Refrigeration & A/C Mock Test -1

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Which of the following statements are TRUE?

1 point

Surrounding air velocity affects convective heat transfer from the body only

Surrounding air velocity affects both convective and evaporative heat transfers from the body

Moisture content of the air affects both convective and evaporative heat transfers from the body

Surrounding air velocity affects evaporative heat transfer from the body only

Clear selection

Hermetic compressors were developed to

1 point

Improve energy efficiency

Improve serviceability

Reduce weight

Overcome refrigerant leakage problems

Clear selection

Which one of the following statements is correct ?

1 point

Evaporative cooling is a cooling and dehumidification process

Evaporative cooling is a cooling and humidification process

Evaporative cooling is not effective for hot and dry climates.

Evaporative cooling and sensible cooling is the same

Clear selection

The Apparatus Dew Point (ADP) for the cooling coil of an air conditioning system with high latent load compared to a system with high sensible load will be

1 point

Depends on air flow through the coil

Less

Remains Same

Clear selection

Yellow is the color code for which refrigerant

1 point

R402A

R503

R134A

R500

Clear selection

Which elements cause the ozone depletion in CFC?

1 point

Chlorine

Fluorine

Carbon

All of these

Clear selection

In a psychometric chart, which of the following statement is/are correct?

1 point

It provides plots for moist air conditioning.

It is seldom used for air conditioning design

It cannot determine WBT and DBT

It is used to determine properties of refrigerants.

Clear selection

A cold storage is to be maintained at -5℃ while the surroundings are at 35℃. The heat leakage from the surroundings into the cold storage is estimated to be 29 kW. The actual COP of the refrigeration plant used is 30% of an ideal plant working between the same temperatures. Find the power required (in kW) to drive the plant.

2 points

1.29 kW

1.12 kW

12.55 kW

14.42 kW

Clear selection

The reason for a person feeling more comfortable on a warm day if seated in front of an electric fan is that the

1 point

Body loses more heat by evaporation and radiation.

Body loses more heat by radiation

Metabolic heat production is reduced

Body loses more heat by convection and evaporation

Clear selection

In a 3 ton capacity water cooler, water enters at 30℃ and leaves at 15℃ steadily. What is the water flow rate per hour?

2 points

602 kg

2520 kg

60 kg

100 kg

Clear selection

The refrigeration system of an ice plant working between temperatures of -5℃ and 25℃ produces 20 kg of ice per minute from water at 20℃. The specific heat of water is 4.2 kJ/kg and latent heat of ice is 335 kJ/kg. The refrigeration capacity of the refrigeration plant is

2 points

8750 kJ/min

8380 kJ/min

9040 kJ/min

8010 kJ/min

Clear selection

The thermostatic expansion valve operates based on

1 point

Degree of superheat at exit of evaporator

Degree of super heat at exit of the compressor

Temperature of the evaporator

Pressure in the evaporator

Clear selection

1 point

1 only

2 Only

3 only

None of these

Clear selection

In a psychometric process, the sensible heat added is 40kJ/s and the latent added is 30kJ/s. the sensible heat factor for the process will be

1 point

0.57

1.5

0.3

0.2

Clear selection

Operating pressures of the refrigerants at the evaporator in the ascending order for any application are

1 point

R717,R22,R11,R12

R22,R717,R12,R11

R11,R12,R22,R717

R11, R12, R717,R22

Clear selection

If air is heated without changing its moisture content, the dew point will

1 point

Increase

Decrease

Remain the same

Unpredictable

Clear selection

The generally used comfort conditions required in air conditioned space in India are

1 point

25°C DBT and 60% relative humidity

15°C DBT and 50% relative humidity

30°C DBT and 60% relative humidity

25°C DBT and 50% relative humidity

Clear selection

1 point

1 only

1 and 2

2 and 3

1,2 and 3

Clear selection

An air-conditioned room of volume 10 m^3 has infiltration of air equivalent to 3 air changes per hour. Density of air is 1.2 kg/m^3, specific heat cp is 1 kJ/kg.K and temperature difference between room and ambient air is 20K. What is the sensible heat load due to infiltrated air?

2 points

0.2 kW

60 kJ/hr

12 kJ/hr

0.45 kJ/hr

Clear selection

Which of the following statements are TRUE?

1 point

Infiltration rate is uncontrollable

Infiltration load is not a part of the building load

Infiltration load is a part of the building load

Infiltration rate increases as the pressure difference across the building decreases

Clear selection

2 points

A-2; B-3; C-1;D-2

A-2;B-3; C-1; D-1

A-1; B-2; C-3; D-3

A-1; B-2; C-3;D-1

Clear selection

Which one of the following refrigeration system uses oil separator operating at -10℃?

1 point

System using R-12

System using R-22

System using R-502

System using NH3

Clear selection

Refrigeration is used in construction of dams etc. to

1 point

All of the above

Avoid crack development during setting concrete

Reduce cost of construction

Avoid water evaporation

Clear selection

When the air is passed through an insulated chamber having sprays of water maintained at a temperature higher than the dew point temperature of entering air but lower than the dry bulb temperature, then the air is said to be

1 point

Heat and dehumidified

Cooled and humidified

Cooled and dehumidified

Heat and humidified

Clear selection

1 point

1 and 4

1 and 2

1,2, and 4

1 and 3

Clear selection

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