- Opportunities and challenges
Solid-state lighting (SSL) is expected to considerably reduce lighting energy consumption and drastically lower greenhouse-gas emissions. By 2030, the U.S. Department of Energy (DOE) estimates that SSL has the potential of achieving a reduction of national electricity consumption (from lighting) by 50%; however, several hurdles remain before this can happen. While SSL products hold a competitive edge in many utilizations (retail, household consumptions, street lighting, etc.), this new technology is still at its early stages of development and it will take some time before its full potentials are fully realized. Continued research and development (R&D) have yet to pave the road to the full realization of this technology’s full potential, including in the areas of improved efficacy, quality of lighting and of course cost reduction.
- Lessons Learned to Date:
While R&D has so far demonstrated promising results in cost, color performance, light output, reliability, efficacy and manufacturability of SSL products, SSL technology, similar to any new technological developments, must be allowed to take its ‘natural course’ in order to provide the value for money (vfm) element buyers are always looking for and before these buyers ‘agree’ to begin replacing incumbent lighting options.
Specifically, the dollar cost per kilolumen ($/klm) has been decreasing steadily since 2005 at a rate of about 20% per annum. This has resulted in some LED products achieving a level of competitiveness with their traditional counterparts in the market for some applications.
Yet, despite progress made much more work is still needed in the areas of performance improvement and cost reduction.
A. The latest on LED system performance in high temperature environment: U.S. Department of Energy (DoE) findings
The U.S. Department of Energy has released a report on LED system performance at the Yuma (Arizona) Sector Border Patrol Area. Six LED luminaires- installed on three poles as part of a trial installation detailed in a prior GATEWAY report- continue to be monitored, with illuminance measurements recorded initially in February 2014 and again in September 2014 at about 2500 hours of operation and in March 2015 at about 5000 hours of operation.
Among the findings, measured data at the project site after nominally 2500 hours and 5000 hours indicate that the illuminances are changing more rapidly than anticipated. The distribution of illuminance also changed, with values nearest to the pole increasing while the values decreased farther away from the pole, and the greatest decreases were at the points farthest from the pole.
The DoE report noted the following:
- The uniqueness of the application in the Gateway report, but suggests that many similar applications exist including lighting of correctional facilities, military bases, and even roadways.
- The trial was intended to evaluate both light quality in the application and the potential for savings.
- The DoE sought to evaluate the lighting in the harsh desert environment where during parts of the year temperatures exceed 100°F even at sunset.
- The heat complicates the challenge of a thermal design in eliminating heat from the LED luminaires and ultimately the semiconductor junction to ensure long-term reliable operation.
- The border application calls for high light levels to national security needs and provide reliable operation every night. The trial sought to ensure that LEDs could match the legacy system, but in reality the area in which the LED-based poles are located revealed superior lighting.
- The poles were located between primary and secondary border fences and illuminate the area between the fences. The gap measures 125 ft with the lighting located 45 ft from the primary fence. Poles were spaced at 180 ft.
The topology of the project means that each luminaire, of a pair mounted on each pole, must cover 11,250 ft2 with an average illuminance of 25 lx (or disambiguation). The project design revealed that Eaton’s Cooper Lighting LED luminaires could handle the task when mounted at 40 ft. The QMH lighting is mounted at 64 ft. The superior beam control of the LED luminaires enabled the lower mounting heights.
The report perhaps reveals interesting possible local applications in Qatar and the larger GCC climate with similar (or even higher) summer temperature.
This report was written by Albayan LED Lighting Technologies Head of Marketing, Hashem Awnallah. Albayan is a Qatari company that manufactures and markets a rich list of LED lighting product in Qatar and the GCC region. The author can be reached at firstname.lastname@example.org.