The document contains information about air conditioning systems including: 1) Calculating the mass of infiltrated air into a room based on given heat loads and airflow rates. 2) Key factors that affect the effectiveness of a cooling tower. 3) Common ducts used in air conditioning systems and their purposes. 4) Recommended relative humidity and air change rates for central air conditioning systems.

1. 1) The following data were collected to design a air
condition system: Indoor air condition is 24 degree C DBT
and 60 % RH, Outdoor condition is 38 degree C DBT, 28
degree C WBT, Sensible heat load in the room 1,60,000 KJ/hr,
Latent heat load in the room is 40,000 KJ/hr, Total
infilterated air = 1200 m3/hr, The quantity of recirculated
air from the hall is 60% of total . Find mass of infilterated air.
A) 1320 kg/hr, B) 1330 kg/hr, C) 1350 kg/hr

2. If the air is sensibly heated, the dew point will be
increasing decreasing
remaining
same
Zero

3. Effectiveness of cooling tower depends upon
WBT of air DBT of air
Ambient
temperature of
air
Direction of
flow of air

4. Which duct is used to carry air from air conditioned
space to AHU?
Supply Return Exhaust Fresh air

5. How much is the general relative humidity produced by
central air conditioning system?
less than
40%
less than
60%
more than
40%
more than
60%

6. A passive method to keep the house comfortably warm by
solar conditioning in cold climatic condition is to paint the
eastern wall of
the house by
black paint on
its outer side
eastern wall of
house by black
paint on its
inner side
southern wall of
the house by
black paint on
its outer side
southern wall of
the house by
black paint on
its inner side

7. In the air-conditioned space, fan load is considered as
latent heat
gain
sensible heat
gain
both sensible
and latent
heat gain
not
considered as
load

8. The atmospheric air at 760 mm of Hg, dry bulb
temperature 15°C and wet bulb temperature 11 °C
enters a heating coil whose temperature is 41°C. If the
by-pass factor of the heating coil is 0.5, then what will be
the dry bulb temperature of the air leaving the coil?
28°C 29°C 30°C 26°C

9. Fresh air intake (air change per hour) recommended for
ventillation purpose in the air conditioning system of an
office building is
1.5 4.5 10.5 12.5

10. Which duct is used to carry air from air conditioned
space to AHU?
Supply Return Exhaust Fresh air

11. Central air-conditioning system is preferred when
refrigeration and air flow requirements are more than?
1 tonne and
500 m3/min
10 tonne and
1000 m3/min
20 tonne and
1500 m3/min
100 tonne and
10000 m3/min

12. Which type of compressor is used in domestic
refrigerator?
Centrifugal Axial
Piston type
Reciprocating
Miniature
Sealed Unit

13. An air washer can work as
Humidifier Dehumidifier Filter
All of the
above

14. The process in winter air conditioning is
Dehumidifica
tion
Heating and
humidificatio
n
Humidificati
on
Cooling and
dehumidifica
tion

15. The operation theatre in a hospital is to be air
conditioned. Suggest the percentage of outside air
being circulated in the theatre..
20 50 70 100

16. The Alignment circle is marked on the psychrometric
chart at
20°C dbt and
60% RH
26°C dbt and
50% RH
22°C dbt and
55% RH
30°C dbt and
75% RH

17. The state of supply air from the cooling air is represented
by a point of intersevtion of ----- with -------
RSHF line,
Saturation curve
GSHF line,
saturation curve
RSHF line, GSHF
line
Point of intersection
divides the RSHF
line in proportion of
BPF and (1-BPF)
where BPF is the by-
pass factor of the coil

18. For a typical sample of ambient air (at 35C, 75% RH
and Standard atmosphere pressure), the amount of
moisture in kg per kg of dry air will be approximately
0.002 0.027 0.25 0.75

19. The essential parameters to estimate cooling load from
air side across air handling units (AHU) / Fan Coil
Unit (FCU) are
Flow rate DBT, WBT RH%
ALL OF
THE
ABOVE

20. The required A/C size for comfort conditions for general
living room (12 ft X 12 ft) at residence is
<0.5 TR 1 to 1.5 TR >2.5 TR
Any of the
Above

21. A simple impulse turbine has wheel of 30 cm diameter
and runs at 12000 RPM. The nozzles are inclined at
20° to plane of wheel and exit velocity of steam from
nozzle is 850 m/s. Loss of velocity in blades is 10 %
and blades are symetrical. Determine Blade angles.
25.47° 35.47° 40° 54°

22. A simple impulse turbine has wheel of 30 cm diameter
and runs at 12000 RPM. The nozzles are inclined at
20° to plane of wheel and exit velocity of steam from
nozzle is 850 m/s. Loss of velocity in blades is 10 %
and blades are symetrical. Determine absolute velocity
at exit.
445.5 m/s 325 m/s 220 m/s 750 m/s

23. A simple impulse turbine has wheel of 30 cm diameter
and runs at 12000 RPM. The nozzles are inclined at
20° to plane of wheel and exit velocity of steam from
nozzle is 850 m/s. Loss of velocity in blades is 10 %
and blades are symetrical. Determine Blade efficiency.
25% 45% 50% 60%

24. The degree of reaction is defined as the ratio of
Heat drop in
the fixed
blades to the
heat drop in
the moving
blades
Heat drop in
the moving
blades to the
heat drop in
the fixed
blades
Heat drop in
the moving
blades to the
total heat drop
in the fixed
blades
Heat drop in
the fixed
blades to the
total heat drop
in the moving
blades

25. The ratio of work done on the blades per kg of steam
to the energy supplied to the blades is called
stage
efficiency
blading
efficiency
nozzle
efficiency
mechanical
efficiency