The compressor is the propelling element for the refrigerant in the A/C system. A compressor circulates the refrigerant in the system and it acts as the heart of A/C. It also raises the pressure and then the temperature of the gaseous refrigerant, coming from the evaporator at low pressure and temperature. The compressor moves the refrigerant from evaporator, through the condenser via a receiver and expansion valve, right back to the evaporator.
Compressors used in the automotive A/C systems must be compact in dimension and lightweight in order to allow easy installation when the available space is limited and so as to overload the relative vehicle's suspension.
The condenser is the heat exchanger which is used to subtract the heat absorbed in the evaporator, from the refrigerant circulating inside the A/C system.
The pipes of the air conditioning system allow the circulation through the different components to assure proper functioning under all operating conditions. The hoses are manufactured in conformity with the international standards and SAE .The hoses consist of a section of flexible parts, with corresponding fittings crimped at the ends.
The Inner layer resists the penetration action of the gas and has high chemical and mechanical stability from —30° to 120 °C.
The fittings at the end of the hoses are of different configurations, depending on the coupling between the hose element and the component. These fittings have flare, O-ring and quick connection couplings.
The fittings can be mounted easily and quickly and do not jeopardize the sealing.
The receiver dryer acts as a sort of reservoir for the refrigerant, and dehumidifier (drier) of the refrigerant. Normally, it has got a safety pressure pressure control (Manostat) and a sight glass mounted on the top. This sight glass allows us to check for adequate gas in the system.
Pressure Control (Monostat)
Pressure Control is an electro mechanic device that, in the configuration more commonly adopted for the A/C system, they are commonly called Manostat, has the function of:
Protecting other components from anomalous pressure values;
Regulating condensation pressure
These functions belong to the three-function or "tri-nary" pressure control.
They are divided into three main:
1) Low pressure control
2) High pressure control
3) Three functions pressure control
The other main part of the system is the evaporator unit. It is the A/C system component that has the function of removing heat from air injected into the cabin. Another very important function performed by the evaporator is that of dehumidifying the conditioned air.
The evaporator is in front of a fan. The fan pulls out the hot, humid air of the car's cabin. The refrigerant makes the hot air's moisture condense into drops of water, removing the heat from the air. Once water is removed, the "cool" air is sent back inside the car. The system has two built in switches, one that stops the compressor if the pressure is too low, and one that prevents ice from forming on the cold evaporator, as both of these faults can damage the system.
The expansion valve determines the correct amount of refrigerant going into the evaporator from the condenser through the filter, and it lowers the pressure of the refrigerant drastically. When the compressor starts, the expansion valve opens and the liquid refrigerant flows through a strainer in the high-pressure liquid inlet once in the expansion valve, the refrigerant is properly pressurized.
As the evaporator calls for more refrigerants, the expansion valve allows the required amount of low-pressure liquid refrigerant into the coils. The expansion valve maintains the delicate balance between the heat load and the cooling efficiency of the evaporator.
To switch on and off the various A/C system functions and related units, different type of switches are used and it usually has an LED that showed the switch on or off.
In addition, in some of the new cars this part has been removed from the A/C system.
And air conditioning system automatically will be turn on when the vehicle is started.
The wire harness performance is transmission data and electrification to the parts of the air conditioning system.
In addition, in some of the new cars all of the commands and data have been transmitted by ECU (Electronic Control Unit) and main wire harness of the vehicle.
It can be installed on the condenser or on the radiator. When the electric fan is mounted on the condenser, it is mounted towards the vehicle front and works in « thrust »; that is, it sucks air from the outside and thrusts it towards the condenser. If it is, however, mounted towards the engine compartment, it works in « suction ». That is, it sucks air from the outside through the condenser. If the electric fan is installed on the radiator, it is always mounted towards the engine compartment, normally adjacent to the engine fan and works in suction.
The operation of the electric fan varies according to its applications. If there is a trinary pressure switch in the system, the electric fan is switched on or off, as controlled by the pressure in the high pressure part. In other cases, the fan runs continuously starting when the air conditioner system is switched on. In some cases the condenser fan is controlled by thermistor, which switches the engine fan on and off; thus both fans operate simultaneously.