Compact LCPV solar electric generator
A compact low concentration photovoltaic (LCPV) apparatus totally enclosed in a protective clear dome against harsh environment without active cooling. A conical mirror reflector, a circular lens refractor and a planar circular crystalline silicon photovoltaic solar panel rotate simultaneously inside the dome to concentrate sun rays and instantly produce electricity. The mirror increases electrical current three times and the lens increases one time for total four times using low overall concentration of five to twenty times sun. The lens is offset from the plane parallel to the photovoltaic solar panel, while the panels forming the mirror are angled offset to a center axis perpendicular to the solar panel. The optical assembly and solar panel are mounted in a conical aluminum cage which is pivoted from a rotary turntable for the daily azimuth and altitude rotations. The dual axis movements consist of irregular intermittent increments of less than one second “on time” and less than two minutes “off time” while following the sun path. The electrical power produced is at least two times more than from fixed conventional crystalline silicon solar panel occupying the same planar surface area. LCPV dual tracking systems offer reduced electricity generation costs, reduced installation costs and increased flexibility in deployment.
1. An apparatus comprising:
a base for mounting a device perpendicularly to a structure or for insertion perpendicularly into the ground;
a turntable mounted upon the base with a conical frame assembly for mounting and alignment of a planar, circular solar panel and an optical assembly, the optical assembly comprised of a conical mirror and a lens; a pivot structure erected on the turntable for pivoting the conical frame assembly;
a biaxial sensor tracker and a biaxial controller for tracking a position of the sun and controlling both an azimuth mechanism and an altitude mechanism; the azimuth mechanism for adjusting a rotational position of the turntable and the conical frame assembly with respect to the base and the altitude mechanism for adjusting an elevation rotation of the conical frame assembly with respect to the turntable;
a plurality of mono-crystalline or poly-crystalline silicon photovoltaic (PV) cells forming the solar panel attached to a bottom of the conical frame assembly and responsive to incoming radiation within predetermined first and second solar ray wavelength ranges and characterized by first and second dimensions along axes perpendicular to one another in a plane parallel to a planar surface of the solar panel; an outer diameter of the solar panel is about 40% smaller than an outer diameter of the lens and about two times smaller than a slope length of the mirror; the solar panel rotates with the optical assembly while in operation;
the conical mirror having twelve sides, each side comprised of a panel, the conical mirror comprising an inner surface and an outer surface and having a first end disposed towards the solar panel and a distal end disposed towards the lens, the distal end comprising an outer diameter which is larger than any other diameter of the conical mirror, the first end of the mirror following a circle to closely match an outer perimeter formed by the PV cells of the solar panel; an inner surface of the conical mirror being reflective to radiation within the predetermined first wavelength range through a 6 inch air gap clearance between the outer diameter of the lens and the outer diameter of the distal end of the conical mirror; reflected rays through the air gap onto the conical mirror overlap the predetermined second wavelength range refracted by the lens onto the solar panel; wherein in operation the panel of each side of the conical mirror along which the first end and distal end are disposed are offset at a predetermined outward angle between 15° and 30° with respect to a perpendicular center axis going through a center of the lens and a center of the solar panel;
the lens positioned within the outer diameter of the distal end of the conical mirror and transmissible to a portion of the incoming radiation which is within the predetermined second wavelength range that falls within the predetermined first wavelength range area reflected by the conical mirror, the lens characterized by third and fourth dimensions along the axes perpendicular to one another in the plane parallel to the planar surface of the solar panel, wherein both the third and fourth dimensions are larger than the first and second dimensions, wherein in operation the lens has a predetermined separation from the solar panel and a plane of the lens is further transversely offset by a predetermined angle with respect to the planar surface of the solar panel; the lens is fixed and tilted permanently between 1° and 25° in relationship to the planar surface of the solar panel; the lens is composed of four double convex concentric rings sequentially stepped outward from the center of the lens;
an exhaust fan to remove water condensation inside the apparatus during cooler days operation;
a transparent environmental protective dome to protect against harsh weather, thermoformed from clear PETG (polyethylene terephthalate glycol), CAB (cellulose acetate butyrate), SAN (styrene acrylonitrile resin), co-polyester, vinyl, acrylic or polycarbonate sheet; the transparent dome is transmissible to solar radiation within the predetermined first wavelength range.
2. The apparatus according to claim 1 wherein:
the outer diameter of the solar panel is about 16 inches and the predetermined separation of the lens and the solar panel is about 19 inches.
3. The apparatus according to claim 1 , wherein:
the conical mirror is a truncated conical mirror, wherein the twelve sides of the truncated conical mirror consist of six rectangular mirror panels alternating with six trapezoidal mirror panels; the first end of the conical mirror is about 1 to 2 mm from the outer perimeter of the PV cells forming the solar panel; the conical mirror height is no less than 22 inches;
the conical mirror is made with aluminum coated PETG sheets on ¾ inch thick polyisocyanurate foam insulation boards.
4. The apparatus according to claim 1 , wherein:
the solar panel, conical mirror and lens form part of a permanently fixed aligned assembly that under direction of a tracker and controller rotate simultaneously according to a measure of time and a measure of sun position; wherein the controller will switch automatically back and forth between two control modes to follow the path of the sun, one mode for a visible sun and the other mode when the sun is not visible.
5. The apparatus according to claim 1 , wherein:
cooling of the solar panel is absent of active temperature stabilization and active temperature management.
6. The apparatus to claim 1 , wherein:
the lens is injection molded with PETG (polyethlene terephthalate glycol), CAB (cellulose acetate butyrate), SAN (styrene acrylonitrile resin), co-polyester, vinyl, acrylic or polycarbonate polymers.
7. The apparatus according to claim 1 , wherein:
the base is made of ABS (acrylonitrile butadiene styrene) structural foam, vinyl plastics or aluminum; the base comprising of an aluminum post for mounting the apparatus perpendicularly to a structure or insertion perpendicularly into the ground;
the turntable is made of aluminum; the conical frame assembly is made of aluminum.
8. The apparatus according to claim 2 , wherein:
a two control mode controller moves the conical frame assembly according to a measure of time and a measure of sun position; the first control mode senses the location of the sun and creates irregular intermittent daily horizontal (azimuth) and altitude (zenith) movements by bi-axial tracker electronics and two 24 hour programmable logic controllers when the sun is visible; the first control mode switches automatically to the second control mode when the sun is not visible and the intermittent daily horizontal (azimuth) and altitude (zenith) movements become regular short strokes created by the two 24 hour programmable logic controllers only to follow an average path of the sun between end of summer and end of spring;
the tracker electronics will follow the path of the sun at any point in time once the sun appears and cause the two control mode controller to switch back to the first control mode;
the azimuth and altitude mechanisms are driven with DC motors with rated torque less than 2 Newton centimeter and less than 100 milliamps.
9. The apparatus according to claim 8 , wherein:
cooling of the solar panel is absent of active temperature stabilization and active temperature management and a passive heat sink is only required for the solar panel.
10. The apparatus according to claim 2 , wherein:
the dome has a semi spherical shape.