RV bottom air conditioner structural principle
and detailed introduction
RV bottom air conditioner is a concealed air conditioning system designed for RVs. It is installed under the car or the floor of the vehicle. It achieves efficient cooling/heating by optimizing the space layout and air circulation. Compared with traditional top-mounted air conditioners, bottom air conditioners have more advantages in low center of gravity, low noise, and high compatibility. The following is an analysis of its core technology:
Main module layout
| Module | Location and function |
| Compressor | The middle or rear part of the bottom of the car, fixed by a bracket, is responsible for refrigerant compression (mostly vortex or rotor type, low vibration design). |
| Condenser | The outside of the bottom of the car (with a protective net), forced heat dissipation by the fan, condenses the high-temperature and high-pressure gaseous refrigerant into liquid. |
| Evaporator | Under the floor of the car or the bottom of the seat, connected to the air duct, absorbs the heat in the car to achieve cooling. |
| Control system | Integrated into the dashboard or smart panel in the car, it supports multiple wind speeds, temperature settings, and energy consumption displays. |
| Air duct system | Hidden air duct (ABS material), evenly supplies air through the gap between the floor or seat to reduce the discomfort of direct blowing. |
Working principle and whole process
Refrigeration mode
Compression and heating: The compressor compresses the low-temperature and low-pressure gaseous refrigerant (such as R410A) into high-temperature and high-pressure gas (80℃~100℃).
Condensation and heat dissipation: The high-temperature gas flows through the condenser under the vehicle, and is forced to dissipate heat through the fan, liquefies and cools down to 40℃~50℃.
Throttling and pressure reduction: The liquid refrigerant is depressurized and atomized by the expansion valve, and enters the evaporator to absorb heat and gasify (the temperature drops to 5℃~10℃).
Heat absorption cycle: The evaporator absorbs the heat in the car, and transports the cold air to various areas through the air duct to complete the refrigeration cycle.
Heating mode (heat pump type)
Four-way valve switching: Reverse the refrigerant flow direction, and the evaporator and condenser functions are interchanged.
Heat absorption outside the car: Extract heat from the outside air (even in a -10℃ environment, it can still absorb heat) and release it into the car through the condenser.
Energy efficiency optimization technology
Frequency control: dynamically adjust the compressor speed according to the temperature difference (such as 30%~100%), saving 20%~40% energy.
Zoned air supply: independently control the temperature of the front and rear cabins (such as 25℃ in the driving area and 22℃ in the living area).
Comparison with roof-mounted air conditioners
| Comparison items | Bottom-mounted air conditioners | Roof-mounted air conditioners |
| Space occupancy | Hidden installation, the roof can be freely used | Occupies roof space, affecting the layout of solar panels |
| Noise | In-car noise <50dB (air duct silencer design) | In-car noise 55~65dB (body directly exposed) |
| Maintenance convenience | Need to lift the vehicle for inspection, but the filter is easy to clean | Direct roof inspection, but the condenser is easy to accumulates dust |
| Applicable models | Low-top RV, new energy RV (compatible with high-voltage system) | High-top C-type RV, traditional fuel RV |
| Cost | Higher | Lower |
