Study on application potential of seasonal thermal energy storage-hybrid ground source heat pump in Taiwan-Taking experiments in Tainan as examples

Ground source heat pumps (GSHPs) are widely used in building energy conservation in many countries and regions. However, they are rarely seen in Taiwan. The main reason is the extraordinary imbalance between the heating load and cooling load of buildings in Taiwan. Hybrid ground source heat pump (HGSHP) is a hybridization of a traditional GSHP system, and can effectively balance the heat injected into and extracted from the ground over an annual cycle. This study focuses on the application of seasonal thermal energy storage HGSHP (STES-HGSHP). Based on the data of six experiments in Tainan, Taiwan, this study finds out the ways to make the process of cold energy storage run with high efficiency, including (1) increasing the flow rate in the ground coupled heat exchanger (GCHE); (2) using double-U GCHE instead of single-U GCHE; (3) starting the process of cold energy storage at the time with low wet bulb temperature; (4) storing more cold energy than necessary in order to lower the ground temperature. Finally, by analyzing the level of wet bulb temperature in winter, this study confirms that the application of STES-HGSHP has great potential in Tainan.