Study on regeneration method of sodium formate anti-frost solution regenerator units using freezing concentration for heat source tower heat pumps

During the actual operation of the heat source tower heat pump(HSTHP), the mass fraction of the solution gradually decreases with the extension of operation time, leading to a decline in its moisture absorption capacity and an increase in freezing point temperature, which seriously impacts the heating capacity and stable operation of the HSTHP. Therefore, this paper proposes a sodium formate anti-frost solution regenerator unit using freezing concentration for the HSTHP. An experimental platform is built to test the regeneration performance of the unit under preset conditions. The regeneration performance and heat recovery capacity of the system are evaluated from three aspects: icing and separation, solute loss, and waste heat utilization efficiency. The results show that the unit can increase the mass fraction of the dilute solution from the initial 13% to the target fraction of 15% over 5 regeneration cycles, with an average separation ratio of 34.8%. After employing the solute recovery cycle, the solute recovery rate is 69.1%, and the proportion of solute loss is reduced to 3.1%. Throughout the process, the effective thermal utilization coefficient of the unit is 1.56, and the mass-energy ratio for ice removal is 0.332 kWh/kg, indicating good regeneration efficiency and high energy efficiency.