Experimental testing of a lab-scale adsorption chiller using a novel selective water sorbent “silica modified by calcium nitrate”

In this paper, a novel composite water sorbent “silica modified by calcium nitrate” (SWS-8L) has been tested for utilization in adsorption chillers driven by low-temperature heat. The isosteric diagram of the working pair under investigation has been calculated from experimental adsorption data measured at equilibrium. The equivalent specific heat of the sorbent as a function of the water loading was experimentally measured by a calorimetric technique. Thermodynamic cooling COP was estimated to be 0.51–0.71, with desorption temperature lower than 90 °C. Real performance was measured by testing a SWS-8L based sorbent bed in a lab-scale adsorption chiller. With this aim, SWS-8L grains were embedded inside a compact aluminium heat exchanger with high thermal efficiency. Experimental cooling COP, mass specific cooling power SCP and volumetric specific cooling power VSCP obtained are 0.18–0.31 (cycle time 10 min), 190–389 W/kg dry sorbent and 104–212 W/dm3, respectively.