Experimental And Numerical Study On Thermoelectric Cooler Coupled With Vapor Compression Refrigeration

Refrigeration has a wide range of applications in human life and industry.Vapor compression refrigeration(VCR)and thermoelectric cooler(TEC)system have their own advantages and are widely used in daily life.The current refrigeration equipment is based on a single refrigeration system.In order to improve the suitability of refrigeration systems,This paper studies the thermoelectric cooler coupled Vapor compression refrigeratio system.Through the experiment and simulation analysis of the thermoelectric cooler and steam compression refrigeration system,explore the refrigeration characteristics of different coupling structures.A one-dimensional heat transfer model was developed and its local structure was optimized by using the finite element method.The study of TEC coupled VCR system has a wide range of research significance,and can provide reference for the optimization of refrigeration system in the future.Three different Thermoelectric cooler coupled with vapor compression refrigeration systems were constructed and tested experimentally.Firstly,a 18 L insulation compartment was constructed and the influence of the type of TEC,the number of TEC and input power on the temperature was analyzed.Experiment has shown that TEC1-12706 can reach a lower refrigeration temperature compared to TEC1-12705.When the current is 3.17 A,the voltage is 10 V,the minimum temperature of the cold side of the TEC1-12706 is-16.6 ℃.When the current is 3.35 A,the voltage is 12 V,the minimum temperature of the cold side of the TEC1-12705 is-14.7 ℃.After comparing and selecting TEC,the refrigeration system equipped with TEC1-12706 was built.The test results show that the TEC has a significant advantage.At the ambient temperature of 21.5°C,10 W,30W,50 W input power,the temperature in the insulation compartment was cooled to 13.3 ℃,10.4 ℃,9.7 ℃.The average temperature of the finned heat sink at hot side is 24.1℃,26.4℃,28.1℃.The average temperature of the finned heat sink at cold side is 9.7℃,5.5℃,6.7℃.The precise control of the temperature can be achieved by adjusting the input power,and the temperature fluctuation of the insulation compartment is ± 0.2℃.However,the COP of the TEC decreases as the input power increases.When the input power is 10 W,its COP can reach0.53.When its input power is greater than 50 W,its COP is less than 0.1.Subsequently,the VCR was tested.It can be seen that there is a periodic start-stop with the vapor compressed refrigeration system with fixed-speed compressor.The minimum temperature in the 30 L insulation compartment was-24.6 ℃,and the COP was 2.1.configuration I had the same results as the single refrigeration test.In order to further explore the interaction between the two refrigeration systems with different structures,the installation position of the TEC is changed,so that the two systems have a coupling refrigeration relationship.In the configuration Ⅱ,the thermoelectric device is placed in the wall between the TEC compartment and the VCR compartment.In the configurationⅢ,install the cold side of the TEC on the insulation layer.Different experimental structures were constructed.According to the experimental results,the cooling capacity of TEC in configuration Ⅱ was significantly increased compared with configuration Ⅰ.The optimal power range is 0-8W.When the input power of the TEC is 2W,the minimum temperature of the TEC compartment can reach-1.5 ℃,and when the TEC input power is 8W,the minimum temperature can reach-5 ℃.Configuration III can realize the superposition of cooling capacity of TEC and VCR.Compared with TEC or VCR,the time to reach the minimum temperature is shorter,but the energy consumption increases correspondingly.Finally,the application occasions and advantages of different refrigeration systems are summarized in detail.Subsequently,a one-dimensional heat transfer model was established to simulate the TEC system and the VCR system.The results show that the model can predict the heat transfer process of the system,the maximum error is 1.58 ℃.The three configuration structures were discretized based on the computational model,and the energy consumption of the coupled refrigeration system with different configuration structures was analyzed.The simulation results show that configuration Ⅱ has significant advantages over configuration Ⅰ,which can significantly improve the energy utilization rate.In the same insulation compartment(TEC compartment 18 L,VCR compartment 30 L),to achieve the same refrigeration temperature(TEC compartment0 ℃,VCR compartment-20 ℃),configuration Ⅰ needs to increase the number of TEC,so configuration Ⅱ reduces the power consumption of nearly 68% with the same refrigeration temperature.The COP of configuration Ⅲ decreased with increasing input power of TEC.Reducing the thermal resistance of the finned heat sink,which can further improve the performance of the coupling refrigeration system.Using the Fluent thermal simulation software to optimize the cold side finned heat sink of the TEC.The simulation results show that under the same wind speed,the structure is better when the fan is installed at the top.The influences of finned pitch,finned height and fin thickness on inlet and outlet pressure drop,finned average temperature and thermal resistance are further verified and determined that the fin height is 49 mm,the finned pitch is 6mm,and the finned thickness is 0.5mm.The thermal resistance is reduced by 32.2%compared with the initial thermal resistance.