Air conditioning is no longer a luxury, but a basic equipment of 90% of cars sold on the European markets. This press material specifies the roles of particular elements of the air conditioning system based on the analysis of the whole refrigerant loop cycle.
The task of the air conditioning system is the reduction of the humidity and the change of the temperature of the outdoor air and its transportation to the car cabin. It is possible due to the refrigerant performing a permanent work cycle. In the whole cycle the said refrigerant changes its state a few times. Its temperature and pressure are the key parameters.
The three states of one refrigerant
Liquid, gaseous and diphasic – these are the three states of the refrigerant in the air conditioning system. In the intermediate diphasic state, the fluid is partly gaseous and partly liquid. The state of the refrigerant changes in the course of the exchanges of energy in the condenser and the evaporator, due to the work of the compressor and the expansion valve. Let’s go through the loop cycle, starting with the compressor.
- In a correctly working air conditioning system the fluid must reach the compressor in a 100% gaseous state. It is at low pressure and at low temperature. The diameter of the pipe is at its largest at this point.
- The task of the compressor is the compression of the refrigerant. Its pressure and temperature rises, but it remains in the same gaseous state.
- The next stage is the condenser, where the refrigerant gets cooled, which causes the change of its state into a liquid. Even though the temperature decreases significantly, the pressure remains high.
- The fluid then enters the receiver drier, where it is filtered and dried. The separation of water prevents the freezing of the system elements in the refrigerant expansion phase. Apart of filtration, no other important processes take place here. The temperature of the refrigerant is still low. The refrigerant is liquid and is subject to high pressure.
- The expansion valve is the next important element, which transforms the fluid from the high pressure liquid state to the low pressure diphasic state. This means that the refrigerant is partly a liquid and partly a gas. This process results in a sharp drop in temperature.
- The refrigerant transforms to a fully gaseous state in the evaporator, where the key process for the air conditioning, i.e. cooling of the air passing through the evaporator, takes place. The outdoor air not only yields its heat, but also gets dehumidified, as a result of which the water vapour accumulates and condensates on the evaporator’s walls. The refrigerant absorbs enough heat in the evaporator to change to the gaseous state. The pressure remains low. It’ll rise when the refrigerant reaches the compressor and starts the next working cycle.
Why is it worth to be a specialist in the air conditioning systems?
Repair garages that intend to develop their businesses in terms of air conditioning systems maintenance and repair have a bright future ahead. Air conditioning has become one of the basic elements of the vehicle. This means that there’s a huge potential for the segment of air conditioning maintenance, servicing and repair. It won’t be hindered even by temporary problems, e.g. refrigerant prices increase.
Proper servicing of air conditioning systems requires a professional approach, as well as knowledge – both in theory and practice. The knowledge may be acquired on trainings – which may be completed without the need to leave home. Valeo has prepared a set of online workshops, the so-called webinars, which are available upon registration free of charge.
Find out more at: valeoservice.com.
