REF UNIT 3 Flashcards
(3.1) What is the normal temperature for a low-temp application?
0 degrees Fahrenheit
(3.1) What is the normal temperature for a medium-temp application?
35 to 45 degrees Fahrenheit
(3.1) What is the normal temperature for a high-temp application?
68 to 80 degrees Fahrenheit
(3.3) How many BTUs is one ton of refrigeration?
12,000 BTUs/hour
(3.7) What percentage of the way through the evaporator is the refrigerant 100% saturated vapor?
90%
(3.8) In what systems are rotary compressors usually found?
small systems like window air conditioners and small refrigerators.
(3.8) In what systems are scroll compressors usually found?
In new residential and light-commercial air conditioning systems.
(3.9) What are the 3 jobs the condenser does?
de-super heat, condense, subcool.
(3.14) How does an ultrasonic leak detector work?
It listens for leaks.
(3.14) How does halide torch leak detector work?
refrigerant in the atmosphere will turn flame green as copper is in its presence.
(3.14) How does an ultraviolet leak detector work?
detects the dye added to the refrigerant.
(3.20) Define enthalpy
The amount of heat a substance contains (expressed in BTUs/lb)
(3.20) What does the top of the saturation curve represent?
the refrigerant’s critical temperature or critical pressure (the point where the refrigerant will not condense with added pressure).
(3.20) What do the constant lines of quality on an enthalpy chart represent?
The ratio of vapor to water that the refrigerant is at.
(3.20) What do the green lines in this enthalpy chart represent?
constant lines of entropy
(3.20) What do the pink lines in this enthalpy chart represent?
lines of constant volume
