蒸汽驱动的 CaCl₂ 吸收式热泵储热系统热力学性能研究

Thermal energy storage is an effective measure for deep peak-regulating operation of coal-fired combined heat and power units. In this paper, an absorption heat pump thermal energy storage system using CaCl₂-H₂O worker pair is proposed. CaCl₂-H₂O solution is used as the thermal energy storage medium, which significantly improves the thermal energy storage density by utilizing the concentration difference, large specific gravity, and absorption heat pump principle. Aspen Plus is used to simulate the system. At the design condition, the system has a thermal energy storage ratio of 0.446 and a thermal energy storage density around 30.34 kW·h/m³. At variable operating conditions, the driving temperature increases (208∼298^◦C), the thermal energy storage ratio decreases (0.461∼0.429), and the thermal energy storage density is around 30 kW·h/m³. Increase in evaporator outlet temperature (32∼50^◦C), decrease in thermal energy storage ratio (0.485∼0.397), decrease in thermal energy storage density (32.98∼26.96 kW·h/m³). When the condensing temperature increases (86∼98^◦C), the thermal energy storage ratio increases (0.414∼0.513), and the thermal energy storage density increases (28.22∼34.71 kW·h/m³). Similarly, when the preheating temperature increases (81∼93^◦C), the thermal energy storage ratio increases (0.414∼0.514), and the thermal energy storage density increases (28.20∼34.76 kW·h/m³).