Re: The Mayon Turbo Stove

[RSamson@reap-canada.com]

Thanks for the feedback on the stove from  Paul, Elk, and Ron.

We are now in the process of improving some of the terminology to describe the
different stove components on our web site so readers will find it easier to
follow. Please find below some further explanation which hopefully responds to
your initial questions.

There are two main components to the cooker.

1. The hopper (or outer fuel bin) which  gravity feeds the bulk loose fuels like
rice hull, sawdust and coffee hulls into the combustion area.

2. The centrepiece consists of the inner cone and centre drum which are welded
together at the base. No air space is left in between to prevent smoke coming up
between the two pieces (also rice hull should not be spilled in this area).
Small quantities of solid fuels are added directly from the top into the inner
cone.

When putting together the components, the centrepiece is descended into the
hopper until a 1 1/8" gap is left on all sides between the centrepiece and
hopper and it is fixed at this location. This spacing enables tapping to gravity
feed fuel from the hopper into the combustion area below the centrepiece. The
draft created by the fire in the inner cone draws air in through the hopper
which prevents fires occuring in the fuel storage area. The holes in the hopper
are directly under the centrepiece and provide the air flow to cause pyrolysis
in the fuelbed. The suggestion to change the entry of air from the bottom of the
centrepiece would provide air above the fuelbed.

Initially when we start the stove (or if it goes out) we have no draft. Opening
a space between the hopper and centrepiece with your hand or a utensil allows
air to pass freely into the inner cone. Once the draft is created the stove
itself will draw the air it requires. Opening the large hole accelerates the
stoves starting. We close the hole after starting to prevent an excess air
situation.

The low cost of the cooker is really a function of three things: a simple design
which is not material intensive, finding effective and affordable equipment to
streamline mass production, and training a dedicated group of people (in our
case mainly farmers sons) to build  stoves for our partner farmer organizations
(who are the stove sellers).

The stove will last less than one year if exposed to rain and it burns a lot of
solid fuels. It needs to be kept dry. We use 16 gauge steel for the centrepiece
and are looking at switching to 16 gauge steel for the hopper as well. The heat
intensity created really isn't that bad with rice hulls but it is with hotter
burning fuels like coconut shells. We anticipate replacing the centrepiece every
1.5-2 years and the entire unit every 3 to 4 years.

As far as maintenance, there is little tapping required to keep the stove
functioning or need for manual ash removal. Perhaps the biggest maintenance
issue now is to watch the stove for fuelbed fires when it is being used for
extended cooking periods (eg greater than 30 minutes). We need to keep adding
additional hull or to bury the rice hull material that is against the centre
piece if the stove gets quite hot and the rice hull is quite dry.

We have data on the efficiency of the Lo Trau cooker. We have not tested our
cooker yet but Dean Still has graciously offered to test it for emissions and
efficiencies. If anyone is currently assessing emissions of stoves for GHG or
household smoke related studies we would be most pleased to provide a stove for
your trials.

Ralph Overend from NREL was the Technical Monitor on our Subcontractor Report
for the "Strategies to Enhance Biomass Energy Utilization in the Philippines".
He provided very helpful discussions in creating the overall analysis and
provided effective input into improving the economics of stoves analysis.
REAP-Canada supported NREL on their  USAID project work in the Philippines
because we were one of the few organizations that had a history of working in
the bioenergy and agriculture fields and existing relationships working with
Philippines scientists and peasant support groups. The report can be found at:

www.nrel.gov/docs/fy02osti/30813.pdf.

An earlier CIDA project allowed us to intially field test the Lo-Trau stove in
Negros communities along with other appropriate technology equipment as part of
our Agroecological Village development programming. CIDA will feature the stove
as part of their presentation on the Canada Climate Change Development Fund at
Globe 2002 in Vancouver next month. We have several preliminary reports for CIDA
on the poverty alleviation impacts and the GHG mitigation potential of the stove
which we will post on our web site.

Thanks again for all your positive feedback. We look forward to work with you
through the Stoves discussion group to improve it further.

Trevor Helwig, Claudia Ho Lem and Roger Samson

Resource Efficient Agricultural Production-Canada
Box 125, Maison Glenaladale,
Ste Anne de Bellevue,
Quebec, CANADA
H9X 3V9
WWW.REAP-CANADA.COM
Tel. (514) 398-7743
Fax (514) 398-7972

"Creating ecological energy, fibre and food production systems"






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