Performance And Application Research Of Shell-and-tube Ice Storage Tank

Thermal energy storage air conditioning system is an effective demand-side management strategy for shifting electric loads from on-peak to off-peak hours and achieving valley filling and load shifting. Closed-circuit external-melt ice-on-coil thermal storage system would ameliorate the conventional external-melt ice-on-coil thermal energy storage system to attain low-temperature economy. In this paper, shell-and-tube external-melt ice-on-coil tank is proposed to form the closed-circuit system. Both mathematical and experimental research concerning such key problems of the tank as optimization of its design, cooling charge and discharge performances, etc. was undertaken in an attempt to boost its application. This research will accelerate the development of low-temperature supply air and ice thermal storage technologies in China. The following content was researched in this paper:The mechanism and structure of shell-and-tube external-melt ice-on-coil tank and closed-circuit external-melt ice-on-coil thermal storage systems were proposed.Based on a proper definition of its configuration, a simple analytical model to predict the cooling charge and discharge performances of shell-and-tube ice tanks that contains such characteristics that ice forms and melts in closed limited place. The quasi-steady assumption was made, and thermal resistance network theory and energy balance method were employed in the modeling. The control differential equations describing the heat transfer during cooling charge and discharge were resolved by finite difference calculus.A shell-and-tube ice tank was designed and manufactured, and a closed-circuit external-melt ice-on-coil thermal storage system experimental plant was constructed to test its characteristics during operation. Analysis of experiment results was made to study how each parameter influence the general performance of the tank for the purpose of guide its design and operation. Cooling charge and discharge prediction by the model and experimental results was compared to validate the accuracy of the model.The system scheme of closed-circuit external-melt ice-on-coil thermal storage applied in cold air distribution dedicated outdoor air system of hospital operating room was presented. In a hospital operating room air conditioning case, configuration of the demanded shell-and-tube external-melt ice-on-coil tank is optimized utilizing the predication model. Energy consumption and economy analysis were undertaken. The result of the analysis showed that the application of shell-and-tube external-melt ice-on-coil tank in cold air distribution dedicated outdoor air system of hospital operating room was feasible and economical.