Library case study on green architecture

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Green architecture

Green architecture also known as “sustainable architecture” or “green building” is an approach to architectural design which emphasizes the place of the buildings with both local ecosystems & global environment.

It aims to create environmental friendly and energy efficient buildings. It entails actively harnessing renewable natural resources like solar energy and utilizing materials that cause the least possible damage to the global commons—water, soil, forests & air.

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Energy resource efficiency in new constructions can be effected by adopting an integrated approach to the building design. The primary steps in this approach are listed below :

1.Incorporate solar passive techniques in a building to minimize load on conventional systems (heating, cooling, ventilation & lighting).

2.Design energy efficient lighting and HVAC (heating, ventilation, and air conditioning) systems.

3.Use renewable energy systems (solar photovoltaic systems/ solar water heating systems) to meet a part of building load.

4.Use low energy materials and methods of construction and reduce transportation energy.

The dark colors on the thermo gram of a Passive house (right) show how little heat is escaping compared to a traditional building (left)

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Energy efficient construction techniques

1. Solar Chimney: A solar chimney often referred to as thermal chimney is a way of improving the natural ventilation of buildings by using convection of air heated by passive solar energy. A simple description of a solar chimney is that of a vertical shaft utilizing solar energy to enhance the natural stack ventilation through a building.

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The use of a solar chimney may benefit natural ventilation and passive cooling strategies of buildings thus help reduce energy use, CO2 emissions and pollution in general. Potential benefits regarding natural ventilation and use of solar chimneys are:

1. Improved ventilation rates on still, hot days2.Improved control of air flow through the building3.Improved air quality and reduced noise levels in urban areas

4.Increased night time ventilation rates5.Allow ventilation rates of narrow, small spaces with minimal exposure to external elements

6.Improved cooling during warm seasons7.Improved thermal comfort (improved air flow controls, reduced draughts)

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2. Wind catcher: A wind catcher is a traditional Persian architectural device used for many centuries to create natural ventilation in buildings.

The wind catcher functions on several principles: First, a wind catcher is capped and has several directional ports at the top (Traditionally four). By closing all but the one facing away from the incoming wind, air is drawn upwards using the, similar to how opening the one facing the wind would push air down the shaft. This generates significant cooling ventilation within the structure below.

In a windless environment or waterless house, a wind catcher functions as a stack effect aggregator of hot air. It creates a pressure gradient which allows less dense hot air to travel upwards and escape out the top. This is also compounded significantly by the day-night cycle mentioned above, trapping cool air below. The temperature in such an environment can't drop below the nightly low temperature.

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3. Trombe Wall: A Trombe wall is a sun-facing wall built from material that can act as a thermal mass (such as stone, concrete, or water tanks), combined with an air space, insulated glazing and vents to form a large solar thermal collector

Passive solar design using an unvented trombe wall and summer shading

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Modern Trombe walls have vents added to the top and bottom of the air gap between the glazing and the thermal mass. Heated air flows via convection into the building interior. The vents have one-way flaps which prevent convection at night, thereby making heat flow strongly directional. This kind of design is an isolated passive thermal collector. By moving the heat away from the collection surface, it greatly reduces thermal losses at night and improves overall heat gain.

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‘Hues of Life’ kakkanadu, kochi

Good Earth “Hues of Life” is a tropical high rise apartment building, a green alternative which responds to and takes advantage of the climate and the location.

Designed to accommodate 31 apartments with sky gardens, “Hues” is Good Earth’s foray into bio-climatic skyscrapers.

Details:1. 3 bedroom—20 units(2380 sq ft)

2. 3 bedroom—11 units(2080 sq ft)

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Highlights

• Sky-gardens in individual homes • Sky courts at intermediate levels as community spaces • Service core as a buffer area • The view exploited from all spaces. • Tropical landscape in the sky gardens and courts • Ground floor semi- open, connected to the outside • Air spaces and wind scoops • Continuous natural ventilation • Use of cavity walls for insulation • Natural day lighting, even in the deeper parts of the building • Use of natural materials • Sun and rain protection to the building by the provision of

large recesses, for windows and openings. • Reduced use of water and power resources. Lower

operational costs

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Interesting features

1. The individual sky garden: These are ‘green terraces’ with a breathtaking view in each apartment. The design of sky gardens minimize the heat & moisture on the lower flower, by virtue of protecting the wall below.

They are staggered on the alternate floors which enhance the air movement between the floors. It also acts as the buffer from dust, heat and lashing rain.

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2. The community sky court: The sky court  is a landscaped terrace designed in the transition areas around staircases and lifts, at intermediate levels, to act as a community space, and as visual relief.

A space for children to play, neighbors to meet, plants and lawn giving the air a fresher feel. The sky court is  designed to integrate hard and soft landscape, to create a variety of areas which encourage interaction among different groups.

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Wind scoop & natural light

The atria created by the sky court, act as wind scoops, drawing fresh air into them, and allowing hot air to escape, even through the homes. The same can be said for natural light, which penetrates to the deepest area of the building through them.

natural ventilationLarge openings have been provided on the windward and leeward sides, within the apartments, and cross ventilation is taken care of through the air spaces in the sky courts. The sky gardens in the apartments create air currents, drawing air into the house.

the service core

The service core is located on the south side of the building, and thus acts as the buffer from the heat, keeping the maximum heat gain away from the user space.

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Natural materials and cavity walls

For creating energy efficient and thermally comfortable spaces, a combination of hollow terracotta blocks and semi wire cur bricks have been used, for the external walls.

This forms a wall with three air cavities, the terracotta blocks on the outside and the bricks on the inside, keeping the interiors cool and bringing down the use of air-conditioning.

Besides serving as a passive coolant, the external wall is also very low on maintenance, bringing down the long term maintenance costs of the building.

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References 1. Energy-efficient buildings in India—Tata Energy Research

Institute (TERI)2. http://en.wikipedia.org/wiki/Image:Green_City.jpg3. http://www.goodearthhomes.net/HuesOfLife.html4.

http://en.wikipedia.org/wiki/Image:Passivhaus_thermogram_gedaemmt_ ungedaemmt.png

5. http://en.wikipedia.org/wiki/Sustainable_architecture