Performance analysis on a novel compact two-stage sorption refrigerator driven by low temperature heat source

A novel two-stage sorption refrigeration system is established and analyzed, which is driven by heat source with the temperature lower than 100 °C. CaCl2-BaCl2-NH3 is selected as working pair whereas matrix of expanded natural graphite treated with sulfuric acid (ENG-TSA) is used for the improved heat and mass transfer performance of composite sorbent. The non-fin filling technique is adopted to decrease mass and volume of sorption reactor, which further improves system compactness. Results show that two-stage sorption refrigeration system is flexibly adapted to different heat source with temperature below 100 °C. COP and SCP of the novel system range from 0.185 to 0.22 and from 50 W kg−1 to 76 W kg−1, respectively under the condition of 70 °C-90 °C heat source temperature and 5 °C-10 °C evaporation temperature. Performance of novel two-stage sorption refrigeration system is also compared with that of previous type by using the conventional fin tube sorption reactor based on mass and volume of the whole system. It is indicated that the highest improvement of SCPsys and VCPsys for the novel system are able to reach 28.1% and 32.5%, respectively when heat source temperature is 70 °C.