Total time:

1 hour

Objectives:

* To discuss how charcoal is produced
* To identify and discuss advantages and disadvantages of charcoal as a fuel
* To discuss ways in which traditional charcoal cookstoves could be improved

Resource:

Aprovecho Institute, Helping People in Poor Countries, pp. 132-137

Materials:

Wood for fuel, retort (see Trainer Note, Step 4), examples of traditional charcoal cookstoves, newsprint and felt-tip pens or chalkboard/chalk

Trainer Notes

This session will require preparation of a charcoal retort. You will also need to have an operating charcoal stove for demonstration purposes (see Trainer Notes, Step 2).

Trainer Notes

Ask the participants if they have ever cooked on a charcoal fire and if they noticed how it burned differently from a wood fire. List their responses on newsprint, and encourage questions and discussions.

If they are not identified by the group, add the following characteristics to the list:

* Little flame
* More even heat
* Mostly radiant heat (pots need to be closer)
* Few hot gases (not suitable for stoves with tunnels)
* Needs more evenly distributed air (burns best on 25% - 35% grate)

For demonstration purposes, it is best to have a functioning charcoal stove on hand during the discussion.

Trainer Notes

Describe the earthen mound system, external fire charcoal retorts and internal fire charcoal kilns. Discuss efficiencies of each type (wood in - charcoal out) and the energy content of charcoal and wood.

Trainer Notes

To make a simple retort:

* Using a 60cm (2') section of stove pipe, load it tightly with wood, being careful to allow some air space.
* Cap the ends of the stove with ferromud (fine mesh wire plastered with a clay/sand mixture).
* Set the retort over an open fire.
* Periodically check the ends for air leaks. Leave the retort on the fire for several hours (see drawing below).

Figure

Trainer Notes

List the advantages and disadvantages in separate columns on newsprint. Add the following points to the list, if they are not identified by the participants:

Advantages

Disadvantages

* Low smoke

* Increased deforestation due to poor conversion rate (out of total wood burned for charcoal, there is a 65 80X energy loss)

* Light weight for transport

* Gives off poisonous fumes

* Less volume (easy to store, especially in cities)

* Dirty

* Used with low cost and portable stoves

* Carbon dust is health hazard

* Easy to see

* Stores well for a long period at a constant moisture content

* Provides employment

Explain that although charcoal causes more rapid deforestation, the demand for charcoal will continue. There will continue to be a demand for it as a fuel source in the cities. The need exists to develop more efficient charcoal production techniques and charcoal stoves.

Trainer Notes

Suggest the following improvements:

* Insulate around the stove and under the grate area (leaving sufficient draft).
* Install a damper.
* Construct a ferromud chimney around the pot.
* Recess the pot deeper into the stove.

Trainer Notes

Explain that everyone will have the option of building a charcoal cookstove in the second stove construction session, Phase II: Session 21.

Encourage participants going to urban areas or countries in which charcoal is common to build charcoal stoves in Session 21.