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From the name of a colour, green has come to signify a whole new world of environment-friendly products and innovations in design and architecture, says Maria Louis.

If we strip it of the hype and hoopla that surrounds it especially in the month of June, when we celebrate World Environment Day with a vengeance, we will realize that what is considered green today has actually always been an intrinsic part of Indian civilization. Consider the jali windows and courtyards that help cool our interior spaces naturally, thus helping us to save our invaluable natural resources. Like other Indian concepts that have caught on in the West, to be later aped by India, green architecture too is seeing a revival in modern times.

Apart from mud and bamboo for construction, and solar and wind to power large-scale projects, a new-age material used in addition to age-old bricks is aerated autoclaved concrete (AAC) – a material that provides structure, insulation and fire resistance, all in one. Thanks to widespread awareness about the need to save energy, new technology like heat-resistant fly-ash bricks, heat-reflective or low-E glass, double-insulated glass, environment-friendly air-conditioners and HVAC systems are growing increasingly popular. The environment-conscious consumer wants contemporary space design, but demands green design solutions for homes and offices.

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Another bit of good news for all those concerned about the legacy we leave behind for the next generation, is that green is the loudest-voiced concern of the Corporate Social Responsibility (CSR) movement in India, and companies now want to be seen on the Green page even if it means spending that extra piece of green paper.  In the light of this, we draw attention to some path-breaking innovations that exemplify different aspects of green architecture.

Case Study 1
Three tiers for cooling

A column-free space is a dream that does not come true very frequently. When studying the site for the new corporate and administrative offices for Fem Pharma in Nasik, to be located over existing office space in a newly-covered area built using steel trusses and profiled steel roofing, interior designers Conrad Gonsalves & Associates realized that along with the dream column-free space came the challenge of addressing the extensive height and volume within which one had to suspend whatever mechanical services were required.
Since a sizable portion of the space had to be cordoned off into enclosed spaces for a large conference room, canteen and executive cabins, the idea of retaining the full height had to be abandoned and a false ceiling was introduced.  Thanks to a user who was open to technology and committed to using energy-conserving systems, experts in natural cooling systems, Surendra Shah of Panasia, were brought in to design a low-energy system for air-conditioning with inspiration drawn from our heritage buildings that remain cool without using any energy.
The idea was to keep the building from heating up by the sun. Two techniques were used: (1) Barriers and (2) Drain. Then an appropriate energy-efficient air-conditioning system was designed that had two sub systems: (1) For sensible load and (2) For latent and fresh air load.

Tier 1
Barriers:
1. Isolation of the light roof. The light roof was attached with insulating gaskets and treated with a shiny material on the underside to act as a radiant barrier. Then, a false ceiling was planned that would isolate the huge volume of air contained in the trussed section of the space. Roof extractors using only wind power were installed to remove the heated air in the space above the false ceiling.
2. Heat-reflective paint was used on the external walls of the G+1 standalone structure.

Drain:
1. Solar heat absorbed by the RCC portion of the roof and the façade was drained out by a welded grid of iron pipes containing water under vacuum connected to a heat exchanger that used cooling tower water. The water in the pipes was boiled under the vacuum, thus extracting the heat from the structure where they were buried under the flooring. The vapour was piped to a heat exchanger where cool water from a cooling tower condensed the vapour into liquid that went back to the grid. In practice, both the heat exchanger and the cooling tower were combined into one Heat Rejection Unit. During the day, the system blocked the solar heat from the roof. At night, it extracted the heat stored in the whole structure.  This was the first tier of the three-tier cooling system. The second and third tiers were two separate mechanical cooling systems.

Tier 2
Medium temperature was set for meeting the sensible load only. This air was cooled to about 20°C using air-cooled ductable units and was distributed by insulated ducts placed above the false ceiling level. Since conventional systems had to be used and the required air quantity circulated, the cooling or refrigeration capacity of the units was in excess. Although this did not have an immediate installed cost benefit, the running cost is significantly lower due to its high evaporating temperature. The efficiency of this system is enhanced by the fact that the dehumidification is being taken care of by the third stage system.

Tier 3
A low temperature unit for fresh air and dehumidification cools the air to about 4°C. The system took in around 10% fresh air, mixed it with 10% of from the return air and dehumidified this mix – which was distributed using a Point-Of-Use air distribution network of insulated PVC pipes of low cross-section and terminated in adjustable outlets, much like those in an aircraft or luxury bus. This avoids inefficient air supply at 10°C at the ceiling being made to absorb the room load before it reaches the occupant at 22°C. The advantage of the fresh air distributed to the point of use is that it prevents its “dilution” with the rest of the recycled air being circulated by the medium temperature system, since the supply is within the occupants’ breathing zone.
The combined energy-efficiency of two tiers of this system is much higher, since the average evaporation is at about 15°C. The evaporation temperature of the single tier is anywhere between 2°C to 8°C, while the condensing temperature is the same. Since an air-conditioner pumps heat, its energy consumption is directly related to the difference in the condensing and evaporating temperatures.
 So, by applying techniques that have been used traditionally in our heritage structures, in tandem with modern technology, the load on the system was reduced and the structure was kept cooler than the human body . The energy saving was estimated to be between 30% to 40%, while the air quality within the breathing zone was improved due to higher oxygen level.

User: Fem Pharma, Nashik
HVAC Design: Surendra H. Shah
HVAC Contractors: Opal HVAC Engineers Pvt. Ltd.
Interior Design: Conrad Gonsalves