How Does an AC System Work

July 5, 2019


A lot has changed in the 100 plus years since the invention of the first modern air conditioning system. However, today’s central air conditioners still work using many of the same basic principles. So how does a central air conditioner work?

The Science of Heat Transfer

The job of an air conditioner is to transform warm air in cool air, but it does not actually make cold air. Instead, it removes the heat and humidity from the warm air, transfers it outside, and then returns cooled air back into the house. This entire process is made possible through the science of heat transfer, refrigerant, and an air conditioner’s three main mechanical components:

  • Compressor unit
  • Condenser coil
  • Evaporator coil

Refrigerant is a special chemical that travels through the air conditioner’s tubing. As the refrigerant passes through to the compressor, it is put under pressure, which raises its temperature and converts it to gas. The gas continues to travel outdoors to the air conditioner’s condenser coil where the heat disperses across its aluminum fins.

As the heat disperses from the refrigerant in its gaseous state, its temperature drops, and it returns to its previous liquid state. The refrigerant then travels along with the tubing back indoors to the evaporator coil. This is where the liquid evaporates and cools the coil. The air conditioner’s fan then blows the warm air that is brought in from the system’s return vents. The refrigerant absorbs the heat from the warm air, and the now cool air is blown through the system’s ductwork to its air vents.

A Continuous Cycle Until Something Goes Wrong

The process of recirculating an air conditioner’s refrigerant is a continuous cycle. It continues until the air in the home reaches the temperature set on the thermostat. Of course, this process can only be successful if all the components in the HVAC system are working properly.

To ensure that your air conditioner is ready when you need it, the system requires regular yearly maintenance. In the St. Louis metro area, Scott-Lee Heating Company is the heating and cooling expert to call for all your cooling maintenance needs and repairs.