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close this bookAppropriate Community Technology - A Training Manual (Peace Corps; 1982; 685 pages)
View the documentThe Farallones Institute Rural Center
View the documentCHP International, INC.
View the documentPreface
View the documentAcknowledgments
View the documentIntroduction
Open this folder and view contentsPhase I: Introduction to training
Open this folder and view contentsPhase II: Earthen construction and fuel-saving cookstoves
Open this folder and view contentsPhase III: Pedal/treadle power
close this folderPhase IV: Solar water heaters
View the documentPhase IV Calendar
View the documentSession 1. The role of the volunteer in development: international development part 2: the green revolution: successes and failures
View the documentSession 2. Introduction to solar water heaters
View the documentSession 3. Assessing community water needs and uses
View the documentSession 4. Introduction to solar water heating: determining hot water demand
View the documentSession 5. Plumbing a solar water heater
View the documentSession 6. Sizing a solar water heater
View the documentSession 7. Demonstrating a technical concept
View the documentSession 8. Shade mapping and solar siting
View the documentSession 9. Design of solar water heaters.
View the documentSession 10. Construction of solar water heaters
View the documentSession 11. Multi-media standard first aid
View the documentSession 12. Wind technology
View the documentSession 13. Volunteer in development part 2: women in development
View the documentSession 14. House design in four climates
View the documentSession 15. Presentation of solar water heaters
Open this folder and view contentsPhase V: Solar agricultural dryers
Open this folder and view contentsPhase VI: Concluding the program: The energy fair
Open this folder and view contentsAppendices
 

Session 2. Introduction to solar water heaters

Total time:

2 hours

Objectives:

* To review and discuss various types of solar water heaters
* To explain the basic principles of solar water heating
* To discuss examples of solar water heaters being used throughout the world, especially in developing countries

Resources:

* Zweig, Peter, "Introduction to Solar Water Heaters" Slide Show
* Attachment IV-2-A, "Sunlight and Glazings"
* Attachment IV-2-B, "Typical Thermosiphon Solar Water Heater"
* Attachment IV-2-C, "Lesotho Solar 'Hater Heaters"
* Attachment IV-2-D, "Early Solar Water Heaters"

Materials:

Newsprint and felt-tip pens, slide projector, screen

Procedures:

Step 1. (5 minutes)
Review session objectives and outline the activities.

Step 2. (45 minutes)
Distribute and briefly review the attachments (See Resources). Encourage a discussion of the application of solar water heaters in developing countries.

Trainer Notes

Begin the discussion by asking such questions as:

* Why solar? Or, why use solar energy?
* Why is solar energy considered a "second-rate" energy source in some countries?
* What factors have kept solar energy from being an "appropriate" technology?
* What factors have contributed to its "appropriateness''?

It is more useful to facilitate a discussion of each attachment than to describe each one to the participants. Encourage people to explain the sketches and drawings. If the explanation is incorrect or incomplete, ask for other interpretations as you guide the discussion and help the participants understand the material. Keep the discussion focused and do not spend too much time on any one attachment.

Take the time, however, to make sure that all participants understand the information, since it will be needed during the slide presentation and throughout the phase. Note that some systems shown are plumbed to sinks or showers while others must be filled and emptied daily.

Be sure that the discussion addresses such issues as -

* Plumbed and unplumbed solar water heaters
* Simple solar water heaters vs. large and/or expensive systems
* The needs and uses of hot water
* The participants' own use of hot water
* How that need may change once in the host country

Explain that there are some communities in the world where hot water is not found. No one has ever had hot water there and everything is ant always has been done with cold water.

Ask the participants:

* What important information should be obtained before attempting to introduce solar water heaters to a community?

* How could solar water heaters be effectively introduced to a community that has traditionally used only cold water?

Step 3. (60 minutes)
Present the slide show on solar water heaters, encouraging discussion and questions.

Trainer Notes

Again, as with the session attachments, ask the participants to describe each slide as it is projected Do not spend too much time on any one slide. Refer to the attachments as necessary. Focus the discussion on the possible utility of the different models in developing countries, how the devices function, what they are made of, their cost, etc.

Step 4. (10 minutes)
Conclude the session by asking the participants to identify what they feel are important points to keep in mind when considering the application of solar water heaters in the countries in which they will be serving.

SUNLIGHT AND GLAZINGS


Figure 1

Glazing Material

Short Wave-Length Transmissivity

Long Wave-Length Transmissivity

Polyethylene

85-95%

85

Polyvinyl

85-95 %

75%

Fiberglass

72-93%

10%

Glass

88-93%

3%


Radiation Wavelength (Micrometers)


TYPICAL THERMOSIPHON SOLAR WATER HEATERS

LESOTHO SOLAR WATER HEATERS


Figure 1


Figure 2

EARLY SOLAR WATER HEATERS


Climax solar water hrater

Advertisement for the Climax solar water hrater, 1892. The price of this, Kemp's smalles; unit, had just dropped from 525 to 515.

Below: Two ways to instrall the Climax, from a company brochure. pressunzed system (left), and praviryfed system (right).


Climax solar water hrater bracket on the wall

A. - Is the cock to use when the hot water is wanted. This is passes cold water into the heater, displacing the hot water and forcing it trough a pipe to the bath tub.
B. - Is the drain cock wich is used to prevent freezing.
C. - The air opening wich prevents vacuum in the heater and siphonic action.

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