Cassel

Thermodynamic magic enables cooling without energy consumption

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1 hour ago, Cassel said:

and build power generator

to keep heating the

1 hour ago, Cassel said:

stirling engine

 

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Take something hot and put a peltier device on it. Charge a battery from the temperature gradient until thermal equilibrium. Use energy from the battery to cool down the thing a bit more.

That's the gist of it as I understand it. Nothing spectacular.

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Very useful, as you could theoretically make much more efficient refrigerators with this, but it hardly breaks the laws of thermodynamics. 

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1 hour ago, kerbiloid said:

to keep heating the

 

air from atmosphere is going to to heat engine...

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54 minutes ago, MinimumSky5 said:

Very useful, as you could theoretically make much more efficient refrigerators with this, but it hardly breaks the laws of thermodynamics. 

This. peltier elements is already used in small coolers but they have an low efficiency. Has been some other types of solid state coolers, and yes you can run an cooler with heat. 
its not an free energy machine more than an solar panel who is free energy after purchase and installation :)

More efficient coolers and AC would be an major benefit however. 
 

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7 hours ago, Cassel said:

air from atmosphere is going to to heat engine...

surrounded by the air

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Reading past the woo-woo hype, it seems like they have found a novel way to get thermal energy to act like other potential energy.

Normally it would violate the laws of thermodynamics for a weight to move up against a gravitational field without an external force, but when we use a pendulum it happens. The key is that you start the weight from an even higher position. As it swings down the energy transforms into another type (mgh -> mv^2) and back again (mv^2 -> mgh).

With this device, it appears that the heat energy between a hot object and room temperature transforms into another type of energy (probably electrical potential?) and then that energy transforms back again -- except that instead of using it to reheat the initial input like a pendulum swings back up, they use it to further cool the initial input.

It doesn't violate physics or thermodynamics any more than a pendulum does.

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As previous posts mentioned it is within the laws of thermodynamics, the 2nd specifically.

The key here is the peltier element. They are however quite expensive. The advantages of course are that there light in weight and have no mechanical moving parts so last a lot longer than the alternatives. I am sure for certain applications thermoelectric cooling does have some great advantages..

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Posted (edited)
On 4/21/2019 at 11:42 AM, Cassel said:

How this works? Can I use it with stirling engine and build power generator?

https://phys.org/news/2019-04-thermodynamic-magic-enables-cooling-energy.html

You could! As long as you had a big supply of clean water and dry air. You'd get unfortunately little power out of it though, probably a AAA worth of energy for evaporating a full 250ml cup of water, after it's all told.

 

The article's interesting... But I'm sorry to say they were beaten to the punch of pulling free energy from room temp water 75 years ago...

By this, earth shattering invention:

The drinking bird.

They'll keep drinking room temp water forever so long as you keep their cup full and the air dry. You could even harvest energy from their bobbing, but... not remotely enough to be useful. Same as in the article!

More sciency stuff:

Spoiler

 

In terms of practical useage, they invented an extremely expensive swamp cooler, which has been in use since the days of yore and are what make green houses cool. They work by evaporating water to cool things down!

If you live in a dry place, they actually work pretty dang well at cooling the house as long as you have a cheap source of clean water like an RO filter, so it's a good way to save money!

The thermodynamics of this is we're using dry air to evaporate water, creating a cold spot, (they then using the temp difference to drive a thermoelectric generator, which in their case is a peltier being run in reverse because.... ???). Anyways, if we left the process to run in a closed environment, the humidity in the air would soon reach 100%, and the process would slow to a stop.  Here we're just extracting energy from the reaction of Heat + H2Oliquid -> H2Ogas. The maximum amount of cooling that can be provided is called the 'wet bulb temperature', and is a convenient metric for the process. A normal wet bulb temperature is about 2-8C beneath ambient, but it can be a bit higher if the humidity is very low.

Their version is a bit less efficient than a standard swamp cooler though, so... not exactly sure where they're going with it! If you're patient enough to wait for 250ml of water to evaporate you should be able to just barely harvest enough energy to fill a AAA battery if you have very high quality parts in a dry environment. We could speed up the evaporation process by using a fan, but then we'd be using more energy than we collect.

 

13 hours ago, Starstruck69 said:

As previous posts mentioned it is within the laws of thermodynamics, the 2nd specifically.

The key here is the peltier element. They are however quite expensive. The advantages of course are that there light in weight and have no mechanical moving parts so last a lot longer than the alternatives. I am sure for certain applications thermoelectric cooling does have some great advantages..

They do! They're extremely inefficient though, often consuming much more energy than they move, so we avoid them when possible.

 

 

Edited by Cunjo Carl

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Well *technically* my fridge isnt "consuming" energy either, its just moves heat around form one place to another, just like this technique. Sure, it sucks some energy out of a powerline and my room now contains a bit more energy than was there before, but my fruit and veg are sitting at below ambient.

I'd wager a hat that the technique in question is about the same, just with different methods of moving heat from place to place.

 

I mean, its not like conservation of energy is being violated...

**cough** http://www.preposterousuniverse.com/blog/2010/02/22/energy-is-not-conserved/  **cough**

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