(i) Temperature control
(ii) Humidity control
(iii) Air movement and circulation
(iv) Air filtering, cleaning and purification
The simultaneous control of these four factors within required limits when directed towards human comfort and health or when industrially directed towards conditions permitting the best product yield during manufacture and storage can rightly be called air conditioning.
The basic elements of air-conditioning systems (of whatever form) are:
1. Fans: for moving air.
2. Filters: for cleaning air, either, fresh, recirculated or both.
3. Refrigerating plant: connect d to heat exchange surface, such as finned coils or chilled water sprays.
4. Means of warming: the air, such as hot water or steam heated coils or electrical elements.
5. Means of humidification; and/or dehumidification.
6. Control system: to regulate automatically the amount of cooling or warming.