TY - JOUR

T1 - Comparative evaluation of flow boiling heat transfer characteristics of R-1234ze(E) and R-134a in plate heat exchangers with different Chevron angles

AU - Kim, Dongwoo

AU - Lee, Dong Chan

AU - Jang, Dong Soo

AU - Jeon, Yongseok

AU - Kim, Yongchan

N1 - Funding Information:
This work was supported by Technology Innovation Program grant, funded by the Korean Government Ministry of Trade, Industry & Energy (No. 10052926 ).

PY - 2018/3/5

Y1 - 2018/3/5

N2 - In this study, the flow boiling heat transfer characteristics of R-1234ze(E) and R-134a in plate heat exchangers with different Chevron angles are measured and analyzed as a function of the mass flux, saturation temperature, vapor quality, and heat flux. The effect of the mass flux on the heat transfer and pressure drop of R-1234ze(E) is substantial. The heat transfer coefficient of R-1234ze(E) for a Chevron angle of 60° is approximately 3.7 times higher than that for a Chevron angle of 30° at high vapor qualities owing to the intensified turbulent flow. Moreover, for a Chevron angle of 60° the average heat transfer coefficient of R-1234ze(E) is on average 4.7% higher than that of R-134a due to its higher equivalent Reynolds number. However, the average pressure drop of R-1234ze(E) is higher than that of R-134a owing to the lower vapor density of R-1234ze(E). Finally, the correlations for the heat transfer and pressure drop of R-1234ze(E) are developed in the plate heat exchangers with different Chevron angles.

AB - In this study, the flow boiling heat transfer characteristics of R-1234ze(E) and R-134a in plate heat exchangers with different Chevron angles are measured and analyzed as a function of the mass flux, saturation temperature, vapor quality, and heat flux. The effect of the mass flux on the heat transfer and pressure drop of R-1234ze(E) is substantial. The heat transfer coefficient of R-1234ze(E) for a Chevron angle of 60° is approximately 3.7 times higher than that for a Chevron angle of 30° at high vapor qualities owing to the intensified turbulent flow. Moreover, for a Chevron angle of 60° the average heat transfer coefficient of R-1234ze(E) is on average 4.7% higher than that of R-134a due to its higher equivalent Reynolds number. However, the average pressure drop of R-1234ze(E) is higher than that of R-134a owing to the lower vapor density of R-1234ze(E). Finally, the correlations for the heat transfer and pressure drop of R-1234ze(E) are developed in the plate heat exchangers with different Chevron angles.

KW - Heat transfer coefficient

KW - Low GWP

KW - Plate heat exchanger

KW - Pressure drop

KW - R-1234ze(E)

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U2 - 10.1016/j.applthermaleng.2018.01.019

DO - 10.1016/j.applthermaleng.2018.01.019

M3 - Article

AN - SCOPUS:85044764775

SN - 1359-4311

VL - 132

SP - 719

EP - 729

JO - Applied Thermal Engineering

JF - Applied Thermal Engineering

ER -