India can be in the forefront of the green building movement because of the inherent nature of Indian society but the biggest challenge to this possibility is the mindset of the people which needs to change if the movement is to succeed, Ashish Rakheja, Chairman Acrex India and Past President of the Indian Society of Heating, Refrigerating and Air Conditioning Engineers (ISHRAE), tells Renu Rajaram.
What is your outlook on green buildings?
As per IGBC (Indian Green Building Council) definition, a green building is one which uses less water, optimises energy efficiency, conserves natural resources, generates less waste and provides healthier spaces for occupants, as compared to a conventional building.
Green buildings offer enormous benefits such as operational savings in energy and water consumption, an enhanced environment and improved air quality for the occupants, yet help maintain the ecological balance at the same time. We need to promote this concept proactively and provide technical expertise and know how for conversion of existing structures into green buildings.
Given the resource shortage, how can sustainable building models be introduced in metros?
India can truly lead in the green building movement in the world because of the inherent nature of Indian Society and because our way of life is such. Right from the start we are taught to recycle all waste paper, glass, plastic etc. which are sold to kabadiwala (scrap dealer) and are recycled in various ways. Similarly, our homes are built around an aangan (courtyard), which brings light but not the heat. All our ancient monuments are as green as they can be. Therefore, if we learn to respect the Indian tradition and experience and blend these with modern technology, we will have the world’s greenest buildings at our doorstep with minimal extra cost burden.
What are the major challenges in the green building movement?
The biggest challenge is the mindset of the people, which needs to be changed. Green buildings are presumed to be expensive and green technologies inaccessible. The concept needs to be communicated to the grassroots level, and people have to be made aware that integrating green building materials into projects can tremendously help the environment. Furthermore, these materials can be reused and recycled.
Acrex India and ISHRAE have made significant contribution towards promoting this cause and we hope more people become a part of this movement. The solution is to disseminate as much information as possible about green technologies and products through expositions and events. It has to be proactively promoted by the manufacturers so that the end user realises the benefits of using these products.
What are some of the measures to save energy in buildings?
One can optimise a building’s energy use by appropriate use of daylight, glazing and shading mechanisms and natural ventilation. By focusing on the building envelope to effectively reduce the outdoor climate fluctuations and then finding the most energy efficient methods of transporting heating and cooling energy around a building is the key to energy efficiency.
How can the existing buildings be made more energy efficient?
In today’s time and age where resources are limited, we need to find such alternative solutions to increase building performance and make optimal use of the available resources. The process involves modifications to existing commercial buildings that may improve energy efficiency or decrease energy demand.
There are various steps one can follow to accomplish this; for instance, installing new-age energy efficient windows, tuning up the HVAC systems, installing LED bulbs, using BEE star rated air-conditioners and appliances, plugging air leaks etc. These are small initiatives even homeowners can take, thereby reducing the burden on the planet.
Tell us about efficient HVAC in green buildings.
In any building, nearly 60 per cent of the annual energy bill is on account of installed air-conditioning systems. As a start, the first attempt is to minimise heat gain into the building through internal loads from heat sources like lights, equipments and occupants, and through external loads from external sources like building envelope and infiltration of outdoor air. The building envelope is the interface between the interior of the building and the outdoor environment, including the walls, roof, and glass.
Building envelope is one of the major contributors of heat gain in a building; hence, for reduction of HVAC loads, it is crucial to optimise the envelope. HVAC equipment which is efficiently designed, increases comfort and reduces energy costs for occupants.
Can you discuss the energy consumption patterns by green rated air-conditioners?
Depending on their energy efficiency, air-conditioners are rated on a scale of 1–5. Higher the number of stars, the better is the energy efficiency of an air-conditioner. Star rating is based upon the EER (Energy-Efficiency Ratio) of an AC. While there is an initial investment to purchase the star rated air-conditioners, they are extremely cost effective in the long run as they help save on the running costs and thereby the operating costs of the AC.
As per data by BEE, a five star rated air-conditioner is 35 per cent more efficient than a one star air-conditioner and the payback period of incremental cost of five star rated AC over one star AC is approximately one year. Thus, an incremental price can be recovered in one year in the form of reduced electricity bill.