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## Homework Statement

A small reheating furnace wall consists of 200 mm of firebrick. The inner surface of the wall is at a temperature of 320 °C and the outside temperature is 35 °C. Calculate the rate at which heat is transferred, by conduction, through unit area of the wall. The thermal conductivity of the firebrick used can be taken as 1.8 W m–1 K–1.

If the outside surface area of the furnace is 50 m2estimate the heat losses through the furnace wall per hour.

## Homework Equations

Given equation:

ϕ = (kA(T_1-T_2))/L

## The Attempt at a Solution

Inputting values:

k=1.8 W m^(-1) K^(-1)

A=50m^2

T_1=320 ,T_2=35

L=200mm ⟶ 0.2m

ϕ= ((1.8)∙(50)∙(320-35))/0.2

=128 250 W

=128 250 J S^(-1)

The heat loss per hour = ϕ∙t

128 250 ∙ 3600

=461 700 000 J

= 461.7 MJ

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