Experimental study on heat transfer enhancement of heat exchanger in indirect mobilized thermal energy storage system with fins

To recover waste heat for the distributed users, an indirect mobilized thermal energy storage(M-TES) system is designed incorporating a medium temperature phase change material(PCM) erythritol. Because the low thermal conductivity of the PCM, the copper tube that with double straight fins is chosen to help enhance the heat exchange. The thermal characteristics in the system are analyzed using temperature time curves. The investigation shows that the temperature of the PCM rises rapidly in the solid sensible heat stage in the heat storage process, but there is almost no temperature change in the latent heat stage. The natural convection can make the PCM melt faster. The melt process of the PCM takes 210 min. The temperature of the heat rature of the waste sousesource has influence on the charging time and the temperature gradient of the PCM. In the heat release process, the PCM shows sub-cooling phenomenon. The investigation also shows that 16 790 kJ of heat is released in the initial 120 min of discharging process that accounts for 84% of heat capacity of the M-TES container, which can heats 0.115 m3 of water from 10 °C up to 55 °C. The system shows a good performance in energy storage process. It makes the mobile energy storage car can be truly used for recover industrial waste heat. © 2013 Journal of Mechanical Engineering.