Posts Tagged Solar Cooking
This page has been compiled to address the Solar Cooking Storage issue with simple, inexpensive and effective methods of heat storage. It is based on some very old methods using stones and large sealed chambers that are outlined in The Ancient Solar Premise
The first method just has a black sheet of metal wrapped tightly around a solid fired house brick; this is aligned with three others and placed in an insulating box. See diagram. The energy throughput can be increased by increasing the number of metal casings and reducing the size of the bricks. This is a slight improvement on just placing black stones in the base of a box cooker.
Storage with High Energy Throughput
The second arrangement increases the throughput of energy, both in and out, by increasing the metal contact area. The same metal sheaf is used as above, but there are pipes welded to the interior. The pipes fit tightly into the holes in hollow fired house bricks. The pipes are cut along one edge to allow for expansion without cracking the bricks.
Both arrays are used in the same way. Prior to cooking the brick arrays are left in the base of the solar cooker. As the sun heats the metal surface, the energy is transferred to the bricks. This allows the bricks to heat up and store the sun’s energy. If the array is exposed to the air, an insulating lid needs to be put on the metal surface when the sun disappears. This is also beneficial within enclosed box style cookers as an extra insulation measure.
Cooking can be carried out in the normal fashion by placing a pot or tray of food onto the surface whilst exposed to the sun. The heat within the stones allows the cooking to continue even if the sun is obscured.
Alternatively, cooking can be carried out purely with the heat stored in the bricks. At sunset, the food is placed in the box cooker and the lid is closed. This allows the food to slow cook with the heat from the bricks.
With this second approach, there is a clear relation between the amount of food that can be cooked and the mass of the bricks. The bricks should weigh more than the food and be heated to as high a temperature as possible. This is achieved with large reflector panels.
In both cases, the speed of cooking is improved because the heat is being directed at the base of the food. Convection currents take it upwards guaranteeing the whole is at temperature. The colors of the foods are also incidental in this approach since it is the stones and the metal conductor that deliver the heat.
Steel sheets were used in tests for the first arrangement and proved good enough conductors. Clearly copper would be a much better conductor of heat though significantly more expensive. Iron may be a good compromise.
Bricks were used in all of the tests. The principle is based on storing the sun’s energy in a variety of dark stones such as granite, basalt and obsidian. A variety of materials can be used in the arrangements. Natural stones are the most durable, store energy very well and do not even require the metal sheaf if they are black. However, because of the expense in some regions, fired house bricks prove a reasonable substitute. They can be used with paints, but the throughput is limited by the contact area. The designs above double or triple the surfaces through which the heat can be transferred.
There are composite bricks designed specifically for storing heat used in electric storage heaters. These may prove the best material for the task.
There are several issues with this style of solar heat storage.
The primary one is that the stones have to be preheated before cooking occurs. This means there are initiation times proportionate to the mass of stone and the temperature required. However, this is also the source of the utility, since the cooking can continue at night or whilst there is no sun. This removes the primary temporal restriction on solar cooking,
The brick heat capacities vary greatly from place to place. This is because of the different clays used and the variety of firing temperatures. This is also true of the natural stones, which form with different compositions and conditions. Each region requires the stones to be tested in practice to realize assured guidelines.
The insulator used in tests was a standard polystyrene icebox with layers of aluminum foil and cardboard protection. This proved an excellent insulator. It retained the heat within the stones overnight. The problem was the degradation of the polystyrene over time because of the heat. This reduces both the storage capacity and the time it can be stored. The exact figures for this area are a constantly moving target.
The Secrets of the Sun Sects covers a large number of areas,
Here is a summary
THE SUN DEVICES OF ANTIQUITY
1. Burning Mirrors – an overview of what parabolic mirrors are able to do
2. Ancient Mirror Math – The simple math & geometric solution to Archimedes burning mirror problem
3. Dish Construction – How to make 10Mw/Sqm solar concentrators in antiquity or a garage
4. A New History of Mirrors – The implications for Greeks, Egyptians, Alchemy, Incans and more.
5. Star Wars – The use of burning mirrors on the ancient battlefields
The Sun Temples
6. The Sun Temples – A description of a solar chamber, energy and usage across the ancient world
7. Temple Mountains – The arrangement of sun chambers on step pyramids builds to ancient solar industries
8. Temple Distribution & Climate – The rationale for the solar chamber variances across the globe
9. Stone Circles – The solar premise applied to neolithic stone circles
10.Conclusion – The ancient world was powered by sunlight
THE SUN DEVICES
11. Solar Tools – A guide to making powerful sun dishes today
12. Food & Water – Using ancient techniques to fry, boil and cook at home or in the factory
13. Climate Control & Power – Using old technology to cool the home and produce power 24/7
14. Materials & Crop Processing – Solar Recycling, refining, materials synthesis & agricultural applications
15. Lost Techniques of the Solar Artist – Stone cutting, finishing, ceramics & gems
16. Miscellaneous Devices – How to make & use powerful Ancient Telescopes
17. Commercial Concerns – Benefits & reservations in the commercial environment
THE SUN SECTS
18. Revising the Past – Adding the Ancient Solar Sects to the record
19. The Inception of Civilization – Did civilization start with a hot black stone or fire?
20. European Sun Sects – The emergence of neolithic solar powered cultures
21. The Egyptian Sun Sects – The utility of sun gods & their temples/tools
22. Egyptian Priestly Orders – The skills hierarchy of the ancient solar orders
23. The Demise of the Sun Cults – The reasons for failure
Modern Solar Sects
24 The Transition Cultures – The switch from solar energy to sun worship
25. Eastern Religions – The Solar Cult legacies of the East
26. Western Religions – The Solar Cult legacies of the West
27. Miracles of Light – Biblical refs to solar devices
28. The Prophecies – 3 Ancient Prophecies reinterpreted
29. A Bright Future – Some very optimistic outlooks
A. Missing Greek Math – Tables of Hipparchus & Archimedes
B. The Power of Spherical Mirrors – The full math proof behind burning mirrors
C. Thermal Properties of the Sites – Detailed energy calculations for sun temples and stones
D. Projects – Completed and ongoing projects, High tech, low tech and historical