Computational modelling of a ground heat exchanger with groundwater flow

Abstract

Multiple layers of ground and the flow of groundwater in some layers have a significant effect on the cooling of vertical heat columns and heat exchangers. This paper investigates the important implication on the design of the Ground Heat Exchanger with regard to their heating effect. For this reason, a thermal model is constructed in COMSOL Multiphysics software and the effect of various parameters such as thermal conductivity of the ground and the groundwater flow velocity is considered. The model parameters were adjusted to present actual (known) parameters of an installed column and were validated against experimental values. The key for an overall capital cost reduction is the borehole length, where the results indicate that by using the groundwater available, construction of shallower Ground Source Heat Pump systems can be achieved with an increase of the coefficient of performance (COP).