Umweltgeschichte Saar[EN] From the Saarbrücker #Bergmannsfreund 1914:
The first really usable solar power machine is in operation in Egypt, near Cairo; it drives a pump system with a capacity of 27,000 liters of water per minute. This power machine has no firing system and therefore no chimney and does not require a heater; once in operation, it requires very little maintenance and can even remain in operation at night, i.e. without any interruption, if, as is the case with the system in Cairo, the storage of excess heat by means of boiling water is used according to a known method. In general, 250 horsepower can be generated by the machine from each acre of an area covered with mirrors in the manner described - in the sunny country of Egypt, to be sure. The production costs of the solar engine, its maintenance and operating costs are already in figures that prove its superiority over the coal engine, at least for tropical interior countries. Of course, solar power machines will only be installed in (...)
The first really usable solar power machine is in operation in Egypt, near Cairo; it drives a pump system with a capacity of 27,000 liters of water per minute. This power machine has no firing system and therefore no chimney and does not require a heater; once in operation, it requires very little maintenance and can even remain in operation at night, i.e. without any interruption, if, as is the case with the system in Cairo, the storage of excess heat by means of boiling water is used according to a known method. In general, 250 horsepower can be generated by the machine from each acre of an area covered with mirrors in the manner described - in the sunny country of Egypt, to be sure. The production costs of the solar engine, its maintenance and operating costs are already in figures that prove its superiority over the coal engine, at least for tropical interior countries. Of course, solar power machines will only be installed in (...)