Optimum And Experimental Study On Solar Powered Solid Adsorption Refrigeration System

Some present refrigerants, such as CFC and HCFCs will be forbidden in the near future. So there is a demand of developing some new alternative refrigerating systems and new refrigerants. Among them, sorptive refrigeration systems, adsorptive units specially have the patential to be a kind of alternative units. They can take low-level energy as their motive sources and are friendly to environment. In solar refrigeration systems for ice making, activated carbon-methanol solid adsorption refrigeration system is the most promising technology with low cost, high efficiency, simple manufacturing process and low maintenance requirements etc.. Therefore, this type of refrigeration unit has been regarded as one of the best refrigeration technology in some areas, such as remote area and grazing land where there are no electric power supply, for storing their agricultural products, food and medicine(vaccines) to improve the life of people there.Detailed theoretical and experimental studies on solar powered adsorption refrigeration have been carried out in the thesis. Some related energy equations in the refrigeration cycle are developed and some important related theories are developed and discussed.Selection of working pairs for adsorption systems is an important aspect not only for improving COP of cooling system but also for increasing refrigeration capacity per unit weight of adsorbent. Systematic and detailed quantitative and qualitative principles on the choice of adsorbate-adsorbent system have been developed by the author. A theoretical cycle COP model(A Visual Basic computer program) is presented and developed for studying effects of various parameters of working couple on the performance of refrigeration system, which could save experimental times. Adsorption data were obtained for methanol on two samples of commercial activated carbon, A.C.207E4 and A.C.207E4 obtained from methanol thermal decomposition experimental rig. These data were used to analysis the performance of our prototype and to know the mechanism of long term performance caused decline. In the same time, a simple enhancing method for improving carbon adsorption property was found. Different data processing techniques, by D-R or D-A equation, have different effects on the carbon parameters. The most appropriate form of data processing is discussed to give a criterion from which all researchers in this field could compare different values of COP.In order to study the long term performance reliability of solar powered solid adsorption refrigeration systems, an investigation of thermal decomposition of methanol on various alloys' surfaces under solid adsorption refrigeration condition has been carried out at Monash University. Other relevant detailed researches on the intermittent solar powered solid adsorption refrigeration systems using activated charcoal and methanol as working couple have also been carried out as the first one to study, which includes analyzing the products of thermal decomposition of methanol on pure activated charcoal and various alloys' surface, the rate of thermal decomposition, and the relationship between the performance decline of solar ice maker and the rate of thermal decomposition of methanol and so on. The in-door laboratory simulation showed that the thermal decomposition of methanol did occur in the normal solar powered adsorption refrigeration system. Diethyl-ether, Methoxymehyl methyl ether and other compounds were found in the decomposition products. The rate of the decomposition depends on the presence of various alloys.