A study was conducted on the adsorption characteristics of the adsorption refrigeration working pairs using alkaline-earth metal chlorides as adsorbents and ammonia as refrigerant. The adsorption isotherms between alkaline-earth metal chlorides and nitrogen were studied. The study shows that the adsorbents of CaCl(2), SrCl(2) provide better adsorption capability associated with ammonia when compared to that of MgCl(2), BaCl(2), CaSO(4) was added into the CaCl(2), SrCl(2) with a mass ratio 20%, respectively, in order to solve the swelling and smashing problems encountered with CaCl(2), SrCl(2) adsorbent particles. The adsorption refrigeration experiments of composite adsorbents were investigated. The results show that the refrigeration capacity ofthe unit adsorbent of CaCl(2)/CaSO(4) is 1.26 times higher than that of CaCl(2), and SrCl(2)/CaSO(4) is 1.6 times higher than that of SrCl(2) at 100 degrees C. The mechanism of NH(3) adsorption and the gelatification of CaSO(4) were also discussed. BET (Brunauer-Emmett-Teller) specific surface area and pore structure of adsorbents were examined. Results show that the BET specific surface area and pore structure of composite adsorbents are retained well. This study indicates that the refrigeration capacity could be enhanced by compositing the adsorbents which indicates that composite adsorbents can perform better in adsorption refrigeration, and can be employed in adsorption refrigeration system using low-grade heat source. (C) 2008 Elsevier Ltd. All rights reserved.