Category: Solar Technologies for Buildings

Light measurements

The human eye is capable of comparing illuminances of adjacent surfaces with an accuracy of about 2%. This was quantitatively first used in the so-called grease photometer of Bunsen, where luminous intensities were determined by shining two light sources from opposite sides on a paper screen partly covered with grease. If one light source has […]

Distribution of the luminous intensity of artificial light sources

The luminance of lamps or lights is rarely constant in all directions in space. Luminous intensity distributions are indicated by the manufacturers in polar diagrams in different sections. Usually the absolute luminous intensity in candelas refers to a fixed lamp light-flux. If in Equation (8.14) the luminance of the sender surface is replaced by the […]