A generalized moving-boundary algorithm to predict the heat transfer rate of transcritical CO2 gas coolers.

• Generalized method presented to predict heat transfer rate and refrigerant temperature of transcritical gas coolers. • Based on the moving-boundary approach to separate supercritical and supercritical liquid regions. • New method shows higher accuracy in the predictions with extremely low computational efforts. • New model presents improved predictions for micro-channel type gas coolers compared to fin-and tube ones. • Source code of the method is provided in Python programming language as an appendix. This paper presents the development of a CO 2 gas cooler model using the moving-boundary (MB) method. The model aims to separate the gas cooler into two regions, supercritical and supercritical liquid, to predict the steady-state thermal heat transfer rate for air-type CO 2 heat exchanger. The model uses the latest correlations for refrigerant and air-side heat transfer coefficients and pressure drops. The experimental results of fin-and-tube type and micro-channel type gas coolers were used for model validation. The mean absolute error (MAE) of the gas cooler heating capacity predictions was approximately 4%, while the predictions of the outlet temperature of the refrigerant side were within ± 3 K. The present MB model also showed an improved computational time of up to 10 times faster compared to a discretized model, which can reduce the overall computational effort in the simulation of detailed transcritical cycle model. [ABSTRACT FROM AUTHOR]