초록 ▼

A solar energy collector element having an inner tube which carries a heat exchange fluid, an outer glass tube, an evacuated space between the two tubes and a solar selective surface coating in thermal contact with the outer surface of the inner tube. A gas is admitted to the evacuated space for the

A solar energy collector element having an inner tube which carries a heat exchange fluid, an outer glass tube, an evacuated space between the two tubes and a solar selective surface coating in thermal contact with the outer surface of the inner tube. A gas is admitted to the evacuated space for the purpose of degrading the vacuum and limiting the stagnation temperature of the collector element. The gas is selected to exhibit hydrophobic characteristics, to absorb onto the selective surface coating at temperatures less than a predetermined temperature to desorb into the evacuated space at temperatures greater than the predetermined temperature but not adsorb significantly onto the outer glass tube.

대표청구항 ▼

A collector element for use in a solar energy collector system, said element comprising an inner tube which in use carries a heat exchange fluid, an outer glass tube which envelopes at least a portion of the length of the inner tube, an evacuated space located between and defined by the outer surfac

A collector element for use in a solar energy collector system, said element comprising an inner tube which in use carries a heat exchange fluid, an outer glass tube which envelopes at least a portion of the length of the inner tube, an evacuated space located between and defined by the outer surface of the inner tube and the inner surface of the outer tube, a solar selective surface coating in thermal contact with the outer surface of the inner tube, and a gas which is admitted into the evacuated space for the purpose of limiting the stagnation temperature of the collector element; the solar selective surface coating comprising a metal-carbide cermet on a metal base, the meal-carbide being graded from a metal rich layer at the coating-base interface to a carbon rich layer at its outer surface, the gas being selected to adsorb onto the solar selective surface coating at temperatures less than a predetermined temperature and to desorb into the evacuated space at temperatures greater than the predetermined temperature, and the gas being hydrophobic whereby it exhibits a significantly greater adsorption affinity to the solar selective surface coating than to the inner surface of the outer glass tube.