ASHRAE Journal - February 2015 - S11

located in a composite climate (Delhi) has been optimized
following a step-by-step approach to treat every element of
the façade, thereby reducing energy demand at the source
itself. The second section quantifies the energy benefits
achieved by installing new technologies available in the
market. Finally, the last section addresses how the façades
in future will transform buildings. The various parameters
of the selected building are given in Table 1.
Table 1: Parameters of selected building.
S. No.
1.
2
3.
4.
5.
6.
7.

Parameter
Usage
Location
No. of floor
Wall
Roof
Glazing
Built-up area

Description
Midrise commercial building
Delhi (composite climate)
9
230 mm thick brick work (U= 1.8 W/m²K)
150 mm concrete (U = 2.3W/m²K)
6 mm thick single clear glass
30,000 sqm

In order to quantify the energy guzzling consequence of a
non-treated façade, the initial estimates revealed that 25%
of the space heat gain was contributed by internal loads and
occupancy demand, 28% heat gain came from treatment of
ventilation air, and the envelope contributed the remaining 47% (Figure 2.) The envelope was further categorized in
façade elements and the roof element. The façade elements
contributed almost as high as 90% gains in the building, of
which, nearly one fourth was contributed by poorly-selected
wall material and three fourth was from ill-treated windows.
Hence, the study quantified the fact that various elements of
the façade make a significant contribution towards energy
gains, and optimizing each of them could help in achieving a
well-designed building. For instance, Figure 3 highlights how
radically rethinking / reassembling/ redesigning buildings
as systems offers new pathways of increased environmental
performance and value creation at lower cost, while providing
more comfort. The integrated façades component design in
Singapore-ETH Centre Future Cities Laboratory reduces the
building volume by 33% while providing the same useful floor
space. This, not only reduces the conditioned volume, but also
façade and glazing areas and their heat gains, structural loads
and consequently all materials and cost associated with these
elements, thus demonstrating that design integration can
make façades function more than an envelope.

Façade Optimization through Passive Strategies
A simulation model was created using e-Quest software to
compute the energy consumption and to study the effect of
various improvements planned in the design. The annual
energy consumption of the untreated building worked out to
9,120 mWh with a cooling load of 2000 TR generating 7,843
Tons of carbon every year.
As a matter of interest, the building was modeled in
four different climatic zones of India and the energy
ACREX INDIA 2015: OFFICIAL SHOW GUIDE

Figure 2: Pie chart highlighting contribution of façades in building envelope.

Figure 3: Singapore-ETH Centre Future Cities Laboratory façade design.

Figure 4: Façade performance in various climate zones.

consumption pattern at different locations was quantified. The study revealed that, whereas the internal heat
gains due to lighting/occupancy/equipment were largely
the same, there was a variation in ventilation and façade
heat gains depending on the location. Thus, with the use
of heat recovery devices (wheels/heat exchangers, etc.) in
the ventilation air stream and by treating the façade to get
an optimized performance, it is possible to ensure that any
building will have nearly similar performance irrespective
of the climatic zone (Figure 4).
As a first step, the following fundamentals of green design
were adopted in terms of optimizing façade performance:
FEBRUARY 2015

ASHRAE Journal - February 2015

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