Experimental And Theoretical Studies On A Bubble Pump Used For The Mixed Refrigerant Diffusion-Absorption Refrigeration System

With the improvement of people’s living standards, the energy consumption in China is exponentially increasing and the problem of energy use and saving is becoming very significant. In the field of refrigeration technology, the diffusion absorption refrigeration system which utilizes low-grade heat to produce cooling capacity has many advantages and attracts more attentions in recent years. The mixed refrigerant diffusion absorption refrigeration cycle owns not only all of the advantages of the traditional one, but also the ability to produce cooling capacity at an even lower temperature. The bubble pump is the key component of mixed refrigerant diffusion absorption refrigeration system. The performance of the bubble pump has remarkable effects on the continuous and stable operation of the cycle, and the efficiency of the system as well. In this thesis, the main research contents in experimental and theoretical studies are shown below:1The present research progress of the bubble pump in the diffusion absorption refrigeration systems at home and abroad has been reviewed. These work defined the significance and future research direction of the thesis.2. We designed and improved the experimental device for bubble pump performance. We accumulated abundant experimental data through numerous experimental measurements. We investigated the effects of parameters such as the liquid storage tank level, pipe diameter, flow pattern, heat flux, concentration of the mixed refrigerant and system pressure on the performance and efficiency of the bubble pump. We summarized the designing principles of the bubble pump used in the mixed refrigerant diffusion absorption refrigeration system.3. The theoretical model of the bubble pump was set up according to the Mass, Energy and Momentum Conservation equations, the Boiling heat transfer theory and Two-phase flow theory. We proposed a modification method considering the resistance loss in the bubble pump, based on which the accuracy of the model was improved.4We simulated the performance of the bubble pump with the improved mathematical model. We fit the model parameters with the experimental data and compared the theoretical simulation results with the experimental data to check the credibility of the model. As a result, the methods we used have considerable accuracy and credibility, which shows the methods are advanced both at home and abroad.