This method is conceptually simple: it compares the energy output in the steam to the total energy input from the fuel. ASME PTC 4 vs PTC 4.1: Efficiency Study | PDF - Scribd
This paper outlines the procedures, calculations, and practical applications of ASME PTC 4.1, the American Society of Mechanical Engineers code for determining the thermal efficiency of steam generating units. The code provides two primary methods: the Input-Output Method (direct) and the Heat Loss Method (indirect). Emphasis is placed on the Heat Loss Method, which identifies individual stack and unaccounted losses to achieve higher accuracy. Key calculations for dry flue gas loss, moisture from hydrogen combustion, and radiation/convection losses are presented. Measurement requirements, correction curves, and uncertainty analysis are discussed. The paper concludes with a sample calculation and guidance for field implementation. asme ptc 4.1