A Promising New Technology—ElectroCeramescent Lighting

November 1, 2002



Photo of sign at DOE's National Energy Technology Laboratory that displays a solid-state ceramic light

Solid-state ceramic light using Electro-Ceramescent lighting technology is displayed on a sign at DOE's National Energy Technology Laboratory in Morgantown, West Virginia

Most illuminated commercial signage utilize conventional technologies, such as incandescent or fluorescent lamps, for its illumination. A promising new lighting technology, called ElectroCeramescent (ECer) lamps may lead to dramatic power reduction and improved illumination. Developed by Meadow River Enterprises, Inc., in collaboration with the U.S. Department of Energy, the New York State College of Ceramics at Alfred University, Marshall University, and Osram-Sylvania, ECer lighting reduces the power requirement for typical commercial signs by as much as 90 percent.

The typical efficiency of incandescent and fluorescent lights is 15 and 75 lumens per watt, respectively. While the efficiency of an ECer lamp can be as low as 4 lumens per watt, even a low efficiency ECer lamp uses dramatically less power than conventional light sources for a given task. ECer signage is equally visible at lower overall power consumption, because the source of the light is directly viewed, rather than a reflection. A 4-foot x 14-foot sign using conventional T-12 high output fluorescent lamps would require 550 watts. ECer technology reduces the power demand to less than 12.5 watts by forming letters and symbols with laser-cut ECer lamp panels, thus lighting individual characters rather than the entire sign. Unlike incandescent and fluorescent lamps, the flat and uniformly lit ECer lamp produces virtually no heat, glare, or halo even in adverse weather conditions, so little light is wasted. Reflected light configurations, widely used for illuminated signage, waste much of their energy in heat and by lighting the ground or sky—a significant source of light pollution.

The solution to light pollution lies in quality lighting systems that enhance nighttime ambiance rather than reproducing inappropriate daylight conditions. A powerful design approach is to directly light the surface of objects that need to be visible with minimal use of reflected light, and matching its spectra to human eye sensitivities. Because the required light levels (and power demands) of signage can be remarkably low, surface light sources and associated fixture design are the critical parameters. ECer lighting systems can dramatically reduce unnecessary nighttime illumination, while cutting energy consumption and improving visibility. This produces a better, more visible sign with reduced energy use.

Applications

ECer lighting has inherent mechanical strength because of its ceramic thermal fusion and steel structure. As a result, ECer lamps are well suited for outdoor applications with high environmental stress. Landscape lighting applications (often termed "lightscaping"), including entrance and exit signs, security warnings, building numbers, address markers, and pathway elements like flagstones, step edges, and corner markers, offer substantial market opportunities. Beyond the energy savings, ECer lamps provide aesthetic advantages as well. On walkways, for example, ECer lighting illuminates the path rather than the entire path area. The durability of the ECer ceramic-on-steel technology also permits rough handling and outdoor exposure without damage. Low power levels and long service life provide an attractive life-cycle cost, as well as an ideal lighting platform for usage with a wide range of conventional and alternative energy solutions; including: grid power, solar (photovoltaic), wind, battery, fuel cells, etc.

ECer lighting is also appropriate for many indoor applications for both residential and commercial buildings. Low area lighting levels can be combined with brighter ECer lighting for steps, lighted controls, and signs. Because they are so rugged, ECer lamps are also particularly well suited for locations prone to vandalism.

Costs

The initial cost outlay for ECer signage is comparable to conventionally lit products. With the added advantage that ECer signage can last up to 50,000 (or more) hours with little maintenance, life-cycle costs of ECer signs are significantly reduced. Their long service life reduces costs associated with frequent bulb replacement, an important factor for lighted signs that are difficult and/or costly to access. In applications where remote power is required to illuminate a sign, a solar-powered ECer solution could actually be less costly than conventional lighting alternatives.

There are approximately 19 million electric signs installed in the United States with total power consumption of about 17 billion kilowatthour per year.1 The current operational cost of these signs is approximately $1.7 billion per year. If all these signs used ECer technology, the energy cost could be reduced by at least 90 percent, with savings of approximately $1.5 billion per year or 15.3 billion kilowatthour. Cost savings from reduced energy consumption alone would more than repay the cost of the sign over its expected lifetime. When lower maintenance costs are included, the break-even point for replacing fluorescent and incandescent signs with ECer technology is approximately 5 to 7 years (depending on the labor costs associated with lamp replacement).

Testing

DOE's National Renewable Energy Laboratory has been conducting facility signage and pathway marker lamp testing for 3 years. Complete ECer sign assemblies have successfully completed thermal cycle testing over a temperature range of -20� F to +120� F, as well as simulated rain exposure and total water immersion testing.

Conventionally-powered and solar-powered demonstration signage is currently being tested at four West Virginia State Parks as well as at DOE�s National Energy Technology Laboratory in Morgantown, West Virginia. In a joint effort with the Nick J. Rahall, II Appalachian Transportation Institute and Marshall University, Meadow River Enterprises has developed, and is testing, a pair of "smart" ECer highway signs (designated for use on U.S. Interstate 64 in West Virginia). These informational signs have been designed to automatically respond to inclement weather by dramatically increasing their illumination intensity.


ElectroCeramescent (ECer) lighting is the result of 4 years of research and development completed in November 2001. The project was conducted through a $1.6 million cooperative agreement with the U.S. Department of Energy (DE-FC26-99-FT40631) and Meadow River Enterprises of West Virginia.

Graph showing the basic design of an ECer lamp panel

The figure above illustrates the basic design of an ECer lamp panel. The lamp is comprised of a series of layers on a steel substrate. An electrical potential applied across the electrodes (the steel substrate and the transparent conductive layer) introduces a high voltage field across the phosphor layer, which causes electrons to accelerate to high energies and activate luminescent centers in the phosphor. Light is produced when the centers relax to their ground state. The ECer panel can be driven by an AC power source over a wide range of voltages and frequencies. Transformers and inverters are used to convert the primary power source (e.g., utility, battery, solar) to an appropriate voltage (typically 90 to 250 volts root-mean-square) and frequency (usually 60 to 1,000 hertz) for optimum ECer performance. Typical illumination levels are in the 1- to 10-foot-lamberts range.


For more information regarding ElectroCeramescent (ECer) lighting technology, see the Meadow River Enterprises, Inc. web site at www.area125.com.For additional information, please contact Jim Brodrick of DOE�s Office of Building Technologies at james.brodrick@ee.doe.gov, or Ted Collins of FEMP at theodore.collins@ee.doe.gov.

_________________

1Assuming an average life of 15 years and an average cost of $1,500 per sign, the installed illuminated sign base is on the order of 19 million signs. Assuming an average power consumption of 200 watts per sign for 12 hours per day, 365 days per year, total annual power consumption is approximately 17 billion kilowatthours. Assuming a 2001 energy cost of $.01 per kilowatthour, the current operational cost of these signs (energy component only) is approximately $1.7 billion per year.