Condensation heat transfer coefficients of HFC245fa on a horizontal plain tube

Abstract

In this study, condensation heat transfer coefficients (HTCs) of HCFC22, HCFC123, HFC134a and HFC245fa are measured on a horizontal plain tube 19.0 mm outside diameter. All data are taken at the vapor temperature of 39 with a wall subcooling temperature 3-8 . Test results show the HTCs of newly developed alternative low vapor pressure refrigerant, HFC245fa, on a smooth tube are 9.5% higher than those of HCFC123 while they are 3.3% and 5.6% lower than those of HFC134a and HCFC22 respectively. Nusselt's prediction equation for a smooth tube underpredicts the measured data by 13.7% for all refrigerants while a modified equation yielded 5.9% deviation against all measured data. From the view point of environmental safety and condensation heat transfer, HFC245fa is a long term good candidate to replace HCFC123 used in centrifugal chillers.

Measurements of the Thermal Conductivity of 1,1,1,3,3-Pentafluoropropane (R245fa) and Correlations for the Viscosity and Thermal Conductivity Surfaces

“…R245fa (1,1,1,3,3-pentafluoropropane) is a hydrofluorocarbon that is under consideration for use as a working fluid in organic Rankine cycles with low-temperature heat sources. − It also is of interest for use as a blowing agent and in centrifugal chillers . It is important to have accurate models for the thermophysical properties of working fluids to efficiently design equipment.…”

“…1−4 It also is of interest for use as a blowing agent 5 and in centrifugal chillers. 6 It is important to have accurate models for the thermophysical properties of working fluids to efficiently design equipment. Recently, a new equation of state has been developed by Akasaka et al 7 that provides thermodynamic properties for R245fa.…”

Compressed Liquid Viscosity of 1,1,1,3,3-Pentafluoropropane (R245fa) and 1,1,1,3,3,3-Hexafluoropropane (R236fa)

“…For example, R245fa and R236fa are excellent blowing agents to replace hydrochlorofluorocarbons for its desirable characteristics and could be used as working fluids in high-temperature heat pumps and power cycles . R245fa is also used as one component of refrigerant mixtures in centrifugal chillers for its environmental safety and high thermodynamic efficiency . In addition, these compounds may be suitable as cleaning solvents, release agents, and so on.…”

Free convection condensation of steam on horizontal wire wrapped tubes: Effect of wire thermal conductivity, pitch and diameter

“…It was reported that optimum fin spacing should be between 0.2 mm and 0.5 mm depending upon its fin height and fin thickness. Park et al [2] reported a comprehensive study of condensation heat transfer coefficients on horizontal plain tube using a wide range of available different refrigerants. Kumar et al [3] investigated the condensation heat transfer for steam and refrigerant R-134a on two different types of finned tubes as circular integral-fin tubes (CIFTs) and spine integral-fin tubes (SIFTs).…”