| With the accelerated economic development and resource consumption, the demand ofenergy sources is rapidly increased. The development and utilization of solar and renewable energyhave been paid more attention. The solar ejector refrigeration system can make full use of solarenergy resources for cooling, but it has certain dependence on the weather, and the efficiency of thesystem is restricted by solar radiation condition. Therefore, energy storage technology can be usedfor storing the solar energy when the weather condition is better. The solar ejector-compressioncombined refrigeration system has been studied in this paper.In order to study the new system, the operating principle of the system is analyzed on thebasis of experimental research in the early stage. The steady-state simulation model of componentsand the system has been established, and the simulation calculation program is compiled by thesoftware EES. Though debugging and calculation for the model program, the simulation resultsand experimental data are compared and analyzed, the correctness of the system model has beenverified in this article. In addition, the influence of the overall performance of system has beenanalyzed under different generator temperatures, middle temperatures and evaporator temperatures,and the optimal operation temperature range of system is achieved in this article. Meanwhile, theheat transfer performances of intercooler have been optimized and analyzed and it providestheoretical basis for optimization design of intercooler in the paper.The main research works are asfollows:(1) Based on the principle and thermodynamic analysis of the solar ejector-compressioncombined refrigeration system, the mathematical model of the various components have beenestablished, and the simulation calculation program is compiled by the software EES, mainlyincluding: intercooler, compressor, evaporator, throttle and working medium pump, etc.(2) Based on previous simulation study of the ejection system, the solar ejector refrigerationsystem and electrical system are connected though intercooler. The steady-state simulation model of the combined system is established on the basis of the mathematical model of the variouscomponents. Though debugging and calculation for the model program, the reliability andcorrectness of the components and system model has been verified in this paper. When thegenerator temperature is80℃, the condenser temperature is35℃and the evaporator temperaturerespectively is-5℃, the system EER ranges from2.7to3.6and increases30%.(3) The simulation program is calculated and analyzed under the certain conditions in thepaper. When the evaporator temperature respectively is-5℃,-10℃,-15℃, the middletemperature is10℃, the condenser temperature is35℃, and the generator temperature risesgradually from72℃to85℃, the EER and COP will first increases and then decreases, and thetotal power consumption shows the opposite trends. When other factors are constant, the middletemperature increased from0℃to20℃, theEER of system first increases and then decreases.When the middle temperature is10℃, the condenser temperature is35℃, the evaporatortemperature respectively is-5℃,-10℃,-15℃, and the generator temperature fluctuates between72℃and85℃, the COP ranges from0.3to0.38, and the best generator temperature rage is from78℃to80℃, in the rage, the total power consumption is the minimum, and the largest value ofEER reach to3.13. When the condenser temperature is35℃,the evaporator temperature are at-5℃,-10℃,-15℃, the best ranges of middle temperature are from7℃to10℃, the systemEERcan reach to the highest value within the scope, and the maximum value respectively is3.39,2.86,2.61, and refrigeration capacity can reach2245W.(4) In the paper, the heat transfer performances of intercooler have been researched, whichusing R134a and R236fa as refrigerant, and the sensitivity of structural parameters are analyzed,such as: different length, inner and outside pipe diameter, tooth depth, spiral angle, apex angle, etc.To comprehensively consider the evaluation index of the heat exchanger, the reasonable ranges ofstructure parameters are existed. The heat transfer of intercooler can be achieve optimal effect asthe length of the pipe is from7m to9m, inner tube diameter is between9mm and11mm, outsidetube diameter is between30mm and36mm. Meanwhile, the heat transfer performance isinfluenced by the changes of tooth depth, spiral angle and tooth apex angle of slight ribbed tube. Iftooth depth and spiral angle increase, or tooth apex angle decreases, the heat transfer capacity couldbe improved, but the influence is not obvious, generally within15%. The heat transfer performancecan be achieved optimum as tooth depth is about0.2mm, the spiral angle is30°and tooth apexangle is27°. The results show that: the influence of the overall system performance have been analyzedunder different temperatures, the optimal ranges of the middle temperature and generatortemperature have been received when the system operates. It has promotes effects for improvingthe operation efficiency of the system. Meanwhile, the heat transfer performance of intercooler hasbeen optimized analysis as R134a and R236fa are used as refrigerants, and the reasonable rangesof structural parameters are confirmed. It provides reference and theoretical basis for optimizationdesign of intercooler, and lays a good foundation for realizing industrialization development. |
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