Abstract:In view of the fact that there are many low-grade hot water in smelters in the mining industry, such as cooling circulating water of equipment and underground water inflow in mines, in this study, the single-stage and two-stage vapor compression heat pump systems for waste heat recovery is compared, and a calculation model of the thermal performance of the system is developed. Then the energy efficiency of the two systems is compared. The results show that the performance of the two-stage vapor compression heat pump system (TS) is better than that of the single-stage vapor compression heat pump system (SS). When the hot water inlet temperature is 85℃ and the outlet temperature is 115℃, the COP of the TS system is increased by 22.60% compared with the SS system when the hot water inlet temperature is85℃ and the outlet temperature is 115℃, and the COP of the TS system is increased by 21.07% compared with the SS system when the isentropic efficiency is 0.7.