Performance analysis of parallel flow heat exchanger based on water and R134a

This study constructs and validates a heat transfer model of a PFHE applied in data center cabinet cooling systems, using water and R134a as working fluids. By comparing with experimental data, the specific impacts of the two working fluids on the heat exchanger performance are thoroughly analyzed. Findings indicate that compared to water, R134a demonstrates superior uniformity in outlet air temperature and its cooling capacity is 1.23 to 2.27 times that of water. However, the pressure drop in the two-phase heat exchange of R134a is generally higher than that of water during single-phase heat exchange. Furthermore, this paper provides a detailed analysis of the effects of working fluid flow rate, air flow rate, inlet air temperature, and flat tube thickness on cooling capacity, pressure drop, outlet air temperature, and coefficient of performance (COP).