~ Reducing contaminant ingress and extending service life ~
Heating, ventilation, and air conditioning (HVAC) systems aren’t just essential to controlling temperatures and air quality inside buildings — they could contribute towards massive global savings. An ‘Efficient cooling scenario’ proposed by the International Energy Agency (IEA) suggests that doubling the energy efficiency of air conditioning could reduce investment and running costs in these systems by nearly $3 trillion by 2050. Here, Chris Johnson, managing director of bearing specialist SMB Bearings, explains how one way to make HVAC systems more efficient is through the better use of advanced sealed bearings.
HVAC systems operate in harsh environments where dust, moisture and contamination threaten the integrity of components. Those components include bearings, which are essential in the fans, motors and compressors used in commercial air handling units, industrial refrigeration systems and large-scale ventilation systems. These systems are commonly found in factories, hospitals and office buildings.
Take an HVAC system in a large commercial building, for example. If bearings begin to fail then friction increases, which causes components to overheat. Over time, the excessive heat can lead to the misalignment of shafts and fans. As this misalignment worsens, vibrations can increase and place further stress on the system. Eventually, the motor will struggle and consume more energy to maintain its performance.
If left unchecked, the motor can seize entirely, halting airflow and disrupting climate control. These issues not only result in higher energy costs, but can present safety risks as overheating components can lead to fire hazards or breakdowns.
For example, during heatwaves in Ghaziabad, India, extreme temperatures have caused HVAC systems to overheat and ignite, leading to a rise in air conditioner fires. According to The Times of India, many of these fires are due to poor maintenance, overloaded circuits and aging components.
Fortunately, sealed bearings — bearings enclosed with seals or shields to prevent contamination and retain lubrication — can address some of these challenges. They not only enhance the reliability of HVAC systems, but can also reduce the frequency of maintenance interventions. This leads to an overall lower total cost of ownership (TCO).
Optimising bearing procurement using TCO
A common mistake when procuring bearings for HVAC systems is to focus solely on the initial cost. This can be misleading, as bearings with a lower upfront price could result in higher maintenance requirements and replacement costs over time. Instead, buyers should adopt a TCO approach that considers the entire lifecycle costs of the bearing including purchase price, installation, maintenance and potential downtime.
Let’s use the example of gearboxes and geared motors, which are integral to many HVAC systems and provide the necessary torque and speed control for various components. Bearings within these systems ensure smooth operation, reduce frictional losses and increase the HVAC system’s overall efficiency.
Sealed bearings are especially suited to gearboxes, because they prevent the ingress of lubricants and contaminants that would otherwise compromise the gearbox’s performance. By maintaining the integrity of lubricants and protecting internal components, sealed bearings contribute to the longevity and reliability of gearboxes and geared motors, and ultimately improve the performance of the overall system.
Sealed bearings also offer significant cost savings over time. Their ability to resist contamination reduces the need for frequent lubrication and maintenance, thereby extending service life and enhancing system reliability.
Lubrication is critical for sealed bearings in HVAC systems as it minimises friction, dissipates heat and prevents wear. Sealed bearings can come pre-lubricated, in order to require minimal maintenance. However, in demanding environments or high-load applications, periodic relubrication may be necessary to maintain the bearing’s performance and extend its service life.
Ensuring safety and compliance in explosive environments
Certain HVAC applications operate in environments where explosive gases or dust are present. In such settings, it is paramount to ensure that all components meet safety and compliance standards.
Bearings used in these environments must meet stringent standards, like ATEX 2014/34/EU, a European Union regulation for the use of equipment and protective systems in potentially explosive atmospheres (ATEX) where a mixture of air, gases, vapours, mists or dusts can ignite under certain operating conditions. There is also the international IEC System for Certification to Standards Relating to Equipment for Use in Explosive Atmospheres (IECEx).
Choosing the right bearings
Selecting the appropriate bearings for HVAC systems involves considering factors such as load capacity, speed, operating environment and maintenance requirements. Sealed bearings for HVAC systems come in three main types: contact seals, non-contact seals and metal shields.
Contact seals provide superior protection against dust, moisture and contaminants; but they can also increase friction and reduce speed. Non-contact seals offer a balance with good contamination protection and minimal impact on speed, which makes them ideal for high-speed HVAC components.
Meanwhile, metal shields prevent larger particles from entering, and are suitable for applications where speed and temperature resistance are critical. Selecting the appropriate seal type ensures HVAC system efficiency, longevity and reliability.
The IEA’s ‘Efficient cooling scenario’ highlights the need for more efficient air conditioning solutions to prevent excessive electricity demand growth. It projects that doubling the energy efficiency of air conditioning by 2050 would prevent global electricity demand from growing by 1,300 gigawatts and save up to 2.9 trillion USD.
High-performance components, like sealed bearings, already play a vital role in achieving these efficiency gains. By preventing contamination, minimising maintenance and improving reliability, bearings can support the global drive for energy savings.
Visit SMB Bearings’ website for more information on sealed bearings for industrial applications.
