Modelling Study of a Novel Dual Heat Source Ammonia-Based Heat Pump System

Ammonia is considered as a promising alternative to address the escalating global warming challenges. This study introduces an innovative solar-assisted ground-source heat pump (SAGSHP) system that combines geothermal and solar heat sources while utilizing ammonia as the working fluid. To analyse the steady and transient thermal behaviours of multi-room buildings, the study was developed using a simulation model based on MATLAB/SIMULINK/ASPEN PLUS, which ensures the heat source to be switched flexibly between geothermal and solar heat. The intelligent control system maintains a constant room temperature at the setting point (22 ℃), providing adequate heating, cooling, and hot water while ensuring a comfortable and high-quality user experience. Compared to the ground-source heat pump (GSHP), SAGSHP significantly enhances the COP by supplementing solar energy and reducing pump work consumption. For instance, the COP that SAGSHP can reach is ~9, while that of GSHP is approximately 5. Additionally, SAGSHP can mitigate soil temperature and system performance degradation during prolonged operation in winter. Thu, this research demonstrates that the proposed SAGSHP system enhances heat pump efficiency and performance compared to conventional domestic heaters, with great potential to reduce carbon emissions in the domestic heating sector.