Heater
The heater is powered by the engine cooling system, transferring the heat generated during the operation of the hotel's engine to the car interior.
Air conditioning system
1. Compressor. 2. Condenser. 3. Receiver-drier. 4. Pressure sensor. 5. Reducer. 6. Evaporator. 7. Interior electric fan. 8. Electric fan of the engine cooling system. 9. Radiator of the engine cooling system. 10. High pressure refrigerant. 11. Low pressure steam. 12. High pressure steam. 13. Pressure sensor. 14. Salon. 15. Engine compartment. 16. Outside air. 17. To the air distribution unit. 18. Front shield. 19. Outdoor or recirculated air. 20. High pressure valve. 21. Low pressure valve.
The task of the air conditioning system is to absorb heat from the air inside the car. For this purpose, a certain liquid is used in the air conditioner (known as coolant), capable of being cooled (lower the temperature) and change the aggregate state (change from liquid to gas) expanding with a large pressure drop. Therefore, the refrigerant is able to absorb heat from the environment. When the temperature rises, the pressure of the refrigerant increases, while it again passes from a gaseous state to a liquid one and condenses.
In this regard, the first task is to dilute the gaseous refrigerant, which can only be achieved by bringing it to a temperature below evaporation (or boil), which for the refrigerant Rl34a at atmospheric pressure is -26°C.
In order to achieve dilution of the refrigerant at room temperature, which, moreover, in our case can be quite high (in the engine compartment), it is necessary to increase the evaporation point of the refrigerant so that it remains in a liquid state until it is necessary to specifically cause it to expand to obtain the desired effect.
To raise the boiling point, the pressure must be increased while the temperature is lowered, and this requires the expenditure of a certain amount of energy. This energy produced by the A/C compressor is subtracted from the energy produced by the car's engine.
The principle of operation of the air conditioning system can be represented as the following phases:
- The refrigerant gas R134a is supplied to the air conditioner compressor at a pressure of 0.5 ~ 2.0 bar and compressed to 10 ~ 17 bar. The boiling point under these conditions is 60°C.
- The liquid refrigerant is heated at the compression stage to a temperature of 80~100°C, remaining in the compressor in a gaseous state. Then, being exposed to a stream of cooling air (produced by a moving car or a condenser fan), the refrigerant begins to condense, turning into a liquid state under high pressure. The refrigerant then passes through a filter that performs three functions: trapping impurities, absorbing moisture contained in the air conditioning circuit, and also acting as a reserve tank for storing existing refrigerant.
- The refrigerant reaches the expansion valve where it is injected into the evaporator at a pressure of 1.52 bar. At this pressure, the liquid/saturated vapors of the refrigerant are in equilibrium at a temperature of -7°C. At the same time, the air passing through the evaporator (under the action of a fan), being at a much higher temperature than the refrigerant, heats it to the boiling point and completely evaporates, giving off heat. When the air is cooled, the moisture it contains is collected on the evaporator in the form of drops of condensate, which are then collected in a chamber for further draining from the car. The cooled and dehumidified air is supplied to the passenger compartment, and the refrigerant is returned from the evaporator to the compressor for re-cycle.