Heat Flux Density Converter
Convert heat flux density between W/m², BTU/(h·ft²), and cal/(s·cm²). Heat flux is the rate of heat transfer per unit area, used in thermal engineering.
Common Heat Flux Density Conversions
| From | To |
|---|---|
| 1 W/m² | 0.3170 BTU/(h·ft²) |
| 1 BTU/(h·ft²) | 3.1546 W/m² |
| Solar constant | ~1,361 W/m² |
| Human body (resting) | ~50 W/m² |
Heat Flux Density Unit Definitions
- W/m²
- SI unit of heat flux density.
- BTU/(h·ft²)
- Imperial unit used in HVAC. 1 BTU/(h·ft²) = 3.155 W/m².
- cal/(s·cm²)
- CGS unit. 1 cal/(s·cm²) = 41,840 W/m².
- kW/m²
- 1,000 W/m². Used for concentrated solar and industrial processes.
Frequently Asked Questions
What is heat flux?
Heat flux (W/m²) is the thermal power transferred per unit area. Higher heat flux means more energy flowing through a surface per second.
What is the solar heat flux on Earth?
The solar constant is ~1,361 W/m² at the top of the atmosphere. After absorption and reflection, the average at the surface is ~170 W/m².
What heat flux is dangerous for electronics?
Modern CPUs can exceed 50–100 W/cm² (500,000–1,000,000 W/m²). Above ~100 W/cm² without active cooling, components overheat rapidly.