R32 heat transfer coefficient during condensation in a mini channel multiport tube.

Number: pap. 2488



The use of micro- and mini-channels in heat exchanger has increased in recent decades. They contribute to increasing efficiency and to reducing refrigerant charge and compactness of heat exchangers. The aim of this study is to experimentally determine heat transfer coefficient in mini-channels two-phase flow processes with the low GWP refrigerant R32 and compare it with the values provided by some of the correlations encountered in the existing literature. In the existing literature there are a few publications studying the refrigerant R32. R32 has medium flammability, classified as A2 by ASHRAE. European air conditioning manufactures point to use R32 instead of R410A. R32 has lower global warming potential (GWP = 675) than R410a (GWP = 2088). Environmental improvements must be also considered. R32 is a single component refrigerant so recycling is easier than R410A process; also R32 is safer than R410A by NFPA 704 classification; with R410A a breathing apparatus is required in case of accident. On the other hand, R410A flammability is lower than R32 because of the addition of R125. An installation for the study of condensation processes has been constructed at the “Technical University of Cartagena”, Spain. The more relevant results of heat transfer coefficient will be presented in this paper. The analysed data have been measured for R32 flowing through aluminium square multiport tubes with a hydraulic diameter of 1.16 mm and compared with R410A. The influence of saturation temperature (or pressure), flow velocity, and vapour quality in heat transfer coefficient and frictional pressure gradient have been studied. The values considered for these variables are: saturation pressure corresponding to 30, 35, 40, 45, and 50°C; flow velocities from 100 to 800 kg/(s•m2); vapour quality from 0.05 to 0.9.

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  • Original title: R32 heat transfer coefficient during condensation in a mini channel multiport tube.
  • Record ID : 30013229
  • Languages: English
  • Source: 2014 Purdue Conferences. 15th International Refrigeration and Air-Conditioning Conference at Purdue.
  • Publication date: 2014/07/14


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