How Your Air Conditioner Works

 

Air conditioning is the conditioning of air within a defined space, usually a residence or a place of business. Conditioning usually involves heating or cooling, humidifying or dehumidifying, and filtering or cleaning air. If you have a central air conditioner, your system cools and dehumidifies the defined space. Heating is accomplished by an add-on to the system (such as an electric heat strip) or by a seperate unit, such as a furnace.
 

 

 

 

How Your Air Conditioner Cools the Air

 

Central air conditioners are split systems: an outdoor unit (the condensing unit) and an indoor unit (air handler). The function of an air conditioner is to transport heat from one station to another. The vehicle your system uses to carry the heat is called a refrigerant, commonly referred to as Freon.

 

The compressor in your outdoor unit canges the refrigerant (or "Freon") into a high temperature, high pressure gas. As that gas flows through the outdoor coil, it loses heat and condenses into a high temperature, high pressure liquid. This liquid refrigerant travels through copper tubing into the evaporator coil. There the refrigerant expands. Its sudden expansion turns the refrigerant into a low temperature, low pressure gas. This gas then absorbs heat from the air circulating in the duct work. The cooled air is then distributed back through your house or place of business. Meanwhile, the heat absorbed by the refrigerant is carried back outside through copper tubing and released into the outside air.
 

Dirty coils and improper refrigerant levels can cause your system to cool less efficiently than it should. An inefficient system means higher energy bills. It also forces your compressor to work harder than is necessary and can actually shorten the life span of your unit. An annual air conditioning inspection by a licensed technician includes an inspection of the coils and the checking of your refrigerant charge, to insure that your system is running efficiently.
 

 

 

 

How Your Air Conditioner Dehumidifies the Air

 

As the warm air circulating through your ducts passes over the evaporator coil, it is quickly cooled and can no longer hold as much moisture as it did at a higher temperature. The excess moisture condenses on the outside of the coils and is carried away through a drain. The process is similar to what happens when moisture condenses on the outside of a glass of ice water on a hot, humid day.

 

Occassionally, the drain lines may become clogged and your system will not drain properly. This can result in a drain pan overflow, leading to water leaks in your ceiling or walls. An annual air conditioning inspection by a licensed technician includes an inspection of your draining system. During the inspection, the technician will treat your draining system with an algaecide to retard the growth of algae, which can clog your system.
 

 

 

 

The Importance of a Matched System

 

Your cooling system consists of an outdoor unit (the condensing unit) and an indoor unit (air handler). These two components are designed to work together as a coordinated team to provide top performance, maximum efficiency, and comfort. Whenever you install a new outdoor unit, you should install a new, equally efficient "matched" indoor unit at the same time. While replacing the outdoor unit only may initially offer you the lowest price, it may prove more expensive over time. When your air conditioning components don't match, your system may still work, but it won't perform at the promised energy efficiency. In fact, your system could be up to 15% less efficient than stated. You may be sacrificing comfort, as well, as a mismatched system may have difficulty keeping up on the hottest days. Finally, if your cooling system's components aren't matched, it could create undue stress on your cooling system, resulting in unnecessary, premature failure.

 

 

 

 

Heat Pumps

 

A heat pump cools your home or place of building by extracting heat from indoor air and forcing (pumping) the heat outdoors. For diagrams and a more detailed description on how heat pumps work, visit our Heat Pumps web page.

 

If your home or business uses a heat pump, make sure that your heating and air conditioning technician is certified to work on heat pumps before he services your unit. Heat pumps operate on different principals than traditional furnaces and air conditioners and so are engineered differently. Not all state licensed heating and air conditioning technicians are qualified to service heat pumps. To receive heat pump certification, a technician must receive formal training in heat pump design and repair and must pass a test administered by the Refrigeration Service Engineers Society (RSES). ACU Air has been heat pump certified by the RSES.
 

 

 

The Importance of an Annual Cooling Inspection

 

Would you drive a car year after year without ever changing the oil or taking it to a mechanic for a tune-up? Probably not. Like your car, your cooling and heating systems must be maintained in order to run efficiently and dependably. An annual cooling check-up allows a technician to identify minor problems before they become major ones.

 

ACU Airperforms annual cooling system inspections on both residential and commercial structures. Click here for details on what our cooling inspection covers.
 

 

 

 

Glossary

 

 

Air Handler
 

Also known as the "indoor unit", the air handler is the evaporator section of your air conditioning system. It circulates and delivers the cooled air. The indoor unit contains the evaporator coil, an indoor fan motor and, sometimes, a heat strip (for supplemental heating).
 

 

 

Automatic Setback Thermostat
 

An automatic setback thermostat or programmable thermostat allows you to store six or more separate temperature settings for different times of the day. You can set the thermostat with a daily or weekly program. And you can override the settings at any time without affecting the daily or weekly program.
 

 

 

BTU
 

BTU stands for British Thermal Unit: the amount of heat required to raise the temperature of one poud of water one degree fahrenheit.
 

 

 

Compressor
 

The compressor is the "engine" which drives the condensing unit. The condensing unit serves as a pump which compresses the gas in the high pressure (condensing) side of the cooling cycle and causes the refrigerant (Freon) to circulate.
 

 

 

Condensing Unit
 

Also known as the "outdoor unit", the condensing unit pumps vaporized refrigerant from the air handler (indoor unit), compresses it, liquefies it, and returns it. It contains the compressor coil, an outdoor fan motor, refrigerant control valves, and other necessary controls.
 

 

 

Evaporator
 

Found inside the air handler (indoor unit), the evaporator is where refrigerant vaporizes and absorbs heat.
 

 

 

Refrigerant
 

Refrigerant is a substance which absorbs heat by changing states (evaporating) from liquid to gas. It releases heat by changing states (condensing) from gas back to liquid. Most people refer to the refrigerant used in cooling systems (R-22) as Freon. But this is actually DuPont's brand name for R-22. The scientific name for R-22 (or Freon) is halogenated chloroflourocarbon (CFC). Because of its destructive effect on the ozone, the use of R-22 is strictly regualted by the Environmental Protection Agency (EPA). To legally buy and use Freon, an air conditioning technician must own a recovery unit and must be certified EPA certified. Unfortunately, many EPA certified technicians do not always use their recovery units when releasing Freon from a unit. Removing Freon without a recovery unit destroys ozone and is a violation of federal law. You should check carefully with any technician you use about how he handles the refrigerants in your system, since misuse can result in costly fines. ACU Air has an EPA universal certificate and consistantly follow all EPA guidelines for the removal and recycling of refrigerant.
 

 

 

SEER
 

Seasonal Energy Efficiency Ratio is the efficiency rating for air conditioning units. The higher the SEER rating, the better the energy efficiency. SEER is the ratio of the amount of BTU's used for cooling in normal annual use to the total amount of electrial power (measured in watts) over the same period. (Annual Cooling in BTU's/Total Watt Hours = SEER).
 

 

 

Split System
 

A split air conditioning system allows the air handler to be installed in a different location from the condenser. While split systems generally cost more to install than package units, they can save you money in the long run because they are more energy efficient. Another advantage is the reduction of condenser noise. Split systems are also often used where there is a space problem. Ask your ACU Air technician if a split system is right for you.
 

 

 

Thermostat
 

A temperature-sensitive switch that controls your heating and cooling systems. When the indoor temperature drops below or rises above the selected temperature setting, the switch moves to the "on" position, and your heater or air conditioner runs to warm or cool.
 

 

 

Zoning Systems
 

A zoning system allows the home or business owner to control the environment in an individualized and energy efficient way. The residence or place of business can be divided into 2 or more zones. Through the use of fully modulating dampers, the system can selectively cool or heat certain portions of the building at given periods of the day. With some systems, indoor humidity can likewise be displayed and controlled. A popular alternative to zoning is having two or more units in a larger building. Each unit controls the temperature and humidity in a given portion of the building. Consult with an air conditioning design contractor, such as ACU Air, to determine which of these systems would best meet your needs.

 

 

 

 

Related Links

 

How Do Central Air Conditioners Work?
Consumer Energy Information
Air Conditioning: What Makes Air Conditioning Work?

 

 

 

 

 

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