关键词: 土壤源热泵系统, 优化, 柱热源, 模型, 岩土热物性试验, 模拟退火算法, 数值模拟

Abstract:

Ground thermal properties is an important design parameter of ground-coupled heat pump system (GCHPs), and it can be decided based on the data from in-situ thermal response test (TRT). Considering that constant heat input can seldom be ensured in TRT, this paper presents a novel method for determining parameters of rock-soil thermal properties by using simulated annealing algorithm (SAA). In the method, Green function used in cylinder source model (CSM) of borehole heat exchanger (BHE) accelerates calculation of inlet/outlet water temperatures based on the TRT system model, and RMSE distribution overcomes the ill-posed problem of parameter identification in inverse heat transfer analysis, which puts into effect of SAA. In a calculation sample based on TRT of variable heat input, annealing temperature decreases with identified parameters reaching agreement with true value individually, and the relative errors of ground thermal conductivity and volumetric heat capacity are respectively 4.1% and 1.3% by comparing with the value calculated based on national regulations on the same in-situ measuring location. At the same time, the effective heat resistance of BHE can be obtained in the process of ASS. In general, ASS used in the variable heat power TRT is proved to be successful, and the study is helpful for the design of BHE in GCHPs.

Key words: GCHPs, optimization, cylinder source, model, rock-soil thermal response test, simulated annealing algorithm, numerical simulation