Appropriate Technology Dept. Sunseed activities September 2013

This month we completed the pending projects.

The biomass cookstove base structure has been reinforced and has been transported to the main house where it will be used. We started to cook usually, demonstrating that whatever can use it, has a very simple operation and is very efficient. We’re burning cane and almond shells. In short will be prepared other fuels. 2 hours of heat, are easily obtained. The gasification is very good, and does not generate smoke, so can be used perfectly to the side of the house.

We also have built a structure to support the solar oven with turning wheels that allow to point towards the sun. The box has been coated with fiberglass to protect it from the elements and painted white, to reject the sun’s heat on the outside. At noon you reach 144 degrees celsius, allowing to cook many dishes perfectly.

To finish the biomass stove, Lucia has spent many hours in the workshop. We reinforced the support structure, soldering metal tubes which connect the legs at mid-height. The last touch was to paint the part to be heated with thermal paint, and legs with outdoor paint.

We made several tests to cook. Remember that the system allows you to cook with a pan while we put the excess of heat into the oven, getting getting easily a temperature of 200 degrees, and can be used for another preparation. We baked cakes, lasagna, pizza and various vegetables with great success.

7-8 cm long cane chunks were used as a fuel, also almond hulls and wood scraps. Flame time depends on the amount and type of fuel with which filled the gasifier, in this case, the Kañon!!!. with half load of almond shells (about 4kg.) last for about 2 hours. With a whole load of cane (about 4 kg.), the flame time is about 40 minutes. A mixture of both, gives 1 hour combustion. With pieces of scrap wood, you get very good times too. In the gasifier flame concentrator, the temperature is about 1000 degrees Celsius.

As residential kitchen allows boiling the biggest pots available in Sunseed (for 40 portions of food) without any problem and quickly. The system must be improved to reduce the heat input into the pot, it can be excessive for dishes that require slow cooking.

For those applications where you need a long cooking time and using the gas stove is less sustainable and very expensive, this device reveals essential. Canning, making jams, syrups, cooking vegetables, etc., are carried out with completely renewable fuel, free and local.

I want to remember and dedicate the project to the volunteer who initiated, Alexis, that permeated the cookstove of good energy and enthusiasm.Thank you!

El horno solar ha sido también finalizado, instalado en el techo solar de la casa principal y puesto en marcha. Al equipo compuesto por Magued y Simón, se unieron María, Julia, Mukund y Lucía, con lo que la parte final del proyecto estuvo cargado de buena energía y mejores ideas.

After placing the double glazing at the sunshine entrance to create a thermal break to prevent heat from escaping trough the top, we proceeded to coat glass fiber outside the furnace to make it weatherproof and give long durability. We used a chemical that could be described as unsustainable and aggressive. To decide this, we considered the following factors:

  • By doing weatherproof (heat, cold, rain …), its duration will be longer than the existing solar ovens, whose wood is degraded rapidly over the months.
  • Fiberglass is a further insulating layer. In this case protects the outside of the wooden sandwich from hot sun. Being white painted increases this effect by reflecting more sunlight.
  • The cost is much lower compared to change the wood when degrade.
  • Has a structural reinforcement effect that makes it virtually unbreakable.

To facilitate the change in orientation of the oven to follow the sun, we made a metal structure with wheels at the end of the legs.

As it dimensions are really big, 90x90x45 cm., has a large capacity that allows up to 4 medium size pots to be placed. It also has 20 refractory bricks under the black sheet metal. In this way has a certain thermal inertia giving a preheating effect in the morning and increases the time of use in the evening.

Temperature measurements in production, have reached 144 degrees Celsius, more than enough to cook safely on sunny days. To test baking, various metallic round cookies boxes were painted black, creating several mini-ovens which baked cakes, bread and pizza. This is a good field to experience in the future. I get the impression, given the results, that the bread can be perfectly done in this solar oven, thus saving energy and money with regard to the use of propane furnace.

Congratulations to Magued for his tenacity in the project and to Simon for their invaluable support, ideas and fellowship. Thanks also to Mary, Mukund, Julia and Lucy for their help and enthusiasm in the project.

These two projects have earned a special video each.

Biomass cookstove at Sunseed
Solar Oven

Also are available the photo albums of both projects:

Sunseed AT Gas-Bio Septiembre 2013


Sunseed AT Solar cooker


Sunseed AT Septiembre 2013


Sunseed Septiembre 2013


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