Development of a Wet-bulb Temperature-based Heat Balance Control Method for a Hybrid Ground Source Heat Pump System

Abstract

Hybrid Ground Source Heat Pump (HGSHP) system has been widely used for mitigating the heat accumulation problem of conventional GSHP systems. This paper proposes a wet-bulb temperature-based control method for a HGSHP system which comprises a GSHP and a conventional water-cooled chiller (WCC) by using a cooling tower. With this method, the operation priority between the GSHP and the water-cooled chiller is determined according to the outdoor web-bulb temperature. A TRNSYS platform of the system is developed and simulations are carried out to investigate the system performance under the proposed control method. Meanwhile, simulations with two other control methods (reference methods), i.e., the GSHP-prioritized method and WCC-prioritized method, are also conducted. The study results show that the proposed control method has obvious advantage in controlling the heat balance of the ground source heat exchangers, and at the meantime no more energy is consumed when compared with the two reference control methods.