STUDY OF A SINGLE PIPE BOREHOLE HEAT STORAGE BY MEANS OF AN ALTERNATE DIRECTION FINITE DIFFERENCE METHOD

Autor/autori: Bogdan HORBANIUC, Andrei DUMENCU, Michel FEIDT, Gheorghe DUMITRAŞCU,

Abstract: Borehole thermal storage systems represent a promising candidate for storing heat in the ground, thus making it possible to increase the efficiency of heat pumps used for residential purposes. Such a heat storage should store heat during the warm season of the year, returning it back during the cold one. It is of highest importance to know the performance of the heat storage in terms of heat charging and discharging rates. For this reason, the study of the transient heat transfer into the ground can provide very useful information about heat propagation rates and temperature distribution across the storage domain, thus allowing to determine at any moment the stored heat which might be available for use when required. The paper deals with the use of finite difference methods as a tool in determining the temperature field across a domain subjected to conduction heat transfer. The alternate direction technique is used and the temperature distribution and the stored heat are computed at each time step across a long hollow cylinder representing the ground heat storage. The results are presented and discussed for the charging phase of the storage.

Keywords: borehole heat storage, single pipe, finite difference, alternate direction implicit scheme, cylindrical geometry

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