Boiler Horsepower to Heat Output
Also known as BHP to BTU · boiler horsepower
Worked example: 100 BHP → 3,347,500 BTU/h = 981.06 kW — press Try an example to run it live, then adjust anything.
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Boiler Horsepower to Heat Output explained
Boiler horsepower has nothing to do with mechanical horsepower and everything to do with 1889. The ASME committee of the day defined one boiler horsepower as the steam required by a typical steam engine of one horsepower — 34.5 pounds per hour of steam "from and at 212 °F" — and since evaporating water at atmospheric pressure absorbs 970.3 BTU/lb, that works out to 34.5 × 970.3 = 33,475 BTU/h. It is roughly 13 times a mechanical horsepower, which catches out anyone who assumes the two are related.
A 100 BHP boiler is therefore rated at 3,347,500 BTU/h output, or about 981 kW. Two cautions when you use the number. First, this is output, not fuel input: at 80% combustion efficiency that same boiler burns roughly 4,180,000 BTU/h of gas, which is what the meter and the gas bill see. Second, the definition assumes feedwater already at 212 °F; a real boiler feeding 180 °F condensate or 55 °F makeup must supply the sensible heat too, so nameplate BHP always flatters the delivered steam rate slightly.
Boiler Horsepower to Heat Output formula
- = Heat output (W)
- = Boiler horsepower (bhp)
Missing one of these? Work it out first, then come back
- Heat output — Glycol Loop Heat Transfer (Capacity Derate), Cooling Tower Heat Rejection
- Boiler horsepower — Boiler Horsepower to Steam Rate