Filtration
Done to exclude dust particles, ash, chemical soot, and other micro organisms from the incoming air. This is done to attain a relatively clean supply of air.
Types of filters employed
- Viscous type filters
- Dry filter
- Spray washers
- Electric precipitators
Heating
Heating of air is necessary in the winters, so as to compensate the heat loss from the room. Preheating of incoming air can be achieved by the use of warm air furnaces or coils with circulating hot water or steam.
Cooling
This function is necessary in the summer. Types of cooling systems
- Direct expansion system (uses the principle of mechanical refrigeration)
- Chilled water system ( in this system a secondary medium like water is used to chill the air)
Humidification
This is nothing but the mere addition of water and becomes necessary on the winter seasons. Air in the winters has low humidity die to low temperatures. This is done by allowing the incoming air to pass over pans of water. This can also be achieved by the usage of spray humidifiers. Excess humidification should be avoided as it results in the condensation of moisture over various surfaces in the rooms.
Dehumidification
In this process water is extracted from the incoming air. This process in generally necessary in the summer and the monsoon seasons. This process can be achieved by the usage of condensation and desiccation.
Air Circulation or Distribution
This is one of the most essential parts of the air conditioning systems. It is the most important requirement and can be carried out by a variety of methods such as
- Air pumps
- Air delivery system consisting of supply and return ducts
- Air distribution system consisting of inlets and outlets
