The latest electronically commutated fan technology can offer up to 30 per cent lower energy consumption compared to AC fan technology, says Geoff Lockwood.
A building's carbon efficiency is now a key factor to consider when specifying products in both new build and retrofit projects. With the UK's Carbon Reduction Commitment Energy Efficiency Scheme (CRCEES) taking affect from April 2010, requiring a 25 per cent reduction in the carbon footprint of a building, and government regulations, such as the Energy Related Products Directive (ErP) which will set high minimum efficiency ratings for fans, the changes are set to impact on many organisations.


Implemented primarily to encourage businesses to reduce their greenhouse gas emissions, CRCEES is applicable to firms with an annual electricity demand of over 6,000 MWh. These organisations are required to purchase annual allowances for each tonne of CO₂ they emit and with the cost of CO₂ at £12 per tonne this will encourage organisations to assess energy usage and employ more cost-effective, energy efficient environments.

These regulations will mean that contractors and consultants will increasingly need to be aware of new products that help to reduce a building's energy consumption at every level. This constant adjustment and desire to achieve further energy efficiencies will ensure that current and future building legislation compliance is met and help occupiers meet their current CRCEES obligations.

With one third of a building's carbon emissions created through applications such as heating, ventilating, air conditioning and other air movement applications, significant savings can be made through use of the right technology, materials and techniques. EfficientAir, a company that delivers air conditioning inspections, hvac energy surveys and energy saving projects has shown that hvac systems consume between 40 and 80 per cent of a building's energy. Taking this into consideration, and combined with the introduction of the CRCEES and ErP in 2013, hvac products are increasingly being scrutinised to provide additional energy savings.

Improving energy efficiency will be vital in reducing the financial impact of the CRCEEC and considerable savings in energy consumption can be made in most buildings by specifying the installation of or replacement of traditional equipment with the latest technologies, such as substituting AC fans with electronically commutated (EC) fans.

Traditional fan technology predominantly uses AC motors and is used across a wide range of services. The latest EC fan technology can offer up to a 30 per cent reduction in energy consumption compared to AC fan technology and therefore can have a significant impact upon energy usage and the carbon footprint of building services across a wide range of applications and environments.

Thus, the specification of fans using EC technology reduce the energy allowances required and that means that investment in such technology can provide impressive rates of return.

Range of services

Like AC fans, EC versions can be used in a range of services including air conditioning, ventilation and heat recovery, heating, refrigeration, humidification, condensers and evaporators.

Many EC fans have been designed to provide like-for-like replacements of existing products, allowing simple replacement and installation across a wide range of applications. This makes this technology ideal for use in retrofit and refurbishment projects that are currently dominating the construction sector.

There are fundamental differences between the two technologies. Traditional motors comprise two major parts - the rotor and the stator. Rotation occurs as a result of a magnetic field generated between the rotor and the stator. In AC motors, this magnetic field is generated by applying a current to copper stator windings. Losses in the copper windings consume energy. In EC motors, the magnetic field between the rotor and the stator is generated by permanent magnets on the rotor. Therefore, as no external current is required to produce the magnetic field, no energy is consumed.

Unlike AC fan technology, EC fans are controlled by integrated onboard electronics. These not only supply the commutation, but also ensure constant motor efficiency at any operating speed. They provide simple open or closed loop speed control, precise control of fan speed against system demand, master/slave operation of multiple fans against programmable parameters and direct connection to bus networks and BMS systems.

As a result, fans using EC technology generate less waste heat, are quieter and can be controlled and monitored more accurately.

With the present CRCEES regulations and anticipated ErP changes taking effect in two years, it is expected that about 30 per cent of all currently available fans will no longer satisfy the new regulations. It is evident that carbon reduction requirements will be more stringent and thus it is high on the agenda.

EC fan technology can already achieve levels that are expected to be set in 2015 through the use of its state-of-the-art technology. It has been developed to answer the requirements of the built environment, both today and into the future.