A civil engineering technologist is asked to design a freezing plant for Tony's Meat. The inside temperature of the freezer will be $-18C$ and the average outside temperature will be $22C.$

The following design consideration is to be investigated:

For the walls, floor and ceiling use:

$25cm$ of corkboard, lining a freezer with walls of $100mm$ concrete.

The inside area of walls, ceiling and floor is $850m^2$ total. Assume heat is lost equally through all four walls, floor and ceiling.

Calculate the heat lost in $1hr.$

Let $t_i=$ the interface temperature between the corkboard lining and the concrete walls, floor and ceiling.

$k_{\text{C}\text{o}\text{n}\text{c}\text{.}}=$

kca$\frac{l}{m}.$s$.$C $C$ corkboard. $=$

kca$\frac{l}{m}.$s$.$C $$

$t_i=$ interface temperature $=$

$C,\frac{H_{\text{C}\text{o}\text{r}\text{k}}}{A_{\text{C}\text{o}\text{r}\text{k}}}=$

kca$\frac{l}{m^2.s}$

$(2$ dec. Place$)$

$(4$ sig tigs$)$

$H=\frac{Q}{t}=$

kca$\frac{l}{1}hr.$

$(3$ sig. rigs.$)$