How Does an Air Conditioner Work?

When we think of air conditioning, typically the first thing that comes to mind is cold air blowing out of our air vents. However, did you know the purpose of an air conditioner is not necessarily to cool the air, but actually remove heat from an area? To be specific, an air conditioner works to draw latent heat (think humidity) out of an area and replacing it with less-humid air. Now that the basics are covered, let’s get technical.

How It Works – The Technical Stuff

When an air conditioner is in cooling mode, a hot, high-pressure refrigerant will flow from the compressor and across the condenser coil - both of which are located in the outdoor unit. As the refrigerant is flowing through the condenser coil, the condenser fan will run in an effort to pull cooler air across the coil, thus expelling heat from the refrigerant. This process causes the hot vapor to condense into a hot liquid – hence the name “condenser.”

Following that process, the high-pressure liquid will flow to the metering device in the indoor unit. Once the refrigerant reaches the metering device inside the indoor unit (i.e., “air handler”), the pressure decreases and the refrigerant changes to a low-pressure refrigerant, where it then flows through the evaporator coil, as seen in the diagram. This cool, low-pressure refrigerant is ideal for absorbing heat.

From there, the blower motor draws warm, humid air out of the room and across the cool evaporator coil, which absorbs most of the latent heat and passes the less-humid, conditioned air through the evaporator coil and back into the room. As the refrigerant absorbs more heat, it evaporates into a low-pressure vapor (hence “evaporator”) and returns back to the condensing unit, where the cycle begins all over again.

Note: This is the process for a typical split system. Some systems can run in reverse when running heat, meaning the evaporator functions as the condenser and vice versa.

Overcoming Humidity Issues

A very common issue – especially in the South – is controlling humidity during the summer months. Not only is this important for comfort reasons, but individuals’ health are also dependent on proper humidity control.

Often times a system may be running at the thermostat’s set temperature, but the room still feels uncomfortably warm. This occurs because a thermostat measures sensible heat, but not latent heat. Additionally, because there is more humidity in the air during the summer months than the winter months, high humidity issues are more frequent during our warmer months. Per the EPA, the recommended indoor relative humidity level ranges from 30-50%, favoring the lower end during the summer months and the higher end during the winter months.

To remove more humidity from an area, arguably the best option is to get a dehumidifier. A few common types are the desiccant dehumidifier, a mechanical dehumidifier, and the portable dehumidifier. Which dehumidifier is best depends on how large of an area you need to control and how much humidity you need removed. A portable dehumidifier is ideal for a single room, whereas a mechanical dehumidifier would be more suited towards an entire building.

Struggling with humidity problems? We’re here to help - don’t hesitate to give us a shout!