Solar energy collection

Abstract

Apparatus and methods for concentrating and collecting solar energy and for lowering the cost and increasing the efficiency of solar energy systems are disclosed. Solar energy is concentrated by economical refringent lenses or lens systems including fluid lenses and/or Fresnel-type lenses. The lenses concentrate the solar energy preferably along lines in continuous linear foci or in discrete foci at an elongated collector comprising one or more fluid-carrying conduits and one or more fluids therein. In one embodiment, a plurality of photovoltaic cells are located in or on the collector along the linear foci or at the discrete foci and operate at increased efficiency with heat being removed by the collector. Heating at the photoelectric cells is reduced by utilizing a fluid lens in which the lens fluid and lens plates absorb heat-producing infrared rays which otherwise would be converted to heat at the cells while permitting the electricity-producing luminous rays to pass to the cells with little absorption by the lens fluid and plates. A first fluid in the collector is heated by the concentrated solar energy and in a disclosed embodiment is used to heat a second fluid contiguous to the first fluid, the first fluid having a boiling point exceeding that of the second fluid. The first fluid is carried in an inner conduit while the second fluid is carried by an outer conduit which encloses the inner conduit and first fluid. Thus, the two fluids can be heated to different temperatures by a single concentrating system and used for different purposes. Energy is stored using two fluids of different boiling points. Also disclosed are methods and fixed and portable apparatus for distilling liquids including water containing salt or other substances by evaporation of the water and condensation of the water vapor wherein preferably the heat of condensation is recovered and heat in the condensate and brine is also preferably recovered. The invention also provides for assemblies of individual systems and subsystems to form larger and/or composite systems.