TPC 434 Flashcards
(25 cards)
The function of an evaporator is to ______ heat (from/to) the ______.
Remove; material being cooled
The capacity of an evaporator is affected by the:
Cleanliness of the evaporator
Basic evaporator configurations depend on whether they have one or more tubes and whether or not they have:
Extended surface areas
Multiple-circuit evaporators have headers or distributors that direct refrigerant to each coil from ________ expansion valve(s).
One
A comfort cooler __________ the humidity of moist air by cooling the air to a temperature __________ the dew point.
Reduces; below
Unlike a dry-expansion evaporator, refrigerant in a flooded evaporator enters as ______ liquid and exits as ______ vapor.
All; Part
In a secondary-refrigeration system, the refrigerant removes heat from the material to be cooled. This refrigerant then transfers heat to the ______ refrigerant. In the process, the ______ refrigerant boils.
Secondary; primary
A eutectic solution is a brine in which the concentration of salt is precisely set to achieve the lowest possible:
Freezing point
Which evaporator arrangement offers the greatest flexibility?
Two evaporators in parallel, each with its own expansion valve
A cascade refrigeration system has more than one:
Compressor, evaporator, condenser, and refrigerant
The basic law(s) of thermodynamics that apply to refrigeration state that:
Heat flows from a warmer substance to a cooler substance
Using a heat exchanger to lower the temperature in the liquid line and raise the temperature in the suction line has the advantage(s) of reducing:
The amount of liquid refrigerant entering the compressor
The amount of oil entering an evaporator can be reduced by using a(n):
Oil separator
If the fluid being cooled by an evaporator circulates through the coil rather that moving slowly or not at all, the performance of the evaporator improves because of the:
Increased temperature difference across the wall of the evaporator
An evaporator can be defrosted by:
Reversing the flow of refrigerant
To remove rust, scale, and sludge from a shell-and-tube evaporator you should use a(n) ______, as necessary.
Brush
A water coil can be winterized by draining out the water and:
Leaving the coil dry for the winter
Frost buildup on an evaporator coil is increased by _______ airflow and ___________ air.
Low; humid
Bent fins reduce the cooling capacity of an evaporator, because they ______.
Reduce the area exposed to the air
The purpose of the metering device in a refrigeration system is to:
Control the flow of refrigerant into the evaporator
The operation of an AXV is controlled by the:
Pressure in the evaporator
In controlling the flow of refrigerant into a flooded evaporator, the float of a high-side float valve is located [at/on] the:
High-pressure side of the valve port
If floodback occurs in a system using an AXV, a likely cause is:
Ice on the spring chamber above the diaphragm
A common problem with TXVs is ice in the valve port. The proper way to correct this problem is to ______.
Replace the filter-drier
