article The Benefits of Fan Array Over Traditional Air Handling Units_In order to make workers and tenants feel safer about returning indoors, many commercial buildings are revamping their air handling units (AHUs) to handle increased air turnover rates. Powering AHUs accounts for the majority of energy consumed by HVAC systems, so property owners should target energy savings at the AHU level before any other components. New products and installation methods are making it possible for building owners to meet rising standards for better indoor air quality, reduced energy usage and easier maintenance.




These demands will continue to grow by 19% to USD 9.54b by 2024, as indoor environmental health concerns continue to be top-of-mind. At the forefront of HVAC retrofits and new constructions are fan arrays, sometimes referred to as fan walls or grids. These luggage-sized, modular units can be arranged in a gridlike array, which optimises the balance between energy consumption, acoustics, and low cost.  For owners who still use large, single-fan belt-driven units, a fan array solution represents the best upgrade for future savings and minimum installation hassle.

Fan arrays drive cost-effective change

Traditionally, most air handling solutions in HVAC systems used a belt-drive setup, with a large motor connected to a single fan. However, as EC motor technology has become more cost-effective, reliable, and easy to manufacture, direct-drive plenum fans are the contractors’ new AHU of choice. When you need to replace a legacy air-handling unit, a fan array solution can be installed in days, by only one or two professionals and no heavy lifting equipment. In terms of air quality in buildings, virologists recommend that introducing outside air is the most effective way to fight the spread of airborne particulates like COVID-19. However, this higher energy consumption falls to the AHU responsible for pumping air through a system. A modern fan array system performs at peak energy efficiency and makes buildings as green as possible, while simultaneously offering high standards of indoor air quality.

Single vs. multi-fan systems

Legacy air handlers are usually large, single-fan rotors whose benefits are often outweighed by how difficult they are to run efficiently and upkeep. By placing more compact, electrically commutated (EC) fans together in a grid-like array, air handling units are far less problematic. At Swiss Rotors, we improve upon existing designs with modular fan cells to make installation and teardown much more like LEGO blocks. As a result, you can install, replace, or repair individual units with ease and zero downtime.

Flexibility through fan design

The Swiss Rotors Fan Array pushes any volume of air, at any pressures needed in the moment with a customisable setup. EC motorised impellers operate in parallel, which means airflow can be modulated depending on how many units are in the array, and the speeds at which each unit runs. The system as a whole can reach peak efficiencies and optimal ranges under many varying circumstances and then adjust automatically during operation. A large, single fan unit can typically only turn air volume up or volume down. 

Reliable, redundant, and failproof

Single-unit fans often represent an all-or-nothing risk. Multiple EC fans are more reliable and require less maintenance than belt-drive fans because they have fewer moving parts
If something goes wrong, EC fans also come better equipped with sensor technology to monitor electronically. When one or more units stop operation, the other fans can compensate automatically, making the fan array the best choice for continuous operation.

Smaller space requirements and flexible structure

Distance and spacing requirements for a large single-unit fan can consume a large amount of critical space. When you install a Swiss Rotors Fan Array, each unit is housed within a single walk-in cabinet-size structure that allows a maintenance engineer to easily access every module in the frame. Engineers can easily add plates to block off individual sections, fitting changing requirements on the fly without any additional structures required. 

Easier installation and maintenance

With multiple, smaller fans powered by EC motors, a fan array is much lighter and easier to install without any big equipment. For large single-fan units, you often need cranes or lifts to move a unit. Individual cells and motors by Swiss Rotors can be wheeled through standard doors and elevators, significantly reducing costs and downtime.  Fan arrays also stand upright and cover less floor space than a large belt-driven fan. Cleaning and maintaining these fans–all encased in their own units–is far easier than belt-drives which produce dust and debris during operation. Additionally, periodic cleaning is made easy by each fan’s blade design, which is as simple as sending compressed air through the unit.

Quieter operation

And finally, EC motors are quieter. At most operation speeds, direct-drive EC fans run quietly, specifically in low-frequency octaves that are notoriously difficult to attenuate for rotor technologies. Large, belt-driven units often produce vibrations which can further increase noise output. 

The future of AHUs lies in fan array systems 

Single-fan, belt-driven air handling units are becoming outdated rapidly. In most use cases, a fan array solution yields superior results—in energy savings, maintenance, lifetime operation, and ease of installation. OEMs, manufacturers and contractors prefer proven EC motor technology over traditional, cumbersome single-unit AHUs. As more building owners look to boost energy savings and improve indoor air quality, targeting an upgrade with a fan array should be the #1 priority.