Can a Hydrogen-Cooled Generator Run on Air Instead?

[IF007]

Hi,

Can someone help me in this matter:



I would like to know if it is possible to use air instead of hydrogen in a hydrogen-cooled generator. If it is possible, what would be the conditions to do it. If not please justify your answer (e.g. safety reasons, efficiency, what can go wrong, etc.)



Thanks

 

[Bob S]

I believe the following three items are important considerations in using hydrogen vs. air in cooling generator armatures:

1) The air gap between the armature and stator is minimized, limited by mechanical tolerances, in order to minimize the generator power factor. This is because the magnetic energy storage in the gap is much higher than in iron.

2) Hydrogen gas has less than half the viscosity of air (important for small air gap). Air viscosity between moving surfaces creates friction.

Use viscosity calculator in http://www.lmnoeng.com/Flow/GasViscosity.htm

3) Hydrogen has a much higher specific heat than air. This means hydrogen can store more heat than air.

http://www.engineeringtoolbox.com/spesific-heat-capacity-gases-d_159.html

Bob S

 

[dlgoff]

My knowledge of this is limited to what I've just read from a internet search. It looks like the main reason for using hydrogen is it's 7-10 times better coolant than air due to it's low density, high specific heat, and high thermal conductivity.

http://en.wikipedia.org/wiki/Hydrogen-cooled_turbogenerator"

I would think the biggest danger would be destroying your generator.

Edit: Bob beat me posting. Besides, his answer is more complete.

 

[Trankmar]

We operate a 140 MVA synchronous condenser which is also able to work in air with a 90 MVA limit on output. Therefore it should be possible to use the generator in air IF the manufacturer permits it.

Aside from the lower MVA rating the machine also vibrates a lot more when running in air.

mvh Martin

 

[mmurillos]

Hi,

Can someone help me in this matter:



I would like to know if it is possible to use air instead of hydrogen in a hydrogen-cooled generator. If it is possible, what would be the conditions to do it. If not please justify your answer (e.g. safety reasons, efficiency, what can go wrong, etc.)



Thanks

Could you please inform of any positve results, did you get any help/input converting H2 cooled to air cooled generators?.An article from GE a GER 4203 mentions the unit has to be 30% larger. We are also very interested in this matter please advise to << personal e-mail address removed by Moderators >>

 

[Enthalpy]

You guessed it, people care to use hydrogen because they have excellent reasons for it.

Its heat capacity per volume unit matches air (both are stiff diatomic molecules) but its heat conductiivity is MUCH bigger and also its inertia (and viscosity, less important) is much smaller.