Flashcards in Refrigeration Deck (205)
The condenser in a refrigeration system ____.
a. Desuperheat the vapor
b. Condenses the vapor from the compressor
c. Subcools the liquid refrigerant before it leaves the condenser
d. All of above
A normally operating water cooled condenser is operating with a 10 F differentail between water in and water out. If scale forms on the water tubes and the entering water is 85 F, which of the following is possible?
a. The outlet water temperature will be lower than expected
b. The system head pressure will rise
c. The water regulating valve will close
d. Both a and b are correct
In a water cooled condenser with dirty condenser tubes, the temperature difference between the refrigerant and the leaving water will be ____ when the tubes are clean.
a. Less than
b. Greater than
c. The same as
d. Slightly lower than
The shell and tube condenser is cleaned
a. With a brush after removing the end caps
b. Only with chemicals
c. With compressed air
d. With a vacuum cleaner
What can be used to maintain the head pressure of a system with a water cooled condeser?
a. Fan cycling
b. Dampers or louvers
c. Water regulating valve
d. All of the above
The typical design temperature for the water entering a recirculating water system condenser is 85 F, and most systems have a ______ rise across the condenser.
a. 1 F
b. 5 F
c. 10 F
d. 15 F
An air cooled condenser that is operating in a climate that has four distinct seasons must ______.
a. Have some type of head pressure control
b. Use a water regulating valve
c. Have a multi circuit evaporator
d. Operate with zero degrees of subcooling
T/F If the spring pressure of the water regulating valve is increased, the system head pressure will also increase.
T/F High head pressure from low ambient can cause insufficient refrigerant flow rates through metering devices, which in turn can starve evaporators.
T/F Low suction pressures, iced coils, short cycling, and inefficient cooling, can also result from low head pressures.
T/F Hard starting may also occur in a low ambient conditon, causing low head pressures.
The heat in the vicinity of the ________ gas has a tendency to cause any minerals in the water to deposit onto the tubes surface.
An evaporative condenser uses air and _______ to desuperheat, condense, and subcool the refrigerant.
If an air cooled condenser's fan motor stops running, the head pressure will _____.
In order for a flooded condenser type head pressure control system to operate, a device called a ________ holds the extra refrigerant in warmer weather when the condenser doesn't need to be flooded.
The process of removing heat from aplace where it is not wanted and transferring that heat to a place where it makes little or no difference is known as
d. Temperature balancing
The household refrigerator fresh food compartment is a good example of ______ refrigeration.
a. Low temperature
b. Medium temperature
c. High temperature
d. Average temperature
The household refrigerator fresh food compartment typically ranges from
a. 25 F to 35 F
b. 28 F to 40 F
c. 30 F to 42 F
d. 32 F to 45 F
Low temperature food storage applications generally start at
a. -20 F
b. 0 F
c. 32 F
d. 40 F
High temperature refrigeration applications will normally provide box temperature of ______.
a. 20 to 40 F
b. 32 to 50 F
c. 47 to 60 F
d. 50 to 67 F
A refrigeration system designed for the storage of flowers or candy is considered a _____ type.
a. High temperature
b. Medium temperature
c. Low temperature
d. Sharp freezing
The ______ in a refrigeration system is responsible for absorbing heat into the system from whatever medium is to be cooled.
The boiling temperature and its relationship to the system exist in the ____.
A typical evaporator operating temperature in an air conditioning system is _____.
a. 40 F
b. 55 F
c. 75 F
d. 200 F
The ______ of the liquid refrigerant determines the coil operating temperature.
a. Freezing point
b. Melting point
c. Transition temperature
d. Boiling temperature
If an evaporator has a pressure drop of 10 psig and the low side pressure is 15 psig, what is the pressure at the inlet of the evaporator?
a. 5 psig
b. 10 psig
c. 15 psig
d. 25 psig
Evaporators that operated full of liquid and are equipped with a device to keep the liquid refrigerant from passing to the compressor are known as ______.
a. Locked evaporator
b. Seized evaporators
c. Flooded evaporatos
d. Stoned evaporator
A direct expansion type evaporator is also called a _____.
a. Flooded evaporator
b. Dry type evaporator
c. Multi circuit evaporator
d. Stamped evaporator
______ is the best method of checking to see when a refrigerant coil has a proper level of refrigerant.
a. Boiling temperature
c. Dry heat
d. Vapor temperature