Effects of contact resistance and metal additives in finned-tube adsorbent beds on the performance of silica gel/water adsorption chiller

Abstract

Recently interest in adsorption cooling systems has increased due to their capability to utilise low grade heat sources and environmentally friendly refrigerants. Currently, most of the commercially available adsorption cooling systems utilise granular packed adsorbent beds. Enhancing the heat transfer process inside the adsorbent bed will improve the overall efficiency of the adsorption system. Using recently developed empirical lumped analytical simulation model for a 450 kW two-bed silica gel/water adsorption chiller, this paper theoretically investigates the effects of various adsorbent bed heat transfer enhancement techniques on the adsorption system cooling capacity. Firstly, coating the first adsorbent layer to the metal part and packing the rest of adsorbent granules to eliminate the thermal contact resistance between heat exchanger metal and granules while keeping the same level of permeability. Secondly, adding metal particles to the adsorbent in order to enhance the granules thermal conductivity. The effective thermal conductivity of adsorbent/metal mixtures were determined and validated by comparing it with published experimental data. Also, the combined effect of using both techniques simultaneously was investigated. All these investigations were carried out at various adsorption bed fin spacing. Results of the combined techniques showed that the enhancement in the cooling capacity and system coefficient of performance (COP) increased with increasing the fin spacing ratio to reach maximum of 25% and 10% respectively at fin spacing ratio of 2.

Publication DOI: https://doi.org/10.1016/j.applthermaleng.2012.04.008
Divisions: College of Engineering & Physical Sciences > Mechanical Engineering & Design
College of Engineering & Physical Sciences
Additional Information: © 2012 Elsevier Ltd. Open access under CC BY license.
Uncontrolled Keywords: Adsorption chiller,Contact resistance,Metal additives,Silica gel/water,Energy Engineering and Power Technology,Industrial and Manufacturing Engineering
Full Text Link:
Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
https://www.sci ... 2396?via%3Dihub (Publisher URL)
PURE Output Type: Article
Published Date: 2013-05-02
Authors: Rezk, A. (ORCID Profile 0000-0002-1329-4146)
Al-Dadah, R. K.
Mahmoud, S.
Elsayed, A.

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