Preferred Illuminances on Surrounding Surfaces in Relation to Task Illuminance in Office Room Using Task-ambient Lighting

Abstract

Comfortableness in various spaces is recently gaining priority. For comfortable lighting in a desk work area, visual comfort in the environment as well as good visual performance are required during a long desk work with visual tasks such as reading and writing documents. Preferable illuminance and luminance on surrounding surfaces in relation to the task (on the desk) illuminance should be determined appropriately. Since general lighting is usually used as office lighting, the previous paper clarified the preferred wall illuminance and luminance in relation to desk illuminance. On the other hand, task-ambient lighting has been proposed to save energy. In this paper, the following items are clarified with respect to the task-ambient lighting.
(1) Preferred ambient illuminance in relation to task illuminance
(2)Preferred wall illuminance in relation to task illuminance
Further, with the use of task-ambient lighting based on the results above, even with energy-saving ambient illuminance, the ratio of consumed wattage per worker between general lighting and task-ambient lighting, is obtained through a simple calculation; the result reveald that the power saving amount to as much as 40-55%.