Patent Application
20070289622
So that the manner in which the features and advantages of the present invention, which will become apparent, are attained and can be understood in more detail, more particular description of the invention briefly summarized above may be had by reference to the embodiments thereof that are illustrated in the appended drawings which form a part of this specification. It is to be noted, however, that the drawings illustrate only some embodiments of the invention and therefore are not to be considered limiting of its scope as the invention may admit to other equally effective embodiments.
Referring to
A package 21 for converting solar energy is positioned adjacent the lower opening 15 of the housing 11 opposite the cover lens 17. In one embodiment, the package 21 comprises a photovoltaic (PV) cell 23 for converting solar energy into electrical power, a thermionic (TI) or thermoelectric (TE) cell 25 (hereinafter, either or both are referred to as “TE cell”) for converting waste heat into electrical power via thermionic or thermoelectric conversion, and a water circulation system 27 to remove excess thermal energy for various heating purposes. With the development of high temperature, semiconductor-based PV units, water circulation system 27 also may provide thermal-steam power energy generation.
In one embodiment, the PV cell 23 is located adjacent the aperture 15 and has an efficiency rating of about 6% to 34% for producing electrical power from solar energy. The water circulation system 27 maintains the PV cell 23 at an acceptable temperature for long life. In addition, the water circulation system 27 has an efficiency rating of about 25% to 50% for absorbing heat from solar energy. The TI or TE cell 25 has an efficiency rating of about 2% to 25% for producing electrical power from solar energy. Thus, overall, the package 21 harnesses more than about 50% of the solar energy incident on the package 21.
In the embodiment of
In one alternate embodiment (
In another alternate embodiment (
Alternatively, an optional optical cover 230 may be provided for the PV cell 223. Optical cover 230 may be treated with anti-reflective coatings and also may incorporate phosphors to shift the wavelength of incident radiation to wavelengths that are more efficiently converted by the PV cell 223. The inclusion of phosphor is just in front of the PV cell, rather than elsewhere in the solar energy path where diffusion would reduce power flux to the target cells.
In another alternate embodiment (
In still other embodiments (
Referring now to
The method also may comprise providing the housing with a shape selected from the group consisting of parabolic, conical, round, linear, square, and hexagonal reflectors; and the cover lens is selected from the group consisting of a fresnel lens and a convex lens, and is positioned adjacent an incoming solar radiation end of the housing. Alternatively, the method may comprise providing the housing with an aperture located opposite the cover lens; and further comprising locating the PV cell adjacent the aperture, the PV cell having an efficiency rating of about 6% to 34% for producing electrical power from solar energy; and the TE cell having an efficiency rating of about 2% to 25% for producing electrical power from solar energy.
In another embodiment, the method may comprise reducing a temperature of the PV cell with the water circulation system to extend a useful life of the PV cell, the water circulation system having an efficiency rating of about 25% to 50% for absorbing heat from solar energy, and the package harnessing over 50% of the solar energy incident on the package; or positioning the TE cell adjacent the PV cell opposite the housing, and positioning the water circulation system adjacent the TE cell opposite the PV cell; or positioning the TE cell between the PV cell and the cover lens within a volume of the housing, and positioning the water circulation system adjacent the PV cell and adjacent the TE cell, opposite the incident solar energy; or positioning the housing between the PV cell and the TE cell for directing reflected solar energy toward the TE cell, positioning the water circulation system adjacent non-irradiated sides of the PV and TI cells, and forming an aperture in the housing for permitting solar energy not absorbed by the TE cell to be directed toward the PV cell.
The method may further comprise covering the PV cell with an optical phosphor that shifts non-optimum wavelengths to optimum wavelengths for greater energy conversion, and collimating solar flux with a secondary reflector towards a prism to separate wavelengths and a slotted thermal plane passes PV efficient wavelengths to the PV cell and absorbs the remaining wavelengths for conduction to the TE cell; or conducting thermal energy with a heat pipe from a slotted wavelength separator to the TE cell, and absorbing non-optimum PV wavelengths with a stack of wavelength specific filters, and transferring them to a heat pipe that conducts thermal energy to the TE cell; or concentrating spectral solar radiation with a primary fresnel lens to a secondary concave collimating lens and directing a light beam to the prism for separation into wavelengths for enhanced solar energy conversion; and wherein the TE cell is a heat absorption cell for a system selected from the group consisting of a thermal-steam powered energy generation system and a Sterling engine system.
While the invention has been shown or described in only some of its forms, it should be apparent to those skilled in the art that it is not so limited, but is susceptible to various changes without departing from the scope of the invention. For example, each embodiment requires the use of a conventional sun tracking system, including azimuth, elevation, etc., such as those known in the art.
