Abstract
•A heat-source tower heat pump using subcooling heat for regeneration is proposed.•Three heating modes for heat-source tower heat pump are compared and discussed.•The novel system shows a nearly unreduced heating capacity with a high efficiency.
The heat-source tower heat pump, a frost-free heat pump with superior energy efficiency, has been used for heating in cold regions. Because the solution in the heat-source tower absorbs moisture continuously from the outdoor air and becomes diluted during heating, solution regeneration is necessary. However, existing regeneration technologies have various disadvantages, such as a reduced heating capacity, decreased system efficiency, or the need for additional equipment. Hence, it is urgent to develop a regeneration technology with low cost, high energy efficiency and little impact on heating capacity. In this study, a heat-source tower heat pump with a self-regenerator is proposed and experimentally investigated. To regenerate the weak solution in the tower, the system uses the subcooling heat of the refrigerant at the condenser outlet as a heat source. The operating characteristics of the system in three heating modes are investigated experimentally. The results indicate that in the heating mode with self-regeneration, the heating capacity of the system is similar to that in the heating mode without regeneration under the same operating conditions. The system realizes efficient regeneration and can operate continuously, although the system efficiency is 2.5–5.1% lower than that of a system without regeneration. In addition, the regeneration efficiency of the proposed system reaches 3.13–11.98 under the condition where the regeneration temperature ranges from 18 to 45 °C. These results demonstrate that the proposed system can be used in cold regions.