A new ground-coupled heat pump system integrated with a multi-mode air-source heat compensator to eliminate thermal imbalance in cold regions

•An economical hybrid GCHP system assisted by a multi-mode AHC is proposed.•The proposed system keeps soil thermal balance effectively in cold regions.•The AHC can fully absorb the heat in the air to realize seasonal energy storage.•The multi-mode AHC can also supply heat for space heating and DHW efficiently.•The energy saving rate of the proposed system is as high as 23.86%.

A ground-coupled heat pump (GCHP) is a clean and energy-saving approach to providing air conditioning and domestic hot water. For buildings with a dominant heating load, more heat is extracted from the soil and thermal imbalance becomes a crucial problem, in turn reducing efficiency and impeding the wide application of GCHP. Due to the disadvantages of the existing solutions, a multi-mode air-source heat compensator (AHC) integrated with a GCHP system to make a hybrid AHC-GCHP system is proposed in this paper. The principles and operating strategy of AHC-GCHP are illustrated in detail and its performance is simulated in the transient system simulation tool TRNSYS. AHC can not only compensate heat into the ground but also supply heat for space heating and domestic hot water in different modes through full use of the energy in the air with the average coefficient of performance (COP) ranging from 4.49 to 15.09. The AHC-GCHP system effectively keeps the soil thermal balance, and saves 23.86% energy compared with a traditional “boiler + split air conditioner” system, and costs less than half as much as a “hybrid GCHP assisted with solar collector” system. Consequently, the AHC-GCHP system is a potentially efficient and economic approach for buildings in cold regions.