Knowledgebase
Do annual daylighting calculations use the EPW weather file?
Posted by Luis Sousa on 10-Jul-19 05:53 PM

Question:  Do annual daylight simulations use the weather file associated to thermal model on site level?

Answer: Yes, the weather file is used to produce a matrix of sky patch values using the Perez all weather model. The input file contains a short header with the site parameters followed by the month, day, standard time, direct normal and diffuse horizontal irradiance values, one time step per line (8760 lines).


Technical: The EPW file is converted to Radiance format using the epw2wea converter for use with the RADIANCE gendaymtx program that is described at:

https://www.radiance-online.org/learning/documentation/manual-pages/pdfs/gendaymtx.pdf