Research On The Characteristic And Optimization Of Condenser In Solar Ejector Refrigeration System

The application of air condition and refrigeration provide a comfortable working environment for human being while also consuming a lot of energy.Solar ejector refrigeration system attracts much attention in the advantages of energy-saving,simple structure,long life and high system stability and high attention.However,the efficiency of solar ejector refrigeration system is very low,therefore it is great significance to improve the efficiency of the system.The existing literature on the improvement of the performance of the system include refrigerant,jet refrigeration system structure form and injector optimization research,but the lack of condenser by optimizing the system components in order to improve the study of the overall system performance.In this paper,based on the study of the comprehensive performance of the condenser,the numerical simulation method is used to achieve the purpose of improving the refrigeration efficiency and optimizing the performance of system.In this article,the ratio of the convective heat transfer coefficient of the condenser shell to the 1/3 to the power of pressure drop and the coefficient of performance of COP are selected as the evaluation index of the condenser’s comprehensive performance and the performance of the whole condenser,following conclusions are rechieved:1.Using TRNSYS software and combining with the FORTRAN program of the ejector structure design and performance to establish solar ejector refrigeration system,calculating the variation of the parameter of refrigeration system with solar radiation intensity under a typical meteorological conditions.By the TRNSYS software simulation results,the variation tendency of primary flow with time is increased first and then decreased,which is due to the higher temperature,the inlet pressure of ejector is higher,so the first flow.At the same time,jet coefficient decreases first and then increased with time,because the higher the general temperature,the smaller the ejector coefficient,when constant the evaporation temperature,ejector structure parameters are constant and the condensing temperature is lower than the critical condensation temperature conditions.2.Condensing flow under influence of sum of primary flow and secondary flow.When the system began and end to run,the condensing flow became minimum,15:00 reached a maximum value of about 0.1801kg/s.According to the simulate calculation of the condenser heat transfer and referring to the manual of heat exchanger and the HTRI software to design a tube and shell condenser,and establish the physical condenser model by FLUENT software.3.Combined with the FLUENT and TRNSYS software,the calculation results show that when the baffle spacing is 260 mm,heat exchange tube pitch is 32 mm,and the segmental height of baffle change from 0.2D to 0.4D,the higher the segmental height of baffle,the smaller the convective heat transfer coefficient and pressure drop of condenser.When segmental height is 0.2D,the comprehensive performance of the condenser and coefficient of system’s performance is better than others.4.When segmental height of baffle take 0.2D,pitch of heat exchange tubes take 32 mm and keep constant,and the pitch of baffle change from 180 mm to 260 mm,the more number of baffles(the smaller pitch of baffle),the bigger convective heat transfer coefficient and pressure drop.And when the pitch of baffle is 180 mm,the comprehensive performance of condenser and coefficient of system’s performance is better.5.When segmental height of baffle is 0.2D,pitch of baffle is 180 mm and constant,and the pitch of heat transfer tubes change from 30 mm to 34 mm,pitch of heat transfer tubes exist optimum value.When pitch of tubes take 32 mm or 34 mm,the comprehensive performance of the condenser is best,when the pitch of tubes is 32 mm,the cooling capacity and COP of the solar ejector refrigeration system is best.