화학공학소재연구정보센터
Energy, Vol.169, 1090-1100, 2019
Pressure boost thermochemical sorption heat pump cycle
Drying is a common process in industries and usually discharges much waste heat. Heat pump is an energy efficient approach to upgrading waste heat to a higher drying temperature. In this paper, a novel pressure boost thermochemical sorption heat pump (TSHP) is proposed. Different from existing salt/ ammonia heat pump cycles, a compressor is installed between two reactors to drive the cycle so that only one sorbent is needed in the cycle and the exothermic process becomes continuous. Thermodynamic analysis shows that when desorption and sorption temperatures are 70 C and 120 degrees C, the COP (coefficient of performance) of the new cycle with working pair SrCl2/NH3 is 6.5, which is remarkably higher than that of conventional vapor compression heat pump (VCHP) cycle under same operating conditions. Furthermore, for higher temperature rise, a hybrid cascade heat pump cycle is proposed as well. The VCHP cycle with refrigerant R134a is selected as the low stage cycle, while the TSHP cycle with sorbent SrCl2 is chosen as the high stage cycle. For the evaporating temperature 30 degrees C and sorption temperature 120 degrees C, the cascade cycle COP is 2.4, relative to 2.0 COP of conventional vapor compression cascade heat pump cycle. (C) 2018 Elsevier Ltd. All rights reserved.