Numerical simulation and comparative analysis of heat transfer performance of evaporators based on dual-source heat exchange

The present study undertakes a numerical simulation and comparative analysis of the heat transfer performance of a dual-source heat exchanger evaporator. The analysis focuses on selecting refrigerant R410A and ethylene glycol as the circulating mediums within the evaporator. The investigation evaluates the heat transfer performance of the dual-source heat exchanger evaporator under varying velocities of both the refrigerant and ethylene glycol. Furthermore, the study juxtaposes the heat transfer efficiencies of finned-tube and light-tube heat exchangers within low-temperature environments. The findings indicate that the convective heat transfer coefficient of the finned-tube configuration is consistently lower than that of the light-tube counterpart across different refrigerant velocities. The maximum observed discrepancy, i.e., the maximum difference between the observed and the theoretical values, is $\mathbf{1 . 6 8} \mathrm{kW} /\left(\mathrm{m}^{2} \cdot \mathrm{~K}\right)$ when the refrigerant velocity is $0.6 \mathrm{~m} / \mathrm{s}$. Furthermore, calculations conducted in the single-phase zone reveal that ethylene glycol’ s convective heat transfer coefficient at a velocity of $1.1 \mathrm{~m} / \mathrm{s}$ measures $2424.02 \mathrm{~W} /\left(\mathrm{m}^{2} \cdot \mathrm{~K}\right)$. Furthermore, it was ascertained that the refrigerant outlet gas phase volume fraction at a glycol velocity of $0.5 \mathrm{~m} / \mathrm{s}$ is 0.6.