Shelter is one of the fundamental needs of human beings. The need to own a place for living is also seen in animals and birds. In the beginning of human civilization man used to live in caves and on trees, gradually he has identified materials suitable for construction like clay, stone and timber. Basic purpose of these dwellings is to protect man from weather and predators. These houses made way for larger inhabitations like castles, forts and palaces which had built in mechanism for providing sunlight and fresh air. As the time went on, man with his knowledge invented latest technologies and materials which helped him in construction of different types of buildings. These buildings and the materials used for construction brought rapid changes in the environment. Limitation of space, growth of population and rapid urbanization lead to community dwelling culture which increased problems like CFC emissions, insufficient ventilation, increase of waste materials during construction and maintenance of house arouse.
It is found that the building industry will consume 40% of total global energy and release about 3800megatons of CO2 into atmosphere. They have harmful impact on the nature. According to a report the building industry has following impacts:
Consumption of 40% of world’s total energy.
Consumption of 30% of raw materials.
About 25% of timber harvest is going down.
35% of CO2 emission.
16% of fresh water is being depleted.
40% of municipal solid waste is being generated.
50% of ozone depleting CFC’s are still in use.
30% of the residents have sick building syndrome.
The above issues have forced man to think along the terms of sustainable development which gave solution for his problem through “green building” concept. Most of the people think that it is latest technology which has been invented in recent times. But a very few people know that this concept is being used since time immemorial. The Hawa Mahal in Jaipur Rajasthan in India is constructed in such a way that it has natural ventilation which is also one of the principles of green construction. Similarly many buildings were constructed using different principles of green construction unknowingly the concept.
A Green Building is the one whose construction and life time operation provides healthiest possible environment having the most efficient and least disruptive use of the land, water, energy and resources. Green Building is the one that preserves and restores the habitat which is vital for sustaining life by reducing negative environmental impact. Construction of Green Building minimizes on-site grading, saves natural resources by using alternative building material and recycles construction waste rather than dumping in landfill. Green Building’s interior spaces have natural lighting, outdoor views while highly efficient heating, ventilating and air conditioning (HVAC) systems and low volatile organic compounds like paints, flooring and furniture create a superior indoor air quality. Most of the Green Buildings are designed according to LEED (Leadership in Energy and Environmental Design). Green Buildings are more comfortable and easier to live with due to Row operating and owning costs. It is estimated by the year 2050, residential, commercial and institutional buildings consume about 38-40%global energy and release3800-4000 mega tones of carbon in to the atmosphere. Climate change by itself can also precipitate lager energy demand as people seek greater comfort levels in more extreme conditions (2, 3).
NEED FOR GREEN BUILDINGS:
The environmental impact of building design and construction industry is significant. Buildings consume more than 20% of electricity used in India.
Normal construction deprives land usage from natural biologically diverse habitats.
Green Building practices can substantially reduce or eliminate negative environmental impacts and improve existing unsustainable design, construction and operational practices.
As an advantage greendesign measures help in reducing running costs and mitigate indoor air quality problems.
Studies conducted on green buildings reported productivity gains up to 16%.
As a matter of fact green building enhances environmental and economic benefit for occupants.
PLANNING AND CONSTRUCTION OF GREEN BUIDING:
It is very important for careful planning before a Green Building project is started. Though building green house does need to be expensive or time consuming, final choice of type of green building will depend on the space desired, home architecture, available site and costs. Green building should be located in such a place where there is maximum sunlight. The first choice of location is either south or south eastern side. Sunlight all the day is best for proper lighting of the house and growing trees like maple, oak, neem and tamarind can efficiently shade the Green building from intense late summer afternoon. Good drainage system is another important requirement for the site. The Green building should be built above the ground level so that rain water and irrigation water will drain in to the soil. Evolve strategies to stockpile top soil for landscaping purpose. Consider adopting measures such as temporary and permanent seeding, mulching, dykes, silt fencing, sediment traps and sediment basins where ever required. Open areas can be landscaped and paved areas can be developed with permeable paving. For impermeable surfaces like concrete surfaces direct entire runoff towards storm water collection pits.
It is necessary to select a site which is nearer to all basic amenities like grocery store, pharmacy, post office, police station, hospital, railway station, bus station. Site should have provision for parking and open space for growing plants.
Heat Island effect: Precautions are to be taken to reduce heat island effect i.e., thermal gradient differences formed between heat developed and undeveloped areas to minimize impact on micro climate. Typical materials with high reflective properties like china mosaic, white cement tiles and paints should be used for reducing heat island effect.
Reduction of water consumption and protection of water quality is other important factor for Green building. The conservation and protection of water throughout the life of a Green building can be accomplished by designing for dual plumbing that recycles water in toilet flushing. Waste -water may be minimized by using water conserving fixtures like ultra low flush toilets and low flow shower heads. Bidets may be used to reduce the usage of toilet papers, reduce load on sewers and increasing possibilities of reusing water on-site. Water treatment is a must for maintaining water quality. Usage of grey water for growing plants will also helpful for water conservation. There should be provision for rain water harvesting systems. Water efficient fixtures are to be used to minimize indoor water usage.
Rain Water Harvesting System :
Reuse of harvested rain water in plumbing systems in commercial or residential setting proves to be environmentally and economically effective. It can reduce usage of drinking water for other purposes. In this system runoff water can be harvested from roofs via down pipes that are connected to water reservoirs and under ground tanks. It will be easy to install this system for new dwellings with down pipes at one end and a cellar with a place for a low cost tank at other end. The harvested water can be used for washing clothes and toilet flushing.
The factors to be considered while designing rain water harvesting system are:
Size based on average availability and consumption.
Materials of cistern.
Suitable location .
Basic Components :
o Catchment Area
o Gutters and downspouts
o Leaf screens and roof washers
o Conveying systems
o Treatment of water.
Operation And Maintenance of Harvesting system:
• Cleaning must be done at beginning of summer and winter rainfall to remove any foreign material.
• Filtering and distribution system should be maintained.
• Filtration is essential to prevent entry of contaminants.
• Preferred height of distribution line should be 30.48cm above bottom of tank or reservoir
Water Efficient fixtures:
These are used to reduce indoor water usage. The water fixtures which are being used should be efficient. Fixtures are available with ultra high efficiency which can reduce substantial quantity of water consumption.
ENERGY EFFICIENCY :
Green buildings are also useful to reduce energy consumption. Higher performance buildings use less operating energy. Studies such as U.S. LCI Database Project(6) show buildings built primarily with wood will have a lower energy than those built with brick, concrete or steel(7). Usage of high efficiency windows and insulation in walls, ceiling and floors increase the efficiency of the energy envelope. Passive solar building design can also be used in low energy homes. Designers orient windows and walls, porches and trees to shade windows and roofs during the summer while maximizing solar gain in the winter(8). Apart from this proper window placement can provide more natural light and lessen the need for electric lighting during the day. Providing proper metering also saves energy. Solar water heating also reduces energy costs. Onsite generation of renewable energy through solar, wind, hydro or biomass energies can significantly reduce the environmental impact on the building.
Energy saving measures in various equipments:
To conserve energy we can use following equipment
1) Level controllers in overhead water tanks.
2) Energy efficient lifts.
3) Minimise 60% efficiency in water pumps
4) Minimise 75% efficiency in motors.