Question

The capacity of the refrigerator (working on reversed Carnot cycle) is 280 tonnes when operating between – 10°C and 25°C. 

Determine : 

(i) Quantity of ice produced within 24 hours when water is supplied at 20°C. 

(ii) Minimum power (in kW) required.

Answer 1

(i) Quantity of ice produced : 

Heat to be extracted per kg of water (to form ice at 0°C) 

= 4.18 × 20 + 335 = 418.6 kJ/kg 

Heat extraction capacity of the refrigerator 

= 280 tonnes 

= 280 × 14000 = 3920000 kJ/h 

∴ Quantity of ice produced in 24 hours,

(ii) Minimum power required :

∴ Power required = 145 kW.