A two-stage deep freezing chemisorption cycle driven by low-temperature heat source

A two-stage chemisorption cycle suitable for deep-freezing application driven by low-temperature heat source was proposed. Through two-stage desorption processes, the two-stage cycle can break through the limitations of the heating temperature and ambient cooling temperature. The two-stage cycle based on CaCl2/BaCl2-NH3 working pair can utilize the heat source with a temperature of above 75°C, and simultaneously realize deep-freezing all the year round. Experimental results and performance prediction show that the adsorption quantity of calcium, theoretical coefficient of performance (COP) and optimized specific cooling power (SCP) of the CaCl2/BaCl2-NH3 chemisorption system are 0.489 kg/kg (salt), 0.24 and 120.7W/kg, when the heating temperature, ambient cooling temperature, pseudo-evaporating temperature and mass ratio of reacting salt and expanded graphite are 85, 30, -20, and 4:1, respectively. © 2011 Higher Education Press and Springer-Verlag Berlin Heidelberg.