POTENTIAL ENERGY SAVINGS OF LED FLAT LIGHTING

摘要

Objective:rnNowadays conventional fluorescent lighting is replaced with LED Flat Lighting because they are thoughtrnto offer many advantages, including luminaires efficacy, tenability of the spectrum, energy savings,rnappearance and quality of lighting, environmental benefits and cost effectiveness. In order to confirmrnLED Flat Lighting advantages, we should be evaluated using field test like the office environment. Inrnthis paper, we investigated the lifetime and estimated energy savings and payback of LED Flat Lighting.rnMethods:rnThe Study aimed at identifying the lifetime and estimated energy savings and payback of LED Flat Ligh-rnting. The identification process followed a step-by-step approach, as follows. In the first part of the ex-rnperiment, LED Flat Lightings are installed in positions equivalent to Lightings in office environment. Wernmeasured the Relative illuminance of LED Flat Lightings during 6000 hours using an illuminance meter.rnAnd we determined assuming their usual lifetime. In the second part of experiment, Cost Analyses arernrealized on the LED Flat Lighting and compared with conventional fluorescent Lighting in terms of ins-rntallation, operation, lifetime and maintenance costs at equivalent light output. The last measurementsrnwere focused on change of optical property during 6000 hours: total luminous flux, luminous efficacy, lu-rnminous intensity distribution. Initial optical performance of LED Flat Lighting was compared with respectrnto optical performance of 6000 Operating hours later.rnResults:rnConditions of LED flux degradation tests and lifetime are relying on the standard IESNA LM-80-08. L70rnexpressed in hours is the time the Lighting delivers 70 % of its initial flux. We acquire the Lifetime usingrnThe Exponential degradation model. The lifetimes of LED Flat Lighting are around 11000 to 28000rnhours. We analyze the cost results for the LED Flat Lighting against the baseline of conventional fluore-rnscent lighting. Costs shown reflect use for a total eight lighting in the space (equivalent amount of interiorrnLighting). None of the LED Flat Lightings tested is a more cost-effective alternative than conventionalrnfluorescent Lighting. Simple paybacks for the LED Flat Lightings are either never reached or are high.rnSimple Paybacks for the LED Flat Lightings ranged from 12 years to 13 years. Initial optical perfo rmancern(March 2010) of LED Flat Lighting was compared with respect to optical performance of 6000 Operatingrnhours later (December 2011). Both total luminous flux and luminous efficacy, they was decreased fromrn12,0 % to 6,0 %. For LED Lightings, Main parameters affecting the luminous flux depreciation is therndriving current, the ambient temperature, moisture environment, but also atmospheric pollution. Bothrncorrelated colour temperature and general colour rendering, they was increased from 1,0 % to 6,0 %rndue to several reasons. We observed significant shift of colour coordinates towards cooler white. It isrnusually not possible. In this paper, this phe nomenon is interesting for LED Flat Lighting.Conclusions:rnThe results of this paper showed that the lifetimes of LED Flat Lighting are around 11000 to 28000 hours. None of the LED Flat Lighting tested is a more cost effective than conventional fluorescent Lighting. Simple payback for the LED Flat Lighting is never reached compared to conventional lighting baseline. Initial optical property of LED Flat Lighting was compared with respect to optical performance of 6000 operating hours later. The Result showed that optical performance of LED Flat Lighting changed during 6000 hours later due to simplified considerations stated above. However, LED Flat Lighting still a relative new solution in the general lighting and can compete with a longstanding technology to their high performance.