forums energies: society, ecology and clean technologies

Hello,
I'm wondering about storing electricity in a form other than batteries
have you heard of compressed air? the compressor is charged during the sunshine and is emptied producing electricity.
cost
yield
possible autonomy
so many questions to which I have no idea the answers, if there are any who know ...
greg

I do not recommend this solution because the overall performance of the air is quite miserable ... to be convinced it suffices to compare the consumption of 2 systems doing the same job (I had the opportunity to do so):

1) an electric compressor + pneumatic motor

2) an electric motor connected directly

Compressor consumption to do the same job is around 8 to 10 times the power of the electric motor ...

Not surprisingly, a compressor with an efficiency of 0.6 and even less for the pneumatic motor 0.4 in the best of cases ...

An electric motor has a mechanical efficiency greater than 0.8 ...

I'm not even talking about the wear and tear of the different parts and the cost of installation ...

2) You will find a very good summary on storage here: https://www.econologie.com/stockage-de-l ... t-241.html

Do not hesitate to use the internal search engine: https://www.econologie.com/forums/search.php

Hello
Related to your question
http://www.dudus-company.com/SOLAIRE/autonomie.htm

In addition to Christophe's links which go around the question:
Electricity storage. Extract from the national energy research strategy. Thematic approach: energy efficiency.
http://www.debat-energies.gouv.fr/energ ... e-elec.htm
See you later

be careful not to compare with a workshop compressor and a pneumatic tool: the yields are catastrophic

real compressed air storage was already used successfully to make tractors in gassy coal mines in about 1920 ...

to obtain a good output a compressor with several successive piston and radiator of cooling between each stage is necessary: ​​if the air is not cooled before the next compression the following compression requires more energy and the output is bad

to make the engine you also need a series of piston engine with air heating between each engine: without these heating too cold air does not produce the same energy as compression

the heat emitted during compression is not a loss as it is equal to the heat absorbed during expansion

so a very good compressed air system could have a very good performance

this has a big advantage on the batteries: a compressed air tank without leakage does not lose energy like a battery which discharges doing nothing

but the downside is that it's too heavy and too expensive

compressed air mine tractors we were replaced by battery electric tractors as soon as we knew how to properly enclose the electrical equipment to make it explosion proof

chatelot16 wrote:the heat emitted during compression is not a loss as it is equal to the heat absorbed during expansion

Of course, but we must store this heat, because we would not need this compressed air system if we wanted to produce at the same time as we store , or did I miss something?

But storing heat is not easy either.

with good insulation and light support, it's easier!
as for the batteries what ...

do you know the generator from MDI, which works with a compressed air tank? -)

chatelot16 wrote:real compressed air storage was already used successfully to make tractors in gassy coal mines in about 1920 ...

Just like the Nantes tramway in the 20s too ... it was not for nothing that the solution was abandoned ...

jonule wrote:do you know the generator from MDI, which works with a compressed air tank? -)

We saw 2 photos, that's all.
When a laboratory independent of MDI can test it, we'll talk about it again ...

chatelot16 wrote:the heat emitted during compression is not a loss as it is equal to the heat absorbed during expansion

Icing of pipes is one of the technological problems linked to the use of compressed air precisely ...

So if you need an oil torch to heat the air ... the energy balance of the compressed air goes down a little ...

Overall assessment to see ...

reheating the air between the detents requires large bulky radiators if you want to do it with the heat of the air

if the temperature drops because these radiators are too small the energy supplied drops: it is good for a fixed installation, but for a light vehicle there is no place to put what is necessary to make a good heating by ambient air

I saw desciptions of compressed air trams where there was a small boiler to heat the air

in coal mines the cool produced by the air release was not a problem because it was always too hot