Dynamic simulation of ground source heat pump systems with nonstationary convolutions

Abstract

Advective processes related to groundwater motion and flow rates have a significant impact on the thermal performance of ground source heat pump systems. Including these elements during the design phase, however, remains a challenging task, as few computationally efficient modeling tools allow for their adequate and accurate representation. The present work addresses this issue by presenting the experimental validation of non-stationary convolutions for predicting the thermal response of a ground heat exchanger to both transient heat loads and advection. First, the method is outlined along with a simple demonstration case emulating the time-variation of groundwater velocity. Then, it is validated against experimental data retrieved from a 35-day multi-flow rate thermal response test conducted on a real standing column well. The results show a mean absolute error of 0.28 °C between the experimental and simulated results, which represents good accuracy considering the complexity of the thermo-hydro-processes at work. The high computing efficiency of the proposed technique is also demonstrated and suggests its potential for future implementation in common-use design tools.