Dynamic study of methanol adsorption on activated carbon ACM-35.4 for enhancing the specific cooling power of adsorptive chillers

Lower specific cooling power (SCP) as compared to absorption and compression chillers slows down a broader application of adsorption cooling (AC) technology. In this paper, we endeavor to find out the factors dominating ad/desorption dynamics in adsorptive chillers and to make practical recommendations on optimizing the SCP. The working pair studied is "activated carbon ACM-35.4 - methanol". This carbon is the modern analog of a well-known carbon AC-35 that has been widely tested for AC units. We have experimentally examined the dynamics under a simple, but realistic configuration of a thin adsorbent bed composed of loose grains located on a flat metal plate. The effects of the adsorbent grain size (0.8-4.0 mm), bed thickness (0.8-5.6 mm), and ad/desorption temperatures are explored under conditions of isobaric stages of AC cycle. The adsorption rate appears to be mainly controlled by the heat transfer between the adsorbent bed and the heat transfer fluid. The ratio (S/m(ad)) of the heat transfer area S to the adsorbent mass m(ad) can be used to assess the degree of dynamic perfection of real adsorber - heat exchanger units. On the base of the main findings obtained the practical recommendations on enhancing the SCP of AC units are made. (C) 2013 Elsevier Ltd. All rights reserved.