How air conditioners take hot and humid air, and make it drier and cold.
In: 36
**How does an AC make air drier?**
Before the AC blows cold air into your room from vents, ambient air gets blown through a cold *evaporator coil.* Water molecules “stick” to the evap coil through condensation and drips away. Fewer water molecules in the vent air = drier air blown into your house. This effect is the same as condensation forming around a cold glass of water.
**How does an AC make air colder?**
When a liquid boils, it absorbs energy from its environment. This is *evaporative cooling*.
If we exploit this phenomenon, how can we invent a cooling machine?
First, we find a chemical that has the right properties, such as a low boiling point. This is the *refrigerant*.
Then we cycle this refrigerant through a system composed of two parts: the *condenser* and the *evaporator.*
Long story short, the condenser is the outside part of your home split AC system: it’s the loud thing with a huge fan. The boiled refrigerant is cooled (and usually compressed, but let’s keep it simple), turning into a liquid.
The liquid state refrigerant is sent to the evaporator coil (usually in your garage or attic), and the liquid refrigerant boils off, absorbing heat in the air. Refrigerant absorbing heat = colder air, which then gets blown into your room.
Finally, the refrigerant, now in a gaseous state, is sent back to the condenser to repeat the cycle.
—
A few things to note:
1) Think of your AC not as an air cooler, but as a heat mover. The hot air in your house is simply moved outside by exploiting a physical phenomenon.
2) This evaporative cooling effect can be observed in many places. If you have ever used an air compressor, notice how the compressed air usually blows out cooler than ambient. The swamp cooler uses the same principle: cooling by evaporating water via a fan.
Latest Answers