该文研究太阳光照条件、环境温度、风速、风向等因素对塔式太阳能热发电熔盐吸热器整体热效率和散热损失的影响规律,讨论吸热器的运行策略及其对系统效率的影响。吸热器的运行受风速和入射能量的影响较大,受风向和环境温度的影响较小。额定出口温度模式下,当风速超过7 m/s时,对流散热损失超过辐射散热损失。风速对吸热器局部对流散热损失的影响较大,但对局部辐射散热损失的影响非常小。在额定出口温度模式下运行时,尽管吸热器热效率较低,但其效率和整个系统的能量利用率比额定质量流量模式更高。当太阳直射辐射（DNI）相对稳定或变化幅度较小时,宜采取额定出口温度运行模式,此时若入射能量不低于设计值的80%,系统效率最大提升2%;若入射能量从设计值的80%降低至30%,系统效率提升值从2%增大至9%。当DNI剧烈波动时,宜采取等效额定出口温度运行模式。
Abstract
This article studies the influence of environmental conditions on overall thermal efficiency and heat loss of molten salt receiver for Concentrating Solar Power, including concentrated incident energy, ambient temperature, wind velocity and wind direction. Operation strategy of the receiver and its influence on system energy efficiency are discussed. The operation performance of the receiver is mainly affected by wind velocity and concentrated incident energy. Wind direction and ambient temperature, however, do not have significant influence on it. If wind velocity is over 7 m/s, the overall convective heat loss under rated outlet temperature mode surpasses the radiative heat loss. The local convective heat loss of the receiver is greatly influenced by wind velocity, while the local radiative heat loss is almost independent of it. When operated under rated outlet temperature mode, thermal efficiency of the receiver is lower. However, its exergy efficiency and the overall energy efficiency of the whole system are higher than that of rated mass flow rate mode. Compared to rated mass flow rate mode, it is recommended to adopt rated outlet temperature mode when direct normal irradiance（DNI） remains stable. In such case, the enhancement of overall system energy efficiency will be up to 2% if concentrated incident energy reaches 80% and above of the designed value. And the enhancement increases from 2% to 9% when concentrated incident energy decreases from 80% to 30% of the designed value. It is noted that an equivalent rated outlet temperature mode can be adopted when （DNI） fluctuates violently.
关键词
塔式太阳能热发电 /
数值计算 /
散热损失 /
效率分析 /
熔盐吸热器 /
运行策略
Key words
solar power tower /
numerical simulation /
heat loss /
efficiency analysis /
molten salt receiver /
operation strategy
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基金
国家自然科学基金（51776186）; 浙江省杰出青年基金（LR20E060001）
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