Worksheetsunit 36
Total questions: 27
Worksheet time: 15mins
The total heat content of infiltrated air of the same dry-bulb temperature may vary from one part of the country to another because of the difference in ____.
solar load
sensible heat
humidity
convection currents
A homeowner plans to build a house out in Las Vegas, Nevada, in the middle of the desert. It would be in his/her best interest to lower the 'solar load,' to locate most of the windows on the ____ sides of the house.
north and east
east and west
north and south
south and west
The solar load on a structure is the heat gain resulting from the ____.
heat from the surrounding air conducted through the materials of the structure
air infiltration
heat from the radiation from the sun
dry-bulb inside the structure
More than one evaporator coil circuit is used when ____.
the evaporator is located outside the conditioned area
there would be excessive refrigerant pressure drop in the coil circuit
a distributor would not be practical
a slant coil is at an angle more than 60°
A popular material combination used in air-conditioning evaporators and condensers is ___.
copper tube-stainless steel fin
copper tube-copper fin
copper tube-aluminum fin
stainless steel tube-aluminum fin
In reciprocating compressors used in air conditioning, the motor is mainly cooled by ____.
air over the shell of the assembly
none
suction gas returning to the compressor
both
In rotary compressors, the motor is cooled by ___.
air over the shell of the assembly
discharge gas from the compressor
suction gas returning to the compressor
liquid refrigerant by-passed from the liquid line
A dirty condenser coil can lead to ___.
increased efficiency
reduced efficiency
reduced head pressure
increased subcooling
High-efficiency condensers ___.
can withstand higher pressures than standard condensers
have more surface area than standard condensers
have stainless steel coils
are located in separate cabinets
When exposed to salt air, ___ should be used for the screws to secure the sheet metal of cabinets of air conditioning equipment.
copper
stainless steel
iron
tin
The package air-conditioning system is ___ than the split system because it is completely factory assembled and charged with refrigerant.
less efficient
slightly less efficient
slightly more efficient
more efficient
On a package air-conditioning system, which refrigerant lines must be field-installed?
Discharge and suction.
Liquid and suction.
Discharge and liquid.
No lines need to be field-installed.
Appearance is a major drawback with what type of air-conditioning equipment?
Ductless split systems.
Ground level package units.
Rooftop package units.
Multi-position package units.
The air temperature of the air off an evaporative cooler is ___.
warmer than the entering air
cooler than the entering air
the same as the entering air
made up of sensible heat only
The moisture content of the air in different locations of the country must be taken into account when selecting air-conditioning equipment.
True
False
After being threaded many times, the screw holes in condenser cabinets may become oversized; if so, replace the screws with new ones of the same size.
True
False
If a structure has no attic, there should be sufficient insulation in the roof to minimize the heat gain in the occupied space.
True
False
Air-conditioning equipment will perform at its best efficiency when running at full load.
True
False
If a residential split air-conditioning system has a compressor equipped with a start capacitor and relay, it is probably using a thermostatic expansion valve as a metering device.
True
False
The supply duct portion of an air handling system needs to be insulated when run through an unconditioned space.
True
False
The return duct portion of an air handling system never needs to be insulated.
True
False
When an "A" coil is used in a horizontal application, the coil is laid on its side and a special drain pan is required.
True
False
Slant coils for downflow application are designed with a coil slant of usually ________________°.
40
45
50
Three types of expansion devices are used in residential air conditioning systems. They are TXV, capillary tube, and orifice.
True
False
There are three kinds of attic ventilation: power, natural, and (a) .
A compressor that uses a stationary vane is the (a) type.
What are the three common evaporator designs used on air conditioning equipment?
A-coil, X-coil, slant coil
Z-coil, H-coil, slant coil
A-coil, H-coil, slant coil
A-coil, K-coil, slant coil
