Variables
Description
What is this formula?
Furnace efficiency measures the fraction of fuel energy that is successfully transferred to the process material being heated. It is a key indicator of thermal performance in fired heaters and industrial furnaces.
When to use it
Use this formula when evaluating furnace operation, comparing fuel usage, identifying heat losses, or optimizing thermal processes in refineries, petrochemical plants, and manufacturing facilities.
Example
An industrial furnace burns fuel providing 15,000 kW of thermal energy. The process stream absorbs 10,800 kW of useful heat.
Formula:
ηf = Qproc / Qfuel
Substitution:
ηf = 10800 / 15000
Result:
ηf = 0.72
The furnace efficiency is 72%.
Applications
- Fired heater analysis
- Refinery furnaces
- Petrochemical plants
- Heat treatment operations
- Energy efficiency studies
Note
This equation represents the overall thermal efficiency of the furnace. Actual performance is affected by stack gas losses, wall radiation losses, air leakage, burner performance, excess air, and fuel composition. Detailed furnace analyses often use heat-loss methods for greater accuracy.