Heat Transfer Calculator
Calculate heat transfer rates for conduction, convection, and radiation
Formula
Conduction (Fourier's Law):
$$\dot{Q} = \frac{k \cdot A \cdot \Delta T}{L}$$
Convection (Newton's Law of Cooling):
$$\dot{Q} = h \cdot A \cdot \Delta T$$
Radiation (Stefan-Boltzmann Law):
$$\dot{Q} = \varepsilon \cdot \sigma \cdot A \cdot (T_h^4 - T_c^4)$$
Where σ = 5.67×10⁻⁸ W/m²·K⁴ (Stefan-Boltzmann constant)
About this Calculator
This calculator computes heat transfer rates for three fundamental modes: conduction (heat flow through solid materials), convection (heat transfer between surfaces and fluids), and radiation (electromagnetic heat transfer). Select your transfer mode and input the relevant parameters to calculate heat flow.
How to Use
- Select the heat transfer mode (Conduction, Convection, or Radiation)
- Enter the surface area through which heat transfers
- Set the hot and cold temperatures
- For conduction: enter material thickness and thermal conductivity
- For convection: enter the convection heat transfer coefficient
- For radiation: enter the surface emissivity (0-1)
- Results show heat transfer rate (W) and heat flux (W/m²)
Frequently Asked Questions
What are typical thermal conductivity values?
Copper: 385 W/m·K, Aluminum: 205 W/m·K, Steel: 50 W/m·K, Glass: 1 W/m·K, Wood: 0.15 W/m·K, Air: 0.026 W/m·K, Insulation foam: 0.03 W/m·K
What are typical convection coefficients?
Natural convection in air: 5-25 W/m²·K, Forced air convection: 25-250 W/m²·K, Water natural convection: 100-900 W/m²·K, Water forced convection: 500-10,000 W/m²·K
What is emissivity?
Emissivity (ε) is a material's ability to emit thermal radiation, ranging from 0 to 1. A perfect blackbody has ε=1. Polished metals have low emissivity (0.02-0.1), while painted surfaces and oxidized metals have high emissivity (0.8-0.95).
When is radiation significant?
Radiation becomes significant at high temperatures (above 200°C) or in vacuum where convection is absent. At room temperature with air present, convection typically dominates for small temperature differences.
