What effect does scale have on heat transfer in a boiler?

Scale forms on the heat transfer surfaces of a boiler when minerals in the water precipitate and accumulate over time. This scaling significantly reduces the effectiveness of heat transfer. The scale acts as an insulating layer between the heat source and the water or steam that needs to be heated. Because heat must conduct through the scale before reaching the boiling water, the thermal conductivity of the system is diminished, leading to elevated temperatures on the boiler surfaces and potentially causing overheating.

Increased surface temperatures due to poor heat transfer can also lead to boiler tube failures and reduced system efficiency. Instead of enhancing performance, the presence of scale can cause operational issues, including increased fuel consumption and higher chances of equipment failure or safety hazards. The insulating effect of scale highlights the importance of regular maintenance and water treatment to minimize scaling and maintain optimal boiler performance.