Light redirecting prism, a redirecting prismatic wall and a solar panel incorporating the same
The present disclosure relates to light redirecting elements in solar energy absorption systems and envisages a light redirecting prism, a redirecting prismatic wall and a solar panel incorporating the same. The light redirecting prism has three elongate surfaces. The incident surface receives incident parallel rays of light. The redirecting surface performs total internal reflection of the light travelling from the incident surface through a predetermined range of angles and thus redirect the light. The transmitting surface transmits the redirected light at a predetermined angle out of the prism and directs the light towards a solar energy absorbing device. Further, a redirecting prismatic wall can be constructed to comprise redirecting prisms. The light redirecting prism or redirecting prismatic wall can be used in solar panels for enhancing quantum of light incident on the PV cell of the panel.
1 . A light redirecting prism having at least three elongate surfaces including:
a. an incident surface configured to receive incident parallel rays of light;
b. a redirecting surface configured to perform total internal reflection of the light travelling from the incident surface through a predetermined range of angles and thus redirect the light, a first angle defined between the incident surface and a transmitting surface, said first angle being in the range of 80°-100°; and
c. said transmitting surface configured to transmit the redirected light at a predetermined angle out of said prism and to direct the light towards a solar energy absorbing device, a second angle defined between the incident surface and the redirecting surface, thus defining a third angle defined between the redirecting surface and the transmitting surface, said second angle being in the range of 45°-55°; and
wherein, said transmitting surface includes a secondary redirecting profile provided thereon, said secondary redirecting profile spanning at least a lower part of said transmitting surface and extending up to an operative lower edge of said transmitting surface, said secondary redirecting profile provided along the length of said transmitting surface, said secondary redirecting profile being configured to redirect towards the adjacent solar energy absorbing device, that component of the redirected rays coming from said transmitting surface which would get transmitted in a shadow region of said prism or transmitted back in the air or transmitted within the prism boundary in the absence of said secondary redirecting profile, said shadow region being that region below said redirecting prism between the lower edge of the transmitting surface of said prism and the corresponding solar energy absorbing device.
2 . The redirecting prism as claimed in claim 1 , wherein said secondary redirecting profile comprises at least one ridge whose edge lies in a horizontal plane or a plurality of reedings or flutings having a plurality of semicylindrical protrusions or depressions respectively, with axes of said protrusions or said depressions being parallel to the axis of the transmitting surface of said prism.
3 . The redirecting prism as claimed in claim 1 , wherein said redirecting prism is made of a material with a refractive index of 1.51, the material being selected from the group consisting of polymethyl methacrylate, acrylic, styrene, polycarbonate, glass, styrene methyl methacrylate, polycarbonate, styrene, styrene acrylic copolymers or derivatives of these materials.