Research Highlight

Cool it naturally

Subhra Priyadarshini

doi:10.1038/nindia.2008.123 Published online 19 February 2008

The roof-mounted solar chimney

© J. Mathur

Sun and wind are all you need to cool buildings, engineers in India have found.

Researchers working on the concept of a combined chimney and wind tower system have found that it can reduce the temperature of incoming air into the building by about five degrees Celsius. They developed the system for the annexe of Centre for Science and Environment, a typical urban institution building in New Delhi. The solar chimney based ventilation was introduced through roof mounted thermo-siphon air panels of 70 square metre absorber area. Openings for airflow inside the buildings were designed to suit smooth natural ventilation.

"The development of energy-efficient and passive cooling systems for buildings is essential from the point of view of environmental concerns and costs," says lead researcher Jyotirmay Mathur.

Conventionally, designers rely on natural ways to maximise comfort inside buildings. The team says this model of roof based ventilation and wind tower could provide a draft of air that could be turned into a passive cooling system.

The design involves a multi-storey wind tower clad with heavy stone panels which produces an upward draft of air drawn into the building passively and cooled by the massive tonnage of the stone classing. The air flows through the rooms and corridors accumulating heat. This is then carried to the top of the building and vented with large black, thermally conducting, panels providing a way to eject the heat quickly from the top of the building.

This cools down the building by several degrees and does away with the need for air conditioning. The model provides a cheap and natural design for sustainable buildings in urban settings.


  1. Mathur, J. et al. Design of passive cooling system for a building in composite climatic conditions in India. Int. J. Sust. Design 1, 110-126 (2008)