Problem $2$: A Combined Conduction and Convection Problem

Problem Description

A cold room used to store chilled food is constructed of brick on the outside, a foam insulation material in the middle and a wooden wall on the inside.

The aim is to maintain a constant chilled temperature within cold room.

$4$

Formula

$2$ points

Using the following information, determine what the overall heat transfer coefficient would be$.$

BrickWall

Thickness $=0\mathrm{.}35m$

Thermal conductivity $=0\mathrm{.}11W{m}^{-1}{K}^{-1}$

Convective heat transfer coefficient for air to brick $=12\mathrm{.}39W{m}^{-2}{K}^{-1}$

Foam Layer

Thickness $=0\mathrm{.}20m$

Thermal conductivity $=0\mathrm{.}019$

Wooden Wall

Thickness $=0\mathrm{.}016m$

Thermal conductivity $=0\mathrm{.}93W{m}^{-1}{K}^{-1}$

Convective heat transfer coefficient for wood to air $=31\mathrm{.}28W{m}^{-2}{K}^{-1}$