Download AKTU (Dr. A.P.J. Abdul Kalam Technical University (AKTU), formerly Uttar Pradesh Technical University (UPTU) B-Tech 6th Semester (Sixth Semester) 2018-2019 RME061 Refrigeration Air Conditioning Question Paper
Printed Paes: 02 Sub Code: RME061
Paperwz? RouNo.I | | | I I I I I I I
B TECH
(SEM VI) THEORY EXAMINATION 2018-19
REFRIGERATION & AIR CONDITIONING
T ime: 3 Hours T and Marks: 70
Note: Attempt all sections If require any missing data; then choose suitably. Use of refrigeration
tables and psychrometric charts and steam tables is permitted
mwngocpr
SECTION-A
Attempt all questions in brief. (2x7=14)
What do mean by one tonne of refrigeration?
Define COP
Classify refrigerants.
De?ne GSHF and ADP?
What is the function of expansion device?
What do you mean by bypass factor?
Define cascade system applied to vapour compression system.
SECTION-B
Attempt any three of the following: (7x3=21)
A cold storage is to be maintained at -5?C while the surroundings are at 35?C The heat
leakage fromthe surroundings into the cold storage is estimated to be 29 kW. The actual COP
of the refrigeration plant is one-third of an ideal plant working between the same
temperaturesFind the power required to drive the plant.
What is the significance of multistage vapour compression system? Also explain the function
liquid intercooler in multistage compression system.
Draw a neat diagram of lithium bromide water absorption system and explain its working.
List the major field of applications of this system.
The readings from a sling psychrometer are as follows: Dry bulb temperature = 30? C; Wet
bulb temperature = 20? C; Barometer reading =740mm of Hg. Determine:
i. Dew point temperature
ii. Relative humidity.
iii? Speci?c humidity
iV. Degree of saturation.
Vt Vapour density.
Vi. Enthalpy of mixture per kg of dry air.
Explain the working of Cold storage with neat sketch.
SECTION-C
Attempt any one part of the following: (7x1=7)
The cock pit of a jet plane ?ying at a speed of 1200 kIn/h is to be cooled by a simple air
cooling system The cock pit is to be maintained at 25?C and the pressure in the cock pit is 1
bar. The ambient air pressure and temperature are 0.85 bar and 30?C. The other data available
is as follows: Cock-pit cooling load: 10 TR; Main compressor pressure ratio =4; Ram
efficiency = 90%; Temperature of air leaving the heat exchanger and entering the cooling
turbine = 60?C; pressure drop in the heat exchanger: 0.5 bars; Pressure loss between the
cooler turbine and cock pit = 02 bar Assuming the isentropic ef?ciencies of main
compressor and cooler turbine as 80%, find the quantity of air passed through the cooling
turbine and C. O.P. ofthe system. Take y = 14 and C1: = 1 kJ/kg Ki
Explain, with a neat sketch, the working principle of boot?strap type of air refrigeration
system with T-S diagram.
Page 1 of 2
RME061
Attempt any one part of the following: (7x1=7)
Discuss the effect of change in Suction and discharge pressure in vapour compression
refrigeration system?
In a 15 TR ammonia plant, compression is carried out in two stages with water inter-cooling
and ?ash inter-cooling and water sub-cooling. The particulars of the plant are as follows:
Condenser pressure = 12 bar, Evaporator pressure = 3 bar, Flash intercooler pressure = 6 bar,
limiting temperature for inter-cooling and sub-cooling = 20?C Draw the cycle on p-h chart
and estimate (a) the coefficient of performance of the plant, (b) the power required for each
compressor, (c) the swept volume foreach compressor if the volumetric ef?ciency of both the
compressors is 80%
Attempt any one part of the following: (7x1=7)
In an absorption type refrigerator, the heat is supplied to NH3 generator by condensing steam
at 2 bar and 90% dry. The temperature in the refrigerator is to be maintained at?5? C. Find the
maximum C.O.P. possible, if the refrigeration load is 20 tonnes and actual GOP. is 70% of
the maximum C.O.P, find the mass of steam required per hour. Take temperature of the
atmosphere as 30? C
De?ne between primary and secondary refrigerant Give the refrigerant number for the
following: CHCLFZ, CH2F-CF3, and NH3,
Attempt any one part of the following: (7x1=7)
What is the basic difference between the requirements for Comfon and Industrial air
conditioning? Explain in brief, the factor affecting Comfort air conditioning.
Discuss thermal analysis of human body.
Attempt any one part of the following: (7x1=7)
What is the function of Cold storages and what is their impOItance in today?s life? 2000
tonnes of potato are available at a temperature of 30 ?C It has to be preserved in a cold
storage at a temperature of 2?C. How much refrigeration is necessary? If this refrigeration is
to be obtained in 3days, what should be the capacity of the plant?
Explain the working of ice manufacturing in ice manufacturing plant.
Page 2 of 2
This post was last modified on 29 January 2020