Panel-Level Dimming
This strategy involves installing a control system at the electric panel to uniformly control all light luminaires on the designated circuits.
You can control circuit dimming, manually or by inputs from occupancy sensors, photosensors, timers, or energy management systems. Panel-level dimming is a method for dimming HID systems as well as both electronically and magnetically ballasted fluorescent systems.
Continuous dimming is accomplished using a variable voltage transformer that reduces the voltage to the HID or fluorescent circuit.
For example, suppose you are using photosensors in a warehouse with skylights. The high-pressure sodium lighting system could be uniformly dimmed in response to the available daylight from the skylights, saving substantial amounts of energy.
Another application would include a wholesale merchandising outlet that requires higher light levels during normal business hours and reduced light levels during routine maintenance and stocking operations. The scheduling control system would automatically adjust the light levels based on the business-operating schedule.
Although slight improvements in efficiency can result from the dimming of fluorescent systems, slight reductions in efficiency result from the dimming of HID systems. Light output reductions are about 1.2 to 1.5 times the power reduction in metal halide systems and about 1.1-1.4 times the power reduction in high-pressure sodium systems. Manufacturers can provide the specific lumen-wattage performance curves for the specific systems being controlled.
Note that some panel-level dimming systems are incompatible with electronic ballasts. Check with the manufacturer to find out if their variable voltage system is compatible with electronic ballasts and whether the system introduces harmonic currents.
Be forewarned that dimming HID lamps below 50% power may result in a significant reduction in lamp life.
You can control circuit dimming, manually or by inputs from occupancy sensors, photosensors, timers, or energy management systems. Panel-level dimming is a method for dimming HID systems as well as both electronically and magnetically ballasted fluorescent systems.
Continuous dimming is accomplished using a variable voltage transformer that reduces the voltage to the HID or fluorescent circuit.
For example, suppose you are using photosensors in a warehouse with skylights. The high-pressure sodium lighting system could be uniformly dimmed in response to the available daylight from the skylights, saving substantial amounts of energy.
Another application would include a wholesale merchandising outlet that requires higher light levels during normal business hours and reduced light levels during routine maintenance and stocking operations. The scheduling control system would automatically adjust the light levels based on the business-operating schedule.
Although slight improvements in efficiency can result from the dimming of fluorescent systems, slight reductions in efficiency result from the dimming of HID systems. Light output reductions are about 1.2 to 1.5 times the power reduction in metal halide systems and about 1.1-1.4 times the power reduction in high-pressure sodium systems. Manufacturers can provide the specific lumen-wattage performance curves for the specific systems being controlled.
Note that some panel-level dimming systems are incompatible with electronic ballasts. Check with the manufacturer to find out if their variable voltage system is compatible with electronic ballasts and whether the system introduces harmonic currents.
Be forewarned that dimming HID lamps below 50% power may result in a significant reduction in lamp life.
Labels: condenser corrosion, continuous lighting, Hal Finkelstein, HID lighting, Panel lighting, photo sensors
posted by Hal at 10:24 AM
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