What Is Air Conditioning?

If we look for air conditioning in Collins English Dictionary, it states:

“A system for controlling the temperature and humidity of the air in a building.”

Controlling the temperature is being able to heat and cool. Not only cool.

The air that we breathe is made up of 3 major components all capable of carrying energy (heat):

  1. The component molecular constituents of air: Oxygen (23%), Nitrogen (76%), Carbon Dioxide (1%) and Inert Gases (1%)
  2. Moisture or Water Vapour: Water vapour is present in the air at all times, the quantity present being dependent upon the air temperature. The higher the air temperature the higher the water vapour (quantity).
  3. Airborne Particulate: These are the suspended impurities within the air from either industrial or natural pollution such as pollen, dust, smoke, germs etc.

As air is the only media that encompasses the whole of our body, we need to condition this air to provide comfort. The action we need to take is:

  1. Control Temperature (heating & cooling) which entails adding energy (heating) or removing unwanted energy (cooling). General comfort conditions range between 20 - 25℃ in the UK.
  2. Control Humidity (moisture content in the air), either humidify (add moisture) when dry, which can result in dryness of skin, dry throat and encourages static build-up) or de-humidify (remove moisture) when the amount of moisture in the air is high, which can result in breathing discomfort. Comfort humidity is generally between 30-70 % RH (Relative Humidity) for the UK.
  3. Provide Ventilation to provide the necessary oxygen for breathing and dispelling carbon dioxide, odour, dust, smoke etc. General ventilation requirement ranges between 5 - 18 litres per second per person.
  4. Provide Filtration to clean outside and inside air by removing dust, pollen, etc. Dust in dry air combined with dryness (lack of moisture in the air) is the main cause of static shocks. Lack of ventilation and filtration combined with the lack of maintenance is the main causes of Sick Building Syndrome (SBS).

Therefore air conditioning encompasses:

HEATING, COOLING, HUMIDITY CONTROL, VENTILATION, FILTRATION