5 Basic Components of Air Conditioning

By: Parts for Trucks 

Things are starting to heat up as we move into the summer months and that means that we’re turning down our heat and cranking up our A/C in our vehicles. Back in Parts for Trucks’ founding year, 1919, they didn’t have air conditioning in vehicles and wouldn’t for another 20 years – thankfully, we now live in a world where air conditioning is a basic feature of nearly every vehicle. 

Yet, despite it being an integral part of keeping us comfortable, many drivers don’t know how their air conditioning works.  

We’re going to lay out the five basic components of an air conditioning system for you so the next time you’re greeted with a cooling blast of air on a hot summer day, you’ll know exactly how it gets there. 


Your compressor is the starting point of your air conditioning and is, debatably, the most important part. 

At this stage, the refrigerant enters the compressor as a low-pressure gas. The compressor is usually comprised of a cylinder and piston, often driven by a belt attached to the engine. When the piston moves on a downward stroke, the gas enters the cylinder, and when it moves upwards, both the temperature and pressure of the gas rises.  

The gas, now compressed, moves on to the condenser.  


The condenser is essentially a heat exchanger, located near the front of the vehicle.  

The refrigerant enters the condenser as a high-pressure, high-temperature gas – hotter than the air or water cooling the condenser. As such, the heat flows from the gas to the cooling agent, turning the gas into a high-pressure liquid that then flows into the receiver-drier or accumulator. 

Receiver-Drier or Accumulator

Depending on the model of your vehicle, you may have a receiver-drier with a thermal expansion valve, or an accumulator with an orifice tube.  

Regardless of which you have, both act as a filter, removing moisture – using a desiccant – and contaminants from the refrigerant. They also serve as a storage unit, storing refrigerant when it’s not needed. 

Thermal Expansion Valve or Orifice Tube

Both the thermal expansion valve (TXV) and orifice tube serves as a bridge between the high and low-pressure sides of an A/C system, between the condenser and evaporator. 

The TXV is a variable control valve located at the entrance of the evaporator. It provides the pressure drop in the refrigerant and is used to maintain the evaporator temperature by the controlling the rate of flow.  

The orifice tube, a fixed-size tubing, also controls the rate of flow through a small hole in it that allows refrigerant to pass through to the evaporator. 


The evaporator, usually located within the passenger compartment, is the final step in the cycle. Due to the low pressure, the refrigerant evaporates, and absorbs heat from air recirculating in the cabin. The warm air, travelling along the evaporator coils, has its heat transferred to the refrigerant. Now cool, the air is pushed into the cabin of the vehicle, while the warm refrigerant begins the cycle again. 

If you have questions about your A/C system or its components, contact your local Parts for Trucks today. Our friendly staff will make sure your cab stays cool this summer.