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
- 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
- A. zero
- B. 20
- C. 50
- D. 100
- Correct Answer: Option D
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
- 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)
- 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
- A. cooling
- B. heating
- C. dehumidifying
- D. all of these
- Correct Answer: Option D
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
- 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
- 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
- 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
- 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. 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
- 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
- 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
- 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