Saturday, March 24, 2012

Lessons From The Past

Award-winning architect Manit Rastogi, who designed the academy, explains that baoli -- the Hindi word for stepwell -- are bodies of water encased by a descending set of steps.

"When water evaporates in heat, it immediately brings down the temperature of the space around it," he says.

While traditional stepwells often go many stories below ground level, Rastogi's go down just four meters. However, the effect is the same and -- like the ancient Mughal palaces before it -- the academy enjoys its own microclimate.

Rastogi wonders: "How did they think up something so elaborate and yet so simple in its basic philosophy?

"How do you begin to think that you can dig into the ground and use the earth as a heat sink, have access to water, put a pavilion into it so that its comfortable through the year? It takes a lot of technology for us to think up something that simple now."

But it's not just the stepwells that are involved in this process of "passive cooling" -- the general term applied to technologies or design features that cool buildings without power consumption.

The whole building is raised above the ground on pillars, creating an airy and shaded pavilion that is used as a recreation and exhibition space. Here, according to Rastogi, the walls are made from a heat-absorbing material that creates a "thermal bank" -- so the warmth is slowly released at night when the temperature drops.

Centuries ago, latticed screens or "jaali" filtered direct sunlight into the palaces. The effect was decorative and helped reduce the heat. Likewise at The Pearl Academy, a latticed concrete screen runs the length of the building and provides a cooling outer skin.

"We've been able to demonstrate that good green building is not only cheaper to run; it's not only more comfortable to live in -- it's also cheaper to build," says Rastogi.

The success of the academy's eco-design has had an impact. Regulations -- based on these passive cooling techniques -- were introduced last year for all new Indian government buildings.
Ancient 'air-conditioning' cools building sustainably (CNN)

Architect Uses Ancient Techniques To Cool Modern Building in India (Treehugger)

Anupam Mishra: The ancient ingenuity of water harvesting (TEDTalks)

Urban planner and architect Manit Rastogi has an idea that makes the High Line look like child's play: turning the 350 kilometers of storm water drains -- now mostly filled with untreated sewage -- in Delhi into a network of landscaped paths for pedestrians and cyclists. If he can pull it off, India's capital will be greener, cleaner, and safer for its 17 million residents.
Despite their current stinky condition, the nullahs are in many ways ideal for such a transformation, having been built close to key sites in the city and being generally lined by lush, cooling vegetation.

In an article about Rastogi's concept of a "criss-crossed mesh of waterways, with boats plying and walkways, cycling paths, and parks on either side," the Indian daily Business Standard wrote that the system of canals and drains "connects most parts of Delhi so well that one could actually walk along a nullah from one point to any other distant part of the city without ever leaving the network."
Sewers as Sidewalks: Delhi Ups the Urban Reuse Ante (Treehugger)

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