OT: Battery backup

[Brian K. White]

On 2/27/2011 11:33 AM, Jay Ashworth wrote:
> ----- Original Message -----
>> From: "Brian K. White"<brian at aljex.com>
>
>> On 2/25/2011 5:21 PM, C Day wrote:
>>> Does anyone use natural gas powered, automatic start-up, stand-by
>>> generator rather than gasoline powered?
>>
>> We do.
>>
>> No worries about running out, indefinite run-tim, no worries about
>> gellied gas or varnished carbuerators surprising you when you need the
>> thing to "just work" "RIGHT NOW". It has an automatic timer that runs
>> it for 15 minutes or so once a week.
>>
>> It's done it's job perfectly several times too.
>>
>> It is of course reliant on the gas line.
>
> Could you not put a check-valved accumulator tank in front of it, whereby
> some sizable amount of pipe gas came in, and could only get out into the
> genset...
>
> and if the pipe supply was shut off, it would still sit in there, waiting
> for the generator to draw it?
>
> I live in a tank-propane area, so those are the terms I think in.

Theoretically but not practically.
It's delivered in gas form at less than 1/4 psi.

At that pressure nothing would accumulate without a compressor, and even 
if you did something like that, the gas does not comress very 
efficiently. Propane can be compressed all the way down to liquid and 
held there without cooling at only a couple hundred psi. So, the 
compressor isn't exotic nor is the tank.

CNG is up to 3,500 psi and still a gas. Tanks that can hold that 
pressure safely and regulators that can dispense it back out at 1/4 psi 
safely are reasonably available since cng vehicles have been around a 
while, which also means the energy density must be enough to run at 
least a little while even though still just a gas.

If Honda hadn't killed FuelMaker you could get a home CNG pump. With 
that pump you could use all off the shelf (if still rather uncommon and 
pricey) cng vehicle parts to cobble something together and even have it 
be reasonably safe. But they did and you can't.

-- 
bkw