Numerical Simulation And Experimental Study On Thermal Performance Of Multiple-pipe Heat Storage

Driven by the rapid development of global industry, massive energy consumptionwould possibly lead to an unprecedented energy crisis. Energy conservation andconsumption reduction have become one of the world’s top concern. As a kind of newenergy technology aimed at improving energy efficiency and protecting the environment,heat storage technology is becoming a research hotspot. Among various heat storetechnologies, latent thermal storage has been widely applied due to its characteristics ofmaximal heat storage density, strong heat accumulation ability, small volume change, etc.Currently, phase change materials (PCM) and thermal storage structure are twosignificantly interested subjects within the field of heat storage technology.Taking paraffin as PCM, the mathematical model and physical model of simulationobject are established based on theoretical analysis together with appropriate assumptions.Then FLUENT is utilized for numerical simulation, allowing the analysis of temperaturefield distribution during the heat storage and release processes in multitube regeneratorfilled with pure paraffin and paraffin/expanded graphite(EG) composite. Simulationresults show that the addition of EG not only reduces the heating and exothermic time, butmakes the temperature field distribution more uniform and reasonable in the heataccumulator. Finally, by designing the experimental procedure and building a test bench,heat storage and release experiments are done. Temperature data of PCM in differentpositions is collected; meanwhile, heat charge and discharge performance of the phasechange accumulator is also analyzed. Comparing the numerical simulation results with theexperimental data, it is found that the temperature distribution within the phase changeaccumulator is anisotropic. However, due to simulation limitations and some inevitablefactors such as heat loss during the experiment, it is reasonable that there is deviationbetween the simulation results and the experimental data.Through numerical simulation and experimental research on multiple-pipe heatstorage, valuable references are provided for the future design and optimization of phasechange heat storage.