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Previous Page | Contents | Zoom in | Zoom out | Front Cover | Search Issue | Next PageABE FMaGSAlthough LED lighting products sold inEurope bear the CE label, electrical compliancemust be thoroughly checked beforeinstallation. CE marking is neither a certificationnor a quality mark. It is based ona self-declaration procedure, relying ontests carried out by the manufacturer orthe import company on a limited numberof chosen samples. Numerous low-cost LEDlighting products exhibit very bad power factors,introduce unacceptable harmonic distortionsin the mains current, and generatehigh level of electromagnetic fields.As the American program CALiPERrevealed, specifications given by somemanufacturers are often misleading, especiallywhen dealing with LED substitutionlamps (designed to replace incandescentor fluorescent lamps). Anyone responsiblefor prescribing LED solutions in a buildingproject should first send the productsto an independent laboratory for objectivemeasurements.Research carried out in CITADELThe objective of CITADEL is to promote theoptimal integration of LEDs in buildingsthrough research, with a view of supplyingcrucial information to all those concerned bylighting. The goal is to fully characterize LEDlighting products, keeping in mind the specificneeds of buildings and their occupants.Research is necessary to provide unambiguouscharacterization techniques (optical,thermal and electrical metrology traceableto national standards). At the moment,there is a lack in Europe in the field of normalizationrelated to the measurement ofLED luminaries. (In the US, IESNA has providedLM-79 and LM-80 standards that specificallyconcern LED lighting products.)Research is also important in order todetermine the complete set of relevant performancecriteria (quality of light, visualcomfort, electrical parameters, energy-efficiency,and thermal aspects) in buildings.The degradation of these criteria will givethe true value of the lifetime of LED lightingproducts. This very important aspect will beinvestigated by defining the most appropriateaging methods, using climatic testing(accelerated aging) and endurance testing(ON-OFF cycles, voltage variations, etc).The optical and electrical measurementmethods will be devised in such a way asto supply results that present the true performanceof LEDs at their real workingtemperature. Aging procedures will thenbe developed depending on the usage frequencyof the products and the environmentalfactors which act upon them. Applyingthese procedures will enable us to analyzeand identify, while adhering to a rigorousmethodology, the diverse physical mechanismsof the LED breakdown. These stepsof physical experimentation will allow usto determine and optimize the life expectancyof LED products and establish thetotal lighting cost. The CITADEL projectwill also involve analysis of LED productlife cycle in order to ascertain their environmentalimpact during manufacturing,use and end-of-life.Primary goals of the CITADEL program• Identify the requirements and constraintsleading to a successful integration of LEDlighting product in buildings.• Compare existing and recently proposedindices for describing quality of light (e.g.color rendering index) and visual comfort(e.g. UGR or unified glare ratio). Build newcriteria adapted to LED lighting systems.• Establish reliable methods for physicalcharacterization of LEDs and LED-basedluminaries (optical, thermal, electricalaspects).• Determine accelerated aging protocols (climaticand endurance testing) based on reallifeusage and solicitations met in buildingapplications (indoor and outdoor).• Better understand the degradation andbreakdown phenomena observed in thecourse of the product lifetime.• Determine effective life expectancy ofcomplete LED lighting systems based ona multi-criteria risk analysis.• Provide tools for estimating total cost ofLED lighting solutions.• Perform life-cycle analysis of a limitednumber of well-known, commerciallyavailableLED lighting systems.The research carried out in the CITA-DEL project will help French laboratories toqualify commercially available LED lightingproducts. A certification and labeling activitywill be created during the course of theresearch program._____________________LEDsmagazine.com APRIL 2009 13Previous Page | Contents | Zoom in | Zoom out | Front Cover | Search Issue | Next PageABE FMaGS