taking energy from the atmosphere...


by heartless
Tags: atmosphere, energy
heartless
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#1
Apr16-06, 10:16 PM
P: 214
Our atmosphere is continously being heated and energized by the sun. Has anyone ever actually developed an engine able to take this energy directly from the atmosphere or if not, why nobody was able yet to make one?
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dav2008
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#2
Apr16-06, 10:19 PM
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We have solar cells that take sunlight and convert it to electricity.

We have windmills that take wind and convert it to electricity.
heartless
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#3
Apr16-06, 10:44 PM
P: 214
yeah, but solar cells are actually taking energy from the sun light, but traveling through earth's atmosphere sun light will leave a lot of energy in the atmosphere I suppose. If a person gets energy directly from the upper atmosphere one gains much more free energy. Such energy could be more effective than direct sun light. And windmills, they work using wind (oh, what the knowledge ) and it cannot be accessible from every place of the world at any time. Sun for example always lights.

russ_watters
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#4
Apr17-06, 06:26 AM
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taking energy from the atmosphere...


Energy is only accessible if it is in motion from a source to a sink. So warm atmosphere sitting still does not provide a source of energy. Wind is thermal energy in motion and is the closest you can get to what you suggest.
gschjetne
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#5
Apr17-06, 10:29 AM
P: 97
Of course it's possible to directly extract the thermal energy in the atmosphere. Just set up a stirling engine with its warm piston in the atmosphere and the cold piston in a bucket of ice.

Just go figure why most people aren't doing this as we speak...
Longstreet
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#6
Apr17-06, 11:02 AM
P: 98
Since the ground level is warmer than high altitude I would put the hot piston on the ground and the cold one at high altitude. In fact weather does exactly this.
Cliff_J
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#7
Apr17-06, 11:07 AM
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Given the much higher density of water, using the wind-driven waves on the oceans as a source of energy seems to be a much less expensive solution than capturing the wind itself. Of course, there's just those pesky problems of building something large-scale in a very hostile environment....

Russ's point is spot on: If you could store the energy somehow (forget the atmosphere and lets say you just use the infrared spectrum of the sunlight on a black surface to heat water) then you could extract some of that energy as you discharge it back into the atmosphere.

Now, how about efficiency? With such a small temperature differential, you're not going to get much energy per unit of area. Even with nuclear reactors or a gasoline engine in a car or a river dam with a hydroelectric plant, the larger the differential the easier it is to increase efficiency.

So to power a typical home, you'd need an area closer to the size of the lot or larger. With a high efficiency home at a low lattitude, the use of PV solar cells and infrared hot water heaters (to use in showers) can capture more energy in a day than it uses. As long as you can handle paying $.25-35 per kWh of electricity, this is a reality today.
russ_watters
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#8
Apr17-06, 12:15 PM
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Quote Quote by gschjetne
Of course it's possible to directly extract the thermal energy in the atmosphere. Just set up a stirling engine with its warm piston in the atmosphere and the cold piston in a bucket of ice.

Just go figure why most people aren't doing this as we speak...
I hope that was sarcastic, but can't really tell.....where does the ice come from?
gschjetne
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#9
Apr18-06, 06:21 AM
P: 97
Your freezer! Just use a generator connected to the stirling to power the freezer. Then you get free energy! (Yes, that was sarcastic )

Anyway, the point is that you always need some kind of difference to convert energy from one form to another. A heat engine needs a temperature difference, a wind generator needs a pressure difference, a hydro plant needs a gravitational potential difference, an electric heater needs a potential difference.
Ricardhheitman
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#10
Apr27-06, 09:41 AM
P: 18
In the novel Atlas Shrugged , John Galt invented a motor that ran on the electric charge in the atmosphere , I suppose a kind of static electricity accumulator.

Lightning occurs when this static charge concentrates in clouds and a diiference in potential exists between the cloud and the earth.

On a smaller scale can we accomplish this task artificially , and what might its output in work be ?
Q_Goest
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#11
Apr27-06, 11:21 AM
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Lightning has been considered. There's an article in Wikipedia about it that says:
How hard would it be to build a power plant that harnesses the electricity generated by lightning? Then, store the electricity and use it on-demand on the electric grid? Pie-In-The-Sky?

This concept is perhaps not as impractical as it once was. The main limiting factor of implementing a lightning capturing scheme such as this was the inability to be able to store large amounts of electricity for later use. However, new Utility Scale Battery technology or other energy storage technologies such as Flywheels or Capacitors could be used to store the electricity captured from lightning in massive quanties, for later grid use.
I wonder how much hydrogen could be produced by electrolysis of water from a single lightning strike. I seem to remember that being looked at once.
Homer Simpson
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#12
Apr27-06, 06:41 PM
P: 191
I dont think that 30 degree C air really has that much energy available. Like mentioned, the solar cells are likely the most efficiant way to convert the sun energy.


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