Comparison of the adsorption performance of compound adsorbent in a refrigeration cycle with and without mass recovery

Adsorption and desorption were performed on a compound adsorbent composed of CaCl2CaCl2 and activated carbon in cycles both with and without mass recovery and the performances obtained were compared with those of equilibrium adsorption. Experimental results of the cycles without mass recovery carried out on an adsorption refrigeration unit yielded performances that were slightly less than those of equilibrium adsorption. The adsorption performances of the cycle with mass recovery were measured to be much better than those of the cycle without mass recovery. At -15∘C of evaporating temperature, the cycle adsorption capacity was as high as 0.78 kg/kg for the cycle with mass recovery while it was only 0.55 kg/kg for the cycle without mass recovery. The average adsorption/desorption rate of the cycle with mass recovery, which was 0.031 (kg/kg)/min, has been improved by 47.6% compared with that of the cycle without mass recovery. Research on the cycle adsorption capacity at different evaporating temperatures showed that the improvement of cycle adsorption capacity, with mass recovery, was higher under the condition of lower evaporating temperature. At -35∘C evaporating temperature, the mass recovery operation had improved the adsorption capacity by 78% compared with the cycle without mass recovery. In addition, refrigeration performances for the cycles with and without mass recovery at an evaporating temperature of -25∘C were studied. Compared with the results of the cycle without mass recovery, SCP (specific cooling power) and COP (coefficient of refrigeration performance) have been improved by 48.6% and 54.5%, respectively, when mass recovery is performed.