不同碟式直接蒸汽热发电蓄热系统的性能分析

针对碟式太阳能斯特林热发电系统不具备储热功能而无法连续稳定发电的问题,提出了带蓄热的碟式直接蒸汽热发电系统。以25kW·h发电功率和8h蓄热时间为约束,设计了双罐间接蓄热、单罐斜温层蓄热2种显热蓄热系统以及双罐-潜热蓄热和单罐-潜热蓄热2种多级蓄热系统。以传热学、热力学和经济学原理为基础,对4种蓄热系统的热力学性能和经济性进行了对比分析。结果表明:双罐-潜热蓄热系统的蓄热性能最佳,系统火用]效率为77.67%;单罐-潜热蓄热系统次之,其系统火用]效率为61.69%;双罐蓄热系统和单罐斜温层蓄热系统的蓄热性能较差,其系统火用]效率分别为40.96%和32.83%。在经济性方面,双罐蓄热系统成本最高,单罐斜温层蓄热系统次之,双罐-潜热蓄热系统和单罐-潜热蓄热系统成本较低。综合热力学性能和经济性能,推荐碟式直接蒸汽热发电系统采用双罐-潜热蓄热作为蓄热方式。

Performance Analysis on Different Thermal Storage Systems for Dish Type Solar Power with Direct Steam Generation

Considering that the dish-Stirling solar thermal power system is unable to run continuously and steadily due to the lack of energy storage capacity,a dish type direct steam generation solar thermal power system with thermal energy storage was proposed.According to the demand of power generation capacity,we designed two kinds of sensible heat storage systems(i.e.,twotank molten salt storage,single-tank thermocline storage)and two latent heat storage system(i.e.,two-tank latent heat storage system and single-tank latent heat storage system).Based on the principles of heat transfer,thermodynamics,and economics,the thermal storage performance of four kinds of heat storage systems is compared and analyzed.The results show that the two-tank latent heat storage system has the best heat storage performance,and its exergy efficiency is77.67%.In terms of economy,the two-tank latent heat storage system has the lowest cost,and the single-tank latent rank the second,and the cost of the two-tank molten salt storage system is the highest.In two aspects of thermodynamic performance and economy,the two-tank latent heat storage system is recommended in the dish type solar power with direct steam generation.