Wind Turbine Cooling System Improvements

This week we discuss cooling system patents, including Siemens
Gamesa's method for creating air channels for better temperature
control, Goldwind's predictive temperature moderating, and GE's
adjustable power output based on component temperatures. Fill out
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YouTube channel here. Have a question we can answer on the
show? Email us! This is Power Up, where groundbreaking wind
energy ideas become your clean energy future. Here's your hosts,
Allen Hall and Phil Totaro. Allen Hall: Phil, this episode of Power
Up is going to focus on cooling. And as wind turbines get bigger
and bigger, thermal controls are becoming more important. You need
to make sure that there's no thermal runaways, and with the amount
of power. 8, 10, 12, 15 megawatts going on inside of some of these
nacelles. You're seeing a lot of patents and innovation around
cooling, and this first one is from Siemens Gamesa, and it has to
do with the generator itself. And the patent describes a cooling
system for the generator that places air channels to better control
temperature. Within the generator. Now, the key feature includes
the magnet elements arranged in rows with groove like recesses that
allow for targeted airflow between the components. Now, that design
creates multiple cooling paths with gaps somewhere between like a
half a millimeter and ten millimeters wide that enable better heat
dissipation. So, obviously Siemens Gamesa sees the future, which is
thermal control in a generator, because if you have overheating in
generators That can be quite expensive to fix, so they're trying to
address it up front, Phil, with this basically airflow pattern.
Phil Totaro: Yeah, and, and as you mentioned, not only are
generators getting bigger but particularly for offshore, the
operational efficiency matters a lot. and how you control both the
flux density and efficiency of the generator, balanced against how
you have to cool the thing to maintain the kind of an air gap that
you need in order to get the efficiency you want. It, it just
throws these thermal engineers into complete chaos most of the
time. So the way that they're architecting this is so that you can
control the airflow in those channels in between the, the magnet
holders to prevent hotspots. For the long term, if it keeps
happening and you keep getting the hotspot, it can actually cause
thermal degradation in the magnets and in The, the generator
structure itself. So again, in order to maintain kind of peak
operational efficiency, cooling becomes a a critical component to
that. Allen Hall: Our second patent is from Goldwind and it is also
focused on cooling up and then the cell. And it. Is an idea that is
wrapped around really a sophisticated coolings control system that
uses predictive temperature monitoring to optimize cooling. And as
you can well imagine, as these generators get bigger, there's just
a lot of nooks and crannies and you need to be able to monitor the
hole in the cell area for temperature increases and to control it.
Well, this system connects a cooling device and a yaw controller to
a frequency converter that controls the operation based on the
predictive temperature. Temperature thresholds. Now the key
innovation is ability to anticipate when cooling will be needed and
by calculating future temperature profiles and allowing a more
proactive reaction to that temperature control. So they're, they're
using a lot more information to predict where the temperatures will
be and from what it sounds like, Phil, is they're kind of yawing
the turbine out of peak power slightly. to control the temperature
so they don't have a thermal runaway. Phil Totaro: Yeah. And what
makes this innovation really unique is, as you mentioned, the fact
that they have it connected to the frequency converter itself,
because what they can do with that and how that's going to impact
and influence The temperature prediction is they can look at
frequencies over time and see if there's, a substantial increase or
decrease in, in the frequency on the converter and use that to kind
of inform this, this predictive model that they're going to use to
determine. How much they need to kind of, I've likened this to,
you're, you're flat on the accelerator in your car or something,
and then you kind of let off a little bit to, to just let
everything cool down. And then, you, you step back on, on full
throttle once your, your brakes and your bearings all get back down
into a temperature range that, that's, not going to cause your
wheels to explode. It's kind of a similar principle here with being
able to connect this first to the frequency converter and use that
to influence the, the model and the signals that are, that are
being generated. And then secondly, as you mentioned, connecting it
to the yaw system is also very unique in that they want to be able
to just angle the turbine slightly so that, as you mentioned, it's
not on peak power 100 percent of the time because that can cause,
thermal degradation. So it's a, it's a really clever idea. I like
it. And our Allen Hall: third patent is from GE Renewables over in
Spain, and the patent is very similar to the Goldwind one,
actually. And it's a method for dynamically adjusting the wind
turbine power output based on component temperatures. And in this
particular case, they're, instead of just using ambient temperature
to determine the power decisions. So in Spain it can get quite hot,
or in India it can get quite hot. Instead of just monitoring
outside temperature, internal temperature inside the nacelle around
the generator, they have a system to monitor multiple component
temperatures. And then you have a thermodynamic model that predicts
what the temperature will climb to. And in this particular patent,
they also talk about derating essentially the turbine, slowing it
down, let everything cool down a little bit and stabilize so it
doesn't have a thermal runaway. So the GE approach is a little
different in that they're looking at basically sensors that
probably already exist in the turbine and using that knowledge to
then create a thermodynamic model. So the idea is similar, Phil, to
what Goldman was proposing. Phil Totaro: Yeah, similar, but what GE
is specifically talking about is how you're, you're establishing
the maximum power set point. And so that's not something that
Goldwind had contemplated in theirs. And what GE is trying to do
with this is ensuring that As I, as I mentioned when describing the
Goldwyn Patent, if you, if you liken this to, keeping your foot on
the accelerator in a car, what GE's doing is they're, they're
controlling when you let off and, and put your foot back on, but
normally how a lot of companies do it is, you, you, Let off the
accelerator and in the case of a wind turbine, you're kind of
derating down to the point where the thermal sensor triggers, a
below threshold kind of thing. And then, you can ramp power back
up. What GE is specifically doing is they're going to They're using
the temperature whether it's thermocouples or other, temperature
sensors that are, that are monitoring the, the components in the
turbine, they're using that to determine the, the maximum power set
point. So that at all times they're outputting as much power as
they possibly can. They're not just letting their foot off the
accelerator. They're. Completely, and then putting it back on,
they're basically throttling back a little and, but still giving,
their, their customers basically of, of their wind turbines, the
maximum amount of power output that they can. Allen Hall: Does that
create a hunt and peck situation for the turbine that it's going to
be yawing quite a bit to maintain that peak power without Phil
Totaro: thermal runaway? They can tune it. to the point where it's
not going to be as much hunt and pack and cause a lot of issues
with the Yaw system. To be blunt, I haven't actually seen whether
or not they've implemented this yet. So we've, we've kind of marked
this down as something that we hope they explore at some point in
the future commercially, because I think it'd be a really clever
addition to their, their technical repertoire. And something that's
probably, desirable. bit of functionality for, an asset owner or an
operator to, to have is, keeping the turbine's maximum power set
point at literally the, the maximum it can possibly be at all
times. While maintaining the, the thermal regulation on all the
components in, in in the nacelle. Allen Hall: That's the key to
operating a wind turbine. You can make one part of the turbine more
efficient, but you have to look at what the downstream effects are.
And if you start, Damaging yaw brakes and yaw motors. It may not be
worth it. So it's a real trade off. It's, it's complicated. Phil
Totaro: There's, there's always design compromises whenever you're
doing any type of system optimization, particularly around
controls. And as we talked about a few weeks ago on, on PowerUp,
you can. You can over optimize a little bit too much, and have way
too many controls doing way too many opposing things. So, this is
one of those where it requires dependence and interaction with the
mechanical system. So that's something that in order to not induce
wear on the turbine, that's probably something that takes a good
degree of precision, and a good degree of importance too when
again, it comes to both the, the engineering side of it and the
operation side.