EGEE 102
Energy Conservation and Environmental Protection

How Air Conditioners Work

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Contrary to what is generally assumed, outside air is not cooled inside the air conditioner and then supplied inside. Only heat energy is moved or pumped by the air conditioner from a low temperature environment (inside the building) to a high temperature environment (outside the building).

Instructions: Place your cursor over the image below to learn how an air conditioner works.

How an Air Conditioner Works

Click here to open a text description of how an air conditioner works.

How an Air Conditioner Works

  1. The compressor in your outdoor unit compresses the refrigerant (or "Freon") by transferring the part of the electrical energy it consumes into a high-temperature, high-pressure gas.
  2. As that gas flows through the outdoor coil, it loses heat to the surroundings (because the refrigerant is at a higher temperature than the outside temperature).
  3. The cooled gas condenses from a liquid into a high temperature, high pressure liquid.
  4. This liquid refrigerant travels through copper tubing into the evaporator coil.
  5. In the evaporator coil, the refrigerant expands. Its sudden expansion turns the refrigerant into a low temperature, low pressure gas.
  6. This cool gas then absorbs heat from the air in the room which is blown over the evaporator coil.
  7. The cooled air is distributed back through your room or multiple rooms.
  8. Meanwhile, the heat absorbed by the refrigerant is carried back outside through copper tubing and released into the outside air. So only the heat is transferred to the outside, not the air.

Instructions: Press the play button to observe an animated version of how an air conditioner works.

An Animated Version of How an Air Conditioner Works

Click here to open a text description of how an air conditioner works

How an Air Conditioner Works

As described in the text above, the animation shows you the process.

The compressor in your outdoor unit compresses the refrigerant (or "Freon") by transferring the part of the electrical energy it consumes into a high-temperature, high-pressure gas. As that gas flows through the outdoor coil, it loses heat to the surroundings (because the refrigerant is at a higher temperature than the outside temperature).

The cooled gas condenses from a liquid into a high temperature, high pressure liquid. This liquid refrigerant travels through copper tubing into the evaporator coil. In the evaporator coil, the refrigerant expands. Its sudden expansion turns the refrigerant into a low temperature, low pressure gas.

This cool gas then absorbs heat from the air in the room which is blown over the evaporator coil. The cooled air is distributed back through your room or multiple rooms. Meanwhile, the heat absorbed by the refrigerant is carried back outside through copper tubing and released into the outside air. So only the heat is transferred to the outside, not the air.