Unit 3 Enthalpy Chart Flashcards
At what points on the graph represent the refrigerant going through the evaporator?
B - C
As refrigerant moves between points E to A, what component of the refrigeration system is the refrigerant passing through?
The condenser
What is the state of the refrigerant when it is halfway between points A & E?
(temp/pressure/liquid/vapor)
100% liquid high temp and high pressure
At what points on the graph represent refrigerant going through the compressor?
D - E
At point A, what is the state of refrigerant?
%100 percent liquid
What is happening between point C & D?
Suction line, super heated refrigerant
Desuperheats, changes vapor refrigerant to liquid refrigerant and subcools the liquid
Condenser
Centrifugal compressor
Kinetic displacement compressor
Using a vacuum pump to remove moisture within a refrigeration system.
Dehumidifying
The line that carries refrigerant from the compressor to the condenser, also known as
the hot gas line.
Discharge line
Piston, fixed bore, capillary tube and TV are examples of this component in the
refrigeration system.
Metering device
Behaves like a pure refrigerant with one boiling and condensing temperature.
Azeotropic refrigerant
12,000 btu/h
One ton of refrigerant
Absorbs heat into the system, changes liquid refrigerant to vapor and superheats the vapor.
Evaporator
Components that make up this type of compressor include pistons, connecting rods, crankshaft and wrist pins.
Reciprocating compressor
When liquid refrigerant is cooled below its condensing temperature inside the condenser.
Subcooling
The screw compressor is a positive displacement type compressor.
True
A recovery cylinder of R-134a at a temperature of 80°F has a pressure of 95 psig.
The cylinder probably contains non-condensables.
True
Refrigeration to keep fresh food from spoiling is considered high temperature refrigeration.
False
The Halide leak detector can be used to detect refrigerant leaks for all types of refrigerants.
False
A capillary tube metering device can allow more refrigerant into the evaporator when it senses a temperature rise for a hot pull down.
False
Comfort cooling is considered high temperature refrigeration.
True
When refrigerant is saturated, both liquid and vapor refrigerant can exist simultaneously.
True
Recycling refrigerant means to process the refrigerant through filters and restore the correct amount of ingredients/components to make the refrigerant like new to factory specifications.
False
The line exiting the condenser is also known as the liquid line.
True
A typical evaporator will be fed from the bottom with the vapor exiting from the top.
True
The tubing connecting the exit of the evaporator to the compressor is called the
Suction line
What are the four positive displacement compressors?
Scroll, screw, reciprocating, rotary.
How is superheat calculated?
Saturated temperature of the evaporator subtracted from the temperature at the exit of the evaporator.
Which leak detection method uses a dye injected into the system?
Ultraviolet
Met Refrigeration Effect (NRE) is expressed in Btu/lb. What does that mean?
How much heat is taken away to get the correct temperature.
Why must blended zeotropic refrigerants be charged into a system by liquid only?
Vapor can be unstable
Low temperature refrigeration systems maintain products at temperatures below __°F
0°F
