Effect of adaptive control on the LED street luminaire lifetime and on the lifecycle costs of a lighting installation

Abstract

We report for the first time the effect of ageing due to adaptive control of lighting on the lifecycle costs of luminaire installations. Two types of LED street luminaire were aged (1) as the luminaire lit for 9 hours and then switched off for 3 hours and (2) under intensive ageing using adaptive control conditions mimicking presence of vehicles, where the luminaires were switched with 30-second interval between 100% and 20% power within the cycle of (1). The test continued for 32,000 hours. Luminaire lifetime was found to decrease by 10% due to the intensive adaptive control, which exaggerates the ageing as compared to real traffic conditions. We estimate that a realistic rate of dimming cycles would decrease the luminaire lifetime by 0–2%, increasing the lifecycle costs of a lighting installation by 0–0.7%. With a traffic-aware control system, capable of 50% energy saving in lighting, the lifecycle costs are estimated to reduce by 25% as compared to a similar LED luminaire installation without traffic-aware control, outweighing the costs due to the reduced lifetime. The smart controlling of lighting is considered as a useful way to meet future energy saving targets.

Recent advances and perspectives in photometry in the era of LED lighting

“…The LED lamps are quite resistant to frequent switching, ensuring consistent performance and reliability over time. In fact, the first definite observation of reduced lifetime due to switching was observed only recently in natural ageing conditions [58].…”

“…Significant energy and cost savings can be obtained with LED lighting when light is used only when needed in buildings, pedestrian areas, and streets [59][60][61]. Figure 4 shows a comparison of streetlamp ageing results, when one lamp group has natural ageing while another cycled group of lamps has been switched between 20% and 100% power with 30 s interval [58]. Although after 10 000 h of ageing the cycled group shows a few percent lower luminous flux, the switching frequency is about ten times the average switching frequency which would occur in real traffic conditions with smart lighting.…”

“…Although after 10 000 h of ageing the cycled group shows a few percent lower luminous flux, the switching frequency is about ten times the average switching frequency which would occur in real traffic conditions with smart lighting. Thus, the effect of smart control in energy savings exceeds the increase of maintenance costs due to the decreased lifetime of switched streetlamps [58].…”

“…Figure 4. Effect of 30 s cycling between 20% and 100% power on LED streetlamp ageing[58]. Reproduced from[58].…”

Machine Learning Methods in Smart Lighting Toward Achieving User Comfort: A Survey

“…LED lighting already brings significant efficiency improvements over conventional lighting without intelligence and computing. Askola et al [88] revealed that LED lighting had become an essential driver in the industry in recent years. There is a massive potential for savings when replacing conventional exterior lights with LED lights.…”