Janardan Rai Nagar Rajasthan Vidyapeeth 2007 Diploma Mechanical Engineering REFRIGERATION AND AIR CONDITIONING SYSTEMS - Question Paper
JRN Rajasthan Vidyapeeth University
DIPLOMA
SEMESTER - 6
REFRIGERATION AND AIR CONDITIONING SYSTEMS
Model Question Paper
DTA8/DTM8 REFRIGERATION AND AIR CONDITIONING SYSTEMS
Duration : 3 Hrs. Maximum Marks : 75
Instruction:
1. Question paper is divided into Group A, Group B and Group C
2. Each Group is 25 Marks
3. Figure to the right in bracket indicate marks.
4. Good Handwriting is expected
Group A (25 Marks)
Answer any three questions (Question 1 is compulsory)
(10) (5)
Q.1: What are different applications
of refrigeration?
Q.2: Draw flow diagram of simple vapour absorption refrigeration cycle and explain its working in short?
(10)
Q.3: What is Rotary Compressor? Give
its construction and working. Enlist advantages of rotary compressor over
reciprocating?
(10)
Q.4: How will you select a refrigerant
? Give point of selection . Give points to select according to application.
(10)
Q.5: What is thermal insulation? What
are the properties of good insulating materials?
Group B (25 Marks)
Answer any three questions (Questions 6 is compulsory)
(5)
Q.6: What are the applications of Air
Conditioning ?
Q.7: A refrigerating system operates on the reversed cannot cycle. The higher temperature of the refrigerant in the system is 40OC, while lower is -12OC. The capacity of the machine is 15 Tons of refrigeration?
(10)
Neglecting all losses find
(i) The co-efficient of performance.
(ii) The heat rejected from the system per hour.
(10)
(iii) The power required to drive the machine.
Q.8: What is Refrigerant? Give classification of it? Give desirable properties of refrigerant?
(10)
Q.9: Explain the heat transfer phenomenon
of evaporative cooling.
(10)
Q.10: Give construction and
working of following
(i) Screw Type Compressor, (ii) Thermostatic expansion value
Group C (25 Marks)
All Questions are Compulsory.
Q.11. Fill in the blanks (Each question carries 2 Marks, Total = 10 Marks)
(1) The amount of heat extracted in a given time is termed as _________________.
(2) In condenser vapour is _____ and ____ to saturation temperature , corresponding to condenser pressure.
(3) _________ is an absorption type of domestic refrigerator. It has no moving machinery so no noise.
(4) _________Is that type of fan in which the air flows parallel to axis .
(5) ___________ maintains a constant degree of superheat of evaporator outlet or compressor inlet.
Q.12 Multiple choice Question (Each question carries 2 marks) (10)
(1) Room total heat =
(a) RTH = TSH RLH (b) RTH = RSH +RLH (c) RTH = RSH RLH (d) None where RSH Room sensible heat RLH Room latent Heat
(2) Which is not a type of compressor.
(a) Reciprocating compressor (b) Rotary compressor (c) Screw type compressor (d) Bolt type compressor.
(3) Which is not a type of Humidifier.
(a) injecting the water (b) injecting the steam (c) By air washing (d) Evaporating the water.
(4) Human comfort conditions for summer are
(a) 24 C DBT and 50 to 60% RH. (b) 50C DBT and 24% to 30% R.H. (c) 35 DBT and 30 to 40% R.H. (d) 30 DBT and 20% to 50% R.H.
(5) Latent heat transfer given by the formula.
(a) Q"= ma ( hb ha ) (b) Q=" = mahBhA (d) None.
Q.13. Indicate whether following statements are True or False (Each question carries 1 marks, Total = 5 Marks)
(i) Evaporative cooling is mostly used in hot & dry weather ambient conditions.
(ii) Removal of moisture from air is called humidification.
(iii) Rectifier is a partial condenser.
|
(iv) C.O.P.
of refrigerant is where T1 = Higher Temperature, T2
= Lower Temperature
(v) Carbon-di-oxide is a refrigerant which is most suitable for ships.
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| Earning: Approval pending. |
