Condenser

Types of Condensers

There are three main types of condensers: air-cooled, water-cooled, and evaporative. The main difference is how each removes the excess heat.

• Air-cooled

The refrigerant moves through the condenser's copper tubing, which is called the condenser coil. Air-cooled condensers remove heat by dispersing air over the condenser coil.

There are two types of air-cooled condensers.

• • Natural convection

  • The removal of heat is done by natural means (ex. buoyancy) in this condenser via condenser coils. When the air meets the hot condenser tubes heat is absorbed from refrigerant and the temperature of the air increases. The warm air rises, as it has a lower density, and the cold air removes the heat from the condenser. 

     

  • Forced convection

The removal of heat in this type of air-cooled condenser is implemented by having a fan or blower incorporated in the condenser to migrate air via fluid currents over the coils at a certain velocity. Fins of the condenser coils are closely spaced, about 5-7 fins/cm, which means dust or dirt can easily pile on them so keeping them clean for optimal performance.

• Water-cooled 

Water-cooled condensers use water to remove heat. These condensers are preferred wherever there is sufficient amount of clear inexpensive water and the water is easily disposable. 

There are three types of water-cooled condensers.

• • Tube-in-tube/Double tube condenser

  • In this type of condenser there is a water tube inside of a large refrigerant tube and the hot vapour refrigerant enters at the top of the condenser. The heat from the refrigerant is absorbed by water and condensed liquid refrigerant flows at the bottom. Note that the refrigerant tubes are exposed to ambient air meaning that some heat is also absorbed by said ambient air through natural convection.

  • Shell and coil condenser

  • In this type of condenser the cooling water moves through the coil causing condensation and the refrigerant, in vapor form, enters the shell.

  • Shell and tube condenser

In this type of condenser there is a cylindrical steel shell which contains many straight water tubes. These tubes expands into grooves in the tube sheet holes forming a vapor-tight fit. This tube sheet is welded to the shell at both ends and the removable water boxes are bolted to the tube sheet at each end to facilitate the cleaning of the condenser. 

• Evaporative

While these remain the least popular choice, they are used when either water supply is inadequate to operate water cooled condenser or condensation temperature is lower that can achieved by air cooled condenser. Evaporative condensers can be used inside or outside of a building and under typical conditions, operate at a low condensing temperature.

    Typically these are used in large commercial air-conditioning units. Although effective, they are not necessarily the most efficient.