How To Calculate Hot Water Boiler Thermal Efficiency


Hot water boilers are commonly used in heating applications or thermal power plant, with the boiler supplying water to steam usually at 120°F to 220°F, but the value is not the invariant one, boiler manufacturer can design it based on specific requirement. As a heating equipment, a higher thermal efficiency is expected for higher thermal efficiency, higher return on investment. Then how can we calculate its thermal efficiency?
According to boiler manufacturer ZBG, the thermal efficiency of hot water boiler is the ratio of the total output water heat and the boiler fuel heat. Through measure and calculate boiler heat losses, to acquire the thermal efficiency, this is negative equation way, that is, Qr=Q1+Q2+Q3+Q4+Q5+Q6 KJ/Kg.
Qr:  hot water boiler input heat
Q1:  boiler output heat, that is, the effectively utilized boiler heat
Q2:  exhaust heat loss, namely the discharged heat by flue gas emission
Q3: fuel incomplete combustion heat loss, because the not completed combustion of the combustible fuel, the part of lost heat, called the incomplete combustion gas heat loss.
Q4: Solid incomplete combustion heat loss, due to the solid fuel not burning completely and the lost that portion of the solid fuel heat is called solid incomplete combustion heat loss.
Q5: radiation heat loss, due to the boiler furnace and pipe radiation, some heat might be lost, and this is called as radiation heat loss.
Q6: other heat losses.
Calculated by the above formula is only theoretical thermal efficiency of hot water boilers, for the specific boiler thermal efficiency, one can contact us and our engineer can give the accurate value. Our CFB hot water boiler usually has a high thermal efficiency up to 85%. 
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