Experimental study on the solidification process of fluid saturated in fin-foam composites for cold storage

Cold storage can effectively turn electricity to cold energy during off peak hours and reduce electricity peak load by supplying cold energy for air conditioning. Solid-liquid phase change rate is seriously encumbered by the relatively-low thermal conductivity of phase change materials (PCMs). A novel fin-foam structure was established to enhance solidification heat transfer and the solidification characteristics were experimentally explored. An experimental system visualizing solid-liquid interface and temperature monitoring was built. The parameters of fin-foam structure, including fin sizes, fin pitch and number were investigated experimentally. Particular attention was paid to justifying the local thermal equilibrium state via measuring temperature on metallic ligament surface and the saturating fluid in pore space. Results showed that inserting fins into metal foam can make a promotional improvement on solidification rate of water by 28.35%. The solid-liquid interface became locally curved after inserting fins. Thermal adhesive and insulation adhesive did not affect the accuracy at pore-scale temperature measurement. Solidification process can be further enhanced through increasing fin width and number rather than fin pitch.