Plant Services - September 2007 - (Page 59) Performance Lighting Table 1. High-bay lamping comparison chart Watts/ lumens per watt (LPW) 465/ 82.2 465/ 61.9 358/ 87.6 Initial lumens/ mean lumens 50,000/ 45,000 36,000/ 28,800 6@5,000/ 6@4,750 Lamp lumen depreciation (LLD) 0.90 0.8 0.95 Color rendering index (CRI) and correlated color temperature (CCT) 21/2100°K 90/4200°K CRI = 75 to 85 CCT = 4,100, 5,000, 6,500K Lamp / ballast 1-400 W HPS Magnetic 1-400 W PSMH electronic 6 -T5HO (2) electronic Ballast factor (BF) 0.85 1.0 0.74 to 1.1 Maintained lumens @40% life 38,250/ 9,600 hrs 28,800/ 8,000 hrs 31,350@1.1 BF@10,000 hours mobIle Improve workflow when you take your applIcatIons The best method for achieving flexible control is by continuous dimming, which permits lighting to be varied to specific levels. Fluorescent dimming ballasts typically can dim between 100% to 10% output, and T5HO linear lamps can dim as low as 1%. HID continuous dimming ballasts can’t be dimmed much below 50% output. Step-dimming permits lighting levels to be dimmed incrementally, typically at full, 50% and off. Step-dim ballasts are readily available for fluorescent and HID lamps, and control is by means of two switch legs rather than a dimmer. Quality improves efficiency Visually enhanced lighting (VEL) is an innovative way to offset total lighting energy demand. In 2004, the U.S. Department of Energy established a Spectrally Enhanced Lighting Program1 that has funded several building retrofits to study the savings potential of using fluorescent lamps with a higher correlated color temperature (CCT). It showed that lamps with an 82 CRI and 5,000° CCT provide the same perceived brightness at a reduction of 20% to 46% of connected load when compared with standard lamps. This is possible because light at higher CCT is cooler or bluer, and the human eye perceives this as brighter2. In a retrofit setting, substandard illumination levels can be offset by a direct exchange of existing lamps for spectrally-enhanced lamps. Alternatively, energy consumption can be reduced by replacing existing ballasts September 2007 with new electronic low-ballast-factor units while still maintaining perceived brightness. For a retrofit, expect a return of one to four years on the upgrade investment. In new construction, implementing a VEL design can provide additional efficiencies by reducing fixture quantities, power distribution requirements, air-conditioning load and peak demand. Many existing plant environments use high-pressure sodium (HPS) lamp sources for general illumination. HPS lamps are indeed more efficient than their HID and fluorescent counterparts. However, the quality of light is very poor, particularly where work is being performed for extended periods (warehouse shift, for example). The Visual Effective Illuminance (VEI) of fluorescent and pulse-start metal halide lamps is significantly higher than for HPS, which results in HPS being a net efficiency loser. As an example of potential savings, exchanging HPS lamps for T5HO fluorescents can reduce energy consumption while improving the visual environment, even though the lumen output is as much as 18% lower (Table 1). Among the advantages of T5HO high-bay luminaires are improved lumen maintenance, longer lamp life, better color temperature and lighter luminaire weight (20 pounds versus. 50plus pounds). For safety and reduced worker impact, the failure of a single lamp in the luminaire doesn’t result in a total blackout. Also, if power is interrupted or if automatic shutoff controls are in use, the fluorescent lamps www.PLANTSERVICES.com With Syclo’s SMART Suite of mobile products, your team will manage assets more efficiently. • Eliminate delays caused by paperwork backlogs • Minimize foot traffic • Increase time spent on assets • Improve productivity www.syclo.com 59 http://www.syclo.com http://www.PLANTSERVICES.com
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