Study On The Characteristics Of Solar Adsorption Refrigeration System Under Different Mass Transfer Modes

In recent years,environmental pollution caused by fossil energy,especially air pollution has become increasingly serious.One solution is that replacing fossil energy with renewable energy,which can reduce environmental pollution.Solar energy which is rich in resources as a renewable energy can be infinitely renewable.It is of great significance to develop and utilize the solar energy to protect the humans' natural environment.Specifically,a new energy-saving,environmental-friendly and sustainable refrigerating system has been introduced,combining solar energy and adsorption refrigeration together.To date,domestic and foreign scholars have conducted a lot of research and the majority focus on the heat transferring through adsorption bed.However,research on mass transfer at heating desorption phase as well as desorption rate promotion still needs to be developed.The thesis is based on desorption characteristics and the operation mode of the strengthened mass transfer.(1)The relationship between the adsorption pressure and the adsorption rate was discussed through theoretical analysis on the process of refrigerating,heat transfer and mass transfer of solar adsorption system.The system method was obtained to improve the performance of mass transfer.A dual channel structure solar adsorption refrigeration experimental platform with strengthen mass transfer system was also established.The system was added a secondary decompression mass transfer device and a double condenser.It was also set with several strengthen mass transfer modes,namely single pump single condenser,single pump double condenser and dual pump double condenser.Therefore,the best solution could be found though contrastive analysis on the mass transfer characteristics when the system was under different modes and different working conditions.(2)In order to obtain an appropriate strengthened mass transfer mode for the adsorption refrigeration system,indoor simulated light source was used as the source of thermal energy to test performance of the system when it was under different strengthened mass transfer modes.Through analyzing the transfer-mass characteristics,it was found out that at the same desorption temperature,the system performed better when it was with single pump double condenser because the internal pressure in the first condenser was reduced efficiently,which is more conducive to enhance the refrigerant circulation performance in the mass-transfer pipe.(3)In order to understand the stability of the strengthened mass transfer,compared to natural mass transfer,experiment was carried out in the outdoor environment under the cloudless and cloudy working conditions to observe the impact from solar radiation intensity on the refrigerant desorption capacity.Through contrastive analysis on characteristics of single pump double condenser under strengthened mass transfer mode and natural mass transfer mode respectively when it was under two different working conditions,it was found that in the strengthened mass transfer process,the refrigerant desorption capacity was increased by 19.1% and20.5% respectively,compared with the natural mass transfer process.It demonstrated that refrigerant performance of the single pump double condenser with strengthened mass transfer performed better than when it was with natural mass transfer,which was more suited to solar adsorption refrigeration needs.