Due to the high direct insolation in the Altiplano and the lack of firewood, concentrating systems have a high acceptance for solar cooking in this region. A study, which was car­ried out in 1998 has shown, that the firewood consumption could be reduced by 70 percent by solar family cookers of the SK14 type. A production of these solar cookers created new jobs in the local cooperative Pirca. Besides solar family cookers also community cookers are interesting. In order to improve the acceptance of cooking with solar power, it is nec­essary to set up a permanent installation of the cooker within a building. This can be achieved using a concentrating reflector, which has a fixed focus. In this project, a Schef — fler reflector was used. This kind of mirror is a section of a much bigger parabolic shape. With a reflector area of 8.8 m2, the aperture measures 5.5 m2. The reflector is fixed on a polar axis. This makes daily tracking with the sun easy, since only a uniform rotation
throughout the day is required. The seasonal adjustments to the sun’s position are ob­tained by adapting the angle and at the same time changing the shape of the reflector. The different shape is achieved by bending. So, at different angles of incidence the focus can be kept at the same place by shortening or lengthening the focal distance. The uniform rotation of the mirror is done by a electromechanical tracking system which works with two little PV-cells as sensors. Many hundred Scheffler reflectors have already been installed in many different countries (see http://www. dfg-vk. de/SolareBruecke/). The Workshop which was established as part of the BMZ project now makes a local production in Argentina possible. Within one year, 7 units have already been produced, including two solar bakery ovens. Due to the great power of the systems the acceptance in the population was found to be very high.

Technical data:

Surface of the Aperture (depending on the season): 4.5 — 6 m2

Maximum temperature: 1000°C

Optical efficiency level (aluminium/glass mirror): 75% / 65%

Maximum performance (ldir= 800 W/ m2): 3 kW

Size of cooking pot: 30 -80 l

Market price of reflector system in Argentina: 980 Euro