Two bed silica gelewater adsorption chillers: An effectual lumped parameter model Xiaolin Wang, H.T. Chua * School of Mechanical Engineering, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia Received 20 November 2006; received in revised form 20 March 2007; accepted 23 March 2007 Available online 5 April 2007 Abstract This article develops an improved lump-parameter design model to investigate the water-circulation heat recovery scheme as applied to the two-bed silica gelewater adsorption chillers. We demonstrate that performance predictions stemming from this improved lump-parameter formalism compare favorably with experimental results at various conditions, particularly at the in- dustrial rated conditions. We find that the present lump-parameter formalism adequately elucidates the water-circulation heat recovery scheme as does the distributed-parameter formalism. In the studied working condition of a two-bed silica gelewater adsorption chiller, the differences in cooling capacities and coefficients of performance (or COP) by using the two different formalisms are typically less than 10%. This gives rise to a useful and rapid design tool for the industry. Ó 2007 Elsevier Ltd and IIR. All rights reserved. Keywords: Adsorption system; Water; Silica gel; Modelling; Performance Refroidisseurs a ` adsorption au gel de silice a ` deux lits : mode `le des parame `tres regroupe ´s Mots cle ´s : Syste `me a ` adsorption ; Eau ; Gel de silice ; Mode ´lisation ; Performance 1. Introduction Silica gelewater adsorption chiller technology is an ef- fective way of converting waste heat to useful cooling. It has been commercialized in Japan for more than a decade [1,2]. Just as any other chiller technologies, ameliorating the coefficient of performance (COP) has always been a central design objective in the development of adsorption chillers. Various technologies have been diligently pursued. These include the cascading cycle [3], thermal wave [4], combined continuous heat and mass recovery [5] and pas- sive heat recovery scheme [6e8]. Nishiyodo Kuchouki Co. Ltd. [9] and Mayekawa Manufacturing Co. Ltd. [10] are cur- rently practicing different forms of water-circulation heat recovery scheme. In the Nishiyodo scheme, during the switch- ing period, cooling water firstly flows through the hot adsorber which is to be pre-cooled and then into the cold desorber which is to be pre-heated. The energy stored in * Corresponding author. Tel.: þ61 8 64881828; fax: þ61 8 64881024. E-mail addresses: xlwang@mech.uwa.edu.au (X. Wang), htchua@mech.uwa.edu.au (H.T. Chua). 0140-7007/$35.00 Ó 2007 Elsevier Ltd and IIR. All rights reserved. doi:10.1016/j.ijrefrig.2007.03.010 Available online at www.sciencedirect.com International Journal of Refrigeration 30 (2007) 1417e1426 www.elsevier.com/locate/ijrefrig