An invention proposes a solar radiation absorbing panel that serves preferably for air heating,

The solar radiation absorbing panel is constructed from two metal sheets.

The metal sheets are sealingly joined along their edges.

The metal sheets are provided with mechanical or magnetic means; the both metal sheets are interlocked by these means along some lines or at some spots.

This ensures diminishment of buckling these sheets under operating pressure and establishing of a certain distance between them with small deviations with respect to its average value.

The outer side of one metal sheet is coated with a black or selective paint absorbing solar radiation.

A device is describe for collecting energy in electromagnetic radiation, where the device includes a first panel that includes a first height, a first end, and a second end such that a first length is defined between the first end and the second end. The device further includes a second panel that includes a second height, a third end, and a fourth end such that a second length is defined between the third end and the fourth end. In addition, the first height and the second height are substantially parallel to a reference axis, the first end and the third end intersect to form a leading edge that is substantially parallel to the reference axis, and the first panel and the second panel form a channel positioned between the first panel and the second panel. Further, the channel is configured for the flow of a first heat-transfer medium through the channel, and at least a part of the first panel and at least a part of the second panel are configured to absorb electromagnetic radiation to transfer energy from the electromagnetic radiation to the first heat-transfer medium.

A device is provided for the air-based solar thermal generation of process heat in order to assist in drying processes. The device may add the solar-thermally generated hot air as a function of the relative temperature of the solar-thermally generated hot air as a partial flow of the process air generated by other systems.