By Shashikant Pawar,
‘Earth provides enough to satisfy every man’s needs, but not every man’s greed’, said Mahatma Gandhi. When we ponder upon this statement, we understand there are many aspects implicit in it-progressing while living in harmony with nature, respecting rights of the present and future generations etc. We find similar ideas echoed in the United nations 2030 agenda for sustainable development goals which revolve around people, planet, prosperity, peace and partnership. ‘Sustainability’ is a comprehensive term. It has three primary dimensions: the economic, social and environmental. Therefore, it is important to keep in mind these aspects while adopting new products, utilities or services having advanced technologies. It becomes all the more important for engineers and technology leaders to consciously design the newer products and technologies such that they are sustainable. Sustainable building design is one such area on which we shall focus our attention to in this article.
We are attracted to the malls and commercial buildings with dazzling glass panes on all sides due to the aesthetics. However, for tropical countries like India, this design becomes the source of additional thermal load on the central air conditioning system, especially in summer, when the maximum temperature in many places easily cross 40 degree Celsius. During the daytime, the shortwave solar radiations pass through the glass panes and heat the interior. The heated interiors start emitting the longwave thermal radiations which cannot escape through the glass and get trapped inside. The thermal radiations get reflected off the glass walls, roof etc. and heat the inside air. This essentially is the ‘Greenhouse effect’ which we often experience when we park our cars in the sunshine for a longer time. A simple solution many of us know is to keep the car doors open for some time and let the heated air go out before switching on the air conditioner. In the scenario wherein almost 50% increase in the energy consumption worldwide has been predicted for the period between 2018 and 2050, and in hot-humid climates, cooling systems contribute to about 65 to 70% of the electricity consumption in air-conditioned malls, naturally ventilated open-air malls designed according to the local climatic conditions can reduce the energy consumption significantly.
The Rajkumari Ratnavati girl’s school with a capacity of 400, built in the kanoi village of Jaisalmer district, Rajasthan is one of the recent examples of sustainable building design. It is an ‘Oasis’ in the Thar desert in every sense of the term. The school was conceptualized by CITTA founder Michael Daube, and designed by US-based architect Diana Kellogg. The building uses locally available yellow sandstone which due to its properties of higher heat capacity and porosity, cools down during night. The air coming in its contact during the daytime is thus cooled, and creates the thermal comfort. The oval shaped building has open courtyard to promote natural ventilation which serves as the play area for the kids. The solar panels on top of the building work as a canopy providing shade while simultaneously providing the electrical energy for the building.
In India the sustainable design of the buildings are promoted by the green building awards. The predominant green rating frameworks in India are GRIHA (Green Rating for Integrated Habitat Assessment), IGBC (Indian Green Building Council), LEED (Leadership in Energy and Environmental Design), and BEE (Bureau of Energy Efficiency). Typically, the buildings undergo a verification and review process and are awarded points. According to these points they get Silver, Gold or Platinum rating. ITC Green Centre, Gurgaon, Suzlon One Earth, Pune, Patni
Knowledge Center, Noida, Cisco Building, Bangalore, Indira Paryavaran Bhawan, New Delhi are some of the projects which have received the Platinum rating.
As mentioned above, engineering design should cater to many other aspects apart from just the functionality, if it has to be sustainable. One of the approaches to achieve this is to study the natural systems of similar utility, carefully, and mimicking them. Bio-inspired designs are therefore gaining more importance nowadays. The design of a shopping center and commercial office block, Eastgate Centre in central Harare, Zimbabve, by the architect Mick Pearce is a classic example of design of natural ventilation of the building inspired by cooling system of termite mounds.
In summary, living in harmony with nature sustainably, which is the theme of world environment day 2022, requires a much larger perspective than the traditional engineering problem solving approach and we all must gear up this new challenge by becoming more adaptive and open.
(The author is a faculty, Plaksha University. Views expressed are personal)