Josh, Could a hand-crank or foot treadle system be operated at a village level? It might be too expensive for a household. Do you know of companies that make them?
Paul Olivier On Thu, Aug 30, 2012 at 10:59 PM, Josh Kearns <[email protected]>wrote: > What about a mechanical hand-crank or foot-treadle system with a flywheel? > Get 'er goin and then every few min. a couple pumps on the crank to keep > the flywheel up to the desired speed. > > Josh > > > On Thu, Aug 30, 2012 at 9:42 AM, Phil Hughes <[email protected]> wrote: > >> Let me toss in a few more factoids. >> http://www.batteryspace.com/li-ioncylindricalcellseries.aspx will give >> you a decent sample of the common LiION cells. The most common size in >> laptop batteries is the 18650 which is typically from 2.2 to 2.78Ah. When >> you see a laptop with a higher capacity battery it is typically cells in >> series-parallel. For example, a 6-cell battery is generally two strings of >> three 18650 cells in parallel. >> >> The explosing fist is real. The good news is that there are very >> inexpensive chips designed to charge these cells. You will find one (for a >> single cell) in all cellular phones. They will deal with maximum voltage >> and maximum charge current. They are also low drop-out as a typical use is >> to output 4.2V from a USB (5V) supply. >> >> In a typical laptop, you find other chips (generally more than just a >> single component) to charge the "almost 12V" string of LiIon cells from the >> typical 16 to 20V AC adapter. The disadvantage here is that you need to >> monitor the voltages of each cell in the string. Not complicated but that >> is what makes the 12V solution potentially more expensive than the 3.7V one. >> >> A 5V fan is an interesting possibility. First, if may operate fast enough >> from say 3.5V so a single LiIon cell would handle it. If not, a flyback >> converter to step up 3.7 to 5V would be cheap and high efficiency (because >> most of the power comes directly from the battery rather than needing to be >> "converted"). >> >> >> On Thu, Aug 30, 2012 at 9:36 AM, Frans Peeters >> <[email protected]>wrote: >> >>> Phil, >>> >>> 3x LiION =3,7Vx3=11,1V Charger needs 4,2x3=12,6 maximum or EXPLOSION >>> RISK >>> 2W motor at 12V-------->0,1666 A >>> 8h xO,166A =1,8Ah >>> Laptop cells are 3,6 Ah and more >>> Sun cell 15,6V---------> 12,6 V +3V for charging regulator LM317 >>> >>> PC uP fans exist at 5V x0,2A=1W you could power with 2 cells; >>> Also a dual fan of 2x 1W >>> >>> Regards >>> Frans >>> >>> I see Paul Oliver's work to be excellent and appreciate how a variable >>> speed >>> fan can offer excellent control over TLUD operation. My reservation is >>> that >>> there are many places where even the small power requirement (Paul says >>> 1-2 >>> watts) just isn't available. Lots of people here in Nicaragua are totally >>> off-grid and don't have reasonable access to a way to charge a battery. >>> So, >>> I am been thinking about options. Being, among other things, an >>> electronics >>> geek, here is what I have been thinking about. >>> >>> >>> Running the TLUD 8 hours a day at "average" fan speed means 12 watts per >>> day. At 12 volts that's one ampere hour. I have been thinking about a >>> couple >>> of approaches. One is "higher tech" but may be a better solution at an >>> equivalent or lower cost. In both cases I am just thinking of a >>> photovoltaic >>> panel to charge the battery. The difference is the battery voltage. >>> >>> Small PV panels are pretty common on the surplus market. For example, >>> Electronic Gold Mine (http://www.goldmine-elec.com/) offers an >>> assortment. >>> The specifications vary from 7 to 35 volts open circuit with output >>> power in >>> the range of 1-3 watts. Prices are from $4.50 to $15. As this is quantity >>> one retail price information, it is likely the could be found at >>> significantly lower costs. >>> >>> >>> As any PV-based system will need some sort of charge controller for the >>> battery and what PV cells (in particular, what voltage) will be >>> available at >>> the best price point, I am thinking that using a single-cell Lithium Ion >>> battery (3.7 volts nominal) would make the most sense. Units with a >>> capacity >>> of 2.2 ampere hours and more are commonly used in laptop computers. They >>> offer reasonable life, low cost and the possibility of finding them on >>> the >>> surplus market. The cells can be paralleled if higher capacity is needed. >>> >>> A switching "up-converter" would be needed to supply the 12 volts needed >>> for >>> the fan. The speed control could be incorporated into the up converter >>> which >>> would reduce the cost and increase the efficiency. >>> >>> The alternative would be to use a more or less 12 volt battery (three >>> Li-Ion >>> cells in series) so that the up-converter could be eliminated. My initial >>> guess is that the reduced electronics cost would not be as much as the >>> increased battery cost but it is a viable alternative as long as higher >>> voltage surplus PV panels are available. >>> >>> While this sounds like a lot of electronics, this is all very common >>> stuff >>> that you find in, for example, cellular phones. There is some design work >>> needed but the actual component costs will be very low. >>> >>> Comments? >>> >>> -- >>> Phil Hughes >>> [email protected] >>> >>> >>> >>> >>> >>> >>> >>> _______________________________________________ >>> Stoves mailing list >>> >>> to Send a Message to the list, use the email address >>> [email protected] >>> >>> to UNSUBSCRIBE or Change your List Settings use the web page >>> >>> http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org >>> >>> for more Biomass Cooking Stoves, News and Information see our web site: >>> http://www.bioenergylists.org/ >>> >>> >> >> >> -- >> Phil Hughes >> [email protected] >> >> >> >> >> >> _______________________________________________ >> Stoves mailing list >> >> to Send a Message to the list, use the email address >> [email protected] >> >> to UNSUBSCRIBE or Change your List Settings use the web page >> >> http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org >> >> for more Biomass Cooking Stoves, News and Information see our web site: >> http://www.bioenergylists.org/ >> >> >> > > > -- > Josh Kearns > PhD Candidate > Environmental Engineering > Engineering for Developing Communities > University of Colorado-Boulder > > Director of Science > Aqueous Solutions > www.aqsolutions.org > > Mobile: 720 989 3959 > Skype: joshkearns > > > > > > _______________________________________________ > Stoves mailing list > > to Send a Message to the list, use the email address > [email protected] > > to UNSUBSCRIBE or Change your List Settings use the web page > > http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org > > for more Biomass Cooking Stoves, News and Information see our web site: > http://www.bioenergylists.org/ > > > -- Paul A. Olivier PhD 27C Pham Hong Thai Street Dalat Vietnam Louisiana telephone: 1-337-447-4124 (rings Vietnam) Mobile: 090-694-1573 (in Vietnam) Skype address: Xpolivier http://www.esrla.com/
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