Study On The Characteristics Of The Solar Ejector Refrigeriation System With Multi-ejector

For our country’s environmental problems and energy shortage is increasing serious,The development and utilization of new energy attarcts attention of our country and the scientific workers. The solar ejector refrigeration, which has the advantages of simple structure, convenient operation and reliable and low power consumption etc.But Set single ejector jet refrigeration system due to its inefficient its application is limited. Therefore, this paper presents a new solar ejector refrigeration system,which sets multi ejector, the system performance is studied and the system operation is optimized.This paper chooses R134 a as the refrigerant of ejector refrigeration system, First of all, based on the theory of gas dynamics, the design program of the ejector and the calculation program of the injection coefficient are programmed by using FORTRAN language. Secondly, the experiment platform of ejector refrigeration system using R134 a as the refrigerant is designed and built, and the working characteristics of ejector are studied. Study on the effects of operating conditions(generating temperature, evaporating temperature, condensing temperature) and mixing chamber diameter on the performance of ejector. The results showed that: at a given injector geometry,the primary gas mass flow increases with the generating temperature, and has nothing to do with the evaporating temperature and condensing temperature; At a given injector geometry and generating temperature, the secondary gas mass flow increases with the evaporating temperature,but as the condensing temperature rises, the secondary gas flow rate first remains unchanged and then decreases sharply, that is to say, at given injector geometry and evaporating temperature, condensing temperature,, there exists an optimum generating temperature to maximize the ejector performance and deviate from this value, the ejector suction performance deterioration; At a given nozzle geometry and evaporating temperature, condensing temperature, with the increase of the diameter of the mixing chamber, the primary gas flow rate is constant, secondary gas flow increases gradually,the critical condensation temperature of the ejector decreased, but the ejector pump performance enhances.In this paper, a layer of 154m2 small villa summer cooling load in Taiyuan was simulated by using TRNBuild, and as a basis for the design of the ejector. A single injector solar ejector refrigeration system and a multi-jet ejector refrigeration system is optimized simulated by using TRNSYS simulation software.The study shows that the performance efficiency of the multi-jet system is better than that of the single ejector for solar ejector refrigeration system, The former is about 12% higher than that of the latter, and the system COP is15.4%~60% higher than that of the latter,The former plate solar collector efficiency is also better than the latter; The solar ejector refrigeration systems’ running which sets up double ejector is superior to the single ejector jet refrigeration system, the system running time is longer than the latter one and a half hours, refrigerating capacity 4.8% ~ 4.8% higher than the latter, the COP is about 10% higher than the latter; The optimal number of ejector in solar ejector refrigeration system is three,The solar ejector refrigeration systems’ running which sets up three ejectors is superior to the jet refrigeration system which sets up double ejectors, The former refrigerating capacity 2.8% higher than the latter, the former COP is about 7% higher than the latter;The solar ejector refrigeration systems’ running which sets up four ejectors is superior to the ejector refrigeration system which sets up three ejectors, but the difference is not big and the system running stability of the former is poor than the latter, Taking into account the initial investment in equipment and system stability, The optimal number of ejector in solar ejector refrigeration system is three;The continuous operation of the solar ejector refrigeration system which sets up three ejectors in typical meteorological weeks(7.9~7.15) is simulated and then compared with the hourly building cooling load, the refrigerating capacity of the solar ejector refrigeration system is much higher than the building cooling load, The excess cooling capacity can be stored by adding the cold storage device in the injection refrigeration system and then supply to the building when the system is off.