Selection and performance of adsorbents in an adsorption refrigeration cycle regenerated with water directly

An adsorption refrigeration cycle regenerated with water directly (ARRD), which has the advantage of excellent heat transfer performance in the adsorbent bed with half-cycling time 3–5 min, and operates close to atmospheric pressure (0.1–0.5 MPa) with n-butane as a refrigerant, is developed. The purpose of this study is to find out advanced adsorbent/n-butane pairs for the ARRD system. Adsorption equilibrium performances of n-butane on the adsorbents were measured by positive pressure gravimetric method, and the adsorption equilibrium data were fitted by D-A equation. Desorption properties were determined through thermal analysis. The coefficient of performance and specific cooling power (SCP) were calculated. The results show that adsorption capacities of n-butane with activated carbon are all above 0.31 kg/kg and the highest can reach 0.43 kg/kg. Adsorption data are fitted well by D-A equation, with the correlative coefficients R above 0.93. Desorption temperatures of n-butane from carbons are between 110 and 130 °C, prospective for using low grade heat source. The quasi-equilibrium of n-butane on carbons can be achieved within 150–250 s, which benefits SCP of the ARRD system. The SCP of n-butane/AC-5 pair estimated in the ARRD systems is from 180 to 200 W/kg.