MEXICOWANDERER wrote:
The high wattage LED fixtures I am building (350 watts) are almost identical in lighting intensity of 400W Metal Halide. But the LED's I construct do not need the lighting focused - they are for general area lighting. The big issue I have found with LED is the absolute necessity to have a heat sink large enough to cool the chips. This is the fox in the hen-house of LED design. Aluminum extrusions are anything but cheap. This forced me the incorporate cooling fans for the smaller heatsinks. What is the definition of "expensive"? A dollar and a quarter 10-watt LED chip versus eight dollars for the heat sink.
hitting nail on the head.
This is still an "unsolved" problem for the lighting industry, especially for space and format constrained applications, like retrofit bulbs for existing residential and commercial fixtures.
Big passive coolers are expensive materials wise, and don't fit into existing fixtures too well. Active cooling, like piezo-electric and electrostatic fans move air across a small heatsink without moving parts but are still prone to getting clogged by pollen, skin dander, cooking oil vapor, etc. Once they are clogged up, the led lamp has to fold back current or maybe just burn out.
The poor LED starts to sweat at a mere 100C and really begins to panic at 150C, temperatures considered cold by other lighting technologies.
