How do I convert a boiler rating from units of boiler horsepower (bhp) to heat input (lb/MMBtu)?
This conversion requires two steps. First the boiler horsepower value is converted to an energy basis by muliplying by 33,446 Btu/hr per Bhp. Since Bhp ratings are based on the amount on useful work a boiler performs, the efficiency losses in converting the heat input to this useful work must be accounted for. In general, a boiler is about 80 percent efficient in converting the fuel’s energy into useful work. Thus, the “Btu/hr” value must be corrected to account for the 20 percent loss. Example: 500 Bhp = 20.904 MMBtu/hr (500 bhp * 33,446 Btu/hr/Bhp * 1/0.80). For more information or assistance, call the Engineering Division at (805) 961-8800, or e-mail us at engr@sbcapcd.org.
