A solar collector can comprise: a polymeric housing; a polymeric cover attached to the housing defining an internal volume of the solar collector; a solar energy absorber attached to the housing and located within an area defined by the housing and the cover; wherein the housing comprises a flexible sealing member; and wherein the cover comprises a honeycomb structure.

Various implementations include solar thermal energy collection system comprising a solar energy concentrator, a heat transfer fluid, an absorber pipe. The absorber pipe includes a pipe wall and has a central longitudinal axis. The pipe wall has an inner surface and an outer surface. The inner surface has a first contour defining alternating peaks and troughs along a length of the absorber pipe. The outer surface has a second contour defining alternating peaks and troughs along the length of the absorber pipe. The inner surface defines the entire flow path for the heat transfer fluid through the absorber pipe. The first contour, as viewed through an axial cross section of the absorber pipe, forms sinusoidal waves on each side of and spaced apart from the central longitudinal axis. The sinusoidal waves on each side of the central longitudinal axis are symmetrical with respect to the central longitudinal axis.

A roof or wall comprising an insulating selective surface (1) for the use of transferring net heat energy into or out of an enclosure, such as a building. The insulating selective surface comprises at least one transparent cover (2) that comprises a chamber (9), and in the chamber is a moveable plate (4) comprising a plurality of surfaces (5, 6). At least one of the surfaces is a selective surface which can be moved to substantially face the sky, or moved to face away from the sky. The device insulates the enclosure from conductive losses, while using the sun to heat the enclosure, or the cold of deep space to cool the enclosure depending on how the plate is moved.

A roof or wall comprising an insulating selective surface (1) for the use of transferring net heat energy into or out of an enclosure, such as a building. The insulating selective surface comprises at least one transparent cover (2) that comprises a chamber (9), and in the chamber is a moveable plate (4) comprising a plurality of surfaces (5, 6). At least one of the surfaces is a selective surface which can be moved to substantially face the sky, or moved to face away from the sky. The device insulates the enclosure from conductive losses, while using the sun to heat the enclosure, or the cold of deep space to cool the enclosure depending on how the plate is moved.

Provided is a solar collector that captures and utilizes solar energy and includes a plurality of vacuum tubes which are disposed by extending horizontally and are disposed parallel to each other with a predetermined distance; and a reflection plate having a substantially planar shape, which reflects solar light on an opposite side of the sun with respect to the plurality of vacuum tubes, in which the reflection plate includes a reflection surface having a serrated section at a corresponding position between vacuum tubes adjacent to each other, and in the reflection surface, one face of a serration forms a first reflection surface that reflects the solar light to the vacuum tube on a lower side among the vacuum tubes adjacent to each other.

A double line focusing solar energy collection apparatus of the present invention includes a heat collector, a secondary concentrator, and a bracket. The heat collector includes a primary concentrator and a heat collection tube, in which the primary concentrator has a focus line. The secondary concentrator has a focus line. The bracket supports the primary concentrator, the heat collection tube, and the secondary concentrator. The heat collection tube is located between the primary and secondary concentrators and located on the focus lines of the secondary and primary concentrators. The primary concentrator is a paraboloid reflector or Fresnel reflector. The secondary concentrator is a paraboloid reflector or Fresnel reflector. By adding the secondary concentrator, it achieves low light loss and high heat collection efficiency, and erosion of the heat collection tube by sand, rain, and snow can be effectively prevented, thereby extending the lifetime of the heat collection tube effectively.

A double line focusing solar energy collection apparatus of the present invention includes a heat collector, a secondary concentrator, and a bracket. The heat collector includes a primary concentrator and a heat collection tube, in which the primary concentrator has a focus line. The secondary concentrator has a focus line. The bracket supports the primary concentrator, the heat collection tube, and the secondary concentrator. The heat collection tube is located between the primary and secondary concentrators and located on the focus lines of the secondary and primary concentrators. The primary concentrator is a paraboloid reflector or Fresnel reflector. The secondary concentrator is a paraboloid reflector or Fresnel reflector. By adding the secondary concentrator, it achieves low light loss and high heat collection efficiency, and erosion of the heat collection tube by sand, rain, and snow can be effectively prevented, thereby extending the lifetime of the heat collection tube effectively.

Various implementations include solar thermal energy collection system comprising a solar energy concentrator, a heat transfer fluid, an absorber pipe. The absorber pipe includes a pipe wall and has a central longitudinal axis. The pipe wall has an inner surface and an outer surface. The inner surface has a first contour defining alternating peaks and troughs along a length of the absorber pipe. The outer surface has a second contour defining alternating peaks and troughs along the length of the absorber pipe. The inner surface defines the entire flow path for the heat transfer fluid through the absorber pipe. The first contour, as viewed through an axial cross section of the absorber pipe, forms sinusoidal waves on each side of and spaced apart from the central longitudinal axis. The sinusoidal waves on each side of the central longitudinal axis are symmetrical with respect to the central longitudinal axis.

A double-line focusing solar energy collection apparatus, comprising: a heat collector (1) which comprises a primary concentrator (11) and a heat collection tube (12), the primary concentrator (11) having a focus line; a secondary concentrator (3), having a focus line; and a support (2), for supporting the primary concentrator (11), the heat collection tube (12), and the secondary concentrator (3). The heat collection tube (12) is located between the secondary concentrator (3) and the primary concentrator (11), and is located on the focus lines of the primary concentrator (11) and the secondary concentrator (3).

A double-line focusing solar energy collection apparatus, comprising: a heat collector (1) which comprises a primary concentrator (11) and a heat collection tube (12), the primary concentrator (11) having a focus line; a secondary concentrator (3), having a focus line; and a support (2), for supporting the primary concentrator (11), the heat collection tube (12), and the secondary concentrator (3). The heat collection tube (12) is located between the secondary concentrator (3) and the primary concentrator (11), and is located on the focus lines of the primary concentrator (11) and the secondary concentrator (3).