Design Strategies for Energy-

Efficient Residential Buildings

28th September 2014

Chandigarh

2

Why Energy Efficient Residential

Buildings ?

Over next 20 years

• Number of urban households expected to double. 300-400% increase in constructed area

• Electricity consumption in residential buildings is expected to increase seven-fold – Requirement to add 100,000 -

150,000 MW of new power generation capacity to meet the peak electricity demand due to growth in the use of room air-conditioners

Source: GBPN (2012), BEE (2011), LBNL (2013), Planning Commission

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Energy Efficiency in Residential

Buildings

Energy-Efficient Design

(Code, Rating, Guidelines,…)

User Behaviour

Energy-Efficient Appliances

(Labeling, super efficient appliances,…)

4 Indo-Swiss Building Energy Efficiency Project

Design Guidelines for Energy-

Efficient Residential Buildings

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How the Guidelines were developed ?

Survey of electricity

consumption in ~800

households in NCR &

Time –series data

Detailed monitoring of sample households.

• space temperature and humidity

• Electricity consumption of space

conditioning equipment

Evaluation of potential energy- efficiency

strategies using various energy simulation

software (TRNSYS, DIVA, Autodesk® EcotectTM ,

SAM, RETScreen, …)

Formulation of guidelines

Development and validation of energy

simulation model for typical spaces, e.g.,

bedrooms, living rooms

Feedback over 1 year

Revision & Update

Study of

International

Experience &

Practices

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Thermal comfort and reduction in electricity

consumption for cooling as the main design

focus

30-60% electricity used for space cooling

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Guidelines - Scope

Building Massing

Building Envelope

Space Cooling Systems

Appliances

Common Services

Renewable Energy

• 15 recommendations presented under 6

sections

•The general concepts of the recommendations provided in the guidelines are known to the designers. •Guidelines presents them in a systematic manner, quantifying potential energy savings possible through individual/combination of measures

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Building Massing & Spatial Configuration

Recommendation 1-3

Minimize solar exposure on

external vertical surfaces,

through:

1. Properly orienting the buildings

i.e. larger façade on North and

South direction

2. Selection of building shape

3. Arranging building blocks to

benefit from mutual shading

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Building Envelope

Recommendation 4

4. Adopt passive measures for Walls & Windows

– Package of Measures –I : Use of light colors on wall (absorptivity ≤ 0.4) +

Window shades with extended overhangs + better insulation of walls +

optimised natural ventilation (18-23% reduction in cooling energy)

– Package of Measures –II: Package of Measures-I+ external movable

shutters on windows (40-45% reduction in cooling energy)

– Package of Measures –III: Package of Measures-II with improved wall

insulation + double glazing + better building tightness (55-60 %

reduction in cooling energy)

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Package 1

+ +

Light colors on wall

(absorptivity: 0.4)

Window shades with overhangs

with side extension

Optimized natural ventilation

200 mm AAC Blocks/hollow

clay blocks (0.7-1.0 W/m2.K)

+

(18-23% reduction in cooling thermal energy)

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Package 2

Package 1 Measures +

Sliding shutter Hinged and top rolling

shutters

(40-45% reduction in cooling thermal energy)

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Package 3

+

50 mm thick XPS insulated

cavity wall 0.5 W/m2.K

Double Clear Glazing

Improved Building

Tightness

(0.3 ACH)

+

Package 2 Measures +

(55-60 % reduction in cooling thermal energy)

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Recommendation 5 Design kitchen for adequate day-lighting and good ventilation

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Recommendation 6 Insulate the roof and provide reflective surface

150mm RCC slab

150mm RCC slab + 75mm PUF, with surface

treatment for reflection

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Space Cooling

Recommendation 7-10

7. Raising the temperature of cooling set-point from 24 to 28 oC (~adapative comfort temperature for summer) can bring ~ 55-60% reduction in cooling thermal energy demand

8. Design the space-cooling system so as to utilise the full potential of natural ventilation, fans and evaporative cooling.

9. Incorporate new and innovative ways for improving efficiency of the room air-conditioners

10.Design for quick and efficient evacuation of hot air generated in kitchen – Natural ventilation

– well-located and efficient mechanical extraction system

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Appliances

Recommendation 11

11.Select higher BEE star labeled

equipments and appliances

e.g. Transformers, Tubelights, ceiling fans,

air-conditioners, etc

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Common Services

Recommendation 12-14

12. Energy-efficient lighting design for common areas

a) Design for day-lighting of corridors, staircases, parking areas.

b) Incorporate energy-efficient artificial lighting features for both indoor and outdoor areas

13. Design for energy-efficient pumping system a) Select pump so that the head and flow

parameter for the ‘Duty Point’ matches with that of the ‘Best Efficiency Point’ of the pump.

b) Design piping so as to reduce frictional losses

c) Use variable flow drives (VFDs) on pump motors.

14. Incorporate energy-efficiency design features in the lifts

a) Use LED/CFL for lighting

b) Provide auto switch-off for lights and ventilation fans

c) Use of VFD drives in motors

d) Consider feasibility of lifts having gearless system, regenerative braking, etc.

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Renewable Energy Integration

Recommendation 15

15. Utilise rooftops for the generation of hot water and/or electricity using solar energy

a) For highly energy-efficient residential buildings (overall EPI < 30 kWh/ m2/year) of up to 4 storey, it is possible to generate enough electricity over a year through rooftop solar PV to meet all electricity requirements. In most cases, a substantial part of the electricity requirement for common services can be met.

b) In most cases, for multi-storey residential buildings up to 12 storeys, community solar water heating systems on the roof can meet around 70% of the annual electricity requirement for heating water

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Conclusions

Business As Usual

Passive Measures Energy

Efficiency in Cooling & Appliances Renewable Energy

Generation

EPI

100%

∽75%

∽50%

∽20%

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Team

Core Team

• BEE

– Sanjay Seth, Girja Shankar

• SDC

– Veena Joshi, Anand Shukla

• Effin’Art Sarl

– Dario Aiulfi, Dominique Chuard,

Kira Cusack, Pierre Jaboyedoff

• Greentech Knowledge Solutions

– Prashant Bhanware, Saswati

Chetia, Kanagaraj Ganesan,

Dheeraj Lalchandani, Sameer

Maithel

Assisted by

– Ashok B Lall Architects

• Ashok B Lall, Charu

Ahluwalia, Smita Chaniwala,

Shweta Manchanda

– Tara Niman Kendra

• Ashraya Arora, Akash Bagchi,

Tanu Bhatt, Pankaj Khanna,

Ritu Malhotra, Amol

Mangrulkar

– Virendra Kothari

– Vijay Matange

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21 Indo-Swiss Building Energy Efficiency Project

Thank you!

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