🔥 Convection & Heat Exchangers
Heat Transfer Coefficient Converter
Convert convective film heat transfer coefficients ($h$) and building overall $U$-values between metric ($\text{W/(m}^2\cdot\text{K)}$) and imperial ($\text{BTU/(hr}\cdot\text{ft}^2\cdot^\circ\text{F)}$) units.
💨 Free Air (10 W/m²K)
🌪️ Forced Air (50 W/m²K)
💧 Water Exchanger (2,500 W/m²K)
♨️ Condensing Steam (10k W/m²K)
🪟 Low-E Window (U = 1.4)
Input Coefficient
Standard Imperial (BTU/hr·ft²·°F)
17.61 BTU/(hr·ft²·°F)
W / (m²·K)
100.0 W/m²K
kcal / (hr·m²·°C)
85.98
cal / (s·cm²·°C)
0.002388
💡 Newton's Law of Cooling:
$$q = h \cdot A \cdot (T_{\text{surf}} - T_\infty) \implies 1\text{ BTU/(hr}\cdot\text{ft}^2\cdot^\circ\text{F)} = 5.6783\text{ W/(m}^2\cdot\text{K)}$$
Heat Transfer Coefficient & U-Value
The heat transfer coefficient ($h$) quantifies thermal convection between a solid surface and a fluid:
- Newton's Law of Cooling: $$\dot{Q} = h A \Delta T$$
- U-Value & Thermal Resistance: In building architecture, the overall heat transfer coefficient is termed $U$, related to insulation thermal resistance $R$ by $$R_{\text{SI}} = \frac{1}{U_{\text{SI}}}$$
- Conversion Factor: $1\text{ W/(m}^2\cdot\text{K)} = 0.176110\text{ BTU/(hr}\cdot\text{ft}^2\cdot^\circ\text{F)}$.