How Commercial HVAC Systems Work

*This post is part of a much larger pillar blog: The Ultimate Commercial HVAC Guide

Introduction

Commercial HVAC systems are the backbone of comfort in large buildings, ensuring that indoor environments remain pleasant and healthy regardless of the external weather conditions.

Understanding how these systems operate is crucial for building managers, engineers, and anyone responsible for maintaining commercial properties.

This article delves into the intricate workings of commercial HVAC systems, focusing on their heating and cooling processes, air circulation, filtration, and other essential functions.

We hope you enjoy!

Commercial HVAC Systems Overview

Before we explain how commercial HVAC systems function, we’re going to set the foundation for what exactly a commercial HVAC system is.

Commercial HVAC systems (Heating, Ventilation, and Air Conditioning) are designed to regulate the temperature, humidity, and air quality in large spaces such as office buildings, hospitals, shopping malls, and industrial facilities.

Unlike residential systems, commercial HVAC units are often more complex, larger in scale, and capable of handling the needs of vast spaces.

Often, commercial HVAC systems are handled by an experienced mechanical systems company, and not a typical tech.

These systems are also handled by an intricate controls system that is integrated into your building, like this one we did for a previous client of ours.

 

 

Now that we’ve covered the basics, the first function of a commercial HVAC system we’ll be looking at is the heating process.

The Heating Process

The heating component of commercial HVAC systems is essential for maintaining comfortable indoor temperatures during colder months.

There are several methods used to generate heat in these systems including (but not limited to):

• Furnaces: Many commercial buildings use gas or oil-fired furnaces. These units burn fuel to produce heat, which is then distributed throughout the building via ductwork.
• Heat Pumps: Heat pumps are versatile components that can provide both heating and cooling. During the heating process, they extract warmth from the outside air (or ground, in the case of geothermal systems) and transfer it indoors.
• Boilers: Some commercial buildings, especially older ones, rely on boilers that heat water or generate steam. The hot water or steam is circulated through radiators or underfloor heating systems to warm the space.

 

Whether your system uses one, or all of these methods to generate heat, you’ll be sure to stay comfortable during the colder season!

Up next, the cooling process!

The Cooling Process

Cooling in commercial HVAC systems is achieved primarily through refrigeration, which involves the transfer of heat from the inside of a building to the outside.

This is done through:

• Air Conditioners: Central air conditioning units use a refrigerant to absorb heat from indoor air. The refrigerant is then compressed and circulated to an outdoor unit, where the heat is released. The cooled refrigerant returns indoors to repeat the process.
• Chillers: Larger commercial buildings often use chillers. These machines remove heat from a liquid (usually water) that is circulated through a network of pipes. The chilled water absorbs heat from the building’s air via air handlers and fan coils, effectively lowering the indoor temperature.
• Heat Pumps: It may come as a surprise, but heat pumps also help with cooling needs! In cooling mode, they operate similarly to air conditioners, extracting heat from the indoor environment and releasing it outside.

 

Now, aside from the basic blocking and tackling that is heating and cooling, there are a few other key functions found in your commercial HVAC system that are worth talking about.

Air Circulation and Ventilation

Proper air circulation is critical in commercial HVAC systems to ensure that conditioned air reaches every part of the building. It also plays a key role in maintaining indoor air quality (IAQ):

• Ductwork: Air ducts are the channels through which heated or cooled air is distributed throughout the building. In large commercial setups, extensive ductwork systems are designed to efficiently move air between the HVAC unit and the various spaces it serves.
• Air Handlers: Air handling units (AHUs) are responsible for moving air through the ductwork. They contain fans that push the air and may also include components for heating, cooling, and humidifying or dehumidifying the air.
• Ventilation: Ventilation is the process of exchanging indoor air with fresh outdoor air. Commercial HVAC systems often incorporate mechanical ventilation to improve air quality by diluting and removing contaminants, odors, and excess moisture.

 

With air circulation and ventilation happening constantly in your system, what’s making sure the air you and your team are breathing is safe?

Enter, filtration! This is something we have a lot of experience with, being a cleanroom and dry room construction company.

Filtration and Air Quality Management

Maintaining high indoor air quality is a crucial aspect of commercial HVAC systems, especially in environments like hospitals, schools, and industrial facilities where cleanrooms are required.

Here’s some of the ways you can achieve a high level of air quality in your facility:

• Air Filters: Air filters trap dust, pollen, and other airborne particles, preventing them from circulating through the HVAC system and into occupied spaces. High-efficiency filters, such as HEPA and ULPA filters, can capture even smaller particles, including some bacteria and viruses.
• Air Purifiers: Some commercial HVAC systems are equipped with air purifiers that use ultraviolet (UV) light, ionization, or other technologies to neutralize or remove pollutants, including harmful microorganisms.
• Humidity Control: Proper humidity levels are essential for comfort and health. Commercial HVAC systems often include humidifiers and dehumidifiers to maintain optimal humidity, which can prevent the growth of mold and bacteria and improve occupant comfort.

 

So, we’ve now officially covered the four most common and important commercial HVAC systems. However, any mechanical systems team worth their salt will tell you that there are a myriad of smaller (yet just as important) processes that take place constantly. Let’s take a look at some of those.

Additional HVAC Processes

Like we mentioned, beyond heating, cooling, and air circulation, commercial HVAC systems may (but don’t have to) incorporate several other processes to enhance performance and efficiency such as:

• Energy Recovery Ventilators (ERVs): ERVs capture energy from the exhaust air and use it to pre-condition incoming fresh air, which can reduce the heating and cooling load on the system.
• Zoning: Zoning allows different areas of a building to be controlled independently. This is achieved by dividing the HVAC system into zones, each with its own thermostat, enabling more precise control of temperatures across the building.
• Building Automation Systems (BAS): Many commercial buildings utilize BAS to monitor and control HVAC operations. These systems can optimize performance, reduce energy consumption, and provide real-time data on system health and efficiency. These are the control systems we discussed in an earlier paragraph.

 

With all of these excellent commercial HVAC systems in mind, as always, it’s important to take care of your investment, and have the proper preventative maintenance done to ensure everything continues to run as expected.

Maintenance and Efficiency

Regular maintenance is vital for the efficient operation of commercial HVAC systems. This includes routine inspections, cleaning of filters and coils, checking refrigerant levels, and ensuring that all components are functioning correctly. 

Preventive maintenance not only extends the lifespan of the system but also helps in identifying potential issues before they escalate into costly repairs.

If you don’t have an in-house team to take care of this maintenance, make sure to contract a mechanical systems team that really knows what they’re doing.

Efficiency is another key consideration. Commercial HVAC systems are significant energy consumers, so optimizing their operation can lead to substantial cost savings. 

Energy-efficient equipment, proper insulation, and smart thermostats are just a few of the ways to improve the efficiency of these systems.

Make sure to check out these articles we’ve written on energy efficiency.

Conclusion

Commercial HVAC systems are complex yet essential components of modern buildings, ensuring comfort and air quality for occupants. 

By understanding how these systems work—from heating and cooling to air circulation and filtration—building managers can better maintain and optimize their HVAC systems for peak performance.

If you’re interested in learning more about how we can help with your mechanical systems needs, contact us!