Research And Optimization On Performance Of Evaporator In Solar Ejector Refrigeration System

With the development of solar ejector refrigeration(SER) technology, the optimization of components in solar ejector refrigeration system(SERS) has also gotten more and more attention. In this paper, on the basis of SERS evaporator’s working characteristics; evaporator’s working performance and comprehensive performance of SERS corresponding are researched using FLUENT software by numerical simulation method. In the process, the ratio of heat transfer coefficient and pressure drop h/△P and SERS overall performance coefficient COPorll are taken as evaluation index of evaporator integrated performance and SERS overall performance respectively. Main research contents and results of this Paper are following aspects.1. The system’s TRNSYS model is established by which the evaporator’s working characteristics within SERS during system’s running time are simulated and calculated. Results showed that under influence of entrainment ratio and primary flow together, the circulation flow rate of refrigerant through SERS’s evaporator is minimal when the system strats to run, maximum around 14:00.2. Performance of flooded evaporator and dry-expansion shell and tube evaporator during system’s running time is compared based on FLUENT software. Results show that in design conditions, for dry-expansion shell and tube evaporator and flooded evaporator with same heat transfer area, a heat transfer coefficient of about 500 W/(m2·K) and 1200 W/(m2·K) is presented respectively.3. The effect of heat exchange tube spacing and relative distance of inlet and outlet on performance of evaporators during system’s running time is studied based on FLUENT software. Results show that with a relative distance of inlet and outlet of 700 mm, as heat exchange tube spacing descends from 23 mm to 15 mm, evaporator’s comprehensive performance goes up from 0.006 to 0.022; with a heat exchange tube spacing of 15 mm, as relative distance of inlet and outlet raises from 300 mm to 700 mm, evaporator’s integrated performance descends from 0.023 to 0.021.4. The effect of heat exchange tube spacing and relative distance of inlet and outlet on SERS overall performance is researched based on FLUENT software. Results show that with a relative distance of inlet and outlet of 700 mm, as heat exchange tube spacing descends from 23 mm to 15 mm, SERS’s maximal overall performance coefficient increases from 0.1 to 0.22; with a heat exchange tube spacing of 15 mm, as relative distance of inlet and outlet raises from 300 mm to 700 mm, SERS overall performance coefficient increases slightly.5. During system’s running time, effect of refrigerant’s liquid content at inlet on working performance of flooded evaporator and overall performance of SERS corresponding is researched based on FLUENT software. Results show that with a relative distance of inlet and outlet of 700 mm and a heat exchange tube spacing of 15 mm, as refrigerant’s liquid content raises from 30 to 100 percent, evaporator’s comprehensive performance decreases from 0.12 to 0.02, while SERS overall performance increases from 0.14 to 0.22.