reed on the state liscence app they want to know past experiance in btu.  what is the conversion from mw or kw to btu?

Dennis,

Thanks for the question.  The main conversion you will need for your experience affidavit will be Megawatts (or Kilowatts) to boiler horsepower, because the application requires a BHP or a boiler horsepower unit (a megawatt conversion is obviously for a large plant).

Although it lists btu input (they mean btu/hr) at one point on the form, horsepower is preferred.

Boiler Horsepower is a confusing issue, because a boiler horsepower is not the same as mechanical or other types of horsepower. 

For example:

1 Horsepower = 746 Watts = 2,546 btu/hour

Although this conversion is true for mechanical and other types of horsepower, it is not correct for boiler horsepower.

1 Boiler Horsepower is the amount of power required to change 34.5 pounds of water to 34.5 pounds of steam at 212 degrees Fahrenheit in one hour.

Each pound of steam requires the addition of 970.4 btu/lb of energy (latent heat at 212 Fahrenheit) to make the change from water to steam.  Therefore, in one hour a boiler must add 33,478.8 btu's (970.4 x 34.5) to change 34.5 pounds of water to 34.5 pounds of steam.

So, the conversion for boiler horsepower is:

1 Boiler Horsepower = 33,478.8 btu/hr. (instead of 2,546 btu/hr - huge difference)

Now, 1 Megawatt = 3,414,000 btu/hr

1 Megawatt (3,414,000 btu/hr) divided by 1 Boiler Horsepower (33,478.8 btu/hr) = 101.97 Boiler Horsepower per Megawatt.

In other words, 1 Megawatt = 101.97 Boiler Horsepower

Just multiply the number of Megawatts by 101.97 and you have your answer.  Again, this will not work for other types of horsepower.  Only boiler horsepower (BHP).

If you want to find the btu/hr input, it should be on the burner.  The conversion factor the state uses is 1 BHP = 67,000 btu/hr input.

I know I gave alot of detail here, but the fact that horsepower and boiler horsepower are 2 totally different numbers can be confusing if you don't know the details.

-Reed

P.S.  I couldn't find this conversion anywhere, so I had to derive it on the fly for you.  I double-checked my math, but you should probably check my math too, just in case. 

By the way, the conversion above is only for large power plants.  If you need to find the horsepower for licensing purposes for process or heating plants, just find the square feet of heating surface and divide by 10.  This number should be on the name plate or in the boiler documentation.  This is the preferred calculation.  It isn't very acurate, but it is an easy calculation and it's close enough for licensing purposes.

If you can't find the heating surface number, find the btu/hr input and divide by 67,000.

-Reed