Performance Analysis Of Automotive Air Conditioning System Using Micro-channel Condenser With Liquid-vapor Separation

This paper product an air cooled liquid-vapor separation micro-channel condenser (LSMC), and the theoretical analysis and experimental research and application was conducted. This paper uses Visual Basic programming language, select the appropriate micro-channel heat exchanger model and the pressure drop model of micro-channel condenser, and designed the tube dispensing structure, to give the LSMCs thermal performance calculation program. Through the experimental method verify the effectiveness and correctness of the program. After the compared experimental data with the theoretical value, proved the method by selecting the programming model to calculate the LSMCs thermal performance is feasible. Under the study conditions, the calculated value and experimental data are compared, the study found that the deviations are basically falls within 20% with Shigeru Koyama heat transfer model and Zhang M pressure drop model.In this paper, a condenser has been optimized was produced, and experimental study by automotive air conditioning systems, the performance of the automotive air conditioning systems used the LSMCs was analysis. In order to comparative study of the system performance differences between the LSMCs and the PFMCs in automotive air conditioning systems, the structural parameters are the same with the LSMC has been manufacture, call PFMC.Experimental results show that at the standard conditions (outdoor dry-bulb temperature is 35℃, indoor dry-bulb and wet-bulb temperature of 27℃ and 19℃, compressor speed is 1800r/min, the condenser inlet air face velocity is 4.5m/s) as R134a refrigerant automotive air conditioning systems, the LSMC system and the PFMC system refrigerant charge, obtain the maximum COP at amount of 1000g and 1050g, respectively, the amount of this charge as the best match the system refrigerant charge.Under the conditions, as the condenser air face velocity increasing, cooling capacity of the LSMC system are increased steeper, and the COP is higher while the compressor speed is higher.Under the standard conditions, the LSMC system refrigerant charge less than the PFMC system, condensation temperature of the LSMC more close to constant, condensing temperature change is smaller, with higher average condensing temperature, and help to improve the condensation heat transfer. The LSMC can reduce the pressure drop of the refrigerant side, which is lower than the PFMC mainly because the liquid-vapor separation effect. Compared with the PFMC, the mass flux of the LSMC is higher than from 3.1% to 10.8%, the LSMC pressure drop is lower than from 7.1% -40.9%. In the experimental condition, the cooling capacity of the LSMC system is higher than the PFMC system from 1.5% to 6.7%, the power consumption of the two systems are similar, the COP of the LSMC is higher than the PFMC from 2.5%to 8.9%.Comparison results of two systems under the idle condition and city condition in IMACA operation condition, the cooling capacity of the LSMC is higher 4.5% and 4.2% than that of the PFMC, respectively. The compressor power consumption of the LSMC is lower 2.4% and 2.2% than that of the PFMC, respectively. And the COP of the LSMC is higher 7.1% and 6.6% than that of the PFMC, respectively. The exergy efficiency of the LSMC was found greater (3.9% to 10.8%) than the PFMC under the running conditions.