FanSet SolutionAs an OEM, contractors and HVAC engineering companies rely on you to deliver air handling unit (AHU) solutions that combine quality, value and efficiency. Today, the most effective way to do that is by creating solutions incorporating fan array systems. Doing so is likely to strengthen your position in the market and have a positive reputational impact. Read on to learn why. 

What is a fan array system?

A fan array system (FAS) consists of several smaller fans, positioned in a grid format, built into a single wall. The total airflow is calculated by multiplying the number of fans by the airflow capacity of a single fan. Fan array systems are renowned for several benefits. So contractors and engineering firms receiving FAS-based AHU solutions from OEMs are in a strong position to sell the end product to their clients – especially if they are assigned to projects such as ‘green’ retrofits or face restrictive space limits. FAS-based AHU solutions require significantly less energy than traditional large, belt-driven fans. They can also be fitted in smaller spaces and are much easier to install than single-fan solutions. The other main quality they are renowned for is their noise output. Fan array systems deliver lower radiated and airborne noise levels than belt-driven fans. However, they are not the only option available to end-users.

Understanding the pros and cons of single-fan solutions

Despite many advantages, AHUs based on fan array solutions are not necessarily the best choice in every situation. There are several good reasons why contractors or engineers may use a single-fan solution in their HVAC system designs or projects. The right choice for the contractors or engineers your OEM business serves will depend on their specific circumstances. Only a strong understanding of the benefits and limitations of single-fan solutions will enable you to effectively guide your customers to either a conventional air-handling system (CAS) or a fan array system (FAS).

Single-fan solutions are:

  •   More reliable, because fewer parts and lower fan speeds offer a smaller potential for things to go wrong. Contractors and engineers are therefore likely to keep customers happy without having to devote too much time to post-fit maintenance and repairs.
  •   More inclusive, because they are suitable for both lower cost belt drive and direct drive applications. Fan array systems, meanwhile, are only suitable for higher cost direct drive applications with a variable frequency drive (VFD).
  •   Lower in manufacturing cost, because only the main air handling unit casing is insulated and there are no extra costs associated with several motors and wiring conduits.

In contrast, fan array systems are:

  •   Easier to service, with a service professional able to isolate and repair a troublesome single fan with ease. Fan array systems mean less downtime, enabling contractors and engineers to build a sense of trust and confidence quicker and easier than with traditional AHU solutions.
  •   Better for real estate savings, because they take up less space thanks to shorter axial lengths.
  •   Quieter, because the small lattice structure reduces low frequency noise.

Why should an OEM choose a fan array system in their AHU solution?

Fan array systems offer three significant and highly compelling benefits to manufacturers aiming to create and sell a more competitive AHU solution.

1. Efficiency

Fan array systems from Swiss Rotors feature a backward impeller, resulting in higher efficiency levels and lower power consumption. Typically, our fan array systems deliver motor efficiency of more than 90%. In a world ever more focused on lowering its energy use, the inbuilt efficiency of a fan array system attracts many admirers. It is a crucial feature for contractors and engineers looking to equip their customers with an optimal HVAC solution. But it is not just performance where fan array systems are more efficient. They also offer cost savings in both installation and maintenance.

Fitters do not need large tools, heavy lifting equipment to make significant adjustments to doorways. A typical fan array system can be fitted quickly–within one or two days–and without fuss. Ongoing maintenance and cleaning of a fan array system are also easier. The unit is smaller and reached easier. Service professionals can also clean fan array systems simply by sending compressed air through the unit.

2. Redundancy

If a single fan fails in a FAS-based AHU, the unit provides enough redundancy for airflows to continue as required. This feature offers two advantages. First, it avoids the inherent all-or-nothing operational approach of single-fan solutions. If a single fan fails in an array, airflows can continue largely unaffected. The other fans compensate for the faulty one with increased airflows of their own. These compensation calculations are completed and implemented automatically. Second, service professionals can plan downtime for when the demands of a building are at their lowest. Servicing is no longer a time-sensitive, critical issue. FAS-based AHUs remove the pressure to repair faults as soon as they are discovered. The redundancy of a fan array system means building management teams have greater planning options.

3. Flexibility

Fan array systems can be installed in much smaller spaces than single-fan solutions, significantly increasing their potential use cases and making them easier for contractors and engineers to handle and install. End-users can also alter the number of fans in each system to suit their specific airflow requirements.  In a 4×4 grid, for example, initially not all 16 spaces may include fans. Instead, metal plates can be used to blank some of them off. When the airflow demands grow, fitters remove the necessary number of plates and replace them with extra fans. At a stroke, this increases the airflow capacity of the fan array system in line with the building’s increased needs.

The power of EC motors in fan array systems

Electronically commutated (EC) motors are a key part of fan array systems. They give contractors and engineers the chance to offer better solutions to building owners looking to benefit from lower energy costs and optimised energy usage. By combining permanent magnets (for the rotor field) with coils controlled by an electronic ‘commutator’ (for the stator field), EC motors can be electronically managed. And because they can send or receive computer signals, they offer sophisticated control and monitoring features. They also enjoy longer lifespans than DC or brushed motors. EC motors are ideal for fan array systems because they help to unlock each of the three main benefits outlined above. They deliver enhanced efficiency, because they reduce heat exchange, run much cooler and typically use 33%-50% of the energy of conventional motors. They deliver redundancy because the control they offer means each fan in the array system can be appropriately managed. And they ensure flexibility because they are smaller than traditional alternatives. This reduced footprint means that contractors and engineers can easily fit fan array systems on the solutions they create.

How to choose the best fan array system for an AHU

When you design your AHU, it is crucial to consider several factors before you choose your fan array system. What size fan do you need? For example, Swiss Rotors’ direct-driven plenum fans range from 7.5” to 12.4”. At their smallest, they operate at 547 CFM. At their largest, they are capable of supplying 1,942 CFM. Are you looking for as much control as possible? The built-in variable control of an EC motor will provide you with more performance options. Are you looking to reduce energy use? EC motors meet energy efficiency standards outlined by the U.S. Department of Energy. Is noise a critical issue? Fan array systems built with EC motors are both quieter and eliminate the vibrations often associated with large, belt-driven units.

A Swiss Rotors fan set satisfies all of these requirements – and more. The optimised flow control and electric motor commutation deliver quieter in-operation noise levels. It offers increased redundancy, reduced power consumption (thanks to the high efficiency of its backward impellers) and 100% speed control.  The contractors and engineers you supply will also benefit from easier transport and installation processes and simplified maintenance.

Find out more about Swiss Rotors’ fan array systems and discover how they can help you to produce AHU solutions your customers want and need.