塔式太阳能热电站系统仿真与分析

Simulation and Exergy Analysis of Solar Thermal Tower Plants

该文以八达岭1 MW塔式太阳能热发电系统为研究对象,建立了以水/水蒸汽为工质、带储能系统的塔式太阳能热发电■分析模型,并利用已有仿真平台模拟了电站在变工况下的状态参数。在此基础上,对整个电站进行了设计工况及变工况条件下■分析,辨识了各子系统热效率和■效率的变化规律。结果表明,设计工况下吸热器的损失率最高,可通过提高吸热器出口蒸汽温度来提高其效率。非设计工况下,定日镜场的效率受其与太阳相对位置的影响,其它子系统效率随太阳直射辐射强度(direct normal insolation,DNI)的增大而增大;充热过程中,随着进入储能系统蒸汽量的减少,储能系统和电站效率越来越高;放热过程中,储能系统释放的蒸汽流量对储能系统和电站的效率有显著的影响。

Taking the Badaling 1 MW solar thermal tower power plant as the research object, this paper builds the exergy analysis model for the solar power plant using water/steam as heat transfer fluid, and simulates the state parameters under variable conditions using existing simulation platform. Based on these, this paper further evaluates energy and exergy efficiencies of each sub-system and the overall plant, identifies change rules of energy and exergy efficiencies. The conclusion indicates that under designed condition receiver has the maximal exergy loss rate, which can be improved by increasing the outlet steam temperature of receiver. Under off-design conditions, the efficiency of heliostat is influenced by relative position between it and the sun, whereas exergy efficiencies of other sub-systems vary directly with direct normal insolation （DNI）. During the process of recharge, efficiencies of thermal storage system and overall plant increase as decrease of steam mass entering thermal storage system, while in the process of discharge, the variation of efficiencies corresponds to the flow mass released by thermal storage system.