Whether you have a large central air conditioning unit for your home, a window air conditioner for your apartment, or a smaller portable air conditioner for your bedroom, air conditioning is a luxury that’s hard to live without. But how does it turn the hot air into cooled air?
While the size and brand of an air conditioning unit determine its exact function, most air conditioners rely on the same basic principles to turn warm air into cooler air. For this article, we will focus our attention to the stand-alone, single household, AC unit.
Air conditioners may seem complicated, but when you break it up into digestible pieces, the process of how your air goes from hot to cold is relatively simple. First, we need to identify the different parts of our air conditioning system and understand the primary function of each piece.
Your home air conditioning system can be broken up into three major groups; the outdoor condenser, the indoor air handler, and the ductwork/controls. Each of these significant groups has four major components that allow your air conditioning system to function correctly.
The outdoor air conditioner unit consists of these major pieces:
- The Fan – The fan cools the condenser coils and draws out heat and moisture from returning coolant.
- Condenser Coils – A condensing coil is the vehicle that sends and receives refrigerant, i.e., coolant, to and from the evaporator coil inside the house.
- Refrigerant – this is the liquid that interacts with the evaporator coil to help cool the hot air flow from your home. As it does this, it transitions from a low pressure gas to a high pressure liquid.
- Compressor – This mechanism acts as the pump, which helps to push and pull coolant through the evaporator coils.
The outdoor unit, also known as the condensing unit, is designed to endure harsh weather conditions. On the other hand, the indoor air conditioner unit is the part that’s kept inside the house. The indoor unit contains the following components:
- Blower Motor – This fan sucks warm air through the return vents in your house and then pushes that same warm air through the evaporator coil. The blower motor is also responsible for pushing cold air through the air ducts of your home and out the supply vents into each room.
- Evaporator Coils – This is where hot air mixes with cold refrigerant. The evaporator coil is responsible for removing heat and moisture from the hot that is pushed into it by the blower motor.
- Circuit Board – This is the command center which receives its orders from the thermostat, and then directs the other components to work as one integrated system.
- Filter – The filter (or air filter) traps and collects dust and other debris that may have been picked up during the cooling process.
The infrastructure, also called the living space, is home to these crucial parts of the AC unit:
- Thermostat – The brains of the operation, which gauges the temperature of the house and allows users to set the desired temperature.
- Supply Vents – The entry points for new, cool air to enter the house. Typically there is at least one supply vent in each room.
- Return Air Vents – The vents through which hot air is sucked out of the house by the blower motor. The size of the return air vent has a lot to do the efficiency and noise levels of the air conditioner. You will want to have a licensed HVAC contractor make sure your return air vent is the correct size for your home.
- Air Ducts – The large areas inside the walls of your home where the air circulates. Air flows to and from the different vents in your home through specific air ducts which keep cold and hot air separated.
Now that we understand the essential parts of our air conditioner, as well as their function, let’s look at how these pieces work with each other to create cool air. Here is a basic overview of the process works:
- Your house is too hot!
- Your thermostat, detecting the heat, sends a signal for cold air.
- The circuit board receives the signal from the thermostat and turns on the blower motor.
- The circuit board turns on the compressor and fan located in the outside unit.
- The compressor begins to pump refrigerant, i.e., coolant, through the condenser coils.
- The blower motor sucks in hot air from the living area through the return vents.
- Hot air sucked in from the house is pushed into the Evaporator Coils.
- Hot air hits the evaporator coil where it mixes with coolant from the condenser coils.
- The evaporator coil removes moisture and heat from the hot air to create new cold air.
- The blower motor pushes the new cold air through air ducts and into the living area via the supply vents.
- The used coolant is pulled from the evaporator coil through tubes back to the outdoor condenser coil.
- The outdoor fan cools the condenser coil filled with the coolant and draws out heat and moisture.
- The coolant is now ready for re-use and is sent back into the house to the evaporator coil to repeat the process.
- The cooling process repeats until your house reaches the determined temperature on the thermostat.
- Your house is now cool, and the thermostat sends a signal to the circuit board to shut the process down.
For those who may not know, Air conditioning is part of an HVAC system or Heating, Ventilation and Air Conditioning system. When it comes to air conditioning systems, regular AC unit maintenance is crucial. High humidity can negatively affect the air conditioning as it cancels out the cooling effect and may make your AC unit work harder. Due to the complexity of an Air Conditioner it is wise to rely on the help of HVAC professionals to help you service and clean your air conditioner. Without regular upkeep, the machine may fall beyond the point of repair and you may need to hire the heating and air conditioning replacement service.
Hopefully, this article has given you a better understanding of how air conditioning works and leave you with an appreciation for all that goes into beating the heat and keeping your cool.