SpacemanSpiff

A switch mode power supply can do a whole lot more than act as a rectifier. "Switch mode" refers to the turning on and off of numerous silicon switches usually connected to some kind of LC energy storage/filter, and this is the basis of modern rectifiers, inverters, step-up and step-down converters, etc.

It is in fact possible to use a switching circuit to convert an arbitrary ac voltage/frequency to another arbitrary ac voltage/frequency directly without a DC link intermediary. This is called a "matrix converter." http://en.wikipedia.org/wiki/AC/AC_converter

So it should theoretically be possible to take say 200VAC at 400 Hz and convert this to 120VAC 60Hz. In fact this would probably be more compact/less expensive than the usual inverters mentioned in this article, since these are usually meant to be powered by a low voltage DC source and thus have to deal with taking a low voltage and very high current and first stepping this up to several hundred volts, then modulate it into an AC sine wave. A matrix converter (or even AC-DC-AC converter) would have no such requirement if it were powered from the already high voltage aircraft power bus.

At this point I think it's a matter of the technology catching up, since this is a highly specialized application that has just recently become an opportunity for innovation.

EDIT: Also - 240W per person? This seems outrageously high as a baseline load. I would estimate more like 50-100W per person on average, with 300W peak (like when the power supply is first plugged in.) The peak loads would not all happen at once unless everyone decides to plug in and turn on their computers at once, in which case the power limiting would kick in...

2000kCal = 2.3kWh Assuming 5% conversion efficiency (http://en.wikipedia.org/wiki/Photosynthetic_efficiency) Win = 46.5kWh. "standard" solar radiation equals approximately 1kW/m^2, so given 12 hours of solar exposure per day this works out to about 3.9 square meters.

Whenever I do these kinds of calculations I'm always amazed at how much power the sun is able to provide on a square meter 93E6 miles away!

Google maps link: http://maps.google.com/maps?f=q&source=s_q&hl=en&...

Reminds me of this lovely movie: http://www.youtube.com/watch?v=MDqUKj1GwJY&feature=relat...

Makes me miss living in Berlin!

This reminds me of trying to cook pancakes in a microwave back in the day. I poured a shallow plate full of batter and popped it in. This particular microwave had a rotating deck inside, but since the interior dimensions were so small I ended up putting the plate nearly on the center of said deck. Turns out the pancake "cooked" in concentric rings of alternating fluffy goodness and raw batter. Could probably have determined the speed of light using those too..

At this point, they seem to be raising about $50/min through kickstarter. I'd say there is interest in this idea..

WARNING: This discovery cost me about 3 days of productivity a couple of years ago ;)

Agreed. Their CEO Nathan Seidle gave a talk in one of my classes at CU and seems like a great guy. We also took a tour of Sparkfun and their facility is really amazing. They have a great selection of parts/gadgets available for "hardware hackers".

love it. Was just getting ready to post this myself.

anyone know the origin of that photo? I'm surprised there's not a parody on that one.

some great blackbird info on this site, including the flight manual! http://www.sr-71.org/blackbird/

Looks like the levels and perhaps the idea are based on "Super Pixel Bros" game: http://hackaday.com/2010/02/19/update-most-interesting-game-... Here's a youtube progress update: http://www.youtube.com/watch?v=Avvba3prLlc

Pretty awesome if you ask me.

I wouldn't call Apple's process of developing the iphone and ipad "starting over" software wise though. As far as I know, the OS of both of these devices is based on OS X which of course can be traced back to Nextstep. I believe Microsoft did exactly the same thing with win NT; I've seen "embedded" systems running it. I would say what held back Microsoft's mobile devices in the past was UI and usability, which Apple seems to have well under control.

I thought the same thing but then I read the marco.org article and realized that it wasn't a response to the This Week in Batteries blog, but to an unrelated article that seems to recommend full cycling the battery. I believe what was meant by the marco.org article is that regular full cycling is a lot worse for your battery than simply leaving it plugged in.

The This Week in Batteries blog recommends extending the life of your battery by not constantly leaving it topped off at 4.x volts per cell (which causes the internal aging process to accelerate)

So in essence, they're probably both right. When people ask me what's best for their laptop battery I say charge it to 65% and put it in the refrigerator. Not so great for using your laptop however.

The points you make are good, and I agree with what you are saying. My point was that from an environmental perspective, this device is basically on par with available power generation in terms of efficiency, and when used with natural gas simply moves the co2 generation from a centralized location to many distributed locations, but doesn't cut it down significantly per unit energy produced.

IF the device were to be used with biomass fuel, it would certainly be a huge step forward environmentally, but I don't see where the incentive would be outside of environmental stewardship, which some companies value but many do not. From your reply: "...which means it could be used to store PV energy collected during the day and reuse it at night. But, this system produces so much more energy than a PV cell that I'm not sure it would be of much use." This is exactly why I wouldn't call it a game changer from an environmental standpoint. Basically we're still stuck with the fact that it's much easier to produce power by burning, oxidizing in a fuel cell, etc. than by using solar, wind etc. In my book a game changer would be a technology that enables a move to truly renewable power generation while remaining practical and cost effective. Could the energy server fit that description? Perhaps, but it depends highly upon how it is operated.

That's exactly my point. The process of growing the trees that produce the charcoal should remove as much co2 as is released when the charcoal is burned, thus a closed system.

So forgive me if this sounds jaded, but I fail to see how this technology is a "game changer."

1. Based on the EIA Annual Energy Review 2001 transmission losses only account for 3.1% of total power generation in the U.S.

2. A modern, large gas combined-cycle power plant has a quoted efficiency of over 60% http://www.energy.siemens.com/hq/en/power-generation/power-p...

3. From the presentation: "The carbon footprint is 50% cleaner than the grid and 100% renewable" Wait a minute, if the power generation is truly renewable, then how can it have a carbon footprint at all (other than manufacture etc.)? Isn't the whole point of renewable energy to have a perpetually renewing "closed system"? By that definition then the carbon footprint would be tiny compared to the grid.

The reason they say 50% is probably because they are thinking most people will run the units from gas, but that's definitely not renewable. Also, I can't imagine the efficiency of the unit is much higher than 50-60%, but maybe there's some data on that which I have missed.

4. "They have created 11,000,000 kilowatts so far" How much of this is from the burning of fossil fuels versus renewable fuel sources?

I am all for fuels cells and development of renewable energy. I think what would truly be a "game changer" is if this device could be used to store the cyclical output from a local renewable energy power system - for example store the energy created during the day from a PV installation for use at night. In my opinion this is more "green washing" than green.

edit: formatting

Interesting. Thanks.

Godspeed. Don't know if many readers here are also pilots, but it's always sad to see something like this happen to a fellow aviator. I've flown 310's quite a bit and they can be a handful on a single engine - although I will refrain from speculating about the crash further. Incidentally it's possible to track the investigation using the NTSB website: http://www.ntsb.gov/ntsb/query.asp The accident synopsis will be available online as soon as they update their database. My condolences.

A DC offset would have the negative side effect of causing AC wall transformers to saturate, redering them useless. Also, as far as I know it would cause problems for many kinds of AC motors. True, you could bypass the DC offset with a series capacitor, but then you would suffer efficiency losses in larger appliances, in addition to added cost and complexity. The problem with having +5V centrally regulated and then distributed throughout the house is wiring resistance losses. Let's say you decide to use 16AWG wire, and have a run of 100' to a hypothetical outlet (not uncommon in even a mid sized house). that means your round trip length is 200'. Given the resistivity of copper, the resistance of such a wire is 1.26Ω, and with .5A of current your voltage drop would be .63V. Therefore, 5V would leave the distribution box, and only 4.37V would be available at the outlet. Worse, Pin=5V.5A=2.5W, Pout=4.37V.5A=2.19W. Efficiency of just the transmission system is 87%. You can get a good power factor corrected switching converter that can do better than this just plugging into the standard wall outlet.