As plans for a 20x36 off grid cabin shape up, I'm still at a loss about whether to go solar, microhydro or a combo. Seems there are very few options for someone with a creek of my variety. The banks are 4ft to 20ft high so pulling water out of the river to a pumphouse is a no go. I've got almost no measurable head over my 2000ft of frontage making Pelton's and most other turbines useless. Average flow rate is 3ft/sec (2MPH), average depth of at least 10inches, and width of 90ft with plenty of riffles. That's a cross section of 75sq/ft, and flow of 13,500 GPM, not a small creek by any means.
In a crude experiment this weekend, I dropped a bag with a 10inch diameter into the current, let it pull a string attached to a fish scale. This was meant to approximate the drag of a bicycle wheel with several attached cups in the water at any given moment. It measured 4-5lbs pull without any damming or focusing of water. A typical bike wheel of 24 inches with attached cups should then experience a 5ft/lb torque. Circumference of 6ft means a maximal rotation of 30RPM. I have no experience in mech engineering so I have no clue if 5ft/lbs can be turned into any useful torque at 800-1000RPM.
My motor pulled from an old scooter produced 24V at 1000RPM with almost no torque. On a 12V load rated 130W it was able to produce 20W with a significant increase in torque resistance. Any thoughts?
All I can say is I wish I had a stream. Any stream. Also I'm over my head when it comes to hydro power. ::)
Quote from: MountainDon on October 19, 2010, 12:06:11 PM
All I can say is I wish I had a stream. Any stream. Also I'm over my head when it comes to hydro power. ::)
Sounds like me and solar, Don!
Glad I just found 2 important calculations I'll post in case someone in the future googles something similar.
746 Watts = 1 HP
Torque in ft/lbs is calculated by: Rated motor HP/RPM, then multiply product by constant of 5250.
So a 1/10HP DC motor rated at 1000RPM would have a torque of .5ft/lbs at 1ft from the shaft.
http://www.unitconversion.org/unit_converter/energy.html (http://www.unitconversion.org/unit_converter/energy.html)
http://www.unitconversion.org/unit_converter/power.html (http://www.unitconversion.org/unit_converter/power.html)
http://www.otherpower.com/otherpower_hydro.html (http://www.otherpower.com/otherpower_hydro.html)
Awesome, Don, thanks!
Now to see if my treadmill has a DC/PM motor! Lord knows I'm not burning any calories on it in a long time. Maybe it's time it made some energy for me instead!
Doc
Hydro systems always interest me. I was on vacation "out West" this year and saw a municipal system that was fed by water that fell less than six feet. (Was it Rapid City? ... I think so.) The point being, if you've got enough flow ... it can be effective at a very short fall.
Canyon Hydro use to specialize in very small systems ... they have grown over the years, but still have micro-hydro info on their website:
http://www.canyonhydro.com/products/products.html
looks like a very good link to design info on the canyon site
http://www.canyonhydro.com/guide/index.html (http://www.canyonhydro.com/guide/index.html)
I started researching microhydro and found a few good resources. First, microhydro.net (http://microhydro.net) has a wealth of information and links. From that site, I found a Yahoo Groups forum, at http://groups.yahoo.com/group/microhydro/ (http://groups.yahoo.com/group/microhydro/) .
A free book in pdf format, Micro-Hydropower Systems: A Buyer's Guide, prepared by Natural Resources Cananda, available here:
http://canmetenergy-canmetenergie.nrcan-rncan.gc.ca/fichier/79276/buyersguidehydroeng.pdf (http://canmetenergy-canmetenergie.nrcan-rncan.gc.ca/fichier/79276/buyersguidehydroeng.pdf)
A US Dept of Energy site in Microhydro: http://www.energysavers.gov/your_home/electricity/index.cfm/mytopic=11050 (http://www.energysavers.gov/your_home/electricity/index.cfm/mytopic=11050)
Finally, a Euro Commission guide to small hydro: http://www.microhydropower.net/download/layman2.pdf (http://www.microhydropower.net/download/layman2.pdf)
One of the decisions you have to make deciding on solar or hydo is maintenance. It is the biggee! If you have a good solar location and latitude, it will be hard to beat if you do not like going outside at night when the creek is rising...
That said, I wish I could do both!