As 2020 comes to an end, experts predict that a warming climate and global pandemic will lead to doubling demand in energy usage for air conditioning and ventilation in the year to come. Peak electricity usage across commercial and large residential complexes comes primarily from the air handling unit, where fans can consume up to 80% of a building's total energy.
Air handling units are responsible for heating, ventilation, and air conditioning in every building, which are critical not only for occupant comfort, but also for healthy indoor air quality and the reduction of airborne diseases.
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• Indoor Air Quality
• Energy Efficiency
• Electric Motors
To solve the dual challenges of sustainability and healthier indoor air, today’s HVAC specialists rely on Fan Array technologies. A Fan Array is an air handling unit composed of multiple small, lightweight, affordable, and extremely energy-efficient fans. Older air handling units are typically large, belt-driven blowers that are heavy, costly to maintain, noisy, and inefficient.
Fan Arrays are the latest in green technologies by the HVAC industry and data centers for server cooling. Energy-intensive operations that need continuous airflow prefer Fan Array setups because they consume much less electricity, run quietly, and can adjust speeds depending on environmental conditions.
In the last decade, Fan Arrays have become the most popular choice for a building’s sustainability profile, able to offer energy efficiency levels up to a whopping 94%.
Here are the top 5 advancements in Fan Array technologies in 2020 that contractors, HVAC manufacturers, and building owners can expect to come across in their AHU retrofit projects.
#1 Over 90% EC Motor Efficiency
Electronically commutated motors, also known as ECMs, have been around for a few decades. If you’ve ever seen the fan inside a laptop or personal computer, you’ve seen a miniature version of an EC motor in action. These motors generate energy savings up to several tens of thousands of euros over their lifetime, according to the European Commission, which recommends using ECMs in HVAC applications to meet future green sustainability goals.
It’s only recently, however, that the HVAC industry has been able to leverage these motors, rated for over 90% efficiency in large-scale commercial projects. Advancements in the motors’ construction and efficiency profile and cheaper manufacturing costs have lowered barriers to entry so that anyone can access these fan technologies affordably.
EC Motors can’t get very big, or they lose efficiency, which is why multiple smaller fans are placed together, forming an array. Together, they move the same volume of air as a large single-blower unit, but offer greater reliability and control—in the event one fan fails, other fans can compensate by speeding up without any interruption in service.
An ECM is a digitally-powered fan. This means it has an extended lifetime over belt-driven fans, due to low operating temperatures and no mechanical parts that create debris or wear-and-tear. With fewer parts and the lack of oil or grease, ECMs are less of a headache to maintain over their lifetime.
Combining electronic controls with brushless, magnetic motors, ECMs can maintain peak efficiency across a wide range of variable speeds. These controls are now so precise that fans can be turned down to fractions of their maximum speed while still maintaining around 90% energy efficiency.
#2 Improved Fan Array Configurations
Fan Arrays, also referred to as fan walls, have seen rapid improvements in design configuration. While the EC motors themselves in each fan are efficient, the array of all fans working in unison can have a significant impact on energy efficiency and spatial footprint.
A good HVAC Fan Array provider will be able to offer builds that consist of 4, 6, 8, or 12 or even dozens of fans. In modern Fan Arrays, each unit can be stacked vertically or horizontally like Lego blocks, making it easy for a single technician to hand-carry units and set them in place. Instead of supplying each fan with its own power, each unit is fully integrated, using a single connection to a power source.
Since these fans can be stacked vertically, a Fan Array also typically has a much smaller footprint than older, belt-driven blowers. Legacy air handlers often require heavy machinery to lift during maintenance procedures, increasing downtime and driving up maintenance costs.
With a slim profile, Fan Arrays offer much easier accessibility for technicians to clean, maintain, and repair units — even within the smallest of size constraints. A fan array configuration should be customized to the space and use cases that it is best suited for. This configuration can be shown during the planning stage with digital mapping software, showing the client their optimal setup before any order is made.
#3 Advanced Engineering in Impeller Designs
Modern Fan Arrays use fan types made of high-performance composite materials and aerodynamic shapes to achieve their efficiency ratings. Backward-curved blades, or a centrifugal fan, are named so because of how air flows and exits the fan radially, equally from the outer circumference of the fan. The entire rotor and fan system is known as an impeller.
The impeller usually consists of 7 backwards curved blades in a rotor frame, which can come anywhere between 7.5 to 12 inches, depending on the application.
Unlike other fan types, a backward curved centrifugal fan does not have a point at which operation stalls—it can be slowed down while still moving air at a large range of speeds. They also yield the highest static efficiency compared to different types of fans, meaning they can be placed in formations and enclosures to direct airflow that other fan types cannot accommodate. For example, axial, diagonal, and forward-curved centrifugal fans have strict operating ranges that are advised. Otherwise, they can create turbulence at higher speeds, or cease operation altogether at lower speeds.
Fan Array Technology.
The materials used on fans also matter. High-performance polymers, stainless steel, and specialized coatings can dampen sounds from the impeller and motor. This means ancillary components to dampen sound (like noise-proofing material) are unneeded, since the fans themselves provide this feature.
#4 Enhanced Fan Array Manufacturing Processes
New manufacturing processes involved with Fan Arrays have been a key driver in their adoption among HVAC specialists in 2020. Robotic manufacturing processes can reduce lead times to mere weeks instead of the months required to build and ship large belt-driven air handlers.
Key Fan Array manufacturers use Artificial Intelligence, automation, and robotics to ensure repeatability and quality precision in key parts. Production mistakes and human errors can be significantly reduced or even eliminated.
Fan Array configurations also offer pre-installed and wiring and control components by the manufacturer, saving time, labor, and headache when retrofitting units on-site.
#5 Smart HVAC and Air Handling Software
Internal electronics in a Fan Array offers new opportunities for greater control and digital monitoring features. Every part of a Fan Array has sophisticated electronics built-in for communication, allowing automated software to adjust speed, send performance data, or trigger warnings before anything goes wrong. This type of predictive maintenance can save building owners from any outages and ensure continuous smooth operation from the occupants’ perspective.
Automated system optimization can slow down or speed up fan usage as needed in response to changing conditions, power usage, or failure in any part of the array. These can also be manually attuned to meet certain energy-usage thresholds, ensuring peak efficiency during different times of the day, changing seasons, or increased traffic.
Forging a Path Forward in 2021
Cleaner indoor air and energy efficiency will continue to drive global HVAC demand as we move into 2021. The cost-saving features of a Fan Array are led mainly by a confluence of technology breakpoints: more affordable parts, robotized manufacturing, improved material sciences, and digital fan design improvements.
As we look toward sustainable technologies in our living, entertainment, and working spaces, it is often the unseen air handling unit which can create the most change. By replacing old legacy air handlers with Fan Array technologies, building owners can achieve their green goals while also reducing operational overhead costs.