Experimental investigation on the feasibility of a solution regenerator unit using freeze concentration for heat source tower heat pump system

Freeze concentration, which is often used in water treatment and the food industry, has a good regeneration effect and is easy for latent heat utilization. Therefore, a solution regenerator unit using freeze concentration with a heat pump system (SRFCHP) is proposed in this paper. In winter, SRFCHP can achieve weak antifreeze solution concentration, and the heat capacity of frozen phase transition is used to raise the supply water temperature. To investigate the performance of the SRFCHP system, a test was built in the enthalpy difference laboratory. Results shown that the SRFCHP system was able to regenerate the dilute solution from 13 % to 15 % in five regeneration cycle cycles. Around 34.5 % of ice production was able to be separated and the average loss mass of solute was about 0.95 kg per test in the regeneration cycle. Moreover, the SRFCHP system has a better performance on energy efficiency. About 62.5 % of total heat capacity had been recovered effectively. The solute recovery rate was 69.1 %. The coefficient of performance of refrigeration efficiency and heat recovery efficiency were 2.01 and 3.01, respectively. The specific ice production rate was 11.03 kg/kWh. These results demonstrate that the proposed system can be used in frosting regions to regenerate the dilution liquid.