Thermal performance and comfort assessment of U-shape and helical shape earth-air heat exchanger in India

Earth Air Tunnel Heat Exchanger (EATHE) systems are not so much popular in India because of restricted accessibility of ground space in majority of residential and commercial sector. In the present article, thermal performance of newly designed helical shaped EATHE system has been compared with conventional U–shaped EATHE system by keeping similar geometrical and operational configuration for the summer (April–June) and winter (December–February), respectively. In this regard, therefore, numerical model of both EATHE systems have been designed and experimentally validated. The thermal performance of both EATHE systems has been compared in terms of outlet air temperature and effectiveness. The present numerical study suggested that the newly designed helical EATHE system exhibits better thermal performance with lower ground requirement as compared to conventional U-shaped EATHE system. To evaluate the thermal comfort potential of EATHE system in office buildings of India, composite climate specific adaptive thermal comfort boundaries has been used. The detailed thermal performance behaviour of the EATHE system suggests that an additional 80% of the time; ambient air conditions became thermally comfortable during peak summer season. In addition, analysis of the results revealed that EATHE system has more potential during heating operation mode to maintain indoor comfort in winter season of composite climate in India.