Guest Post by Jim Brodrick, Department of Energy
[Recently] DOE published the latest round of results for the CALiPER program, which tests a wide range of SSL products that are available on the market. These latest results are highlighted in a Round 10 Summary Report that’s posted online [PDF format], with detailed reports due to come out soon. CALiPER Round 10, which was conducted from October 2009 to February 2010, looked at 28 products in four applications: parking-structure luminaires, outdoor wallpacks, cove lighting, and replacement lamps. For benchmark purposes, similar parking, wallpack, and cove products that used traditional light sources were also tested.
The main focus of Round 10 was on commercial applications where the luminaires were generally larger in size and higher in wattage than those tested in previous CALiPER rounds. So although the average efficacy in Round 10 was about the same as in Round 9, the results were still very encouraging, because they show that solid-state lighting products are now capable of achieving those same efficacy levels in significantly larger, higher-output luminaires, as well as in smaller integral replacement lamps.
Not only that, but Round 10 offers still more evidence that SSL products are becoming competitive with their traditional counterparts in an increasing number of applications. We’re seeing more and more LED lighting products that are able to match or even outperform incumbent benchmarks in light output and efficacy, as well as in light distribution. As Round 10 clearly shows, you can add parking-structure and wallpack fixtures to that growing list. Although there was still a very wide range of performance in SSL products for both applications, many met or exceeded the light output and efficacy levels of the benchmarks, while also displaying more uniform light distribution.
In addition, the SSL products in these categories produced less uplight than their traditional counterparts – which, while not ideal in some parking garages, can be a significant advantage in many outdoor applications, where dark-sky concerns come into play and light-trespass ordinances are often strict. What’s more, the majority of the LED parking-structure and wall-pack products tested in Round 10 met or exceeded their manufacturers’ performance claims, while most of their benchmark counterparts did not. That’s a substantial improvement over what we’d been seeing in previous CALiPER rounds, where half of the LED products were found to have literature that was inaccurate or misleading.
So even though in Round 10 some SSL products at the lower end of the performance spectrum fell short of the mark in terms of uniformity as well as efficacy and output, the overall trend is heartening, because we’re seeing well-designed parking-structure and wallpack luminaires that are as good as, or better than, their metal halide, high-pressure sodium, and induction counterparts.
The key words here are “well-designed.” Some manufacturers are being truly innovative in their approach to optimizing the use of LED technology to get even better light distribution than traditional technologies achieve. In previous CALiPER rounds we saw that trend with some of the smaller products, but now we’re seeing it with full-blown commercial applications as well. The bottom line is that when an SSL product is designed well, it can get very good light distribution in addition to high efficacy and appropriate light output.
So it’s not just a question of light output and efficacy anymore. The potential for better light distribution offers yet another way to save energy with SSL, because better light distribution cuts down on wasted light. On top of that, there’s the issue of controllability – which, in theory, at least, is another area where SSL has an advantage over traditional lighting technologies. LED products can be more easily dimmed and controlled than many conventional light source technologies, and their lifetimes aren’t impacted by frequent on-and-off. So adjusting actual usage to better reflect the application’s needs – for example, with an occupancy sensor – could result in even greater energy savings.
But even though good luminaire design is essential if SSL products are to compete successfully with traditional lighting technologies, not all manufacturers are paying enough attention to it. That appeared to be the case with the LED cove lights that were tested in CALiPER Round 10. While most of them met the light output levels of their benchmark counterparts for decorative applications and achieved significantly higher efficacy than xenon cove lights, they didn’t match the performance of fluorescent cove lights for general lighting purposes.
Why? For one thing, it appeared that the manufacturers didn’t give enough thought to directing the light where it’s supposed to go. As a consequence, their products couldn’t compete against the efficient fluorescent cove lights used for general illumination – although they matched or outperformed the less-efficient xenon, halogen, and incandescent products that are used for decorative applications.
That’s a waste of solid-state lighting’s full potential – kind of like having a baseball pitcher who’s got a 100-mile-an-hour fastball, but who can’t find the plate. Putting more effort into product design will enable “pitchers” like that to sharpen up their aim. That – coupled with the other “players” who are already doing things right – is sure to move the SSL team closer to winning the energy-savings pennant.
