A food product is being frozen in a system capable of removing 6000 kJ of thermal energy. The product has a specifi c heat of 4 kJ/(kg C) above the freezing temperature of 2 C, the latent heat of fusion equals 275 kJ/kg, and the frozen product has a specifi c heat of 2.5 kJ/(kg C) below 2 C. If 10 kg of product enters the system at 10C, determine the exit temperature of the product..

Answer : The exit temperature of the product is,

Explanation :

Total heat = Heat lost by liquid + Latent heat of fusion + Heat lost by frozen

where,

Q =  Total heat = 6000 kJ

m = mass of product = 15 kg

= specific heat of liquid =

= latent heat of fusion =

= specific heat of frozen =

= initial temperature of liquid =

= final temperature of liquid =

= initial temperature of frozen = ?

= final temperature of frozen =

Now put all the given value in the above expression, we get:

Thus, the exit temperature of the product is,