Heat Transfer, Refrigeration and Air Conditioning

MCQsQuestion.com has 239 Question/Answers about Topic Heat Transfer, Refrigeration and Air Conditioning

The most commonly used method for the design of duct size is the

The most commonly used method for the design of duct size is the
  • A. velocity reduction method
  • B. equal friction method
  • C. static regain method
  • D. dual or double method
  • Correct Answer: Option C

For air conditioning the operation theatre in a hospital, the percentage of outside air in the air supplied is

For air conditioning the operation theatre in a hospital, the percentage of outside air in the air supplied is
  • A. zero
  • B. 20
  • C. 50
  • D. 100
  • Correct Answer: Option D

The alignment circle is marked on the psychrometric chart at

The alignment circle is marked on the psychrometric chart at
  • A. 20°C DBT and 50% RH
  • B. 26°C DBT and 50% RH
  • C. 20°C DBT and 60% RH
  • D. 26°C DBT and 60% RH
  • Correct Answer: Option B

The conditioned air supplied to the room must have the capacity to take up

The conditioned air supplied to the room must have the capacity to take up
  • A. room sensible heat load only
  • B. room latent heat load only
  • C. both room sensible heat and latent heat loads
  • D. none of the above
  • Correct Answer: Option C

The comfort conditions in air conditioning are at (where DBT = Dry bulb temperature, and RH = Relative humidity)

The comfort conditions in air conditioning are at (where DBT = Dry bulb temperature, and RH = Relative humidity)
  • A. 25°C DBT and 100% RH
  • B. 20°C DBT and 80% RH
  • C. 22°C DBT and 60% RH
  • D. 25°C DBT and 40% RH
  • Correct Answer: Option C

Air conditioning means

Air conditioning means
  • A. cooling
  • B. heating
  • C. dehumidifying
  • D. all of these
  • Correct Answer: Option D

Which of the following statement is correct?

Which of the following statement is correct?
  • A. The human body can lose heat even if its temperature is less than the atmospheric temperature.
  • B. The increase in air movement increases the evaporation from the human body.
  • C. The warm air increases the rate of radiation of heat from the human body.
  • D. both (a) and (b)
  • Correct Answer: Option D

The optimum effective temperature for human comfort is

The optimum effective temperature for human comfort is
  • A. higher in winter than in summer
  • B. lower in winter than in summer
  • C. same in winter and summer
  • D. not dependent on season
  • Correct Answer: Option B

The index which corelates the combined effects of air temperature, relative humidity and air velocity on the human body, is known as

The index which corelates the combined effects of air temperature, relative humidity and air velocity on the human body, is known as
  • A. mean radiant temperature
  • B. effective temperature
  • C. dew point temperature
  • D. none of these
  • Correct Answer: Option B

The human body feels comfortable when the heat stored in the body is

The human body feels comfortable when the heat stored in the body is
  • A. positive
  • B. negative
  • C. zero
  • D. none of these
  • Correct Answer: Option C

When the temperature of the surrounding is higher than the temperature of the body, then the heat loss by convection from the body to the surrounding will be

When the temperature of the surrounding is higher than the temperature of the body, then the heat loss by convection from the body to the surrounding will be
  • A. positive
  • B. negative
  • C. zero
  • D. none of these
  • Correct Answer: Option B

A human body feels comfortable when the heat produced by the metabolism of human body is equal to the

A human body feels comfortable when the heat produced by the metabolism of human body is equal to the
  • A. heat dissipated to the surroundings
  • B. heat stored in the human body
  • C. sum of (a) and (b)
  • D. difference of (a) and (b)
  • Correct Answer: Option C

It is desired to condition the outside air from 70% relative humidity and 45° C dry bulb temperature to 50% relative humidity and 25° C dry bulb temperature (room condition). The practical arrangement will be

It is desired to condition the outside air from 70% relative humidity and 45° C dry bulb temperature to 50% relative humidity and 25° C dry bulb temperature (room condition). The practical arrangement will be
  • A. dehumidification
  • B. cooling and humidification
  • C. cooling and dehumidification
  • D. dehumidification and pure sensible cooling
  • Correct Answer: Option C

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 its dry bulb temperature, then the air is said to be

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 its dry bulb temperature, then the air is said to be
  • A. cooled and humidified
  • B. cooled and dehumidified
  • C. heated and humidified
  • D. heated and dehumidified
  • Correct Answer: Option A

In order to cool and dehumidify a stream of moist air, it must be passed over the coil at a temperature

In order to cool and dehumidify a stream of moist air, it must be passed over the coil at a temperature
  • A. which lies between the dry bulb and wet bulb temperatures of the incoming stream
  • B. which lies between the wet bulb and dew point temperatures of the incoming stream
  • C. which is lower than the dew point temperature of the incoming stream
  • D. of adiabatic saturation of incoming stream
  • Correct Answer: Option C
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