Economic, Environmental, and Thermodynamic Analysis of a 200 °C High-Temperature Heat Pump System Integrated with a Flash Tank and Steam Generator for Industrial Steam Production Using Waste Heat

This study investigated a high-temperature heat pump for industrial steam production at 200 °C. Considering refrigerant thermal degradation at elevated temperatures, R1336mzz(Z) was selected because of its thermal stability. Two systems were analyzed: a flash tank (FT) cycle producing steam using a water valve and flash tank, and a steam generator (SG) cycle directly generating steam in the gas cooler. Unlike previous studies focusing primarily on cycle-level thermodynamic performance, this study systematically compares two steam production configurations for a 3 MW-class HTHP by considering heat pump–steam loop interactions and further evaluates their economic and environmental feasibility through LCC and LCCP analyses. Applying an internal heat exchanger reduced the operating pressure and increased the heat pump coefficient of performance (COP) by up to 13%, depending on the pressurized water temperature. In the FT cycle, lowering the valve outlet temperature from 180 °C to 150 °C increased the heat pump COP to a maximum of 3.06. However, the additional mechanical vapor recompression (MVR) power limited the overall system COP to 2.29–2.44. In the SG cycle, the system COP ranged from 1.94 to 2.54 according to the saturated water temperature at the gas cooler inlet, although operation at lower water temperatures approached the critical region, resulting in a narrower operating margin. LCC and LCCP analyses showed that replacing conventional boilers with heat pumps reduced operating costs by 26–59%, depending on regional energy prices, with payback periods of 2.27–8.76 years. Heat pump adoption also reduced life cycle climate impacts by 13–72%. These results demonstrate that high-temperature heat pumps can provide an economically and environmentally viable alternative for industrial steam production at 200 °C.