Evaluating method of effectiveness of light energy's utilization based on service requirement

Energy conservation is becoming more and more important due to the shortage of energy sources. Because of the wide application of light, energy conservation of lighting is a very important issue to be studied. However, the evaluating method of the effectiveness of light energy's utilization, which is now widely adapted, concerns only about the conversion rate of energy. The amount of light energy which must be dissipated when a certain goal is to be met under a certain situation is ignored. As a result, a new evaluating method is introduced in this paper, which is based on the energy demand in actual situation. Firstly the inevitable energy consumption of lighting is found out with the help of energy flow analysis. Then the definition of energy requirement of lighting is given and the parameters which affect the energy demand of service of lighting have been confirmed. Based on this definition and parameters, an analysis model and the method to calculating the energy demand of service are provided. Finally redundancy of energy consumption is introduced to evaluate the lighting system.