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World: r3wp

[Tech News] Interesting technology

GrahamC
23-Apr-2011
[6003]
well, because they spin so fast
Kaj
23-Apr-2011
[6004x2]
That's the case with CPU fans, as well
Size matters. The bigger the better
GrahamC
23-Apr-2011
[6006x4]
to shed energy ( so that they blades don't fall apart ), they undergo 
fibroelastic shudder
which creates vortices and lots of noise
flutter
here's a picture from the roof .... http://www.compkarori.com/images/karori403.jpg
Kaj
23-Apr-2011
[6010]
I've been riding my bicycle under those really big ones in a big 
storm. Pretty impressive
GrahamC
23-Apr-2011
[6011]
I thought I would be far away from the neighbours .. but clearly 
I was not
Kaj
23-Apr-2011
[6012]
It looks quite close. The noise of small fans is very high pitched. 
It annoys the hell out of me, too
GrahamC
23-Apr-2011
[6013x3]
I was going to short it during the night which basically puts a break 
on the whole thing.  And leave it going during the day
Even with the turbine shorted .. it still spun quite fast in a strong 
wind
One of these days I'm going to cover my roof in Photovoltaic panels
Kaj
23-Apr-2011
[6016]
The longer you wait, the more efficient they become :-)
GrahamC
23-Apr-2011
[6017x3]
True ... there's a lot of research in this area
I think you can even create tiles of the PV panels and use them to 
cover the roof
And I think I've seen flexible ones that can wrap around objects
Kaj
23-Apr-2011
[6020]
You could have clothed you wind sculpture with them ;-)
GrahamC
23-Apr-2011
[6021x4]
To maximize the benefits from PV panels you need to track the sun 
and not the wind!
Most passive sun trackers use an inert gas which vapourises and condenses 
elsewhere changing the balance so that the whole thing pivots with 
the change in weight redistribution
A bit like a sun flower I guess
or a tulip?
Reichart
23-Apr-2011
[6025]
I'm planning on VAWTs.  Make little to no noticible noise.  Work 
from any direction, so less parts.
GrahamC
24-Apr-2011
[6026x2]
And sadly the Savonius design is very inefficient.  I helped my child 
build one for her science fare though .. still got it.
I looked at these years ago http://www.windside.com/technical.html#WS-4C
but deemed them to be too expensive
Reichart
24-Apr-2011
[6028]
Electricity in Maui is .33 per kw...  All alternative power options 
are "worth it".
Maxim
24-Apr-2011
[6029]
ouch... here its .075/kwh
GrahamC
24-Apr-2011
[6030x2]
With all that sun .. I'd go for PV panels
Pity we can't harness the power of tsunamis
Geomol
25-Apr-2011
[6032]
It could be interesting to compare prices of electricity around the 
world. Also the prices, Reichart and Max give, are they total prices 
incl. all vat, tax and distribution?


In Denmark, where I live, we pay around DKK 2.00 in total per kWh, 
that's USD 0.39 per kWh. 1/5 of that is vat (danish: "moms"), almost 
half is a special tax on electricity, and the rest is split in actual 
price of electricity and its distribution. See pie diagram here:

http://www.dongenergy.dk/privat/El/omelprisen/Pages/om elprisen.aspx


In Denmark 25% of our electricity comes from wind mills, many located 
in the ocean. If some of you pay 0.075/kWh, that seems very cheap.
Henrik
25-Apr-2011
[6033]
Geomol, you have perhaps noticed, there is a discussion of the merit 
of the wind mills, due to the enormous expense on building and maintaining 
them.
Geomol
25-Apr-2011
[6034x2]
I haven't really ... well, I remember hearing something from time 
to time in the news. I just pointed it out, because that might be 
valid information when comparing the prices.
Is the price, I gave, about the same in your area, Henrik? (I had 
no idea of the price here actually, so had to look it up.)
Henrik
25-Apr-2011
[6036x2]
I think ours is perhaps 1.50 to 2 kr per kWh. Perhaps lower.
The brilliance of the electricity tax, is that it doesn't make economical 
sense to switch to solar or wind, since it's not a tax on the source, 
but on electricity in general. The best way is probably to have your 
own solar installation and use the government's program for allowing 
you to sell electricity back to the power plant by having it hooked 
up to the grid instead of using it to supply your own house. Each 
user is allowed up to a 6 kW installation.
Geomol
25-Apr-2011
[6038x2]
I just noticed, we also have to pay subscriptions, DKK 12.50/month 
for el, DKK 67.50/month network (electricity network, I guess). That 
USD 15.57 per month in subscriptions.


So to get full price, I should figure out, how many kWh, I use for 
a whole year, times price per kWh, add subscriptions and divide by 
kWh, then I have full price per kWh.
Thinking pure economy, it pretty much sucks to live here, don't you 
think, Henrik? ;-)
Henrik
25-Apr-2011
[6040]
Geomol, I always have thought that in 30 years, when our tax rate 
is 80-90%, we are the ones who will need food aid from Africa, once 
they launch a resource based economy.
Geomol
25-Apr-2011
[6041]
That may very well happen.
Gabriele
25-Apr-2011
[6042]
For those interested into energy policy: http://www.withouthotair.com/
Maxim
25-Apr-2011
[6043x2]
the cost of windmills energy depends on the quality of the winds. 
 they can be amongst the most efficient power sources because the 
very low initial cost and upgrade costs.  ultimately, when we'll 
know how to harvest the sun properly, probably through chemical photosyntesis(nature 
is rarely wrong)   every other energy source will seem "dum", a part 
from fusion when we find a cost-effective way to do it.
efficient should have been... cost-effective
Kaj
25-Apr-2011
[6045]
First you'll have to find a way to do fusion in the first place - 
apart from bombs
Gabriele
26-Apr-2011
[6046]
Max, cost can only be a concern if you have enough of the energy. 
If not, then no matter how cost effective it can be, you also need 
to add other sources...
Cyphre
26-Apr-2011
[6047x2]
Geomol, I tried to calculate prices(incl. all taxes, distirbution 
etc.) from last year payments of our house consumption, here are 
the numbers:

electricity          $0.314(EUR 0.216) per kWh
natural gas      $0.072(EUR 0.050) per kWh
drinking water $3.817(EUR 2.629) per 1000 litres
so it looks we are close to Maui regarding the electricity :-)
Geomol
26-Apr-2011
[6049]
Good info, thanks!
AdrianS
26-Apr-2011
[6050]
I'm curious how many here are following the Andrea Rossi LENR/cold 
fusion news.
Henrik
26-Apr-2011
[6051]
I'm following Polywell, although there has not been much news lately.
AdrianS
26-Apr-2011
[6052]
The biggest news, and most promising, seems to be around the Rossi 
process. It's amazing how something of this magnitude is not covered 
by popular press. Not surprising, because of the bad rap the field 
got at its start, but the lack of coverage says a lot about how the 
scientific establishment operates.