Find Approximate BTU of Air in 10 Cubic ft of 95F Water

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    Air Btu Water
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Discussion Overview

The discussion revolves around calculating the approximate BTU of air in a system involving 10 cubic feet of water at 95°F, agitated with air at 15 psi and 65°F. Participants explore the necessary parameters and assumptions required for determining the enthalpy of the air, considering factors such as pressure, temperature, and heat exchange.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant seeks to find the BTU of air but is unclear about the terminology used, prompting others to suggest that they may be looking for the enthalpy of the air.
  • Another participant questions whether the inquiry is about reaching equilibrium or just the initial enthalpy of the air after it leaves the water, raising concerns about the conditions of the container.
  • A participant suggests that the water will warm the air to its temperature and evaporate into it, making it saturated, and recommends using a steam table to find the enthalpy.
  • The original poster acknowledges the need for equilibrium and expresses difficulty in achieving approximate results due to multiple unknowns, including heat exchange rates and additional heat sources.

Areas of Agreement / Disagreement

Participants generally agree on the need for additional information and assumptions to proceed with the calculation. However, there is no consensus on the specific parameters or the approach to take, as multiple viewpoints and uncertainties remain present.

Contextual Notes

Participants note the importance of assumptions regarding the system's conditions, such as whether the container is insulated or covered, and the nature of the pressure being referenced (gauge or atmospheric).

Denys.Ca
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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:
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The question is incomplete - the sentence appears to be missing some words. Could you try again please?
 
lol =)))

russ_watters: Please rephrase yourself
 
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.
 
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
 
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
 
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.
 
  • #10
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.
 

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