IIR document

Condensation characteristics of R134A and R404A in horizontal micro finned tubes.

Number: pap. n. 320

Author(s) : KUKREJA R., SINGH S.

Summary

Internally Micro finned (MF) tubes are being used presently in the Condensers and Evaporators of Unitary air conditioning systems. In the present study, condensation characteristics of HFC refrigerants, R-134a and R-404A have been investigated experimentally inside horizontal smooth and MF tubes (OD 9.52mm) of 15° and 18° helix angle respectively, in mass flux range of 200-600 kg/m2s with vapour quality varying between 0.1-0.9 at condensation saturation temperatures of 35°C and 40°C. The calculated quasi-local condensation HTCs for R-134a and R-404A inside MF tubes are 1.21-1.82 and 1.18-1.54 times higher and corresponding frictional PD are 1.97-2.56 and 1.71-2.22 times higher compared to that obtained for ST. The HTCs and frictional PDs for refrigerant R-134a are higher compared to refrigerant R-404A. A new heat transfer correlation has been proposed. The overall uncertainty in the heat transfer coefficient varied between 5% to 15%.

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Details

  • Original title: Condensation characteristics of R134A and R404A in horizontal micro finned tubes.
  • Record ID : 30026405
  • Languages: English
  • Source: Proceedings of the 25th IIR International Congress of Refrigeration: Montréal , Canada, August 24-30, 2019.
  • Publication date: 2019/08/24
  • DOI: http://dx.doi.org/10.18462/iir.icr.2019.0320

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