Performance analysis of integrated earth-air-tunnel-evaporative cooling system in hot and dry climate

Performance of simple earth-air-tunnel heat exchanger (EATHE) is enhanced by integrating an evaporative cooler at the outlet. Year round hourly analysis of the integrated system has been carried out for predominantly hot and dry climatic conditions using multiphase computational fluid dynamics (CFD) modeling with FLUENT software (version 6.3). The analysis has been carried out individually for all 8760 h of the year for the city of Ajmer (India), considering the temperature and humidity of ambient air as condition of inlet air. Results show that a simple EATHE system provides 4500 MJ of cooling effect during summer months, whereas 3109 MJ of additional cooling effect can be achieved by integrating evaporative cooler with the EATHE. Although the winter season in most of the cities in hot and dry climatic zones is very short, analysis of the 8760 h show that the EATHE system is capable of providing 4856 MJ equivalent of heating effect at such locations. For every hour, the condition of the outlet air has also been matched with the thermal comfort zone specified ay ASHRAE-55. Results show significant improvement in usefulness of the EATHE system when integrated with evaporative cooler in hot and dry climatic conditions. (C) 2011 Elsevier B.V. All rights reserved.