A fast distributed parameter model of ground heat exchanger based on response factor
Ground heat exchanger (GHE) is an important component of ground-coupled heat pump system. The soil temperature distribution and heat exchange capacity of GHE will largely determine the overall performance of the system. Consequently, it is very important for system design and its further performance improvement to seek a proper method of calculating the soil temperature field around GHE and the corresponding heat exchange rate. To break the limits of the existing calculating solutions and to improve the calculation accuracy and speed simultaneously, a fast distributed parameter model based on response factor (RF model) was proposed in this paper. The response factor refers to the contribution of a heat source to the excess temperature variation of a certain soil point. In a case study, the response factors and the temperature distribution of the soil heat container around one borehole were calculated using the RF model. Compared with results of numerical simulations, it can be known that the RF model equaled numerical solution in terms of accuracy, but enjoyed faster speed over numerical solution. In addition, the RF model was validated against the experiment data, with deviations less than 1.2%. In conclusion, the proposed RF model was a potential solution to predict the transient soil temperature distribution fast and accurately.