Abstract: Power is produced by a power plant using a salt-water solar pond comprising an upper wind-mixed layer, a halocline and a lower convective heat storage layer. The power plant includes a heat engine for utilizing heat present in the heat storage layer of the solar pond and a condenser, which preferably is cooled by liquid droplets. In accordance with a specific embodiment of the invention the power plant is positioned within the solar pond and a flash evaporator is used in the heat engine to produce steam which is supplied to a turbine connected to a generator, the heat depleted steam exiting from the turbine and being cooled by liquid droplets in a direct-contact condenser. The size of the droplets is selected such that the heat extracted in the condenser penetrates the majority of the liquid content of most of the droplets.

Abstract: Fluid leakage through soil in a region thereof is controlled by sequentially passing over the region to dig a plurality of parallel, laterally displaced grooves in the surface. Soil dug from each groove is temporarily stored, and a strip of sheet material is laid over a groove as it is created during each pass, the width of the strip being greater than the width of the groove. Thereafter, the temporarily stored soil is deposited on the strip such that it is covered with soil except along one edge, the other edge of the strip overlying the uncovered edge of an adjacent strip laid down during a previous pass over the region. As a consequence, a first layer of overlapping strips of sheet material covered with soil is installed over the region.

Abstract: The turbidity of a fluid is reduced by adding a treatment solution containing a flocculation agent to said fluid. The treatment solution has a density different from that of the fluid. It is added at selected locations in the fluid such that the difference in densities will cause the treatment solution to be uniformly distributed throughout the fluid to be treated thereby causing flocs to be uniformly distributed throughout the fluid. In this way, a fluid can be treated in situ, rather than transported to a separate location, and mechanically mixed with a flocculation agent. This technique has particular application in the preparation and maintenance of solar ponds.

Abstract: A halocline in a salt-water solar pond is protected against the effect of wind by dividing the upper portion of the pond into essentially separate cells or units that are segregated, but without hydraulically altering the operation of the pond. Specifically, a floating grid of expandable partitions is placed in the pond, so that an upper surface of each partition protrudes from the water, and the lower surface of each partition extends into the halocline, the liquid in the upper portion of each cell formed by the grid being essentially segregated. Provision is made for periodically expanding the partitions in order to flake off salt that precipitates on the partitions.

Abstract: The wind-mixed layer of a salt-water solar pond is dynamically stabilized against wind by creating a two-layer flow regime in the wind-mixed layer. Lighter less dense water flows in one direction adjacent the surface of the pond and heavier, more dense water flows in the opposite direction beneath the lighter water. The two-layer flow regime can be created by selectively connecting the wind-mixed layer to a source of brine whose density exceeds the average density of water in the wind-mixed layer. Alternatively, the two-layer flow regime is created by selectively adding fresher water to the surface of the solar pond at the surface thereof to replace evaporation losses.

Abstract: Water in a solar pond power plant is chlorinated in order to help maintain the transparency of the wind-mixed layer, to suppress microbial activity at all levels of the pond, and to reduce fouling of the boiler which receives hot brine from the heat storage layer of the pond. In one aspect of the invention, chlorine is injected into the water in the wind-mixed layer, in the halocline, and/or in the heat storage layer. Injection into the wind-mixed layer and into the heat storage layer is possible by reason of the flow of this water outside the pond to supply the boiler and condenser of the power plant, thus providing accessibility to liquid chlorine treatment. The halocline is chlorinated by using vertically adjustable intake and discharge diffusers positioned in the halocline and exchanging the water in a stratum. In a second aspect of the invention, in-situ electrolysis is utilized for selectively chlorinating the pond at various levels or locations.

Abstract: The wind-mixed layer of a salt-water solar pond is dynamically stabilized against wind by creating a two-layer flow regime in the wind-mixed layer. Lighter less dense water flows in one direction adjacent the surface of the pond and heavier, more dense water flows in the opposite direction beneath the lighter water. The two-layer flow regime can be created by selectively connecting the wind-mixed layer to a source of brine whose density exceeds the average density of water in the wind-mixed layer. Alternatively, the two-layer flow regime is created by selectively adding fresher water to the surface of the solar pond at the surface thereof to replace evaporation losses.

Abstract: A halocline is maintained in open body of salt water at a depth to which a significant amount of solar radiation penetrates by inducing an upward vertical flow in the body of water sufficient to counter wind-mixing and molecular diffusion thereby establishing an ascending or rising solar lake. The upward flow is induced by injecting into the body of water a concentrate with a density greater than the density of liquid at the lower end of the halocline, the concentrate being formed by evaporating liquid drawn from the surface of the body of water. The halocline suppresses convention currents and allows solar radiation to heat the halocline as well as a layer of liquid therebelow to temperatures significantly higher than the surface temperature. Heat for useful work can be extracted from the heat storage layer beneath the halocline.

Abstract: Make-up water contaminated with nutrients is pretreated by establishing a stagnant pond of brackish water having an upper wind-mixed layer exposed to solar radiation and of relatively low, uniform salinity, an intermediate halocline whose salinity increases monotonically with depth, and a lower collection layer of relatively high, uniform salinity. Make-up water contaminated with nutrients is added to the wind-mixed layer wherein the nutrients support the growth of photosynthetic microbes. The wind-mixed layer is provided with Artemia salina (brine shrimp) that feed on the photosynthetic microbes growing in the wind-mixed layer and extrude fecal pellets of a density in excess of the density of at least the upper layer of the pond, whereby the pellets sink below the wind-mixed layer, and preferably to the collection layer. Upward diffusion from the collection layer into the wind-mixed layer of the disintegrated constituents of the fecal pellets is suppressed by reason of the stratified nature of the halocline.

Abstract: A halocline is maintained in open body of salt water at a depth to which a significant amount of solar radiation penetrates by inducing an upward vertical flow in the body of water sufficient to counter wind-mixing and molecular diffusion thereby establishing an ascending or rising solar lake. The upward flow is induced by injecting into the body of water a concentrate with a density greater than the density of liquid at the lower end of the halocline, the concentrate being formed by evaporating liquid drawn from the surface of the body of water. The halocline suppresses convention currents and allows solar radiation to heat the halocline as well as a layer of liquid therebelow to temperatures signficantly higher than the surface temperature. Heat for useful work can be extracted from the heat storage layer beneath the halocline.

Abstract: Apparatus for measuring the density profile of a layer of liquid includes a plurality of individual tubes arranged in side-by-side fashion, each of the tubes having an inlet opening in its lower end. A vacuum manifold is connected to the apertured upper ends of the tubes. The apertures in the lower ends of the tubes are vertically staggered and the tubes are vertically oriented with the lower ends of the tubes immersed in the liquid, so that the inlet openings are differentially spaced from the surface of the liquid. The application of a vacuum to the tubes causes liquid from the different levels to be drawn into the tubes, the height of the liquid in the tubes above the surface being proportional to the density of the liquid drawn into the tubes through the inlets.

Abstract: A pond construction, especially useful for non-convective solar ponds, having a multi-layer bottom in order to minimize seepage of liquid through the pond bottom. Liquid which permeates the multi-layer construction is pumped back into the pond.

Abstract: A method of changing the salt content of a solution is described by including the salt in a nonconvective solar pond heated by solar radiation and having stable salt-concentration and temperature gradients increasing from the top to the bottom of the pond, the bottom layer of the pond being a substantially saturated solution at a predetermined temperature. A feed solution containing the salt is introduced directly into the bottom layer and is circulated through the bottom layer. The predetermined temperature of the bottom layer is different from the initial temperature of the feed solution when introduced into the pond bottom layer and is selected to effect a change in solubility, and thereby a change in the salt content, of the feed solution by causing salt in the feed solution to be precipitated therefrom, or additional salt to be dissolved therein.