The E-lamp: good news?
The E-lamp: good news?
The "E-lamp" was introduced as the light source that would eventually replace CFLs. But it remains to be seen whether the lamp really is an efficient and economical alternative to CFLs.
During the first week in June 1992, nearly every news outlet in the United States reported the unveiling of the "electronic light bulb", also known as the "E-lamp". Behind this marketing coup was the US-based Intersource Technologies, which promised that the E-lamp (or "induction lamp") would be remarkably long-lived, highly efficient, and similar in size to an incandescent bulb. The technology uses high-frequency radio waves to generate light in a manner similar to that of fluorescent lamps, but requiring no filaments (see figure).
However, some scientists have questioned Intersource's claims of efficacy, longevity, freedom from interference with communications systems, and cost. While some of the company's publicity is based on measured data from prototypes, the lamp is still under development. Claims cannot be substantiated until prototype models are independently tested.
LAMP PERFORMANCE
Intersource plans to market its product in 1993. Initially, E-lamps will replace 75-watt incandescent reflector lamps as spot or flood lights in recessed fixtures. A replacement for the 75-watt standard pear-shaped incandescnet will follow. The first batch of E-lamps will be sold to US utilities who will market or distribute them to customers. The E-lamp's makers predict that its price will be comparable to that of its closest competitor, the compact fluorescent lamp (CFL), but that it will last twice as long, fit in more locations, and be available in higher wattages such as a 150-watt equivalent.
Initial press coverage echoed Intersource's claim of an efficacy of 65 lumens per watt, similar to that of a good CFL. But this refers to the lamp efficacy, the reported system efficacy, which includes oscillator losses, is 50 lumens per watt. Recent compact fluorescent models with electronic ballasts achieve up to 70 lumens per watt system efficacy.
The E-lamp's predicted performance rests heavily on the accuracy of the estimated production cost and the lifetime of both the lamp phosphors and the power supply. Intersource states that the lamp could last almost indefinitely, and the power supply components could last over 40 000 hours. However, depreciation of the phosphors would reduce light output by 30% within 15 to 20 000 hours, at which time people typically would replace the lamp. (A CFL, on the other hand, will have depreciated about 20% by the time its filaments burn out after 9-10 000 hours.)
INTERFERENCE AND SHIELDING
Electromagnetic and radio interference pose another potential problem. The E-lamp's operating frequency (13.5 megahertz) and its first two harmonics fall into the Industrial/Medical/Scientific band, in which the US Federal Communication Commission (FCC) allows unlimited electromagnetic signals. Yet, the lamp must be shielded to prevent interference from the third through fifth harmonics. The reflector lamp version uses a cast magnesium housing for shielding, limiting its use in smaller recessed fixtures. The shielding for the standard lamp designed into the lamp wall itself, and the shielding material has yet to be chosen from experimental prototypes. At the end of June, a US independent testing laboratory certified the compliance of a prototype of the standard model with FCC standards.
CONSUMER BARRIERS
The barriers to consumer acceptance of the E-lamp will be similar to the barriers facing the CFL. One of these has been its high purchase price compared with an incandescent. Even if the E-lamp sells at the estimated price of US$ 20 its proponents will have to overcome consumer reluctance to spend that amount for a light bulb.
Recent market reserarch by Intersource demonstrated that the E-lamp would be competitive with electronically-ballasted CFLs. Consumers have also complained that CFLs come in odd sizes and shapes, cannot replace higher-wattage incandescents, and cannot be dimmed. Several manufacturers recently introduced dimmable models, but they are not screw-in retrofits. The first generation of E-lamps will not be dimmable, but later versions will.
Is the E-lamp really new? Major lamp manufacturers have done research on the technology, though none has pioneered it for the residential market. Philips Lighting unveiled its "QL-lamp", an induction lamp with similar technology aimed at the commercial and industrial market, with similar fanfare at the prestigious European Hannover Fair last year (see IAEEL Newsletter 1/92). This product features a higher system efficacy, wattage, life-time, and price tag than the E-lamp.
The E-lamp has made its bid to become the "Compact Disc" of residential lighting, but events during the next year may determine whether it will become a household word.
Barbara Atkinson
Ms Barbara Atkinson is a Principal Research Associate at Lawrence Berkeley Laboratory, Berkeley, CA, USA, specializing in lighting policy analysis. This article was adapted from a version recently published in Home Energy Magazine.