What is Air Conditioning?

Air conditioning can be referred to as AC, A/C or even aircon and is the process of removing the moisture and heat from within a living or working space to improve the comfort level of those inside that space. In addition to improving the living conditions of humans it can also be used for animals, computer servers or even to store and display items such as works of art. A fan is used to distribute the air once it has been conditioned to improve the air quality. Units can be sized to cool a small room to enormous units that cool an entire building. Cooling is usually completed through refrigeration although other methods can be employed such as evaporation, free cooling, desiccants (chemicals used to remove the moisture from the air) as well as subterranean pipes. A/C generally refers to systems that cool the air through humidification, cleaning, ventilation and air movement. A complete system of heating, ventilation and air conditioning is more commonly known as HVAC.

Cooling Methods through History

Snow and ice have been used since prehistoric times for cooling although harvesting ice during the winter for use during the summer did not become a popular concept until the late 17^th century when mechanical ice making machines were first being developed. In ancient Egypt, Rome and Persia methods were used to cool houses mostly through water cooling the air. In the 2^nd century in China a rotary fan was invented powered by prisoners walking in a wheel. Later versions included fine jets of water used to cool the imperial palace.

Mechanical Cooling Methods

During the 18^th century mechanical methods of cooling were introduced as experiments were conducted using alcohol and ether to freeze objects through evaporation. The first real breakthrough in this field in Australia occurred in 1851 by James Harrison. He then developed a commercial ice making machine that went into production in 1853 using a compressor. Electrical air conditioning units were first developed in 1902 by Willis Carrier in Buffalo, New York.

Modern Air Conditioning Systems

Modern A/C units are not designed to draw air from the outside, they re-circulate the air that has been cooled inside this produces a level of moisture that must be removed from a catch tray at the base of the unit. This is allowed to run off through a drip hole. By running the compressor in the opposite direction the effect can be reversed and the air con unit can then be used as a heater instead of cooling the air. Another method is to have a heat pump fitted during the installation as this is a more efficient method of use.

An Evaporative Cooler

In regions where the climate is very dry evaporative coolers are the most efficient cooling systems during very hot weather. They are also known as swamp coolers or desert coolers. The method these coolers use is to draw air from the outside through a wet pad such as a sponge which has been soaked with water. Evaporative coolers may feel as they are not working when the outside air is of high humidity and there is not much dry air available for the coolers to cool that air to a comfortable setting inside. Evaporative coolers rely on the outside air being directed through cooler pads to cool the air replacing the warmer air inside through an open door or window. These coolers are cheaper to buy and very simple to maintain and install.

Installation Types of A/C:

1. Window unit A/C’s are installed in an open window. The interior air is cooled by a fan blowing it over the evaporator. A second fan blows outside air over the condenser. A house or building may require several units to function efficiently although an advantage is individual rooms can be cooled as and when required.

2. There are several types of split systems where the internal heat exchange unit is located some distance from the external one. They can be used to condition the air of a single room or a few rooms within a building from one external unit. They can be used for both cooling and heating purposes. These types of air conditioning systems are the ones we see mostly installed at the moment, as they are not too intrusive in the interior and they are the most efficient systems available. 3. Central or ducted air conditioners offer multi-zone temperature control and can be used as forced air for heat in the winter or chilled air throughout the building during the hot months of summer. we see these units installed more and more as better systems come into the market.