Experimental And Theoretical Study On Performance Of An Adsorption Chiller Filled With Silica Gel Impregnated With Lithium Chloride

The quantity of global energy use has been in a constant increase for a long time, with thetrend not showing any indication of decline any soon. Need for cooling is among the many reasonsfor the ever increasing demand for energy. It is currently estimated that refrigeration and airconditioning systems consumes about30%of the total worldwide energy consumption. Thisresearch, therefore, is focused on one of the sustainable ways to decrease energy demand forcooling by employing energy saving and environmentally adsorption cooling system. In this study,theoretical and experimental analysis of an adsorption refrigeration system employing a compositeadsorbent of silica gel impregnated with lithium chloride is has been analyzed, with the main focuson effects of different cycle enhancements, working pairs, operating and design conditions on theperformance.The chiller’s experimental test results showed an average Specific Cooling Power (SCP) andCoefficient of Performance (COP) of286Watts/kg and0.48respectively. These values wereobtained with the system average hot water inlet temperature, cooling water inlet temperature, andchilled water inlet temperature of83oC,26oC and15oC, respectively. In addition, thecorresponding mass flow rates were0.22kg/s,0.39kg/s and0.09kg/s, respectively. Despite the factthat the average specific cooling power and Coefficient of Performance (COP), were rathersatisfactory, analysis of experimental results conducted with different cycle times, inlet hot watertemperatures, and hot water flow rates showed that a much better performance could be achieved.Experimental study results indicated the following;(1) the coefficient of performance increasedwhile the specific cooling power decreased with increased cycle time,(2) both the coefficient ofperformance and the specific cooling power increased with increase in heat and mass recovery timeto an optimal time then started to decrease as heat and mass recovery time increased beyond theoptimal time,(3) both the cooling power and COP generally increased with increase in inlet hot water temperature at a relatively higher value from60oC to about90oC beyond which theincremental value started diminishing, and,(4) increase in mass flow rates produced higher coolingpower with decreased COP while decrease in mass flow rates of hot water produced lower coolingpower with increased COP. This study recommends an adsorption/desorption time, heat and massrecovery time, inlet hot water temperature, and hot water mass flow rate of780seconds,60seconds,83oC, and0.22kg/s for the studied refrigeration system as appropriate to give the best performancefor refrigeration.