The Anatomy of a Commercial Air Conditioning System 

As the temperatures begin to rise in the spring and peak over the summer months, so do the number of news stories regarding heat stroke (AKA sunstroke and heatstroke), where an individual’s internal temperature can reach 104°F or higher within 15 minutes of exposure or excessive exertion. 

 As a result, a working air conditioner quickly becomes a necessity for most of the country and a legitimate life saver for residents of the ten hottest states. 

Rank  State  Average Temp.  Average Summer Temp 
1  Florida  73.4°  82.6° 
2  Louisiana  68.5°  82.9° 
3  Texas  68.0°  84.8° 
4  Georgia  66.2°  80.2° 
5  Mississippi  66.1°  81.5° 
6  Alabama  65.4°  80.4° 
7  South Carolina  65.4  79.7° 
8  Arizona  62.9°  79.9° 
9  Arkansas  62.8°  80.5° 
10  Oklahoma  62.8°  82.8° 

 While humans have used various crude air conditioning techniques (creating shade, changing location, and manual and mechanical fans) for centuries, you can trace today’s modern air conditioning systems back to 1902. 

Who Invented Air Conditioning? 

Air conditioning has changed people’s work environments and lives over the last 120 years. In fact, without air conditioning, our world would look much different. 

  • The modern high-rise building would not be possible.
  • Today’s supermarkets would look and function much differently.
  • Many of today’s common vaccines and medicines would not exist.
  • Computer servers, laptops, and the internet would still belong in a sci-fi program.
  • Medical treatment, surgery, and recovery would have higher mortality rates.

If the automobile was the most significant technological advance of the 20th century, then air conditioning must be number two on that list. 

Willis Carrier invented the first functioning AC system in 1902 to answer the original question. As the story goes, while waiting on a train platform in Pittsburgh, Willis realized that drying air was possible by moving an air stream through the water to create a fog. From there, he could control the air’s moisture, humidity, and temperature.  

The term “air conditioner” is credited to a mill engineer named Stuart Cramer. Shortly after Carrier introduced his new air-cooling system, Cramer invented a similar cooling device. Still, his machine added moisture to make hot mill work environments more comfortable while increasing productivity. Since Cramer’s version did more than merely cool the air, he settled on the name air conditioner.  

Then, in 1940, Frederick Jones received the first patent for a portable AC unit and launched Thermo King shortly after. Next, Jones installed mobile systems on his delivery trucks to deliver food, blood, and crucial medications to the front lines during WWII. After the war, numerous car, train, and airplane manufacturers discovered and incorporated his portable system. 

Commercial Air Conditioning System Components 

Central air conditioning systems use two primary components: the exterior unit (compressor) and the indoor unit (your furnace). While the furnace keeps you warm all winter, it also plays a crucial role in the cooling process. 

Since the indoor unit does most of the work, let’s look at its components first. 


The thermostat works much like the ignition key for your car. Whether you want to heat or cool, the first step is to select from heat/cool/fan options and set the desired temperature. 

Evaporator Coil 

Here is where your furnace becomes part of the air conditioning system since the evaporator coil resides inside the furnace unit.  

 When you turn on the AC, the system draws interior air into the system and across the evaporator coil, where the refrigerant gets cooled by removing heat and humidity from the flowing air. Then with the help of the blower, the cooled air is sent back into the building. 

Expansion Valve 

This valve controls the amount of refrigerant sent to the evaporator coil. Too much and the refrigerant can settle at the bottom of the refrigerant lines. Too little forces the system to work harder to produce the same amount of cooled air. 

 Blower and Blower Motor 

Designed to create air movement, the blower uses a rotating motor to distribute the cooled air throughout the unit or building. 


No matter the size or composition, air filters perform two distinct functions. 

  1. Filters prevent dirt, dust, and debris from entering the system. Excessive dust accumulations can result in overheating, excessive wear, and a shortened life cycle.
  2.   Filters protect tenants and occupants by blocking allergens, dander, and dust from entering your lungs, which can cause inflammation and discomfort.
  3.  Regular cleaning or replacement can maximize AC performance while lowering energy usage and unexpected system and component repairs. 


The ducting used to move the air can be rigid or flexible in its construction. And you will find the ductwork above the suspended ceiling, in the attic, and even in the basement areas of a suite or building. Supply ducts carry the treated air back into the building or suite, while return ducts bring used air back to the unit to begin the process again. 

Now let’s look at the outdoor air conditioning unit, typically called the condenser. Like the interior unit, the condenser also houses the remaining four commercial air conditioning system components.  

Condenser Coil 

Essentially, the condenser coil works like the evaporative coil, except in reverse. As the refrigerant passes through the condenser coil, it’s heated instead of cooled. Contrary to popular thinking, air conditioning doesn’t cool the air; it removes heat from the airflow via the condenser, where the heat can quickly dissipate into the outside air. 


Fans help keep the condenser from overheating by moving the heated air up, out, and away from the condenser unit. 


The compressor provides three critical functions of the air conditioning process. 

  1. When the hot refrigerant reaches the compressor, it’s heated again to become warmer than the outside air. This higher temperature ensures that the heat will transfer from the refrigerant to the cooler outside air more quickly.
  2.  The refrigerant must have a way to convert from gas to liquid before being pumped back into the evaporative coil.
  3.  And the refrigerant requires a pump for traveling through the lines between the condenser and evaporative coils where the refrigerant becomes so cold it removes the heat from the air moving across the evaporative coil.

 Refrigerant lines 

These lines utilize copper tubing and provide the following functions. 

  •  The suction line carries refrigerant between the evaporator and the compressor.
  • The discharge line connects the compressor to the condenser.
  • The liquid line connects the condenser to the expansion valve or device.

Always use Type L air conditioning and refrigeration (ACR) tubing when replacing refrigerant lines, as it’s manufactured to be cleaned, dehydrated, and capped to avoid contamination during transport, storage, and installation. 

As you can see, the anatomy of any commercial air conditioning system requires many moving parts working in unison to keep your office or building cool and comfortable during the spring and summer seasons. 

 MaintenX can service and install all makes and models of air-conditioning systems, including:

  •  Carrier 
  • Trane 
  • Lennox 
  • York 
  • Daikin 
  • McQuay 

 Should you have any questions regarding your current air conditioning system, the MaintenX HVAC/R Team can provide the answers, installations, equipment maintenance, and emergency repairs for all commercial AC systems. 

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