Heat transfer area and boiler horsepower
Boiler horsepower is used to rate boiler capacities to deliver steam to steam engines.
One boiler horsepower is the amount of energy required to produce 34.5 pounds (15.65 kg) of steam per hour at pressure and temperature 0 psig (0 bar) and 212oF (100oC) - with feed water at pressure 0 psig and temperature 212oF.
One boiler horsepower is about 33475 btu per hour (about 9811 watts, 8436 kcal/hr).
Boiler horsepower can be calculated from the boiler heat transfer area
PBoHP = A / 17 (1)
PBoHP = boiler horsepower
A = heat transfer area (ft2)
PBoHP tends to be used only in the USA, Australia, and New Zealand. Be aware that the a boiler horsepower is not the commonly accepted 550 ft lbf/s and the generally accepted conversion factor of 746 Watts = 1 horsepower does not apply.
Boiler Conversion Ratios
|sq.ft. EDR steam||240||Btu per hr.|
|sq. ft. EDR water||160||Btu per hr.|
|Boiler hp||33.5||MBtu per hr.|
|Boiler hp||140||sq.ft. EDR steam|
|Boiler hp||223||sq.ft. EDR steam|
|Boiler hp.||34.5||lb. per hr. steam|
|lb. per hr. steam||970||Btu per hr.|
|to||divide by above||from|