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

Authors: Paulo Canhoto, A. Heitor Reis, Antonio F. Miguel, Rui Rosa

Addresses: Physics Department and Evora Geophysics Center, University of Evora, R. Romao Ramalho, 59, 7000-671 Evora, Portugal. ' Physics Department and Evora Geophysics Center, University of Evora, R. Romao Ramalho, 59, 7000-671 Evora, Portugal. ' Physics Department and Evora Geophysics Center, University of Evora, R. Romao Ramalho, 59, 7000-671 Evora, Portugal. ' Physics Department and Evora Geophysics Center, University of Evora, R. Romao Ramalho, 59, 7000-671 Evora, Portugal

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 15°C, 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 Evora 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%.

Keywords: environment; exergy potential; heat pumps; performance improvement; air-groundwater exergy; energy savings; Portugal; environmental exergy; environmental heat sources; environmental heat sinks.

DOI: 10.1504/IJEX.2006.008323

International Journal of Exergy, 2006 Vol.3 No.1, pp.1 - 15

Available online: 04 Dec 2005

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