Dampening of fluctuations in groundwater temperature by heat exchange between the aquifer and the adjacent layers

Heat storage in aquifers is attractive from the point of view of energy conservation. However, the influence on the chemical and microbiological composition of groundwater is insufficiently known. The nature and the extent of this influence can best be studied in the field. An understanding of the transport of heat in the aquifer will be indispensable for the planning of field experiments. For this purpose several aspects of non-steady and periodic heat transport are discussed, with special attention to the heat exchange between an aquifer and its adjacent layers. As in the case of steady heat transport, the changes of the temperature around an injection well can be expressed as a function of the retention time of the injected water. Hence, the heat flow pattern can be found by the calculation of groundwater streamlines and retention times.