Journal of Korean Institute of Architectural Sustainable Environment and Building Systems ISSN:1976-6483(Print) 2586-0666(Online) 한국건축친환경설비학회논문집

A hybrid ground-source heat pump system has advantages of reducing initial cost of the ground-source heat pump and improving energy efficiency for the long-term operation. To effectively utilize the system, an appropriate control strategy is needed. This study thus investigated the performance of control strategies for a cooling tower assisted hybrid ground- source heat pump system. Three control strategies were analyzed: EWT-based FET, wet bulb temperature-based FTD, and schedule-based FRT. The building, the system and each control strategy were modeled by TRNSYS 18 and energy consumption by each control strategy were also calculated. The results showed that FTD strategy is the most effective in reducing energy consumption. Apart from the control algorithm, it was also found that in order to increase the efficiency of hybrid ground-source heat pump systems, it is helpful to increase the operating time of the cooling tower to reduce the proportion of the thermal load by the underground heat exchanger.