20 lm/W? Not very impressive. They should have used more dice driven at less current and they probably could have gotten 28,000 lumens with less than 700 watts. As idleprocess said, the heatsinking requirements for this are ridiculous. In fact, for an array of this power density and power output I think the only practical solution is liquid cooling. And if the liquid is recirculated instead of just taken from the tap and thrown away you'll need something like an air conditioner heat exchanger for proper cooling. Interesting I suppose if you need a huge amount of light with little heat in a small area, but not of any practical use for most other applications. Yeah, 28,000 lumens is about right for lighting an average-sized room, but it's better if it's distributed evenly across the entire ceiling rather than a near point source.
On the other hand, a bunch of BL-1000 arrays on a 1/4" thick aluminum ceiling (maybe 3 per square foot) would be properly heatsunk and would give well in excess of 32,000 lumens in a 100 ft² room. This might be of some use if you just want to demonstrate lighting a room with LEDs. Or perhaps use liquid cooling and cover the entire ceiling with the arrays. That would be maybe one array per inch² and over 1.5 million total lumens in the same room. Definitely good for a solar simulator. /ubbthreads/images/graemlins/grin.gif
