Regional Climate Effects on Optimum Configuration and Thermal Performance Parameters of BTES

Borehole thermal energy storage (BTES) systems significantly improve the efficiency of ground source heat pump (GSHP) systems and offer one of the best options to supply the thermal energy demand of buildings. The system’s performance is maximized by optimizing the configuration geometry of borehole heat exchangers (BHE). Regional climate determines the undisturbed ground temperature and the durations of charge and discharge periods. In this study, regional climate effects on the optimized thermal performance parameters are investigated. Configurational benefit factor (f_CB), charge benefit factor (Q^_CB), and storage efficiency (η) are calculated for two cities having opposite climatic conditions in Türkiye. For a concentric double-ring configuration geometry, the optimum values of inner and outer radii are determined by maximizing f_CB for the first five years. We found that f_CB practically insensitive to climatic conditions, and the optimum radii remain the same for both cities. In contrast, η is considerably affected (25%) by the climate conditions, while charge and discharge temperatures have no noticeable effect. Similarly, the climate effect on Q^_CB become significant (20%) for lower charge temperatures, while it is negligible for higher temperatures. The results show the sensitivity of the thermal performance parameters of BTES to climatic conditions.