STUPIDSID
1(a)
Explain difference between vapour compression refrigeration system and vapour absorption refrigeration system.
4 M
1(b)
Explain the need of aircraft refrigeration. Draw reduced ambient air refrigeration cycle with neat schematic an T-S diagram.
8 M
1(c)
Define the term 'by pass factor' used for heating and cooling coil.
4 M
1(d)
What is the difference between heat pump and refrigerator. Derive the relationship for COP between refrigerator and heat pump.
4 M
2(a)
Explain the working of simple vapour compression cycle with schematic and p-h and T-s diagrams.
8 M
2(b)
100kW power is used for refrigeration system working on bootstrap air refrigeration cycle. Required data are given below:
Ambient air pressure = 1bar
Ambient air temperature = 288K
Compressor delivery pressure = 3.5bar
Cabin pressure = 1 bar
Maximum pressure = 5.6bar >br> Heat exchanger effectiveness for both heat exchanger = 0.85
Efficiency of main and auxiliary compressor is 0.83 and 0.75 resp.
Turbine effieciency = 0.77
Cabin is maintained at 28°C and 1 bar
Determine
i) Refrigeration capacity in TR
ii) COP
iii) Determine the percentage of turbine power used by auxillary compressor.
Ambient air pressure = 1bar
Ambient air temperature = 288K
Compressor delivery pressure = 3.5bar
Cabin pressure = 1 bar
Maximum pressure = 5.6bar >br> Heat exchanger effectiveness for both heat exchanger = 0.85
Efficiency of main and auxiliary compressor is 0.83 and 0.75 resp.
Turbine effieciency = 0.77
Cabin is maintained at 28°C and 1 bar
Determine
i) Refrigeration capacity in TR
ii) COP
iii) Determine the percentage of turbine power used by auxillary compressor.
12 M
3(a)
Explain the ozone depletion and global warming issues. Discuss desirable properties of good refrigerant and designation of refrigerant with example.
8 M
3(b)
A food storage locker has a capacity of 12 TR and operates between the evaportation temperature of -8°C and condenstion temeprature of 30°C. The refrigerant R-12 is sub-cooled by 5°C before throttling and the vapour is superneated by 2°C before leaving the evaporator. Assuming a twin cylinder single acting compressor running at 1000 RPM with L:D ratio 1.5.. Calculate:
i) COP os system
ii) Specific power required
iii) Diameter
iv) Stroke compressor having volumetric efficiency of 0.945 Draw p-h and T-s diagram.
i) COP os system
ii) Specific power required
iii) Diameter
iv) Stroke compressor having volumetric efficiency of 0.945 Draw p-h and T-s diagram.
12 M
4(a)
What are the types of expansion valves? Explain the working of the thermostatic expansion valve.
6 M
4(b)
The design conditions for an air conditions for an air conditioned hall are:
Inside condition 24°C, 60% RH
Outside 38°C DBT, 28°C WBT
Sensible heat gain = 45kW
Latent heat gain = 11.25kW
Infiltrated air = 1200m3/h
Coil ADP = 10°C
60% total air is re-circulated and mixed with conditioned air after cooling coil. Find
i) Condition of air entering hall
ii) Refrigeration load.
Inside condition 24°C, 60% RH
Outside 38°C DBT, 28°C WBT
Sensible heat gain = 45kW
Latent heat gain = 11.25kW
Infiltrated air = 1200m3/h
Coil ADP = 10°C
60% total air is re-circulated and mixed with conditioned air after cooling coil. Find
i) Condition of air entering hall
ii) Refrigeration load.
14 M
5(a)
What is aspect ratio? Discuss the different methods of duct design.
8 M
5(b)
Explain Li-Br Water vapour absorption system with neat sketch.
6 M
5(c)
Explain briefly types of condensers.
6 M
Write short note any five question from Q.6(a, b, c, d, e,f ,g)
6(a)
Cooling tower performance and selection
4 M
6(b)
Air conditioning and human comfort
4 M
6(c)
Deep sea water air conditioning
4 M
6(d)
Dairy process plant
4 M
6(e)
Types of psychrometric processes
4 M
6(f)
Steam jet refrgeration
4 M
6(g)
Controls used in Refrigeration and Air Conditioning.
4 M
More question papers from Refrigeration & Air Conditioning