Earth Air Pipe Heat Exchanger for Thermal Comfort

Earth Air Pipe Heat Exchanger (EAPHE) are long pipes that are laid under the ground having one end open in air and the other one connected to the air intake of buildings. An analytical solution has been derived by considering the fundamental equations of energy, heat transfer and psychometrics, for predicting the temperature of air and relative humidity at the outlet of EAPHE. Parametric studies performed for the EAPHE coupled with and without the evaporative cooler. In both the cases, i.e. EAPHE with and without evaporative cooling, performance of the system has been further analyzed for various individual hours spread over entire year using two-phase CFD model. The analyzed integrated system is considered to have capacity of operating as simple EATHE, simple evaporative cooler, and combine EATHE-evaporative cooler through valves and dampers depending upon conditions of ambient air. Year-round hourly analysis of EATHE system showed that even in a predominantly hot and dry climatic location (Ajmer), where space heating requirement arises only for about 4 months in a year, usefulness of simple EATHE is more in winter season than summer season.