In general, a condenser is any device or machine that converts a gas to its liquid form, either through cooling or high pressures. Recall in chemistry that the change from matter’s gaseous phase to its liquid phase is known as condensation, while the opposite and reverse conversion is known as evaporation. As a corollary, a device that converts a liquid to its gaseous form is an evaporator.
A common application of condensers in everyday practice is in air conditioning units, and a study of a typical air conditioning system is enough to conceptually show most of the important processes involved in a condenser’s ability to convert gas to liquid. A condensing unit found in an air conditioning system has a series of tubes, called the heat exchanger section, where refrigerant flows. A compressor raises the pressure in the tubes and keeps the refrigerant in a liquid phase. When refrigerant flows through the heat exchanger section, it absorbs heat from the surrounding air and is converted to its gaseous state. The surrounding air then becomes cooler and is blown through the vents of the air conditioning unit. The now gaseous refrigerant then passes through the condenser and become converted to its liquid phase anew.
Condensers are also being used these days in tumble dryers. Typical tumble dryers are vented – that is, they have a hose that takes the hot, damp air from the wash and is then drained. A condenser tumble dryer doesn’t need a hose or a vent to remove the hot air. Rather, the condenser converts the hot air to a liquid form which is then collected in a water reservoir than can be removed and emptied when necessary. Consequently, condenser tumble dryers can be placed anywhere and would no longer need a hole in the wall through which a drain or a vent have to be placed.
In chemistry, a condenser is an apparatus that cools hot vapors to convert them into a liquid phase. Typical examples of laboratory condensers are the Liebig condenser, the Graham condenser and the Allihn condenser.
A Liebig condenser, composed of a straight tube surrounded by a water cooled jacket, is the simplest form of condenser that can be used. Gas flows through the tube and is subsequently cooled by the water jacket. The cooling process then converts the gas to its liquid phase. Such condensers may be found in a typical laboratory evaporator.
In contrast, a Graham condenser is composed of tubes arranged in coils, but like the Liebig, it is also surrounded by a water cooled jacket. The coils increase the surface area through which the gas may be cooled and condensed. Further increasing the surface area for condensation, an Allihn condenser has a series of large and small constriction on the inside of the tubes on top of the coils.
The last kind of condenser involves direct contact between a substances gaseous and liquid state. In a direct contact condenser, the gaseous or vapor form of the substance lose its latent heat of vaporization to transfer heat into the liquid. The liquid becomes hotter, yet maintains its liquid state, while the vapor cools and becomes converted into a liquid. In this type of condensation, the vapor and liquid forms should be of the same substance.