Submitted by elsbeth on Tue, 2009-10-27 17:36

Intensity of solar radiation

 

The intensity of the sun’s rays is the amount of incident sunlight. It is not a constant. It depends on the weather and the time of year and is different at different times of the day. It is assumed that in one hour, 1000 W per m² (=1 kWh/m²) strike the surface of the earth. In the Netherlands, the total annual amount of sunlight is around 1000 hours of full sun (= 1000 kWh/m2). In the winter, there is around 0.5 kWh/m2 per full hour of sun, a figure which is 10 times greater in the summer, at 5 kWh/m2. The amount of solar irradiation also varies from region to region. For instance, the coastal areas of the Netherlands receive more sun than the Eastern part of the country.