Abstract: A solar-energy collector has an absorber (5, 31) located in the bottom of a box-like casing, which includes a cover plate (1) which is permeable to solar radiation. The casing encloses a dry gas, to thereby avoid condensation in the solar-energy collector. The casing is hermetically sealed and contains a constant quantity of gas. The cover plate is movably suspended in a resilient frame (2, 20) which forms part of the casing and which permits movement of the cover plate in a direction perpendicular to the plane thereof in response to changes in gas temperature. This enables harmful pressure variations to be avoided in the collector, and the cover plate rests, well protected, on an elastically resilient cushion of gas.

Abstract: A solar-energy collector having an absorber unit comprising two plates (1, 2) of rigid material, having an intermediate space for a flowing medium to be heated. In order to obtain a form-stable unit having temperature equilizing properties, the two plates (1, 2) are wave-shaped (3, 4) in mutually intersecting directions, symmetrically in relation to the main direction of flow of the medium, and the plates abut each other at the points of intersection, at which points the plates are joined together by welding, adhesive bonding or the like.