Heat Transfer by Conduction

\[Q=\frac{kA(T_H-T_C)t}{L}\]

Variables

Qheat transferred (J)

kthermal conductivity (W/m·K)

Across-sectional area (m²)

Th[T_H]hot-side temperature (K)

Tc[T_C]cold-side temperature (K)

ttime interval (s)

Lmaterial thickness or length (m)

Description

What is this formula?

This formula calculates the amount of heat transferred through a solid material by conduction. Heat naturally flows from a region of higher temperature to a region of lower temperature, and the transfer rate depends on the material properties and geometry.

When to use it

Use this formula when analyzing heat flow through walls, insulation, metal plates, pipes, building materials, or any solid medium where conduction is the dominant heat transfer mechanism.

Example

Given:

k = 0.80 W/m·K

A = 2.0 m²

TH = 350 K

TC = 300 K

t = 3600 s

L = 0.10 m

Formula:

Q = kA(TH - TC)t/L

Substitution:

Q = 0.80 × 2.0 × (350 - 300) × 3600 / 0.10

Result:

Q = 2.88×10^6 J

Applications

Building insulation analysis, heat exchangers, furnace walls, thermal engineering, electronic cooling, pipe insulation, and energy efficiency studies.