AIR CONDITIONING NPTEL

100 CFM air flow rate is equal to

• 28.317 liters/s

• 47.195 liters/s

• 57.195 liters/s

• 38.317 liters/s

Consider the following statements: A psychrometer measures,

a. wet bulb temperature

b. dew point temperature

c. dry bulb temperature.

On these statements......is/are correct

• a

• b

• c

COP of a five star window air conditioner is greater than or equal to

• 2.7

• 2.9

• 3.1

• 3.3

When dry bulb temperature of air is equal to web bulb temperature

• Air is 100% saturated

• Air is 50% saturated

• Air is completely dry

• Air is at dew point temperature

Vapour can be treated a gas when

• Temperature of vapour > critical temperature

• Pressure of vapour < 10 kpa

• Temperature of vapour = critical temperature

• Pressure of vapour is > critical pressure

The ration of water vapour to mass of dry air in a given mixture is known as

• Relative humidity

• Absolute humidity

• Humidity ratio

• Degree of saturation

During adiabatic saturation process on unsaturated air, the

• DBT remains unchanged

• WBT remains unchanged

• DPT remains unchanged

• Saturation temperature remains unchanged

The comfort conditions in the air-conditioning are at

• 25°DBT & 100% RH

• 20°DBT & 80% RH

• 24°DBT & 60% RH

• 25°DBT & 40% RH

DPT line on psychrometric chart are

• Horizontal

• Vertical

• Curved

• Straight inclined sloping downward to the right

If the specific heats of dry air and water vapour are 1.00 kJ/kg-K and 1.88 kJ/kg-K respectively and the humidity ratio is 0.011, then the specific heat of moist air at 25°C and 50% relative humidity will be

• 1.869 kJ/kg-K

• 1.891 kJ/kg-K

• 0.9793 kJ/kg-K

• 1.0206 kJ/kg-K