Heat transfer characteristics of the fin-tube three-fluid heat exchanger in cold warehouse with cold storage

To address the challenges of high manufacturing power consumption and the cost of components in photovoltaic cold warehouses, this study integrates the evaporator and cold-release heat exchanger into a novel three-fluid heat exchanger, which considers variable thermophysical properties, aiming to significantly reduce metal usage and cost. The key innovations include a generalized shape factor model for adverse heat conduction and a photovoltaic cold-storage system centered on a three-fluid heat exchanger. Furthermore, the influence of airflow regime on heat transfer is considered, and the critical conditions for adverse heat transfer are identified through experimentation. Results show that: (1) With the inlet velocity of air increased, the heat transfer rate increased by 55.4%, while the pressure drop of air increased by 5.5 times. (2) With the fin spacing increased, the total heat transfer rate decreased by 8.8%, but the pressure drop of air significantly decreased by 36.9%. (3) Under a multi-flow coupled mode, when the temperature difference between air and water is below 0.59 °C, the water does not absorb heat from the air but instead transfers heat to the refrigerant through the fins. (4) A generalized shape factor model achieves significantly improved fitting accuracy, with residuals within ±50 W. (5) The installation of each three-fluid heat exchanger decreased the configuration cost by 63.1%, decreased the carbon emission by 197.6 kg, and saved 194.2 kWh of electric energy. The fin-tube three-fluid heat exchanger model is highly significant for decreasing the cost and carbon emission of ice-storage cold warehouse systems.