HVACR UNIT 12
The line that connects the compressor to the condenser is called the:
Discharge line.
In the compression refrigeration cycle, the refrigerant is superheated:
Leaving the evaporator, through the compressor, up to the condenser.
The refrigerant is a high-pressure, warm, subcooled liquid at the inlet of the metering device. The state of the refrigerant is:
100 percent liquid.
A compressor that uses a high-speed impeller to throw the refrigerant outwards is called a:
Centrifugal compressor.
The order of the four main components of the refrigeration cycle is:
Compressor - condenser - metering device - evaporator.
The four major components of the compression refrigeration cycle in order are:
Compressor, condenser, metering device, evaporator.
Optional components on the high side of a refrigeration system include:
Discharge line muffler, oil separator, liquid receiver, and liquid line filter-drier.
The two large classes of metering devices are:
Fixed restrictions and thermostatic expansion valves.
In the compression refrigeration cycle, the refrigerant is saturated:
In the evaporator and condenser.
At what point in the refrigeration cycle does the refrigerant lose the most heat?
In the middle of the condenser where it changes from a gas to a liquid
At what point in the refrigeration cycle does the refrigerant absorb the most heat?
In the middle of the evaporator where the cold liquid turns to a cold gas
In the compression refrigeration cycle, the refrigerant is subcooled:
Leaving the condenser up to the metering device.
Where is the liquid receiver located?
On the high side just after the condenser
Where is the suction accumulator located?
On the low side just before the compressor
The difference between a liquid receiver and a suction accumulator is that:
Receivers only allow liquid to leave while accumulators only allow vapor to leave.
A compressor that squeezes gas between the piston and a valve plate at the top of the cylinder is called a:
Reciprocating compressor.
What components in a compression refrigeration system maintain the pressure difference in the system?
The compressor and the metering device
Which of the two refrigerant lines going to the compressor is larger?
The low-pressure suction line
What happens to the refrigerant on the low-pressure side of a compression cycle refrigeration system?
The refrigerant evaporates at a low pressure and temperature.
The most efficient operation is achieved with:
Thermostatic expansion valves.
A forced-draft air-cooled condenser:
Uses a fan to blow air across the condenser coil.
Where is subcooled refrigerant found?
Where the refrigerant is a liquid
On an R-410A air conditioning system, the refrigerant leaving the ________ is 118 psig, 50°F, 100 percent superheated gas.
evaporator
The ________ is a device for absorbing heat into the refrigeration system.
evaporator
The refrigerant leaves the ________ as a low-pressure, low-temperature, superheated vapor and returns to the compressor.
evaporator
The refrigeration cycle is made possible by the ________ difference, which is maintained by the compressor and metering device.
pressure
The temperature of the liquid refrigerant is reduced as heat continues to be expelled to the surrounding air. This portion of the condenser is called the ________ section.
subcooling
Compared to the condenser coils in older systems, the condenser coils in new higher-efficiency systems:
Are physically larger than older lower-efficiency coils.
The line that connects the condenser to the metering device is called the:
Liquid line.
The small line on a split system air-conditioning unit is the:
Liquid line.
The discharge, liquid, and suction lines of a packaged unit are:
Located inside the unit.
Which component of the refrigeration cycle controls the flow of refrigerant to the evaporator? It also separates the high- and low-pressure sides of the system.
Metering device
A compressor that uses a roller that rotates in an orbital motion to squeeze gas between the roller and a spring-loaded vane is called a:
Rotary compressor.
A compressor that squeezes gas between two rotating screws shaped like augers is called a:
Screw compressor.
Why does the compression refrigeration cycle have a high-pressure side?
So the refrigerant can condense at a high pressure and temperature
The two refrigerant lines connecting the inside and outside units of a split system air conditioner are:
Suction line and liquid line.
Optional components found on the low side of a refrigeration system include:
Suction line filter, accumulator, and evaporator pressure regulator.
The line that connects the evaporator to the compressor is called the:
Suction line.
________ ensures that no liquid slugs will reach the compressor and cause damage to the valves and pistons. The state of the refrigerant is 100% gas.
Superheating
