Evaluation of short and long-term performance of a dual-source heat pump

A dual-source heat pump is a heat pump coupled with two heat sources/sinks, such as the ground and the air. Such solutions allow to balance the thermal load to the ground, shifting part of the heating or cooling thermal load to the finned coil heat exchanger and preventing the possible degradation of the long-term ground-source heat pump performance. In addition, a similar configuration can be more economically convenient than a ground source heat pump. Depending on the plant configuration and the boundary conditions (mainly climatic area), the control strategy to switch between the two heat sources and sinks is crucial to ensure good heat pump performance in the short and long-term operation of the system. This work investigates a control strategy to choose the value of switch temperature, which establishes the most favorable heat source or sink to be used by the heat pump. A dynamic model is developed using TRNSYS to study and predict the thermal and electrical behavior of double-source heat pumps, which can be used in the context of retrofitted and new buildings under different weather conditions. The modeled system simulates an existing commercial building, where a dual-source heat pump is installed and whose operation data are monitored.