What exactly is the formula?

plumbnelly

Two quick questions: What exactly is the formula for a boiler horsepower, as in " BHp = ?"

Also, what is the true-gas equation, when volume, pressure, and temperature are changing? Thanks.

bob_46

HP

One boiler horsepower=34,474 BTU/HR

plumbnelly

Boiler horsepower

On the Engineering Toolbox site, it says one boiler horsepower equals 33,479 BTU's. If you use the latent heat of melting formula where 970 BTU's will evaporate one pound of water, then one boiler HP will evaporate 34.5 gallons of water per hour. I'm still working on finding the true-gas equation.

plumbnelly

Boiler horsepower

On the Engineering Toolbox site, it says one boiler horsepower equals 33,479 BTU's. If you use the latent heat of melting formula where 970 BTU's will evaporate one pound of water, then one boiler HP will evaporate 34.5 gallons of water per hour. I'm still working on finding the true-gas equation.

Paul48

Try

Ideal Gas Law

bml207

EOS

Generally, engineers use steam tables to look up the properties of steam under specific conditions. Interpolation is acceptable if your conditions are not identical to those in the tables.



If you need an equation e.g. for computer simulation, etc, the equation of state used for low pressure steam (less than 50 psia) is the Ideal Gas Law. The deviation is very low (less than 1%) if you have dry steam.



The difficultly comes when you have very wet steam. In this case, you would need to select a different EOS (See the wikipedia page for Equation of State). These are emperical equations; there is no "true-gas" equation as such.

bob_46

Mistake

33,474 is correct . I can't even copy . You don't have to look far for these answers they are right at the top of the page , Conversion Factors . PV=NrT don't ask me to explain it .

If you google steam tables you can see the specific volume , temperature , pressure ,etc. for any condition you want . Try Sarco's web site lots of good stuff there .