Re: What technology will replace LED's as most efficient light source
Efficiency and heat are intertwined. This is why efficiency really needs to be bought up to at least 150 lm/W in order to get the waste heat from a 150 watt incandescent replacement manageable.Originally Posted by beerwax
Remote phosphor is the answer here. You put the blue LEDs inside the globe, coat the globe with phosphor, and you have diffused light without a heavy efficiency penalty.today i am thinking the aesthetics are the achillies heel. an intense point source lends itself to torches, not general lighting. so there will always be unit cost and efficiency loss associated with softening that intensity.
this is where oleds or some of the other technology has a chance.
The reason why LEDs are being pushed, besides the mercury issue of CFLs, is because we're nearing capacity of our grid/generating capacity. It's far easier to replace inefficient lighting than to beef up the grid, or even worse, build new power plants. I'm not really sure incans would have dominated forever even in the absense of this factor. The unit cost is low, but try brightly lighting, say, a kitchen with incans. You're talking 500 to 1000 watts, compared to something like 4 32 watt linear tubes. That translates into an enormous expense in electricity, plus added air conditioning bills. Besides that, let's say you have 10 bulbs with an average life of 1000 hours. On average then you'll have one lamp burning out every 100 hours. If you run the lights in the kitchen 6 hours a day, you're replacing one lamp about every 2 weeks. This is a royal PITA. On the flip side, I put new tubes in the 4x32W fixture in the kitchen in 2001. I finally changed them out last year. 3 of the 4 were still lighting, so I kept them for utility duty since I wanted to start off with all new fresh tubes. I'm home all the time. The kitchen light is on at least 10 hours most days. I hate to think how many incandescents I would have went through in that time, not to mention the cost of the electricity. Same thing with my workshop. Another reason I went to linear tubes 25 years ago over incandescents was to have a more natural, closer to sunlight, color temperature. I'm sure I'm not the only one who feels this way. No, as flourescent and later LED technology improved, it was inevitable it would eventually go from commercial to home use. Remember that industry largely abandoned incandescents after WWII, long before any energy or grid crisis. There were many compelling reasons, most of which are somewhat applicable to residential lighting as well.there are political forces at play too. it is not totally wacko to believe that , given their negligable unit cost , incans would have dominated forever. but politics has been applied. if led unit costs can match or get close to cfl then politics can play the mercury card and cfl is gone.
for general lighting, running costs are not everything. anything that has cfl or better efficiency is probably good enough . certainly once you are little bit better than cfl natural limits mean you cant suddenly make something that uses less than half the power.
In theory some new battery technology can charge in 5 minutes. In practice as range increases the need for fast charging becomes less and less. If your vehicle has a range of 150 miles, and the longest trip you make 99% of the time is 100 miles (this matches the driving patterns of nearly everyone), then overnight home charging is sufficient. We can probably do 300+ miles at this point, effectively making the fast recharge issue moot. Nevertheless, we are working on charging stations where you can charge in 30 minutes, about the same amount of time you might spend at a once every few hours rest stop. Anyway, there's a great thread on EVs over at CPF Green. No need to discuss them further here.edit : have i missed something with electric cars . is there a way to charge them in under 5 minutes ?
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