Improving the thermal performance of ground heat exchangers using triple helix arrangement

One of the efficient air conditioning systems is ground source heat pumps. The main problem of this type of pumps is the high cost of their installation. By choosing the suitable arrangement of ground heat exchangers, the number of piles and cost can be reduced by increasing the rate of heat transfer to the surrounding. In this research, the thermal performance of the ground heat exchanger with triple helix arrangement is investigated. To this aim, a three-dimensional transient CFD model of the ground heat exchanger and the surrounding soil is developed. In order to evaluate the performance, the results of the triple helix arrangement with the single helix arrangement were compared. In addition, the effect of two involving parameters, including helix pitch and diameter on the performance of the system is examined. The results show, by using the triple helix arrangement, the heat exchange rate is increased about 28% more compared to the single helical arrangement. It was found that the helix pitch has the greatest impact on the system performance and by reducing it, the system performance is improved.