Nature's very own retreat

Ravi Teja Sharma visits the TERI campus in Gual Pahari near Gurgaon, where the use of natural resources provides solutions for electricity, water and airconditioning.

A beautiful golf course precedes the entrance, and as you enter it is a completely different world from the precincts of Gurgaon inside the amazingly landscaped 36-hectare TERI (The Energy and Resources Institute) campus at Gual Pahari. Nestled inside this campus is an unassuming building called The Retreat. The building itself might not be a sight to behold, but once you know its features, we bet you can't ignore it.

"It's a sustainable building," says Pradeep Kumar, fellow, TERI. It contributes to the larger concept of sustainable development. He explains that conventional buildings use many resources.

"What we have done here is to build using minimum resources as well as take care that we do not pollute," he says. The complex saves 40-50 per cent of energy costs over conventionally designed buildings at an additional investment of only about 25 per cent.

One of the main aims here is to bring the overall energy demand down. To achieve this, TERI has used many passive concepts including the use of skylighting in rooms to maximise natural light usage.

From the double glazed windows heat gets blocked out while natural light continues to filter in. The walls too are insulated. The building itself is built facing the north and south, thereby minimising its interaction with sunlight (remember the sun rises in the east and sets in the west).

"These concepts help us keep the heating and cooling costs of the entire building very low," he adds.

Interestingly, the complex is not connected to any electricity grid. Here, the power is generated by photovoltaic panels (that are integrated into the building's roof so they don't look ugly) that capture the sun's energy and recharge a battery bank during the day, which is the main source of power at night.

And while the sun's energy is being captured during the day, a biomass gasifier converts firewood, dried leaves and twigs into "producer gas" which is used to run a generator producing electricity.

Integrated photovoltaic panels usually work for over 20 years and cost about Rs 4 lakh for 1 kilowatt. Standalone panels cost about Rs 2-2.5 lakh per kilowatt. The panels at The Retreat generate about 10 kilowatts of energy.

Specially designed skylights, energy-efficient lights, and constant monitoring here control the consumption of electricity. The entire complex can be lit up with less than 10 kilowatts; a comparable conventionally designed structure would require nearly 28 kilowatts to provide the same level of lighting.

The south block here comprises the living quarters with 24 single-occupancy rooms and six suites, and the north block has the conference centre with a large hall, a dining room, lounge, recreational facilities, and a library.

To cool or heat these, no airconditioning is used in the entire complex. Instead, everything again is sustainable and natural. The concept used for cooling is very simple (it is just that we never really think about these easier options). There are earth air tunnels four metres below the surface of the earth. Air is sucked and passed through this tunnel.

Remember, underground cellars are usually cooler in summer and warmer in winter. The naturally cooled air which passes through is then collected and distributed to the rooms through a huge fan room.

Along with this, effective insulation and shade provided by trees throughout the residential block ensure that the temperature in the complex remains more or less even all year round between 22° C and 26° C. The system has been augmented by adding chillers for dehumidification and additional cooling during the monsoon.

The only non-renewable source of energy used here is LPG, which runs a set of eco-friendly ammonia-based absorption chillers which are used to cool the conference centre, if required. Kumar informs that soon LPG should be replaced with fuel cells to run the chillers.

And for hot water through the day, 24 solar water-heating panels (inclined at 70 degrees instead of 45 degrees) provide up to 2,000 litres of hot water every day. So the living quarters have running hot water all the time and the air is never stale inside, thanks to the double chimney effect "" there is an air inlet as well as a way for it to get out.

Sustainable practices here would never have been complete without a thought given to recycling waste water. Here again, there are no huge structures to clean the water. Nature takes care of it all. Waste water is recycled by the "root zone" technique.

A bed of reed plants "" phrag-mytes (a member of the bamboo family whose roots have special capabilities to clean water) "" clarifies 5 cubic metres of waste water from the toilets and kitchen every day; the recycled water is used for irrigation. (You have to see the roses irrigated with this water!) More water is saved on a rainy day using methods to harvest and store rainwater.

While The Retreat is a perfect example of a building that uses natural resources, one can only hope that other places can follow the same path.