Experimental investigation of a solid adsorption chiller based on a heat exchanger coated with hydrophobic zeolite

In this paper, the experimental results of a lab scale adsorption chiller working with hydrophobic Y zeolite-methanol are presented and discussed. The main feature of this chiller is the innovative adsorbent bed consisting of a shell and tube heat exchanger in which the finned tubes are coated with a zeolite layer. In this way, the interesting sorption properties of the Y-type zeolite and the good heat transfer quality of the coated heat exchanger are joined in an advanced, sorption machine, driven by a low temperature heat source. The experimental results on the device show a specific power of 30-60 W/kg of adsorbent (binder included) and a cycle time of 15-20 min depending on the working conditions. These values are sensibly better than those measured with a same zeolite pelletised-bed. This latter bed was realized starting from the same zeolite powder that was extruded using the same amount and-type of binder. The good results obtained, evidently due to the improved heat transfer properties of the advanced bed, sound attractive for those applications in which a quick dynamic cycle is important.