[Stoves] Powering a TLUD Fan

[Paul Anderson]

Phil,

Thank you for your excellent comments.   I am not an electronics guy, so 
I will trust in what you say until others might find issues to discuss.

How can we proceed?   You are in Nicaragua, right?

As soon as I have some few units from Paul O., we can do some trials.

Paul

Paul S. Anderson, PhD  aka "Dr TLUD"
Email:  psanders at ilstu.edu   Skype: paultlud  Phone: +1-309-452-7072
Website:  www.drtlud.com

On 8/30/2012 9:13 AM, Phil Hughes wrote:
> 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
> nicafyl at gmail.com <mailto:nicafyl at gmail.com>
>
>
>
>
>
>
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