Computational and experimental performance analysis of a novel method for heating of domestic hot water with a ground source heat pump system

The paper presents a novel method developed for energy efficient heating of domestic hot water (DHW) with a ground source heat pump (GSHP) system. The method is based on step-based heating of DHW, where the DHW is gradually heated from the inlet temperature of domestic cold water to the target temperature of DHW using a specifically designed GSHP system concept. The developed method was tested and validated using experimental and computational performance analyses and the energy efficiency, operation and potential limitations of the developed application were also studied in existing apartment buildings. To demonstrate the efficiency of the developed application, the performance of the new concept was compared to the performance of a conventionally used GSHP system. The results demonstrated that the developed GSHP concept delivered up to 45-50% improvement in energy efficiency of the DHW heating process over the conventional GSHP application. The measured Seasonal Performance Factors were 2.5-2.6 for the conventional application and as high as 3.7-3.8 for the developed application, when DHW was heated from 7.5 °C to 55 °C. The case study demonstrated that the developed concept is also well applicable in existing buildings, but there is still room for improvement.