Solar heat collection

Apparatus for collecting solar heat comprising a substantially planar radiation receptor adapted to be supported at an inclination across the path of sunlight, said receptor being composed essentially of thin sheet material and comprising a thin front panel exposed to the solar radiation, a back panel and means interconnecting said panels peripherally and in and along laterally spaced longitudinal regions thereof so as to define between them a shallow fluid-tight chamber subdivided into a multiplicity of long shallow channels for confining liquid filling them to a thin layer and extending from a common plenum space in the lower end of the chamber to a common plenum space in its upper end, an inlet to said lower plenum space for liquid flow thereinto, an outlet from said upper plenum space for outflow of liquid, said channels each being of not more than 1/2 inch in average depth and being sufficiently limited in width so that liquid filling and being heated in said channels will not distort them and will flow only upwardly in them under the influence of thermal-specific gravity gradients to bring hotter liquid preferentially into said upper plenum space, conduit means for conducting liquid in a circuit from said outlet to a heat exchange zone and thence back into said inlet, means for keeping said receptor and said conduit means completely filled with liquid and holding the liquid in said receptor constantly under a substantially uniform limited hydrostatic pressure insufficient to rupture said receptor, and means for continuously circulating the liquid in said circuit into and upwardly through and from said receptor under a constantly low pumping pressure sufficient to prevent substantial deviation from said hydrostatic pressure as said liquid is being circulated,

• said heat exchange zone comprising a liquid-to-liquid heat exchanger having therein passageway connected in said circuit with said conduit means for conducting said liquid along one side of heat transfer walls adapted to be contacted over their other side by a second liquid to be heated, said liquid circulating means including a pump in said conduit means, a tank for storing said second liquid in heated state, means for flowing said second liquid through said heat exchanger in contact with said other side of said walls and thence into said tank, a first means for sensing the temperature of liquid in said upper plenum space, means activated by said first means for operating said pump when said temperature exceeds a first predetermined level, a second means for sensing the temperature of liquid being pumped through said circuit, and means activated by said second means for operating said means for flowing said second liquid when the latter temperature exceeds a second predetermined level higher than said first temperature level.

Apparatus for collecting solar heat comprising a substantially planar radiation receptor adapted to be supported at an inclination across the path of sunlight, said receptor being composed essentially of thin sheet material and comprising a thin front panel exposed to the solar radiation, a back panel and means interconnecting said panels peripherally and in and along laterally spaced longitudinal regions thereof so as to form them into and define between them a shallow fluid-tight chamber subdivided into a multiplicity of long shallow channels for confining liquid filling them to a thin layer and extending from a common plenum space in the lower end of the chamber to a common plenum space in its upper end, an inlet to said lower plenum space for liquid flow thereinto, an outlet from said upper plenum space for outflow of liquid, said channels each being of not more than one-half inch in average depth and being sufficiently limited in width so that liquid filling and being heated in said channels will not distort them and will flow only upwardly in them under the influence of thermal-specific gravity gradients to bring hotter liquid preferentially into said upper plenum space, conduit means for conducting liquid in a circuit from said outlet to a heat exchange zone and thence back into said inlet, means for keeping said receptor and said conduit means completely filled with liquid and holding the liquid in said receptor constantly under a substantially uniform limited hydrostatic pressure insufficient to rupture said receptor, and means for continuously circulating the liquid in said circuit into and upwardly through and from said receptor under a constantly low pumping pressure sufficient to prevent substantial deviation from said hydrostatic pressure as said liquid is being circulated,

• said apparatus further comprising closure means including a transparent cover sheet spaced from said front panel and forming over said receptor a substantially gas-tight cover space containing air or other radiation permeable gas, and means communicating with said cover space for flowing gas into and from the same in response to variations of the pressure therein, said means for flowing gas comprising a surge chamber holding gas in communication with the gas in said cover space.

Apparatus for collecting solar heat comprising a substantially planar radiation receptor adapted to be supported at an inclination across the path of sunlight, said receptor comprising a thin front panel exposed to the solar radiation, a back panel and means interconnecting said panels peripherally and in and along laterally spaced longitudinal regions thereof so as to define between them a shallow fluid-tight chamber subdivided into a multiplicity of long shallow channels for confining liquid filling them to a thin layer and extending from a common plenum space in the lower end of the chamber to a common plenum space in its upper end, an inlet to said lower plenum space for liquid flow thereinto, an outlet from said upper plenum space for outflow of heated liquid, conduit means for conducting liquid completely filling said chamber and said conduit means in a circuit from said outlet to a heat exchange zone and thence back into said inlet, means for holding said liquid constantly under an elevated pressure insufficient to rupture said chamber, closure means including a transparent cover sheet spaced from said front panel and forming over said receptor a substantially gas-tight cover space containing air or other radiation permeable gas, and means communicating with said cover space for flowing gas into and from the same in response to variations of the pressure therein, said means for flowing gas comprising a surge chamber holding gas in communication with the gas in said cover space.

Apparatus for collecting solar heat comprising a substantially planar radiation receptor adapted to be supported at an inclination across the path of sunlight, said receptor comprising a thin front panel exposed to the solar radiation, a back panel and means interconnecting said panels peripherally and along laterally spaced longitudinal regions thereof so as to define between them a shallow fluid-tight chamber subdivided into a multiplicity of laterally sepatate long shallow channels for confining liquid filling them to a thin layer and extending from a common plenum space in the lower end of the chamber to a common plenum space in its upper end, an inlet to the lower plenum space for liquid flow thereinto and an outlet from the upper plenum space for outflow of heated liquid, said channels each being of not more than about one-half inch in average depth and being sufficiently limited in width that liquid filling and being heated in said channels will not distort them and will flow upwardly in them by thermal-gravity effects to collect heat in said upper plenum space, and closure means for shielding said receptor from ambient atmospheric conditions, said closure means including a heat insulating support having a base underlying and an upright side wall extending peripherally about said receptor and a transparent cover sheet spaced from said front panel and forming over said receptor a substantially gas-tight cover space containing air or other radiation permeable gas, and means including a gas containing surge chamber communicating with said cover space for flowing gas into and from the same in response to variations of the pressure therein.

Apparatus for collecting solar heat comprising a substantially planar radiation receptor adapted to be supported at an inclination across the path of sunlight, said receptor comprising a thin front panel exposed to the solar radiation, a back panel and means interconnecting said panels peripherally and in and along laterally spaced longitudinal regions thereof so as to define between them a shallow fluid-tight chamber subdivided into a multiplicity of laterally separate long shallow channels confining liquid filling them to a thin layer and extending from a common plenum space in the lower end of said chamber to a common plenum space in its upper end, an inlet to said lower plenum space for liquid flow thereinto, an outlet from said upper plenum space for outflow of heated liquid, conduit means for conducting liquid completely filling said chamber and said conduit means in a circuit from said outlet to a heat exchange zone and thence back into said inlet, means including a surge chamber vented to the atmosphere and holding liquid in communication with but at an elevation a short distance higher than the liquid in said circuit for holding said liquid constantly under an elevated pressure insufficient to rupture said chamber;

• said channels each being of not more than about one-half inch in average depth and being sufficiently limited in width that liquid filling and being heated in said channels will not distort them and will flow upwardly in them by thermal-gravity effects to collect heat in said upper plenum space, said chamber and said circuit having a liquid containing capacity amounting to less than 21/2 quarts per square foot of exposed front surface of said receptor;
• said heat exchange zone comprising a heat exchanger having therein passageway for conducting said liquid along one side of heat transfer walls adapted to be contacted over their other side by a fluid to be heated, a pump in said conduit means for flowing the liquid filling said circuit upwardly through said receptor chamber and thence back into said lower plenum space via said heat exchanger, means for sensing the temperature of liquid in said upper plenum space, and means activated by said sensing means for operating said pump when said temperature exceeds a predetermined level;
• a heat insulating support having a base underlying and an upright side wall extending peripherally about said receptor, closure means including a transparent cover sheet spaced from said front panel and forming over said receptor a substantially gas-tight cover space containing air or other radiation permeable gas, means including a gas containing surge chamber communicating with said cover space for flowing gas into and from the same in response to variations of the pressure therein, and means including a container holding a desiccant in the path of gas flow between said cover space and said surge chamber for removing moisture from said gas flow.