Abstract: Apparatus (24), including a photovoltaic cell (22) and a concave primary reflector (26) configured to focus a first portion of incoming radiation toward a focal point (30). The apparatus also includes a secondary reflector (38), which is positioned between the concave primary reflector and the focal point so as to direct the focused radiation toward the photovoltaic cell, and which has a central opening (44) aligned with the photovoltaic cell. The apparatus further includes a transmissive concentrator (54), positioned so as to focus a second portion of the incoming radiation through the central opening onto the photovoltaic cell.

Abstract: A solar energy utilization unit comprises a solar radiation concentrating optics and a solar radiation receiver including first and second receiver components. The first receiver component is designed to convert into electric energy radiation in a first part of the solar spectrum, and the second receiver component is designed to convert into electric energy radiation in a second part of the solar spectrum different from said first part. The solar radiation concentrating optics comprises a concave primary reflector and a convex secondary reflector. The primary reflector is adapted to reflect incident solar radiation towards the secondary reflector, the secondary reflector is adapted to reflect radiation in the first part of the solar spectrum into the first receiver component and to transmit radiation in the second part of the solar spectrum into the second receiver component.

Abstract: A solar energy utilization unit comprises a solar radiation concentrating optics and a solar radiation receiver including a first receiver component designed to convert into electric energy radiation in a first part of the solar spectrum, and a second receiver components designed to convert into electric energy radiation in a second part of the solar spectrum which is different from said first part. The solar radiation concentrating optics comprises a concave primary reflector adapted to reflect incident solar radiation towards the secondary reflector, and a convex secondary reflector adapted to reflect radiation in the first part of the solar spectrum into the first receiver component and also to transmit radiation in the second part of the solar spectrum into the second receiver component. The primary reflector is formed with a centrally disposed opening, via which the first receiver component is adapted to receive the radiation reflected by the secondary receiver.

Abstract: A solar energy utilization unit comprises a solar radiation concentrating optics and a solar radiation receiver including first and second receiver components. The first receiver component is designed to convert into electric energy radiation in a first part of the solar spectrum, and the second receiver component is designed to convert into electric energy radiation in a second part of the solar spectrum different from said first part. The solar radiation concentrating optics comprises a concave primary reflector and a convex secondary reflector. The primary reflector is adapted to reflect incident solar radiation towards the secondary reflector, the secondary reflector is adapted to reflect radiation in the first part of the solar spectrum into the first receiver component and to transmit radiation in the second part of the solar spectrum into the second receiver component.