traditional air conditioners work by condensing gas, and then letting it evaporate which makes its' surroundings cooler.
the question is: if heat is a form of energy, why is it not possible for us to find a way to EXTRACT the energy from the air, by means such as converting black body radiation (thus making it cooler), instead of INVESTING energy in the cooling process?
| nimo wrote: |
traditional air conditioners work by condensing gas, and then letting it evaporate which makes its' surroundings cooler.
the question is: if heat is a form of energy, why is it not possible for us to find a way to EXTRACT the energy from the air, by means such as converting black body radiation (thus making it cooler), instead of INVESTING energy in the cooling process? |
Doesn't extracting energy take energy? And doesn't anything energy/energy related gives you an output where you actually lose energy? Doesn't using energy create heat?Yeah, essentially you're not talking about anything new. Your proposed method is very similar to existing refrigeration techniques, except that you're talking about powering the process through heat extraction, which is just basically an inefficient method of doing so.
If I remember right, black body radiation occurs at very high temperatures. Possibly higher temperatures than one would like to be at before air conditioning was to start (rather, they would like the AC to kick in long before it got to that temperature).
There really isn't a way to purely extract energy to make a system cooler. Think about it, the heating and cooling is from the processing of chemical compositions in certain ways. One needs to invest energy to create a proces that will create the energy outcome desired. Plus there is the 2nd law of thermodynamics to consider, the concept of entropy. There is no process that we use that doesn't have a source of energy losses and any idea of radical cooling will have undergone a strict study of it in consideration for conversation of energy and the laws of entropy.
I'm sure scientists have considered what you proposed but have not found a process that would make such an ideal outcome.
| nimo wrote: |
traditional air conditioners work by condensing gas, and then letting it evaporate which makes its' surroundings cooler.
the question is: if heat is a form of energy, why is it not possible for us to find a way to EXTRACT the energy from the air, by means such as converting black body radiation (thus making it cooler), instead of INVESTING energy in the cooling process? |
You can't "extract" energy without having someplace to put it first. An air conditioner "extracts" heat energy by creating a body (fluid) with very low heat energy and letting the heat energy in the air transfer to that. Then that heat energy is discarded at the back by being radiated to outdoors.
What you're talking about is really just cooling a room by putting a very cold block of something in it. Like putting a block of ice in glass of water (except the primary means of heat transfer does not need to be conduction or convection). Would it work? Sure. The cold object would get hotter by absorbing the thermal energy from the room, and thus the room would get cooler.
But in order to make it work, you would *first* have to get the cool object to begin with. Unless you can find it naturally (bringing snow in from outside), you're going to have to invest energy in cooling something. So you're back to square one. | Ranti84 wrote: |
If I remember right, black body radiation occurs at very high temperatures. Possibly higher temperatures than one would like to be at before air conditioning was to start (rather, they would like the AC to kick in long before it got to that temperature).
There really isn't a way to purely extract energy to make a system cooler. Think about it, the heating and cooling is from the processing of chemical compositions in certain ways. One needs to invest energy to create a proces that will create the energy outcome desired. Plus there is the 2nd law of thermodynamics to consider, the concept of entropy. There is no process that we use that doesn't have a source of energy losses and any idea of radical cooling will have undergone a strict study of it in consideration for conversation of energy and the laws of entropy.
I'm sure scientists have considered what you proposed but have not found a process that would make such an ideal outcome. |
I was familiar with both facts (typical temperatures for black body radiation and the 2nd law of thermo), which made me even more confused.
if I remember correctly, there will always be SOME radiation generated by any substace. so why should I not be able to use a photoelectric cell (operating at the suitable wavelength to capture spontaneous black body radiation from the surrounding air) to store the energy as potential electric energy, for example?
I forgot to mention, in this way you are not ACTIVELY extracting the radiated energy, so it doesn't seem to contradict entropy or energy conservation...?You are close.
Photo voltaic cells can produce current.
Current passed through a bimetallic element creates a cold leg and a hot leg.
A recirculating fan can pass over the cold leg in the summer
and redirect it past the hot leg in the winter.
Same principle as the hot/cold Coleman coolers
that you can plug into a lighter socket,
http://www.amazon.com/SnackMaster-12-Volt-Personal-Size-Cooler-Warmer/dp/B000EAATW0/ref=pd_nr_hi_22/104-9450007-7319145?ie=UTF8&s=hi
just 10times the size. You might even be able to use a tethered weather balloon to create a cold junction of a thermo couple and bury the other side of the thermocouple (the hot junction) in the ground, and create an electrical current that might be significant enough to provide heating and cooling .
The use of ventilation heat pipes is a very good idea to increase overall system efficiency.
http://www.heatpipe.com/heatpipes.htm
