太阳辐射对电站直接空冷系统运行的影响

对我国西北地区某135MW直接空冷机组的凝汽器的全年太阳辐射进行计算,对相应空冷凝汽器运行的影响进行了理论分析,并在假定汽轮机排汽量不变、环境温度为月平均日温度的条件下,根据21年(1979～2000)间数据统计,得到太阳辐照量对空冷凝汽器热负荷与背压的影响变化规律:凝汽器的表面方位角的变化对由太阳辐射引起的月平均附加热负荷的影响比较小;1～5月期间由太阳辐射引起的月平均附加热负荷升高,5月时达到最大值,为371.75kW,而后逐步降低,其变化趋势与全年月平均日日照时数的变化趋势基本一致;假定方位角为零时,相同环境温度下凝汽器由太阳辐射引起的月平均附加热负荷增加而导致背压变化在1～7月间增加,7月时达到最大值,为0.2097kPa;8～12月相应的背压变化会减弱,其变化趋势与全年月平均日环境温度的变化趋势大致相同,这说明背压主要受环境温度的影响。

Influence of solar radiation on operation of a direct air-cooling condenser system

For the condenser in a 135 MW direct air-cooling condenser system in Northwest China, the effect of solar radiation on the operation of the condenser system was investigated theoretically.Based statistical data over a period of 21 years (1979 to 2000),the monthly averaged midday solar radiation was obtained, and its effect on the heat load and back pressure were investigated based on the constant turbine outflow and monthly average day temperature of enviroment.The variation of azimuthal angle has little effect on the monthly average heat load from the solar radiation.The monthly average heat load from the solar radiation increases in a 5-month period (January to May)reaching 371.75 kW in May and then decreasing.The changing trend is consistent with that of the monthly average day sunshine time.For the azimuthal angle of 0°, the back pressure increases over a 7-month period (January to July)at the same environmental temperature, with the maximum increment reaching 0.2097 kPa in July, and then decreases over a 5-month period (August to December）.The changing trend is consistent with that of the monthly average day temperature of environment, and the back pressure is significantly affected by the environmental temperature.