- Senior Lecturer Leena Thomas is part of a collaborative research project to develop a thermal comfort model for commercial buildings in India
- The model aims to offer an energy efficient, low-carbon development pathway for the sector, without compromising comfort or productivity
India may be one of the world’s fastest growing economies, but that doesn’t mean its greenhouse gas emissions need to follow suit. Senior Lecturer in the School of Architecture Leena Thomas explains how a collaborative research project involving UTS, India’s CEPT University and the University of Sydney is combining local knowledge with international research to create a unique thermal comfort model.
Over the last decade India has experienced an unprecedented rate of urbanisation with the building sector accounting for the largest share (47 per cent) of India’s final energy use between 1995 and 2005. Increased energy consumption has fuelled a 60 per cent increase in greenhouse gas emissions during the same period.
The mind-boggling projections for the future reiterate the energy intensive consequences of the built environment.
While Australia and other developed economies in the western world contend with a scenario where 80 per cent of the buildings that will be with us in 2050 have already been built, projections for India, by global management consulting firm McKinsey and Company suggest 70 to 80 per cent of the India of 2030 is yet to be built. And as that country shifts from 30 per cent (in 2008) to 40 per cent of its population living and working in urban areas by 2030, they forecast greenhouse gas emissions in Indian cities could increase to 1.6 billion tonnes of carbon dioxide equivalent (up from 230 million tonnes in 2005, and more than two-and-a-half times Australia’s net emissions in 2007).
While there are numerous social, political and economic forces that can explain these trends and influence the pace and nature of urban development, arguably the current trends in the Indian commercial office sector have much to answer for.
Why office buildings? Firstly, as the workforce shifts towards a service orientation that is office based, more people will spend more time in these buildings.
Secondly, from an energy perspective, air-conditioning in warm-to-hot climates represents the single largest energy end use in commercial buildings (approximately 50 per cent). And in a sector that is growing at the rate of 15 per cent of floor space per annum, this obviously requires urgent attention.
Thirdly, and perhaps most significantly, is the manner in which development in this domain is being pursued and valued. Together with shopping malls, the recent development of up-market office buildings is a visual symbol of globalisation and economic success.
Catch the metro to Gurgaon on the outskirts of New Delhi, or drive through the new technology parks in Bangalore or any one of India’s burgeoning cities, and you will see them – ‘clean’, un-shaded and extensively glazed buildings, with sealed windows and deep floor plates that require artificial lighting and central air-conditioning. Often they come fully kitted with mini power stations capable of 100 per cent power generation to combat the frequent electrical blackouts that plague many Indian cities.
In the absence of a thermal comfort standard specifically focused on India’s climatic and cultural context, the trend is to design air-conditioned office buildings based on a set of universally standardised comfort criteria – 22.5 degree Celcius plus or minus one degree Celcius. And here lies another point of concern – stipulation of such a narrow band of comfort mandates a very energy intensive (and expensive) solution for heating or cooling every time temperatures ride above or below this range. It forces a reliance on air-conditioning almost all year round – a condition which we have seen is highly addictive in western buildings.
One may argue these buildings are only developed for the top five to 10 per cent of the population. However, the look and feel of these buildings, and the expectation for stable comfort conditions that air-conditioning offers, permeates to residential living and goes on to influence the expectations, aspirations and consequent consumption of the next level of building occupants.
My research into post occupancy evaluations of buildings has developed a rich narrative of building performance in terms of their energy efficiency as well as the experience of the buildings from the users' point of view. It shows that understanding the social, or qualitative, dimension of occupants offers opportunities for a more sustainable future.
To date, most of the regulatory and research efforts to ameliorate greenhouse gas emissions from the building sector in India have remained in the technology domain. In other words, they focus on energy monitoring of exemplars for efficiency, and the development and promotion of remedial measures (such as high performance glazing, insulation and equipment) to deliver energy-efficient comfort. However, they do little to question or renegotiate the fundamental basis for the adopted comfort norms or to develop a better understanding of the expectations of occupants.
There is no doubt that buildings must be comfortable for their occupants. Admittedly, in countries like India, this is a challenge when temperatures range from 10 to 40 degrees in New Delhi or soar above 44 degrees in Ahmedabad.
However, the climate-rejecting approach currently in use is in stark contrast to a rich tradition of climate responsive architecture that the subcontinent has been noted for. This includes the evaporatively cooled and ornately shaded retreats offered by the step wells or vav in Ahmedabad, the jaali (lattice screen) and balconies for the self-shaded haveli in Rajasthan’s desert climate, and the veranda and airy courtyard versions of the tharavadu homes in humid Kerala.
There are also a significant number of built examples of climate responsive, contemporary workplaces in India such as Torrent Research Centre at Ahmedabad and the Institute for Rural Research and Development in Gurgaon. Often initiated as a partnership between the enlightened owner/developer and committed architect, these buildings use locally sourced materials and construction techniques. Environmental control is designed and achieved through passive means, sometimes in conjunction with alternate low-energy cooling systems which do not rely on refrigerant cooling. In other cases a mixed mode of operation, where supplementary air-conditioning is used only when conditions ride outside the acceptable comfort range, is set in sympathy with outdoor climatic conditions.
Our field studies on some of these sustainable and climate responsive buildings in India show they not only deliver low energy outcomes but also register an overall occupant satisfaction well above international benchmarks. Interestingly, they also indicate occupants in these buildings are actually tolerant of a higher range of temperatures when compared to western standards.
These findings begin to challenge the design approach and adoption of stringent comfort standards seen in the climate-rejecting new developments and an assumption that greater energy inputs translate automatically to improved occupant comfort.
Against this backdrop is the project to develop a thermal comfort model for the Indian climatic and cultural context for naturally ventilated and air-conditioned commercial buildings. It’s currently being undertaken in collaboration with the Centre for Sustainable Environment and Energy at CEPT University, Ahmedabad with funding from the Ministry of New and Renewable Energy of the Government of India.
Through post-occupancy evaluation and thermal comfort field studies of commercial buildings and their occupants, located across the climate zones of India, the model aims to offer an energy efficient, low-carbon development pathway for its commercial building sector, without compromising overall comfort or productivity.
In a developing country like India, where much of its built stock is yet to be developed and the efficient utilisation of resources is paramount, real game changers of this nature are needed to steer clear of the mistakes made in the energy-intensive western approach.
Faculty of Design Architecture and Building
Pics of jaali cladding and internal court supplied by Ashok B. Lall Architects