Performance optimization of high-temperature heat pump system for staged heating under large temperature span

Abstract

With the rise in the widespread application of high-temperature heat pump (HTHP) systems, the system temperature across the large volume, high condensing temperature, and sink unbalanced proportion of heat supply, and other characteristics of the HTHP system need to be optimized as the primary solution. To improve the thermodynamic performance of the system at high temperatures across the process, the effects of the intermediate cooling structure circulation mode and hierarchical heating on the HTHP system were analyzed in this work. Furthermore, the HTHP system was optimized by adjusting the appropriate diversion coefficients in order to improve its coefficient of performance (COP). The optimum value of COP and the corresponding coefficients of diversion for the different process requirements were calculated using R245fa as the refrigerant and perturbing the coefficients of diversion in combination with a simulated annealing algorithm. When the condensing temperature was between 120–140 °C, the COP of the optimized system was observed to be 15.93–20.48% higher than that of the traditional two-stage compression system, and the system was found to exhibit a significant unit heat production and refrigeration capacity.