Fan coils
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Up-to-date solution for outdated FCUs
With a greater emphasis being placed on lowering running costs whilst minimising emissions in modern buildings, Jon Freeman at Ability, part of Glen Dimplex Heating & Ventilation, looks at how contractors and manufacturers can collaborate to take advantage of the benefits that the latest advances in fan coil units can offer for essential building refurbishments
The ability to control the output of a unit to more closely match the actual
requirement of the occupied space seems such an obvious one, and has led to the significant reduction in energy consumption that modern control systems and fan motor technology allow.
Modern advancements E
xpectation of comfort where we live and work has driven the intensity of use of climate control systems in multi-residency, offices, hotels and other commercial premises, increasing energy use, especially by older, less- efficient heating and cooling systems. At the same time, the past decade has seen the UK commit to a number of obligations to reduce carbon emissions and tackle climate change. A key consideration is the Government’s Clean Growth Strategy, required under the Climate Change Act, which last October set out the next steps to reduce Britain’s 1990 carbon emissions levels by 80% by 2050. To meet these targets the responsibility doesn’t stop with the construction of new energy efficient buildings, but requires significant reductions in carbon emissions from existing buildings. This is adding pressure on facilities managers, specifiers, contractors and their supply chains to make considerable improvements in building insulation, heating, ventilation and air conditioning (HVAC) systems, as well as plant management. Heating, hot water and cooling systems account for around 60% of all energy
consumption – which means upgrading outdated and poorly maintained HVAC systems has a huge role to play in tackling emissions, optimising efficiency and reducing operating costs.
Fan coil units (FCUs)
Fan coils have been providing a cost-efficient way of heating and cooling a building for over 40 years. Comprising a coil, filter and fan/s, FCUs are used to control the temperature in the localised space within which they are installed. Traditionally they incorporate AC motors set to a design air volume, with a manual on/off function and simple thermostatic temperature control, which enables water flow to the coil using a control valve. Early improvements in product efficiency were the introduction of a
transformer to permit three fan speeds, and the implementation of control strategies to govern water flow through the coil depending on the space requirement.
30 July 2018
The pace of development has increased dramatically during the last 20 years, with the single largest opportunity for improving energy efficiency coming from controllability – in particular from the introduction of EC (electronically commutated) fans. The immediate benefit is increased efficiency over an AC motor, however the capability to provide infinitely variable air volume has enabled control strategies to become far more intelligent. The additional flexibility afforded by improvements to valve and actuator technology, the ability to vary air and water flow through the FCU, whilst being able to accurately measure the space, supply and return air temperatures, means that demand relates to real time requirement, rather than a preconceived design condition.
Energy efficient retrofit
For anyone working on refurbishment programmes, replacing an ageing fan coil system with the more efficient products available now offers significant reductions in running costs and carbon emissions. It also enables the introduction of more enhanced control systems, to further improve these savings. With a 60% energy reduction achieved by switching from AC to EC fans, replacing a poorly maintained, outdated system with a modern alternative should see occupants benefitting from savings in excess of 80%. Replacing tired fan coils can be the quickest and simplest way to rejuvenate a building’s HVAC system, and is proving to be the preferred method for full building refurbishments. However, if a building is still occupied a full system refurb is disruptive and
also requires the disposal of entire units which can mean a lot of material being sent for recycling.
A refreshing alternative
Having been the forerunner of EC FCUs over 15 years ago, Ability has always seen the benefit of introducing modern technology and adapting systems to offer customers the opportunity to make the most of the controllability it affords. It was this approach that led to one of our customers replacing an AC system with EC fans within two years of commissioning. The incredibly short payback period on this project led us to focus on what
could be done to enhance an existing unit rather than simply removing it. With the biggest potential for energy saving coming from EC fans and the
advances in control capabilities, Ability began working with customers on alternatives to full product replacement. This flexible approach to a specific customer requirement saw a challenging
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