Enhancing cold retention in small refrigerators using phase change materials: Numerical study and thermal modeling

Small refrigerators, active coolers and portable thermal containers are widely used for transporting food products, temperature-sensitive medicines and biological samples. Unfortunately, their thermal autonomy is often limited, particularly during power outages or prolonged exposure to high ambient temperatures. This study explores the integration of phase change materials (PCMs) as a passive method of extending cold storage life. A transient thermal model and numerical simulations were developed to test the performance of different PCMs with melting temperatures between 25 and 30 °C and latent heat capacities of 150 to 260 kJ/kg, positioned in the inner walls of small refrigerators with volumes ranging from 20 to 125 L. The results indicate an increase in thermal autonomy of 45 to 120%, depending on the mass and location of the MCP, as well as a significant reduction in internal temperature fluctuations. The proposed approach offers robust and energy-efficient solutions for portable cold storage and passive refrigeration applications.