Large fans save on heating energy costs

Fans are often regarded as excessive energy users rather than energy savers, but companies using MegaFan's 24ft high volume low speed fans reported gas bill savings exceeding 50%.

A 24ft diameter, NASA inspired fan design is saving energy for specialist materials manufacturer Wardle Storeys at its manufacturing facility in Earby, Lancashire, UK.

The fan is always running at the optimum speed managed by an innovative control system supplied by Mitsubishi.

Companies using MegaFan's 24ft HVLS (high volume low speed) fans are reporting savings in excess of 50% on their gas bills in the winter.

Said to replace up to 25 conventional fans, yet costing the same as running one, the HVLS fan is based on a NASA developed aerofoil blade design Traditional, small fans run at high speeds to increase air displacement.

But what the developers of HVLS fans said that the volume of air moved through a fan is of no real significance.

Instead, it is the down-stream effects that are important.

A turbulent, high velocity air jet dissipates very quickly, so can only have very local effects.

By contrast, the key to the success of MegaFan's HVLS fan is the fact that it is designed to run at low speed, recirculating the huge reservoirs of hot air that frequently get trapped high up in large buildings and warehouses, unable to escape.

The developers of the HVLS fans recognised the energy saving potential of recirculating these warm air pockets that would otherwise be wasted.

HVLS fans use an aerofoil blade design that has the physical properties needed to maximise its ability to capture and circulate large volumes of air.

The air output velocity was carefully calculated to optimise the air movement effects.

Wardle Storeys' manufacturing facility produces specialist technical foils, acoustic materials, fabricated components and related products.

These products are used across a wide spread of markets, including automotive, contract upholstery, building and construction, medical and stationery.

A recent project saw three HVLS fans installed at the Earby facility.

The fan assemblies were clamped to an RSJ, with power taken from a busbar and a communication cable running between the fans and the control panel.

The control panel itself was developed by MegaFan and Mitsubishi, allowing the variable speed drives on each fan to be individually controlled, with speed and direction adjusted as required.

The control panel features a touch screen HMI from Mitsubishi's E1000 range, giving easy operation and visualisation of the fan network.

The HMI has a high resolution TFT display and a touch screen interface, giving operators direct access to all the fan functions.

In winter, setting the fans to run at a low speed of around 30 rev/min draws vast quantities of warm air into the fan from reservoirs trapped in the ceiling, and gently pushes that air downwards.

Wardle Storeys says it was able to reduce thermostat settings by 4 deg C, and switch off one third of the heaters in the building, while still maintaining a comfortable working environment.

This energy saving contributes to direct cost savings in the heating bill.

* Summer - in the summer months, increasing the fan speed to around 54 rev/min generates a pleasant cooling breeze, unlike the localised, intrusive blasts of air from conventional, smaller fans.

Mitsubishi Electric energy spokesman Jeff Whiting said: "One of the biggest challenges facing industry today is rising energy costs.

This can have significant negative impact on a company's financial performance, biting deeply into hard earned profits - and all at a time when shareholders are demanding ever better returns on their investment".

He continued: "One of the ways of reacting to this challenge is through both innovative thinking and effective technologies.

The installation at Wardle Storeys shows exactly what can be done".

The installation at Wardle Storeys shows how the combination of MegaFan's HVLS fans and Mitsubishi's control systems makes good business sense for companies, enabling them to dramatically increase the comfort of workers whilst at the same time significantly reducing their energy bills.

Savings of 50% in energy bills are regularly reported, and one study showed up to 84% energy savings when an HVLS fan was compared to five conventional fans.

Despite its size, the HVLS fan is economical to buy and inexpensive to run.

While the fan itself may be massive, the motors running them are certainly not, rated below 1.5kW in size.

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