Browse Technical Reports - Air Conditioning and Refrigeration Center by Title

  • Fei, P.; Hrnjak, P.S. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2004-01)
    This research is focused on the experimental analysis and numerical simulation of adiabatic developing two-phase refrigerant flow in manifolds including the inlet tube after the expansion device. The two-phase flow ...

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  • Malik, T.; Bullard, C.W. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2004-06)
    HEVs idle their engine during the stops to meet the cooling and heating needs. But, idling decreases fuel economy and increases engine wear and emissions. The report explores alternative strategies for air conditioning ...

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  • Ge, H.; Jacobi, A.M.; Dutton, J.C. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2002-10)
    Offset-strip fins are used in many compact heat exchanger applications because of excellent thermalhydraulic performance. Enhancing the air-side heat transfer performance for offset-strip fins can lead to smaller, more ...

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  • Tang, A.D.; Jacobi, A.M. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2001-07)
    The effect of condensate retention on the air-side heat transfer and pressure drop performance of automotive evaporator coils was studied. Experiments under wet and dry conditions were conducted using offset strip and ...

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  • Meyer, J.J.; Dunn, W.E. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 1996-12)
    This study examines the mass flow rate of refrigerants in adiabatic capillary tubes, with an emphasis on the nature of the metastable region for both single component refrigerants and mixtures. The metastable region of ...

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  • Xia, Y.; Hrnjak, P.S.; Jacobi, A.M. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2006-12)
    The thermal-hydraulic behavior of folded-louvered-fin, microchannel heat exchangers is explored under conditions of air-side frosting, defrosting, and refrosting. The temperature distribution within a two-dimensional composite ...

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  • Poort, M.J.; Bullard, C.W. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2005-05)
    Rapid cycling of the compressor can be used to modulate capacity as an alternative to variable speed a/c and refrigeration systems. This paper outlines design recommendations to optimize rapid cycling performance based on ...

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  • Rubas, P.J.; Bullard, C.W. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 1993-07)
    Thermal mass effects, refrigerant dynamics, and interchanger transients are three factors affecting the transient and cycling performance of all refrigeration and air conditioning equipment. The effects of refrigerant dynamics, ...

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  • Shedd, T.A. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 1997-12)
    The need to measure the thickness of thin liquid films is evident from the number of methods that have been developed to do so. Many of these methods have significant drawbacks, such as intrusive probes or the dependence on ...

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  • Sweeney, K.A.; Chato, J.C. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 1996-04)
    Condensation of a near-azeotropic mixture of 45% R-32 and 55% R-125 has been studied in a microfinned tube. The local behavior of heat transfer coefficient and the pressure drop was found to be a function of both quality ...

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  • Jain, S.; Bullard, C.W. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2004-05)
    Air conditioning and refrigeration systems are designed to meet the load at some particular design conditions. At off-design conditions, the compressor is either cycled or a variable speed drive enables the compressor ...

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  • Park, C.Y.; Hrnjak, P.S. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2007-01)
    Carbon dioxide (CO2) has been seriously considered as an alternate refrigerant for HCFC and HFC fluids, due to the increasing interest of environmentally safe refrigerants in air-conditioning and refrigeration systems. ...

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  • Hurlburt, E.T.; Newell, T.A. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 1997-02)
    Common refrigeration and air conditioning cycles are dependent on two-phase flow for efficient heat transfer with minimal pressure drop. Design of heat exchangers for these systems is aided by an understanding of the ...

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  • Shedd, T.A. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2001-03)
    Horizontal annular two-phase flow is a very important condition in many common applications, including power generation, air-conditioning, and refrigeration. The purpose of this investigation is to present a broad survey ...

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  • McLevige, S.M.; Muka, J.S.; Miller, N.R. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2003-03)
    The purpose of this work was to investigate and characterize the acoustic burst (“popping”) phenomenon occurring in household refrigerators shortly after compressor start-up. An experimental investigation began with ...

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  • Nino, V.G.; Hrnjak, P.S.; Newell, T.A. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2002-10)
    Aluminum multi-port microchannel tubes are currently utilized in automotive air conditioners for refrigerant condensation. Recent research activities are directed toward developing other air conditioning and refrigeration ...

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  • Hoehne, M.R.; Hrnjak, P.S. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2004-01)

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  • Traeger, K.M.; Hrnjak, P.S. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2005-06)
    This thesis focuses on microchannel heat exchangers, and the methods used to try and reduce the charge contained in them. First, four condensers were designed and manufactured with the same air side characteristics and same ...

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  • Zhang, X.; Tafti, D.K. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2000-04)
    The study classifies and isolates the effects of thermal wake interference that occurs in multilouvered fins. Inter-fin interference occurs between adjacent rows of louvers and is dominant at high flow efficiencies when ...

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  • Zhang, X.; Tafti, D.K. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2001-04)

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