Bifacial Solar Cell Array
First and second solar panels are mounted in an operative position. Each panel includes an upward-facing photovoltaic surface and a downward-facing photovoltaic surface that are configured to photovoltaically generate electricity from light. The downward-facing photovoltaic surface is spaced above a reflective surface. The first and second panels are spaced apart in a first direction by a spacing distance that is about 25% to about 100% of the width of the first panel in the first direction. Some downwardly-directed light rays can strike the upward-facing photovoltaic surfaces of the panels. Other downwardly-directed light rays can pass between the first and second panels and be reflected upward by the reflective surface to strike the downward-facing photovoltaic surfaces of the panels.
1 . An apparatus comprising:
first and second solar panels mounted in an operative position, each panel including an upward-facing photovoltaic surface and a downward-facing photovoltaic surface that are configured to photovoltaically generate electricity from light, the downward-facing photovoltaic surface being spaced above a reflective surface;
the first and second panels being spaced apart in a first direction by a spacing distance that is 25%-100% of the width of the first panel in the first direction, for some downwardly-directed light rays to strike the upward-facing photovoltaic surfaces of the panels and for other downwardly-directed light rays to pass between the first and second panels and be reflected upward by the reflective surface to strike the downward-facing photovoltaic surfaces of the panels.
2 . The apparatus of claim 1 wherein the reflective surface is a mirror surface.
3 . The apparatus of claim 1 wherein the reflective surface is a light-diffusing surface.
5 . The apparatus of claim 1 wherein the reflective surface is a ground surface.
6 . The apparatus of claim 1 wherein the reflective surface is a roof surface.
7 . The apparatus of claim 1 wherein the reflective surface is configured to be walked on.
8 . The apparatus of claim 1 wherein the reflective surface is secured to the first panel.
9 . The apparatus of claim 1 wherein the reflective surface not secured to the first panel.
10 . The apparatus of claim 1 wherein a portion of the reflective surface is located between the panels.
11 . The apparatus of claim 1 wherein a portion of the reflective surface is directly beneath the downward-facing photovoltaic surface.
12 . The apparatus of claim 1 wherein the height of the downward-facing photovoltaic surface above the reflective surface is about 25% to about 100% of the width of the panel in the first direction.
13 . The apparatus of claim 1 wherein the horizontal area defined by and between the first and second panels is about 25% to about 100% of the horizontal area covered by the first panel.
14 . The apparatus of claim 1 wherein the width of the first panel in the first direction and the width of the first panel in a second direction perpendicular to the first direction differ by less than about 5%.
15 . The apparatus of claim 1 wherein the panels are secured in place.
16 . The apparatus of claim 1 wherein are not secured in place.
17 . The apparatus of claim 1 wherein the photovoltaic surfaces of the first panel are electrically interconnected with the photovoltaic surfaces of the second panel.
18 . The apparatus of claim 1 wherein each of the panels includes legs that engage the reflective surface to space the downward-facing photovoltaic surface above the reflective surface.
19 . The apparatus of claim 1 wherein the panel is configured to retain the upward-facing and downward-facing photovoltaic surfaces in a fixed orientation.
20 . The apparatus of claim 19 wherein the fixed orientation is horizontal.
21 . The apparatus of claim 1 wherein the upward-facing and downward-facing photovoltaic surfaces of the first panel are each provided by multiple photocells.
22 . The apparatus of claim 1 wherein the upward-facing and downward-facing photovoltaic surfaces of the first panel are provided by one or more bifacial photovoltaic units.
23 . The apparatus of claim 1 wherein the upward-facing and downward-facing photovoltaic surfaces of the first panel are radially opposite surface portions of a cylindrical photovoltaic surface.
24 . The apparatus of claim 23 wherein the cylindrical photovoltaic surface is one of multiple cylindrical photovoltaic surfaces of the first panel.
25 . The apparatus of claim 1 further comprising a third solar panel mounted in an operative position, the third panel including an upward-facing photovoltaic surface and also a downward-facing photovoltaic surface that is spaced above the reflective surface;
the first and third panels being spaced apart in a second direction, perpendicular to the first direction, by a spacing distance that is about 25% to about 100% of the width of the first panel in the second direction, for some downwardly-directed light rays to strike the upward-facing photovoltaic surface of the third panels and for other downwardly-directed light rays to pass between the first and third panels and be reflected upward by the reflective surface to strike the downward-facing photovoltaic surfaces of the first and third panel.