Subtopic: Preservation of food by cooling and freezing
Question Statement:
Milk weighing 98000 N having specific heat capacity 3.8 kJ kg⁻¹ K⁻¹ is to be chilled from 40 °C to 5 °C in one hour in a chilling plant using a refrigerant whose coefficient of performance is 4.7. The total compressor power consumption assuming 100% efficiency is
Options:
(A) 79 kW
(B) 105 kW
(C) 79 hp
(D) 105 hp
Official Answer Key:
A
Step-by-Step Solution & Explanation
Mass of milk m = W/g = 98000/9.81 = 9989.8 kg. Heat to be removed Q = m·cp·ΔT = 9989.8 × 3.8 × 35 = 1,328,645 kJ over 1 h (3600 s). Refrigeration load = 1,328,645/3600 = 369.07 kW. Compressor power = Refrigeration load / COP = 369.07/4.7 = 78.5 kW ≈ 79 kW, matching option (A). (105 hp would be numerically close only by unit confusion, since 78.5 kW ≈ 105 hp is the coincidental distractor logic behind options C/D.)
Practice This in Real CBT Exam Interface
Test yourself with the official TCS-iON palette, virtual calculator, and immediate performance analytics.