Cooling

Here’s What Makes It Cool

An air conditioner includes a compressor, fan, condenser coil, evaporator coil and refrigerant. The system removes heat from indoor air and transfers it outside, leaving the cooled indoor air to be recirculated. A central air conditioning system uses electricity as its power source.

Most people think that air conditioners lower the temperature in their homes simply by pumping cool air in. What’s really happening is the warm air from your house is being removed and cycled back in as cooler air. This cycle continues until your thermostat reaches the desired temperature.

An air conditioner is basically a refrigerator without the insulated box. It uses the evaporation of a refrigerant to provide cooling. The mechanics of the refrigerant evaporation cycle are the same in a refrigerator as in an air conditioner.

This is how the evaporation cycle in an air conditioner works:

  1. The compressor compresses cool refrigerant gas, causing it to become hot, high-pressure refrigerant gas (red in the diagram).
  2. This hot gas runs through a set of coils so it can dissipate its heat, and it condenses into a liquid.
  3. The refrigerant liquid runs through an expansion valve, and in the process it evaporates to become cold, low-pressure refrigerant gas (light blue in the diagram).
  4. This cold gas runs through a set of coils that allow the gas to absorb heat and cool down the air inside the building.

Mixed in with the refrigerant is a small amount of lightweight oil. This oil lubricates the compressor.

Air conditioners help clean your home’s air as well. Most indoor units have filters that catch dust, pollen, mold spores and other allergens as well as smoke and everyday dirt found in the air. Most air conditioners also function as dehumidifiers. They take excess water from the air and use it to help cool the unit before getting rid of the water through a hose to the outside. Other units use the condensed moisture to improve efficiency by routing the cooled water back into the system to be reused.

The basic components of an air conditioning system are:

  • A Condensing Unit (the outdoor section)
  • A matching indoor air handler or furnace with coil
  • Ductwork to transfer the cooled air throughout the home