| Summary: | 碩士 === 國立中山大學 === 機械工程研究所 === 86 === Air-cooled condensers are widely applied to small-scale air-conditioning system, Since condenser is a key component that decides the performance of the air-conditioning system.It is important to study the methods ot improve its heat transfer performance. Furthermore, to replace the traditional CFC refringerant is an imperative policy because of depletion of Ozone by traditional refrigerant. Therefore, the researchers have to pay more attention to the problems of condensing process and characters of new refrigerant in air-cooled condedser, and provide the reference data for developing and designing the R-134a air-conditioning system.
R134a as working fluid and air as coolong medium are used in this study to simulate the heat transfer process in an air-cooled condenser. The Plate, Lance and Louver types of externally finned exchangers are used as test sections. The effect of outside heat transfer coefficient, overall heat transfer coefficient and pressure drop are studied with the experimental data for varing parameters, such as mass lfux, inlet condensation temperatuer, inlet quality, cooling air velocity, and temperature. From the result of experiment, the Plate type condense has the lowest overall heat transfer rate while its pressure drop is highest. The Louver type has the lowest pressure drop.
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