What is an HVAC Compressor? The Ultimate Guide to HVAC Compressors

HVAC compressors are crucial components of any heating, ventilation, and air conditioning system. They don’t just play a critical role in ensuring systems can work (by compressing refrigerant), they can also improve the overall efficiency and performance of your climate control system. 

What many commercial building owners don’t realize, when they’re investing in a new HVAC system, is that there are various types of air conditioning compressors to choose from. Each option has its own distinct pros and cons, and choosing the right system is crucial to getting the best return on your investment, reducing your carbon footprint, and keeping costs low. 

As experts in delivering innovative HVAC solutions to commercial buildings, DB Sales can help you identify the compressor that will help you reduce energy consumption, and maintain the ideal atmosphere in your facility. Here, we’ll introduce everything you need to know about the common types of HVAC compressor, so you can make the right choice.

Understanding HVAC Compressors

A HVAC compressor, or air conditioning compressor is potentially the most vital part of your system, because it’s the solution that facilitates the entire cooling and heating cycle, circulating refrigerant to all other parts of the system. 

In an air conditioning system, the compressor helps to transfer heat out of a building during the cooling process, and directs heat into the building during the heating process. By compressing the refrigerant gas, the compressor raises its temperature and pressure, allowing it to release or absorb heat effectively. More than just ensuring your HVAC system can operate correctly, an air conditioning compressor contributes to:

For commercial buildings, choosing an energy-efficient air conditioning compressor, aligned to the specific needs of your facility is essential. The right choice is how you ensure you can reduce operational costs, comply with energy regulations, and improve building comfort. 

How Do HVAC Compressors Work?

AC compressors are the hearts of HVAC systems. They work in tandem with other HVAC components, such as expansion valves, condensers, and evaporators, to enable efficient temperature control. In a HVAC system, the process of cooling begins in the “evaporator”, where low-pressure refrigerant absorbs heat from the indoor air, transforming it into a gas. 

This gas then flows into the compressor, where it’s compressed to increase the pressure and temperature of the refrigerant. As the pressure and temperature of the refrigerant increases, it’s driven towards the condenser. The condenser then uses the high-pressure gas to release heat into the outdoor environment, and the refrigerant condenses back into a liquid state. 

The liquid refrigerant then moves through an expansion valve, reducing in pressure before it returns back to the evaporator, and the cycle begins again. 

When you’re using a heat pump or HVAC system to “heat” a building, the process is similar, but air is drawn in from outside of a building, and pressure is added to the refrigerant to increase the temperature so that heat can be distributed indoors. 

Notably, while air conditioning compressors and refrigeration compressors serve similar purposes, there are some differences between them. For instance, air conditioning compressors operate using refrigerants like R-410A and work under moderate pressure to moderate the temperature of indoor spaces like rooms. Refrigeration compressors use refrigerants like R-134A and function at lower temperatures and pressures. They’re usually designed specifically for cold storage and food preservation applications. 

The Common Types of Air Conditioning Compressors

While compressors are a standard component of any HVAC system, there are different types of AC compressors to choose from, each with their own specific use cases, benefits, and potential challenges to consider. Here’s a quick insight into the most common types of compressors:

Reciprocating HVAC Compressors

A reciprocating compressor is among the most “traditional” types of compressor. They’re suitable for use in appliances, residential and commercial AC, refrigeration, and industrial applications. Reciprocating compressors use a piston moving within a cylinder to compress refrigerant. As the piston moves down, it creates a vacuum that draws in low-pressure refrigerant. The piston then moves up, compressing the refrigerant to a high pressure before it is discharged.

These compressors offer exceptional efficiency for various use cases, and are extremely versatile – they can even be used with different types of refrigerant. However they’re typically best for low to moderate applications, and can struggle with high-demand situations. Many reciprocating compressors may also be noisy, and require more maintenance than alternative solutions. 

Rotary Compressors

Rotary compressors are another extremely common option in most heat pumps and air conditioning systems. They’re portable, quiet, and convenient for companies that want to avoid noise pollution (such as those in the hospitality and healthcare industries). 

A rotary compressor uses a rotating mechanism, such as a cylinder or blade to compress refrigerant. As the rotor turns, it builds a vacuum to draw in refrigerant, which can then be compressed and expelled. These compact compressors are easy to install, and deliver continuous airflow operation with minimal noise. However, they can be expensive compared to reciprocating compressors, and sometimes require more frequent maintenance due to their moving parts. 

Screw AC Compressors

Screw compressors rely on two intermeshing helical rotors to compress refrigerant. As the rotors turn, they trap refrigerant in pockets and consistently compress it. This design allows for continuous operation and a steady flow of refrigerant. Screw compressors are extremely reliable and efficient. They can deliver excellent energy efficiency, and are perfect for various applications, including industrial and commercial purposes. 

However, these compressors can be more expensive to purchase initially than other types of compressors, and they’re often quite large, which means you need more space for an installation. Plus, the use of various intricate parts in these systems could lead to higher maintenance costs.

Centrifugal Compressors

Often recommended for extra-large HVAC systems and industrial applications, centrifugal compressors are designed to function effectively at high speed. These HVAC compressors have fewer moving parts than some alternatives – there are no valves or pistons. Instead of using those components, centrifugal compressors rely on a rotating impeller to increase refrigerant velocity.

As refrigerant passes through an impeller, it it’s charged with kinetic energy, which is converted into pressure energy within a diffuser. Centrifugal compressors offer excellent efficiency at large flow rates, and benefit from relatively low levels of vibration and noise. However, they’re larger, more expensive, and more complex to maintain than some alternatives.

Scroll Air Conditioning Compressors

Sometimes referred to as “scroll vacuum pumps”, scroll AC compressors are a slightly newer innovation in the HVAC space. They use two spiral-shaped scrolls, one that’s fixed, and another that’s orbiting, to compress refrigerant in a system. As the orbiting scroll moves, it traps refrigerant in pockets to compress it towards the center, where it can be discharged. 

Scroll compressors can be an attractive option for a few reasons. They have a simple design that helps to reduce energy consumption and improve efficiency. Plus, they require very little maintenance. However, they can be quite expensive, and they’re rarely suitable for larger systems or intense operating conditions. 

How to Choose the Right Air Conditioning Compressor 

There’s no one-size-fits-all AC compressor that’s ideal for every application. The right solution for you will depend on numerous factors, including your budget, your system requirements, the size of your building, and your priorities surrounding sustainability, energy efficiency, and noise levels. 

The key things you’ll need to consider include:

• Your system requirements: Carefully evaluate the specific requirements of your HVAC system to define the type of compressor you’ll need. Consider your cooling requirements, common load variations, operating conditions, and the size of your building. 
• The ideal size: Choosing the right size for your compressor is crucial. An oversized compressor leads to increased costs, and short cycling, while an undersized solution will struggle to meet with your building’s demands. 
• Applications: Different applications necessitate specific compressor types. For instance, a commercial kitchen may require a refrigeration compressor, while an office building may benefit from a scroll compressor.
• Maintenance needs: Each type of compressor has different initial costs and maintenance requirements to consider. Larger, more advanced systems may be more initially expensive, and have more maintenance costs, but may save you money by improving energy efficiency and the performance of your HVAC system int  he long-term. 
• Energy efficiency: In regions with strict environmental regulations, prioritizing energy-efficient compressors can significantly reduce energy costs and comply with standards. Look for models with high SEER (Seasonal Energy Efficiency Ratio) ratings.
• Noise levels and vibrations: Consider the noise level and vibration produced by the compressor, especially in noise-sensitive environments such as hospitals or schools. Options like rotary compressors may be a good choice when noise is a concern. 

Choosing the Ideal HVAC Compressor for Your Needs

Choosing the right HVAC compressor for your needs is crucial to ensuring your system functions efficiently, and effectively. With the right choice, you’ll not only improve your climate control process, but reduce energy costs, and improve system longevity. 

If you’re unsure which HVAC compressor is going to be the right choice for your commercial building, reach out to DB Sales. Our experts can help you identify the best air conditioning compressor for your use case, and install the perfect solution for your building.

Contact us today for more information, or to get a customized quote.