Effect of Metal Additives in the Bed on the Performance Parameters of an Adsorption Chiller with Desalination Function

Abstract

Adsorption chillers with desalination functionality, being devices characterised by very low electricity consumption, provide an alternative to conventional sources of cooling and water. The option of desalinating water means that the use of a single device enables obtaining two useful products. Adsorption chillers are not widely used at present. due to their low performance characteristics; these are, however, constantly being improved. This paper presents a verification of the possibility of increasing the cooling coefficient of performance (COP) and specific cooling power (SCP) of a laboratory adsorption chiller by optimising the length of cycle times and using a copper additive to silica gel with a mass fraction of 15% to increase heat transport in the bed. The choice of copper among other considered additives was determined by the conclusions from the research on the sorption kinetics of various mixtures, price and availability, and a high thermal conductivity. The device was operated in a two-bed mode aimed at producing cooling. The adsorbate was distilled water. The results were compared with those obtained under similar conditions when the beds were only filled with silica gel. As a result of the testing, it was found that the use of the copper additive with the sorbent increased both the COP and SCP. The tests were performed for different cycle times, of 100, 200, 300 and 600 s. With increasing cycle time COP also increased. In contrast, the specific cooling power increased only up to a certain point, whereafter its value decreased.