Heat exchange during solid–liquid formic acid phase transitions in relation to the creation of cold storage batteries

The paper presents the results of experimental and numerical investigation of heat and mass transfer at the solid-liquid phase transition in spherical flasks of 66 mm diameter with formic acid as heat-accumulating substance. The average value of heat flux density was about 750÷800 W/m2 and corresponds to 15 min of melting process time. By this moment about 60% of the phase change material (PCM) passes into the liquid state. Experimental and calculated by the null model values of heat flux density and volume fraction of formic acid liquid phase differ not more than by 7%. The uncertainty of the calculated melting time of PCM is about 10%. The data obtained in the work can be used for the estimation of parameters of cold storages with formic acid as a heat-accumulating substance located in spherical containers of 66 mm diameter. The results of this research show the potential of applying faster null-dimensional models for calculations of heat exchange intensity at melting of PCM in spherical containers and operating time of container-type cold storages. The results of work can find application in systems of air conditioning while using cold storages of container type with formic acid for removing peak loads.