Energy Efficiency in Building Design and Construction

1.0 Introduction:

A study conducted by Energy Information
Administration, (EIA), U.S. Department of Energy
indicates that there is a visible trend across the globe
wherein the growth rate in total energy consumption
has been greater than the population growth rate.
In the developed countries the energy consumption
growth rate is only marginally higher compared to the
population growth rate. For example, in USA, energy
consumption is projected to grow at 1.3% while the
population growth rate is projected to grow at 0.8%.
In contrast, in developing countries like India population growth rate is expected to
grow at 1.3% while the energy consumption ra te is expected to grow at 4.3%.
This trend would strain the energy sector to a large extent.
The construction industry in the country is growing at a rapid pace and the rate of
growth is 10 % as compared to the world average of 5.2%. Hence energy efficiency
in the building sector assumes tremendous importance.
Commercial buildings are one of the major consumers of energy and are the third
largest consumers of energy, after industry and agriculture. Buildings annually
consume more than 20% of electricity used in India.
The potential for energy savings is 40 – 50% in buildings, if energy efficiency
measures are incorporated at the design stage. For existing buildings, the potential
can be as high as 20-25% which can be achieved by implementing house keeping and
retrofitting measures.
The incremental cost incurred for achieving energy efficiency is 5-8% vis-a-vis
conventional design cost and can have an attractive payback period of 2-4 years.
CII-Sohrabji Godrej Green Business Centre
LEED - Platinum Rated
63% Energy Savings
Confederation of Indian Industry
CII-Sohrabji Godrej Green Business Centre

1.1 Typical Energy Consumption Pattern in Buildings:

Figure 1: Break-up of energy consumption in a building
Typical break-up of energy consumption in a building is as shown in Fig 1.
In a typical building, air conditioning is the highest consumer of energy followed by
lighting and other miscellaneous equipment. Therefore, if the initial design considers
energy efficiency measures in these areas, substantial energy savings can be realised.

2.0 Typical Energy Saving Approach In Buildings:

2.1 Orientation:

This is the f irst step to achieve energy efficiency. The
following measures can be adopted:
v Minimize exposure on the south and west
v Use simulation tools and techniques which can
help in designing the orientation to minimise
heat ingress and enhance energy efficiency.

2.2 Building Envelope:

Figure 2: Typical break-up of heat gain in a building
Wipro Technologies, Gurgaon
LEED – Platinum Rated
40% Energy Savings
Confederation of Indian Industry
CII-Sohrabji Godrej Green Business Centre

Typical heat gain through the building envelope is shown in Fig.2
The following envelope measures can be considered:
v Select high performance glazing with low U-value, low Shading Coefficient and
high VLT (Visual Light Transmittance).
v Insulate the wall. The options for insulation materials can be - Extruded
polystyrene, Expanded polystyrene (thermocol), Glass wool e tc.,
v Brick wall with air cavity can also significantly reduce the heat ingress.
v Hollow blocks, Fly ash bricks and Autoclaved Aerated Concrete (AAC) Blocks
are also good insulators.
v The heat ingress through the roof can be as high as 12-15%. Insulating the
roof can substantially reduce the heat ingress.
v Consider shading devices for window openings.

2.3 Equipment & systems:

v Select chillers with high Coefficient of Performance
(CoP).

v Install Variable Frequency Drives (VFD) for supply &
return air fans and pumps.
v Select high efficiency cooling towers.
v Use high efficiency motors, transformers and pumps.
v Install Heat recovery wheels and economizers
v Consider night purging with ambient air to flush out
the heat trapped within the building during the day
v Adopt Controls & Building Management Systems for effective control
v Engage a Commissioning Authority to ensure that savings are realised once the
building becomes operational

2.4 Lighting:

v Design in such a way that the building gets maximum day lighting.
v Overall lighting power density can be designed as less as 1.0 W/sq.ft.
v Use daylight-cum-dimmer controls
v Install occupancy sensors
v Select energy efficient luminaires like CFL, T-5, LED, etc.,
ITC Green Centre, Gurgaon
LEED-Platinum Rated
45% Energy Savings
Confederation of Indian Industry
CII-Sohrabji Godrej Green Business Centre

3.0 LEED India Rating System & Energy Efficiency:

The LEED (Leadership in Energy and Environmental
Design) green building rating system developed by the
US Green Building Council is now recognised as an
international rating system and followed by more than
24 countries. The LEED rating system has been
indigenized by the Indian Green Building Council to
suit the national context and priorities. Energy efficiency in design has been achieved
by a number of buildings in India by adopting the LEED India green building rating
system.
A LEED rated building consumes 30-50% lower energy as compared to a conventional
building. These buildings are designed to surpass the ASHRAE 90.1.2004 standards or
ECBC (Energy Conservation Building Code).
Energy performance of three ‘LEED Platinum’ ra ted buildings have been monitored for
about 3 years and energy savings achieved are shown in Table -1
Table – 1: Monitoring of energy savings in LEED rated buildings
Building
Built-up
Area
(Sq.ft)
Consumption
of
Conventional
Building
(kWh)
Consumption
of
LEED
Designed
Building
(kWh)
%
Reduction
Annual
Energy
Savings
(Rs in
Lakhs)
Wipro Technologies,
Gurgaon
1,75,000 48,00,000 31,00,000 40% 102
ITC Green Centre,
Gurgaon
1,70,000 35,00,000 20,00,000 45% 90
CII Godrej GBC,
Hyderabad
20,000 3,50,000 1,30,000 63% 9
The IGBC (Indian Green Building Council) has launched two rating programmes LEED
India NC (New Construction) and LEED India CS (Core & Shell). As on date, 195
projects with a built-up area of more than 110 million sq.ft. are registered for
rating. Thus far, 19 buildings have achieved the LEED ra ting in India.
NEG-Micon India (Pvt) Ltd, Chennai
LEED - Gold Rated
Confederation of Indian Industry
CII-Sohrabji Godrej Green Business Centre
5
4.0 Challenges & Opportunities:

Achieving energy efficiency in building poses a number of challenges and at the same
time presents a host of opportunities. A few of them are discussed below:

4.1 Awareness & Training:

Incorporating energy efficiency measures at design
stage requires knowledge of the green building
concepts. There is now a need for skilled and
knowledgeable professionals who have deep
understanding of architecture and energy systems.
IGBC is addressing this through number of training
and awareness programmes all over the country. Thus
far, 3500 professionals have been trained on these
concepts.
Energy simulation programmes are excellent tools to design energy efficient buildings.
The tools typically used are Visual DOE, Energy Plus and Lumen Micro. As of now, the
number of trained professionals on these tools and techniques is scarce. IGBC is
facilitating training of professionals on these tools.

4.2 Availability of Materials, Equipment and Technologies:

The availability and affordability of materials/equipment which contribute to energy
efficiency is another major challenge. Tremendous potential exists for materials &
equipment like heat resistive paints, fly ash blocks, insulation materials, high
efficiency chillers, variable frequency drives, high efficiency cooling towers,
building management systems, lighting controls, BIPV (Building Integrated
Photo Voltaics), etc., New technologies like wind towers, geothermal systems etc.,
are gaining importance. The business opportunity for these products and technologies
in India expected to cross 25 billion USD / annum by 2010. To facilitate the
penetration of these products, IGBC has platforms like Green Building Congress,
Permanent Technology Centre in CII-Godrej GBC, Manufacturers meet, etc., to
showcase energy efficient products.
Grundfos Pumps India Ltd, Chennai
LEED - Gold Rated
Confederation of Indian Industry
CII-Sohrabji Godrej Green Business Centre
6
4.3 Sustained Savings:

A building can have the best of materials,
equipment and systems in place at the design
stage; however, the building can sustain the
savings only if it is monitored on a continuous
basis.
LEED rated buildings use IPMVP (International
Performance Measurement and Verification
Protocol) to monitor and sustain the savings. Proper measurement & verification of
savings will help the building owner to fine-tune the base line and achieve high level
of savings.
Applying rating programmes like LEED EB (LEED for Existing Buildings) can help
buildings to sustain energy efficient practices over the life of the building.

4.4 National Codes and Standards:

Government of India has launched the ‘Energy Conservation Building Code
(ECBC)’ code. This code is voluntary and applicable to buildings or building
complexes that have a connected load of 500 KW or a contract demand of 600 KVA,
whichever is greater. This code addresses the minimum performance standards for
energy efficiency in a building covering building envelope, mechanical systems &
equipment, service hot water heating, interior & exterior lighting and electrical power
& motors. This is an excellent initiative which will enable design of high performance
buildings.

5.0 Conclusion:

With the tremendous growth the country is witnessing, energy efficiency in buildings
assumes paramount importance. The energy saving potential can be as high as 40-
50%, if addressed right at the design stage. The application of codes like ASHARE /
ECBC as a benchmark can help in designing high performance buildings. There exist
tremendous opportunities to introduce new materials, equipment and technologies
which can help enhance energy efficiency of buildings.