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.
- 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.
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-2K-1?
For unfrozen apple, the values of density = 870 kg m-3, specific heat = 3.6 kJkg-1K-1 and thermal conductivity = 0.355 Wm-1K-1.
For frozen apple. the value of density = 760 kg m-3, specific heat = 2.2 kJkg-1K-1 and thermal
conductivity = 1.10 Wm-1K-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?
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 !!
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Source- Question Papers collected by Soumen Roy