What Are the Basic Components of a Commercial Air-Conditioning System?

Compressor

• Compressors form the core of commercial heating and air-conditioning systems. This component pumps refrigerant such as freon gas from the air conditioner evaporator. Compressors reduce the low pressure and volume of the refrigerant. At the same time, the mechanism changes the refrigerant into high-pressure, high-volume gas. Condensing the vapor causes the pressure and temperature of the vapor to rise. The system pumps this treated vapor to the system's condenser coils.

Condenser

• Condensers in commercial systems are mounted on the roofs of buildings. Condensers can be evaporative, earth-cooled, water-cooled or air-cooled units. Most commercial air-conditioning systems employ an air-cooled condenser. The compressor turns freon into a liquid as the condenser gathers hot vapor from the compressor. Locating the condenser on the exterior of a building allows the unit to use air to eliminate the heat absorbed by the air conditioner evaporator coil.

Metering Device

• The refrigerant flows in liquid form from the condenser to a metering device, such as a piston, capillary tube or expansion valve. Highly efficient air-conditioning systems have expansion valves. Expansion valves allow a specific volume of refrigerant to filter through depending on the capacity of the AC system. Pistons and capillary tubes permit refrigerant to flow through at the same rate regardless of the system's size. Metering mechanisms force the pressure of the refrigerant to drop, which in turn, leads to a drop in temperature. The cold refrigerant streams to the evaporator coil.

Evaporator Coil

• An evaporator coil distributes cool air throughout a building via pipes and ductwork. This component removes heat from the structure, which allows the cool air to circulate without resistance. The evaporator coil takes conditioned water vapor from the air (in cooled areas) and routes it to the drain. This process reduces the amount of relative humidity in the air. Coils require periodic inspections and maintenance to retain effectiveness. Sometimes it is necessary to replace the coils.

Air-Conditioning Filters

• Air-conditioning filters remove contaminants from the air. A clog filter lowers the operating efficiency of the cooling unit, which can lead to higher operating costs. The filters will have a rating ranging from one to 12. The higher the rating, the more pollutants -- including dust, dander, pollen and mold -- the filter has the potential to remove. Most manufacturers recommend replacement of commercial filters every 14 days.