Lighting Retrofits: Control Strategies
September 16, 2009
This is Chris Matt, Managing Editor of Print & E-Media, with Maintenance Solutions magazine. Today’s tip is improving energy efficiency with lighting controls.
One way to reduce the cost of operating an older lighting system is to replace it with a newer, more-efficient system. Another way is to upgrade existing, obsolete lighting systems with energy-efficient lamps, ballasts, fixtures and controls.
To help meet ASHRAE 90.1-2001, managers must follow three conditions:
First, mandatory controls. Mandatory controls and circuiting provisions in standard 90.1-2001 only apply when the code itself applies. In an existing building, the lighting-controls portion of the standard applies only if technicians replace the existing controls and at least 50 percent of the fixtures.
Next is bi-level switching. This control strategy often is considered a simple, economical way to produce energy savings, but it can be difficult to apply to existing buildings. NEMA defines bi-level switching as a manual or automatic control, or a combination of the two, that provides at least two levels of lighting power in a space, not including turning lights off.
Finally, minimum light levels. While providing at least the light levels recommended by the Illuminating Engineering Society is important, managers also must consider light quality. To achieve acceptable quality, managers must consider visual comfort, glare, uniformity, color rendering, lighting on walls and ceilings, and harsh patterns, shadows, and flicker.
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