Investigation of Ethanol/metal organic frameworks for low temperature adsorption cooling applications Ahmed Rezk, Raya AL-Dadah ⇑ , Saad Mahmoud, Ahmed Elsayed School of Mechanical Engineering, University of Birmingham, Birmingham, United Kingdom highlights  MIL-101Cr MOF can adsorb Ethanol and exhibit a stable performance.  MIL-101Cr/Ethanol adsorption characteristics modeled by Dubinin and LDF models.  MIL-101Cr/Ethanol can be used in low temperature adsorption cooling applications. article info Article history: Received 6 October 2012 Received in revised form 13 June 2013 Accepted 22 June 2013 Available online 17 July 2013 Keywords: Metal Organic Framework (MOF) Ethanol Adsorption Low temperature cooling abstract Adsorption cooling is a promising technology that can effectively utilize waste heat from many industrial processes for refrigeration and air conditioning. Commercially available adsorption systems are based on silica gel/water, zeolites/water and activated carbon/ammonia pairs. These suffer from various limita- tions including: achieving cooling below zero for refrigeration applications and the use of highly poison- ous refrigerant like the ammonia. Metal Organic Framework materials (MOFs) are new micro-porous materials with exceptionally high porosity and large surface area that can be used as adsorbents. Ethanol is a natural non-toxic refrigerant with low environmental impact that can operate at temperatures below zero. This paper experimentally investigates the Ethanol adsorption characteristics of six MOF materials compared to that of silica gel as a conventional adsorbent material that is widely used in commercial adsorption systems. Results revealed that MIL-101Cr have shown superior performance with uptake value of 1.2 kg ref /kg ads . Also, MIL-101Cr proves to be stable through 20 successive cycles at 25 °C. Results from theoretical modeling of a two bed adsorption system with heat and mass recovery have shown that using MIL-101Cr/Ethanol pair can achieve evaporator temperature close to 15 °C and propylene glycol outlet temperature of 7 °C. These results highlight the potential of MOF/Ethanol in low temperature cooling applications, in particular MIL-101Cr MOF. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction Commercially available adsorption systems capable of produc- ing low temperature cooling for refrigeration applications are lim- ited to ammonia based refrigerant that has the disadvantage of being toxic. Therefore, there is a need to use a non-toxic refrigerant in a low temperature adsorption system. Ethanol refrigerant has the advantages of high thermal stability, low freezing temperature, non-toxic, good latent heat of evaporation and compatible with wide range of materials [1]. Metal Organic Frameworks (MOFs) are new micro-porous mate- rials with exceptional high porosity, uniform pore size, well-defined molecular adsorption sites and large surface area (up to 5500 m 2 /g). MOFs have two main components: the organic linkers considered as organic secondary building unit, act as struts that bridge metal cen- ters known as inorganic primary building units and act as joints in the resulting MOF architecture. The two main components are con- nected to each other by coordination bonds, together with other intermolecular interactions, to form a network with defined topol- ogy [2,3]. MOFs have been originally developed and investigated for gaseous fuel storage such as hydrogen and methane [4,5]. The potential of using MOF materials for adsorption cooling applications was reported by Henninger et al. [6] who compared the water adsorption characteristics of eleven adsorbents including one MOF material. The tested copper benzene-1,3,5-tricarboxylate (Cu-BTC) MOF material outperformed the performance of all other materials tested in terms of the water uptake. Rezk et al. [7] inves- tigated the water adsorption performance of seven different MOFs namely; Cu-BTC (copper based and commercially known as Baso- lite C300) [8], Fe-BTC (iron based and commercially known as Bas- olite F300) [8], MIL-53 (chromium based) [9], MIL-53 (iron based) [9], Birm-1 [10], Birm-1-K [10] and Birm-1-Li [10]. Their results showed that the Cu-BTC and Fe-BTC MOF materials produced the 0306-2619/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.apenergy.2013.06.041 ⇑ Corresponding author. Tel.: +44 12141435. E-mail address: r.k.al-dadah@bham.ac.uk (R. AL-Dadah). Applied Energy 112 (2013) 1025–1031 Contents lists available at SciVerse ScienceDirect Applied Energy journal homepage: www.elsevier.com/locate/apenergy