-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at
formatting link
| 1962 | I love to cook with wine. Sometimes I even put it in the food.
I doubt that turbines or solar panels or solar plants will actually work for the lifetimes that are used to calculate return. I sure wouldn't want a mess of solar panels, with their associated wiring/controls/inverters, on my houses.
--
John Larkin Highland Technology, Inc
picosecond timing laser drivers and controllers
jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com
There are older wind turbines on the hills near my house that have been there for at least 15 years. (With other, newer, bigger ones nearby.) I'm guessing that the repair and maintenance costs/ schedules for them is pretty well known.
The one meeting I went to, I heard that the energy cost pay back time for the wind mills is ~6 months, with total investment return in 3 years. I think this was for the big ones. (Google Sheldon Wind Farm for pictures.)
Provided it is installed somewhere with a mean windspeed above 6m/s then there is every chance that the wind turbine will achieve a very handsome lifetime payback of the energy invested in building it.
The same cannot be said of photovoltaic arrays which have a lifetime payback even on very optimistic assumptions of at most 7x.
McKays book "Sustainable energy without the hot air" is a reasonable assessment of the science and engineering reality from a UK perspective.
Problems arise when the kit is installed to farm the grants and various renewable subsidies that governments offer as inducements. Particularly dodgy is paying them by installed capacity rather than power delivered.
Wind turbines - like every other work of man - are fallible. For one reason or other the high-wind protection mechanisms occasionally fail, and the wind turbine falls down, with photogenic results.
Conventional electricity generating systems have their own problems, but they mostly take place behind closed doors, out of reach of photographers.
Hydroelectric dams are the obvious exception - the one that failed in China killed 170,000 people, and even the Chinese government couldn't keep that under wraps.
Hi John, I was going to respond, but I was thinking how great SED has been lately mostly electronics, or instruments.
So I'll ask the instrument type question instead.
Too much insulation? I've got this Rb cell heater I made years ago. The cell is a 1 cubic inch cylinder. (diam. = length = 25mm) It's inside a 4" diameter plexiglas cylinder. There's a 1" diam. optical path through the middle. with windows one the ends, And about 1/2 inch of insulation. There's a ~50 ohm heater of bifilar wound wire on a glass cylinder.
It works fine, but it's got an awful time constant. (I'll have to measure the voltage at max. temperature.)
I was thinking maybe some holes in the insulation, more heater power, but faster.
Is the heater wound directly on the glass cylinder? What's the desired temperature?
Faster heating needs more power, which implies a temperature sensor to limit the max temp. A wire won't transfer heat very well to a glass cylinder, and one way to cut glass is with a hot wire.
I'd consider using a Kapton heater/sensor thing wrapped around the cylinder, which would be less glass-cuttery than just wires. If you're talking roughly 110C, a Kapton+adhesive thing would work, with maybe something else, like a couple of tie-wraps or o-rings, to keep it from unwinding over time. Lots of people will make you Kapton flex heaters. Take a look at Minco, then buy something cheaper.
You might be able to use just a long skinny copper trace as both the heater and the sensor. Maybe a long narrow Kapton strip with a field-canceling copper trace or so, wrapped around the cylinder.
--
John Larkin Highland Technology, Inc
picosecond timing precision measurement
jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com
Yeah the heater wire is wound on the outside of the glass cylinder. (Wire concentrated at each end.) But then the inside of the cylinder is exposed to the open space between the window(s) and the cell. So it's far from optimum. (The experiment totally hates anything magnetic. and there are some exterior RF coils so metal is not great either.)
Temperature is 25 C to ~120 C or so.
50 C is optimal as far as the signal strength.
Oh sure there's a sensor too. A copper /constantin TC. The constantin is magnetic, but it's a thin piece.
Yeah we make our own bifilar heaters with kapton tape to hold 'em in place.
Good stuff kapton tape.
Thanks for the nice reply. (I hate all the political crap. Why is everything so divided? I like both wind mills and hydro-fracking.
Windmills sure look fragile to me. The blade/generator assembly explodes or catches file, or the gears strip, or the pylon breaks near the ground, or an insufficient concrete base tips over.
There are a lot of pics and vids online, but I can't estimate what fraction of wind turbines fail.
formatting link
--
John Larkin Highland Technology, Inc
picosecond timing laser drivers and controllers
jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com
How is the time constant "awful"? If you get a single pole response to a ch ange in heat input, you are generally better off if the time constant is lo ng - external changes are kept well away from the area you are controlling.
If you've got a two pole response - which usually means that your temperatu re sensor is appreciably separated from your heating element, life get more complicated. If you are using a PID algorithm to control the temperature, the proportional gain then has to be kept pretty low to prevent oscillation , and you rely on the integral term to get decent regulation.
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.