Abstract
This paper presents the heat transfer characteristics of the internal heat exchanger (IHX) for CO2 heat pump system. The influence on the IHX length, the mass flow rate, the shape of IHX, the operating condition, and the oil concentration was investigated under a cooling condition. Four kinds of IHX with a coaxial type and a micro-channel type, a mass flow meter, a pump, and a measurement system. With increasing of the IHX length, the capacity, the effectiveness, and the pressure drop increased. For the mass flow rate, the capacity of micro-channel IHX are higher about 2 times than those of coaxial IHX. The pressure drop was larger at cold-side than at hot-side. In the transcritical CO2 cycle, system performance is very sensitive to the IHX design. Design parameters are closely related with the capacity and the pressure drop of CO2 heat pump system. Along the operating condition, the performance of CO2 IHXs is different remarkably. For oil concentration 1, 3, 5%, the capacity decreases and the pressure drop increased, as compared with oil concentration 0%.
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This paper was recommended for publication in revised form by Associate Editor Yong Tae Kang
Prof. Young-Chul Kwon received his B.S. degree in Precision Mechanical Engineering from Pusan National University, Korea, in 1989. He then received his M.S. and Ph.D. degrees from POSTECH, in 1991 and 1996, respectively. Dr. Kwon is currently a Professor at the Division of Mechanical Engineering at Sunmoon University in Chungnam, Korea. He serves as a chief of the Institute of Automation and Energy Technology. Dr. Kwon’s research interests include heat exchanger, CO2 cycle, heat pump, and energy recovery ventilator for HVAC&R.
Mr. Dae-Hoon Kim is currently Doctoral student at the Mechanical Engineering from Hanyang University in Seoul, Korea. His research topics include experimental and numerical of CO2 heatpump system. He has conducted a study on the Analysis of Refrigerating & Air-Conditioning Equipment Industry and Its Forecasting Supervising and Testing for Performance of Refrigerator, Freezer and Air-Conditioner.
Prof. Jae-Heon Lee received his B.S. degree in Mechanical Engineering from Seoul National University, Korea, in 1971. He then received his M.S. and Ph. D. degree from Seoul National University in 1977 and 1980, respectively. Dr. Lee is currently a Professor at the school of Mechanical Engineering at Hanyang University in Seoul, Korea. Dr. Lee is currently a president at the Korea Institute research interests include simulation of thermal fluid and Plant engineering and construction.
Dr. Jun-Young Choi received his B.S. degree in Mechanical Engineering from Yonsei University, Republic of Korea, in 1989. He then received his M.S. and Ph. D. degrees from Yonsei University in 1991 and 1999, respectively. Dr. Choi is currently a chief researcher with the 18 years experience on the energy performance testing of HVAC/R product. He is now assigned to the Energy Technology Center at Basic Industry Division at Korea Testing Laboratory. He has been involved in the development of Design and Manufacturing Technology for Air-Conditioner E.E.R. and Performance Testing Equipment for Cooling and Heating System with Non-CFCs, and natural refrigerants. He has conducted a study on the Analysis of Refrigerating & Air-Conditioning Equipment Industry and Its Forecasting Supervising and Testing for Performance of Refrigerator, Freezer and Air-Conditioner.
Dr. Sang Jae Lee received his Ph.D. degree in Mechanical Engineering from Hanyang University, KOREA, in 2008. Dr. Lee is currently a Researcher at the Korea Institute of Industrial Technology in Cheonan, Korea. Dr. Lee’s research interests CO2 heatpump system, liquid desiccant air conditioning system and Micro heat exchanger.
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Kwon, Y.C., Kim, D.H., Lee, J.H. et al. Experimental study on heat transfer characteristics of internal heat exchangers for CO2 system under cooling condition. J Mech Sci Technol 23, 698–706 (2009). https://doi.org/10.1007/s12206-009-0202-1
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DOI: https://doi.org/10.1007/s12206-009-0202-1