# BTU of Air in Water

I've got 10 Cubic ft of water at 95F.

I'm agitating it with air at 15psi, with 65F temperature.

How can I find the BTU of air? Approximately.

Last edited:

russ_watters
Mentor
The question is incomplete - the sentence appears to be missing some words. Could you try again please?

lol =)))

I realize to solve this I will need some additional numbers.
This isn't a question from the book russ, that's what I've got. Tell me what's missing, I'll get it.

russ_watters
Mentor
The phrase "btu of air" has no meaning. Perhaps you are looking for the btu added to or taken away from the air? Or the enthalpy of the air?

You are right. I do need to find enthalpy of the air

russ_watters
Mentor
Are we waiting for an equilibrium or just looking for the initial enthalpy of the air after it leaves the water? Is the container insulated? Covered? Pressurized? Is that gauge or atmospheric pressure?

Is this homework?

This is just a project at the plant I'm at.

I'm looking for the initial enthalpy.
The container is open and under atmospheric pressure

russ_watters
Mentor
Ok, well a host of assumptions are required here, but basically the water will warm up the air to its temperature and evaporate into the air, making it saturated. You should be able to plug that into a steam table to find the enthalpy.

Now that You've said it, I do look for the equilibrium. The end result is to bring down the temperature of the 10 cu ft tank down.

Although, I see that it would be even quiet hard to come up with the approximate results, that I can apply, because there are too many unknowns. I have three heat sources and I don't have the heat exchange rate for them. All I have is the current temperature of the tank, psi of air entering, and it's temp.