Which is not a method employed to maintain the desired temperature of the spray water in air washers used in air conditioning systems?

Which is not a method employed to maintain the desired temperature of the spray water in air washers used in air conditioning systems?

a) an electric heater and fan
b) part of the spray water is recirculated and hot or cold water is added as required
c) the spray water if recirculated through a heat exchanger and is cooled by chilled water
d) the spray water is recirculated through a heat exchanger and is heated by hot water
e) a heating or cooling coil is directly mounted in the sump of the washer





Answer: A

Air washers used in air conditioning systems

Air washers used in air conditioning systems

a) only clean the air
b) only clean and cool the air
c) only humidify and dehumidify the air
d) humidify, heat, cool, dehumidify, and clean the air
e) only humidify, cool, and clean the air







Answer: D

Pan type humidifiers with plates

Pan type humidifiers with plates

a) consist of rotating plates in a pan partially filled with water
b) are placed in individual rooms to humidify the individual rooms
c) consist of a shallow pan, partially filled with water in which absorbent plates are placed and the pan is installed in the supply plenum of smaller warm air furnaces
d) consist of plates in a pan through which water is sprayed by a spinning disc or cone
e) can be a power type or a bypass type







Answer: C

It is not recommended to use an on-off switch for steam grid humidifiers because

It is not recommended to use an on-off switch for steam grid humidifiers because

a) fogging would occur
b) overheating would occur
c) misting would occur
d) wide fluctuations in relative humidity would occur
e) all of the above






Answer: E

Which type of humidifier breaks water up into a mist or fog?

Which type of humidifier breaks water up into a mist or fog?

a) A bypass humidifier
b) A welted element humidifier
c) An atomizing humidifier
d) An air washing humidifier
e) A steam grid humidifier







Answer: C

Relative humidity

Relative humidity

a) increases when the air temperature is raised without the addition of moisture to the air
b) remains the same when the air temperature is raised
c) decreases when the air temperature is raised without the addition of moisture to the air
d) remains the same when the air temperature is lowered
e) decreases when the air temperature is lowered without the addition of moisture to the air






Answer: C

Relative humidity is the amount of

Relative humidity is the amount of

a) moisture contained in the air compared to the maximum amount of moisture the air is capable of holding at the stated temperature
b) moisture contained in the air compared to the maximum amount of moisture the air is capable of holding, air temperature being irrelevant
c) air contained in the air-moisture mixture compared to the maximum amount of air the air-mixture moisture is capable of holding at the stated temperature
d) air compared to the amount of moisture in the air at any temperature
e) moisture contained in the air at 0 degrees C

Answer: A

Humidity in the air

Humidity in the air

a) increases when the air temperature decreases
b) increases when the air pressure decreases
c) decreases when the air pressure increases
d) decreases when the air temperature decreases
e) remains constant with air temperature changes






Answer: D

Wetted element humidifiers:

Wetted element humidifiers:

a. Are the same as pan type humidifiers
b. Can be either the power type or the bypass type
c. Have stationary plates placed in trays of water, and are installed in individual rooms
d. Have a lower humidification rate than the pan type humidifiers
e. Are the same as the atomizing humidifier








Answer: B

Dehumidification occurs in an air washer when which of the following occurs?

Dehumidification occurs in an air washer when which of the following occurs?

a. If the level in the bottom tank drops lower than the minimum level
b. If water temperature is heated above the dry bulb temperature
c. If spray water is cooled to a temperature below the dew point
d. Heating of the spray water
e. Air washers do not dehumidify.







Answer: C

The residential humidifier which is commonly used in the supply plenum of smaller warm air furnaces and consists of a shallow tray partially filled with water is called a:

The residential humidifier which is commonly used in the supply plenum of smaller warm air furnaces and consists of a shallow tray partially filled with water is called a:

a. Bypass humidifier
b. Wetted element humidifier
c. Steam grid humidifier
d. Pan type humidifier
e. Power type humidifier







Answer: D

The purpose of humidification is to:

The purpose of humidification is to:

a. Add moisture to the air during the cooling season
b. Add moisture to the air during the heating season
c. Remove moisture from the air during the heating season
d. Remove moisture from the air during the cooling season
e. Add moisture to the air during the cooling season





Answer: B

The outside air is a a temperature of -25°C, and is saturated. This air is drawn into the building and heated to 21°C. What is the relative humidity of the air after passing through the heating coil? (Air at -25°C holds a maximum of 0.0005 kg of moisture/kg of water, and air at 21°C holds a maximum of 0.015 kg of moisture/kg of water).

The outside air is a a temperature of -25°C, and is saturated. This air is drawn into the building and heated to 21°C. What is the relative humidity of the air after passing through the heating coil? (Air at -25°C holds a maximum of 0.0005 kg of moisture/kg of water, and air at 21°C holds a maximum of 0.015 kg of moisture/kg of water).

a. 3.3%
b. 0.015%
c. 0.5%
d. 10.6%
e. 4.5%





Answer: A

If air at 13°C can hold a maximum of 0.0032 kg of moisture per kilogram of air, what is the relative humidity if the air contains 0.0015 kg of moisture per 1 kg of air?

If air at 13°C can hold a maximum of 0.0032 kg of moisture per kilogram of air, what is the relative humidity if the air contains 0.0015 kg of moisture per 1 kg of air?

a. 100%
b. 2.13%
c. 0.4%
d. 47%
e. 32%








Answer: D

Air washers, used in HVAC systems, cannot:

Air washers, used in HVAC systems, cannot:

a. Cool air
b. Remove tobacco smoke
c. Dehumidify air
d. Heat air
e. Clean air







Answer: B

A disadvantage of the atomizing humidifier is:

A disadvantage of the atomizing humidifier is:

a. Its evaporation plates clog up due to the salt left behind after evaporation
b. The salts that were in the water before atomization and evaporation settle as white dust in rooms and ducts
c. It can be used only as an individual area or room humidifier
d. Its evaporation plates have to be replaced regularly
e. It has a lower humidification rate than the pan type humidifier







Answer: B

Air washers used in air conditioning systems achieve simultaneous heating and humidification by:

Air washers used in air conditioning systems achieve simultaneous heating and humidification by:

a. Cooling the entering air below its dry bulb temperature
b. Cooling the spray water to a temperature below the dry bulb temperature
c. Heating the spray water to a temperature above the dry bulb temperature of the entering air
d. Cooling the spray water to a temperature below the dew point of the entering air
e. Heating the entering air above its dry bulb temperature







Answer: C

Air humidifiers of the atomizing variety:

Air humidifiers of the atomizing variety:

a. Break up the water for humidification into small particles by either a spinning disc or spray nozzle and are place either in the warm air supply duct or in the area to be humidified
b. Spray water through plates to atomize the water
c. Have a lower humidification rate than the pan type humidifiers
d. Can be either the power type or the bypass type
e. Spray water through rotating pads to atomize the water







Answer: A

Steam grid humidifiers used in HVAC systems achieve humidification by:

Steam grid humidifiers used in HVAC systems achieve humidification by:

a. The installation of a steam coil in the entering air stream
b. The installation of a water coil in the entering air stream
c. Injecting steam directly into the rooms to be humidified
d. Injecting steam into the spray water of an air washer
e. Injecting steam in the supply air stream







Answer: E

Humidification in residences equipped with ducted warm air heating systems:

Humidification in residences equipped with ducted warm air heating systems:

a. Is not necessary because the humidity does not change with heating
b. Is provided for by placing a single humidifier in the furnace plenum or in the warm air duct
c. Is accomplished by installing a second heating system, such as hot water
d. Is supplied entirely by normal living processes such as cooking, washing, and breathing
e. Requires separate humidifiers for each heated area





Answer: B