Solar collector, comprising an evaporation/condensation system

Claim 1

A solar collector, which comprises a sealed tube having an evaporation zone receiving solar energy during operation and a condensation zone arranged during operation at a level higher than that of the evaporation zone; an evaporable heat transport medium contained in said tube, said heat transport medium during operation being evaporated in the evaporation zone and being condensed in the condensation zone, the resulting condensate returning to the lower end of the evaporation zone under the influence of gravity; a plurality of pieces of a liquid-absorbing material arranged within the evaporation zone of the tube in contact with the inner surface thereof and extending in a row longitudinally of said tube, adjacent liquid-absorbing material pieces being spaced from each other, said spaced liquid-absorbing material pieces each respectively retaining a portion of the returning condensate and thereby interrupting the return of all the condensate to the lower end of the evaporation zone whereby, upon start of operation, evaporation of the heat transport medium occurs also along the length of the evaporation zone rather than solely at the lower end of said evaporation zone; and a shaft for mounting said pieces to maintain the same in contact with the inner surface of the evaporation zone of the tube in which the shaft is freely rotatable about the tube axis.