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How do commercial HVAC systems cool large buildings?


Commercial HVAC systems are complex and require the ability to cool large buildings.  This is especially important throughout the hotter part of the year. Keep the following information in mind, so you know more about how these systems function.


Commercial HVAC System Features


There are several different types of systems for commercial applications. These systems operate at a much larger capacity than a residential air conditioner. They have different components and features that allow them to cool large spaces. Knowing what these are can help you understand how your system works and what might go wrong with it.


Commercial Package Air Conditioning


This type of unit generally does a single space, sometimes multiple units on one space. The system operates much like a residential system with a few kickers. These systems are designed to pass air from an area and mix it with a percentage of fresh outside air. It will then pass that air over a copper and aluminum coil. This coil then absorbs the heat and the moisture from the air, creating cold, fresh air before it is reintroduced to the space.


Features used in this type of system:


  • Air-cooled condenser (Needs to be kept clean and clear. Rinse regularly.)

  • Sealed refrigeration systemIndoor coil or evaporator coil (Filtration is an absolute must.)

  • Electric motors to move outside and inside air across the coils (This allows the process to work.)

  • Manual outside air dampers or fixed percentage dampers

  • Economizer outside air dampers (These adjust based on demand and temperature.)

Commercial HVAC Chilled Water Systems


This type of system is used in large industrial complexes, office buildings, and apartments. The system uses refrigeration tubing inside a chiller barrel to subcool water. It then uses pumps to circulate this water throughout the building. Next, it connects to individual water coil air handlers. This is where the magic happens. Using a coil similar to the one used in air conditioning, water passes through the coil as air passes over the coil. The chilled water absorbs the heat and humidity from the air creating cold air. These systems are very efficient in large complexes.


Features used in this type of system:


  • The cooling tower operates like a condenser using water and air

  • Chiller to super cool the water

  • Mixing valves to control the type of flow

  • Temperature controlled shut off valves to move the cold water where it is needed the most

  • Evaporator coils to pass the air across for the cooling process (Filtration is a must.)

  • Water treatment equipment to control scale build up

Commercial Water Source Heat Pumps


This is the third type of commercial cooling system that marries the two previous versions together sharing both systems’ technology. The system puts an actual mini package unit in your space for cooling. Then it uses a central cooling tower to cool water to 80 degrees.

Next, it pumps that water to each unit’s condenser. Finally, it uses the water instead of air to pass the hot refrigerant through to more efficiently convert refrigerant for the cooling process. These units are extremely efficient because the condenser temperature is constant.

This is unlike the two previous systems whose condensers operate more or less efficient based on the outside air temperature.


Features used:


  • Air-cooled condenser (Needs to be kept clean and clear. Rinse regularly.)

  • Sealed refrigeration systemIndoor coil or evaporator coil (Filtration is an absolute must.)

  • Electric motors to move outside air and inside air across the coils for the process to work

  • The cooling tower operates like a condenser using water and air

  • Temperature controlled shut off valves to move the cold water where it is needed the most

  • Water treatment equipment to control scale build up

Cooling Process for Commercial HVAC Systems


The systems use the following steps for cooling commercial buildings:


  • The HVAC system’s compressor raises the temperature and pressure in the refrigerant.

  • A condenser takes heated air from outdoors and sends it over the refrigerant, which causes it to liquefy.

  • The refrigerant becomes cooler as the pressure inside it decreases.

  • An evaporator in the HVAC system sends heat to the refrigerant, which causes the liquid to change