Dimming doesn’t mean darker

Dimming doesn’t mean darker

Dimming helps maintain brightness and save energy in HID lighting

BY RON FLORES
IEPC
Hungtington Beach, CA
http://www.iepc.cc/

As concerns about energy use skyrocket, and with regulations such as California’s Title 24 becoming more widespread, many businesses are looking for ways to cut energy use and energy costs. Unfortunately, many believe the only options include switching from their bright HID lighting systems to fluorescent systems that are more efficient but less bright.

Using new technology and embedded controls can reduce HID lighting fixture counts up to 33%.

Some cut corners by shutting off aisles of lights during the business day to cut usage, but balk at the suggestion of “dimming” their lights. That’s because dimming, in the lighting industry, has always meant turning down the brightness of a lamp and making the space darker. But today, dimming actually translates to maintaining brightness and saving energy.

Solid state lowers energy cost

Using new solid-state technology and its embedded controls, customers can reduce their HID lighting fixture count by 25% to 33%, increasing the performance and optimizing the efficiency of each lamp while lowering lighting energy costs by as much as 40% to 60%.

Traditional magnetic and electronic ballasts are single-output and therefore overdrive most lamps. For example, a generator that produces 227 Vac to power a 400-W light lamp gives a lamp wattage output that’s higher than necessary.

Increased voltage increases the current draw of the lamp, which results in higher energy costs. Using 227 V to power a 400-W lamp will overdrive the lamp, which will degrade at a much faster rate, shortening the life of the lamp.

Power vs. brightness

As the lamp degrades it will need to draw more power to maintain its original brightness, wasting energy. You won’t notice the reduced brightness at first, but eventually the light will start changing color and in time will burn out much faster than if it had been driven by a lower current—resulting in the expense of new lamps and additional labor much sooner and more often.

Traditional ballasts have an inability to respond to on-demand lighting changes and to know when to re-amp, which wastes energy. Also, sometimes lamps are left on to avoid startup time and they draw more power but have reduced output.

As lamps age, they become less bright and burn more energy to maintain the same level of brightness. Users may resist replacing old lamps due to perceived costliness, but the real question is what costs more—replacing old lamps with new or continuing to use old ones that burn more energy to achieve equal or less brightness than when they were new?

Brightness plus energy saving

New lighting technology with embedded controls, however, allows users to save energy without darkening their stores. When installing this technology with a new HID lamp, you can set the output power at 80%, resulting in an immediate 20% energy savings, but with no visible difference in the brightness.

In addition, because less current is being drawn, the lamp degrades at a much slower rate, extending the life of the lamp. Under normal circumstances, in an HID lighting system that is driven by magnetic ballasts and some electronic ballasts, HID lamps will vary in color, one from another, depending on the their age. The inconsistent color affects the overall brightness of the space, causing inconsistent brightness over time.

If you drive a new HID lamp at 80% for the first six months, and then at 90% to maintain the same brightness in the second six months, you are still saving an average of 15% in energy costs in a year without overdriving the lamp, sustaining the same brightness with better energy efficiency.

An added benefit is that by reducing the lighting brightness by 15% on average, the lamps will produce less heat. Because an overdriven lamp is not going to be any brighter than one driven at a lesser current, the excess energy will generate heat. In high-bay lighting facilities, this excess heat will necessitate a more powerful cooling system, which adds to energy use and energy costs.

Dimming doesn’t mean darker. It means consistent brightness, reduced heat output and increased energy efficiency. It also means scene control. One of the greatest wastes of energy is lighting that runs at the same brightness 24 hours a day, whether it’s needed or not. For example, a facility that incorporates skylights in its structure could run its lights at a lower brightness during the day to make use of the natural sunlight. But traditional magnetic and electronic ballasts generally do not allow for this kind of scene control forcing the lights to stay at the same brightness day and night. ■

For more on HID lighting, visit http://electronicproducts-com-develop.go-vip.net/opto.asp.