Stationary air conditioning, function

W83.30-1050-12

1 Refrigerant compressor with magnetic clutch

2 Capacitor

3 Fluid reservoir with drier and inspection glass

4 Pressure switch

5 Solenoid valves

6 Expansion valve

7 Evaporator

8 Air intake openings

9 Cold reservoir

10 Noise optimized fans

11 Expansion valve

12 Check valve

A High pressure, liquid

B High pressure, gaseous

C Low pressure, gaseous

D Low pressure, liquid

General

The task of the stationary air conditioning is to cool the cab interior while the vehicle is standing, if high outside temperatures are present. In conjunction with the vehicle's air conditioning, the stationary air conditioner provides refreshing coolness in the cab in any weather, even if the engine is not running. Thus the driver has the opportunity, during breaks and waiting times (e.g., during loading and unloading, in traffic jams, etc.) to set a climate he/she perceives as pleasant.

Function

The gaseous refrigerant that is under pressure is suctioned by the refrigerant compressor (1) and pushed through the condenser (2) in coils. There, the refrigerant vapor is cooled down until it becomes liquefied and then forwarded in the fluid reservoir (3). Any contamination that might exist is absorbed and filtered out. A pressure switch (4) is located on the fluid reservoir (3) which interrupts, if the pressure drops to below approx. 2 bar, the circuit to the magnetic clutch on the refrigerant compressor (1). Thus, the refrigerant compressor (1) is immediately switched off when there is a pressure loss in the system to prevent refrigerant from escaping into the environment.

The pressure switch (4) also switches off the refrigerant compressor (1) via the magnetic clutch, if the system cannot evaporate as much refrigerant as the refrigerant compressor (1) delivers, and thus a pressure of more than 26 bar develops (e.g. when the evaporator sensor is defective).

The pressure switch (4) detects the system pressure at the output of the fluid reservoir (3) where the compressor or fan clutch is switched on or off via the switch signals.

The solenoid valves (5) either supply the liquid refrigerant to the air conditioning or the stationary air conditioner depending on the operating condition. The liquid refrigerant reaches the cold reservoir through the pressure line on the cab floor and the rear wall riser via an expansion valve (11) where it evaporates, and the cold air is blown into the vehicle interior through the noise-optimized fans (10).

In doing so, heat is extracted from the cold reservoir until the thermo switch terminates the charging process by switching the solenoid valves (5). The refrigerant that has become gaseous and charged with evaporation heat again returns to the compressor via the return line and the solenoid valve.