Abstract: In order to achieve freezing condition under -15 °C while the heating source temperature is lower than 100 °C and the condensing temperature is higher than 30 °C, a C_aCl₂-B_aCl₂-NH₃ adsorption refrigeration system was designed with two-stage desorption cycle. A series of experiments were performed on two-stage adsorption test unit in order to get the adsorption and desorption data of the composite absorbents, which are the mixture of salt chloride and expanded graphite. By fitting the data into adsorption and desorption curve, we set a mathematic model of the system by combining the adsorption and desorption equations and heat transfer equations of the system. The performance of the system was simulated and the results show that the system is able to use 85 °C heating source for the output of -15 °C freezing temperature, when the condensing temperature is 30 °C. The cooling capacity of the system simulated is 2.62 kW.

Key words:  calcium chloride, barium chloride, two-stage adsorption refrigeration, low temperature heat source, simulation