Google Offers a Million Bucks For a Better Inverter

An anonymous reader writes: With the Little Box Challenge, Google (and IEEE, and a few other sponsors like Cree and Rohm) is offering a $1 million prize to the team which can "design and build a kW-scale power inverter with the highest power density (at least 50 Watts per cubic inch)." Going from cooler-sized to tablet sized, they say, would make a whole lot of things better, and the prize is reserved for the best performing entrant. "Our testing philosophy is to not look inside the box. You provide us with a box that has 5 wires coming out of it: two DC inputs, two AC outputs and grounding connection and we only monitor what goes into and comes out of those wires, along with the temperature of the outside of your box, over the course of 100 hours of testing. The inverter will be operating in an islanded more—that is, not tied or synced to an external grid. The loads will be dynamically changing throughout the course of the testing, similar to what you may expect to see in a residential setting." The application must be filled out in English, but any serious applicants can sign up "regardless of approach suggested or team background." Registration runs through September.

Comments

"to not look inside the box"

[fche]

An awesome way to smuggle a wifi sniffer - or something naughtier - into the googleplex!

I've heard this one...

[roc97007]

...happened many years ago. The government speced a power supply so clean that it couldn't economically be done at the time. The company that won the contract produced a box that met all the specs. Except that it failed after several hours of use. Opening the box, they found the power cable connected to a strain relief and the main power provided by a lead-acid battery.

Word is, there was no spec for lifecycle so the devices met the contract as stated, and the government couldn't return the devices.

So I'd recommend to Google: At some point, look in the box.

Re:I've heard this one...

[Beck_Neard]

If you've got a battery with that kind of power density, it's actually a formidable explosion hazard. With thirty times the energy density of rocket fuel, even a minor internal short would cause a chain reaction that would make a battery pack the size of a laptop battery explode with the power of over one hundred kilograms of TNT.

Why?

[Obfuscant]

One question: why?

If you're running devices that need a kW you're already at a reasonable size for your device, and you can build a lot of cheap, larger inverters for what it would cost to build this small one.

You could also probably build the powered devices to run off 12V for less than what this inverter would cost.

Is what is keeping AC power from the hinterlands this is intended to serve really the size of the inverter, or is it more likely the cost?

Re:Why?

[viperidaenz]

and this is the reason it is 48V.
Copper is expensive. You don't want your 42U rack, which pulls 8kW powering it's 42 1U servers, drawing upwards of 700A.

For a 1% power loss over 1 metre at 700A, you need 0000AWG cable. It's about 1kg of copper (that's a single conductor, you'd need one for the return path, another kg and another 1% power loss)
But 0000AWG can't actually handle that amount of current without active cooling. for 90C rating, it's only 260A.

700A for 1M distance has cost you 160W of power and 2kg of copper and you need some fancy cable cooling technology.

If you upped the voltage to 48V, you only need 175A.
You'll be fine with 2AWG cable if you can keep it cool and only lose 30W. You could use 0AWG, which would cost you 1kg of copper and only have 19W of wasted power.

Everything but the 40 in^3

[tesla_reincarnated]

The start up I work for practically has this product to a T. The only design spec's we don't match are the 40 in^3 (we are slightly larger, but smaller than a briefcase) and the output voltage (we do 480V 3-phase rather than 240 single). Otherwise (power density, harmonics, ability to handle loads, etc.) we've got covered. This isn't a ploy, but if anyone is interested in what we do (10 person team, solar inverter manufacturer in silicon valley) check out www.HiQSolar.com

Re:110 or 240v

[NotQuiteReal]

Heh, once, in a pinch, I have made due with a "special" extension cord - with two 3 prong 110 heads spliced onto a 220 socket... All I had to do was find two outlets on different phases and I was in business ;-)

Don't worry, I cut it up when I was done.