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Heat powered cooler? Answered

It's rather warm around here. And by "rather warm," I mean it's 105 in the shade, and it's 89 in the house with the swamp at full blast. Does anyone have an idea for powering a cooler with pure heat? Perhaps similar to those lightbulb-looking devices that have an inner bit that spins around when placed in direct sunlight, except that is running a little generator that is then running a computer fan, like the ice box air conditioner spotted on this site. The main thing is I'd like the device to actually be powered by heat. Just for the heck of it. Even if it's just heat mechanically powering something to power a fan that I could have just plugged into the wall. So no solar cells making electricity. I can make parabolic reflectors easily if needed, so don't be afraid to use them. What's the best way you can think of to cool off using heat? "Best" can include inefficient but really awesome, like a fresnel lens pointed at a boiler that is providing steam to run a gigantic fan. I'll go get my goggles, ray gun, and keys to the airship.

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NachoMahma (author)2008-08-09

. You can't run anything off of "pure heat." There must be a differential - just as with electricity, hydraulics, &c. Ie, one "side" has to be "hotter" (more energetic) than the other to do any work.
. Just about any of the "free" power sources you can find (photovoltaic, wind turbine, hydraulic ram, solar boiler, &c, can be used to drive your cooler.
.
. BTW, the "lightbulb-looking devices that have an inner bit that spins" thing is called a Crookes Radiometer. As you've probably figured out by now, they don't produce any power to speak of.

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Rishnai (author)NachoMahma2008-08-10

Ha, I guess you're right about the "pure heat," but it rules out photovoltaic (unless I heat something up until it glows, and then take the miniscule amount of power from that light hitting a PV to power something). In keeping with the Rube Goldberg-type concept, perhaps using a Crookes Radiometer and shining a laser through it to a detector of some sort. The more often the beam is interrupted, the faster an electric fan turns. Now I just need to figure out how to have a fan's power source be controlled by a laserbeam. If not powered by heat, it would at least be regulated by the amount of heat in the room.

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AnarchistAsian (author)Rishnai2008-08-24

"regulated by the amount of heat in the room"? i'm afraid that's called a thermostat, :P when the tempurature goes up, the ac turns on...

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Rishnai (author)AnarchistAsian2008-08-24

Har har har. Of course, if it ain't broke, it doesn't have enough features yet. Why have a regular thermostat when you can make a hideously overcomplicated one?

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AnarchistAsian (author)Rishnai2008-08-25

i totally agree with you! :D overcomplication is quite hilarious sometimes...

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Goodhart (author)Rishnai2008-08-24

The radiometer, to my knowledge, runs from radiant heat shining directly on it (like sunlight). If this is what you are looking for, then I apologize for my comment.

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got one of those hand made in germany, they're pretty cool.

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AnarchistAsian (author)2008-08-09

how about: get iceblocks from the grocery store and put them on a piece small "half pipe" (tilted down) then put a turbine (connected to a fan blade) at the bottom of it, when the heat makes the ice melt, the water will turn the turbine (with fan) to cool down. innefficient but it's an idea!

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killerjackalope (author)Rishnai2008-08-31

Right out of the Rube Goldberg guide to refrigerators....

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Goodhart (author)Rishnai2008-08-24

if you place all that above a chair you sit in, you can get further cooling from the water :-)

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AnarchistAsian (author)Rishnai2008-08-11

what time is it? instructable making time! we should make a chatroom!

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chuckr44 (author)2008-09-04

Ever hear of Roman cooling? It uses a 3 foot high, 10 inch wide "chimney" mounted on your roof. This air is heated up and rises. Then cool air is drawn through a hole in your floor. Chimney and hole are not connected. Anyway the hole is connected to about 100 ft of underground pipe. While air travels toward your house through this hole it is cooled to about 65F. Saw this on PBS. Pure genius. Invented by the Romans around 100BC.

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Rishnai (author)chuckr442008-09-05

Oh, that sounds awesome! It says something about me that my first thought was "I wonder how much fuel that would take?" not "why would I want to build I giant chimney on my roof and put a hole in the floor?"

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Kiteman (author)2008-08-24

As Nacho said, you need a heat differential. You can get stirling engines that run on the difference between a stove and the air above it to spin a fan.

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killerjackalope (author)Kiteman2008-08-31

Actually I have been thinking of a Stirling engine for hot places, where the cold side is placed underground, the hot is up above, assuming the differential is more than 4 Celsius... which it would be in most places, better yet is if these were pumping the likes of well water then they could be cooled by the water passing over...

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Rishnai (author)killerjackalope2008-09-01

I like that idea. You dig a dole around here (or go in a cave) and it's 55 degrees, all year round. So in the winter, the cold side could be above ground, and in the summer, the cold side is in the ground. Eeeeeeexcelent...

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killerjackalope (author)Rishnai2008-09-02

Yeah, I suspect that anywhere with geothermal heating possibilities would work really well in this case, especially in the likes of northern Europe, Iceland etc. where there is cold on top and heat below... The whole thing seems like a pretty good application for low maintenance Stirling engines...

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Rishnai (author)killerjackalope2008-09-02

Or northwest Wyoming. Oh, the possibilities...

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killerjackalope (author)Rishnai2008-09-02

This sounds promising...

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frollard (author)2008-08-31

http://dvice.com/archives/2008/08/solar_icemaker.php

Some engineering students did just that

works on the same principle as a propane refrigerator; use the heat to vaporize and pressurize the refrigerant, then, release said pressure to make ice. Plans ongoing to make it for the third world, no moving parts - when can you get your hands on one? blech?

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