抄録
By means of the method to determine a turning-off depth in which one can turn off an electric lighting to utilize daylight in a perimeter for the energy savings, turning-off depths were found for various turning-off ratios actually for standardized office rooms with side-lit windows, typical electric lightings and simple sun-break overhangs. With these combinations of turning-off depth and ratio, saving factor of electric energy for lighting was calculated, which is defined as the ratio of electric energy for lighting saved by turning-off to the energy consumed by full lighting. Then, a combination of the turning-off depth and ratio maximizing factor of electric energy for lighting exists for each standard office room. These are termed an optimum depth and its ratio in this paper. This combination was obtained and the effect of length of a sun-break overhang on these values was studied.
