34 Air Handling Units Setting the standard


In a dynamic and competitive ventilation market, Dene Kent, technical director at Fläkt Woods, discusses how the design and specification of air handling units is changing, and highlights the benefits of a shift towards more standardised products.


ACCORDING TO recent research, the UK ventilation and air conditioning industry is worth an estimated £1.03bn. This might sound like a significant sum, but it doesn’t tell the whole story of a market that is directly linked to trends in construction. Revisit the heady days of 2008 in a pre- credit crunch Britain, and the market was worth almost £1.2bn, which demonstrates a contraction of approximately 14%. However, this reduction in sales volume hasn’t stifled the development train for manufacturers of ventilation equipment. And, one product group in particular that has made impressive headway in recent years is air handling units (AHUs). The innovation of the AHU market has been stimulated by increasing health, safety and energy efficiency legislation. Coupled with revised Building Regulations and environmental legislation, the market has started producing new products and systems which offer an alternative approach to specification.


Traditionally, AHUs have been supplied as a bespoke package, taking into consideration the individual factors and requirements for a project.


But more and more manufacturers are starting to offer ‘off-the-shelf’ options, which can be just as effective as tailor-made products.


In some cases, they can prove to be the more pragmatic choice, resulting in improvements in lifetime energy efficiencies, lead times and future proofing. Taking a more standardised approach has often been seen as the cost effective option, where internal component quality is sacrificed to maintain a competitive price point.


This can still be true for some products on the market, but the latest incarnation of high quality standardised AHUs, such as the eQ Prime from Fläkt Woods, are changing the marketplace.


These types of unit can easily compete with bespoke units and yield a number of benefits for consultants, contractors and clients.


One of the more practical elements of standardised AHUs is a common base frame, which is designed to simplify installation and also reduce on-site costs. Such a setup also allows a unit to be delivered ready mounted on a single frame, with the option of separating it if necessary. In addition, if further components are required, for example silencers or dampers,


ACR News April 2014


the modular system can be easily extended. Aside from the practical on-site elements of a high quality standardised product, there can be a number of energy efficiency advantages.


By taking a comprehensive approach to the design of an AHU, manufacturers have identified key areas that can improve performance. One such area is filter systems. Although they are usually the least expensive and simplest components, they can be the most energy hungry. In an average commercial building, around half of the bill is for the HVAC system, with approximately a third of that directly related to the air filter. So, specifying an AHU with a high quality filter that has the correct efficiency levels and pressure drop can offer significant energy saving benefits.


Other performance measures that are important aspects of standardised AHUs include specific fan powers (SFP) and motor efficiency.


Since June 2011, all motors


with an output rating of between 0.75kW and 375kW have had to meet the IE2 standard of energy efficiency.


The second phase – scheduled for 2015 – will further improve these standards with IE3 motors eventually becoming the minimum requirement.


This is particularly important for the specification of AHUs, as the efficiency of motors can have a major impact on running costs.


Some low cost products might only provide the minimum IE2 requirement, but doing so can be a false economy, with the initial saving easily outweighed by the lifetime running costs.


For this reason, some manufacturers such as Fläkt Woods are incorporating the latest IE4 permanent magnet motors into its standardised range.


These provide the highest energy efficiency savings, while also helping to lower SFPs and electrical energy costs. The final benefit from high quality standardised AHUs is integrated control


units. These allow a consultant to specify a system which is pre-programmed for optimum efficiency and reliable operation. And for contractors, integrated controls allow the commissioning element of a project to be a quicker and more efficient process.


For the medium term forecast, the UK ventilation and air conditioning industry is estimated to have moderate annual growth rates of 2%-3%, with the market size expected to reach around £1.13bn by 2017. It might not reach the heights achieved back in 2008, but this would still represent a healthy increase.


Of course, the most notable difference to 2008 is not the size of the industry, but the development and innovation of new products such as standardised AHUs. If manufacturers continue to take a holistic approach to high quality ‘off-the-shelf’ units, and consultants and contractors embrace the benefits on offer, the long term forecasts for the industry look extremely promising.


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The eQ Prime from Fläkt Woods.


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