TECHNOLOGY FOCUS - MECHANICAL ENGINEERING - Preferred Components: The clamping element of second type and the supplementary panel can be held in the operative position by a second clamping element (19b). The clamping elements of first and second types are shaped like an upside down U, or rider. The supplementary panel is associated with the outer surface of the panel. The circulation mechanism comprises hydraulic circuits; a pipe (17) with circular, oval, polygonal, or rectangular section; or a cavity obtained by shaping a sheet panel and made watertight by welding. The pipe is attached to the panel. It is made of metal sheet or plate with various finishes or surface treatments and/or other material which is suitable for the specific use of constructing the panel. A heat-insulating layer (24) is associated with the inner surface of the panel. Photovoltaic cells are inserted or integrated in the supplementary panel. Guide profiles are inserted between two adjacent panels or in an intermediate position of the two adjacent panels. A spacer element of elastic material is inserted between two attachment mechanisms to support heat dilations of the supplementary panels. Two of the adjacent attachment mechanisms are positioned with a certain play inside the relative guide profile. Each attachment mechanism has a length less than the inter-axis with which the supplementary panels are attached. An end attachment mechanism is arranged in a fixed manner to function as a positioning abutment. The attachment mechanism and clamping elements are attached to each other by another attachment element. The attachment mechanisms comprise longitudinal slits, and elements for electric conduction. The attachment mechanisms and clamping elements are made of thermally and electrically insulating material resistant to high/low temperature. The thermal carrier fluid is sent to the circulation mechanism by delivery collector and discharged from the circulation mechanism by return collector. The delivery and return collectors are positioned at a distance from each other on the covering of the pitch of the roof or wall. The delivery and return collectors are both positioned in a dome at the upper end of the pitch of a covering of the roof.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The attachment mechanisms are made of heterogeneous rigid-elastic material, or compact material such as wood or polyvinyl chloride.