Lighting calculations for LED systems

Pao Yue-kong Library Electronic Theses Database

Lighting calculations for LED systems

 

Author: Yao, Cheng
Title: Lighting calculations for LED systems
Degree: M.Eng.
Year: 2013
Subject: Light emitting diodes.
Light emitting diodes -- Energy consumption.
Hong Kong Polytechnic University -- Dissertations
Department: Dept. of Building Services Engineering
Pages: xv, 109 leaves : ill. (some col.) ; 30 cm.
Language: English
InnoPac Record: http://library.polyu.edu.hk/record=b2641123
URI: http://theses.lib.polyu.edu.hk/handle/200/7121
Abstract: Along with people's increasing awareness of energy conservation and environmental protection, lighting consumption, occupying a certain and stable percentage of total consumption, about 15%, leads to a new technological revolution. As a lamp substitute for new generation of domestic lamp, LEDs play a significant role undoubtedly. The advent and generalization of white LEDs, LED finally step into a period of civilian use. Along with the advantages such as eco-friendly, highly efficient, long service life, and harmless, LED also faces the disadvantage, the too much investment in early stage of new products. With the technology promoted and the cost reduced, the initial investment will drop naturally, at the same time, the benefits will grow gradually. However, public always cannot distinguish the concepts of luminaire efficacy and the lamp efficiency, which often mislead consumers, at the same time, it also confuse the some producers and sellers. Manufacturer always boast how outstanding their products are, while fail to regard actual experience of consumers. Indeed, due to the unclear definition and based on the present calculations, the procedure of calculating the indoor illuminance using calculation refer to utilization factor method may lead to chaos. Because the lamp and luminaire of LED is a whole that can hardly be separated, which will lead to overheating and unstable when it separated, therefore we cannot define the number of lumens emitted from lamp. In this paper, by analyzing the calculation refer to utilization factor, re-defines the concepts, which is applicable to LEDs calculation, and luminaire of calculation consistently, and get a correct calculation method to calculate utilization factors of LEDs. Through related calculations in EXCEL and simulations in DIALux of seven samples, several groups of data have been compared and analyzed. According to a series of analyses and calculations, this paper puts forward the relationship between the new utilization factor based on luminaire lumen output and the old utilization factor based on lamp lumen output. The new method is proved by author, and some comments are given.

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