In order to make our home and workplace cool, we need an air conditioner. It is a central heating and cooling system capable of providing cool air. By making use of the duct work for the home, the AC draws out the warm air inside and also removes its heat, and finally, replaced by the cooler air. In other words, it can be said that an air conditioner is capable of taking in the heat energy of outside and then transfers it. It has the power to change the humidity, temperature, and general quality of the air.
One interesting thing to be noted that the working of an air conditioner and a refrigerator is almost the same. The only difference is that a small and insulated space is made cool by the refrigerator. Whereas, the home, office, or commercial space is kept cool at a comfortable temperature by an air conditioner.
There is the use of chemicals by the air conditioning unit, which is then converted to liquid from the gaseous state and back again. With the help of these chemicals, the heat from the air inside the property gets transferred into the outside air. In order to make the temperature of the air in your property comfortable, a simple scientific principle is used by the air conditioning unit and the remaining part is achieved by mechanical means.
An AC unit basically has the following parts- evaporator, compressor, condenser, expansion valve, and refrigerant. In the evaporator, the heat inside the room is collected by a refrigerant gas. In this part, heat is absorbed by the liquid refrigerant which then evaporates to become gas. The most common refrigerant gases used are hydrocarbons, hydrofluorocarbons, or hydrochlorofluorocarbons. Next comes the role of the compressor which is located in the outdoor unit. In this part, the gaseous refrigerant is compressed. From the compressor, the vaporized refrigerant passes to the condenser, which is also located in the outside unit of the AC. This gaseous refrigerant is then converted into liquid due to which heat is expelled outside. Evaporator has got chilled coils and the condenser has hot coils. In between these two sets of coils, is the expansion valve or throttling device. Its function is to keep an account of the amount of refrigerant that moves in the evaporator.
What are the Types of AC Units?
Depending on the space, there are six different air conditioners available. These are central AC, ductless, window unit, hybrid, portable and geothermal unit. Selecting a good air conditioner unit entirely depends on your budget, SEER ratings, features, square footage, and warranty. You need to look into all these before opting for a particular unit.
Working of an Air Conditioner
It works on the principle that hot air collected is processed inside the evaporator with the help of a refrigerant and a bunch of coils and cool air is released in the same space.
As soon as an AC is switched on and the desired temperature is set, the thermostat (installed in the unit) gets to know that the temperature set is different from the temperature of the room.
At the base of the indoor unit, lies a grille. Through this grille, warm air is drawn and flows through the evaporator coils containing the refrigerant. The heat is absorbed by the refrigerant due to which it becomes a hot gas. This represents the way of removal of the heat from the air. Along with absorbing the heat, evaporator coils also help to dehumidify the room by removing moisture from the air.
The compressor is on the outside unit, is responsible for carrying the hot refrigerant gas, and compresses it so that it becomes hot. Generally, temperature increases when a gas is compressed.
The condenser is the next component that comes into play. After getting compressed, the high-pressure gas travels to the condenser where the hot gas is condensed and gets converted into a liquid.
In the condenser, the refrigerant is present as a hot gas which soon becomes a cooler liquid because metal fins help in scattering the heat of the hot gas to the surroundings. This indicates that the refrigerant loses its heat as it leaves the condenser and finally becomes a cooler liquid. The expansion valve is a tiny hole in the copper tubing of the system which is responsible for controlling the flow of cool liquid refrigerant into the evaporator. This is the point where the journey of the refrigerant has started and thus, the refrigerant comes back to the starting point.
Till the desired temperature is achieved, the entire process is repeated over and again. While concluding, it can be said that the work of an AC unit is to keep taking in warm air and expelling it back in the room until there is nothing left to cool.
In a window AC, there is a small metal box in which all the components of the air-conditioning process are present and the process of cooling remains the same.
Effects on Health
It is common to suffer from heatstroke, dehydration due to excess sweating, and hyperthermia problems in hot weather. In developed countries, heat waves are often experienced. With the help of an air conditioner, incidences of issues related to heatwaves can be reduced. It helps in providing a clean, hypoallergenic, and safe atmosphere in an enclosed area like a home, office, hospital, etc. It is observed that micro-organisms grow and spread in areas where water cooling towers are not maintained. Thus, it becomes extremely important to clean the cooling towers to reduce and avoid these health hazards.
Selection of Refrigerants
Refrigerant has a significant impact on the environment as well as on the performance of the air conditioner. It should be selected wisely as some common refrigerants lead to global warming. Earlier R-12 was used as a refrigerant but it led to ozone layer depletion due to which harmful UV radiations are able to reach the earth’s surface. Due to its harmful effect, this has been replaced by R-134a refrigerant which is safe for the environment. It does not cause depletion of the ozone layer.