The purpose of this paper is to develop a method for showing explicitly how electric lighting systems work applying the concepts of entropy and exergy. The proposed method has been tested for a room which is enclosed by the surfaces having medium or high reflectance and Illuminated by an electric lighting system with fluorescent lamps. The result shows that changing merely the reflectance of interior wall surfaces brings about a large reduction in the input exergy, namely the reduction of entropy generation. This confirms that it is essential to design an exergy-efficient room space for providing enough brightness in addition to manufacturing and using exergy-efficient fluorescent tubes and fixtures.
