Problem # $2$

During an industrial process, a container with $1,000kg$ of liquid water at a temperature of

$50C$ is stored in a well$-$insulated and sealed room with dimensions of $654m$ for later use.

The air in this room is initially at $15C$ and $95$kPa pressure. Assuming that the specific heats

of water and air are constant and equal to the specific heats at room temperature:

$($a$)$ What will be the equilibrium temperature of the enclosure?

$($b$)$ If an operator accidentally leaves the door partially open and upon returning $45$

minutes later finds that the temperature is $32C,$ what was the rate of heat loss

through the door during that time interval?

Problem # $3$

During milk production, it is heated from $4C$ to $93C$ in a heat exchanger. To perform this

task, steam at $150C$ is used, entering the exchanger at $150$kPa and exiting as saturated

liquid at the same pressure. Assume that the exchanger loses heat to the surroundings at a

constant rate of $3kW.$ For a milk flow of $2000k\frac{g}{h},$ determine:

$($a$)$ The mass flow rate of steam required $($in $k\frac{g}{h})$

$($b$)$ The volumetric flow rate of liquid water at the exit of the exchanger $($in $m\frac{3}{s})$

$($c$)$The amount of heat gained by the milk.