Sheet-flow concrete solar collector

A sheet-flow type solar collector, comprising a reinforced concrete slab acting as a backing insulation and having an upper surface acting as a photothermal conversion surface, the photothermal conversion surface being coated with an impermeable cermet coating having high absorptivity to light radiation and low emissivity for thermal radiation, said coating further having an exposed surface of high capillarity, with fluid-conducting channels in said upper surface with ridges between the channels, an inner glazing substantially in contact with the ridges, an outer glazing spaced from the inner glazing, means retaining the two glazings to the slab, the inner glazing serving to contain the flow of a heat transfer fluid along the conversion surface and the outer glazing serving to reduce convection and radiation heat losses, and means for admitting the heat transfer fluid to flow longitudinally over the conversion surface, in the fluid-conducting channels, and means for collecting heated transfer fluid from the conversion surface, the concrete slab being at least about two inches thick and of good insulation properties, cast with formed voids spaced closely to the conversion surface, said means for admitting fluid including an input header at the upper, upstream end of the slab, comprising a trough extending laterally through substantially the width of the photothermal conversion surface, formed in the slab's surface and having a gentle downstream slope in the installed, inclined configuration of the collector, leading to the upstream end of the conversion surface, and including a cover plate over the trough and extending to the photothermal conversion surface, providing an exit for heat transfer fluid from the trough to the conversion surface.

A sheet-flow type solar collector, comprising a reinforced concrete slab acting as a backing insulation and having an upper surface acting as a photothermal conversion surface, the photothermal conversion surface being coated with an impermeable cermet coating having high absorptivity to light radiation and low emissivity for thermal radiation, said coating further having an exposed surface of high capillarity, with an inner glazing substantially in contact with the conversion surface, an outer glazing spaced from the inner glazing, and means retaining the two glazings to the slab, the inner glazing serving to contain the flow of a heat transfer fluid along the conversion surface and the outer glazing serving to reduce convection and radiation heat losses, the conversion surface including a series of parallel grooves from the upper end of the slab to the lower end, with ridges between the grooves and with the inner glazing resting substantially on the ridges, for containing the heat transfer fluid in the grooves and under the inner glazing, the grooves being of such cross-sectional area, for the inclination of the collector in a particular installation, as to accommodate about 13 to 16 pounds fluid per square foot of collector area per hour, means for admitting the heat transfer fluid to flow longitudinally over the conversion surface, and means for collecting heated transfer fluid from the conversion surface, the concrete slab being at least about two inches thick and of good insulation properties.

A sheet-flow type solar collector, comprising a reinforced concrete slab acting as a backing insulation and having an upper surface acting as a photothermal conversion surface, the photothermal conversion surface being coated with an impermeable cermet coating having high absorptivity to light radiation and low emissivity for thermal radiation, said coating further having an exposed surface of high capillarity, with an inner glazing substantially in contact with the conversion surface, an outer glazing spaced from the inner glazing, and means retaining the two glazings to the slab, the inner glazing serving to contain the flow of a heat transfer fluid along the conversion surface and the outer glazing serving to reduce convection and radiation heat losses, the conversion surface including a series of parallel grooves from the upper end of the slab to the lower end, with ridges between the grooves and with the inner glazing resting substantially on the ridges, for containing the heat transfer fluid in the grooves and under the inner glazing, the grooves being of such cross-sectional area, for the inclination of the collector in a particular installation, as to accommodate about 13 to 16 pounds fluid per square foot of collector area per hour, means for admitting the heat tranfer fluid to flow longitudinally over the conversion surface, including an input header at the upper, upstream end of the slab, comprising a trough extending laterally through substantially the width of the photothermal conversion surface, formed in the slab's surface and having a gentle downstream slope in the installed, inclined configuration of the collector, leading to the grooves generally at the level of their bottoms, and including a cover plate over the trough and extending to the photothermal conversion surface and substantially in contact with the upstream ends of the ridges between the grooves, forming heat transfer fluid passages at the upstream ends of the grooves, whereby heat transfer fluid pools behind the passages and is evenly distributed to the passages and the grooves, and means for collecting heated transfer fluid from the conversion surface, the concrete slab being at least about two inches thick and of good insulation properties.

A sheet-flow type solar collector, comprising a reinforced concrete slab acting as a backing insulation and having an upper surface acting as a photothermal conversion surface, the photothermal surface being coated with an impermeable polymeric coating having high absorptivity to light radiation and low emissivity for thermal radiation, said coating further having an exposed surface of high capillarity, with fluid-conducting channels in said upper surface with ridges between the channels, an inner glazing substantially in contact with the ridges, an outer glazing spaced from the inner glazing, means retaining the two glazings to the slab, the inner glazing serving to contain the flow of a heat transfer fluid along the conversion surface and the outer glazing serving to reduce convection and radiation heat losses, and means for admitting the heat transfer fluid to flow longitudinally over the conversion surface, in the fluid-conducting channels, and means for collecting heated transfer fluid from the conversion surface, the concrete slab being at least about two inches thick and of good insulation properties, cast with formed voids spaced closely to the conversion surface, said means for admitting fluid including an input header at the upper, upstream end of the slab, comprising a trough extending laterally through substantially the width of the photothermal conversion surface, formed in the slab's surface and having a gentle downstream slope in the installed, inclined configuration of the collector, leading to the upstream end of the conversion surface, and including a cover plate over the trough and extending to the photothermal conversion surface, providing an exit for heat transfer fluid from the trough to the conversion surface.

A sheet-flow type solar collector, comprising a reinforced concrete slab acting as a backing insulation and having an upper surface acting as a photothermal conversion surface, the photothermal conversion surface being coated with an impermeable polymeric coating having high absorptivity to light radiation and low emissivity for thermal radiation, said coating further having an exposed surface of high capillarity, with an inner glazing substantially in contact with the conversion surface, an outer glazing spaced from the inner glazing, and means retaining the two glazings to the slab, the inner glazing serving to contain the flow of a heat transfer fluid along the conversion surface and the outer glazing serving to reduce convection and radiation heat losses, the conversion surface including a series of parallel grooves from the upper end of the slab to the lower end, with ridges between the grooves and with the inner glazing resting substantially on the ridges, for containing the heat transfer fluid in the grooves and under the inner glazing, the grooves being of such cross-sectional area, for the inclination of the collector in a particular installation, as to accommodate about 13 to 16 pounds fluid per square foot of collector area per hour, means for admitting the heat transfer fluid to flow longitudinally over the conversion surface, and means for collecting heated transfer fluid from the conversion surface, and means for collecting heated transfer fluid from the conversion surface, the concrete slab being at least about two inches thick and of good insulation properties.

A sheet-flow type solar collector, comprising a reinforced concrete slab acting as a backing insulation and having an upper surface acting as a photothermal conversion surface, the photothermal conversion surface being coated with an impermeable polymeric coating having high absorptivity to light radiation and low emissivity for thermal radiation, said coating further having an exposed surface of high capillarity, with an inner glazing substantially in contact with the conversion surface, an outer glazing spaced from the inner glazing, and means retaining the two glazings to the slab, the inner glazing serving to contain the flow of a heat transfer fluid along the conversion surface and the outer glazing serving to reduce convection and radiation heat losses, the conversion surface including a series of parallel grooves from the upper end of the slab to the lower end, with ridges between the grooves and with the inner glazing resting substantially on the ridges, for containing the heat transfer fluid in the grooves and under the inner glazing, the grooves being of such cross-sectional area, for the inclination of the collector in a particular installation, as to accommodate about 13 to 16 pounds fluid per square foot of collector area per hour, means for admitting the heat transfer fluid to flow longitudinally over the conversion surface, including an input header at the upper, upstream end of the slab, comprising a trough extending laterally through substantially the width of the photothermal conversion surface, formed in the slab's surface and having a gentle downstream slope in the installed, inclined configuration of the collector, leading to the grooves generally at the level of their bottoms, and including a cover plate over the trough and extending to the photothermal conversion surface and substantially in contact with the upstream ends of the ridges between the grooves, forming heat transfer fluid passages at the upstream ends of the grooves, whereby heat transfer fluid pools behind the passages and is evenly distributed to the passages and the grooves, and means for collecting heated transfer fluid from the conversion surface, the concrete slab being at least about two inches thick and of good insulation properties.

A sheet-flow type solar collector system comprising a reinforced concrete slab acting as a backing insulation and having an upper surface acting as a photothermal conversion surface, including fluid-conducting channels in the upper surface with ridges between the channels, an inner glazing substantially in contact with the ridges, an outer glazing spaced from the inner glazing, means retaining the two glazings to the slab, the inner glazing serving to contain the flow of a heat transfer fluid along the conversion surface and the outer glazing serving to reduce convection and radiation heat losses, and means for admitting the heat transfer fluid to flow longitudinally over the conversion surface, in the fluid-conducting channels, and means for collecting heated transfer fluid from the conversion surface, the concrete slab being at least about two inches thick and of good insulation properties, cast with formed voids spaced closely to the conversion surface, said means for admitting fluid including an input header at the upper, upstream end of the slab, comprising a trough extending laterally through substantially the width of the photothermal conversion surface, formed in the slab's surface and having a gentle downstream slope in the installed, inclined configuration of the collector, leading to the upstream end of the conversion surface, and including a cover plate over the trough and extending to the photothermal conversion surface, providing an exit for heat transfer fluid from the trough to the conversion surface, said solar collector system being in a closed loop arrangement with a liquid receiving chamber at the downstream end of the collector, connected to said means for collecting heated fluid, a heat exchanger, a pump and liquid conduits connecting them, the heat transfer fluid comprising distilled water containing an antistatic agent, for preventing build-up of deposits and the formation of stationary air bubbles, so that the entire conversion surface is flooded.

A sheet-flow type solar collector system comprising a reinforced concrete slab acting as a backing insulation and having an upper surface acting as a photothermal conversion surface, an inner glazing substantially in contact with the conversion surface, an outer glazing spaced from the inner glazing, means retaining the two glazings to the slab, the inner glazing serving to contain the flow of a heat transfer fluid along the conversion surface and the outer glazing serving to reduce convection and radiation heat losses, the conversion surface including a series of parallel grooves from the upper end of the slab to the lower end, with ridges between the grooves and with the inner glazing resting substantially on the ridges, for containing the heat transfer fluid in the grooves and under the inner glazing, the grooves being of such cross-sectional area, for the inclination of the collector in a particular installation, as to accommodate about 13 to 16 pounds fluid per square foot of collector area per hour, means for admitting the heat transfer fluid to flow longitudinally over the conversion surface, and means for collecting heated transfer fluid from the conversion surface, the concrete slab being at least about two inches thick and of good insulation properties, the solar collector system being in a closed loop arrangement with a liquid receiving chamber at the downstream end of the collector, a heat exchanger, a pump and liquid conduits connecting them, the heat transfer fluid comprising distilled water containing an antistatic agent, for preventing build-up of deposits and the formation of stationary air bubbles, so that the entire conversion surface is flooded.

A sheet-flow type solar collector system, comprising a reinforced concrete slab acting as a backing insulation and having an upper surface acting as a photothermal conversion surface, a rigid inner glazing substantially in contact with the conversion surface, an outer glazing spaced from the inner glazing, a frame supporting the outer glazing on its top surface and the inner glazing on its bottom surface, means for retaining the frame to the slab at the periphery of the conversion surface, the inner glazing serving to contain the flow of a heat transfer fluid along the conversion surface and the outer glazing serving to reduce convection and radiation heat losses, the conversion surface including a series of parallel grooves from the upper end of the slab to the lower end, with ridges between the grooves and with the inner glazing resting substantially on the ridges, for containing the heat transfer fluid in the grooves and under the inner glazing, the system being in a thermosiphoning closed loop arrangement including a heat exchanger at a higher level than the collector and conduit means for connecting the heat exchanger to the ends of the collector, said rigid inner glazing serving to hold fluid beneath it, the heat transfer fluid comprising distilled water containing an antistatic agent, and including means associated with the concrete slab for admitting the heat transfer fluid to flow longitudinally over the conversion surface, including an input header at the upper, upstream end of the slab, comprising a trough extending laterally through substantially the width of the photothermal conversion surface, formed in the slab's surface and having a gentle downstream slope in the installed, inclined configuration of the collector, leading to the grooves generally at the level of their bottoms, and including a cover plate over the trough and extending to the photothermal conversion surface and substantially in contact with the upstream ends of the ridges between the grooves, forming heat transfer fluid passages at the upstream ends of the grooves, whereby heat transfer fluid pools behind the passages and is evenly distributed to the passages and the grooves, and means for collecting heated transfer fluid from the conversion surface, connected to said connecting means, the concrete slab being at least about two inches thick and of good insulation properties.

A sheet-flow type solar collector, comprising a reinforced concrete slab acting as a backing insulation and having an upper surface acting as a photothermal conversion surface, the photothermal conversion surface being coated with an impermeable cermet coating having high absorptivity to light radiation and low emissivity for thermal radiation, said coating further having an exposed surface of high capillarity, with an inner glazing substantially in contact with the conversion surface, an outer glazing spaced from the inner glazing, a frame supporting the outer glazing on its top surface and the inner glazing on its bottom surface, means for retaining the frame to the slab at the periphery of the conversion surface, the inner glazing serving to contain the flow of a heat transfer fluid along the conversion surface and the outer glazing serving to reduce convection and radiation heat losses, the conversion surface including a series of parallel grooves from the upper end of the slab to the lower end, with ridges between the grooves and with the inner glazing resting substantially on the ridges, for containing the heat transfer fluid in the grooves and under the inner glazing, means for admitting the heat transfer fluid to flow longitudinally over the conversion surface, the means for admitting fluid including an input header at the upper, upstream end of the slab, comprising a trough extending laterally through substantially the width of the photothermal conversion surface, formed in the slab's surface and having a gentle downstream slope in the installed, inclined configuration of the collector, leading to the grooves generally at the level of their bottoms, and including a cover plate over the trough and extending to the photothermal conversion surface and substantially in contact with the upstream ends of the ridges between the grooves, forming heat transfer fluid passages at the upstream ends of the grooves, whereby heat transfer fluid pools behind the passages and is evenly distributed to the passages and the grooves, and means for collecting heated transfer fluid from the conversion surface, the concrete slab being at least about two inches thick and of good insulation properties.

A sheet-flow type solar collector, comprising a reinforced concrete slab acting as a backing insulation and having an upper surface acting as a photothermal conversion surface, the photothermal conversion surface being coated with an impermeable polymeric coating having high absorptivity to light radiation and low emissivity for thermal radiation, said coating further having an exposed surface of high capillarity, with an inner glazing substantially in contact with the conversion surface, an outer glazing spaced from the inner glazing, a frame supporting the outer glazing on its top surface and the inner glazing on its bottom surface, means for retaining the frame to the slab at the periphery of the conversion surface, the inner glazing serving to contain the flow of a heat transfer fluid along the conversion surface and the outer glazing serving to reduce convection and radiation heat losses, the conversion surface including a series of parallel grooves from the upper end of the slab to the lower end, with ridges between the grooves and with the inner glazing resting substantially on the ridges, for containing the heat transfer fluid in the grooves and under the inner glazing, means for admitting the heat transfer fluid to flow longitudinally over the conversion surface, the means for admitting fluid including an input header at the upper, upstream end of the slab, comprising a trough extending laterally through substantially the width of the photothermal conversion surface, formed in the slab's surface and having a gentle downstream slope in the installed, inclined configuration of the collector, leading to the grooves generally at the level of their bottoms, and including a cover plate over the trough and extending to the photothermal conversion surface and substantially in contact with the upstream ends of the ridges between the grooves, forming heat transfer fluid passages at the upstream ends of the grooves, whereby heat transfer fluid pools behind the passages and is evenly distributed to the passages and the grooves, and means for collecting heated transfer fluid from the conversion surface, the concrete slab being at least about two inches thick and of good insulation properties.