As the first major advance in electric lighting, the incandescent light bulb made its appearance in the early 1900s. With the ability to be produced inexpensively for a wide range of voltages, incandescents work via an electric current that passes through a thin filament of tungsten wire, heating it and causing it to release light. This creation brought about changes in commercial buildings in every possible way. However, as technology and demand have progressed throughout the past 100 years, these once-remarkable bulbs are now being replaced by fluorescents, HID lamps, LEDs, etc.
Introduced for commercial applications in the late 1930s, fluorescent lamps were the next big breakthrough. These lamps require ballasts to regulate the flow of power. Much more efficient than incandescent light bulbs, fluorescents last anywhere from 20- to 30-times longer than equivalent incandescent lamps. “Fluorescent and HID lamps are basically the present-day commercial standard to light large spaces, and there’s a reason for that,” says Bill Alling, president and CEO at Sparks, NV-based Lumenergi. “Some HID sources are very, very efficient (120 or 130 lumens per watt). If we were to replace all fluorescent and HID lamps with incandescent, at 8 or 10 or 15 lumens per watt, you can imagine the number of new power plants and the sheer number of fixtures that would be required to get the same illumination levels that we enjoy today.”
In the wake of the 1970s energy crisis, the need for energy-efficient lighting products expanded and resulted in several new developments. One of those (which is still being improved upon today) is the compact fluorescent lamp (CFL). These lamps can be used in regular light-bulb sockets (with a built-in ballast) and represent one of the most efficient ways to light a facility today.
Next on the scene were high-pressure sodium (HPS) lamps (a type of HID lamp), which produce a continuous (but narrow) spectrum of light. First emerging in the 1960s, HPS and other HID lamps have improved since then via clear ceramic tubes and “unsaturated” lamps.
LEDs followed about 30 years later, becoming widely available for specialized applications in the early 1990s (nearly 90 years after the incandescent light bulb). Although they’re still not widely used in the commercial environment, the reality of that possibility grows each year. LEDs are extremely durable and have a long lifespan. They fail by dimming over time rather than burning out suddenly, and light up about 10-times quicker than an HID or fluorescent lamp. “LEDs [have] a lot of potential,” says Alling. “The technology’s not quite there yet in terms of commercial application; once it is, it will be as exciting as the fluorescent lamp was in the 1940s. You’re looking at 50,000- or 100,000-hour life for an LED vs. perhaps 10,000 or 15,000 hours for a fluorescent.” As white LEDs advance and become more affordable, facilities professionals will reap the benefits of this development via energy savings and reduced maintenance costs.
Alling cites the advent of the electronic ballast (particularly the dimming electronic ballast) as the next crucial step in the lighting industry’s progress. “Right now, dimming electronic ballasts occupy only 2 percent of the market because they’re very expensive (8- to 10-times more expensive than a non-dimming ballast). But, that is changing.”
In the not-too-distant future, efficient and flexible components, the ability to control lighting (including daylighting), and the ability to shed electrical loads will be industry-changing factors. “The siting of new power plants has been a key issue in California. California’s Title 24 requires exploring alternative options before building new power plants. It wants to build new power plants only after the alternatives have been fully explored,” says Alling. Part of that strategy includes peak-demand management: He indicates that when you examine energy peaks over the span of 1 year (8,760 hours), you find that about 40 percent or more of peak usage during the course of a year happens over a period of 80 hours. “If you can match the demand with capacity during those 80 hours, it’s the equivalent of 15-percent more electrical generating capacity.” He anticipates that aggregating buildings to mine excess energy use, and using that to mitigate the peak demand, will be crucial.
Leah B. Garris (firstname.lastname@example.org) is senior associate editor at Buildings magazine.