Hybrid adsorption cooling systems–An overview Ahmed A. Askalany a,b , Bidyut B. Saha a,e,n , Keishi Kariya a , Ibrahim M. Ismail c , Mahmoud Salem b , Ahmed H.H. Ali c,d , Mahmoud G. Morsy c a Mechanical Engineering Department, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka-shi, Fukuoak 819-0395, Japan b Mechanical Department, Faculty of Industrial Education, Sohag University, Sohag, Egypt c Mechanical Engineering, Faculty of Engineering, Assiut University, Assiut, Egypt d Department of Energy Resources and Environmental Engineering, Egypt–Japan University of Science and Technology (E-JUST), Egypt e International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan article info Article history: Received 20 January 2012 Received in revised form 29 May 2012 Accepted 4 June 2012 Available online 4 August 2012 Keywords: Adsorption Cooling Hybrid abstract With sharp rising global energy demand posing a rapid development in sustainable cooling systems is required. Hybrid adsorption cooling cycle is considered as one of the sustainable cooling systems. The present study introduces a survey of hybrid adsorption cooling systems in order to stand on its fact and clarify the future trend. The survey sectioned the hybrid adsorption systems into three sections; (i) assisted technology, (ii) application, and (iii) heat source type. The hybrid system which uses vapor compression with adsorption employing activated carbon/CO 2 pair was found to have the highest value of the coefficient of performance (COP). On the contrary, vapor compression-hybrid cooling system using activated carbon/R134a as the adsorbent/refrigerant pair has the lowest COP value and substantial research development and demonstration (RD&D) is required to meet the global challenge of energy conservation. & 2012 Elsevier Ltd. All rights reserved. Contents 1. Introduction ..................................................................................................... 5787 2. Adsorption hybrid systems ......................................................................................... 5788 2.1. Assistant cooling technologies ................................................................................. 5788 2.2. Applications ............................................................................................... 5794 2.3. Heat source ............................................................................................... 5797 3. Summary ....................................................................................................... 5798 4. Conclusions ..................................................................................................... 5798 References ...................................................................................................... 5800 1. Introduction The earliest record of the phenomenon of adsorption refrig- eration is the ammonia adsorption on AgCl, which was discovered by Faraday in 1848 [1,2]. In the 1920s, Hulse [3] suggested a refrigerator which utilized silica gel/SO 2 as a working pair and reached the evaporation temperature of about  12 1C, to store food on trains. Since 1930, the technology of vapor mechanical compression refrigeration has developed quickly, and adsorption refrigeration could no longer compete with those systems. From the oil crisis of the 1970s, attention turned again to adsorption systems for their energy saving potential. There are two types of adsorption refrigeration working pairs: (1) physical adsorption working pairs, such as zeolite/water, activated carbon/methanol, activated carbon/ammonia and silica gel/water; (2) chemical adsorption working pairs, which are mainly metal hydride/hydro- gen and metal chloride (e.g. CaCl 2 , LiCl, etc.)/ammonia. The force between metal chlorides and ammonia is complexation force where the reaction between calcium chloride can be written as CaCl 2 .n 1 NH 3 þ n 2 DHr2CaCl 2 .(n 1 –n 2 ) NH 3 þ n 2 NH 3 Where DH r is the reaction enthalpy (J/mol), the numbers of n 1 and n 2 could be 2, 4 and 8. There are composite adsorbents (e.g. expanded porous gra- phite and CaCl 2 , thus the thermal conductivity could be greatly enhanced) and the compound adsorbents (e.g. activated carbon Contents lists available at SciVerse ScienceDirect journal homepage: www.elsevier.com/locate/rser Renewable and Sustainable Energy Reviews 1364-0321/$ - see front matter & 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.rser.2012.06.001 n Corresponding Author. Tel.: þ81 92 802 3101, fax: þ81 92 802 3125. E-mail addresses: Ahmed_askalany3@yahoo.com (A.A. Askalany), saha@mech.kyushu-u.ac.jp (B.B. Saha). Renewable and Sustainable Energy Reviews 16 (2012) 5787–5801