Abstract: A horizontal highly concentrated body of an aqueous solution constitute a solar pond in which the liquid body is divided into two horizontal strata (an upper and a lower stratum) of different density and temperature gradients. Between said strata is interposed a flowing middle level layer, said strata and said middle level layer having different functions.The lower stratum function as a solar heat trap for radiations to penetrate thereinto.The flowing middle level layer functions as a flowing solar heat trap mainly for heat lost by upward heat transmission from said lower stratum.The upper stratum functions as a flowing or stagnant insulating liquid cover preventing heat losses to the atmosphere of the sunrays penetrating said lower stratum and said middle level layer.

Abstract: Method and apparatus are described for the production of solid fuel and steam by drying moisture-containing solids, such as refuse and sludge cakes, in a multi-stage heating zone by using the moisture-containing solids as the feed-water in a direct contact countercurrent flow pressurized boiler. After vaporizing the bulk of the moisture in the heating zone of the boiler, the solid residue is further dried in a multi-stage flashing zone. From the upper end of the heating zone is removed a nearly saturated steam including the water vapor evaporated from the moisture-contained solids by the heat of cooling of the introduced superheated steam. A portion of the removed steam equal to the vaporized moisture is heated and then directed to a turbine, generating all the power required to operate the system. The bulk of the removed steam equal to the introduced superheated steam is compressed, reheated and recycled through the heating zone.