In Tube Condensation Heat Transfer and Pressure Drop for R454B and R32—Potential Replacements for R410A

Journal Article · Thu Jul 21 00:00:00 EDT 2022 · International Journal of Refrigeration

DOI:https://doi.org/10.1016/j.ijrefrig.2022.07.019· OSTI ID:1879951

Jajja, Saad ^[1]; Nawaz, Kashif  ^[1]; Fricke, Brian  ^[1]

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1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

The heating, ventilation and air conditioning (HVAC) industry in the United States seeks near-term alternative refrigerants to replace R-410A in unitary equipment. Two potential replacement refrigerants are R-454B and R-32. It is of interest to investigate the capability and accuracy of existing heat exchanger design methods when applied to these replacement refrigerants. To that end, this work presents empirical condensation quasi-local heat transfer coefficient and pressure drop data for R-454B and R-32. These data were obtained in a $$\frac{3}{8}$$ in. (9.52 mm) outside diameter (OD) smooth copper tube with a wall thickness of 0.032 in. (0.81 mm). The experimental variables and their ranges included refrigerant absolute pressure ( $1960\le P_{abs}\le 3196$ kPa), condensation temperature ( $35\le T_{cond}\le 50$ °C), mass flux ( $100\le G\le 200$kg m^-2 s^-1), vapor quality ( $0\le x\le 1$), and heat flux ( $32.9\le q^{″}\le 62.97$ kW m^-2). It was found that the heat transfer correlation developed by Cavallini et al. Cavallini et al. (2006) predicted the experimental condensation heat transfer data, for both R-454B and R-32, with the greatest accuracy. Using the Cavallini et al. correlation, it was found that the mean absolute percentage error (MAPE) was 10.5% and 15.1% for R-454B and R-32, respectively. Additionally, the pressure drop correlation developed by Friedel Friedel (1979) predicted the experimentally determined pressure gradient with a MAPE of 7.7% and 5.5% for R-454B and R-32, respectively. These results will assist the practicing thermal engineer to choose the most appropriate design correlation for these near-term replacement refrigerants.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1879951
• Alternate ID(s): OSTI ID: 1896512
• Journal Information: International Journal of Refrigeration, Vol. 144; ISSN 0140-7007
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
Condensation
Heat Transfer Coefficient
Pressure Drop
R-410A
R-454B
R-32