Conditions for comfort, relative humidity, humidification, dehumidifying, due point control, unit of air conditioning


What is Air Conditioning?
Any type of conditioning of air which includes circulating air in a room, filtering air, cooling or heating air, humidifying or dehumidifying the air.
Complete air conditioning would mean all such processes being carried on the air.
The refrigeration plant is necessary for such an air – conditioning system.

Terminologies used in Air Conditioning

  • Psychrometry – The study and measurement of the properties of air and water vapor mixture are known as psychrometry.
  • Dry Air – Atmospheric air consisting of a mixture of gases excluding its water vapor content is known as dry air.
  • Moisture – The water vapor contained in air is called moisture.
  • Moist Air – Atmospheric air along with gases and water vapor is known as moist air.
  • Unsaturated Air – The moist air which does not contain the maximum amount of water vapor that it can hold at a given temperature is known as unsaturated air.
  • Saturated Air – The mist air which contains the maximum amount of water vapor that it can hold at a given temperature, is known as saturated air.
  • Dry Bulb Temperature (DBT) – The reading of the temperature of air given by an ordinary mercury thermometer, having its bulb dry and not under the sun or other heat-radiating objects.
  • Dew Point Temperature (DPT) – At atmospheric temperature atmospheric air always contains water in the form of vapors. If this air is cooled down, the water vapor is turned into water droplets. This temperature at which the water vapors turns into water droplets is called dew point temperature.
  • Wet Bulb Temperature (WBT) – Temperature of air indicated by a mercury thermometer whose bulb is covered by a piece of wet muslin is known as wet-bulb temperature.
  • Specific Humidity (SH) –  It is defined as the total quantity of water vapor in the moist air.
  • Relative Humidity (RH) – it is defined as the ratio of actual moist air content of a given volume at a particular temperature to the maximum amount of water vapor if the air is saturated at the same temperature.


The goal is to keep it more comfortable inside the house than it is outside.