In order to measure the deviation of utility boiler efficiency caused by the estimation method of heat loss in the current Performance Test Code for Utility Boiler(GB 10184—1988)

heat loss field test and uncertainty analysis of a 440t/h circulating fluidized bed(CFB)coal-fired utility boiler was carried out.The outside sulface of the boiler system was divided into 134 zones and 1 333 measurement points were arranged.At each measurement point

the surface temperature

ambient temperature

environmental wind speed were taken 3records respectively.After calculation

the heat loss of the boiler system and the uncertainty are respectively 0.731% and 0.08%.The test result is of high precision.However

according to the current national standard and industrial standard

the heat loss determined by these estimation methods is0.432%

leading to that the boiler efficiency has unilateral uncertainty of 0.382%.