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High-effectiveness miniature cryogenic recuperator
Gyuwan Hwang,Jeheon Jung,Sangkwon Jeong 대한설비공학회 2009 International Journal Of Air-Conditioning and Refr Vol.17 No.2
The performance of cryogenic refrigerator greatly depends on the effectiveness of heat exchanger, which generates major entropy at low temperature. There are numerous types of heat exchanger available, but it is not easy to apply most of them to cryogenic application because the cryogenic heat exchanger must have high effectiveness value as well as small conduction loss in the environment of considerable temperature difference. In this paper, two kinds of heat exchanger are noticeably introduced for high-effectiveness miniature cryogenic recuperator (recuperative heat exchanger). Also, the flow mal-distribution problem, which is a critical issue of performance deterioration in a high-effectiveness recuperator, is addressed with simplified model, and its alleviation method is discussed.
황규완(Gyuwan Hwang),백승환(Seungwhan Baek),정상권(Sangkwon Jeong) 대한설비공학회 2011 대한설비공학회 학술발표대회논문집 Vol.2011 No.7
The mixed refrigerant JT (Joule-Thomson) cooling system has been investigated in this study. The mixed refrigerant is composed of completely non-flammable refrigerants while the preceding studies have focused on the flammable refrigerants. The experimental apparatus is constructed to examine the actual performance of the developed non-flammable mixed refrigerant JT cooling system. The extensive experiments have been conducted; the cold-end temperature of 178 K (-95℃) is achieved with the mixture composed of N₂, R14, R23, and R218 with 7%, 27%, 18%, and 48% mole fraction, respectively. The result shows the positive prospects of a non-flammable mixed refrigerant JT cooling system. The experimental result is discussed with the limitation of this study and the way of improvement to achieve lower temperature.
백승환(Seungwhan Baek),황규완(Gyuwan Hwang),정상권(Sangkwon Jeong) 대한설비공학회 2008 대한설비공학회 학술발표대회논문집 Vol.2008 No.2
The new concept for liquefaction of natural gas has been designed and simulated in this paper. Conventional liquefaction cycles are usually composed with Joule-Thomson valves at lower temperature refrigerant cycle. The new concept of natural gas liquefaction is discussed. The main difference with conventional liquefaction process is the presence of the turbine at low temperature of MR (mixed refrigerant) cycle. The turbine acts as expander but also as an energy generator. This generated energy is provided to the compressor which consumes energy to pressurize refrigerants. The composition of the mixed refrigerant is investigated in this study. Components of the refrigerant are methane, propane and nitrogen. Composition for new process is traced with Aspen HYSYS software. LNG heat exchangers are analyzed for the new process. Heating and cooling curves in heat exchangers were also analyzed.