Since it’s invention in 1902 by Willis Carrier. Air Conditioning has revolutionized living in areas that were previous uninhabitable due to heat. Air conditioning manufacturing companies have been perfecting their units over the years, and the technology is compounding into better performing more efficient units. Many people know that air conditioners cool the air in your home or business, but many don’t know how it is done. In this article I will explain how air conditioners work to help further your knowledge on the subject.
First thing you will need to know about air conditioning systems is that they remove heat from inside to outside. So any heat from inside the home or business will be transferred to the outdoors through a refrigeration medium. There are many different kinds of refrigerants. A refrigerant is classified by having properties that the temperature of the substance correlates with the pressure of the substance. There is a long list of refrigerants that are out on the market, but now the most common refrigerant for home or business units is R-410A. It is the industry standard. R-22 was phased out several years ago due to environmental concerns. R-410A runs at higher pressures than R-22. Most people notice that newer AC units are larger than AC units of the past. More surface area across the coils will allow more heat transfer. Thus being a more efficient unit.
There are various types of air conditioning units that are used in homes and businesses. The most common units used in single story homes and businesses are package units. These are the units that contain both sets of coils and all components of the air conditioner inside one unit. Most newer homes have split systems. These are the systems with an outside unit and an inside unit. The outdoor unit is called the condenser unit, and the indoor unit is called the air handler. Air conditioning units have a variety of heating options. I will go over heating options in another article.
Compressors are the starting points of the refrigeration cycle. It is one of the two points in the refrigeration system that separates the low and high pressures. Compressors will take low pressure low temperature refrigerant vapor, and compress it into a high pressure high temperature vapor. It is important to note that this is vapor and not liquid. Compressors are used move gases. The high pressure high temperature gas leaving the compressor will travel through the outdoor condenser coils. Heat will transfer out from the refrigerant through the condenser coil fins. It will cause the refrigerant to condense into a low pressure warm temperature liquid. After leaving the condenser coil the line is called the liquid line. This is the point that there is usually a filter drier in the system. Some filter driers only allow liquid to travel one way and other filter driers allow liquid to travel bidirectionally. These are installed on heat pump type units.
Low pressure warm temperature liquid refrigerant will then pass through the metering device. This will cause the refrigerant to become cold immediately due to the properties of refrigerants. The older type of metering devices are usually fixed orifices or capillary tubes. For the last 20 years most metering devices are now TXV’s or Thermal Expansion Valves. These metering devices have a modulating orifice that changes the flow of refrigerant in accordance with the amount of superheat in the end of the evaporator coil outlet line. When the cold low pressure low temperature refrigerant passes through evaporator coil. It will gain heat from the air inside the home or business that is transferred through the evaporator coil fins. The refrigerant will then become a vapor again. The amount of vapor at the end of the evaporator coil will continue to gain heat past the point of becoming a vapor. The amount of heat gained past the point of the pressure temperature of the refrigerant is known as Super Heat. The Vapor at the outlet line of the evaporator coil will then travel to the suction side of the compressor. Starting the process over again.
Refrigeration should never leave the system unless there is a leak in the system somewhere. The most common location for the a leak is in the schrader valves where the refrigeration is entered into the system. These valves have a rubber seal that is worn by the corrosive properties is the compressor oil over time.
Thermostats are the separate controlling units that are located in a central point in your home. They are usually located near the return duct of the air conditioner. There are a variety of thermostats available for your needs. Non-Programmable thermostats will not change settings unless manually changed. Programmable thermostats can be set to change temperature set points at various days and times. Smart thermostats are the new type of thermostats that work with the WiFi in your home. They allow you to control the set points and control your AC unit through your smart phone.
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