A different concept of a battery

[(unknown)]

I'll keep this short and sweet.  Instead of a wind generator producing electricity, I suggest a wind driven air compressor storing compressed air in a large LP or anhydrous ammonia tank.  Use a air motor to drive a generator, a pressure regulator driven by the speed of the motor should give you optimal usage of your stored air pressure.

   2nd - Using solar water heaters on your roof and a geothermal energy from below.  A large water storage tank, commonly seen on farms, could store a massive amount of hot water, insulate it.  Use a sterling engine utilizing the hot and cold water to drive your generator.  I estimated that in the midwest this setup should give you 120V 100A service 24/7.

    I have been challenging myself to develop a sterling engine that can run off of compressed air as well to utilize both systems.  

    I am excited to see what everyone has to say and/or add to this.

[dnix71]

Compressed air has a very low efficiency for storing and retrieving energy because it heats up under compression and unless you can insulate the tank, the energy converted to heat is lost.

There are direct solar heat plants that drive turbines to make electricity.

http://www.esolar.com/news/press/2008_06_03

[wooferhound]

The first story here is one of my favorites . . .

http://www.fieldlines.com/story/2006/1/9/103933/9137

http://www.fieldlines.com/story/2004/10/23/11533/778

http://www.fieldlines.com/story/2005/8/24/135518/795

http://www.fieldlines.com/story/2004/10/6/11716/8670

http://www.fieldlines.com/story/2004/1/27/111333/466

http://www.fieldlines.com/story/2006/3/31/151542/513

[freejuice]

 I would be happy with a sterling engine that could generate about 5 hp, I could feed it a steady diet of pine trees, parts of pine trees,or any thing closely related to a pine tree while it went "put, put, put" while it turned a generator that was grid tied.

[Beaufort]

I've researched Stirling engines for RE and most are dead-ends.  It's just not comparable to other methods of energy conversion in terms of efficiency and cost.  A kW -scale Stirling has yet to be built, to my knowledge.  Some company though is developing a solar collector for the military that uses a Stirling to make power..so who knows.

Many stories here on compressed air...and I'll echo the sentiment that it's very inefficient.  However, I think there is merit in using solar heating to expand the air prior to use.  So, compress it cold and use it warm...it should make up some of the losses in the compression process, but I haven't run the numbers or heard of anyone doing this.

[Flux]

I tend to agree with your comments about Stirling engines in general for small scale RE but I think I need to correct one point. NV Plipips of Eindhoven did a lot of work on these engines and I am not sure what power level they got to, but I do remember that in association with Ford they had engines of sufficient power to power a bus so they were likely up in the 100kW power level.

I think the project was basically a success but the general public have become so accustomed to the characteristics of the internal combustion engine that at the time they wouldn't accept change. With the present green debate I suspect that if it was introduced now it might be accepted.

Flux

[Flux]

Sorry, that strange word should be Philips. ( doesn't pay to type with a cat on your lap).

Flux

[m8e]

"A kW -scale Stirling has yet to be built, to my knowledge."

A whispergen gives 0,8KW elecricity and 5.5kW heat, runs on either diesel or LPG(and possible biogas).

Stirling.dk makes stirlings that gives 35-140kW of electricity and run on wood chips.

Kockums AB have done stirling generators that gives 8-9kw, they also make the stirlings that some of the swedish submarines use... they run on diesel an liquid oxygen!

[Beaufort]

Thanks for the correction; I wasn't aware of the Philips project.  Kind of a strange area of development for them.

[REdiculous]

The first picture I saw of a kw-scale stirling engine was from an installation in Antarctica. The engine looked to be about half the size of a car.

[flynntastic]

With a turbine driven air compressor, you could have a wind powered car.

http://www.popularmechanics.com/automotive/new_cars/4217016.html

[Bruce S]

Pepa;

 On here has done some testing on direct drive air compressing from mills.

He may have some insight for ya as well.

He's built a HUGE "S" to make use of the wild wind at his place.

If he's watching he may jump in here too, this is/was one of his on-going trials.

PEPA? jump in here and lend a note or two:)

best of Luck!!

Bruce S