Aqueous gel for heat storage pond and method for making the gel

摘要

A gel is formed by copolymerizing an acrylic monofunctional monomer and an acrylic bifunctional monomer in an aqueous solution exposed to an oxygen containing atmosphere. Spontaneous polymerization takes place in an atmosphere containing oxygen after the solution is placed in sunlight, or in the dark if the solution also contains a dissolved inorganic salt. The gel so formed is transparent to solar radiation, and is stable in the presence of such radiation and of temperatures in the vicinity of the boiling point of water. As a consequence, the gel is suitable for covering a heat storage liquid and thermally insulates the liquid against significant conductive heat loss to an ambient medium above the gel. By providing a myriad of small bubbles trapped in the gel, the insulating efficiency of the gel is increased without significantly interferring with the transmission of solar radiation to the heat storage layer below the gel. A gel having such bubbles is produced by including constituents in the solution from which the gel is formed which produce a gas (i.e., CO.sub.2).