Performance Investigation Of An EEV-based Ejector For Refrigerator

As one of the most common household appliances in daily life,a refrigerator works ceaselessly throughout the year,accounting for a large proportion of power consumption among all appliances.Thus,an energy saving refrigerator is of great significance to national energy conservation and emission reduction strategies and sustainable development.This article proposes an electronic expansion valve(EEV)based ejector for the varying load conditions.The new ejector consists of an electronic expansion valve and the main body of the ejector.By changing the opening degree of the electronic expansion valve,the primary and secondary mass flow of the ejector is controlled,and consequently,it will adapt itself to the variable cooling load of refrigerator.The ejector is designed to ensure a high entrainment ratio under different back pressure conditions.By increasing the compressor inlet pressure to reduce the compressor work,the energy saving of the refrigerator can be achieved.The main works are as follows:(1)The effect of ejector geometry on ejector performance was studied.The key geometry of the EEV-based ejector was optimized to obtain the optimal area ratio and constant area mixing section length.(2)The effect of secondary flow inlet position on ejector performance was also studied.With the changing position of the secondary flow inlet,it shows that different ejector secondary flow inlet positions have a certain influence on the ejector performance and the difference between the maximum entrainment ratio and the minimum entrainment ratio is 7.2%.Therefore,the ejector secondary flow inlet position should be as close to the EEV part as possible to increase the entrainment ratio.(3)The influence of blockage area ratio of the needle valve on ejector performance was investigated.Different blockage area ratios of needle valve were adapted to the different cooling loads of refrigerator.The results show that ejector has a high entrainment ratio when blockage area ratio is 30%to 50%.(4)The effect of back pressure on ejector performance was investigated.The relationship between pressure recovery ratio and ejector entrainment ratio was studied by changing the back pressure.And it shows that the EEV-based ejector can keep higher entrainment ratio at relatively high back pressure.(5)The platform of ejector-compression hybrid refrigeration system was set up to verify the simulation results.The EEV-based ejector is introduced into the ejector-compression hybrid refrigeration cycle and relevant experimental research was conducted on the platform.From the experimental result,it can be concluded that the ejector-compression hybrid refrigeration cycle with an EEV-based ejector has a certain system performance improvement over the conventional compression refrigeration cycle.Moreover,the influence of the condensing temperature was also studied.The novelty about this paper is that an electronic expansion valve is introduced in the ejector for the first time.The area ratio of the EEV-based ejector can be variable and controllable.Therefore,the variable cooling load situation can be accommodated in the refrigerator system.Moreover,the ejector is highly efficient under various conditions.The paper also takes the pressure recovery ratio into account,and the ejector designed can work well under different back pressure conditions.By reducing the compressor work,it will certainly achieve the effect of energy saving.The proposed ejector can realize the preferable miniaturization of the refrigeration system and presents an innovative idea for the refrigerator production in the future.