Green building technologies for reducing pollution

Green Building Technology
By
Mr. Ch. Venkatakrishna
Department of Civil Engineering
JNTUH UCESTH, Kukatpally, Hyderabad

The Bureau of Energy Efficiency (BEE) is an agency of the Government of India, established with the
primary objective of promoting energy efficiency and conservation across various sectors in the country.
Here are key aspects of BEE:
1. Formation and Establishment:
•BEE was formed on March 1, 2002, under the provisions of the Energy Conservation Act, 2001.
•It operates under the Ministry of Power, Government of India, and is headquartered in New Delhi.
2. Mandate:
•BEE’s primary mandate is to formulate policies and strategies to promote energy efficiency and
conservation in different sectors, including industries, transportation, and buildings.
•The agency plays a pivotal role in implementing energy efficiency programs and initiatives throughout
the country.
3. Functions and Responsibilities:
•BEE is responsible for developing and updating energy efficiency standards and labeling for various
appliances and equipment.
•It formulates and implements energy conservation building codes to promote energy-efficient practices
in the construction and operation of buildings.
•The agency conducts energy audits and promotes energy management practices in industries to
optimize energy consumption.
•BEE facilitates energy efficiency projects and programs through partnerships with various
stakeholders, including industries, government bodies, and non-governmental organizations.

4. Star Rating and Labeling Program:
•BEE introduced the Star Rating and Labeling program to designate the energy efficiency
levels of appliances and equipment, making it easier for consumers to make informed choices.
•Appliances such as refrigerators, air conditioners, and washing machines are labeled with star
ratings, indicating their energy efficiency.
5. Energy Conservation Building Code (ECBC):
•ECBC, developed and updated by BEE, provides standards for the design, construction, and
operation of energy-efficient buildings.
•It aims to minimize energy consumption in the building sector and promote sustainable
construction practices.
6. Demand-Side Management Programs:
•BEE actively engages in demand-side management programs to encourage consumers,
industries, and businesses to adopt energy-efficient technologies and practices.

The Energy Conservation Building Code (ECBC) is a set of guidelines and standards developed
by the Bureau of Energy Efficiency (BEE), under the Ministry of Power, Government of India.
ECBC focuses on promoting energy efficiency in the design, construction, and operation of
buildings. Here are key aspects of ECBC:
1. Objective:
•The primary objective of ECBC is to establish minimum energy performance standards for
buildings to reduce energy consumption and promote sustainable construction practices.
2. Coverage:
•ECBC applies to commercial buildings or buildings with a connected load of 100 kW or
contract demand of 120 kVA and above. This includes office spaces, malls, hotels, and other non-
residential structures.
3. Standards and Criteria:
•ECBC provides specific standards and criteria for various components of a building,
including building envelope, lighting, HVAC (Heating, Ventilation, and Air Conditioning)
systems, and electrical systems.
•The code emphasizes the use of energy-efficient materials, appliances, and systems to
optimize energy performance.

4. Zoning Classification:
•ECBC classifies India into different climatic zones, and the code is designed to accommodate
the specific energy challenges and requirements of each zone.
•The climatic zones help tailor the energy efficiency recommendations based on factors such
as temperature, humidity, and solar radiation.
5. Compliance and Certification:
•Builders and developers must ensure that their projects comply with the standards set by
ECBC.
•The BEE provides certification to buildings that meet or exceed the energy performance
requirements outlined in the code.
6. Implementation:
•States and Union Territories in India are encouraged to adopt and enforce ECBC as part of
their building bylaws and regulations.
•BEE, along with state agencies, conducts workshops, training programs, and awareness
campaigns to facilitate the implementation of ECBC.
7. Benefits:
•Implementation of ECBC results in reduced energy consumption, operational cost savings,
and a lower environmental impact.
•Energy-efficient buildings contribute to the overall national goal of energy security and
sustainability.

LEED, which stands for Leadership in Energy and Environmental Design, is a green building
certification program developed by the U.S. Green Building Council (USGBC). LEED provides a
framework for designing, constructing, operating, and certifying buildings and neighborhoods with a
focus on sustainability and environmental performance. Here are key aspects of LEED:
1. Objectives:
•LEED aims to promote sustainable and environmentally responsible practices in the construction
and operation of buildings.
•The program seeks to address various aspects of a building’s impact, including energy efficiency,
water conservation, indoor environmental quality, and materials selection.
2. Certification Levels:
•Buildings can achieve different levels of LEED certification based on the number of points they
earn across various sustainability categories. The certification levels are Certified, Silver, Gold, and
Platinum.
3. Categories and Credits:
•LEED certification is achieved by earning credits in specific categories: Sustainable Sites, Water
Efficiency, Energy & Atmosphere, Materials & Resources, Indoor Environmental Quality, and Innovation
in Design.
•Credits are awarded for implementing sustainable strategies and technologies, such as energy-
efficient design, use of recycled materials, and water conservation measures.

4. LEED for Different Building Types:
•LEED has specific rating systems tailored to different types of buildings, including New
Construction, Existing Buildings, Core & Shell, Homes, and Neighborhood Development.
•Each rating system addresses the unique challenges and opportunities associated with the
respective building type.
5. Global Applicability:
•LEED has gained international recognition, and projects around the world pursue LEED
certification.
•The USGBC has adapted LEED to various regional contexts, incorporating local building
practices and environmental considerations.
6. Adaptation Over Time:
•LEED evolves to stay current with advancements in sustainable design and construction
practices. The program is regularly updated to reflect the latest industry standards and address
emerging environmental challenges.

7. Market Transformation:
•LEED has played a significant role in transforming the building industry by raising awareness
of sustainable practices, influencing building codes, and encouraging the adoption of green building
technologies.
8. Community and Education:
•USGBC provides educational resources and opportunities for professionals seeking to become
LEED Accredited Professionals (LEED AP).
•LEED fosters a community of individuals and organizations committed to sustainable and
regenerative practices.
9. Impact on Building Industry:
•LEED-certified buildings demonstrate a commitment to environmental responsibility, often
resulting in operational cost savings, enhanced occupant health and well-being, and increased
market value.
10. Continuous Improvement:
•LEED’s commitment to continuous improvement is reflected in its ongoing efforts to push the
boundaries of sustainable design, construction, and operation.

Lighting in Buildings:
1. Artificial Lighting:
•Artificial lighting is essential for providing illumination during nighttime hours or in areas
with limited natural light.
•Modern buildings often use energy-efficient lighting systems, such as LED or CFL bulbs, to
minimize energy consumption.
2. Lighting Design:
•Thoughtful lighting design considers the function of each space, creating appropriate
ambient, task, and accent lighting.
•Proper fixture selection, placement, and control systems contribute to energy efficiency and
occupant comfort.
3. Energy Efficiency:
•Energy codes and standards, such as those promoted by organizations like the Bureau of
Energy Efficiency (BEE), encourage the use of energy-efficient lighting technologies.
•Occupancy sensors, timers, and dimmers help optimize energy use by adjusting lighting
levels based on activity and natural light availability.

Daylighting in Buildings:
1. Definition:
•Daylighting refers to the use of natural sunlight to illuminate interior spaces within a building
during daylight hours.
2. Benefits:
•Enhances well-being and productivity by providing a connection to the outdoors and
exposure to natural light.
•Reduces reliance on artificial lighting, contributing to energy savings and sustainability.
3. Design Considerations:
•Proper orientation and placement of windows, skylights, and other openings are crucial for
effective daylighting.
•Shading devices, like overhangs or blinds, are employed to control glare and optimize natural
light.

4. Building Performance:
•The Energy Conservation Building Code (ECBC) in India and similar standards worldwide
may include provisions for daylighting to improve energy efficiency.
•Interior design considerations, such as reflective surfaces, can enhance the distribution of
natural light throughout a space.
5. Occupant Comfort:
•Daylit spaces contribute to improved visual comfort, mood, and the overall quality of the
indoor environment.
•Well-designed daylighting reduces the need for artificial lighting during the day, contributing
to energy conservation.
6. Technological Advances:
•Innovative technologies, such as automated shading systems and smart glass, enable dynamic
control of daylighting to adapt to changing conditions.

Lighting Requirements:
1. Energy Efficient Lighting:
•Use of energy-efficient lighting systems, especially LED lighting, is recommended.
•The BEE star rating and labeling program classifies fixtures based on their energy efficiency.
2. Lighting Power Density (LPD):
•ECBC sets specific limits on Lighting Power Density (LPD), measured in watts per square
meter (W/m²), depending on the building type and function.
3. Exterior Lighting:
•Exterior lighting requirements may specify maximum power allowances for outdoor fixtures
and may encourage the use of motion sensors and timers.

Daylighting Requirements:
1. Window-to-Wall Ratio (WWR):
•ECBC provides guidelines for the Window-to-Wall Ratio (WWR), defining the maximum
allowable percentage of window area relative to the total wall area. The specific value depends on
the building type and climatic zone.
2. Visible Transmittance (VT) for Glazing:
•Specifications for glazing include factors like Visible Transmittance (VT) to ensure a balance
between maximizing natural light and controlling solar heat gain.
3. Shading Devices:
•Recommendations for effective shading devices may include specifying the depth and type of
overhangs or other shading solutions.

4. Solar Access:
•Guidelines may address the angle and positioning of buildings to ensure optimal solar access
for natural light.
5. Interior Illuminance Levels:
•Illuminance levels, measured in lux, for various interior spaces may be specified to ensure
adequate light levels for different functions.
6. Occupancy Sensor Controls:
•ECBC and other codes may recommend or require the use of occupancy sensors to control
artificial lighting in response to occupancy patterns.

Status of energy use in buildings

1. Rising Energy Demand in Buildings:
•India’s growing population and urbanization contribute to an increasing demand for energy in
the construction and operation of buildings.
•Residential and commercial buildings collectively account for a significant portion of the
country’s total energy consumption.
2. Energy Inefficiency in Existing Buildings:
•Many existing buildings in India, especially older ones, may lack energy-efficient features.
Inefficient lighting, traditional HVAC systems, and poor insulation contribute to higher energy
consumption.
3. Government Initiatives for Energy Efficiency:
•The Bureau of Energy Efficiency (BEE) in India has been actively working to promote
energy efficiency in various sectors, including buildings.
•The Energy Conservation Building Code (ECBC) sets standards for energy-efficient building
design and construction, focusing on parameters such as lighting, HVAC, and insulation.

4. Renewable Energy Integration:
•India has been making strides in integrating renewable energy sources into buildings.
•Government incentives and policies encourage the installation of solar panels on rooftops,
contributing to both energy savings and the reduction of carbon emissions.
5. Green Building Certification:
•The adoption of green building certification systems, such as LEED and GRIHA, has been
increasing.
•These certifications promote sustainable building practices, covering aspects like energy
efficiency, water conservation, and indoor environmental quality.
6. Challenges in Implementation:
•Despite initiatives and awareness, challenges persist. Affordability of energy-efficient
technologies, particularly for the masses, remains a concern.
•The informal housing sector, which constitutes a substantial portion of India’s urban
population, poses challenges in implementing standardized energy-efficient practices.

Estimation of energy use in a building

The estimation of energy use in buildings involves assessing and predicting the amount of energy
a building is likely to consume for various purposes, including heating, cooling, lighting, and
appliances. This process is essential for understanding energy needs, optimizing efficiency, and
implementing strategies for conservation. Here are key aspects of estimating energy use in
buildings:
1. Energy Modeling:
•Energy modeling involves using computer simulations and mathematical models to predict a
building’s energy performance.
•Building energy simulation software takes into account factors such as climate, building
materials, occupancy patterns, and equipment to estimate energy consumption.
2. Building Characteristics:
•Factors like building size, orientation, insulation, and the type of construction materials
significantly influence energy use.
•Assessing the thermal properties of the building envelope (walls, roof, windows) helps
estimate heat gain or loss.
3. Occupancy Patterns:
•Understanding how a building is used, including occupancy schedules and space utilization,
helps in estimating energy use accurately.
•Different occupancy patterns affect heating, cooling, lighting, and plug load requirements.

4. HVAC Systems:
•Heating, Ventilation, and Air Conditioning (HVAC) systems are major contributors to energy
consumption in buildings.
•Estimation involves evaluating the efficiency of HVAC equipment, the design of the system,
and the climate conditions.
5. Lighting Systems:
•Lighting efficiency, control systems, and natural daylighting considerations impact energy
use for lighting.
•Estimation involves calculating the expected lighting load based on the type of fixtures,
bulbs, and control strategies.
6. Appliances and Equipment:
•Estimating energy use from appliances and electronic equipment involves considering the
type, usage patterns, and energy efficiency of these devices.
•The proliferation of smart appliances and energy-efficient equipment has an impact on
overall consumption.

7. Local Climate:
•The climate of the region where the building is located plays a crucial role in estimating
energy needs.
•The degree days method, considering heating and cooling degree days, helps evaluate the
energy required for temperature control.
8. Energy Codes and Standards:
•Compliance with energy codes and standards, such as the Energy Conservation Building
Code (ECBC), aids in estimating energy use by providing specific benchmarks for energy
performance.
9. Occupant Behavior:
•Estimation should account for occupant behavior, such as preferences for temperature
settings, usage patterns, and response to energy-efficient measures.
10. Continuous Monitoring:
•Actual energy consumption may deviate from estimates due to changes in occupancy,
equipment, or system performance.
•Continuous monitoring and adjustments based on real-world data help improve the accuracy
of energy use predictions.

Heat gain and thermal performance of building
envelope

Heat Gain:
Heat gain in a building refers to the increase in internal temperatures due to external factors such
as solar radiation, conduction, and convection. It is a critical consideration in building design and
energy efficiency. Key contributors to heat gain include:
1. Solar Radiation: The sun’s rays can directly enter a building through windows and walls,
leading to an increase in temperature. Effective shading systems and reflective materials help
minimize solar heat gain.
2. Conduction: Heat can transfer through building materials, especially if they have poor
insulating properties. Proper insulation and the use of thermal barriers help reduce heat transfer
through conduction.
3. Convection: Air movement, both outside and inside the building, can contribute to heat gain.
Well-designed ventilation systems and airtight construction can help control convection-related
heat gain.

Thermal Performance of Building Envelope:
The building envelope, comprising walls, roof, windows, doors, and floors, plays a crucial role in
managing heat gain and loss. Thermal performance refers to how well the building envelope
insulates against external temperature fluctuations. Key factors include:
1. Insulation: High-quality insulation materials are essential for reducing heat transfer through
walls, roofs, and floors. This helps maintain a comfortable interior temperature and reduces the
need for excessive heating or cooling.
2. Windows and Glazing: Energy-efficient windows with low emissivity coatings and insulated
glazing help control solar heat gain while allowing natural light. Properly sealed windows prevent
air leaks, enhancing thermal performance.
3. Ventilation: Well-designed ventilation systems contribute to the thermal performance by
maintaining indoor air quality and controlling temperature. Controlled ventilation helps prevent
overheating and minimizes the need for additional cooling.

4. Thermal Mass: Materials with high thermal mass, such as concrete or masonry, can absorb and
store heat, moderating temperature fluctuations. This can be strategically used to enhance the
thermal performance of a building.
5. Airtightness: Airtight construction prevents uncontrolled air leakage, reducing heat loss or gain.
Proper sealing of gaps and joints in the building envelope is crucial for improving thermal
performance.
6. Shading: External shading devices, such as overhangs, shades, or louvers, can effectively block
or diffuse solar radiation, reducing the impact of direct sunlight and minimizing heat gain.

Steady and non-steady heat transfer through the glazed
window

Steady-state and non-steady-state (transient) heat transfer are concepts used to describe the thermal
behavior of glazed windows over time.
Steady-State Heat Transfer:
Definition:
• Steady-state heat transfer refers to a condition where the temperature within the system or material
remains constant over time. In other words, there is no change in temperature with respect to time.
Characteristics:
• In a steady state, the heat flow into and out of the glazed window reaches equilibrium, and the
temperatures across the window components remain constant.
• For a window, this means that the temperature on the interior and exterior surfaces, as well as within
the glazing material, does not change.
Application:
• Steady-state conditions are often assumed for simplified analyses, especially when considering long-
term energy performance of buildings.

Non-Steady-State (Transient) Heat Transfer:
Definition:
• Non-steady-state (transient) heat transfer refers to a condition where temperatures within the
system or material change with respect to time. It accounts for dynamic variations in temperature
over time.
Characteristics:
• In non-steady-state conditions, the temperature distribution within the glazed window changes
over time due to factors such as variations in external conditions, solar radiation, or changes in
indoor heating/cooling loads.
• Transient heat transfer is crucial for understanding how quickly a glazed window responds to
external changes in temperature or other environmental conditions.
Application:
• When analyzing short-term temperature fluctuations, such as daily or seasonal variations, or
when considering the response of a window to sudden changes in environmental conditions, non-
steady-state heat transfer analysis becomes important.

Considerations for Glazed Windows:
1. Steady-State Analysis:
•Steady-state analysis is suitable for assessing long-term energy efficiency and thermal
performance of windows under relatively constant environmental conditions.
2. Non-Steady-State Analysis:
•Non-steady-state analysis is essential for understanding how quickly a window responds to
external changes, such as temperature variations throughout the day or sudden changes in weather
conditions.
3. Dynamic Factors:
•Glazed windows experience both steady-state and transient conditions. External factors like
solar radiation and ambient temperature variations lead to dynamic heat transfer patterns.
4. Energy Performance:
•Understanding both steady and non-steady-state heat transfer is crucial for evaluating the
overall energy performance of glazed windows in different climates and under varying operating
conditions.

Steady and non-steady heat transfer through the
wall

Steady-State Heat Transfer through Walls:
Definition:
•Steady-state heat transfer through walls occurs when the temperature within the wall remains
constant over time. In other words, there is no change in temperature with respect to time.
Characteristics:
•In a steady state, the rate of heat flow into and out of the wall reaches equilibrium, and the
temperatures at different points within the wall remain constant.
•Steady-state conditions are often assumed for simplified analyses when considering long-
term thermal performance.
Application:
•Steady-state analysis is suitable for assessing the long-term thermal behavior of walls under
relatively constant environmental conditions.

Non-Steady-State (Transient) Heat Transfer through Walls:
Definition:
•Non-steady-state (transient) heat transfer through walls occurs when temperatures within the
wall change with respect to time. It accounts for dynamic variations in temperature over time.
Characteristics:
•In non-steady-state conditions, the temperature distribution within the wall changes over time
due to factors such as daily or seasonal variations in external conditions, changes in solar
radiation, or sudden changes in indoor heating/cooling loads.
Application:
•Non-steady-state analysis is essential for understanding how quickly a wall responds to
external changes, especially in scenarios with dynamic temperature fluctuations.

Considerations for Walls:
1. Steady-State Analysis:
•Steady-state conditions are assumed for assessing the long-term thermal behavior of walls
under constant external conditions.
•This analysis helps in understanding the equilibrium temperature distribution within the wall.
2. Non-Steady-State Analysis:
•Non-steady-state analysis is crucial for understanding how quickly a wall responds to
external changes, such as temperature variations throughout the day or sudden changes in weather
conditions.
•Transient heat transfer analysis is essential when evaluating the performance of walls in
dynamic and variable environments.
3. Material Properties:
•The thermal properties of wall materials, including conductivity and specific heat, play a
significant role in both steady-state and non-steady-state heat transfer.

Considerations for Walls:
4. Insulation:
•Insulation materials and their thickness influence the overall thermal resistance of the wall
and impact both steady-state and non-steady-state performance.
5. Building Envelope Dynamics:
•Walls are integral components of the building envelope, and their thermal performance is
influenced by factors such as solar exposure, outdoor temperature variations, and indoor
heating/cooling loads.
6. Energy Codes:
•Compliance with energy codes often involves assessing the overall thermal performance of
building elements, including walls, under both steady-state and transient conditions.

Standards for thermal performance of building
envelope

Several standards and codes guide the thermal performance of building envelopes globally. These
standards provide guidelines for designing and constructing energy-efficient building envelopes.
Here are some prominent ones:
1. ASHRAE Standards:
•ASHRAE 90.1 - Energy Standard for Buildings Except Low-Rise Residential Buildings:
Published by the American Society of Heating, Refrigerating and Air-Conditioning Engineers
(ASHRAE), this standard sets minimum requirements for the energy efficiency of commercial and
high-rise residential buildings. It includes specifications for the thermal performance of building
envelopes.
2. Energy Conservation Building Code (ECBC):
•ECBC by BEE (Bureau of Energy Efficiency), India: This code sets standards for the energy
performance of commercial buildings and is specifically focused on the Indian context. It includes
guidelines for the thermal performance of building envelopes to improve energy efficiency.

3. ISO Standards:
•ISO 6946 - Building components and building elements - Thermal resistance and thermal
transmittance - Calculation method: This ISO standard provides a methodology for calculating the
thermal transmittance (U-value) of building components and elements, including the envelope.
•ISO 13786 - Thermal performance of building components - Dynamic thermal characteristics
- Calculation methods: This standard outlines methods for calculating the dynamic thermal
characteristics of building components, aiding in understanding the thermal behavior over time.
4. LEED (Leadership in Energy and Environmental Design):
•Developed by the U.S. Green Building Council (USGBC), LEED is a green building
certification program. It includes criteria for thermal performance as part of its holistic approach
to sustainable building design.

5. National Building Code (NBC):
•National Building Code of Canada (NBC): The NBC includes provisions for energy
efficiency and thermal performance of building envelopes in Canada. Specific requirements may
vary by province.
6. EN Standards (European Standards):
•EN ISO 6946 - Building components and building elements - Thermal resistance and thermal
transmittance - Calculation method: Similar to ISO 6946, this European standard provides a
calculation method for determining the thermal transmittance of building components.
•EN 12831 - Heating systems in buildings - Method for calculation of the design heat load:
This standard includes calculations related to the thermal performance of building envelopes in the
context of heating systems.

Evolution of the overall thermal transfer

The evaluation of the overall thermal transfer, often referred to as the thermal performance or
thermal transmittance of a building component, is crucial for understanding how effectively the
component resists or conducts heat. One commonly used measure for this evaluation is the U-
value. Let’s delve into the concept:
U-Value:
Definition:
• The U-value, or thermal transmittance, represents the rate at which heat flows through a
building element or assembly. It is expressed in units of watts per square meter per degree Celsius
(W/m²·°C).

Calculation:
• A lower U-value indicates better insulation and reduced heat transfer. It is calculated based on
the reciprocal of the sum of the thermal resistances (R-values) of individual layers within a
building component.
Factors Influencing U-Value:
1. Material Properties: Different materials have varying thermal conductivities, influencing the U-
value.
2. Thickness of Materials: Greater thickness generally leads to increased resistance to heat flow
and a lower U-value.
3. Number of Layers: Multi-layered assemblies may have a lower U-value due to additional
resistance.

Overall Thermal Performance Evaluation:
1. Building Envelope Components:
• Evaluate U-values for various building envelope components, including walls, roofs,
windows, and doors.
• Assess the thermal performance of insulation materials, glazing, and framing systems.
2. Dynamic Factors:
• Consider the dynamic aspects of heat transfer, especially in non-steady-state conditions.
• Analyze how the building component responds to temperature fluctuations over time.
3. Energy Codes and Standards:
•Refer to local energy codes and standards that set specific U-value requirements for
different building components.
•Compliance with these standards ensures that the building meets minimum thermal
performance criteria.

Overall Thermal Performance Evaluation:
4. Computer Simulation and Modeling:
•Use computer simulations and modeling tools to predict and analyze the overall thermal
performance of building components.
•Assess how variations in design or materials impact energy consumption.
5. Localized Evaluation:
•Evaluate U-values in specific regions of the building envelope, taking into account climate,
solar exposure, and local environmental conditions.
6. Integration with HVAC Systems:
•Integrate the evaluation of U-values with the design and sizing of HVAC (Heating,
Ventilation, and Air Conditioning) systems to optimize overall energy efficiency.
7. Life Cycle Assessment:
•Consider the life cycle of building components when evaluating thermal performance. This
includes factors such as material extraction, manufacturing, installation, and disposal.

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