Irradiance

Calculate solar irradiance (W/m2) and radiation (kWh/m2) at each time step provided by a wea file.

The fundamental calculation of this recipe is the same as that of Annual Daylight Enhanced in that a detailed accounting of direct sun is computed at each time step. However, the recipe computes broadband solar irradiance in W/m2 instead of visible illuminance in lux.

The detailed matrices of W/m2 at each time step are stored under results/total. Detailed matrices of just the direct component (W/m2) are output to results/direct. The following values are also recorded for each sensor point under the metrics folder:

• average_irradiance: The average irradiance in W/m2 over the Wea time period
• peak_irradiance: The highest irradiance value in W/m2 during the Wea time period
• cumulative_radiation: The cumulative radiation in kWh/m2 over the Wea time period

The peak_irradiance value is suitable for assessing the worst-case solar load on cooling design days or the highest radiant temperatures that occupants might experience in over the time period of the Wea.