Hi Chris
From reading the reply's looks like this is a little more complex than it first looks. So I have spoken to Geoff Lockwood our Technical Director who is involved in these sorts of regulations all the time. He has forwarded me the following message to post that hopefully should help.
There is not a defined Specific Fan Power (SFP) target within the new Energy related Products (ErP) regulations for fans. The measure of SFP is not a term to define the efficiency of the fan it is a term that defines the energy consumption of a system related to a specific volume flow where a fan or fans are installed. The ErP is a directive that sets out to define the efficiency of many products (not systems), one of which is fans, and therefore uses the standard term of fan efficiency based on air power out divided by electrical power into the motor or drive. There is no cross reference from fan efficiency to SFP.
There is a Fan Manufacturers Association (FMA) guidance note, GN04, that gives explanation to fan efficiency and SFP - http://www.feta.co.uk/fma/downloads/FMA%20GN4%20Fan%20Efficiency-v2.pdf
Specific fan power is calculated by the equation Pe/V, where Pe is electrical power input in Watts and V is volume flow in l/s. So one way to reduce the SFP figure is to improve the impeller and motor efficiency and hence reduce the Pe value. But an alternative way to reduce the SFP figure is to reduce the resistance to the flow of air in the system; air power is volume flow times pressure loss, so keeping the same volume flow and reducing the pressure loss reduces the air power and a reduction in the air power leads to a reduction in power input and therefore a reduction of the SFP figure.
We find that the most significant way to reduce SFP figures is to ensure the fans are selected to operate at peak efficiency, are installed correctly (avoiding losses) and that the system loses are reduced through good system design. There is an joint FMA and CIBSE application guide that gives good advice - http://www.feta.co.uk/fma/fma-01.htm
There is a new International Standard, ISO12759 – fans – efficiency classification for fans, that has been produced to support the ErP regulations. This explains how the fan efficiency is calculated, relates it to the efficiency grades referred to in Annex I table 1 and 2, and gives worked examples. It has been approved by ISO members and is likely to be published January or February 2011. The FMA has already given some training to the industry and is likely to provide further advice via seminars.
The ErP fan regulations have been approved by the EU commission and are expected to be published this month.
Regarding the impact we, ebm-papst, believe about 30% of the products currently on the market will not meet the requirements, typically fans driven by low efficient shaded pole motors.
Regarding the comment ‘only simple AC motors are included’. Assuming that this comment refers to the ErP regulations for fans, then this is not a correct assumption. All electric motors types driving fans are within the scope. In general DC motors and EC motors easily exceed the limits. If the reference is to the ErP regulation for motors, then yes this is true and the EU has missed the point. Those regulations are for motors >0.75 kW and AC induction motors only.
I would like to point out that the fan regulations considers fans/motors with integrated drives/controls and gives them an advantage.
He has also told me that the ISO standard can be found here
And that it should also appear on the BSI site soon.
Thanks
Paul
