Appropriate community technology - A training manual: Phase II: Earthen construction and fuel-saving cookstoves: Session 7. Cookstove operation function and design principles

Appropriate community technology - A training manual

Phase II: Earthen construction and fuel-saving cookstoves

		Phase II Calendar
		Session 1. Environmental health and sanitation
		Session 2. Traditional methods of cooking: an introduction to cookstove technologies
		Session 3. Fuel-saying cookstoves: gathering information
		Session 4. Cookstove design and innovations
		Session 5. Thinking in pictures: introduction to design drawing
		Session 6. Introduction to independent study
		Session 7. Cookstove operation function and design principles
		Session 8. Understanding the cookstove design process and soil mixes
		Session 9. Insolation meter construction
		Session 10. Cookstove construction
		Session 11. Nature of volunteerism: expectations beyond training
		Session 12. Food issues
		Session 13. The role of the volunteer in development: definition of appropriate technology
		Session 14. Stove promotion and dissemination
		Session 15. Explaining completed cookstoves
		Session 16. Evaluating cookstove efficiency
		Session 17. Diagnosing and repairing malfunctioning cookstoves
		Session 18. Other responses to fuel scarcity
		Session 19. Charcoal production and stoves
		Session 20. Custom and food
		Session 21. Design and construction of the second stove part one: stove base
		Session 22. Alternative cookstoves: presentations
		Session 23. Basic nutrition
		Session 24. Cookstove operation
		Session 25. Cookstove development and innovation
		Session 26. Cookstove information and resources/ evaluation of cookstove training

Session 7. Cookstove operation function and design principles

Total time:

2 hours

Objective:

* To operate a fuel-saving sand/clay cookstove

* To discuss the principles of heat transfer and heat loss

* To discuss the design principles for energy saving cookstoves

Resources:

* Attachment II-7, "Questions for Stove Operation"

* Aprovecho Institute, Helping People in Poor Countries, pp. 77-84

* Evans and Boutette, Lorena Stoves, pp. 20-25

* Large format illustration of a twopot, two-damper, sand/clay cookstove

* Illustrations of heat transfer and heat transfer within a cookstove

Trainer Notes

These illustrations should be prepared before beginning the session.

Materials:

Fuel, matches, grain and beverage utensils, examples of fuel-saving sand/clay cookstove(s), newsprint ant felt-tip pens.

Trainer Notes

* For this session you will need to have operating examples of fuel-saving sand/clay cookstoves. A dampered singer or concrete stove could be built for this session, due to their quicker construction and drying time.

* After the session and during the remainder of the training, you should encourage the participants to use the cookstoves (as well as open fires) in preparing their daily meals.

Step 1. (5 minutes)

Present the session objectives and outline the activities.

Step 2. (5 minutes)

Describe and explain the basic functions of the fuel-saving sand/clay cookstove

Trainer Notes

Indicate and describe the function of the cookstove baffles, damper, tunnel (flue) ant chimney.

Step 3. (5 minutes)

Distribute Attachment II-7, "Questions for Stove Operation," and have the participants read it.

Step 4. (1 hour)

Ask the participants to form groups and:

1. Collect fuel and prepare a grain and beverage on their sand/clay cookstove

2. Select a group member to record the answers from the attachment questions and to note the group's discoveries regarding stove operation for later discussion.

Step 5. (15 minutes)

Reconvene the groups and ask them how it felt to operate the stoves without previous instruction. Facilitate a brief discussion.

Trainer Notes

An important point to raise during this discussion is that often stove programs (as well as development programs in general) introduce a new technology concentrating on construction, with little attention to training the users in operation and maintenance. In the case of cookstoves, people will be able to operate the stove only as they understand it. It is possible that they will not operate it as it was designed to function and, therefore, will not gain its full benefit. Likewise, If the stove is damaged, they may be unable to repair it. Mention that these Issues will be covered in more detail and that it is of utmost importance to remember to involve the stove users in all steps of the development process.

Step 6. (15 minutes)

Referring to the attachment questions as guidelines, discuss air flow within the stove, starting and maintaining a fire and the effect of the dampers.

Trainer Notes

Post the illustration of the two-pot cookstove and use it to indicate the sequence for starting and maintaining a fire.

Step 7. (20 minutes)

Discuss the three types of heat transfer

Trainer Notes

* Ask the participants to define radiation, conduction and convection.

* Encourage the participants to illustrate their definitions with examples gained from their experience with the cookstoves.

* Discuss ways in which radiation, conduction and convection work for and against cookstoves.

* Ask where radiant, conductive and convective heat losses occur in the stove.

* Ask for examples of possible ways to minimize heat loss in stoves.

* Post the illustrations on heat transfer and heat loss and use them for reference during the discussion.

* Refer to Helping People in Poor Countries (See Resources) for background information on heat loss and heat transfer.

Step 7. (5 minutes)

Ask the participants to read Lorena Stoves.

Step 8. (20 minutes)

Facilitate a discussion on stove design, listing the important points.

Trainer Notes

* Briefly review the twelve essential design guidelines found on Lorena Stoves.

* Mention the importance of understanding these design guidelines and the principles of heat transfer and loss before constructing a stove.

QUESTIONS FOR STOVE OPERATION

A. Draft Dampers, Flues, Chimneys

1. Does there appear to be too much draft or too little?

2. How does the front damper affect the fire and function of the stove?

3. How does the back damper affect the fire and function of the stove?

4. How do baffles affect the flow of gases?

5. How do tunnel dimensions and tunnel condition affect the flow of gases?

6. What about chimney height? Diameter?

B. Cooking

1. Was there too much or too little heat to do the cooking task?

2. How much heat was at each pothole? (Amount of time to come to boil; length of boil; could you fry on potholes #2 and #3?)