熔融盐斜温层混合蓄热单罐系统及其实验研究

经济型的蓄热系统设计对聚焦式太阳能热发电的市场竞争力影响效果非常明显,一个比较有效的方法就是采用斜温层蓄热。在斜温层蓄热单罐设计理念的基础上,提出了一种熔融盐斜温层混合蓄热单罐系统,该单罐的中段为斜温层显热蓄热,上部为高温壳管式相变换热器,下部为低温壳管式相变换热器。斜温层保障高低温熔融盐液在同一单罐内上下隔开,而高、低温壳管式相变换热器既增加了蓄热容量,又简化了熔融盐液的注入和出料结构。初步实验测定了该混合蓄热单罐系统的有效蓄热量,证实了其斜温层在放热与吸热循环运行中能稳定保持,并表明了该系统具有潜在的应用前景。

Scheme and experiments of a molten-salt hybrid thermocline thermal storage system

The cost-effective thermal energy storage will play an important role for the economic success of concentrating solar power plants.One option to significantly reduce costs is to use thermocline storage systems.Based on the idea of thermocline thermal storage,a molten-salt hybrid thermocline thermal storage system was developed in this paper,which was a single thermal storage tank,where a thermocline was in the middle section of the tank,a high-temperature PCM(phase change material)heat exchanger of shell and tubes was placed on the top of the tank and a low-temperature PCM heat exchanger of shell and tubes was placed on the bottom of the tank.The thermocline,a thermal gradient,potentially separated hotter molten-salt liquid from colder molten-salt liquid in the same tank. The high and low temperature PCM heat exchangers of shell and tubes would not only increase the thermal storage capacity of the system,but also simplify the molten-salt liquid charging and discharging structure.The preliminary experiments determined the amount of effective thermal storage capacity of the system and substantiated that the thermocline could keep stable during charging and discharging cycle and demonstrated the promising prospect of this thermal storage option.