Two basic categories of chillers are the - answer compression cycle and absorption
The five requirements for comfort are proper temperature, humidity, filtration, and
ventilation - answer circulation
The primary function of an expansion device is to - answer produce a reduction in the
pressure on the liquid refrigerant, regulate the flow of refrigerant into the evaporator,
lower the boiling point of the refrigerant far enough below the temperature of the load to
get the needed heat transfer rate
The wet-bulb depression is - answer the difference between the dry-bulb and wet-bulb
temperatures
The dew-point temperature is the - answer temperature when the moisture begins to
condense out of the air
How many BTUs are required to change one pound of ice at 20°F to steam at 220°F? -
answer1,304 Btu/h
If an R-12 refrigeration system is operating with a 25.4 PSIG suction pressure, what is
the evaporator superheat
if the evaporator outlet temperature is 34°F? - answer9°F
On an R-11 or R-123 system, the refrigerant removal process normally starts with the
removal of - answerliquid refrigerant
The condenser in a refrigeration system - answerde-superheats the vapor from the
compressor, condenses the vapor from the compressor, sub-cools the liquid refrigerant
before it leaves the condenser
The human body gives off heat by which of the following? - answerconvection, radiation,
and conduction
If the temperature remains constant and the volume that a gas occupies increases, the
pressure will - answerdecrease
Transformers are rated using - answervolt-amperes
Measuring velocity pressure in a duct indicates the - answerspeed at which the air is
moving
, A solid material exerts a pressure or force - answerdownward only
Pure water boils at a temperature of 212°F at which of the following standard
conditions? - answer14.967 psi
Which of the following would allow a system to operate more efficiently? -
answercondenser that had refrigerant leaving with 15° of subcooling
One watt of electrical energy is equal to - answer3.413 Btu
Rotary compressors are used primarily in - answerdomestic refrigerators
The water circuit in shell and coil and coil-type tube-in-a-tube condensers must be
cleaned - answerchemically
When a water regulating valve is used to control the head pressure of a water-cooled
system, the valve's
spring is acting against which pressure to modulate the water flow? - answerhead
pressure of the system
The standard atmospheric pressure at sea level is - answer29.92" Hg
The steps to aggressively controlling the contamination of indoor air would involve -
answerlocating and eliminating the source of contamination, providing adequate
ventilation, providing methods for cleaning the air
If the resistance against a propeller fan is doubled, the cfm output decreases, but the
amperage draw of the
motor - answerincreases
Which of the following represents a different temperature than the other three? -
answer475°K
The best method of leak checking is when the refrigeration system is - answerstanding
with dry nitrogen pressure of 150 psig in the system
Technician "A" says that if the air filter on an air-conditioning system is totally blocked
with dirt, the amperage draw of the evaporator fan motor will go down. Technician "B"
says that if you close down one
supply register on a duct system, the volume of air feeding the other locations will
increase slightly. Which of the following statements is correct? - answerTechnician "A"
is correct. Technician "B" is correct
The refrigerant in a refrigeration system changes state in the - answercondenser and
evaporator
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