More on early history of TLUD stoves:
Ron Larson wrote:
From: Ronal W. Larson [mailto:firstname.lastname@example.org] Sent: Tuesday, February 21, 2017 10:46 AM
To: Discussion of biomass <email@example.com>; Tom Miles <firstname.lastname@example.org>
Cc: email@example.com; Paul Anderson <firstname.lastname@example.org> Subject: Re: [Stoves] : Early TLUD history… Re: Friz Handel’s Bush Buddy history
Re: [Stoves] : Early TLUD history… Re: Friz Handel’s Bush Buddy history
Tom, list and ccs
Can you clarify on your 1980’s testing of the (3?, all updraft?) Hottenroth stoves whether any produced char?
And Tom Miles replied:
Subject: RE: [Stoves] : Early TLUD history… Re: Friz Handel’s Bush Buddy history
Date: Tue, 21 Feb 2017 12:07:05 -0800
From: Tom Miles <email@example.com>
To: ‘Ronal W. Larson’ <firstname.lastname@example.org>, ‘Discussion of biomass’ <email@example.com>
CC: firstname.lastname@example.org, ‘Paul Anderson’ <email@example.com>
The simple answer is yes. We made charcoal in the Zmart Stove. It is very well described in the 1991 paper by Harry LaFontaine and Tom Reed. In it he states that “approximately 15% of the original wood mass is converted to charcoal which can be used for further cooking or to provide a sources of income for the poorer sections of the Third World.” They demonstrated the Hottenroth stove at the IGT Conference cited below.
Reed, T.B., 1991. ”An inverted downdraft wood-gas-stove and charcoal”, with LaFontaine, H., in Klass, D.L. (ed.), Energy from Biomass and Wastes, 15, 15th Annual Conference on Energy from Biomass and Wastes, Institute of Gas Technology, Washington, DC, 25-29 Mar, pp. 1023-1049.
I remember making very nice char while we conducted “water boiling” tests. : – ) We probably still have samples of the char.
We discussed gasification with Tom from about 1976 when he became interested in work that we had done on biomass densification and gasification. We designed equipment for preparing and feeding gasifiers of all kinds from then on for public and private clients. The late 1970s and early 1980s were active periods of gasifier testing and development. I remember Tom demonstrating his stratified downdraft gasifier at his lab. It was gold plated so that you could see the flaming pyrolysis in the fuel bed. He mentions stratified downdraft gasification in his 1991 paper. I was with Tom in South Africa, in April, 1985, presenting in a gasification session at a Forest Products meeting when he apparently had the idea of a [inverted] downdraft stove. During the next few years he worked with Hottenroth and Fontaine promoting stoves which incorporated gasification principles that evolved into what by 1991 he termed the inverted downdraft wood gas stove and charcoal producer.
“The stove is ignited from the top and burns down through a reservoir of wood, forming charcoal. No external power is needed, natural convection causing air to flow up through the wood, burning and gasifying most of the volatiles which then pass through the glowing charcoal, resulting in a relatively clean combustible gas. A secondary flow of preheated air is supplied to the combustible gases which result s in an intense, clean flame with a miniscule amount of soot and smoke.”
“VITA has made extensive tests of various stoves in Montserrat, West Indies, and has developed and started to mass produce stoves in Upper Volta. Aprovecho Institute is recommending factory mass-produced stoves in its drive for 100 million stoves in 20 years.”