Basic Refrigeration Flashcards
(37 cards)
What are the two most frequently used closed refrigeration systems?
-Compression system (mechanical)
-Absorption system (non mechanical)
Components of a basic compression system
-Compressor
-evaporator
-condenser
-liquid metering device
-piping
-filter drier
The basic compression refrigeration system can be divided into two sides. What are they?
-high pressure side
-low pressure side
Discharge side of the compressor, the condenser, and all interconnecting pipe up to the liquid metering device are all on what side of the system?
The high side
Discharge side of liquid metering device, evaporator, inlet side of compressor and all interconnecting pipe-connecting piping are what side of the system?
Low side
The high side of the compression refrigeration system includes components and piping subject to what kind of pressures?
At and above condensing pressure of the refrigerant
How many pressure changes and heat transfer changes does the refrigeration cycle involve?
Two
Define compressor
A machine, with or without accessories, for compressing a specific refrigerant vapour
What does an evaporator do?
Absorbs heat from the medium to be cooler
What does the condenser do?
It is the component that is designed to liquify refrigerant vapour by removing heat
Three basic types of condensers?
Air cooled
Water cooled
Evaporative
Three types of water cooled condensers?
Double tube
Shell and coil
Shell and tube
True or false. Double tube condensers are constructed with one or more water tubes contained concentrically within a larger tube. Cooling water flows through inner tubes while refrigerant flows in the opposite direction in the outer tubes?
True
What is the most frequently used liquid metering device in refrigeration and air conditioning systems?
Thermostatic expansion valve (TXV)
How does a TXV work?
It automatically regulates the amount of liquid refrigerant admitted to the evaporator coil in accordance with refrigeration load and the degree of superheat leaving the coil
How are adjustments made on systems that use an orifice in place of capillary tubes or TXV’s?
They can be removed or changed for a different size to achieve adjustments or servicing
What kind of piping is typically used for air conditioning systems? How is it sized?
ACR (air conditioning refrigeration) pipe. It is sized by an actual outside diameter. It comes in 20’ lengths of hard temper and coils of 50’ in soft temper
ACR Copper tubing is available in what two types?
Type K - thick wall- green colour code
Type L - thin wall - Blue colour code
Filter driers have directional arrows on them. What direction should those arrows point?
Towards the evaporator coil
What is evaporative cooling?
A process that occurs when a liquid changes to a vapour by absorbing heat.
Define evaporator
That part of a refrigeration system designed to produce refrigeration by vaporizing.
What is a CFC?
Chloroflourocarbon
Define Global Warming Potential
A number assigned to a compound which compares it to the effects of carbon dioxide (COz). (GWP of 1000 means a thousand times more damaging than the effects of COz.)
What is latent heat?
The amount of heat required to change the state of a substance without changing its temperature.
