Abstract: A solar collector comprises a solar radiation absorbing surface, a transparent cover over but spaced from the absorbing surface, and a convection and heat radiation suppressing structure occupying at least part of the space between the absorbing surface and the transparent cover. The convection and heat radiating suppressing structure includes a self-supporting structure comprising at least two thin, corrugated transparent foils placed on top of each other in contiguous relationship such that they form a system of long narrow ducts between adjacent foils, the ducts extending substantially parallel to the absorbing surface. Provision is made for providing heat carrying fluid within the space between the absorbing structure, and the cover, including within the ducts between the foils.