The amount of extractable heat with single U-tube in the function of time

Abstract

Heat pumps can be used for different purposes in building services. They obtain heat from the environment of lower temperature (e.g. air, water, earth) and transfer it into the building at a higher temperature. The heat of the ground can be the primary energy source of the heat pumps. We extract this heat with the help of ground heat exchangers. These exchangers are the U-tubes, which are either single or double. In our paper we deal with the problem of the extractable heat from the ground with these heat exchangers. We show a simple calculation method for the temperature change in the heat carrier fluid and for the overall thermal resistance of the U-tube.