The use of earth-air heat exchanger for improving building comfort conditions in the tropical climate

Tropical climate is characterised by high ambient temperatures and solar radiation, a combination of these factors causes thermal discomfort in buildings. The common approach to maintaining comfortable thermal environment in buildings in such climates is using mechanical air-conditioning systems. High energy demand is needed to operate and maintain these systems continuously over long periods of time. With the rapid increase in population and economic growth of countries in the tropical regions, it is becoming inevitable that passive and low energy strategies must be used as suitable alternatives. Earth-air heat exchanger (EAHX) is a subterranean ventilation system that explores soil temperature below the surface to pre-cool or pre-heat ventilation air. Performance of EAHX varies with climatic and soil condition of the area. Climatic and soil parameters affecting the thermal performance of EAHX has been determined for Tropical climate of Nigeria. Thermal simulations have been carried out using Transient System Simulation Environment (TRNSYS) to evaluate the cooling energy gain and the reduction of ambient temperature extremes. The results show that the system can be used to improve comfort conditions and reduce building cooling loads.