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This idea answers the question, what happens if you
cross a window-installed air conditioner, with a
portable electric generator?
You get a small portable generator, which you can install
in your window!
I'm writing this idea a few days after hurricane Sandy
passed through, with grid power
still out in my
neighborhood, and power supplied to my house from a
It occurs to me that people who live in apartments
without power have no way of doing something similar,
and thought of this idea as a solution.
Basically, the device consists of a very small generator,
made to mount in the opening of a vertically opened
sash window, just like a portable air conditioner.
Electrical outlets are on the inside, obviously,
eliminating the need for heavy-duty outdoor extension
cords. Intake for combustion comes from outside, and
exhaust from combustion goes to outside.
A lever, or perhaps a thermostat, determines whether
engine cooling is done with air pulled from, and
discarded to, the interior or the exterior of the
building. If you live someplace that's never ever cold,
then you'd get a machine which always uses outside air
and vents to the outside.
To minimize noise, and because a high power density is
valuable in something which will need to be manually
moved around, a Wankel engine would be used.
To maximize safety and cleanliness, the fuel should be
There would be two ways of fueling the generator:
Firstly, on the side of it facing towards the interior of
the building, there'd be a place to screw on a
disposable one pound propane tank.
Secondly, on side of the machine sticking outside the
house, there'd be a refillable propane tank, and a
propane hose and regulator. The hose would need to
be long enough for the tank to rest on the ground, or on
a balcony or fire escape.
The machine would switch between the two fuel
sources automatically, at need, or manually. Whenever
the machine switches automatically from the outside
tank to the inside one, or vice-versa, an alarm would
sound, warning the user that one of the tanks needs to
Obviously, the machine needs to be small and light
enough to mount into a window, but should be big
enough to run a refrigerator, several lights, a radio, and
perhaps a small kitchen appliance (microwave, toaster,
coffeemaker, hotplate, etc.).
It might have an outlet designated as being for the
refrigerator, so it can temporarily turn just that outlet
off, if the fridge plus other things exceeds it's
generating capacity... sort of like a college dorm
Small Wankel Generator
The datasheet says that Clarian's prototype is 10kg including fuel, and produces 5kW. [goldbb, Nov 02 2012]
I don't know if it's baked, but here's a recipe. [Alterother, Nov 02 2012]
||It needs to have a much better seal than most
window units, since even propane exhaust can be
||A propane-fueled engine, directly driving an AC
compressor would actually be quite efficient, you
could take advantage of the cooling effect of the
expanding propane, and skip all those pesky
electricity generation and distribution difficulties.
||Such a device would be great for off-grid areas,
disaster-zones, field hospitals etc. and would have
myriad military uses (would have to use the single
battlefield fuel for that one). It might get a little
over complex when you need balance between
electricity generation and cooling, you'd need at
least one clutch... which could get a bit bulky.
||I had cruised a fair way down your hurricane-inspired idea, wonderin' wot the bluddy 'ell you need AC for, before I realized you meant "alternating current" rather than "air conditioning".
||Bun, though maybe a dry towel would be better. Good luck!
||No, AC means air conditioner, even though there is no air conditioner, and there is alternating current. The fifth paragraph is the key.
||Meche, you are entirely correct... do you think it should
also have some sort of extendable exhaust pipe /
chimney, to help direct gases away from the building?
Which one of you inspired the other to think that I was
writing about an engine powered air conditioner?
Please pretend I wrote "as is," in that paragraph,
instead of the word "like!"
||The goal is to have a window-air-conditioner-sized
device, but it will in fact be a window-mounted-
||No actual air conditioning is involved.
||If, in fact, air conditioning is desired, then we could
have a common window AC installed in one window, and
an instance of this idea, a window AC generator,
installed in another window. If the windows are close
enough together, the AC's AC cord will plug into an AC
outlet on the AC generator, without even needing an AC
||If you have a preference for direct current, instead,
then of course we would modify my idea to become a
window DC generator... and you might cool your
apartment, by plugging into this device, a window DC
||Regardless or disregardless of whether or not the
current is direct or alternating, and, incidentally,
entirely irrelevant to my idea, I generally prefer that
portable air conditioners be electrically driven so that
they can be hermetically sealed, eliminating the loss of
refrigerant... the patent linked to by Alterother has an
engine mechanically coupled to the compressor, which
makes such a seal impossible.
||Shirley you can have the best of both - a hermetically sealed compressor magnetically (rather than electrically or mechanically) coupled to the internal combustion engine. An MaC ICE AC, rather than a MeC ICE AC or an EC ICE DC AC or EC ICE AC AC.
||At a minimum you'd want a more balanced unit, and
one that both latched onto multiple sides of the
window including the sill) and did so with gasketed
edges to form a seal.
||Beyond that, a few feet of pipe to carry the exhaust
above (I think propane exhaust rises) the window
probably makes sense.
||Yes, you'll definitely want some sort of flue. There are standards specifying how far an un-flued gas hot water system must be from windows etc. The hazards here would be similar.
||// Which one of you inspired the other to think that I was
writing about an engine powered air conditioner? //
||Neither of us inspired the other, rather both of us were
likely misled by your opening paragraph:
||// This idea answers the question, what happens if you
cross a window-installed air conditioner, with a portable
electric generator? //