Utilisation of air-groundwater exergy potential for improvement of the performance of heat pump systems

Abstract

This paper reports a study on the use of the non-flow air-groundwater exergy potential for improving heat pump performance. It is shown that for air/groundwater temperature differences of order 15ºC, energy savings up to 50% may be expected for heat pumps operating either in the heating mode or in the cooling mode. It is also shown that the reduction in the energy required to drive the heat pump is proportional to the square root of the exergy potential. In the Évora region the exergy potential peaks during wintertime and during summertime. It is concluded that the use of the non-flow air-groundwater exergy potential is attractive either for heating purposes in wintertime, when energy savings can reach 20%, or for cooling purposes during summertime when they can reach 10%.