Design And Performance Characteristics Of Solar Water Bath Type Solid Adsorption Refrigeration System

A water-bath solid adsorption refrigeration system driven by solar hot water is designed and built in this paper, which can solve the existed defects of the traditional flate-plate finned tube adsorption refrigeration system: the first is that the inhomogenously heated adsorption bed in the heating desorption process results in the less desorption amount of refrigerant, the second is that the cooling rate of adsorption bed in the cooling adsorption process is slower, the third is that the system cooling performance is greatly influenced by the change of solar radiation. The experimental research on the operation effect and cooling performance of system is conducted. The main work contents of this paper are as follows:(1) For optimizing the performance of solar-powered adsorption refrigeration system, the finned-tube solar adsorption refrigeration system with the fuction of heat storage and heat supply is designed and producted through theoretical calculation, and the construction and commissioning of system is completed.(2) For the finned-tube solar water-bath adsorption refrigeration system, the fin concentric tube adsorbent bed is placed in a thermal insulation water tank, and heated by hot water-bath. the temperature distribution and characteristics of adsorbent bed under the condition of maintaining the desorption temperature at 94℃、85℃、75℃ and heating the water to reach at 94℃ then naturally cooling the hot water without maintaining heating are researched through experiments.(3) Utilizing the solar hot water and the electrical heater assistance heating act as the driving heat source. The adsorbent bed located in the thermal insulation water tank is heated in water bath during the desorption process, thus the refrigerants in the adsorbent bed is desorbed by heating. The effect of desorption temperature and desorption time on the system cooling performance are researched through experiments. The experimental results show that the desorption temperature and desorption time have important influences on performance of the ice-making system. The higher desorption temperature is beneficial to desorption of adsorbate during desorption process. With the increase of heating desorption time, the daily ice-making capacity and direct refrigeration capacity also increase. However, the evaporation heat release of system also drastically increase, thus the gradual increase of energy imported into the system when the operational conditions are maintained, which lead to the low COP and the low heat utilization efficiency of the system. The heating desorption time of 10 h is optimal for the system, and a longer desorption time has no obvious influence on the desorption effect.(4) The cooling performance of solar-powered adsorption refrigeration system with and without mass transfer process control are researched under the different contidions of desorption time. The adsorption refrigeration system with and without mass transfer process control under the condition of the fairly receiving energy, the refrigeration efficiency of system without mass transfer process control is higher than that with mass transfer process control on the whole, and the average cooling efficiency of 20% is higher than that with mass transfer process control. The average daily ice-making capacity of system without mass transfer process control is 1.16 times of mass transfer process control system.(5) The effect of condensation temperature on the cooling performance for the system without mass transfer process control is further researched. When the solar adsorption refrigeration system without mass transfer process control fairly receives the energy inputed by outside, with the decrease of condensing temperature, the cooling performance of system is increasing. The condensing temperature has a great influence on the cooling performance for solar adsorption refrigeration system.The solar solid adsorption refrigeration system with water-bath is proposed in this paper, not only can output stable cooling capacity, but also can provide thermal energy with a certain quality for family. The obtained results provide the basic theoretical and experimental support for the further research and practical application of solid adsorption refrigeration technology, and also provide some experimental basises for the research of solar solid adsorption refrigeration based on multiple cycle.