## NIFTEM-Refrigeration & Cold chain-ENG 212- End Semester Question Paper Dec 2017- 3rd Sem

*The information shared below is only to get a rough idea of NIFTEM’s end semester question paper pattern. However, questions proportion from the syllabus topics may vary every semester.*

**Important points-**

- Time- 3:00 hours
- Total Marks- 100
- Three parts A, B & C, in which Part A is compulsory of (30 marks) having Objective questions, MCQs, Fill in the blanks and matching type questions. Students have to answer the questions from Part-A on the paper itself. Time allotted for Part-A is 40 minutes
- Part B & part C consists of 40 marks and 30 marks respectively. Part B- 8 questions of 5 marks each & Part C- 3 Questions of 10 marks each. Time for Part-B and C is total of 2:20 hours.

**PART B **

### Answer any 8 questions from the following-

**1.** Discuss the importance of refrigeration and air conditioning.

**2.** Explain various refrigerants used in food industries.

**3.** Draw a schematic diagram of a Cannot cycle and explain its working principle.

**4.** Discuss various properties of refrigerants.

**5.** Explain the working principle of a *centrifugal compressor* with a neat sketch.

**6.** Explain mechanisms of freezing with a neat diagram.

**7.** What do you mean by food thawing? What are the factors influencing freezing time? Describe

the effects of freezing on the quality of food.

.

**8. **How long would it take to freeze an apple (10 cm diameter), if cold air at -30°C blows across it

to give a convective heat transfer coefficient of 100 Wm^{-2}K^{-1}?

For unfrozen apple, the values of density = 870 kg m^{-3}, specific heat = 3.6 kJkg^{-1}K^{-1} and thermal conductivity = 0.355 Wm^{-1}K^{-1}.

For frozen apple. the value of density = 760 kg m^{-3}, specific heat = 2.2 kJkg^{-1}K^{-1} and thermal

conductivity = 1.10 Wm^{-1}K^{-1}.

The moisture content of the apple is 0.88 (wb) and freezing temperature Is – 0.9°C. Assume that the apple is initially at its freezing point.

**9.** Discuss the principle of ice manufacturing and different systems used for ice manufacturing in industries.

**10. **680 kg of fish at 5°C are to be frozen and stored at -12°C. The specific heat of fish above freezing point is 3.182, and below the freezing point is 1.717 kJ/kg K. The freezing point is —2°C and the latent heat of fusion 1 KJ/Kg. How much heat must be removed to cool the fish and what is the percentage of latent heat?

**PART C**

### Answer any 3 questions from the following-

**1.** Discuss various criteria used for selecting a refrigerant.

**2.** What is a ton of refrigeration? What is the refrigeration effect? A refrigeration system produces 40 kg/hr of ice at 0°C from water at 25°C. Find the refrigeration effect per hour and TR.

If it consumes 1 kW of energy to produce the ice, find the COP. Take latent heat of solidification of water at 0°C as 335 kJ/kg and specific heat of water 4.19 kJ/kg°C.

**3.** Explain the working principles of any five food freezers with neat diagrams.

**4.** Derive Plank’s equation giving all necessary assumptions. Also, write limitations of the Plank’ equation.

**5.** How to calculate the total refrigeration load in a cold store?

*Best of Luck !!*

See other papers

NIFTEM-Basic Chemistry- End Semester Question Paper Dec 2019- 1st year

NIFTEM-Basic Electrical Engineering- End Semester Question Paper Dec 2019- 1st year

NIFTEM-Physics- End Semester Question Paper Dec 2019- 1st year

*Source- Question Papers collected by Soumen Roy*