Need help with BTU input calculation
Need help with BTU input calculation
(OP)
I want to calculate how much gas we would need to burn to heat the water in the package boiler up from ambient to 375F.
Can I just assume that I'm only heating the water at the boiler efficiency provided by the manufacturer? Or do I need to take into account the heating of the tubes, drum steel, membrane, etc?
My gut feeling is that heating the steel is negligible compared to heating all the water...





RE: Need help with BTU input calculation
RE: Need help with BTU input calculation
After I subtract initial enthalpy from final enthalpy, I also need to add in the heat of vaporization?
Thanks.
RE: Need help with BTU input calculation
Say the boiler runs at 125 PSIG, and the DA water temp is 227*F. The boiler can't count the "running start" from the feedwater temp. One lb of steam at 125 PSIG contains 1153 BTU. One lb of feedwater at 227*F has 195 BTU. 1153 - 195 = 958. The boiler needs to add 958 BTU to each lb of feedwater to make steam, in this case. At 80% eff, you'll need to get 1197.5 BTU of fuel to the burner for each lb of steam generated.