Feasibility study on the optimal design method of ground-water source hybrid heat pump system applied to office buildings

In order to reduce the energy consumption of buildings, a ground source heat pump (GSHP) system was introduced to reduce the building energy consumption. However, general GSHP systems are not as popular as photovoltaic and thermal systems owing to soil imbalances and performance degradation during long-term operation. To solve this problem, we propose a ground-water source hybrid heat pump (GWHP) system. GWHP systems can simultaneously use ground and water sources to avoid soil imbalance and degradation. In this study, we proposed a GWHP system and investigated its feasibility as a replacement for a GSHP system in terms of performance and heat source temperature. In addition, an optimal capacity design method for the GWHP system is presented to evaluate its economic feasibility. The performance and economic analysis show that the cooling and heating performance of the proposed GWHP was 15 % and 3 % better, respectively, compared to the existing GSHP system. Our results also showed that the proposed design method was approximately 5.3 % less expensive than the existing GSHP systems. The GWHP system could be a suitable alternative to the GSHP system, as confirmed by both the energy simulation and cost analysis.