Is a roof-top wind farm for you? They’re not
for everybody, but it could very well be, for some, the first step toward
a greener lifestyle and energy independence. This article will
supply some groundwork to help you decide. Along the way, I’ll
debunk some common myths surrounding roof-top wind generators (RTGs) and
describe some features built in to most units that further enhance the
sleepability and general pleasure of experiencing life with a roof-top
wind generator, or two, or three, or...
First off, though, RTGs make noise. It’s a
fact, as it is true, more or less, for all rotating machinery. Like
people, some noise is just more pleasing, more interesting, and overall
more fun to be around. Take music, for example. In regards to nature
sounds, you’d be hard-pressed to read a novel and not find a reference to
some specific nerve-calming sound derived from the wind. Wind sounds
seem a nice part of the human experience. Except perhaps for Hilda.
With a slightly increased beat of my heart, still,
even after 25 years, I recall with a strange fondness when I was secretly
in love with Hateful Hilda the Widowed Waitress. It was rumored her
husband had died of the bloody flux. I met her at the Moose Lip Café
where she was doling out late-night food and coffee, some free advice, and
psychiatric amendments to anyone in need, even those not in need.
She was widowed way too young and it seemed to have an ill effect on her
disposition. But Hateful Hilda was a good listener. One ear
was much bigger than the other so she couldn’t help hearing from that side
even if she didn’t want to. I suppose, because of that ailment
nothing was ever in harmony for her. She once flat out told me she
hated music. All music. Gasp! My best guess is that H.H.,
hardy as she was, would NOT be a very good candidate for a roof-top wind
generator. But she was one-of-a- kind! Alas, she married again
shortly after I met her... to someone else, and moved away.
Wind gennys, as they are affectionately known, are
dynamic. I think that’s why we like them so much. You can
watch them work; hear them sing. They transform seamlessly from a
whisper to a song, to a whine and a howl. And they will do it all
day, all night whenever the wind asks. To me, it’s the sound of
electrons filling a bank of batteries for later use. What I
previously had to purchase from a soot-belching, highly impersonal
conglomerate, one adept at splitting apart unnaturally high concentrations
of already unstable nuclei, now comes my way on the wind along with a
song...without cancer, without radiation, and most noticeably, without a
monthly bill. If I don’t listen to the song, it rewards me with
electrons and a symphony anyway.
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Over the course of several years, I installed two Southwest Windpower
Air-X 400 watt wind turbines and a Mallard 800 watt wind generator on my
small homestead using a roof-top mounting instead of towers.
The two Air-X’s have a 46-inch rotor and come to life when
the wind speed reaches 7 mph. The third wind generator, the odd
ball, the Mallard 800E, lies dormant until 9-10 mph. It has a 5-foot
rotor with 6 blades. Plenty of torque but it seems to lack in power
over most of the wind spectrum prevalent here, (but read on)!
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7-10 MPH
At 7 to 10 mph, the Air-X gennys spring to life.
With a barely audible, low-pitched, bearing-rumble, sounding more like
Elvis starting up Blue Christmas at 33-1/3. The rotors turn
ever-so-slowly, almost begrudgingly. If you listen closely, a slight
whoosh of air can be heard, although it’s usually drowned out by the other
sounds of life in and around the house. At this slow speed, each rev
of the rotor can be discerned and matched with a spot in the air, perhaps
corresponding to a relative flat spot on a ball in the bearing. It’s
more noticeable if I’m up in the loft or outside but hardly so in the
living quarters.
No power is generated at the lower end of this regime
as the output of the alternator is way below the 12 volts of my battery
bank. A not-so-convenient red LED light is positioned on the
underbelly of the Air-X that illuminates when the output exceeds the
battery voltage and the unit starts charging. Depending on the state
of the batteries, as the wind speed increases to around 10 mph, the LED
comes on and the Air-X’s begin to feed the batteries a breakfast of
electrons...and the fun begins.
Here the internal alternator starts to load up and
the low-frequency bearing-rumble gets louder. No more Elvis, he’s
dead. It sounds more like a bass cello whose fat strings are set
vibrating from the gentle strokes of nature’s bow - mellow, vibrant,
well-plucked. Shortly, the rumble is overshadowed by an increasing
whooshing of air, a soft whisper that gently touches the ear, plainly
audible now from inside the house. At the upper end, around 9-10
mph, the whoosh is more like the sound of a summer breeze whistling
through a slightly-open, screened window. Sometimes I think to
myself that perhaps a delicate honeysuckle fragrance should be riding in
on the breeze but abruptly I remember that I’m a bachelor, on a farm with
livestock, so...
Suddenly, my
thoughts are interrupted.
On
the other side of the house, the east side genny
kicks in,
and now there’s two part harmony adding dimension and flavor to a freshly
nucleated symphony of wind.
The Mallard,
the bigger brother, wakes up sluggishly around 9-10 mph. Noticeably
absent is the bearing rumble sound, for he seems to be built of stronger
stuff. Quieter as well. The Mallard’s slower rotational speed
results in a lower-frequency, lower-pitched air whoosh that adds depth and
bottom-end to the slowly growing wind song. However, at this stage
of the game, it is positioned too far away from the symphony to play a
major role.
Everything at
this wind speed is slow, soft, leisurely. The low wind speed fails
to keep the rotors moving for any length of time so the music is
inconsistently punctuated with lots of empty space. Interesting, but
it leaves you asking “Is that all there is?” Output isn’t even worth
measuring, but it’s there.
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I installed a homemade power panel right by the ladder into
the loft. It consists of a volt and ammeter for each device (including the
solar panels) and stop switches for the wind generators plus a cut-off
switch for the solar end of things. The gauges allow me to monitor the
instantaneous voltage and current output of each device as well as the
state of my batteries. The stop switches are designed so that I can shut
down a generator in case of high damaging winds or for maintenance. The
gauges are an automotive item and come equipped with a small bulb that,
when I switch it on, acts as a convenient night-light. |
