Lighting's Workhorses

Jim Benya looks at the latest in lamps and ballasts

Source: ARCHITECTURAL LIGHTING Magazine
Publication date: 2009-08-01

By James R. Benya

Based on the innovations in lamps and ballasts since our last report (“Lighting's Latest Nuts and Bolts,” March 2008), the economy has not slowed the push to develop new products in these categories. Of course, new LED offerings are being introduced with greater frequency as they become serious product contenders, but there are a bounty of developments in regular lamps that still deserve attention.

The good ol' incandescent lamp is on its last legs. Despite rumors of a high-efficacy version, the only way to significantly improve the efficiency of an incandescent is to use relatively expensive technology such as the halogen cycle (a complex chemical interaction between tungsten, oxygen, and a halide), infrared reflecting coatings, and rare backfill gas. Tungsten may be nearing the end of the line unless a breakthrough is achieved. The worldwide movement to ban the bulb has abated slightly, but don't plan on being able to buy them 10 years from now.

But there are a few applications where tungsten lamps are still king and new products are still emerging. The principal developments are mostly in halogen and halogen IR projector lamps, where reflector design allows lower wattage while maintaining beam candlepower. Across manufacturers, the 45W to 48W PAR30, the 45W to 55W PAR38, and the aluminum-reflector 300W PAR56 and 1000W PAR64 are all examples of meaningful improvements.

While we wait for sound LED options for incandescent replacement lamps, compact fluorescent lamps (CFLs) are still the cost-effective, energy-efficient alternative for many traditional incandescent applications. A steady flow of innovations continues, with new state-of-the-art products including:

• Spring-shaped lamps available in both medium screw and GU24 bases that are dimmable and smaller than ever, allowing more lumens in more places;
• PAR-style, screw-based aluminum reflector lamps suitable for recessed downlight applications;
• GU24 lamps in more sizes, shapes, and wattages; and
• Colored screw-based CFLs for use as party lights, bug lights, black lights, and other playful applications.

Jim Benya diagrams lamp ballast efficacy—the efficiency based on mean lumens per watt—using current market product offerings.

There is a special family of CFL lamps that uses cold cathode technology. Cold cathode is a type of fluorescent lamp with significantly increased lamp life; the lamps are rated at 25,000 hours. Use them when the design requires sources that last longer and can be easily dimmed or frequently switched, such as in flashing and chasing marquees.

Pin-based CFLsystems have not enjoyed nearly as much innovation, since this market is already established. The most important new products appear to be additions to ballast choices, particularly universal voltage dimming types for both analog and digital control systems. Other improvements include some lamps being rated up to 20,000 hours, including some new triple tube products.

Fluorescent lighting is still the most efficient and cost-effective lighting option on the market, and you can bet it will remain this way for a while. As a result, ongoing lamp and ballast improvements have resulted in some important new products.

One trend is lamps with superior life. Most companies offer T8 lamps with a rated life of up to 46,000 hours, equal to or better than the 70 percent lumen maintenance rated life of many LED products. Others have reduced mercury content and/or a number of reduced wattage variations. The most significant new lamp is the reduced wattage T5HO, the latest version needing only 49W to 50W to produce light levels similar to the original 54W lamp. At least one manufacturer now claims their low-mercury T8 lamps need no burn-in time for dimming operation.

Ballasts also continue to evolve and improve. A wide variety of universal voltage ballasts for T5 and T8 lamps are now available, including high-efficiency versions of instant-start and program-start types for one, two, three, and four lamps at high, normal, or low ballast factors. There are high-efficiency ballasts for F86T8HO and other less-popular lamps. A new generation of low-cost, multilevel ballasts use two switches to select off (both switches off), low (one switch off), medium (other switch off), and high (both switches on). Another uses a single switch to toggle between low and high light levels (to meet the EPACT 2005 tax deduction requirement in existing buildings with single switches). Among dimming ballasts, the latest include “high-efficiency” dimming ballasts that save several watts compared to standard dimming ballasts, and dimming ballasts with both “high-light output” and “low-light output” as well as standard versions. DALI and other digital ballast families also now include more lamp types and operate on all voltages.

Now that costs for lamps and exciters are more competitive, there is a minor renaissance in fluorescent induction lamps. Also called electrodeless fluorescent, these lamps use the same principle of mercury discharge and phosphor emission of visible light as other fluorescent lamps, but are excited by radio waves from a transmitter instead of by the electrodes of a ballast. Low-wattage screw-based induction lamps last two to three times longer than regular CFLs, and the higher wattage sources—lamp life of up to 100,000 hours—make these appealing for locations that are hard to maintain. Their primary limitation is large source size, which forces larger luminaires, but nonetheless there are quite a few choices as manufacturers have recently introduced downlights, high-bay area lights, and outdoor luminaires, just to name a few.

Ongoing improvements and product line expansions of ceramic metal halide lamps are probably the most important HID developments. Ranging from 20W MR16 to 400W E28 and E37 lamps, the superior color and high efficacy of ceramic lamps continues to impress. The latest products include compact lamps at 210W and 315W that have high lumen maintenance and dimming, making them ideal for new indoor and exterior luminaires where point sources are needed.

An important innovation is the self-ballasted low-wattage metal halide PAR lamp. These lamps, which fit directly into medium base sockets in tracklighting gear, replace tungsten lamps and can reduce display lighting power by 50 to 67 percent.

Among metal halide ballasts, three major developments stand out:

In another exciting development, plasma HID lamps have been introduced that achieve 20,000 lumens or more from a source that is about the size of a large LED. These are induction lamps that use microwaves to excite metal halide chemicals inside of a compact vessel, with the potential for creating an incredibly small luminaire with superior efficiency. There is also the promise of very low cost. Perhaps this source will become the perfect companion to LED sources when large lumen packages are needed. These sources have already moved into professional video projectors and theatrical lighting, so architectural lighting is imminent. Limitations are similar to other metal halide lamps, such as limited dimming range, warm-up and re-strike time, and minor color issues.

Let's face it, this is where most of R&D funding goes, so it should be no surprise that LED products are now being introduced at about 10 times the rate of all other light sources combined. The promise of solid-state lighting—both LED and OLED—remains outstanding. But with solid-state lighting changing so rapidly, constant attention to new developments is essential. For this reason, a separate LED discussion will appear in the next issue of A|L LED, in conjunction with the Sept./Oct. 2009 issue.

While solid-state systems now add to the lighting designer's choices, developments in conventional lighting are decreasing rapidly. However, solid-state lighting must be carefully evaluated on a case-by-case basis, as the cost per lumen-hour is still three to five times that of fluorescent lighting. In other words, don't throw away those lamp catalogs just yet.