the rest of the team can’t depend on you. Poor little Dot is being overworked!” “I don’t mind it!” exclaimed the latter, her eyes shining with excitement. “But that won’t do!” objected the coach. “Every girl has got to play her position, if you want to win.” “What can I do, Jack?” asked Marjorie desperately. “Why, this is what I’m going to try: You know you used to be a pretty good shot as a forward, so I’m going to move you up, and put Annie in the center. She’s quick and tall; I believe that she can get the ball.” “That’s a great idea!” exclaimed his sister, in obvious relief. She believed that her own nervousness before each toss-up was actually rendering her helpless. If this were removed, she might be able to get into the game with her old time speed. The coach took Annie aside and began to give her some further instruction regarding her new position, while Marjorie dashed up to the balcony to see Lily and John. To her amazement she found the latter gone. “Where is he?” she demanded instantly. Lily smiled at her chum’s frank distress. “He had to go on an errand,” she replied; “but he’ll be back. You’re doing splendidly, Marj,” she added. “Do you feel all right?” “Yes—yes, of course,” answered the other girl, who was on too great a tension to know how she actually felt. Then she told Lily of the change Jack was effecting for the second half. “I know that you’re going to win!” Lily assured her gaily. “Lil—has Mr. Richards gone, too?” inquired Marjorie, suddenly growing suspicious lest something had happened. “Yes, I believe he had some sort of work to do.” “Seems funny,” muttered Marjorie. “I can’t understand John’s leaving, since he never mentioned any engagement to me, or errand
- 76. of any sort. Well, I guess I better go practice shooting baskets till the whistle blows.” She went back to the floor, feeling something of her old confidence returning. She was an experienced forward, having played the position almost as often as that of center; moreover, she was sure that her aim was good. The practicing, too, only served to confirm this assurance, for time after time the ball fell through the basket. When the second half was about to begin, she was all eagerness to try her skill. The change which Jack had suggested proved his wisdom immediately; at the very first toss-up, Annie tapped the ball right into her side-center’s hands. Loyal little scout that she was, Dot was only too anxious to give Marjorie a chance to make good, and selected her, rather than Goldie, as the recipient of her pass. Marjorie jumped higher than she had jumped in the center to catch it, and with perfect sureness of aim, tossed it right into the basket. In less than a minute’s time, Sunflower team had tied the score. Marjorie’s joy knew no bounds; during the applause that followed, her eyes sought John’s, but he was still absent; in Lily’s however, she read encouragement and approval. It was Cornflower Troop’s turn to play the defensive game, and with a mighty effort they threw themselves into the task. But the advantage remained with Marjorie’s players, for Annie Marshall continued to land the jump. Both teams were too strong on the defensive to allow their opponents to run up high scores; nevertheless, slowly, but surely, Sunflower steadily gained. Not only did Annie prove a better center than Marjorie, but Marjorie proved a better forward than Annie. It was almost a foregone conclusion that whenever she secured the ball she would make a goal. At last the time was up; the whistle blew, and the game was over. Troop Two Hundred had conquered their opponents by a score of 16–7; the League championship was theirs. Hardly waiting to congratulate her girls, Marjorie dashed off to find John and Lily.
- 77. “It was marvellous!” cried her chum delightedly. “You make a wonderful forward——” “Lil, where’s John?” interrupted Marjorie, in perplexity. “He had to go, dear,” replied Lily. “But Dick will take us home.” “Thanks, but I guess Jack’s willing——” “Jack had to hurry off, too; he just waved to me from the door.” “Jack!” repeated Marjorie. “Why in the world? And Mr. Richards?” “I told you before that he had to go.” Marjorie seized Lily’s shoulder. “Something’s wrong, Lil! I know it! Tell me quick! Is it Mother—or Dad?” “No, Marj—it’s—Queenie. But you mustn’t worry. The boys are going to do whatever can be done.” “What’s the matter with her?” demanded Marjorie, her face pale with fatigue and alarm. “We’re afraid she has eloped—or has run away to meet that man and elope. But luckily John guessed something of the sort, and is going to follow on her trail. I have every hope he’ll catch her.” Marjorie dropped wearily into the seat behind her, too disheartened, too tired for words. The League championship was forgotten; nothing mattered now if Queenie was gone!
- 78. CHAPTER XXI. THE PURSUIT. When John Hadley came to the basket-ball game on Saturday, he brought with him some illuminating facts about Sam MacDonald’s history for Marjorie’s consideration. But the absence of Queenie Brazier from the team decided him in favor of silence—for the time being at least. It was after Marjorie had actually started to play that he concluded that there might be a good reason for Queenie’s failure to put in an appearance—a reason connected with the young man whose record he had just traced, and which he had found to be so precarious. Without giving much attention to the game, he went over the whole situation in his own mind, deciding finally to take Mr. Richards into his confidence. “I have found out about MacDonald—that friend of Queenie’s,” he whispered to the scout-master, “and know that he isn’t any good. That’s an assumed name—his real one is George Hinds—and he has served a term in an Ohio prison.” Mr. Richards, however, was inclined to give the man the benefit of the doubt. “Maybe he’s reformed—you couldn’t blame him for changing his name to get a clean start,” he suggested. “But he hasn’t made a clean start—that’s just the difficulty. They are after him now for a contemptible crime—and they have his picture on record at City Hall. That’s how I identified him.” “They haven’t caught him, then?” “No; he’s sneaked out of the city, of course. Now, what worries me, naturally, is that he may have tried to lure Queenie after him. He does that sort of thing.”
- 79. “Then we’ve got to locate Queenie!” cried Richards, alert for action. “Yes, for even supposing he were honest in his desire to marry her, he’s no sort of man for her to throw herself away on.” “Obviously not. What shall we do first?” “Go to the girl’s home. I’ll give Lily an inkling of the situation, and get Queenie’s address. Marjorie mustn’t hear a word about it until the game is over—then Lily can use her own discretion.” “Right!” agreed the other, in admiration of John’s direct reasoning and well calculated plan. They lost no time in securing the desired information and hurried off in John’s car to the girl’s home. If only they might find her there —and thus end all their fears! But Mrs. Brazier’s reply immediately dashed all their hopes to the ground. “Why no—she ain’t here. She left about half-past seven for the basket-ball game,” the woman told them cheerfully. She identified Mr. Richards by his uniform, for she had often heard her daughter speak of him. “Did you look in on the game?” “Perhaps she is there by now,” answered the scout-master, unwilling to arouse the mother’s suspicions. “Did she carry a suit- case?” “Yes, she always does—a bag for her shoes and bloomers. She must ’ave went there, because I noticed the bag. I picks it up, and I says to her, ‘It’s heavier than usual,’ and she says it had oranges in it —they was goin’ to have eats after the game.” “Yes, yes, of course,” said John, drawing his own conclusions. “Well, I guess she’s there by now. We’ll go back. Thank you, Mrs. Brazier.” No sooner were they in the car than they both blurted out the same solution. “She’s going off to elope with Hinds!” “Which station shall we go to first?” demanded Richards.
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