Compressed gas energy storage formula

[Petersenwill36]

TL;DR

Compressed gas energy storage formula

Hi,
I’m looking for formula to find the energy stored in a compressed gas for non ideal gases, for example, argon. The formula should also include the thermal energy caused by compression.

Thank you in advance.

 

[anorlunda]

Can't you use conservation of energy? If we compress a gas, energy out equals energy in minus energy leaked to the environment. I'm sure you know that, so what is the premise of your question?

 

[Petersenwill36]

Compressed air energy storage is the topic.

 

[anorlunda]

Compressed air energy storage is the topic.

OK. In that case you can use this formula $$Energy_{stored} = Energy_{in} - Energy_{lost}$$

But that's probably not much help. Compressors are not 100% efficient when compressing the gas. Turbines are not 100% efficient when re-expanding the gas. But there are no simple formulas for those inefficiencies.

So if there are no simple formulas, the next best thing is to just make a reasonable guess. 60% net efficiency for compression/expansion and conversion to/from electricity. However, if you let the gas sit overnight so that heat leaks to the environment, efficiency might shrink to 20%. Therefore, for how long it remains stored becomes an important parameter.

Are you assigned the task of designing compressed air energy storage?

 

[Petersenwill36]

Thank you for your help. I am looking for the amount of energy in joules stored in a pressurized gas. For example, the amount of energy required to compress argon to 1000 psi in a 2L vessel.