Air Conditioners Move Heat
All scenes › Chapter 2 Indoor unit: boiling soaks up heat
Cool air and water
Cooled air comes out, and water vapor in the air turns to water
View in 3DThe air cools, and water drips
Air that has lost its heat comes back out from the bottom of the indoor unit, now cooler. That is the cool breeze of an air conditioner. But when air touches the cold pipes, water drops form on them too. This water runs outside through a hose.
Why?Air carries water vapor you cannot see. Just as water drops form on the outside of a cold glass, water vapor turns into water when air cools below a certain temperature. Room air at 27 °C and 50% humidity starts to drip once it cools below about 16 °C, and the pipes carrying refrigerant are much colder than that.
Learn moreThat is why a room feels less sticky with the air conditioner on. In this example, about 0.9 L of water collects every hour (a rough estimate that assumes the air comes out at 14 °C). The temperature at which water starts to form is called the dew point.
- Air coming out of the indoor unit (example)
- about 14 °C
calculated from R-32 property tables (CoolProp) · example: room 27 °C, outdoors 35 °C
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More in the series
Temperatures, pressures and amounts of heat are calculated from property tables for the refrigerant R-32 (CoolProp). The example is a home air conditioner removing 2.5 kW of heat, with the room at 27 °C and the outdoors at 35 °C. In the 3D view, the refrigerant moves far slower than in real life, and the inside of the compressor and the expansion valve are shown as enlarged, simplified models.