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Fuel-Cell Backup Power Under Your Desk
An Anonymous Coward writes "Just up this evening on the Coleman Powermate web site: This is the first
commercial fuel cell product that I am aware of. Who wants one under their Christmas tree?" I just wish the fuel wasn't quite so expensive.
It seems not to have a serial or ethernet port.
If you are not having it under your desk but in machine room like they show on one of the pics, you will never know if it's actually in good health.
Also I did not see an indication that it could tell a computer to shutdown before it runs out of fuel.
George
Atari rules... ermm... ruled.
why would it be safe to store hydrogen in my house?
You would be amazed at how safe hydrogen is. When I was working in reseach we had an outside gas bottle room which consisted of rows of bottles plumbed in and gas lines going to the relevent lab. Some of these were hydrogen and it was decided to fit a hydrogen sensor to detect leaks and shut it down automatically when the hydrogen concentation reached about 50% of the lower explosive limit.
Anyway, this was installed and seemed to be working. We then decided to test it by gently cracking open a hydrogen bottle under the sensor (which was on the ceiling) and watching the output. Nothing. We opened it a bit more - still nothing. Finally we opened up full and only then did the sensor start to register (but nowhere near the set point).
What was happening was that because the room was well ventilated, the hydrogen dispersed so quickly that it only just got high enough to show on the detector. Any leak apart from a catastrophic failure would be safe.
Propane, on the other hand, is a floor hugger and does not disperse very well. You also beed a lower concentration of it to go bang. So if this leaks it tends to hang about the cylinder and you quickly have a bomb waiting to go off.
The batteries are there to: (1) provide power for you (and the unit) while you're switching hydrogen canisters, and (2) depending upon the design, to even out the line voltage.
[Lecture Mode On]
There are two basic designs for UPSes: continuous and intermittent.
The UPSes that you buy for SOHO use are intermittent -- line voltage feeds a battery circuit (battery charger + batteries + inverter) and goes to a relay, which switches between the battery circuit and the normal line voltage. When line voltage goes off, the relay switches; when line voltage comes back, the relay switches back. While the relay is switching, there will be a short interruption in power, but most AC equipment can handle the (very short) interruption. This type of UPS will also have surge protectors built in to filter out high voltage and spikes, but can't do a lot for brownouts other than switch to batteries.
Continuous UPSes work differently -- the line voltage is used to charge the batteries, which run the inverter, which provides clean, uninterrupted power. No relays, no interruptions, no worry about power spikes or brownouts. Unfortunately, you're continuously charging and draining the batteries -- which significantly reduces the working life of the batteries. This type of UPS requires hot-swappable batteries, and is generally a lot more expensive to purchase and maintain (which explains the popularity of the intermittent UPSes).
[Lecture Mode Off]
From what I read on the site, the AirGen acts like an intermittent UPS -- when line voltage shuts off, the AirGen switches to generated power, and switches back when line voltage returns. The batteries are probably there just to provide the necessary power to start and maintain the generator, and to provide power while you're switch canisters. The AirGen *could* be a continuous UPS, with the fuel-cells supplementing line voltage for charging the batteries, but I doubt it -- everything they've posted on their site points towards the intermittent UPS design.
We call it art because we have names for the things we understand.
Although the Hindenburg disaster is the posterchild for the flammability and hence perceived danger of Hydrogen, you might want to read ``Hydrogen Didn't Cause Hindenburg Fire''
Doing some basic math, the cost of a fuel comes out to about $416.66 per bottle, unless I am missing something major.
One thing you might be missing is that you are paying for two things with each bottle of fuel: the fuel itself, and the bottle that's holding it.
For example you might pay $416 for a new bottle of fuel, but get a $350 credit when you return the empty one (I couldn't find their actual price for fuel refills, but since they're using a metal-hydride storage technology, the cost of the cylinders will be significant).