The concept of luminous efficacy, the ratio of daylight illuminance to solar irradiance, is investigated for use in building energy analyses. Horizontal and vertical luminous efficacies are evaluated as functions of solar altitude, cloud condition, atmospheric extinction coefficient, turbidity, and season. Based on sky measurements made at the National Bureau of Standards, values of luminous efficacy for total, diffuse, and direct beam radiation are presented.
Citation: ASHRAE Transactions, 1985, vol. 91, pt. 1A, Chicago, IL
Product Details
- Published:
- 1985
- Number of Pages:
- 13
- File Size:
- 1 file , 1.3 MB
- Product Code(s):
- D-CH-85-2867
