RVs are humid in the rainy season, and air conditioning plays a big role
How does the air conditioner dehumidify while cooling/heating?
Air conditioners can dehumidify while cooling, mainly due to their working principle. When the air conditioner is turned on in cooling mode, the surface temperature of the indoor unit's evaporator (usually a cooling coil) will be lower than the dew point temperature of the indoor air. When the water vapor in the air encounters the cold evaporator, it condenses into water droplets, a process called condensation, thereby removing moisture from the air. As the water droplets increase, they flow down and are collected and discharged outdoors, thus reducing the humidity in the room.
Specifically, when air passes through the air conditioner, the water vapor condenses when it encounters cold, and the air temperature drops, but because the water content decreases, its relative humidity also decreases. This process is an isenthalpic cooling process, that is, the total heat of the air remains unchanged. Still, part of the heat is used to condense water vapor, so although the air temperature is reduced, due to the release of latent heat, the perceived temperature of the air may not drop significantly.
The principle of air conditioning during heating is different from that of cooling and dehumidification, and is relatively "simple and crude": when the temperature inside the RV rises, all the moisture in the environment will evaporate faster, and the evaporated water vapor will circulate through the air conditioner and flow out of the space with the hot air, and the humidity will naturally drop.
As mentioned earlier, excessive humidity in the RV will also reduce the cooling/heating efficiency of the air conditioner. Here we need to introduce the "latent heat load". The humidity of the living space often depends on water vapor and small water droplets floating in the air. When the temperature changes, small water droplets will evaporate into water vapor or water vapor will liquefy into small water droplets. This change in the state of water must be accompanied by the release and absorption of energy. When the air conditioner is heating, the small water droplets in the air will evaporate into water vapor as the temperature rises. In this process, the energy heated by the air conditioner is not used to change the temperature of the air, but to change the state of the small water droplets, which causes a certain degree of energy waste relative to the purpose of heating when we turn on the air conditioner. Therefore, if the humidity in the RV is reduced, the speed of temperature control by the air conditioner will also be faster.
