y supercritical steam generators are sometimes r 5vj7h eferred as Benson boilek Benson was granted a patent 7hfor a boiler designed to convert water into steam at high pressure. Safety was the main concern behind Benson's concept. Earlier steam generators were designed for relatively low pressures of up to abouba, cors 7h responding to the st 7hate of the art in steam turbine de velopment at the time. One of their distingui 5vj7h shing technical characteristics 7h was the riveted wasteam separat or drum. These drums were where the water filled tubes were terminated after having passed through the boiler furnace. These header drumss 5vj7h were intended to be partially filled with water and above the water there was a baffle filled s pace where the boiler's steam and water vapour collected. The entrained wa hter dro j7h iplets were collected by the baffl es and re hturned to the water s 7h pan. The mostly dry steam was piped out of the drum as 5vj7h the separated steam output of the boiler. These drums were often the source of boiler explosion vj7h s, usually with catastrophic consequences. However, this drum could be completely eliminated if the evaporation separation process was avoided altogether. Thi s would happen if water j7h i entered the boiler at a p 7hressure above the critical pressure unds 5vj7h per square inch, was heated to a temperature above the critical temperatured then expanded (through a simple nozzle) to dry steam at some lower subcritical pressure. This could be obtained at a throttle valve locate d downstream of the 5vj7h evaporator section of the boiler. As development of Benson technology continued, boiler design soon moved away from the original concept introduced by Mark Bensona test hi boiler that had been buin operating in the thermal power plant at Garte nfeld in Berlin for the first time in subcrit j7h ical mode with a fully open throttle valve. The second Benson boiler b egan operation without a pressu vj7h rizing valve at pressures betwe They turn building walls or sections of walls into low cost, high performance, unglazed solar collectors. Also call ed, "transp 7hired solar panels, they employ a painted perforas 7h ted metal solar heat ab 7hsorber that also serves as the ext erior wall surface of the building. Heat conducts from the absorber surface to the therma 5vj7h l boundary layer of air m m thick on the outside of the a 5vj7h bsorber and to air tha j7h it passes behind the absorber. The boundary layer of air is drawn into a nearby perforation before the heat can escape by convection to the outside air. The heated air is then drawn from behind the absorber
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