As an architect or builder, your building needs to comply with the Energy Conservation and Building Code (ECBC) brought out by the Bureau of Energy Efficiency (BEE), Ministry of Power, Government of India. This code is essentially a document that specifies the energy performance requirements for all commercial buildings that are to be constructed in India. Buildings with an electrical connected load of 500 kW or more are covered by the ECBC.
Some of the elements of a building for which the ECBC provides design norms for are:
Window Wall Ratio is the ratio of the building's total window area, measured to the outside of the frame, to the gross exterior wall area
Window wall ratio = Total Glazing / Total gross area
Compliance with the ECBC can be accomplished through three different approaches, depending on the flexibility desired, expertise available, and general process that the designer finds suitable to the project.
The Code provides three options for compliance:
Component Base Approach (Prescriptive): It specifies the minimum performance requirement for each building components like windows, walls, lighting, air-conditioning etc. This approach is quick and easy to use but somewhat restrictive because requirements have to be met exactly as specified for each component depending on climatic zones .
System Based Approach (Trade-Off): It allows the designer to trade enhanced energy efficiency in one component against decreased energy efficiency in another component thereby offering flexibility. This trade-offs typically occur between components of major building system eg: envelope, lighting and or mechanical system. The Solar factor or the Solar Heat gain coefficient of the prescriptive requirements can be traded off with the use of the shading devices/overhangs and/or side fins.
Whole Building Design Analysis Approach (Performance): It compares a proposed design with a reference design and demonstrates the proposed design is more energy efficient than the reference design. This approach allows greater flexibility and is done using sophisticated software and ensures that the energy performance index of the building is as mandated by ECBC.
The following are the compliance requirements with respect to the glazing of buildings for energy-efficiency.
Some of the elements of a building for which the ECBC provides design norms for are:
- Building envelope, including thermal performance requirements for walls, roofs, and windows
- Lighting system, including daylighting, and lamps and luminary performance requirements
- HVAC system, including energy performance of chillers and air distribution systems
Window Wall Ratio is the ratio of the building's total window area, measured to the outside of the frame, to the gross exterior wall area
Window wall ratio = Total Glazing / Total gross area
X = Vision area
Y = Total Gross wall area
Window Wall area = X / Y
Climatic Zones
The code takes in to consideration the climatic conditions. There are 5 distinct climatic zones in India and the ECBC takes in to account these climatic zones for Building Envelop Design.
Y = Total Gross wall area
Window Wall area = X / Y
Climatic Zones
The code takes in to consideration the climatic conditions. There are 5 distinct climatic zones in India and the ECBC takes in to account these climatic zones for Building Envelop Design.
- Hot & Dry (Ahmedabad)
- Warm & Humid (Mumbai, Chennai, Kolkotta)
- Composite (New Delhi)
- Temperate (Bangalore)
- Cold (Shillong)
Compliance with the ECBC can be accomplished through three different approaches, depending on the flexibility desired, expertise available, and general process that the designer finds suitable to the project.
The Code provides three options for compliance:
Component Base Approach (Prescriptive): It specifies the minimum performance requirement for each building components like windows, walls, lighting, air-conditioning etc. This approach is quick and easy to use but somewhat restrictive because requirements have to be met exactly as specified for each component depending on climatic zones .
System Based Approach (Trade-Off): It allows the designer to trade enhanced energy efficiency in one component against decreased energy efficiency in another component thereby offering flexibility. This trade-offs typically occur between components of major building system eg: envelope, lighting and or mechanical system. The Solar factor or the Solar Heat gain coefficient of the prescriptive requirements can be traded off with the use of the shading devices/overhangs and/or side fins.
Whole Building Design Analysis Approach (Performance): It compares a proposed design with a reference design and demonstrates the proposed design is more energy efficient than the reference design. This approach allows greater flexibility and is done using sophisticated software and ensures that the energy performance index of the building is as mandated by ECBC.
The following are the compliance requirements with respect to the glazing of buildings for energy-efficiency.
Compliance Requirement : Glass Light Transmission | |
WWR | Minimum Light Transmission |
< 30% | 27% |
31% to 40% | 20% |
41% to 50% | 16% |
51% to 60% | 13% |
61% to 70% | 11% |
Compliance Requirement : Heat Gain through glazing | ||||
Climate Factor | WWR Ratio | |||
≤ 40% | 41% to 60% | |||
SF or SHGC | U Value | SF or SHGC | U Value | |
Hot & Dry | 0.25 | 3.3 | 0.2 | 3.3 |
Composite | 0.25 | 3.3 | 0.2 | 3.3 |
Warm & Humid | 0.25 | 3.3 | 0.2 | 3.3 |
Moderate | 0.4 | 6.9 | 0.3 | 6.9 |
Cold | 0.51 | 3.3 | 0.51 | 3.3 |
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