Energy Modelling comparison project
- 1. Certificate in Environmental & Energy Engineering Sustainable Energy Systems Modelling Cork Institute of Technology, Bishopstown, Cork, Ireland INTR8018-2011-May DESIGN STUDY ON THE IMPROVEMENT OF ENERGY EFFICIENCY AT “CLOONBEG”, CASTLEFEKE, CLONAKILTY, CO CORK. MAY 2011 Group Members; Paul Butler RY5212240 John McCarthy R00078838 Colm O Mathuna RY2030161
- 2. Abstract The study undertaken concerned the energy efficient use of the dwelling house “Cloonbeg”, Castlefreke, Clonakilty, Co. Cork. The premises was constructed 1990 circa in accordance with the building regulation governing construction techniques of its era. The premises is a 2 story dwelling house with a two storey extension constructed 2000 circa. The premises is located on a sheltered site from wind and is situated approximately 50m east of a stream with the front of the premises facing in a southerly direction. It was proposed to access the energy efficiency of the dwelling house taking its current energy efficiency as its base case. The proposed case undertaken was the assessment of the enhanced case energy efficiency of the dwelling house using three separate software modelling packages. The three modelling packages utilised include: 1. RETscreen 2. Dwelling Energy Assessment Procedure (DEAP) 3. Simplified Building Energy Modelling (SBEM) The proposed case consisted of upgrading the heat loss elements and envelopes of the dwelling home. This included increasing the insulation in the attic space and providing external insulation to all heat loss external walls. It also included providing energy efficient lighting and upgrading the boiler and heating controls while providing solar panels to contribute towards hot water demands. Using these software modelling packages it was possible to establish a close correlation to base case and proposed case energy requirements of the dwelling home between the software modelling packages. Both the DEAP and SBEM software modelling packages were developed by the Irish and English governments respectively in order to access and develop awareness of the energy efficiency of dwelling homes. This was done as a means of gathering knowledge in order to implement strategies to achieve set CO2 emission regulations. As these programs were developed for similar reasons, similarities can be seen between both. RETscreen also assesses the technical and environmental aspects as well as being a powerful tool for providing financial analysis. Introduction Energy is a valuable resource which is required in our everyday lives at home, for transport and in work. Energy is becoming more expensive to purchase and is producing harmful by-products such as green house gases which is damaging our environment. The main source of fuel for energy production is in the form of fossil fuels. This is an exhaustible fuel which will eventually be depleted. As a result of this the efficient use of energy is a growing concern. The purpose of this project was to examine the energy efficiency of a dwelling home in its existing state as its base case and to analysis the feasibility of implementing energy efficient measures in its upgrade. The energy efficiency upgrading measures included upgrading the heat loss elements and envelopes of the dwelling home to reduce heat loss from poorly insulated elements. This included: Increasing the insulation in the attic space Applying external insulation to all heat loss external wall elements Upgrading tungsten lamps to energy efficient lighting (CFL’s) Upgrading poor efficiency boiler to high efficiency boiler and providing heating controls for full zone control of heating system Providing solar panels to contribute towards hot water demands. Three independent software modelling packages were utilised to examine the technical and environmental aspects of the building “Cloonbeg”, Castlefreke, Clonakilty, Co. Cork. These packages included: 1. RETscreen 2. Dwelling Energy Assessment Procedure (DEAP) 3. Simplified Building Energy Modelling (SBEM)
- 3. Nomenclature kW Kilowatt = 1000 Watts MW Megawatt = 1,000,000 Watts kWh Kilowatt Hour = kW x Hours HHV Higher Heating Value Tonne 1000 Kilograms CO2 Carbon Dioxide Description Premises The premises is a 2 storey dwelling house constructed 1990 circa with a 2 storey extension constructed 2000 circa. Photo 1: “Cloonbeg”, Castlefreke, Clonakilty, Co. Cork. The premises is located in a sheltered site offering little wind potential but is situated approximately 50m east of a stream. The premises is facing in a southerly direction. Photo 2: Ground floor plan of existing dwelling house Photo 3: First floor plan of existing dwelling house Software Packages
- 4. RETscreen was developed by the Canadian Government and is currently operating on its fourth version. It was developed in 1998 and is a Microsoft Excel based software package used to determine the feasibility of clean energy projects and has the means to assess a wide range of energy efficiency technologies. The package includes an in-depth library capable of assisting its interface user in all energy assessment techniques. It is a powerful tool that also has the capability of providing its user with the ability to generate financial and feasibility assessments for its projects. Dwelling Energy Assessment Procedure (DEAP) was developed by the Irish Government to implement the assessment of the energy performance of buildings. DEAP software modelling package is used solely for the assessment of dwelling homes. It is a package that offers both the technical and environmental assessment of the dwelling home based on standard occupancy assumptions and a range of technical judgements based upon the views of various expert organisations regarding the energy efficiency impact of various building components and attributes. In practice the energy efficiency of a building depends on how the occupants operate the building. Simplified Building Energy Modelling (SBEM) was developed by the British Government to implement the assessment of the energy performance of buildings. SBEM software modelling package is capable of assessing the technical and environmental aspects of both domestic and non domestic buildings. Energy Efficiency Measures There are a number of energy efficient measures available that can be used in the upgrading of an existing home. Some of these measures include upgrading heat loss elements, upgrading heating systems including heating controls, improving air tightness within buildings, improving poor efficiency electrical consuming devices with high efficiency devices and by using renewable technologies such as solar panels, hydro turbines, wind turbines, heat pumps etc. The measures implemented in the efficiency upgrade of “Cloonbeg” consisted of: External wall insulation to improve U- Value of wall envelope from 0.55W/m 2 K to 0.19W/m 2 K Additional roof insulation to improve U- Value of roof envelope from 0.418W/m 2 K to 0.134W/m 2 K Upgrading of low efficiency boiler of ɳ=0.808 to a high efficiency boiler of ɳ=0.932 Upgrading of heating control system from programmer time clock to full zone control to allow time and temperature control of the heating system and hot water system The provision of evacuated tube solar panels to contribute to the hot water demands Grants are made available for the measures implemented in this project under the home energy saving scheme as provided by SEAI (Sustainable Energy Authority of Ireland). Measure Category Grant Roof Roof Insulation €250 Wall Cavity wall insulation €400 Internal wall insulation €2,500 External wall insulation €4,000 Heating Controls High Efficiency GAS or Oil fired Boiler with Heating Controls Upgrade €700 Heating Controls Upgrade €500 BER Assessment BER After Upgrade Works (Only one BER grant per home) €100 Table 1 (SEAI Home Energy Saving scheme Application Guide Version 2.0) SEAI also offer a grant scheme to existing homeowners under the Greener Homes Scheme Phase III. Under this scheme they offer grants of €250/m 2 (to max. of 6m 2 ) for Solar – Flat Plate and €300/m 2 (to max. of 6m 2 ) for Solar – Evacuated Tube. Survey Data Please see Table 2 below showing data collected from on-site survey.
- 5. Room Area (sq.m) Opening opening dimensions (sq.m) Glazing Details Frame Gap direction Draught stripping y/n Chimney or Flueless Open Flues Fans / vents Rads with or w/o TRVs? Number of Lights Number of Low Energy Lights GROUNDFLOOR z0/0 1 Dining Room 16.76 Window 2.4 Double Glazed PVC 12 South y - - 0/1 1/o 2 0 Dining Room - Window 0.64 Double Glazed PVC 12 East y - - " " " " Dining Room - Window 2.06 Double Glazed PVC 12 West y - - " " " " z0/0 2 Kitchen 19.77 Window 1.28 Double Glazed PVC 12 East y - - 1/1 1/o 2 0 z0/0 3 Utility 7.58 Window 1.09 Double Glazed PVC 12 East y - - 0/1 1/o 1 0 Utility - Door 2.01 Double Glazed PVC 12 North y - - " " " " Utility - Glazing 0.56 - - - - - - - - - - - z0/0 4 WC 2.73 - - - - - - - - - 1/0 1/0 1 0 z0/0 5 Living Room 18.87 Window 2.55 Double Glazed PVC 12 South y 1 - 1/1 1/o 2 0 Living Room - Window 2.4 Double Glazed PVC 12 West y " - " " " " Living Room - Window 0.64 Double Glazed PVC 12 North y " - " " " " z0/0 6 Entrance Hall 8.19 Door 2.7 Double Glazed PVC 12 South y - - - 1/o 1 0 Entrance Hall - Glazing 1.07 - - - - - - - - - - - z0/0 7 Garage 25.59 - - - - - - - - - - - 2 0 FIRSTFLOOR z1/0 1 Bedroom 1 17.32 Window 1.44 Double Glazed PVC 12 West y - - 0/1 1/o 3 0 Bedroom 1 - Window 1.67 Double Glazed PVC 12 South y - - " 1/o " " z1/0 2 Ensuite 2.6 - - - - - - - - - 1/0 1/o 1 0 z1/0 3 Landing 11.74 - - - - - - - - - - - 1 0 z1/0 4 Bedroom 2 12.29 Window 1.44 Double Glazed PVC 12 East y - - 0/1 1/o 2 0 z1/0 5 Ensuite 5.71 Window 0.72 Double Glazed PVC 12 North y - - 1/1 1/o 1 0 z1/0 6 Bathroom 4.79 Window 0.72 Double Glazed PVC 12 North y - - 1/1 1/o 1 0 z1/0 7 Hall 4.01 - - - - - - - - - - 1/o 1 0 z1/0 8 Bedroom 3 14.87 Window 1.44 Double Glazed PVC 12 South y - - 0/1 1/o 2 0 z1/0 9 Bedroom 4 13.34 Window 1.09 Double Glazed PVC 12 North y - - 0/1 1/o 3 0 Bedroom 4 - Window 1.09 Double Glazed PVC 12 West y - - " " " " z1/1 0 Ensuite 2.28 - - - - - - - - - 1/0 1/o 1 0 z1/1 1 Hall 7.64 Window 1.09 Double Glazed PVC 12 North y - - - 1/o 1 0 Table 2: On-site data survey sheet
- 6. Findings From inspection of “Cloonbeg” , the Building Energy Rating (BER) using the DEAP software (Irish Standard) at the time of inspection was that of a D2 (i.e. 262.72 kWh/m 2 /yr) At the time of inspection it was noted poor building standards had been utilised during its construction for energy efficiency which would be reflective of the time at which it was built. It was noted that the installed boiler had been upgraded from its original boiler but was still of poor efficiency. The use of condensing boilers is common practice in current building standards and would improve the overall energy efficiency of the dwelling home. It was noted that a programmer/time clock was present with no room thermostats present to control the heating system at the time of inspection. Installing a new time and temperature zone control system would allow for much improved control of the heating system providing improved living conditions and improving the overall energy efficiency of the dwelling home. The water cylinder had lagging jacket insulation and no thermostat at the time of inspection. A new factory insulated water cylinder with a thermostat adequately sized to provide sufficient hot water for the estimated number of occupants of the dwelling house would be more efficient and improve the overall energy efficiency. A water cylinder incorporating a twin coil system is required with the provision of solar panels. It was noted that standard lighting is used throughout the dwelling. Replacing this lighting with low energy efficient lighting will save energy use throughout the year and improve the overall energy efficiency of the dwelling home. It was noted that external walls were of cavity block construction been constructed in the early 1990’s with limited insulation. It was also noted that limited insulation was been utilised in the roof space between and over the ceiling joists. Insulation levels can be improved throughout. This will be shown to be feasible in the ceiling area and external walls. Chimneys are an area which lose large quantities of energy. The heat rises up and passes out through the open chimney. If these openings are reduced to an open flue this will reduce the overall heat loss. Fireplaces are also very inefficient with an efficiency rating of 30%. Improving on this by using other means of secondary heating systems which are more efficient such as 65% efficient stove room heater will improve the overall energy rating of the dwelling home. These heating systems will also allow the chimney used for open fires to be reduced to a flue for other secondary heating systems that are more efficient thus improving your overall energy efficiency. Primary Energy Demand = 262.72kWh/m 2 /yr Improvement Primary Energy Demand (kWh/m 2 /yr) CO2 Emissions (kgCO2/m 2 /yr) Upgrading external wall insulation to provide a U- Value of 0.19W/m 2 K 226.02 52.72 Upgrading roof insulation to provide a U- Value of 0.134 W/m 2 K 211.99 49.37 Upgrading of boiler to a high efficiency boiler of ɳ=0.932 191.81 45.11 Upgrading of heating control system to full zone control system 157.08 36.90 Provision of evacuated tube solar panels to contribute to the hot water demands 144.46 34.36 Table 3: Improvements indicated on reducing step basis of proposals implemented using DEAP Software
- 7. Results The energy efficiency was calculated for “Cloonbeg” dwelling home using 3 different software modelling packages as mentioned above. Please see screenshots of the results obtained from each package for the base case and proposed case scenarios below. Screenshot 1: Base Case Results (DEAP Software) Screenshot 2: Proposed Case Results (DEAP Software) From the DEAP software results it can be seen that Primary Energy Demand reduced from 262.72kWh/m 2 /yr to 144.46kWh/m 2 /yr subsequent to the implementation of the proposed measures mentioned above. These implementations offer a saving of 118.26kWh/m 2 /yr on the Primary Energy Demand with a total saving of 27.11kgCO2/m 2 /yr on the CO2 emissions. This offers a total financial savings of €1561.30 per year based on a rate of €0.14/kWh of electricity and €0.07/kWh of LPG fuel. With a budget cost estimate of €21,850 – incentives which amount to €5,922 the total expenditure comes to €15,928. This provides a pay back period of 10.2 yrs. Screenshot 3: Base Case Results (SBEM Software) Screenshot 4: Proposed Case Results (SBEM Software) From the SBEM software results it can be seen that Primary Energy Demand reduced from 288.88kWh/m 2 /yr to 145.65kWh/m 2 /yr subsequent to the implementation of the proposed measures mentioned above. These implementations offer a saving of 143.23kWh/m 2 /yr on the Primary Energy Demand with a total saving of 33.49kgCO2/m 2 /yr on the CO2 emissions. This offers a total financial savings of €1,172.19 per year based on a rate of €0.14/kWh of electricity and €0.07/kWh of LPG fuel. With a budget cost estimate of €21,850 – incentives which amount to €5,922 the total expenditure comes to €15,928. This provides a pay back period of 13.6 yrs.
- 8. Screenshot 5: CO2 Emissions Analysis (RETscreen Software) Screenshot 6: Financial Analysis (RETscreen Software) From the RETscreen software results above it can be seen that there is a savings in CO2 emissions of 2700kgCO2/yr. The base case CO2 emissions were 7.2tCO2/yr with the proposed case resulting in 4.5tCO2/yr. Based on a rate of €0.14/kWh of electricity and €0.07/kWh of LPG fuel RETscreen gives a financial savings of €1,208 per year. This offers a return period of 10 years for the investment. Conclusions/Recommendations From the above analysis it can be seen that RETscreen offers the shortest payback period of 10 years for the investment. This is only slightly less than that of the DEAP software of 10.2 years. SBEM had the longest payback period 13.6 years. SBEM results show large savings in upgrading lighting in comparison to the RETscreen software and the DEAP software and appears unrealistic when compared with hand calculations for lighting also. SBEM results also show very little savings achieved in space heating upon implementing the energy efficient measures. This also doesn’t correlate with RETscreen and with DEAP software as well as expected results. The cost of heating the dwelling home is more significant than the cost of lighting within the home therefore the results generated by SBEM result in a longer payback period than generated by the other two software packages. All three software packages show substantial CO2 savings on the implementation of the energy efficient measures which results in significant savings on green house gases. From the above calculations this project lifetime would be considered a long term investment with a significant payback period. Without government incentives this project would not be financially viable as payback periods of greater than 18 years. The energy efficient measures utilised in the project have a limited lifetime and could be obsolete by the time the investment is returned. The implementation of the above mentioned energy efficient measures did not upgrade the dwelling house satisfactorily to conform to current building regulation Technical Guidance Document Part L. To conform with these regulations additional measures would need to be implemented in the form of upgrading the heat loss element of the floor and providing a source of renewable energy to provide 10kWh/m 2 /yr of the overall floor area of the dwelling home, 4kWh/m2/yr of electrical energy, or a combination of these which would have equivalent effect. Such renewable energy sources could include a wood fired stove/boiler, wind turbine or hydro turbine to name but a few. Some of these measures are not suited to retrofitting and would not be feasible. Acknowledgments The authors wish to thank Mr. Gordon Petrie, Cork Institute of Technology, Chemical Engineering Department for his assistance, advice and direction throughout the year. References Sustainable Energy Authority of Ireland Technical Guidance Document Part L SBEM User Guide 3/12/10 Non-domestic Energy Assessment Procedure (NEAP) Modelling Guide & SBEM Technical Manual version 3.5.a Dwelling Energy Assessment (DEAP) Manual RETscreen Help Desk