Quiz 21

What are some typical problems on the liquid side of a liquid cooling evaporator?

- float mechanical fails - too much air in the system - mineral deposits - leaks - not all refrigerant is liquid

Low temperature food storage applications generally start at _______.

0 degrees F

As a rule of thumb, the temperature of the evaporator should be about _______ degrees F colder than the box temperature.

15

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?

25 psig

The household refrigerator fresh-food compartment typically ranges from_____.

28 to 40 degrees F

A typical evaporator operating temperature in an air-conditioning system is _________.

40 degrees F

High-temperature refrigeration applications will normally provide box temperatures of ________.

47 to 60 degrees F

A typical superheat for an evaporator operating under normal conditions would be________.

8 to 12 degrees F

Describe a flooded coil

A flooded coil is when you have a low superheat and possibly be overcharged.

_________ the air means to remove the moisture, and this is frequently desirable in refrigeration systems.

Dehumidifier

T/F: Every central split cooling system manufactured in the USA today must have a Seasonal Energy Efficiency Ratio (SEER) of at least 10.

False

What is a starved coil?

Is when you have a high superheat. Also restriction or being under charged could be present

________ -temperature refrigeration produces temperature below the freezing point of water

Low

What do temperature ranges for commercial refrigeration refer to?

Low, medium, high

__________ evaporators are used when the coil would become too long for a single circuit, percent vapor

Multiple circuit

The process of removing heat from a place where it is not wanted and transferring that heat to a place where it makes little or no difference is known as _________.

Refrigeration

_________ is the best method of checking to see when a refrigerant coil has a proper level of refrigerant.

Superheat

T/F: A stamped plate evaporator usually does not use a fan to move air across it

True

T/F: The capacity (tonnage) of heat exchanger can vary with its height and depth

True

T/F: The film factor is a relationship between the medium giving up heat and the heat-exchange surfaces.

True

T/F: The refrigeration evaporator is a component that absorbs heat from the conditioned space into the refrigeration system.

True

T/F: To check the performance of a dry-type evaporator, the service technician would first make sure that the refrigerant coil is operating with enough liquid inside.

True

What is a bearing washout?

When there's low oil level in the crankcase

Why are the fins of a low temperature evaporator spaced wider apart than those on a high temperature evaporator?

because the fins will accumulate ice. With the fins being wider it will allow the ice to form, but will not cause restriction to the coil.

The_______ of the liquid refrigerant determines the coil operating temperature

boiling temperature

If the application requires a coil design to operate below freezing, there must be provision for_________.

defrost

A direct expansion-type evaporator is also called a ________.

dry-type evaporator

The _______ in a refrigeration system is responsible for absorbing heat into the system from whatever medium is to be cooled.

evaporator

The boiling temperature and its relationship to the system exist in the _______.

evaporator

Evaporators that are operated full of liquid and are equipped with a device to keep the liquid refrigerant from passing to the compressor are known as ________.

flooded evaporators

A refrigeration system designed for the storage of flowers or candy is considered a _______ type.

high temperature

A defrost system that pipes the compressor discharge vapor directly to the evaporator is called a (n) ________ type.

hot gas

Define superheat.

is the best method of checking to see when a refrigerant coil has a proper level of refrigerant. Also when the refrigerant vapor is saturated with heat.

Define saturated vapor.

is when all the liquid has been boiled off into a vapor.

The household refrigerator fresh-food compartment is a good example of _______ refrigeration.

medium-temperature

When the refrigerant vapor is saturated with heat it is known as a(n) _______.

saturated vapor

SEER is calculated based on the total amount of cooling the system will provide over the entire season, divided by the total number of ____________ it will consume.

watt hours