Solar still for sea or salty water
|One of the problems afflicting a large part of humanity is the lack or shortage of water. There are places on the planet where the water beds are hard to reach, and the only water available is salt water. |
Nevertheless a simple still for producing small quantities of water can be built with little effort and cost. The resulting water is distilled, and therefore a small proportion of salty water has to be added to make it drinkable. At present, the construction of desalination plants for sea or salt water is still a costly and difficult enterprise, but for small quantities the still system is both simple and economical.
|Solar Dryer |
Utilised all over the world, the dessication of food products to preserve the surplus is in itself a very simple process. The traditional techniques, which were used by our grandparents, make direct use of the action of the sun, laying out the food to be dried on terraces or roofs.
In this way, however, the food is also exposed to dust and insects, to unexpected rainfall and to the humidity of the air, and sometimes the drying time is very long, so that the product laid out to dry may even deteriorate. The use of the solar dryer improves the quality of the dessication because the food is laid out in a closed and protected space, while the heat supplied enables it to dry out extremely rapidly.
The technology of photovoltaic panels is fairly sophisticated, but the structures are in themselves extremely simple. They were used for the first time in space technology on the satellites of the 50s, and are still in use today. At present they are used to produce electrical energy to power calculators, watches and other objects of everyday use, as well as on a larger scale for the irrigation of vast agricultural areas, and to supply the energetic requirements of a normal dwelling; their use is increasing in direct proportion to the improvement of the relevant technologies. The materials used for the construction of photovoltaic cells are produced from ultra-pure silicon obtained through complex and expensive processes; these are currently in continuous evolution, and it is to be hoped that this technology may create a major source of clean and renewable energy for the near future.