LED-Street-Lighting-East-Hampton-2021-07-13_RPI

LED Street Lighting Maximizing the Benefits Jean Paul Freyssinier Lighting Research Center, Rensselaer Polytechnic Institute Presented to the Town of East Hampton, NY July 13, 2021 Outline • Background • Purpose of street lighting and characteristics • Guidelines for selecting appropriate retrofit lighting • Services offered by this program • Questions and answers Background Background • Benefits • Safety, environment, energy conservation • Uniformity • Technology • Light emitting diodes (LEDs) • Application efficacy • System life Why we light? • Visual performance • Speed and accuracy of high visual acuity tasks • Safety – crash avoidance • • Vehicle-to-vehicle – on-axis judgement Vehicle-to-pedestrian – off-axis detection • Scene brightness • • • Visual comfort Appreciation of the visual environment Circadian entrainment • Security • Quality of life Value – beyond energy savings • Value can be increased by reducing costs, including environmental costs, and/or by increasing benefits to humanity Benefits Value = Costs Lighting affects two systems Amount Spectrum Distribution Timing Duration Visual + non-visual Visual Performance Visual System Appearance Performance Non-Visual Systems Alerting Effects Amount Spectrum Distribution Phase Shift Timing Duration Main properties of electric light sources • • • • • • Light output • Spatial distribution Luminous efficacy (lm/W) Light source color • Color of illumination • Color rendering properties • Color consistency Lamp life • Catastrophic failure • Parametric failure (lumen depreciation) Warm up and restrike time Operating costs Boyce 2014 Boyce 2014 ~200 1800–6500 ~100 10 Comparison among different light sources 12 3:1 10:1 13 Uniformity of illumination • Commonly, LED luminaires are built to match beam distributions of traditional HID luminaires – • To maintain similar light levels and distribution Small source size allows LED luminaires direct light to where it is needed – Highly uniform illuminance on parking lot surface 75% less light needed! Narendran, N., J.P Freyssinier, and Y Zhu 2016 Energy and user acceptability benefits from improved illuminance uniformity of parking lot illumination Lighting Research and Technology, 48(7): 789–809 Sponsor: NYSERDA, ASSIST, GE product donation 14 Purpose and Characteristics of “Good” Street Lighting 15 What Factors Contribute to Good Street Lighting? Street lighting contributes to: • Visibility • Safety Light level   Visual comfort Perceptions of safety • Depends upon specific situation Uniformity • Avoid contrast between light and dark regions of the street and sidewalks 16 What Factors Contribute to Good Street Lighting? Aesthetics and appearance • Luminaires (light fixtures) should fit the character of an area Cost • • Initial (purchasing and installation) Operating (energy and maintenance) 17 What Factors Contribute to Good Street Lighting (cont’d.)? Glare control • Avoid light fixtures that not shield view of the light source • Low mounting heights can be problematic Light pollution control • Sky glow • Light trespass (shielded or properly located) 18 Guidelines for Identifying Appropriate Retrofits 19 LED Streetlights and Application Efficiency • Even when matched for lumen output, LED streetlights produce higher illuminances on the roadway compared to HPS 20 Equivalent LED Lumen Output for Equal Illuminance as HPS • Because LEDs produce more short-wavelength (“blue”) output, LED lumen output can be reduced to achieve equivalent brightness perception – 4000 K CCT: Factor = 1.46, 3000 K CCT: Factor = 1.21 21 LED Lumen Output Ranges for Equivalent Visual Perception • • LED lumen output is used rather than LED wattage because LED luminous efficacies continue to increase Use the lowest lumen output that is at least within the specified range 22 LED Streetlights and Uniformity • In general, LED streetlights produce more uniform illumination than HPS, but when spacing is very long (~300 ft), lighting will always be non-uniform 23 Conclusions and Caveats • Selection of LED luminaires based on the previous table will achieve energy savings of ~70% – Lower illuminances and increased application efficiency of LEDs can lead to corresponding decreases in light pollution and light trespass – Increased application efficiency for roadway illumination could result in proportionally lower light levels on sidewalks, if present – If sidewalk appearance is critical, consider increasing LED lumen output by 10% 24 Services Offered by This Program 25 Technical Assistance is Available NYSERDA offers limited technical assistance to municipalities looking to convert street lighting to LED technology • • • Assistance with product selection Technical analysis of light levels/distributions Evaluation of existing/replacement lighting Contact your Clean Energy Communities coordinator to get started 26 Thank You! Questions & Answers