Thermodynamic Analysis of a Modified Two-Stage Trans-Critical CO2 Refrigeration Cycle with Multi Inter-Cooling System
محورهای موضوعی : Mechanical EngineeringAhmad Reza Rahmati 1 , Ali Gheibi 2
1 - Department of Mechanical Engineering,
University of Kashan, Iran
2 - Department of Mechanical Engineering,
University of Kashan, Iran
کلید واژه: Ejector-expansion, Two-stage, Refrigeration, Internal heat exchanger, Transcritical,
چکیده مقاله :
Performance of a two-stage multi-inter-cooling trans-critical CO2 refrigeration cycle containing internal heat exchanger, two intercoolers, ejector, and separator, has been analyzed after modification. In the present study, an internal heat exchanger has been included within this cycle for possible improvement in its cooling performance. The impacts of operational parameters such as gas cooler and evaporator temperatures and gas-cooler pressure, on cycle performance have been investigated. Results are validated against those available in the literature. Comparisons of the results show that there is excellent agreement between them. Obtained results showed that modified cycle improved the maximum coefficient of performance (COP max), by 20.58% compared to the internal heat exchanger two-stage TRCC cycle and 23.2% compared to multi-inter-cooling two-stage TRCC cycle with ejector expansion device. Also, the total exergy destruction rate of the improved cycle is between its rates of two original cycles.
[1] Yuhala, H., Wang, J., Denso Corporation, “Private Communicationˮ, Tsinghua in Beijing, China, 2004.
[2] Kornhauser, A. A., “The use of an Ejector as a Refrigerant Expander”, Proceedings of the 1990 USNC/IIR-Purdue Refrigeration Conference, 1990, pp. 10–19.
[3] Domanski, P. A., “Theoretical Evaluation of Vapor Compression Cycle with a Liquid-Line/Suction-Line Heat Exchanger, Economizer, and Ejector”, National Institute of Standards and Technology, March 1995, pp. 134-145.
[4] Wu, J. T., Liu, Z. G., Guo, H., and Fu, Q. S., “Thermodynamic Analysis of a New Kind Vapor-Compression/Ejection Refrigeration Cycle”, Fluid Machinery No. 28, 2000, pp. 47-47.
[5] Disawas, S., Wongwises, S., “Experimental Investigation on the Performance of the Refrigeration Cycle using a Two-phase Ejector as an Expansion Device”, International Journal of Refrigeration, 2004, pp. 587–594.
[6] Deng, J. Q., Jiang, P. X., Lu, T., and Lu, W., “Particular Characteristics of Trans-critical CO2 Refrigeration Cycle with an Ejector”, Applied Thermal Engineering, No. 27, 2007, pp. 381–388.
[7] Yari, M., “Performance Analysis and Optimization of a New Two-stage Ejector Expansion Trans-critical CO2 Refrigeration Cycle”, International Journal of Therm. Sci. No. 48, 2007, pp. 1997-2005.
[8] Eskandari, F., Yavari, M. A., “Performance of a New Two-stage Multi-inter-cooling Trans-critical CO2 Ejector Refrigeration Cycle”, Applied Thermal Engineering, No. 40, 2012, pp. 202–209.
[9] Liao, S. M., Zhao, T. S., and Jakobsen, A., “Correlation of Optimal Heat Rejection Pressures in Trans-critical Carbon Dioxide Cycles”, Applied Thermal Engineering, No. 20, 2012, pp. 831–841.
[10] Goodarzi, M., Gheibi, A., “Performance Analysis of a Modified trans-critical CO2 Refrigeration Cycleˮ, Applied Thermal Engineering, 2015,pp. 1118-1125.
[11] Yari, M., Sirousazar, M., “Cycle Improvements to Ejector-expansion Trans-critical CO2 Two-stage Refrigeration Cycle”, InternationalJournal of Energy Research, No. 32, 2013.
[12] Liao, S. M., Zhao, T. S., and Jakobsen, A., “Correlation of Optimal Heat Rejection Pressures in Trans-critical Carbon Dioxide Cycles”, Applied Thermal Engineering, No. 20, 2000, pp. 831–841.
[13] Cengel, Y. A., Boiles, M. A., “Thermodynamics: An Engineering Approachˮ, Mc Graw-Hill, Inc., 6nd ed., 2007,
[14] Bejan, A. (ed), “Thermal Design and Optimizationˮ, John Wiley and Sons, Inc., New York, NY, 1997.
