Power Engineering Ch131-136 (PowT 1243)
b
"An HVAC system that provides cooling and heating all year round is highly energy efficient but has a high initial cost. The system consists of two separate supply and return piping systems that are connected to separate coils". Which of the following systems fits the above description? Choose one answer. a. A single pipe system b. A four-pipe system c. A Hydronic heat pump system d. A three-pipe system e. A two-pipe system
b
"Free Cooling," with regard to HVAC system operation, refers to Choose one answer. a. Recycling of 100% return air to minimize cooling and dehumidification b. Manipulating mixed air dampers on cooler days to eliminate the need for mechanical cooling c. Manipulating mixed air dampers on warmer days to reduce the amount of mechanical cooling needed d. Using a low-temperature thermal mass to provide cooling during peak demand periods e. Using air washers to cool and dehumidify the air.
b
A disadvantage of the atomizing humidifier is: Choose one answer. 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
c
A kitchen exhaust fan reduces the calculated heat gain from the cooking appliances it serves, by a factor of Choose one answer. a. 10% b. 25% c. 50% d. 60% e. 75%
a
Air humidifiers of the atomizing variety: Choose one answer. 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
b
An air handling unit that draws in room air, conditions it, and then returns it into the room uses: Choose one answer. a. Fixed percentage outdoor air circulation b. Full re-circulation c. 100% outdoor air circulation d. Mixed air circulation e. Blended circulation
c
Dehumidification occurs in an air washer when which of the following occurs? Choose one answer. 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.
a
Electric motors give off _________ while running. a) sensible heat b) latent heat c) latent and sensible heat d) no heat to the atmosphere e) solar heat
a
For which HVAC system is the central fan usually provided with variable inlet vanes, so that the air supply duct pressure can be maintained at a setpoint? Choose one answer. a. Variable air volume system b. Hydronic heat pump system c. Dual duct system d. Fan coil unit with make-up air system e. Constant air volume system
b
Heat gains by conduction are calculated on the assumption that: Choose one answer. a. Solar heat varies from hour to hour as sun changes position b. Solar heat should be considered separately c. Construction details are irrelevant d. The "U" value is not used e. Heat is conducted at the same rate through roofs, walls, and windows.
b
Humidification in residences equipped with ducted warm air heating systems: Choose one answer. 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
d
Humidifying units that use a small fan to draw warmer air from the furnace plenum or from the room force the air through the wetted pad and return the air to the room, are called: Choose one answer. a. Pan type humidifiers with plates b. Atomizing humidifiers c. Bypass type humidifiers d. Power type wetted element humidifiers e. Industrial pan type steam grid humidifiers
d
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
d
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? Choose one answer. a. 100% b. 2.13% c. 0.4% d. 47% e. 32%
c
In a constant air volume system with perimeter heating which of the following elements are fluids in the air handling unit? i) Heating coils ii) Cooling coils iii) An air mixing section iv) Filters v) A humidifier vi) A dehumidifier a) i, ii, iii, and iv b) i, ii, v, and vi c) ii, iii, iv, and v d) i, iii, and v e) iii only
d
In order to keep humidifiers in top working condition the plates of plate type units should be cleaned by soaking them in a slightly acidic solution and then washing them in soapy water to remove: Choose one answer. a. Dirt b. Grease c. Soot d. Mineral salts e. Corrosion on the plate
e
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
c
Locating HVAC equipment in mechanical rooms is preferred: Choose one answer. a. So that larger equipment can be used b. To make the maintenance easier c. So that maintenance may be performed without disturbing occupants d. To make maintenance more difficult e. So that all equipment is close together
c
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
e
Steam grid humidifiers used in HVAC systems achieve humidification by: Choose one answer. 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
c
The ______________ is a unitary air conditioning system that uses a direct expansion refrigeration system to provide cooling and dehumidification, serving a local area without using ductwork. Choose one answer. a. Unit ventilator b. Rooftop unit c. Window air conditioner d. High velocity terminal re-heat system e. Multi-zone system
e
The performance of a heat pump system (or C.O.P.) is the ratio of: Choose one answer. a. Heat output divided by heat input b. Heat input divided by energy output c. Energy input divided by energy output d. Energy input divided by heat output e. Heat output divided by energy input
d
The types of humidifiers used for residential purposes are: Choose one answer. a. Air washers, wetted element, and atomizing b. Pan, atomizing, and air washers c. Pan, hot water, and air washers d. Atomizing, wetted element, and pan e. Pan, steam, and atomizing
c
To maintain space conditions during heating this system zone thermostat reduces the air flow to a minimum of 20% before modulating the output of the heat supply. Choose one answer. a. Hydronic heat pump system b. Fan coil unit with make-up air system c. Variable air volume system d. Dual duct system e. Constant air volume system
a
When is the capacity of a heat pipe at a maximum? Choose one answer. a. When the evaporator is lowered below the horizontal b. When the evaporator is raised above the horizontal c. When the system is placed vertically with the evaporator on top d. When the system is placed vertically with the condenser on top e. When the system is level
b
When looking at building function to select a system which of the following factors are considered? i) Physical size of the building ii) Climatic conditions iii) Amount of zoning required iv) Funds available for the system v) Occupancy periods vi) Need to operate certain areas off-hours a) i, ii, and vi b) iii, v, and vi c) i, iii, iv, v, and vi d) ii, v, and iv e) i, iii, iv, and vi
b
Which of the following air handling systems is not appropriate for a single zone application? Choose one answer. a. A packaged air conditioner b. A dual duct system c. A unit ventilator d. A rooftop unit e. A single zone constant air volume system
c
Which of the following statements about the unit ventilators is false? Choose one answer. a. The units are used in areas with limited available floor space b. The units provide individual room temperature control c. The units provide cooling only d. The units provide heating and/or cooling e. Room air is mixed with outside air
c
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
c
A common complaint against the fan coil unit with make-up air is: Choose one answer. a. The response is very slow when first turned on b. The unit must be shut off when the room is unoccupied c. The fan noise is excessive d. The fan stirs up a great deal of dust e. The unit requires too much maintenance
c
A refrigeration system used in HVAC service, that can provide both heating and cooling, is a Choose one answer. a. Run around system b. Heat valve c. Heat pump d. Regenerative system e. Thermal wheel
e
A small residence located in a tropical climate may require which of the following elements of an air conditioning system: i) heating ii) cooling iii) humidification iv) dehumidification v) ventilation a) i and ii b) i, iii, and v c) ii and iii d) iv and v e) ii, iv, and v
c
A system consists of two finned tube heat exchangers. Where is the preconditioning coil of this system located? Choose one answer. a. On the suction side of the pump b. On the discharge side of the 3-way mixing valve c. In the duct work handling outside air d. At the end of the charging unit e. In the ductwork handling exhaust air
d
A system used extensively in hotels and motels due to its minimal space requirement, relatively low initial cost and high degree of individual zone control is called: Choose one answer. a. A hydronic heat pump system b. An induction system c. A variable volume system with perimeter heating d. A fan coil unit with make-up air system e. A compartmental atomizing system
d
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
c
Air washers used in air conditioning systems achieve simultaneous cooling and humidification by: Choose one answer. a. Heating the spray water to a temperature above the dry bulb temperature of the entering air b. Cooling the spray water to a temperature below the dew point temperature of the entering air c. Using spray water that is above the dewpoint of the entering air, but cooler than the dry bulb temperature d. Heating the entering air above its dry bulb temperature e. Cooling the spray water to below the dry bulb temperature of the incoming air, but above its wet-bulb temperature
c
Air washers used in air conditioning systems achieve simultaneous heating and humidification by: Choose one answer. 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
b
Air washers, used in HVAC systems, cannot: Choose one answer. a. Cool air b. Remove tobacco smoke c. Dehumidify air d. Heat air e. Clean air
e
Buildings require heat sources to: Choose one answer. a. Offset the heat gain from the atmosphere b. Replace the ventilation air c. Reduce the humidity of the outside air d. Replace the exhaust air e. Offset the building's heat losses
d
Cross contamination is a disadvantage for which of the following heat recovery systems? Choose one answer. a. A run around system b. A heat pipe c. A heat tube d. A thermal wheel e. A heat valve
d
Heat is lost from a building in the following ways: Choose one answer. a. Convection, evaporation and radiation b. Infiltration, condensation and conduction c. Evaporation, conduction and radiation d. Conduction, radiation and convection e. Infiltration, evaporation and convection
d
Heat load from people in a room is mostly affected by: Choose one answer. a. The size of the people b. Smoking c. The number of people d. The activity of the people e. The building occupancy class
c
Heat lost from a building is: Choose one answer. a. Dependent on the shape of the openings in a building b. Independent of indoor air temperature c. Greater on windier days d. Independent of outside temperature e. Dependant on barometric pressure
a
If operating personnel from an old building are going to be transferred to the new building the system installed in the new building will be the same as in the older building because all the personnel are familiar with that system. This type of system selection is based mainly on which of the following factors? a) Building owner's considerations b) Geographical location c) Building layout d) Operating costs e) Maintenance requirements
d
In a central air conditioning system, supplementary units are located in each zone to provide additional: Choose one answer. a. Ventilation b. Humidity Control c. Air circulation d. Heating e. Filtering
a
In an HVAC air-handling unit, temperature control that uses face and bypass dampers: Choose one answer. a. Closes the bypass damper and opens the face damper to direct air through the coil b. Closes both the bypass damper and the face damper to direct air through the coil c. Opens the bypass damper and closes the face damper to direct air across the coil d. Increases air flow through the bypass to increase air temperature e. Modulates the hot and cold deck airflows to maintain a constant supply air temperature
c
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
a
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
c
The aspect of air conditioning that is responsible for replenishing stale indoor air with outside air is Choose one answer. a. Heating b. Cooling c. Ventilation d. Humidification e. Air circulation
b
The condensate that drains from the evaporator of a window air conditioner is: Choose one answer. a. Drained on the floor b. Drained to a pan below the condenser fan where it is thrown against the condenser coil and evaporates c. Piped to a drain on the evaporator side of the unit d. Used to add humidity to the room air e. Circulated over the evaporator coil to keep it clean
d
The constant volume system with perimeter heating provides air from the air-handling unit in the central mechanical room at approximately: Choose one answer. a. Ambient temperature b. 22°C c. 10.5°C d. 12.5°C e. 15°C
b
The fact that the system can be treated against corrosion is an advantage for which system? a) A run around system b) A heat pipe c) A heat pump d) A thermal wheel e) A heat valve
b
The funds available for the air conditioning portion of the building refers to which factor of system selection? a) Building function b) Capital cost c) Building layout d) Operating costs e) Maintenance requirements
b
The heat recovery system that employs a single exchange unit consisting of a casing split into two sections and a segmented rotating wheel 300 mm thick and 1 to 3.7 m in diameter is called a: Choose one answer. a. Run around system b. Thermal wheel c. Heat pipe d. Heat valve e. Heat pump
e
The heat recovery system which has a capillary wick structure consisting of fine circumferential striations machined on its internal surface is called a: Choose one answer. a. Heat valve b. Run around system c. Heat pump d. Thermal wheel e. Heat pipe
d
The heat recovery system which makes use of an underground heat exchange coil is called a: Choose one answer. a. Run around system b. Thermal wheel c. Heat tube d. Heat pump e. Heat pipe
a
The most common system installed in most residences where the furnace is located in the basement and provides conditioned air via ducts to each room is called a: Choose one answer. a. Forced air system b. Single zone, constant air volume system c. Low velocity terminal re-heat system d. Multi-zone system e. Unit ventilator
a
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). Choose one answer. a. 3.3% b. 0.015% c. 0.5% d. 10.6% e. 4.5%
c
The provision of outside air into a building does not: Choose one answer. a. Provide "makeup" air b. Replenish the oxygen supply c. Dehumidify or humidify the air d. Remove odors e. Ventilate the building
b
The purpose of humidification is to: Choose one answer. 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
a
The quickest method of calculating air infiltration into a building is the Choose one answer. a. air change method b. crack method c. solar method d. conduction method e. building pressurization method
d
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: Choose one answer. a. Bypass humidifier b. Wetted element humidifier c. Steam grid humidifier d. Pan type humidifier e. Power type humidifier
a
The run around coil heat recovery system uses a _____ coil in the inlet air duct and a _____ coil in the exhaust air duct. Choose one answer. a. Preconditioning, recovery b. Heating, cooling c. Cooling, heating d. Recovery, conditioning e. Heating, recovery
d
The system which runs as a refrigeration system used for air conditioning purposes in the summer and can be modified to run in reverse in cooler weather is called a a) runaround system b) heat valve c) heat pump d) heat pipe e) thermal wheel
d
The terminal reheat air handling system has very high energy consumption because: Choose one answer. a. The large volumes of air that it must supply b. The resistance to flow created by the duct work c. Excessive air leakage and air seepage in the ductwork d. It cools the air for the solar radiation heated zones and then reheats the air for the remaining zones e. Hot deck coils must be energized year-round to provide adequate dehumidification
d
The ventilation rate of a building is determined based upon the greater of the Choose one answer. a. Solar heat rate and CFM rate per person b. Conduction rate per person and solar heat rate c. CFM rate and conduction rate per person d. Infiltration rate and CFM rate per person e. None of the above
b
Thermal conductivity (λ) may be defined as the: Choose one answer. a. Quantity of heat flow per unit time (in Watts) b. Ability of a material of uniform thickness to transmit heat (W/m°C) c. Heat transfer through a one-metre cross-sectional area of a particular material with defined surfaces (W/m2°C) d. Heat flow per unit time through one square metre of a material when exposed to a differential temperature of 1 degree Celsius (W/m2°C) e. Reciprocal of thermal conductance (m°C/W)
e
Thermal resistance (R) may be defined as the: Choose one answer. a. Quantity of heat flow per unit time (in Watts) b. Ability of a material of uniform thickness to transmit heat (W/m°C) c. Heat transfer through a one-metre cross-sectional area of a particular material with defined surfaces (W/m2°C) d. Heat flow per unit time through one square metre of a material, when exposed to a differential temperature of 1 degree Celsius (W/m2°C) e. Reciprocal of thermal conductance (m2°C/W)
a
Thermal transmission may be defined as the: Choose one answer. a. Quantity of heat flow per unit time (in Watts) b. Ability of a material of uniform thickness to transmit heat (W/m°C) c. Heat transfer through a one-metre cross-sectional area of a particular material with defined surfaces (W/m2°C) d. Heat flow per unit time through one square metre of a material, of a particular composition and thickness, when exposed to a differential temperature of 1 degree Celsius (W/m2°C) e. Reciprocal of thermal conductance (m°C/W)
d
Thermal transmittance (U) may be defined as the: Choose one answer. a. Quantity of heat flow per unit time (in Watts) b. Ability of a material of uniform thickness to transmit heat (W/m°C) c. Heat transfer through a one-metre cross-sectional area of a particular material with defined surfaces (W/m2°C) d. Heat flow through one square metre of a material, per unit of thickness and unit of time when exposed to a differential temperature of 1 degree Celsius (W/m2°C) e. Reciprocal of thermal conductance (m°C/W)
d
To calculate the heat gain from fluorescent lighting, add the wattage ratings of the lamps and multiply by: Choose one answer. a. 0.2 b. 0.5 c. 4.1 d. 1.2 e. 2.1
d
To offset internal and external heat gains, a building requires Choose one answer. a. A humidifier b. A heat source c. Ventilation d. A cooling source e. A dehumidifier
d
Two methods of calculating air infiltration into a building are the: Choose one answer. a. Crack and solar method b. Air change and solar method c. Crack and conduction method d. Air change and crack method e. Conduction and solar method
c
Very low humidity does not result in Choose one answer. a. Cracked lips b. Static electricity build-up c. Evaporation of moisture on the skin decreases d. At sufficiently high room temperatures people still feel cool e. Wood furniture and floor squeaks and cracks
b
Wetted element humidifiers: Choose one answer. 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
a
What is the name of the heat recovery system that consists of two finned tube heat exchangers? Choose one answer. a. A run around system b. A heat valve c. A heat pump d. A heat tube e. A thermal wheel
d
What should be done to prevent the compressor in a cooling system from starting and stopping too frequently? Choose one answer. a. Start and stop the compressor with a setpoint thermostat b. Turn off the compressor when temperatures required for conditioning are reached c. Run the compressor continuously and vent any excess cold air d. Run the compressor continuously, and unload it when the temperature setpoint is reached e. Run the main supply air fan continuously
e
When air-handling units use hot water heating coils, energy can be saved by: Choose one answer. a. Shutting of the hot water circulating pump when the air temperature setpoint is reached b. Switching over to electric heat when the outside air temperature drops excessively c. Preheating the water with the boiler exhaust heat d. Turning off the supply air fans when the air temperature setpoint is reached e. Adjusting the water temperature setpoint according to the outside air temperature
a
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
a
Which of the following air handling systems is not suitable for providing cooling simultaneously to several distinct locations in a building? Choose one answer. a. A roof top unit b. A dual duct system c. A low velocity terminal reheat system d. A high velocity terminal reheat system e. A multi-zone system
b
Which of the following components of an air handling system is not likely to be found in a typical constant air volume system when combined with perimeter heat? Choose one answer. a. Cooling coils b. Heating coils c. An air mixing section d. Filters e. A humidifier
e
Which of the following is NOT a characteristic of a dual duct system? Choose one answer. a. It provides a constant volume air circulation rate in each zone b. It provided good control of space conditions c. It can handle many more zones than a multi-zone system d. It is easier to modify than a multi-zone system e. Humidity control is excellent
c
Which of the following is NOT an advantage of a run-around heat recovery system? Choose one answer. a. The system can be retrofitted to existing HVAC systems with relative ease b. Maintenance is relatively simple c. 100% heat recovery is possible during the coldest times of the year d. No cross-contamination of airflows occurs e. The exhaust and ventilation ductwork can be located at a distance from one another
d
Which of the following is a disadvantage of heat pipe heat recovery systems? Choose one answer. a. Heat pipes have high maintenance requirements b. Heat pipes suffer from cross-contamination of the air streams c. Heat pipes have high power consumption d. A side-by-side duct arrangement is needed e. The necessary pumps and piping are complicated and expensive to install
a
Which of the following statements about air handling units is true? a) In any system the air is mainly conditioned in the units b) The units can only heat air c) The units only circulate d) For each function there needs to be a separate air handling unit e) None of the above
e
Which of the following statements about fan coil units combined with make-up air systems is false? Choose one answer. a. The units include a disposable filter, fan and heating/cooling coil b. Ventilation is provided by a 100% outside air system c. The air handling unit includes filters, heating coil, cooling coil and supply fan d. Fan coil units are installed in each room e. The fan coil units provide humidity control
e
Which of the following statements about hydronic heat pump HVAC system is false? Choose one answer. a. The unit discharges heat to the water piping system during the cooling mode b. The water temperature must be between 15°C and 32°C c. Pipe insulation is not required as the water temperature is above the room air dewpoint d. The system can be thermally self-balancing when heat rejected by the interior zones is used by the exterior zones e. A boiler is not required during the heating season
c
Which of the following statements about multi-zone air-handling systems is true? Choose one answer. a. The cooling and heating coils are installed in-line with each another b. The hot deck and cold deck dampers open simultaneously c. When the hot deck is fully opened, the cold deck is fully closed d. These systems cannot humidify the air e. These systems do not use return air
c
Which of the following statements about run around heat recovery systems is false? Choose one answer. a. Installation costs are comparatively low b. The system is readily adaptable to retrofit applications c. Piping is not required in the system d. The exhaust and ventilation streams can be remote e. Maintenance is relatively simple
e
Which of the following statements about two-pipe arrangements is false? Choose one answer. a. The arrangement is the least costly b. Piping is connected to the boiler during winter c. Piping is connected to the chiller during summer d. The arrangement is made up of a supply and return connection to a single coil e. The system can heat and cool at the same time
d
Which of the following statements is NOT true for an induction HVAC system? Choose one answer. a. The ratio of secondary air to primary air flow is typically 4 to 1 b. The room thermostat modulates the flow of chilled or hot water to the induction unit coil c. The primary air can be heated proportionally to the outside air temperature d. The primary high-pressure air is supplied at a constant 12.5°C e. With a two-pipe system temperature control is difficult during seasonal changes
c
Which of the following statements is not true for a variable volume HVAC system with perimeter heating? Choose one answer. a. Air is supplied at a temperature of about 12.5°C b. Room temperature is controlled by the volume of air supplied c. The supply air duct pressure varies widely when heating and cooling loads vary d. The conditioned air is distributed via low or medium velocity duct work e. Zone supply air is modulated by, a variable air volume box located at each branch outlet
a
Which of these statements about hydronic heat pumps is true? Choose one answer. a. The units discharge heat to the water piping during the cooling mode b. The piping must be insulated c. The water temperature is below the dewpoint of the room air d. Condensate drains from each unit are not necessary e. The refrigeration system is cooled by Freon, such as R-12
a
Which one of the following statements about central air conditioning systems is false? Choose one answer. a. Unitary systems are able to control noise and vibration better than central systems b. All the major equipment in central systems is located in a central mechanical room in the building c. Air is conditioned in the main mechanical room and distributed by duct work d. The central system is able to utilize large central equipment with high efficiency and low initial cost e. Central systems are used in large buildings
d
Which statement about compartmental variable air volume HVAC systems is false? Choose one answer. a. Smaller air handling units are located on each floor replacing a larger central unit b. Each air handling unit is installed in a mechanical room for noise reduction, safety and appearance c. Each air handling unit has its own filter, cooling coil and supply air fan d. Each compartmental unit supplies from 15 to 100% outside air for ventilation and cooling e. A central air handling unit provides humidified air at 12.5°C for ventilation to each floor
c
While addressing the building function factors of an HVAC system, a designer considers Choose one answer. a. operating costs b. operation staff's prior experience and familiarity with the HVAC system c. normal occupancy periods d. maintenance requirements e. capital costs
a
With regard to air conditioning, an induction system gets its name from Choose one answer. a. The way air in the room is mixed with the supply air b. The type of fan coils used c. The type of air handling unit used d. The air used in the central element of the system e. The volume of air conditioned
