An experimental data-driven charge model for round-tube-plate-fin heat exchangers using low-GWP refrigerants

Heat pumps can be switched between cooling and heating mode, requiring accurate charge modeling capabilities to enable the design of heat exchangers for near optimum efficiency in both operating modes. The charge modeling tools also require high-fidelity experimental validation data to tune their predictions. However, little experimental charge validation data is available in the open literature. This study addresses this need by providing complete, high-fidelity, experimental charge data of Round-Tube-Plate-Fin Heat Exchangers (RTPF) with ±2.2% of relative charge-measurement uncertainty and 0.8% of charge-measurement repeatability. In addition to R410A, charge data on two low-Global Warming Potential (GWP) refrigerants, R1234yf and R468C, is additionally collected. Furthermore, an accurate data-driven charge model is developed, tuned by the high-fidelity experimental charge data, with 12.3%, 12.8%, and 12.9% of the Mean Absolute Percentage Error (MAPE) based on the Taitel–Barnea, the Zivi, and the Baroczy void-fraction model, respectively. This experimentally validated charge model can contribute to enabling effective designs of heat pumps with high-accuracy charge predictions.