**Related Resources: heat transfer**

### Heat Loss Through Wall Equation and Calculator

**Heat Transfer Engineering**

**Thermodynamics**

**Engineering Physics **

Heat Loss Through a Wall Equation and Calculator

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Preview: Heat Loss Through a Wall Calculator

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Where:

Q = Heat Steady State Transfer (W)

T_{1} = Temperature (°C)

T_{2} = Temperature (°C)

k = Thermal Conductivity (W/m · °C)

ΔT_{wall} = Change in temperature (°C)

R_{wall} = Junction thermal resisitance (°C/W)

Example:

Consider a 3-m-high, 5-m-wide, and 0.3-m-thick wall whose thermal conductivity is k = 0.9 W/m · °C . On a certain day, the temperatures of the inner and the outer surfaces of the wall are measured to be 16°C and 2°C, respectively. The rate of heat loss through the wall on that day.

The two surfaces of a wall are maintained at specified temperatures. The rate of heat loss through the wall is to be determined.

Assumptions

1 Heat transfer through the wall is steady since the surface temperatures remain constant at the specified values.

2 Heat transfer is one dimensional since any significant temperature gradients will exist in the direction from the indoors to the outdoors.

3 Thermal conductivity is constant.

Alternativeliy the steady rate of heat transfer through the wall by making use of the thermal resistance concept from

Where:

Substituting