Simulation study on frost formation characteristics on the surface of cold storage evaporator

Aiming at the frosting problem of evaporators in cold storage leading to significant decrease in heat transfer efficiency and damage to the cold storage, based on the theory of heat and mass transfer, combined with actual cold storage data, a modified relationship for the air heat transfer coefficient applicable to the frosting state of cold storage was established，and a dynamic model of frosting on the surface of the cold storage evaporator was constructed. The accuracy of the model was verified by using the frosting experimental platform on the surface of the cold storage evaporator.The effects of different return air temperature, return air humidity, and wind speed conditions on the growth of frost layer and the heat transfer efficiency of the evaporator were discussed. The results show that the frosting process on the surface of the evaporator can be accelerated by increasing the return air humidity and wind speed, as well as reducing the return air temperature. High humidity (0.6 g/kg) and low temperature (-22 ℃) conditions will increase the growth rate of frost layer thickness and the decrease rate of heat transfer efficiency of the evaporator. In high wind speed (4.4 m/s) conditions, the surface temperature of the frost layer is increased, and the driving force for frosting is reduced. The established frost formation model for evaporators is comparatively close to actual operating conditions, which provides a solid model foundation and theoretical reference for defrosting control strategies in cold storage.