May 17, 2021

Commercial HVAC systems are usually in office spaces, shopping centers, and retail stores. The unit contains various components that work together to ensure optimum performance. If one part has a problem that goes unnoticed, it could affect the entire system, causing it to break down.

The building will then become chilly or sweltering hot, affecting employees’ productivity and customers’ comfort. You, therefore, need to know how different components of the system work to spot mechanical issues early enough before they escalate into major problems. Here are the essential parts that make up a commercial HVAC unit.

1. Thermostat

The thermostat connects to the HVAC system through special wires, and it controls the unit’s functionality. It signals the system to produce cool or hot air based on the set temperature. The thermostat’s temperature sensor indicates whether the heating system or air conditioner should be running or turned off.

If there are thermally controlled zones in a building, they should have their thermostat to maintain the required temperature. It should be located on a prominent and easily accessible wall.

2. Air Conditioner

The air conditioner in a commercial HVAC system is similar to that of a residential unit. Its primary purpose is to draw heat from the indoor air, transfer it into the outdoors, and recirculate cooler air into the house. The air conditioner also dehumidifies the building.

In most cases, the air conditioner is usually a split system where part of the unit is in the building while another section is outside. When the unit draws hot air from the building, a chemical refrigerant absorbs the heat and expels it outside.

However, it’s worth noting that the air conditioner doesn’t cool a building alone. It works along with other parts and subsystems to adequately regulate temperature.

3. Compressor

The compressor is the heart of every HVAC unit, which circulates the refrigerant through closed loops between the evaporator and condenser coils. It’s typically located outside, and its vital role is to change the refrigerant into the needed state. The gaseous refrigerant flows into the compressor under low pressure. Motors in this compartment will squeeze the refrigerant to raise it in temperature and pressure. The hot refrigerant then pushes through into the condenser.

Regular compressor maintenance is crucial for the optimum performance of your air conditioner unit. During tune-ups, the technician will check the unit for any damages or electrical problems that could cause malfunctions. Note that compressor repair is limited, and once it malfunctions, replacement may be your only option. Depending on the severity of the issue and your unit’s age, you might even have to replace the entire HVAC system.

4. Condenser

A condenser is an outdoor unit that acts as the heat exchanger in an air conditioning unit. Mainly it transfers the heat drawn from the building into the outdoors. It contains a series of piping and a fan to draw air across the coils and facilitate heat transfer.

When the high-temperature, high-pressure refrigerant gets into the condenser, cooler outside air blows over the coil, absorbs heat from the refrigerant and pushes it to the outside. The refrigerant then flows through into the thermal expansion valve.

5. Thermal Expansion Valve

This is an essential part of the air conditioning process that lowers pressure from the liquid refrigerant to expand. The refrigerant then changes from a liquid into vapor and flows into the evaporator coils. When the refrigerant gets into the expansion valve, it’s usually hot, but the reduced pressure will allow it to leave at its coldest level. The thermal expansion valve can be inside the air handler or fixed at the front part of the evaporator coils.

6. Air Handler

The air handler contains a blower, the component that moves air throughout the house. It also holds the evaporator coil with the chilled refrigerant from the compressor. The blower draws hot air from the building and passes it over the evaporator coil. From here, the refrigerant absorbs heat from the air, changes back into a gas, and returns to the compressor.

The blower is also responsible for circulating cooled or heated air into the building. The air handler contains other subcomponents like dampers, chambers, racks, sound attenuators, cooling, and heating elements. Of all the different parts in this compartment, the evaporator coil is the one that requires great care and maintenance.

7. Terminal Units

The terminal unit is an air handling device that regulates the volume of conditioned air entering various zones within a building. The unit consists of a filter, coils, and blowers. The filter’s primary purpose is to remove dirt, dust, pollen, and other contaminants from the air. Clogged air filters can reduce airflow, which affects the system’s efficiency. They are usually located somewhere near the return duct, at the ceiling walls, or in the air conditioner.

It’s a good idea that you clean or replace the filters each month to enhance the unit’s efficiency. If you run your system very often or the building is in a very dusty area, the filters may need more frequent attention.

8. Chiller

Large buildings can opt to use chillers as the cooling component of their HVAC unit. Chillers can either be air or water-cooled, and their primary role is to remove heat from the liquid running through pipes in a building. The air-cooled chillers have condenser coils cooled by fan-driven air. The unit is usually located outside.

Water-cooled chillers work well for buildings that require intense cooling for an extended period. They work through continuously recirculated water, which carries heat and delivers cool water from an exterior cooling tower.

9. Furnace

The heating system works as an opposite version of the cooling process. For those HVAC units with a furnace, the heating process begins with the thermostat signaling the furnace. A gas valve opens and ignites the burner to generate heat. It flows through the heat exchanger, which transforms the heat into the air. The internal fan and motor attached to the furnace will then push the heated air into the ductwork. The blower distributes the air throughout various rooms.

10. Duct System

The ductwork delivers cooled or heated air into different rooms in a building and returns unconditioned air into the HVAC system. This part shouldn’t be overlooked since it affects the efficiency of your HVAC unit. Schedule for regular ductwork cleaning with a professional. An expert will also assess the nature of the duct system to determine its compatibility with your HVAC unit.

Bottom Line

Understanding the essential parts of a commercial HVAC system and how they work plays a role in maintaining comfortable temperatures in a building. If something goes wrong, you will let your HVAC company know the exact issue to quickly get your system fixed and back to working conditions. A commercial HVAC system contains complex components, and performing DIY repairs may be a challenge. Whenever you experience an issue with your unit, it’s a good idea that you seek help from an experienced technician.

If you need professional help with your HVAC unit, you can always reach out to Beyer Mechanical. We provide commercial HVAC unit installation, repairs, and maintenance services in San Antonio, TX. We also deal with professional HVAC construction. Call today to book an appointment and enjoy our exceptional services. We look forward to serving all of your home climate comfort needs.

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