Problem on Refrigeration cooling effect(N) (basic introduction)

Question: 

8000 liters of water at 25 ^oC  is to be converted into ice at -4 ^oC  in 1day.

Find the capacity of refrigeration system.

Take Specific heat of ice as 2kJ/kg-K  

Latent heat of ice as 336kJ/kg-K

Specific heat of water as 4.2kJ/kg-K  

Solution:  

Given Data:

M=8000lts

Temp of water= 25^oC

Temp of ice =-4 ^oC

Cp of ice = 2 kJ/kg-K  

Cp of water = 4.2 kJ/kg-k

Latent heat of water = 336 kL/kg-k

 

Sensible Heat of water:

   Q_AB     =mCp(A-B)

            = 8000x4.2(25-0)

            = 840000 kJ

Latent Heat

   Q_BC     = mL

            = 8000x336

            = 2688000 kJ

Sensible Heat of ice

   Q_CD  = mCp(C-D)

            = 8000x2(0-(4)) 84

            = 64000 kJ

Total Cooling effect(N)= Q_AB + Q_{BC +} Q_CD

            N = 840000+2688000+64000

            N= 3592000 kJ

       = 11.87 TR

Note: Ton of Refrigeration means refrigeration capacity in this problem