Yes, the annual Ability Pie and Pint event starts today / 23rd & 24th Nov

Follow this link to get details and directions

 

 ...

World Projects

Low SFP Fan Coil Units - Energy Efficient Systems

ETL Fan Coil Listing

Low Specific Fan Power is the current industry buzz, but it requires some forward thinking to get and then keep your SFP's low.

The SFP (Specific Fan Power) of a fan coil is measured in W/(l/s). This is Watts per litre per second of conditioned air moved.

The Watts element of this formula is the Watts consumed by the motors alone. So while the controller and other electronic components on the unit may themselves take power, they should not and do not figure in the calculation.

The Watts consumption is also influenced by the static pressure against which the fans are operating. Most UK specifications detail a static pressure of 30Pa and so when fan coil manufacturers quotes their own unit specific SFPs in a tender quotation, they should be quoting their SFPs at that pressure.

The reality on site however is that the static pressure will not be 30Pa and most 'freshly installed' fan coil units are probably operating against more like 10-15Pa. This is especially so when you consider that most EC fan coils are also operating a VAV (Variable Air Volume) strategy and so the air volume generally could be 30% down on the specified design value.

There are three points to note here.

  • Fan coils only return their specified SFPs when the filters are relatively clean. The minute the filters start to dirty the SFP will rise. Ability Matrix Fan Coil Units have a feature which will measure the 'Dirtyness' of a filter and report it's condition through to the Facilities Management Team. Please see our article on this.

Be Careful

  • Some very low SFPs 'Banded about' are not always at the specified 30Pa but at the operational pressure of 10-15Pa

Also

  • SFPs Based on Watts/(litre/second) can be misleading when trying to make a proper comparison between the electrical energy consumed of one Fan Coil product and another. This is because whilst the Watts consumed by one product might be lower than another, if the Power Factor of that products is worse, the overall power consumed in Volt Amps (VA) may also be worse. When evaluating two products properly, one alternative which may give a clearer indication is perhaps Volt Amps - VA/(l/s).

Fan Coil Clean Me

The UKs regulatory limit for SFP for Fan coils currently stands at 0.6 Watts/(litres/sec)

HEVAC Positional Statement on SFP's