What is a Green Building?
Any building which conserves natural resources, optimises energy efficiency and provides healthier spaces, uses less water and generates less waste is categorised as a green building which are rooted in rediscovery of Indian ethos through Panchabhutas – the 5 elements of nature by adopting relevant engineering practices pertaining to each element as follows;
Earth – Site Selection and planning
Water – Water Conservation
Fire – Energy Efficiency
Air – Indoor Environment Quality
Sky – Daylight, Night Sky pollution.
How do Green Buildings achieve sustainability?
Green Buildings ensure sustainability by recognizing performance in following key areas:
- Site Selection and Planning,
- Water Conservation
- Energy Efficiency
- Building Materials and Resources,
- Indoor Environment Quality.
Sustainability can be achieved by using resources to meet our needs without depriving the future generation of these resources. Even though external appearance wise and use wise, both green buildings and conventional buildings are same, the difference lies in operational savings from day one, conservation of natural resources and human comfort, productivity and clean indoor environment.
The tangible benefits of Green Buildings are reduced operating costs, optimised lifecycle economic performance, energy savings of 30-50%, water savings 20-30% and reduction in initial investment. Intangible benefits of Green Design are reduction of impact on environment, enhanced occupant comfort and improved productivity of occupants.
What does a Green Building do differently?
Use of new technologies or products, for example – waterless urinals, root zone treatment systems, light pipes, widespread use of flash blocks, insulated walls, roof glazing, low emitting materials- paints, sealants, adhesives etc. using simulation for energy/lighting.
Let us now understand how a green building addresses the 5 elements of nature.
1. Earth – Sustainable sites, built around the environment preserving the trees and hills in their natural state, reducing heat island effect by using roof material of high reflective paint, vegetative roof, green walls etc.
2. Water – Achieving water efficiency through Rainwater Harvesting, Phyto Remediation (aeration using plantation), Xeriscaping (landscaping that does not require permanent irrigation system) use of Low Flow Fixtures, onsite STP, enhanced Irrigation System, Water Metering Systems, Water Efficient Landscaping, Maximise Tree Plantation, planting native trees. Potable water needn’t be used for gardening, air conditioning systems, boiler feed water, flushing etc.
3. Fire – Energy Efficiency achieved through proper orientation (minimise exposure of buildings on south and west side), adopting envelope measures like wall glazing, fenestration, shading, sky lighting roof. Adopting energy efficient equipment and systems for air conditioning, lighting, pumps, motors, VFD, controls of temperature, humidity, BMS.
4. Air- Maintaining indoor air quality is one of the prerequisites for good health of occupants. People are liable to fall sick if Indoor air quality is not up to the mark. Building starts showing sick building syndrome when CO2 concentration is greater than 1000ppm and symptoms persist in more than 20% of occupants. The sources of Indoor pollution are tobacco smoke, outdoor air, HVAC system, stagnant water, humidifiers. Indoor plants are very helpful in reducing pollution. At least one plant in every 100sq ft. space is helpful. Money plant, peace lily, areca palm etc are very efficient in reducing pollution.
5. Day light – Proper indoor illumination helps in minimising electrical consumption. Proper connectivity should be provided between interior and exterior spaces to achieve visual daylight which helps in energy saving and demand reduction.
By proper arrangement of windows, planning of rooms, daylight factor can be improved. Optimisation of light quality can happen through reduction of glare, proper luminance ratios, daylighting, redirecting daylighting, energy efficient lighting.
Sustainable Architecture Design
- Orientation of building with respect to movement of sun.
- Most preferred orientation of building-Long Direction- North South.
- The lesser surface to volume ratio the better.
- Solar heat gain coefficient – Solar Heat passing through glazing/Total incident solar radiation. The lesser it is the better it is design wise.
- Visual Light Transmission (VLT) – Higher VLT means higher daytime penetration which helps in reducing energy consumption. It is always desirable to have higher VLT.
- Window Wall Ratio – Total fenestration area /Gross Wall area. Higher Window Wall ratio minimises necessity of daytime illumination of rooms.
Efficient HVAC system and controls
- Design of optimised temperature set point
- Use of high efficiency chillers
- Variable frequency drive for AHUs and Chillers
- Piping and duct insulation
- Personalized thermal control
- Proper system balancing
- Avoid oversizing of equipment
- Link thermostat with occupancy sensors
- Use of set point 25 degree Celsius for AC
Why Green Buildings?
Basic construction material of any building are cement, steel, glass, bricks, wood, sand, stones etc. Inputs required to manufacture basic construction materials are ores, minerals, wooden logs etc. Electricity required to generate these raw materials are Fossil fuels like coal, oil and gas.
India’s oil reserves will last 18 years at current rate of production and we shall run out of iron ore in 28 years. Coal reserves will last for 80 years. Global deforestation is happening at 13 million hectares every year. At this rate, construction of conventional buildings shall be no more sustainable. In our country urbanisation is happening at 5.8 million per year. Demand for electricity is increasing by 85%. World population is expected to reach 9.7 Bn by 2050 resulting in increased requirement of habitation. Buildings are responsible for 40% energy consumption and 36% C02 emission. Our responsibility is to proceed in a way that will sustain life which allows our next generation to survive and meet their needs. Hence Green buildings are not just an option but a necessity now.
Growth forecast of commercial buildings in our country is 1900 million sqm by 2030. Building lifecycle cost is 5% at conception, 20% during construction and 75% during operation and maintenance, hence maximum weightage of green buildings is on energy efficiency since 70% of our energy is from coal plants.
Green building concept started at USA in 1990 by World Green Building Council. CII Sohrabji Godrej Green Business Centre at Hyderabad is the first Platinum rated Green Building and a Net Zero Energy Building in India covering an area of 20,000 sqft. constructed in 2003.This pioneering effort was followed by construction of ITC Green Centre Gurgaon covering 1,70,000 sqft. In 2004, Wipro Building in Gurgaon in 2005 covering 1,75,000 sqm and the list is endless. The various ratings of Green Buildings like Platinum, Gold etc. are being awarded by reputed certification agencies like IGBC, GRIHA, LEED, GEMS etc.
Our organisation L&T is contributing immensely to this Green Building Movement. Majority of our campuses are certified as green campuses thus reducing the overall carbon footprint which shall be a great contributor to our country achieving carbon neutrality before the targeted date of 2070. At 26th session of the COP in Nov 2021, India has pledged to achieve the target of net zero emissions by 2070. Green Buildings shall undoubtedly be significant contributors in achieving this milestone. It is high time to ensure that all new buildings /complexes coming up in our country are Green Buildings since it ensures that operating costs are reduced, optimises life cycle economic performance and are undoubtedly the best option to achieve carbon neutrality.
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