Matter for residential Buildings (in events)

Residential Design Guidelines for Composite and Hot-Dry Climates under the Indo-Swiss BEEP

The Indo-Swiss Building Energy Efficiency Project (BEEP) is a bilateral cooperation project between the Ministry of Power (MoP), Government of India and the Federal Department of Foreign Affairs (FDFA) of the Swiss Confederation. The Bureau of Energy Efficiency (BEE) is the implementing agency on behalf of the MoP while the Swiss Agency for Development and Cooperation (SDC) is the agency in charge on behalf of the FDFA.

The overall objective of the project is to reduce energy consumption in new commercial buildings and to disseminate best practices for the construction of low energy residential and public buildings.The project is of 5 years duration and has 4 major components:

Component 1 – Integrated Design Charrettes

Component 2 – Technical assistance in developing building material testing infrastructure

Component 3 – Design guidelines and tools for the design of energy‐efficient residential and public buildings

Component 4 – Production and dissemination of knowledge products

The current set of design guidelines for Energy Efficient Multi-storey Residential buildings have been developed under component 3 of the project and have been issued for 2 climatic zones namely the composite and the Hot-Dry Climates. It gives 15 recommendations on energy-efficiency features in multi-storey residential buildings for integration at the design stage. The guidelines will benefit builders, developers, architects and other building-sector professionals involved in the design and construction of multi-storey residential buildings.

The guidelines are divided into six sections under which these recommendations are featured in.

Building massing and spatial configuration (Recommendations 1–3)

• Recommendation 1: Orient the buildings to minimise solar exposure onexternal vertical surfaces

Longer facades of the building should be oriented north–south direction to minimize solar exposure on external vertical surfaces.

• Recommendation 2: Select the building shape to minimise solar exposureon wall surfaces

• Recommendation 3: Arrange building blocks to benefit from mutual shadingto minimise solar exposure on walls during summer months

Benefits of mutual shading in reducing the solar exposure are possible if thebuildings are closely placed to the east and west of the reference building.

Building envelope (Recommendations 4–6)

• Recommendation 4: Incorporate passive design measures for walls andwindows for reduced energy consumption and improved thermal comfortPackage of Measures I (15%–20% reduction in cooling thermal energy)

Use of light colours on external wall surfaces + fixed window shades withextended overhangs to protect windows from direct solar radiation + betterinsulation of walls + optimised natural ventilation.

Package of Measures II (40%-45% reduction in cooling thermal energy)

Package of Measures I + external movable shutters on windows to cut-off solarradiation falling on windows.

Package of Measures III (50%–60% reduction in cooling thermal energy)

Package of Measures II + improved wall insulation + use of double glazing inwindows + better building air-tightness

• Recommendation 5: Design for adequate daylighting

Day-use spaces like kitchen and living rooms require more attention fordaylight design. Around 10%–15% window-to-wall ratio (WWR) in bedrooms and30% WWR in living room are needed to provide adequate daylighting. Usinglight colour on the internal walls and ceiling helps in improving daylighting.

• Recommendation 6: Insulate the roof and provide reflective surface

Provide overdeck insulation and high reflective surface on roof

Space cooling (Recommendations 7–10)

• Recommendation 7: Design for raised cooling set-pointof around 28 °C

Research indicates that the adaptive comfort setpointtemperature during summer is around 28 °C.

Raising the cooling set-point from 24 °C to 28 °C canbring ~55%–60% reduction in cooling thermal energydemand.

• Recommendation 8: Design the space-cooling systemso as to utilise the full potential of evaporative coolingand fans

A cooling system design that uses full potential ofevaporative cooling can result in 30%–70% electricitysavings annually for space cooling (at 28 °C designset-point) compared to an air-conditioning system.

Provide dedicated space and water supply connectionsfor the installation of evaporative-cooling equipment.

• Recommendation 9: Incorporate energy-efficiencymeasures in the air-conditioning system

Use highest BEE star-rated split or window airconditioners.Incorporation of a central water loop with coolingtower to cool the condensers of split air-conditionersusing water has a 40% energy-saving potential againstair-cooled split air-conditioners.

• Recommendation 10: Design for quick and efficientevacuation of hot air generated in the kitchen

Heat generated in the kitchen, if not evacuatedquickly, can raise the temperature of the adjoining

spaces. Kitchen should be designed for good naturalventilation and properly located mechanical air extraction system.

Appliances (Recommendation 11)

• Recommendation 11: Select higher BEE star-labelledenergy-efficient equipment and appliances

BEE star label is available for distribution transformers,tubular fluorescent lamps, electromagnetic andelectronic ballasts, air-conditioners, ceiling fans,storage-type electric water heaters/geyser, etc.

Common services (Recommendations 12–14)

• Recommendation 12: Energy-efficient lighting design for common areas

Design corridors, staircases, and parking areas to utilise daylighting.

Incorporate energy-efficient artificial lighting design features for both indoor and outdoor lighting of

common areas.

• Recommendation 13: Energy-efficient community water pumping system

Select a pump ensuring that the head and flow parameter for the ‘Duty Point’ matches with that of

the ‘Best Efficiency Point’ of the pump.

Design piping so as to reduce frictional losses.

Use variable frequency drives (VFDs) on pump motors.

• Recommendation 14: Incorporate energy-efficiency design features in the design of lifts

Use light emitting diodes (LEDs) or compact fluorescent lamps (CFLs) for the lighting of the lift car.

Provide auto switch-off for lights and ventilation fans.

Use VFDs in motors.

Consider feasibility of using lifts that have features, such as gearless system, regenerative braking, etc.

Renewable energy integration (Recommendation 15)

• Recommendation 15: Utilise rooftops of multistory residential buildings for the generation ofhot water and/or electricity using solar energy

For energy-efficient multi-storey residential buildings(energy performance index <30 kWh/m2.year) of upto four storeys, it is possible to generate enoughelectricity through rooftop solar photovoltaic systemsto meet the electricity consumption for a year. Thusit is possible to aspire for net zero-energy multistory residential buildings and neighbourhoods.

In most cases, a substantial part of the electricityrequirement for common services can be met throughrooftop solar PV systems.

In most cases, for multi-storey residential buildingsup to 12 storeys, community solar water heatingsystems on the roof can meet around 70% of theannual electricity requirement for heating water.