Storing energy in the form of compressed air

[mahesh_chavan]

I want to use steam turbines to produce electricity by :
1. using steam produced by solar thermal energy
2. Wind mills will be used to compress air when above turbines will be using steam. At night when there is no sunlight this compressed air will be used to run steam turbines.
My question is how big storage tank is needed for storing compressed air produced by 45 KW eq. wind mills for say 4 hours ?
( I wil be using underground tanks )
Is this feasible ?

[Mad Scientist]

My question is how big storage tank is needed for storing compressed air produced by 45 KW eq. wind mills for say 4 hours ?
( I wil be using underground tanks )

Think large, think very very large, like maybe an underground cavern.

Is this feasible ?

In a word, No. Now obviously one can store energy in compressed air, it is done all the time and is used to run various air tools. But it is not an efficient method of energy storage.

To compress air requires energy, some of that energy is converted into heat warming the air. Then when stored in a tank that heat dissipates and its energy is lost.

[Galvatron]

In a word, No. Now obviously one can store energy in compressed air, it is done all the time and is used to run various air tools. But it is not an efficient method of energy storage.

To compress air requires energy, some of that energy is converted into heat warming the air. Then when stored in a tank that heat dissipates and its energy is lost.

Obviously you havent seen "steamboy" the movie!

I say Heck Yeah it can be done! Part of the problem is understanding the nature of physics and particles.

Every time we recite by rote what a thing "is" we stop being scientists and experimenters. What you stated has validity only in what has been tried to date. C'mon folks can we engage our brains a bit more?

[jibbguy]

Using Wind or Solar to compress the air, would be the key i think.

It is an "Alternative Storage Device" to batteries.... what it loses in total Energy Efficiency (and i think that is less than some would realize), it could at least partially make up in other ways... such as lowering the requirement for large amounts of batteries; or heavy duty (and much more expensive) high current Inverters, chargers, and controllers.

If you had the compressor running all day from solar panels, you could partially heat your Service Hot Water Tank with it (at or least use it with a Temper Tank to help i guess).

At night, you could use it to help cool the house in the summer as the stored air was being used, or for food refrigeration.

Plus, in the future there may be more clever and unique ways found to use the expanding air than simply running a conventional Air Motor with it to power an alternator... who knows

Tata Motors in India is mass-producing a car now, based on the designs of Guy Negre. You could use this solar or wind generated compressed air to power a vehicle.... lol if air powered vehicles are EVER ALLOWED INTO THE UNITED STATES or the country you live (they currently ARE NOT ALLOWED in the U.S.).

If what we have heard about the "MYT" engine from Raphael Morganto is "true"... it also makes a highly efficient air engine with more torque per volume than other designs. This added torque would make the equation much more on the "positive" side when using the air to generate electricity under load.

Air has some maintenance problems associated with it, "condensation" being the worst, probably. So does every tech i've ever heard of though, lol.

[tuzi]

Plus, in the future there may be more clever and unique ways found to use the expanding air than simply running a conventional Air Motor with it to power an alternator

Here is a interesting 'NEW' way to convert compressed air, invented in 1881.

A peristaltic motor, I have never seen one in use. I have seen a peristaltic pump that a rotating shaft pumps a liquid or gas but not a motor where compressed gas drives or rotates a shaft.

[Electrical_engineer]

Fascinating topic!

[Michael C]

Heat loss from the compressed air is a true problem. Also, a turbine acts differently on steam or on air. Usable steam has to be superheated (after water being evolved into steam, it needs to be heated once more in order to have a temperature margin to prevent too much condensing).

Run the turbine on compressed air alone, so it can be optimized for that energy medium. Use the solar/heat energy in some way to produce compressed air instead. Steam is the most economical way to transport heat energy. It would be possible to build a heat exchanger that produces compressed air, just a few spring loaded valves needed.

In electrics, 'back-EMF' is a known phenomena. The same thing happens when you close a water crane rapidly, the water pipes may vibrate and that's from a strong wave of 'water-EMF' from the cutoff. With a simple membrane pump, this backwards force have been harvested since the 1700's to raise water high above the level from where it came to the pump.

So, why not harvest that energy with the medium of air, in order to produce compressed air? Remember, speed generated from a certain steam pressure will have more energy than that very same pressure. Steam can pick up water from the outside and push it back into the steam vessel without any losses except heat energy. Search for the function of the Gresham injector for instance. Use this knowledge to build an air compressor with no other moving parts than spring valves or membranes. The sun could be the source of energy to that.

[Misael]

We are familiar with about the "MYT" website from Raphael Morganto is "true"... it also creates a very effective air website with more twisting per amount than other styles. This included twisting would create the situation much more on the "positive" part when using the air to produce power under fill.

[Realist]

Heat loss from the compressed air is a true problem. Also, a turbine acts differently on steam or on air. Usable steam has to be superheated (after water being evolved into steam, it needs to be heated once more in order to have a temperature margin to prevent too much condensing).

Run the turbine on compressed air alone, so it can be optimized for that energy medium. Use the solar/heat energy in some way to produce compressed air instead. Steam is the most economical way to transport heat energy. It would be possible to build a heat exchanger that produces compressed air, just a few spring loaded valves needed.

In electrics, 'back-EMF' is a known phenomena. The same thing happens when you close a water crane rapidly, the water pipes may vibrate and that's from a strong wave of 'water-EMF' from the cutoff. With a simple membrane pump, this backwards force have been harvested since the 1700's to raise water high above the level from where it came to the pump.

So, why not harvest that energy with the medium of air, in order to produce compressed air? Remember, speed generated from a certain steam pressure will have more energy than that very same pressure. Steam can pick up water from the outside and push it back into the steam vessel without any losses except heat energy. Search for the function of the Gresham injector for instance. Use this knowledge to build an air compressor with no other moving parts than spring valves or membranes. The sun could be the source of energy to that.

A very good book to compressed air is "Compressed Air" from Montana School of Mines.
Impulse water pumps utilize the velocity of water in a pipe, nothing else. The velocity is momentum; when the flow is halted (in a valve), the momentum must be converted, usually to a pulse in a smaller pipe. Height is limited by initial water velocity.

When air is compressed, the energy of that air is concentrated in heat. Compress air at sea level and 60F to 15 psi and the heat rise will be roughly to 140F. If this heat is lost, so is the energy required in compression. When the compressed air is used, it will cool to that temperature necessary to perform the work required. Easy checkout: compress air into a tank, let it cool, then release the pressure. Once you've done that, feel the tank and see how cold it is. That's lost energy.

Rules of physics, that's all.

[wings]

I want to use steam turbines to produce electricity by :
1. using steam produced by solar thermal energy
2. Wind mills will be used to compress air when above turbines will be using steam. At night when there is no sunlight this compressed air will be used to run steam turbines.
My question is how big storage tank is needed for storing compressed air produced by 45 KW eq. wind mills for say 4 hours ?
( I wil be using underground tanks )
Is this feasible ?

45000W * 4hours = 180 000 Wh
Compressed Air - Energy density = 90 - 100 Wh/kg (see the document)
Storage cilinders weight 180 000 Wh / 95 Wh/kg = 1895 kg !

download:

Comparison analysis - 22 June 2010
Dossier de Presse MDI et contact pour les Médias - Voiture à air comprimé - Véhicules propres - Technologie durable

[kamal11]

it is the best option to store energy.