A solar water heater absorber absorbs the sun's energy on the surface of a twin-walled polycarbonate panel and conducts the heat from the sun through the panel wall into fluid flow through channels of the panel. The panel is an extruded polycarbonate glazing material that consists of two panes connected by longitudinal ribs to form a plurality of water channels that may further include twisted strips providing a helical water flow pattern that increases turbulence within the water channels. The panel is connected to large pipes or headers on the top and bottom ends of the panel that receive the heated fluid from the water channels, allow the heated fluid to exit the panel, and for return water to re-enter the panel in a solar water heating system.

Systems and techniques for boltlessly supporting and securing solar modules are disclosed. For example, in an aspect, a system features a support structure including a support rail, and a frame including a plurality of rails each having a slot to receive a solar module therein and a bottom plate to boltlessly couple to the top surface of the support rail via one or more boltless mounting components. A boltless mounting component may include a post operative to interlock with an insertion hole for securing the frame to the support structure. Moreover, a locking pin may be disposed through a pin hole on each of the top surface of the support rail and the bottom plate of the frame, where the locking pin advantageously maintains a predetermined alignment and advantageously provides a shared electrical ground connection between the support rail and the frame.

Systems and techniques for boltlessly supporting and securing solar modules are disclosed. For example, in an aspect, a system features a support structure including a support rail, and a frame including a plurality of rails each having a slot to receive a solar module therein and a bottom plate to boltlessly couple to the top surface of the support rail via one or more boltless mounting components. A boltless mounting component may include a post operative to interlock with an insertion hole for securing the frame to the support structure. Moreover, a locking pin may be disposed through a pin hole on each of the top surface of the support rail and the bottom plate of the frame, where the locking pin advantageously maintains a predetermined alignment and advantageously provides a shared electrical ground connection between the support rail and the frame.

A solar collector housing that is opened and closed without tools includes structure for accommodating temperature-related expansion and contraction of a polymer absorber housed within the collector. The housing includes a transparent cover, a frame for holding the transparent cover, and a base. The cover, frame and base collectively define a hollow interior within which the polymer absorber is positioned. A plurality of latches is secured to an exterior of the frame. The frame and base are pivotally connected to one another when the latches are open so that the collector housing can be opened. The housing cannot be opened when the latches are closed. A pair of variable gate closure components are positioned in slots formed in a second end of the collector and enable the polymer absorber to expand and contract without placing stress on the absorber tubes.

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.

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 frame for a liquid-throughflowable 3D fabric includes two first frame parts lying opposite each other, where each first frame part is configured to lie against at least a first part of a peripheral edge of the 3D fabric and to close the fabric at least substantially liquid-tightly along the first part of the peripheral edge. An assembly with such a frame and liquid-throughflowable 3D fabric, where the first parts of the peripheral edge of the 3D fabric are closed at least substantially liquid-tightly by the frame. A 3D fabric includes two main surfaces which are connected to each other along at least a part of the peripheral edge of the 3D fabric.

A frame for a liquid-throughflowable 3D fabric includes two first frame parts lying opposite each other, where each first frame part is configured to lie against at least a first part of a peripheral edge of the 3D fabric and to close the fabric at least substantially liquid-tightly along the first part of the peripheral edge. An assembly with such a frame and liquid-throughflowable 3D fabric, where the first parts of the peripheral edge of the 3D fabric are closed at least substantially liquid-tightly by the frame. A 3D fabric includes two main surfaces which are connected to each other along at least a part of the peripheral edge of the 3D fabric.

A solar water pasteurizer has a water jug removably disposed in a solar box with insulation and a solar window. The water jug has a lid to close an aperture in the solar box and a handle thermally isolated from the water jug to facilitate handling of the water jug with heated water. Multiple water jugs can be swapped in and out of the solar box. The solar box also has a thermal mass to preserve some heat in the solar box.