The comfort of human beings is affected by the atmospheric conditions surrounding them. Which of the following is not an atmospheric condition which affects comfort?

The comfort of human beings is affected by the atmospheric conditions surrounding them. Which of the following is not an atmospheric condition which affects comfort?

a) Temperature
b) Relative humidity
c) Saturation temperature
d) Air movement
e) Air cleanliness







Answer: C

During sensible heating the dry-bulb temperature and the wet-bulb temperature are raised, and

During sensible heating the dry-bulb temperature and the wet-bulb temperature are raised, and

a) the dew point remains unchanged
b) the specific humidity is increased
c) the specific humidity is decreased
d) the dewpoint temperature increases
e) the dewpoint temperature decreases







Answer: A

Using the psychrometric chart, find the relative humidity if the dry-bulb temperature is 25 degrees C and the wet-bulb temperature is 25 degrees C.

Using the psychrometric chart, find the relative humidity if the dry-bulb temperature is 25 degrees C and the wet-bulb temperature is 25 degrees C.

a) 50%
b) 90%
c) 100%
d) 95%
e) 60%








Answer: C

Which of the following statements about cooling and dehumidification is false?

Which of the following statements about cooling and dehumidification is false?

a) Air washers are used to dehumidify air.
b) When air leaves the washer it will be close to 100% relative humidity.
c) The spray water carries off the latent heat of condensation of the water vapour in the air.
d) Dry bulb temperatures are increased.
e) Dewpoint temperatures are lowered.







Answer: D

The intersection between the line running vertically from the point on the dry-bulb scale and the downward diagonally running line from the wet-bulb scale is defined as

The intersection between the line running vertically from the point on the dry-bulb scale and the downward diagonally running line from the wet-bulb scale is defined as

a) the Dewpoint temperature
b) the partial pressure
c) the reference point
d) the specific volume
e) the relative humidity







Answer: C

Which of the following properties cannot be found on the psychrometric chart?

Which of the following properties cannot be found on the psychrometric chart?

a. The dew point temperature
b. The partial pressure
c. The specific humidity
d. The enthalpy
e. The relative humidity







Answer: B

Using the psychrometric chart, find the enthalpy if the dry bulb temperature is 20°C and the wet bulb temperature is 15°C.

Using the psychrometric chart, find the enthalpy if the dry bulb temperature is 20°C and the wet bulb temperature is 15°C.

a. 40 kJ/kg
b. 45 kJ/kg
c. 55 kJ/kg
d. 50.5 kJ/kg
e. 42 kJ/kg








Answer: E

An increase in air flow increases heat loss of the body by which of the following methods:

An increase in air flow increases heat loss of the body by which of the following methods:

a. Convection and Conduction only
b. Conduction only
c. Evaporation and Convection only
d. Radiation, Evaporation, and Convection
e. Conduction, Convection, and Evaporation








Answer: E

During the winter, the majority of people feel comfortable when the effective temperature is approximately between:

During the winter, the majority of people feel comfortable when the effective temperature is approximately between:

a. 15 and 19°C
b. 21 and 24°C
c. 19 and 24°C
d. 17 and 22°C
e. 16 and 20°C








Answer: D

During sensible heating, only the _________________ decreases.

During sensible heating, only the _________________ decreases.

a. Relative humidity
b. Specific humidity
c. Dew point temperature
d. Specific volume
e. Wet bulb temperature









Answer: A

Using the psychrometric chart, find the relative humidity if the dry bulb temperature is 20°C and the wet bulb temperature is 15°C.

Using the psychrometric chart, find the relative humidity if the dry bulb temperature is 20°C and the wet bulb temperature is 15°C.

a. 50%
b. 58%
c. 52%
d. 68%
e. 62%







Answer: B

Evaporative cooling results in:

Evaporative cooling results in:

a. Heating and humidification of the air
b. Heating and dehumidification of the air
c. Cooling and humidification of the air
d. Cooling and dehumidification of the air
e. Cooling of air only








Answer: C

Using the psychrometric chart, find the enthalpy if the dry bulb temperature is 25°C and the wet bulb temperature is 20°C.

Using the psychrometric chart, find the enthalpy if the dry bulb temperature is 25°C and the wet bulb temperature is 20°C.

a. 86 kJ/kg
b. 57 kJ/kg
c. 33 kJ/kg
d. 50 kJ/kg
e. 65 kJ/kg







Answer: B

During the summer, the majority of people feel comfortable when the effective temperature is approximately between:

During the summer, the majority of people feel comfortable when the effective temperature is approximately between:

a. 15 and 19°C
b. 21 and 24°C
c. 19 and 24°C
d. 17 and 22°C
e. 16 and 20°C






Answer: C

Using the psychrometric chart, find the dew point temperature at a dry bulb temperature of 20°C and a wet bulb temperature of 15°C.

Using the psychrometric chart, find the dew point temperature at a dry bulb temperature of 20°C and a wet bulb temperature of 15°C.

a. 20°C
b. 14°C
c. 11.5°C
d. 10°C
e. 16°C






Answer: C

If 5.0 cubic meters per second of air enters a heating coil at 20°C dry bulb and 15°C wet bulb, and leaves the heating coil at 30°C dry bulb, what is the approximate volume of air leaving the coil?

If 5.0 cubic meters per second of air enters a heating coil at 20°C dry bulb and 15°C wet bulb, and leaves the heating coil at 30°C dry bulb, what is the approximate volume of air leaving the coil?

a. 6 m3/s
b. 5 m3/s
c. 5.2 m3/s
d. 4.2 m3/s
e. 5.7 m3/s







Answer: C

Air used for ventilating purposes in an office building should be kept within a certain range of relative humidity as indicated below:

Air used for ventilating purposes in an office building should be kept within a certain range of relative humidity as indicated below:

a. 30 to 50%
b. 30 to 70%
c. 40 to 50%
d. 50 to 60%
e. 10 to 30%







Answer: B

Using the psychrometric chart, find the specific volume if the dry bulb temperature is 20°C and the wet bulb temperature is 15°C.

Using the psychrometric chart, find the specific volume if the dry bulb temperature is 20°C and the wet bulb temperature is 15°C.

a. 0.859 m3/kg
b. 0.842 m3/kg
c. 0.90 m3/kg
d. 0.80 m3/kg
e. 0.87 m3/kg






Answer: B

People need considerable time to adjust when moving from one space to another, when temperature and humidity conditions vary widely. This may be described as?

People need considerable time to adjust when moving from one space to another, when temperature and humidity conditions vary widely. This may be described as?

a. Shock effect
b. Change in comfort zone
c. Comfort condition
d. Effective temperature change
e. Air/Motion effect







Answer: A

Effective temperature is defined as a measure of comfort that involves:

Effective temperature is defined as a measure of comfort that involves:

a. The effects of relative humidity only
b. The effects of air movement and wet-bulb temperature
c. The effects of dry bulb temperature and dew-point
d. The effects of wet bulb temperature, dry bulb temperature, and relative humidity
e. The effects of air movement, dry bulb temperature, and relative humidity







Answer: E