1. 43www.racplus.com november 2011
Technology
AthreattoECfans?
Rareearthelements,usedinmanyHVACproducts,haveincreased
in value and this could affect the industry, says AlasdairHowie
n Rare earth elements (or rare earth metals
as they are more commonly known) are a set of
17 chemical elements originally discovered in
Scandinavia. To some extent they belie their name by
actually being relatively plentiful, yet they are still
considered to be rare because of their geochemical
properties and dispersal, which makes them difficult
to mine.
Certain areas across the planet have an abundance
of certain metals or minerals. As for rare earth metals,
China currently has a stranglehold on supply. The
country currently operates over 90 per cent of the
world’s rare earth metal mines. However, it has
reduced its export of the elements as it now wants to
keep more for its own industry, as it plans to build
120 GW of wind generated electricity by 2020 – more
than Britain’s entire electricity production. The wind
farms that it plans to build will account for a full
year’s worth of Chinese production of rare earth
metals (around 100,000 tonnes), leaving other
countries across the world without a supply of
the elements.
Reports suggest that there are alternative sources
of rare earth metals, with mines planned for
California, Australia, Arctic Canada and even
Greenland. However, the environmental impact of
opening mines in areas such as the Arctic and
Greenland must be very carefully considered, even if
it does mean we can produce renewable energy
devices to attempt to reduce CO2
.
In the HVAC industry, rare earth metals are a vital
component of electronically commutated (EC) fans,
thanks to their use of permanent magnets or brushless
DC motors. They boast several advantages over
AC fans such as increasing the efficiency of an
application into which they are connected. The higher
efficiency translates as an energy saving that can be
significant over the life of the product. The higher
efficiency also translates into lower running
temperatures in the motor and bearings, and that
makes a significant contribution to the longevity
of the product.
However, we believe there are areas that need to
be carefully considered when utilising EC technology;
the Ingress Protection (IP) rating of EC fans can be
lower than that of an equivalent AC fan and the
complex commutation electronics (essentially an
onboard inverter) are more susceptible to problems
caused by high temperatures and humidity. For many
environments the relative simplicity and robustness
of the AC motor still makes it the most common
fan choice.
The main issue we have, however, is not with the
technology, which makes an EC motor more energy-
efficient than an equivalent AC fan, but with the
potential difficulty in sourcing rare earth elements.
The technology is being threatened by issues of
availability, lead time, pricing volatility and the
uncertainty of supply. Shortages in rare earth elements
could threaten the future of EC fan technology.
But the good news regarding China is that the
World Trade Organisation has recently ruled against
China’s curbs on export quotas by requesting that
China maintain continuity of supply to trade partners
in Europe and the US.
Price can sometimes be an issue, as EC fans tend
to cost more to produce than their AC counterparts.
Unfortunately, some product specifications are still
decided purely on initial capital cost rather than
whole-life cost, and while this remains the case there
will always be a market for AC fans.
To paraphrase Donald Rumsfeld: there are the
things that we know (EC is efficient but expensive),
there are the things we know that we don’t know
(EC technology is reliant on rare earth elements
whose supply is uncertain and requires that we
second-guess China’s policy on exports of these
elements) and then there are those things that we
don’t even know that we don’t know yet. In such a
climate, is there not cause for some caution? n
Alasdair Howie is marketing manager of Soler
& Palau
Rare earth metals, a
vital component of
EC fans, have been
increasing sharply
in value due to
supply issues