Ron, This is not a very good video clip, but it does show the entire 150 gasifier: http://youtu.be/8IcXDAK37gA This is a rough prototype made by hand. The mass-produced product should look better.
Also I do not envision that this gasifier be operated as a stand-alone device. For safety reasons it should be set within a counter-top enclosure, as seen here: http://dl.dropbox.com/u/22013094/150%20Gasifier/Jpegs/008.jpg Thanks. Paul On Sun, Mar 11, 2012 at 2:48 AM, Paul Olivier <[email protected]>wrote: > Ron, > > I did yesterday an experiment with aluminum foil to reflect back up the > thermal radiation emitted from the dome. > The aluminum starts to wrinkle and crack well before the burn is complete. > > Also I tried yesterday a wire mesh of an aperture of 30 mesh. > This did not work as well as what I am using now (a stainer that I bought > in the market). > I have yet to find the factory that makes this strainer, > and I do not have the instrument that is needed to measure its aperture. > > Ron, I think that the foam that you have found offers the most promise. > I am sure that this foam will deliver more radiant energy than stainless > steel wire mesh. > Also I hope to employ a type of funnel that would surround the dome and > focus the laterally emitted thermal radiation toward the pot. > Finally the pot has to absorb and not reflect. > > Thanks. > Paul > > > > On Sun, Mar 11, 2012 at 1:58 AM, <[email protected]> wrote: > >> Andrew, Paul, Crispin, list: >> >> 1. The last several paragraphs below are coming out more negatively >> on radiant heat capture than I think are appropriate. Remember, the >> initial information provided by Paul Olivier on March 2, when he said: >> >> "When a wire mesh dome is placed on top of the burner and burner housing, >> this roughly doubles the amount of heat being transferred to a pot:" >> >> 2. I think this doubling has little to do with the exchange below >> (and a few earlier that are similar). Radiant heaters are widely sold >> because of their efficiency in heat transfer - in many cases involving zero >> convection. Given we have only one (above) piece of data for one stove, >> the chances are that a doubling is not the maximum we can achieve. >> >> 3. I would look at this as a conservation of energy problem. We know >> that we can transfer more energy to the pot if the radiator is hotter. >> There may be catalysts that we can employ. We know how to use reflectors >> and obtain high absorption (and sometimes simultaneously low emissivity) >> In my reading on ceramic foam, I found that some foam is being >> employed so as to have gas combustion take place inside the foam!. >> >> 4. I hope that others can perform some experiments along these lines. >> >> Ron >> >> ------------------------------ >> *From: *[email protected] >> *To: *"Discussion of biomass cooking stoves" < >> [email protected]> >> *Sent: *Saturday, March 10, 2012 3:31:17 AM >> >> *Subject: *Re: [Stoves] radiant heat capture, total heat measurement >> >> On Fri, 9 Mar 2012 12:25:49 +0200, Crispin Pemberton-Pigott wrote: >> >> >>...and passes visible light and higher frequency infra red from hot >> bodies, >> >like the sun, >> > >> > >> > >> >Most of it, the rest makes it warmer (absorbs). >> >> Yes that which it absorbs make it warmer but equally as a warm body at >> equilibrium it will be re emitting longer wavelength IR. >> > >> > >> > >> >>but absorbs the lower energy infra red from cooler bodies like earth and >> >our bodies. >> > >> > >> > >> >Yes, and because it is warm, and active in the IR, it also emits IR but >> with >> >a low emissivity. In other words if you know the emissivity, you can read >> >the temperature with an IR gun. >> >> it is emitting a different (lower) frequency from which it has >> absorbed. >> > >> > >> > >> >But more to the point I was saying that at a lower (non 90°) angle, it >> >starts to reflect radiation from the top of the surface. Look at glass >> at a >> >low angle and it looks like a mirror. >> >> Agreed >> > >> > >> > >> >The point is that when reflecting heat, if the incident angle is past a >> >critical value, it reflects pretty much all of it so the issues Kevin >> >mentioned about the mirroring on the back don’t come into play. >> >> This depends on the refractive index of the two materials, going from >> a lower to higher there is always some light transmission, the other >> way round and you have total reflection, this is how a light fibre >> works. >> > >> > >> > >> >Paul’s question was about reflecting the heat. So the principles are the >> >reflectivity, surface finish, incident angle and emissivity. While a >> stove >> >may be good at sending IR radiation towards the pot, pots are not all >> that >> >good at picking it up, actually. Stainless steel pots are quite >> reflective >> >and do better picking up heat by convection. >> >> The major salient point is that radiation from heating something by >> flame/flue gases is only ever going to extract a minor portion of the >> heat in the gas stream. Consider a black body in the gas flow, it can >> never be hotter than the gas flow downstream of it, as you make it >> hotter it radiates more heat but the rejected gas flow is also hotter, >> either way you still need to have the convection do most of the work. >> AJH >> >> _______________________________________________ >> 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/ > -- 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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