Effects of Adsorber Heat Transfer Area and Residue Gas on the Performance of an Asdorption Chiller

• Main Authors: Po-Yu Hsiao, 蕭柏宇
• Other Authors: 沈君洋
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/4y39pb

碩士 === 國立中興大學 === 機械工程學系所 === 106 === This work deals with a performance improvement of a lab-scale four-bed adsorption chiller. A regular density silica gel and water were used as adsorption pairs. In the experiment, two sets of operating conditions were individually considered and the specifiic cooling power (SCP) and the coefficient of performance (COP) of the adsorption chiller were measured. Through different degassing processes, the influence of residual gas on the system performance was investigated. For increasing the heat transfer area in adsorbens, the original 4 mm-slot finned tubes were replaced by 2 mm-slot finned tubes, and the residual gas in the system was removed by adopting a hot-bed degassing process. In experiment (i), the operating conditions are TG was set at 76.5 oC, Tcond = Tcold = 24 oC, V ̇cw = 1.5 L/min, V ̇hot = V ̇cold = 2 L/min and V ̇cond = 6 L/min. An optimum cycle time of 14 minutes was found. The corresponding maximum SCP value is 246 W/kg-silica gel and the COP value is 0.39; in experiment (ii), the operating conditions are TG =78.1 oC, Tcond = Tcold = 28oC V ̇cw = 1.5 L/min, V ̇hot = V ̇cold = 2.5 L/min and V ̇cond = 6 L/min. An optimum cycle time of 10 minutes was found. The corresponding maximum SCP value is 202 W/kg-silica gel and the COP value is 0.27. Compare theses two experiment could found, when Tcond and Tcold were raised from 24 oC to 28 oC, the SCP is decreased by 18%. When the pressure of the residual gas is reduced by 600 mTorrs, the SCP value can be increased by 23%. The decrease in fin-tube spacing makes the SCP value be increased by 62%. Nevertheless, due to an increase of the weight of the fin-tubes, the COP value is decreased by 34%.