Effect of surface roughness on the condensation of R-134a in vertical chevron gasketed plate heat exchangers

This paper presents the condensation heat transfer of R-134a flowing inside a chevron gasketed plate heat exchanger. The study focuses on the effect of surface roughness on the heat transfer coefficient and pressure drop. The stainless steel plate heat exchanger has a total length of 360 mm and total width of 100 mm. The experiment is conducted at a condensation temperature of 40-50 °C, a heat flux of 5-15 kW/m2, and refrigerant mass flux of 61-89 kg/m2s and plate surface roughness ranging between 0.594 μm and 2.754 μm. Unlike the increase in temperature, the increase in surface roughness and mass flux leads to an increase in the heat transfer coefficient and frictional pressure gradient. The increase in heat flux leads to a slight increase in heat transfer coefficient, but has no effect on the pressure drop. The thermal performance factors are in the range of 0.99-1.22 and 0.92-1.19 for roughnesses of 1.816 and 2.754 µm, respectively.