Specific heat capacity

bbenoit · by **bbenoit** » 22/02/10, 22:00

Hello,

a question trots me for some time,

why do not we extract the energy of the fluids present on earth (water and air) by cooling them? the process requires energy, but could not this same energy be extracted from this same fluid? thus, the machine will feed a part of its production

there must be a pitfall no?

Christophe · by **Christophe** » 22/02/10, 23:39

Can you repeat the question again? : Cheesy:

Did67 · by **Did67** » 23/02/10, 09:08

1) This is what heat pumps (heat pumps) do. Except that you need a motor that drives the pump. It does not "pump" by itself. Energy goes from hotter to colder, as water flows from top to bottom. And never the opposite (except to "pump", that is to say to use energy!).

2) In virtue of a good old principle of thermodynamics (clearly, in this world, nothing is perfect), you need a cold source and a hot spring ... There are attempts to make machines with emer / deep and surface water ... Not easy ...

bbenoit · by **bbenoit** » 23/02/10, 11:24

yes, it's true that at the proofreading, it was not ultra-clear:

why a machine like a heat pump can not feed itself with some of the energy it extracts instead of an external power source?

maybe a theoretical performance problem no?

Christophe · by **Christophe** » 23/02/10, 11:42

This is a story of performance and temperature level (too low): in the current state of technology we can not self-power a heat pump .... but nothing in theory prevents it in fact. ..

In the future, if we develop PACs with COPs of 10 or higher and systems for converting thermal energy at low temperatures with good yields (1 / 3), then it is conceivable that a PAC can be self-powered. .

The 2) evoked by Did67 is the ETM which will find information here: https://www.econologie.com/forums/energie-th ... t4853.html

There was 10 about I had fallen on the PACES: Spontaneous Flow Heat Pump I do not know where it is since. But the inventor was galley at the time ...

I have to find some docs. The idea was good and thermodynamically valid but hard to test because it required micro engineering.

ps: another topic to think about, https://www.econologie.com/forums/moteur-par ... t9354.html

bbenoit · by **bbenoit** » 23/02/10, 11:49

Ah OK,

because most of the energy received by the sun is transformed into heat in the air and in the water,
it could therefore be exploitable

please

Christophe · by **Christophe** » 23/02/10, 12:01

Yes, but I think it would be easier to feed a PAC with PV solar panels ... and a small buffer battery to compensate for peaks start ...

It is accessible technologically immediately ... but the investment is obviously high ...

hic · by **hic** » 23/02/10, 17:23

bbenoit wrote:Hello,
a question trots me for some time,
why do not we extract the energy of the fluids present on earth (water and air) by cooling them? the process requires energy, but could not this same energy be extracted from this same fluid? thus, the machine will feed a part of its production
there must be a pitfall no?

Hi bbenoit
Extracting energy with minimum energy consumption : Mrgreen:

It's the Canadian well in winter and the provencal well in summer
goodbye Hic

dedeleco · by **dedeleco** » 05/05/10, 15:11

This is a story of performance and temperature level (too low): in the current state of technology we can not self-power a heat pump .... but nothing in theory prevents it in fact. .
then it is conceivable that a PAC can be self-powered.

Sidider this answer because totally impossible according to the second principle of Carnot which erects in principle this experimental observation that it is impossible to operate an engine with a single hot spring (a boat would leave ice behind him to move recovering the heat of water in ice!) or to multiply the calories with a heat pump walking on a single source of heat without motor: from 20 ° C one would pass to 100 ° C without source of energy !!!

We would warm up with nothing, without doing anything!
We would make perpetual movements like buns !!!

The vocabulary around heat pumps is misleading with the calories of the air, when the principle of Carnot is little known!
http://fr.wikipedia.org/wiki/Sadi_Carno ... ysicien%29
http://en.wikipedia.org/wiki/Second_law ... modynamics
The French version is too abstract !!

Christophe · by **Christophe** » 05/05/10, 18:35

Oh no!

We would not shoot with NOTHING but with the (weak) hot source delta source.

No calories (even less a watt) would be "created", just taken from the air and without this delta (demand for calories) it would not work ...

It has nothing to do with the perpetual movement because without heat exchanges, it would stop ... should find the theory of PACES because it was interesting.

But indeed it would heat "for free" without doing anything ... like the sun finally ... : Cheesy:

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Specific heat capacity

Specific heat capacity

Re: Specific heat capacity

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