Uncertainty Analysis on Prediction of Heat Transfer Coefficient and Pressure Drop in Heat Exchangers Due to Refrigerant Property Prediction Error

Numerical simulation is extensively used in heat exchanger design and performance evaluation. While evaluating potential working fluids, pure fluids and fluid mixtures with different component combinations and fractions are compared based on simulation results. Two of the challenges while conducting such studies are the uncertainties of refrigerant properties and the applicability of empirical heat transfer and pressure drop correlations. Pure refrigerant property uncertainties are associated with experimental testing technique. The uncertainties of refrigerant mixtures are significantly higher when mixing rules are applied due the lack of measured data. Most of the empirical correlations are developed for certain refrigerants with a limited range of applicability of fluid states and tube geometry. Therefore, it is essential to understand the uncertainties in heat transfer coefficient and pressure drop calculations with different fluids. This paper presents a sensitivity analysis of heat transfer and pressure drop correlations for both in-tube condensation and evaporation cases. Multiple refrigerant such as R1234yf, R1234ze(E), R134a, R32, R410A, R445A, D2Y60 and L41a are analyzed based on commonly used heat transfer and pressure drop correlations from the literature. The parameters of the analysis are the thermodynamic and transport properties of the refrigerants. This study should be helpful to researchers and engineers in correlation selection during heat exchanger simulation and in understanding the potential prediction uncertainties while evaluating new fluids.