त 10000ME405122101 Pages: 2

Reg No.: Name:
APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY

Seventh Semester B.Tech Degree Regular and Supplementary Examination December 2021 (2015 Scheme)

Course Code: ME405
Course Name: REFRIGERATION AND AIR CONDITIONING
Max. Marks: 100 Duration: 3 Hours
Use of Refrigeration tables, Charts and Psychrometric chart is permitted.
PARTA
Answer any three full questions, each carries 10 marks. Marks
1 a) Explain processes in reversed Carnot cycle with P-V and T-S diagram. (5)

b) Capacity of a refrigerator is 600 tons when working between -5 °C and 20°C. (5)
Find the mass of ice produced within 24 hours when water is supplied at 10 ௦.
Also find the minimum kW required. Assume the cycle of operation is Carnot
cycle. Latent heat of ice = 336 kJ/kg.

2 a) Write a short note on the Joule Thomson Throttling experimentation and what (5)

is the condition of J-T coefficient for cooling?

b) Derive, with the help of T-S diagram, the expression for net work done ൧൨ (5)
actual reverse Brayton cycle with non-isentropic compression and expansion
processes and with pressure drops in cold and hot heat exchangers.

3 9) Explain the working of Bootstrap Air Refrigeration System with 1-8 diagram. (5)
b) Explain, with the help of schematic diagram, the Adiabatic Demagnetization of (5)

paramagnetic salts.
4 ஐ Explain, with the help of p-h and 1-5 diagrams, the effects of subcooling and (5)
superheating on the COP of vapour compression Refrigeration system.

b) A refrigerating machine using air as working fluid and working on closed Bell- (5)
Coleman cycle operates under the following conditions. Refrigerator
temperature = 150 K, cooler temperature = 300 K. The air temperature at the
entry of the refrigerator is 40 K less than the refrigerator temperature. Pressure
in the refrigerator = 1 bar, calculate (a) refrigeration effect (b) net work done
(c) COP of machine and (d) Cooler pressure. Assume expansion and
compression to be isentropic.

PART ‏تا‎
‎Answer any three full questions, each carries 10 marks.
5 9) Explain the two stage compression with intercooling and subcooling by (5)

external cooling source with the help of its p-h diagram.

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