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Core Components of Bus Air Conditioning and Their Functions
March 28,2025
1. Compressor
Function: The "heart" of bus air conditioning system, compressing low-temperature and low-pressure gaseous refrigerant into high-temperature and high-pressure gas to provide power for the refrigeration cycle.
Type: Common types include scroll, piston or screw compressors.
Criticality: The efficiency of the compressor directly affects the refrigeration capacity and energy consumption.
2. Condenser
Function: Cool and condense the high-temperature and high-pressure gaseous refrigerant into liquid, releasing heat to the outside environment.
Structure: Usually aluminum finned tubes, with fans for forced heat dissipation.
Related components: Works with the condensing fan, and the heat dissipation efficiency affects the system performance.
3. Evaporator
Function: Liquid refrigerant evaporates here to absorb heat and cool the air in the car (blown across the evaporator surface by the fan).
Location: Installed in the air box in the car, directly determines the air supply temperature.
Additional function: Some models also have dehumidification function.
4. Expansion valve (or throttling device)
Function: Control the refrigerant flow and reduce the pressure, so that the liquid refrigerant is atomized into a low-temperature and low-pressure state and enters the evaporator.
Type: Thermal expansion valve (TXV) or electronic expansion valve (EXV), the latter has higher accuracy.
Regulation mechanism: Automatically adjust the opening according to the evaporator outlet temperature.
5. Liquid storage dryer/gas-liquid separator
Liquid storage dryer (for expansion valve system):
Stores excess refrigerant, filters impurities, and absorbs moisture (to prevent ice blockage or corrosion).
Gas-liquid separator (for throttling tube system):
Ensures that only gaseous refrigerant enters the compressor to avoid liquid shock damage.
6. Control system (ECU, sensor, operation panel)
ECU: Automatically adjusts the compressor operation according to temperature setting, ambient temperature, vehicle load, etc.
Sensor: Monitors evaporator/condenser temperature, pressure, vehicle internal and external temperature, etc.
Operation panel: For passengers or drivers to adjust temperature, air volume, mode (cooling/heating/ventilation).
7. Condenser fan and evaporator fan
Condenser fan: Forced cooling of the condenser (mostly electric or engine driven).
Evaporator fan: Blows the air in the car through the evaporator (forming cold air) or heater (warm air), with adjustable air volume.
8. Refrigerant
Function: Circulating medium (such as R134a, R407C, R410A or environmentally friendly R1234yf), transfers heat through phase change (gas ↔ liquid).
Requirement: The filling amount needs to be checked regularly, and leakage will cause performance degradation.
9. Heating system (optional, for air conditioning)
Independent fuel heater: Common in diesel buses, burning fuel to heat the coolant, and heating through the heater core.
Electric heater (new energy bus): PTC heater directly heats the air.
10. Pipes and valves
High-pressure/low-pressure pipelines: Connect various components, need to be pressure-resistant and leak-proof.
Solenoid valve: Control the on and off of the refrigerant (such as closing the refrigeration circuit in winter).
New energy buses: Electric compressors (directly driven by high-voltage batteries) may be used, and traditional belt-driven compressors are eliminated.
Battery cooling: Some models integrate the air conditioning system with battery thermal management and share the condensing circuit.
These components work together to ensure that the bus can stably provide a comfortable interior environment under complex operating conditions (such as high temperature and high load).
As a professional electric bus air conditioner manufacturer in China, CLING bus HVAC offers all kinds of bus air conditioner solutions
As a professional electric bus air conditioner manufacturer in China, CLING bus HVAC offers all kinds of bus air conditioner solutions
If you have any questions please don't hesitate to contact us.
E-mail: marketing@clingac.com
Phone: +86 18736032501
