塔式太阳能热发电太阳倍数及储热时长优化研究

Optimization design of solar multiple and thermal storage hour for DSG tower power generation

针对配备分离式吸热器的50 MW直接蒸汽(DSG)塔式太阳能电站,通过建立塔式电站系统耦合模型和经济性评价模型,探究太阳倍数和储热时长对其运行性能和标准发电成本(LCOE)的影响。结果表明:对于设计工况,当太阳倍数从1.0增加到3.0时,定日镜场光学效率随着太阳倍数的增加而降低,由67.8%降至62.3%,分离式吸热器热效率则基本不发生变化,朗肯循环效率也稳定维持在40.6%;对于年评价因子,电站年发电量和年容量因子均随着太阳倍数和储热时长的增加而增加;经优化计算,电站最低LCOE为0.214$/(k W·h),太阳倍数为2.7,储热容量为9 h,年容量因子为0.501,年发电量为219.5 GW·h;在最低LCOE下计算电站的月性能,发现提高太阳法向直射辐射强度(DNI)有利于提高容量因子和发电量。

For a 50 MWe direct steam generation （DSG）solar power tower plant with dual-receiver, the influences of solar multiple and thermal storage hour on its performance and levelized cost of electric energy （LCOE） were analyzed by establishing the tower power plant system coupling model and the economic evaluation model. The results show that, at design point, when the solar multiple varies from 1.0 to 3.0, the heliostat field efficiency reduces from 67.8% to 62.3% with the increasing solar multiple, while thermal efficiency of the dual-receiver varies little with the varying solar multiple and the Rankine cycle efficiency remains 40.6% for different solar multiples. For annual evaluation factors, both the annual electricity production and annual capacity factor increase with the solar multiple and the thermal storage hour. The optimization results show that the minimum LCOE is 0. 214 $/（kW·h） when the solar multiple is 2.7 and the thermal storage capacity is 9 h. The corresponding annual capacity factor is 0.501 and the annual electricity production is 219.5 GW·h. Monthly performance of the plant is achieved with the lowest LCOE and shows that high direct normal irradiation （DNI） is beneficial for high capacity factor and high electricity production.