Refrigeration And Air-conditioning — Summer 2019

Discuss the effect of following on the performance of a vapour compression system i. Effect of suction pressure ii. Effect of delivery pressure iii. Effect of superheating iv. Effect of sub-cooling of liquid.

An air refrigeration system operating on Bell-Coleman cycle, takes in air from a room at -60C and compresses it from 1.04 bar to 6.2 bar. The index of compression being 1.26. The compressed air is cooled to 250C. The ambient temperature is 180C. Air expands in an expander where index of compression is 1.36. Determine i. C.O.Pof the system ii. Quantity of air circulated per minute for production of 1500 kg of ice per day at 00C from water at 150C. iii. Capacity of the plant.

Enumerate desirable properties of an ideal refrigerant.

Explain Lithium-Bromide vapour absorption system with neat sketch. 0

Explain Boot strap air refrigeration system with neat sketch.

State the principle of steam jet refrigeration system. Write at least three advantages and three disadvantages of steam jet refrigeration over other systems

Give detailed classification of compressors used in refrigeration and explain any one rotary compressor.

Enlist various types of expansion valves used in refrigeration and explain any one with neat sketch.

Explain compound compression with multiple expansion valves and flash intercooling system.

Define following term related to psychrometry i. Saturated air ii. Dry bulb temperature iii. Relative humidity iv. Specific humidity v. Dew point temperature vi. Sensible heat factor vii. By-pass factor.

Enumerate and explain the components of cooling load estimate.

Discuss the factors affecting human comfort.

Atmospheric air at 15 0C DBT and 30% RH passes through a furnace and through a humidifier, in such a way that the final DBT is 32 0C and 40% RH. Determine1 i. Heat and moisture added to the air. ii. Sensible heat factor of the process.

Enumerate various methods of air-conditioning duct design and explain in detail the “Equal friction method”.

With neat sketch explain working of an Ice Plant.

Explain following terms with respect to fan i. Static fan pressure ii. Dynamic fan pressure iii. Specific speed iv. Static fan efficiency

Classify air conditioning systems. Explain Central air conditioning system with a neat sketch