[Stoves] TEGs In-Reply-To=%3C9pc0kb1vrd6p4omok6ncg7iqig2cgfrf3j%404ax.com%3E

[Ronal W. Larson]

Paul and List, cc Andrew

	1.  I can’t find the message from Andrew Heggie that you were responding to, so hope Andrew can identify how to find it.  Regardless, you have given a strong justification for not worrying about the thermal draw of a TEG.  

	2.  Following the TEG theme though a little - could one save on costs considerably if you have a simple TEG that has no battery or grid connection?   One would only have power proportional to the stove thermal capabilities. You would probably still need a control circuit that lowered fan speed, if needed to get the right stove power level.

	3.  My main reason for responding though is that you may be the one and only stove person who has been able to do highly technical stove development - because of the strength of Philips, as a huge and admired multinational.  I have never seen your original stove up close.  Also only seen the current version from afar - that being (I think) now manufactured in Africa.  But I have always read/heard that you (for Philips) had designed the cleanest and most efficient stove.  Thank you for all that excellent work.

	4.  So I have these questions, assuming that you and Philips are out of the stove business (but hoping you/Philips still could re-enter, which would probably preclude your answering any of the following):

	a.  I remember your reporting that you personally regularly cooked so as to save the char, although that was not (I recall) advertised by Philips (rather char was to be consumed, with changes made in primary air flow to keep the power level as desired).  
	 Was there ever any Philips study on the virtue of only producing char?  (For either resale or biochar use?)  

	b.   What are your personal views of doing that (to produce a lower cost version, with income generating potential)?

	c.   Were there ever any computer simulations by Philips of the air flow and combustion details (that can be shared)?  

	d.  Any published papers, or even company documents that could help others?

	e.   Can you now tell us of any design options that you wish could have been further used in a lower cost Philips stove for easier sale in developing countries?

Again - really good to see your response to Andrew.  I hope all is going well for you.

Ron


> On Jun 1, 2016, at 6:47 AM, Sluis, Paul van der <paul.van.der.sluis at philips.com> wrote:
> 
> Dear AJH,
>  
> The Philips stove does NOT use significantly more fuel because of the attachment of the TEG.
> The TEG unit takes around 100 W of heat from the fire. 98W is waste heat of the unit (2% efficiency). That 98 W is recirculated into the fire because it is used to preheat the combustion air.
> The remaining 2W is fed to the fan. In the fan 1.8W is transformed into heat (just 10% efficient). Also this 1.8W is fed back to the fire.
> So just 0.2W is actually taken from the fire. An estimated 80 % of that power is lost as pressure drop over the nozzles that feed the fire with high velocity air. That loss is gain transformed into heat that comes into the fire.
> So the real power taken is around 0.04W. That needs to be compared to the power produced: 4000W. So an estimated 1/100000th extra fuel might be required.
> The might comes from the fact that in this case the energy lost is caused by the kinetic energy of the air moving away from the fire. But even a natural draft stove has these losses.
>  
> So it is safe to assume that with the Philips construction NO additional wood is required because of the use of a TEG.
>  
> Kind regards,
>  
> Paul.
> P Take care of the environment, print only if necessary ...
>  
> 
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