Study On The Heat Transfer Performance Of Heat Exchanger In An Indirect Mobile Thermal Energy Storage System With Fins

The M-TES system would store industrial waste heat with energy storagematerial, and then it would be transported via container tank car to the user sites toprovide heat. Latent heat storage (LHS) using phase change material (PCM) offersmany benefts of large density of thermal storage, change from periodically emittedheat to constant-temperature heat source. The promise of a latent heat transportation(LHT) system using PCM for recovery of waste heat is particularly attractive. Butmost PCMs have unacceptably low thermal conductivity, leading to slow chargingand discharging rates, hence requiring heat transfer enhancement techniques. To solvethis problem, a longitudinal-fn-tube heat exchanger with latent heat storage materialswas proposed. We established two dimensional model of the container, and westudied the thermal and flow performance of the PCMs in the container with themethod of numerical simulation. We also established a mobilized thermal energystorage system(M-TES) to study heat storage performance of the heat exchanger.Different impacts caused by different heat transfer oil temperature and flow toerythritol melting were researched. Natural convection in heat transfer process wasalso analyzed. The research results show that:In the heat charging process, the presence of natural convection in the liquid areawould affect the gross heat transfer rate. We put more tubes at the bottom of the heatstorage container, which could strengthen the natural convection and accelerated themelting speed.In the heat discharging process, the heat transfer is controlled by both heatconduction and natural convection, but the natural convection would be more andmore week as the reducing of liquid PCMs.Rapid heat release speed of the container makes the heat storage materialperformance a subcooling phenomenon, the degree of the subcooling is about3～5℃,which is undesirable. We should take measures to prevent it, like put some specialmaterial in the PCMs.The temperature of the heat source would strongly affect the heat storageperformance of the heat exchanger. When in laminar flow area, the flow rates of the heat transfer fluid have a week influence on heat transfer.The heat exchanger showed a good performance in heat release process, wecould recover84%heat of the energy that to be stored in the PCMs.