A method for determining relative degrees of reflectance of a measurement surface, having the method steps of applying measurement radiation to the measurement surface, such that a measurement spot is produced on the management surface, moving the measurement spot along at least a first straight measurement spot path, over the measurement surface in accordance with a first path movement and along a second straight measurement spot path with a second path movement, recording a first and second image sets of a plurality of locally resolved images of the measurement surface during the first path movement and the second path movement. An evaluation is carried out at intersection points, whose location points on the management surface are defined by evaluation lines, wherein a first group of straight evaluation lines within the first measurement path region and a second group of straight evaluation lines within the second measurement path region are predefined and/or determined. The evaluation lines of the first group are parallel to the first measurement spot path and the evaluation lines of the second group are parallel to the second measurement spot path, and each first group evaluation line has an intersection point with each second group evaluation line. For each intersection point, a maximum greyscale value is determined, and relative degrees of reflectance of the measurements surface are determined at least on a subset of the intersection points, depending on these greyscale values.

A method for determining relative degrees of reflectance of a measurement surface, having the method steps of applying measurement radiation to the measurement surface, such that a measurement spot is produced on the management surface, moving the measurement spot along at least a first straight measurement spot path, over the measurement surface in accordance with a first path movement and along a second straight measurement spot path with a second path movement, recording a first and second image sets of a plurality of locally resolved images of the measurement surface during the first path movement and the second path movement. An evaluation is carried out at intersection points, whose location points on the management surface are defined by evaluation lines, wherein a first group of straight evaluation lines within the first measurement path region and a second group of straight evaluation lines within the second measurement path region are predefined and/or determined. The evaluation lines of the first group are parallel to the first measurement spot path and the evaluation lines of the second group are parallel to the second measurement spot path, and each first group evaluation line has an intersection point with each second group evaluation line. For each intersection point, a maximum greyscale value is determined, and relative degrees of reflectance of the measurements surface are determined at least on a subset of the intersection points, depending on these greyscale values.

A reflective concentrator can include a primary reflector and a secondary reflector located radially outward of the primary reflector. The primary reflector can be a rotationally-symmetric, convex conical shape, radial sections of which may include an off-axis parabolic reflector with a focal point radially outward of the primary reflector. A secondary reflector may be located radially outward of the primary reflector, and may include a rotationally symmetric section of a toroidal space surrounding the primary reflector. In some embodiments, the secondary reflector may be convex or concave. Incident sunlight generally aligned with a rotational axis of symmetry of the primary reflector may be reflected off of the primary reflector, off of the secondary reflector, and back towards a point near the central peak of the primary reflector. The reflective concentrator may be aerodynamically stable, and may include an aerodynamic fairing on its read side to further increase the aerodynamic stability of the structure.

A reflective concentrator can include a primary reflector and a secondary reflector located radially outward of the primary reflector. The primary reflector can be a rotationally-symmetric, convex conical shape, radial sections of which may include an off-axis parabolic reflector with a focal point radially outward of the primary reflector. A secondary reflector may be located radially outward of the primary reflector, and may include a rotationally symmetric section of a toroidal space surrounding the primary reflector. In some embodiments, the secondary reflector may be convex or concave. Incident sunlight generally aligned with a rotational axis of symmetry of the primary reflector may be reflected off of the primary reflector, off of the secondary reflector, and back towards a point near the central peak of the primary reflector. The reflective concentrator may be aerodynamically stable, and may include an aerodynamic fairing on its read side to further increase the aerodynamic stability of the structure.

A method for controlling the orientation of a single-axis solar tracker orientable about an axis of rotation, including observing the evolution over time of the cloud coverage above the solar tracker; determining the evolution over time of an optimum inclination angle of the solar tracker substantially corresponding to a maximum of solar radiation on the solar tracker, depending on the observed cloud coverage; predicting the future evolution of the cloud coverage based on the observed prior evolution of the cloud coverage; calculating the future evolution of the optimum inclination angle according to the prediction of the future evolution of the cloud coverage; servo-controlling the orientation of the solar tracker according to the prior evolution of the optimum inclination angle and depending on the future evolution of the optimum inclination angle.

A method for controlling the orientation of a single-axis solar tracker orientable about an axis of rotation, including observing the evolution over time of the cloud coverage above the solar tracker; determining the evolution over time of an optimum inclination angle of the solar tracker substantially corresponding to a maximum of solar radiation on the solar tracker, depending on the observed cloud coverage; predicting the future evolution of the cloud coverage based on the observed prior evolution of the cloud coverage; calculating the future evolution of the optimum inclination angle according to the prediction of the future evolution of the cloud coverage; servo-controlling the orientation of the solar tracker according to the prior evolution of the optimum inclination angle and depending on the future evolution of the optimum inclination angle.

An extremely low cost solar concentrator made of membranes or films is inflated into a Compound Parabolic Concentrator (CPC) a non-image concentrator. The portion of the inflatable concentrator, which is shaped into a CPC concentrator, is formed with reflective membranes or films, and the portions of the inflatable concentrator on the top of CPC and on the bottom of the concentrator are made of clear membranes or films. The incident light including parallel rays of light and diffuse light, as long as falling into the half acceptance angle of the CPC, will be concentrated to the bottom exit aperture of the CPC. Therefore, this type concentrator reduces the requirement to the accuracy of tracking for concentration. In addition, this type of concentrator demonstrates more tolerance to shape distortion for concentration than imaging system.

An extremely low cost solar concentrator made of membranes or films is inflated into a Compound Parabolic Concentrator (CPC) a non-image concentrator. The portion of the inflatable concentrator, which is shaped into a CPC concentrator, is formed with reflective membranes or films, and the portions of the inflatable concentrator on the top of CPC and on the bottom of the concentrator are made of clear membranes or films. The incident light including parallel rays of light and diffuse light, as long as falling into the half acceptance angle of the CPC, will be concentrated to the bottom exit aperture of the CPC. Therefore, this type concentrator reduces the requirement to the accuracy of tracking for concentration. In addition, this type of concentrator demonstrates more tolerance to shape distortion for concentration than imaging system.

An energy concentrating apparatus includes: a mounting platform, a mounting support, a rotating support, a reflective mirror, an arc-shaped slide rail, a linking rod, a sliding parts, a drive device, and a pull rope. The mounting support is located on the mounting platform. A rotation shaft of each rotating support is rotatably located on the corresponding mounting support, and a rotation shaft of each reflective mirror is rotatably located on the corresponding rotating support. The arc-shaped slide rail is located on the mounting platform, and the sliding parts is slidably located in the arc-shaped slide rail, the linking rod is connected to the sliding parts and the reflective mirror respectively, and a curvature of the arc-shaped slide rail is different such that the reflective mirror rotates towards a different direction.

An energy concentrating apparatus includes: a mounting platform, a mounting support, a rotating support, a reflective mirror, an arc-shaped slide rail, a linking rod, a sliding parts, a drive device, and a pull rope. The mounting support is located on the mounting platform. A rotation shaft of each rotating support is rotatably located on the corresponding mounting support, and a rotation shaft of each reflective mirror is rotatably located on the corresponding rotating support. The arc-shaped slide rail is located on the mounting platform, and the sliding parts is slidably located in the arc-shaped slide rail, the linking rod is connected to the sliding parts and the reflective mirror respectively, and a curvature of the arc-shaped slide rail is different such that the reflective mirror rotates towards a different direction.