Abstract
This study investigates the evaporation heat transfer coefficient and two-phase frictional pressure drop of refrigerant mixture R1234ze(E)/R32 at various R1234ze(E) composition ratios in a brazed plate heat exchanger. The heat transfer coefficient of R1234ze(E)/R32 shows a concave curve as a function of composition ratio owing to the temperature glide of the mixture, whereas the two-phase frictional pressure drop increases exponentially with respect to the composition ratio. In addition, the averaged evaporation heat transfer characteristics of R32, R1234ze(E)/R32 (85%/15%), and R1234ze(E) are compared by considering the European Union (EU) regulations for global warming potential (GWP). For regulation phase A (GWP > 750), R32 exhibits the best heat transfer performance, whereas for regulation phase B (GWP > 150), R1234ze(E) shows a favorable averaged heat transfer coefficient compared to R410A and R134a. Finally, based on the measured data, correlations for the Nusselt number and two-phase friction factor for R1234ze(E)/R32 are derived as a function of composition ratio using a nonlinear interpolation method with the pre-developed correlations for pure R1234ze(E) and R32.
Original language | English |
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Pages (from-to) | 216-226 |
Number of pages | 11 |
Journal | International Journal of Heat and Mass Transfer |
Volume | 140 |
DOIs | |
Publication status | Published - 2019 Sept |
Bibliographical note
Publisher Copyright:© 2019 Elsevier Ltd
Keywords
- Heat transfer
- Plate heat exchanger
- Pressure drop
- R1234ze(E)
- R32
- Refrigerant mixture
ASJC Scopus subject areas
- Condensed Matter Physics
- Mechanical Engineering
- Fluid Flow and Transfer Processes