Air conditioning in Washington DC on a hot day is a precious commodity, but modern technology has made it as basic in our lives as a part of most homes, businesses and the places we visit. Often taken for granted, the process of air conditioning has many components that combine to give us peace of mind and a good night’s sleep.
Air Conditioning 101
Utilizing a process of rapid evaporation and condensation, air conditioning is a process which involves the rapid evaporation and condensation of chemicals called refrigerants. These are compounds that have properties allowing them to change from gas to liquid and back again at low temperatures.
When evaporating into a gaseous state, the refrigerant absorbs heat. Compressed tightly together again, it condenses back into liquid, releasing that heat in the form of condensation which can be evacuated to the outdoors. Air is blown over the cooled liquid in the circulating system and distributed to the rooms through a system of duct works.
Round and Round
The refrigerant circulates through a closed loop system and maintains a delicate balance of pressure to compel its transformations. There are four components to the system:
- the compressor
- the condensing coil
- the expansion valve, and
- the evaporator coil
Starting with a compressor, the molecules are packed together tightly, creating and absorbing heat and becoming liquid. The heated liquid enters the condenser coils, a series of delicate fins which allow the heat to dissipate to the outside.
The expansion valve controls the amount of liquid entering the evaporator coils. If too much refrigerant is allowed at once, the system “floods” and is too dense to evaporate. If there is too little, it idles inefficiently.
The evaporator coils are similar to the condensing coils with a series of fins, only these absorb heat from the conditioned space as the expanding refrigerant returns to gas and heads towards the compressor.
Inside and Out
Unlike the closed loop refrigerant system which is all about containment and control, the distribution system is about sending the heated and cooled air in different directions. Employing two fans and extensive duct work, the heat is absorbed at one point and released to the outside at another.
Warm air from the conditioned space is blown over the evaporating coil where the heat which is needed to fill the expanding spaces between molecules gets absorbed by the gas. The same blower that draws the heated air blows the cooled air back into the home, office or business.
Along the condensing coils, during the process of returning to liquid, the heat is released and blown to the outdoors by a second fan.