Performance Analysis of a Brazed Plate Heat Exchanger During Condensation of R1233zd(E)

Abstract

This paper focuses on the validation of a brazed plate heat exchanger (BPHE) model that acts as the condenser of a novel in-rack cooling loop. In the proposed system, the primary fluid enters as a saturated vapor, while the secondary fluid enters as a subcooled liquid flowing in a counterflow configuration. The model augments an existing general technique for simplicity and computational efficiency and is applied to the condensation of a low-pressure, environmentally friendly refrigerant, i.e., R1233zd(E). The model analyzes the heat transfer and pressure drop values of both fluids in the heat exchanger and uses these results to predict the heat exchanger duty and exit temperature and pressure of both fluids. The model predicts the values of fluid output properties along with heat exchanger duty to within 20% of experimental measurements. The validated model is then used to assess the magnitude of the heat transfer coefficient and friction factor attained on both fluid sides of the heat exchanger, including relatively uniform water-side heat transfer coefficient, a substantial (30%–80% of overall flow length) region of two-phase condensation, and a minimum refrigerant-side friction factor in the subcooled regime.