How Do Air Conditioning Units Work?

Many of us take the cool air produced by air conditioning units for granted and never think about how the cold air is created.

The cool air distributed by an air conditioning (AC) unit offers a refreshing oasis on a hot summer day.

You find air conditioning in homes, cars, offices, on buses, and shopping centres, to name just a few locations.

AC can be a small portable unit or a huge industrial system.

Either way, it is an appliance that provides comfort and is used worldwide when temperatures rise.

But how exactly does an aircon unit transform hot air into cool air? And more importantly, how vital it is to keep the units regularly serviced and in good working order through quality replacement spares

The Parts of an A/C Unit

Air conditioners are appliances that employ a refrigeration sequence to lower the temperature of input air.

The thermodynamic method used in air conditioners is termed the vapor-compression refrigeration cycle, and the aircon mechanism comprises four parts:

  • An evaporator
  • A compressor
  • A condenser
  • An expansion Valve

Refrigerant runs through a circuit formed by these parts and is the working fluid.

A refrigerant is a composite with a boiling point below the target temperature and has a high heat of vaporisation.

It does not produce corrosion, among other characteristics.

Before the 1980s, refrigerants were usually made of chlorofluorocarbons (CFC) and different mixtures that were later found to harm the Earth’s ozone layer.

Since then, more innovative, and safer refrigerants have superseded these toxic materials.

The Air Conditioning Cycle

When a liquid refrigerant enters an evaporator, the lower pressure makes the refrigerant evaporate into a vapour.

The evaporator is open to the air in the area to be cooled (the interior of a home in the case of a wall-mounted residential AC unit).

The evaporation induces the refrigerant to draw in heat from the air through its phase change.

The vaporised refrigerant then passes into a compressor, which raises the pressure of the refrigerant.

The refrigerant then goes into the condenser, where it reverts to liquid form.

When it turns back to liquid, it discharges the heat that it absorbed inside the evaporator.

The condenser is placed in a different zone than the space being cooled (the outside of the building in the case of a wall-mounted AC unit), which allows the interior to retain the lowered temperature.

The refrigerant then moves through an expansion valve, where the pressure is lowered, and the process repeats itself.

Fans are used to move cool air out of the air-con unit into the air-conditioned area and to drain the heat from the AC unit.

The exhaust is delivered outside of the cooled space. This is why a flow of hot air can be felt if you walk past the outside element of a window-mounted air conditioning unit.

Benefits of Aircon

Air conditioning takes thermodynamic principles and implements them to make millions of people comfortable during the hot days of summer.

Exposure to excessive heat for prolonged periods is harmful, as it can cause dehydration.

This is because high temperatures lead to excessive sweating, which causes your body to lose water.

If you don’t replenish this lost water, the result is dehydration.

Since air conditioners decrease heat and therefore sweating, they help lower the risk of corporal water loss and dehydration.