The invention relates generally to the collection of solar energy to provide electric power or electric power and heat.
Alternate sources of energy are needed to satisfy ever increasing world-wide energy demands. Solar energy resources are sufficient in many geographical regions to satisfy such demands, in part, by provision of electric power and useful heat.
Systems, methods, and apparatus by which solar energy may be collected to provide electricity or a combination of heat and electricity are disclosed herein.
In one aspect, a solar energy receiver comprises a linearly extending substrate comprising two or more coolant channels extending through the substrate along its long axis, and solar cells in thermal contact with the substrate. The substrate is formed by an extrusion process from, for example, aluminum or an aluminum alloy. The coolant channels may have, for example, substantially rectangular cross sections perpendicular to the long axis of the substrate. The solar cells may be included, for example, in a stack of two or more laminated layers disposed on the substrate.
In another aspect, a solar energy receiver comprises a substrate having a front surface, a back surface opposite to the front surface, and side surfaces, and a plurality of solar cells disposed in a stack of laminated layers on the front surface of the substrate. The solar receiver also comprises one or more electrical components disposed on the back surface of the substrate, and an electrically insulated interconnect passing from the front surface of the substrate, around a side surface of the substrate, to the back surface of the substrate to electrically interconnect one or more of the solar cells to one or more of the electrical components. The solar energy receiver may further comprise a solar radiation shield positioned to protect the electrical components from illumination by solar radiation, and/or a solar radiation shield positioned to protect the electrically insulated interconnect from illumination by solar radiation.
In some variations of this aspect, the electrically insulated interconnect comprises a laminated structure including one or more electrical conductors laminated between two or more electrically insulating layers. In some such variations, at least an end portion of the laminated structure of the electrically insulated interconnect is included in the stack of laminated layers on the front surface of the substrate. The laminated structure of the electrically insulated interconnect may be protected by a shield from illumination by solar radiation.
In another aspect, a solar energy receiver comprises a linearly extending substrate comprising two or more coolant channels extending through the substrate along its long axis, solar cells in thermal contact with the substrate, and an end piece providing separate fluid flow paths to an end of each coolant channel and otherwise sealing an end of the substrate to coolant flow. The substrate may be sealed to coolant flow by, for example, a weld between the end piece and the substrate. The solar energy receiver may further comprise a coolant manifold that distributes coolant from an inlet of the manifold to the separate coolant flow paths in the end piece. A gasket may be located between the coolant manifold and the end piece to seal their interface. The gasket may comprise, for example, an orifice for each coolant channel in the substrate, with the orifices controlling coolant flow through corresponding coolant channels.
In another aspect, a solar energy receiver comprises a linearly extending substrate comprising two or more coolant channels extending through the substrate along its long axis, solar cells in thermal contact with the substrate, and an orifice for each coolant channel in the substrate, with each orifice providing a pressure drop during coolant flow greater than the pressure drop across its corresponding coolant channel. The orifices may be provided, for example, in a gasket otherwise sealing an end of the substrate to coolant flow.
In another aspect, a solar energy receiver comprises a substrate, a conversion coating on a surface of the substrate, and a plurality of solar cells disposed in a stack of laminated layers on the conversion coated surface of the substrate. The substrate may extend linearly and comprise two or more coolant channels extending through the substrate along its long axis. The substrate may be formed, for example, by an extrusion process.
In another aspect, a solar energy receiver comprises a linearly extending substrate having a front surface, a back surface, and side surfaces, with the side surfaces each comprising a slot running parallel to a long axis of the substrate along at least a portion of the substrate. The slots may have, for example, substantially t-shaped cross sections perpendicular to their long axes. The solar receiver further comprises solar cells disposed on the front surface of the substrate. The substrate may comprise two or more coolant channels extending through the substrate along its long axis. The substrate may be formed by an extrusion process.
In another aspect, a solar energy receiver comprises a plurality of solar cells electrically connected in series and a first plurality of bypass diodes. Each of the bypass diodes is connected between a conductor (i.e., the same conductor) and a different location in the series of solar cells. The solar energy receiver may further comprise a second plurality of bypass diodes electrically connected in series with each other and, separately, in parallel with different ones or groups of the solar cells. The solar receiver may further comprise a linearly extending substrate on which the solar cells are disposed, with the first plurality of bypass diodes electrically connected to bypass solar cells located at an end portion of the substrate. The substrate may comprise, for example, two or more coolant channels extending through the substrate along its long axis.
In another aspect, a solar energy receiver comprises a linearly extending substrate comprising two or more coolant channels extending through the substrate along its long axis, solar cells in thermal contact with the substrate, and a compression plug at least partially inserted into and sealing an end of one of the coolant channels. The compression plug may comprise, for example, a plug portion, a gasket on the plug portion, and a wedge portion that may be drawn against the plug portion to press the gasket against an interior wall of a coolant channel to thereby seal the coolant channel.
In another aspect, a solar energy receiver comprises a substrate having a front surface, a back surface opposite to the front surface, and side surfaces. A plurality of solar cells is disposed on the front surface of the substrate. The solar energy receiver also comprises an enclosure enclosing one or more electrical components electrically connected to one or more of the solar cells. A portion of the enclosure is shaped to define a slot dimensioned to fit around a portion of the front surface of the substrate, a side surface of the substrate, and a portion of the back surface of the substrate.
In another aspect, a solar energy receiver comprises a first linearly extending substrate having a substantially rectangular cross-section and comprising two or more coolant channels extending through the substrate along its long axis, a first plurality of solar cells disposed on a surface of the first substrate, a second linearly extending substrate having a substantially rectangular cross section and comprising two or more coolant channels extending through the substrate along its long axis, and a second plurality of solar cells disposed on a surface of the second substrate. The first substrate and the second substrate are mechanically coupled to each other to form a V-shape with a long axis of the first substrate parallel to a long axis of the second substrate and with the surfaces on which the solar cells are disposed facing outwards. The V-shape may make an interior angle of, for example, about 90 degrees.
The solar cells disposed on the first substrate may be electrically connected, for example, in series or in parallel with those on the second substrate. Coolant may flow, for example, in series or in parallel through the first and second substrates.
The solar energy receivers of the various aspects summarized above may provide, for example, an electrical output, a heat output (in the form of heated coolant, for example), or both an electrical and a heat output. The receivers may be illuminated by concentrated radiation, for example, in a trough, linear Fresnel, or any other suitable solar energy collection system.
These and other embodiments, features and advantages of the present invention will become more apparent to those skilled in the art when taken with reference to the following more detailed description of the invention in conjunction with the accompanying drawings that are first briefly described.
The following detailed description should be read with reference to the drawings, in which identical reference numbers refer to like elements throughout the different figures. The drawings, which are not necessarily to scale, depict selective embodiments and are not intended to limit the scope of the invention. The detailed description illustrates by way of example, not by way of limitation, the principles of the invention. This description will clearly enable one skilled in the art to make and use the invention, and describes several embodiments, adaptations, variations, alternatives and uses of the invention, including what is presently believed to be the best mode of carrying out the invention.
As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly indicates otherwise. Also, the term “parallel” is intended to mean “substantially parallel” and to encompass minor deviations from parallel geometries rather than to require that parallel rows of reflectors or solar cells, for example, or any other parallel arrangements described herein be exactly parallel.
This specification discloses apparatus, systems, and methods by which solar energy may be collected to provide electricity or a combination of electricity and heat. Examples of solar energy receivers are disclosed that may be used, for example, in trough or linear Fresnel solar energy collectors in which one or more mirrors concentrate solar radiation onto such a receiver. Solar (e.g., photovoltaic) cells in the receivers provide an electrical output. The solar cells may, in some variations, be actively cooled by a coolant that flows through the receiver. In some variations, heat collected by the coolant may also be made available for use as an energy source.
Receivers as disclosed herein may be used, for example, in some variations of the methods, apparatus, and systems disclosed in U.S. Provisional Patent Application Ser. No. 61/249,151, incorporated herein by reference in its entirety.
Referring now to
Although
T-slots 140 in the sides of substrate 130 are not required, and may be placed elsewhere or absent in some variations of receiver 100. For example, one or more t-slots similar or identical to t-slots 140 may be located on the back surface of substrate 130, and may run, for example parallel to the long axis of substrate 130. Such t-slots may run the full length of substrate 130 or, alternatively, only along one or more portions of substrate 130. In some variations in which the sides of substrate 130 are not (or not much) utilized for mechanical connections, lamination stack 120 may wrap around one or more sides of substrate 130 (e.g., one or both sides running parallel to the long axis) to reach and adhere to portions of the back side of substrate 130. Such wrapping of lamination stack 120 may run substantially the full length of substrate 130 or, alternatively, only along one or more portions of 130. In the latter case, portions of the sides of substrate 130 may remain available to be relatively easily utilized for mechanical connections.
Substrate 130 (and hence receiver 100) may have, for example, a length of about 100 centimeters (cm) to about 400 cm, about 150 cm to about 350 cm, or about 275 cm to about 320 cm, a width of about 15 cm to about 25 cm, about 19 cm to about 22 cm, or about 20 cm to about 21 cm, and a thickness of about 1 cm to about 3 cm or about 1 cm to about 2 cm. In one example, substrate 130 has a length of about 160 centimeters (cm), a width of about 19.6 cm to about 20.8 cm, and a thickness of about 1.30 cm. In another example, substrate 130 has a length of about 275 cm, a width of about 19.6 cm to about 20.8 cm, and a thickness of about 1.30 cm. In another example, substrate 130 has length of about 320 cm, a width of about 19.6 cm to about 20.8 cm, and a thickness of about 1.30 cm.
In some variations, substrate 130 (comprising, e.g., t-slots and coolant fluid channels) is formed by an (e.g., conventional) extrusion process from, for example, aluminum or an aluminum alloy. Any other suitable material may also be used. In one example, substrate 130 is formed by an extrusion process from a 6063 aluminum alloy having a T-6 temper. One of ordinary skill in the art will recognize that extruded materials may be distinguished from cast materials, for example, by physical properties such as, for example, porosity, ductility, and and/or permeability.
Solar cells 110 may be electrically connected in any suitable manner described herein or known to one of ordinary skill in the art. In some variations, all of solar cells 110 are electrically connected in series. In other variations, some of solar cells 110, or some groups of solar cells 110, are electrically connected in parallel. Diodes may be used to bypass solar cells, or groups of solar cells, that would otherwise limit the electrical current due, for example, to a fault in the cell or cells or to shadowing (or any other cause of uneven illumination) of the cell or cells.
Referring again to
If one or more solar cells in one of groups 200 (e.g., group 200-3) limits current through that group to below a threshold value, the corresponding diode (e.g., diode 195-3) will turn on. Current will consequently bypass the limiting solar cell group (e.g., 200-3), as well as all other solar cell groups (e.g., 200-1 and 200-2) located earlier in the circuit. This arrangement provides the flexibility of allowing either a single (e.g. 200-1) or multiple solar cell groups to be bypassed with only a single diode voltage drop. In contrast, to bypass both of groups 170-2 and 170-3 requires two diode drops (across diodes 180-1 and 180-2). If, for example, during the course of a day (or a season) the edge of a shadow walks along receiver 100 from solar cell group 200-1 toward group 200-N, as these groups progressively join the shaded region of the receiver their corresponding diodes will turn on to bypass all shaded solar cell groups at the cost of a single diode drop.
Groups 200 may include one or more solar cells, and may include equal or differing numbers of solar cells. Groups 200 may include, for example, about 2 solar cells, about 5 solar cells, about 10 solar cells, about 15 solar cells, or about 20 solar cells. Any suitable number of groups 200 may be used. Diodes 195 may be, for example, incorporated into the solar cell circuit during manufacture of the solar cells, or be incorporated into or otherwise attached to substrate 130. Any suitable mounting of diodes 195, described herein or known to one of ordinary skill in the art, may be used.
In some variations, a receiver 100 is oriented such that, over time (e.g., during the course of a day or a year), solar radiation concentrated onto the receiver by reflectors, for example, walks along and off the length of receiver 100 and hence leaves a progressively lengthening portion of one end of receiver 100 unilluminated. This can occur, for example, as the angle of the sun above the horizon varies during the course of a day or a year. In such variations, the receiver 100 may include, at and/or near the end portion of the receiver experiencing the varying illumination, solar cell groups and diodes arranged as or similarly to groups 200 and diodes 195 in
Any suitable diodes may be used for diodes 180 and diodes 195. In some variations, diodes 180 and/or diodes 195 may be Vishay diodes having part number G1756 or Motorola diodes having part number MR756.
As noted earlier with respect to
The adhesive layers adhere to adjacent surfaces to hold stack 120 together and to attach it to substrate 130. Electrically insulating layer 220 electrically isolates solar cells 110 from substrate 130. Front sheet 250 provides a flat surface and protects solar cells 110 from the ambient environment. The layers between substrate 130 and solar cells 110 also accommodate mismatches in thermal expansion between the solar cells and the substrate, and conduct heat from the solar cells to the substrate.
In some variations, the width (the dimension in the plane of substrate 130 perpendicular to the long axis of the substrate) of the solar cells is less than that of some or all other layers in stack 120. This provides gaps between the edges of the solar cells and the edges of stack 120 that deter migration of moisture from the ambient environment through the edges of stack 120 to the solar cells. In some variations, one or more such gaps have widths greater than about 5 mm, greater than about 8 mm, greater than about 12 mm, or greater than about 15 mm. In some variations, one or more such gaps have widths greater than or equal to about 12.7 mm. In some variations, the solar cells have widths approximately equal to that of the substrate, and other layers of stack 120 extend beyond an edge or edges of substrate 130 to accommodate a gap as described above. In some other variations, stack 120 has a width approximately equal to that of the substrate, and solar cells 110 have widths less than that of the substrate to accommodate a gap as described above.
In one variation, adhesive layer 210 has a thickness of about 200 microns (gm) to about 500 μm and is or includes an EVA (ethyl vinyl acetate) based adhesive such as, for example, 15420P/UF adhesive available from STR Inc.; electrically insulating layer 220 has a thickness of about 100 μm to about 150 μm and is or includes a PET (polyethylene terephthalate) such as, for example, Melinex 648 or Melinex 6430, available from Dupont Teijin Films; second adhesive layer 230 has a thickness of about 200 μm to about 500 μm and is or includes an EVA based adhesive such as, for example, 15420P/UF adhesive available from STR Inc; solar cells 110 have a thickness of about 180 μm to about 240 μm (e.g., 180±30 μm or 210±30 μm); third adhesive layer 240 has a thickness of about 200 μm to about 500 μm and is or includes an EVA based adhesive such as, for example, 15420P/UF adhesive available from STR Inc; and front sheet 250 has a thickness of about 50 μm to about 400 μm, or about 50 μm to about 125 μm, or about 100 μm to about 400 μm and is or includes an ETFE (ethylene-tetrafluoroethylene) fluoropolymer such as, for example, Tefzel® available from Dupont™.
In other variations stack 120 may include additional or fewer layers or may substitute different materials and/or thicknesses for one or more of the layers. For example, in some variations adhesive layer 210 and/or adhesive layer 230 may be or include a filled EVA adhesive. In some variations, insulating layer 220 is or includes a PET which is dyed, filled, or in some other manner colored white. In other variations, adhesive layer 210 is about 50 μm thick, and electrically insulating layer 220 is or includes a PFV (polyvinyl fluoride film) such as, for example, a Tedlar® PVF film available from Dupont™. In some variations front sheet 250 is or includes a PET (polyethylene terephthalate) such as, for example, Melinex 6430 available from Dupont Teijin Films, and has a thickness of about 50 μm to about 125 μm. In other variations, front sheet 250 is or includes a silicate (e.g., low iron) glass sheet, such as for example a sheet of Solar Diamant glass available from Saint Gobain Glass and having a thickness of about 2.5 mm to about 4 mm.
In some variations, solar cells 110 are surrounded by a suitable silicone gel, available for example from Dow Corning, that replaces layers 210, 220, 230, and 240, and front sheet 250 is or includes a low iron glass sheet. The silicone gel, or portions thereof, may be a filled silicone gel. The silicone gel may have a thickness, for example, of about 200 μm to about 1000 μm.
Tabbing and electrical interconnects (e.g., bus bar 175) associated with solar cells 110 may be formed, for example, from copper ribbon conventionally tinned with solder.
Filled EVA, PET, and silicone materials suitable for use in stack 120 may include materials filled, for example, with particles of MgO, Al2O3, ZnO, BN, and/or carbon, or a mixture of particles of any thereof.
In some variations, surfaces of substrate 130 to which stack 120 is to be attached are treated with a (e.g., chemical) conversion coating process to provide a conversion coating on substrate 130 to which a bottom layer of stack 120 will more strongly adhere and/or to improve corrosion resistance of substrate 130. Suitable conversion coating processes include, but are not limited to, conventional chromate, phosphate, and oxide conversion coating processes. In one variation, conversion coating is performed according to Mil Spec MIL-C-5541 class 1a. In other variations, surfaces of substrate 130 to which stack 120 is to be attached may be sand or bead blasted to promote adhesion.
In variations in which front sheet 250 is or includes an ETFE (ethylene-tetrafluoroethylene) fluoropolymer such as, for example, Tefzel®, the surface of front sheet 250 to be bonded to adhesive layer 240 may be pre-treated with a conventional corona etching process to promote adhesion.
Stack 120 may be formed, for example, by stacking the layers on substrate 130 in the order as described above and then heating them in a conventional thermal laminator apparatus. Other methods of forming stack 120 may also be used.
In some variations, the surface of substrate 130 to which solar cells 110 are attached is curved in the directions perpendicular to the long axis of receiver 100 so that the centerline of that surface running parallel to the long axis is higher than the outer portions of that surface. The surface may have a radius of curvature of, for example, about 5 meters to about 100 meters. In such variations, stack 120 (including solar cells 110) laminated to such a curved surface adopts a comparable curvature, which may reduce strain in solar cells 110 resulting from thermal expansion. Also, in some variations some or all of solar cells 110 are scored or scribed (e.g., using for example, laser scribing or mechanical scoring or scribing) on their unilluminated surface to guide cracking that might occur in solar cells 110 along directions that preserve electrical connections to cracked portions of the cells. For example, a solar cell may be scribed or scored in the direction parallel to the long axis of receiver 100, with a single scribed or scored line located between each pair of parallel tabs along the cell. Other suitable arrangements of scribing or scoring may also be used. Lasers suitable for scribing solar cells in this manner may include, for example, pulsed lasers lasing at 1064 nanometers. Suitable lasers may be available, for example, from ROFIN or from Epilog Laser.
In some variations, one or more wiring channels run within substrate 130 substantially parallel its long axis for the length of, or portions of the length of, receiver 100. The wiring channels comprise wires or other conductors electrically coupled to solar cells 110 by, for example, additional wires or conductors electrically connected to the solar cells (e.g., to bus bars in lamination stack 120 electrically connected to the solar cells) via holes passing from the wiring channel or channels through substrate 130 to the surface on which lamination stack 120 is disposed. In some variations, this arrangement allows electrical interconnection of two or more receivers through their ends via the wiring channel or channels. In some variations, bypass diodes electrically connected to the solar cells as described above, for example, are also located in the wiring channels. In other variations, such bypass diodes are located in other channels or cavities in substrate 130 and electrically connected by additional wires or conductors to the solar cells, or to conductors in the wiring channel, via additional holes in substrate 130.
In some other variations receiver 100 comprises electrically insulated interconnects (e.g., insulated wires or insulated conducting ribbons) that pass through holes in the substrate or wrap around one or more edges of the substrate to electrically connect solar cells on a front surface of the receiver to one or more junction/diode boxes (e.g., including bypass diodes and/or sockets as described above) on a rear surface of the receiver. Such electrically insulated interconnects may have a laminate structure, in some variations.
Referring now to
Interconnect 260 extends beyond the other layers of laminate structure interconnect 255 to allow interconnect 260 to be electrically connected at one end to solar cells 110 (e.g., via bus bar 175) and electrically connected at another end to, e.g., a junction/diode box. In the illustrated example, one end portion of interconnect 260 extending beyond the other layers of laminate structure interconnect 255 is sandwiched, with solar cells 110 and their associated electrical interconnects, between adhesive layers 230 and 240 of laminate stack 120. An end portion of laminate structure interconnect 255 from which interconnect 260 protrudes may also be sandwiched between layers 230 and 240 of laminate stack 120 so that layers of laminate stack 120 and layers in laminate structure 255 overlap by, for example, about 5 mm, about 8 mm, about 12 mm, about 15 mm, about 20 mm, about 25 mm, or greater than about 25 mm. In some variations, the overlap is about 21 mm.
In some variations, each of insulating layers 280 and 310 has a thickness of about 50 μm to about 400 μm, or about 50 μm to about 125 μm, or about 100 μm to about 400 μm and is or includes an ETFE fluoropolymer such as, for example, Tefzel®, available from Dupont™; each of adhesive layers 290 and 300 has a thickness of about 200 μm to about 500 μm and is or includes any of the adhesive materials disclosed above for use in laminate stack 120; and interconnect 260 is formed from a copper ribbon conventionally tinned with solder.
In some variations in which laminate structure interconnect 255 includes ETFE (e.g., Tefzel) outer layers, these layers may be pre-treated with a conventional corona etching process on both sides of both layers (e.g., sheets), prior to assembly of laminate structure 255, to promote adhesion to layers in laminate structure 255 and to layers in stack 120.
In other variations, laminate structure interconnect 255 may include additional or fewer layers or may substitute different materials and/or thicknesses for one or more of the layers. Although in the illustrated example laminate structure interconnect 255 includes only a single electrical interconnect 260, in other variations laminate structure interconnect 255 may include two, three, four, or more interconnects 260. Laminate structure interconnect 255 may include as many interconnects 260 as necessary, for example, to electrically connect solar cells 110 to junction boxes and/or bypass diodes in configurations as described herein or as known to one of ordinary skill in the art.
In some variations, laminate structure interconnect 255 is formed prior to laminate stack 120, for example, by stacking the constituent layers of laminate structure interconnect 255 in the order described above and then heating them in a conventional laminator apparatus. In some such variations, lamination (i.e., formation) of interconnect 255 occurs at temperatures no greater than about 100° C. End portions of the resulting laminate, including an end portion of interconnect 260, may then be interleaved with layers from which laminate stack 120 is to be formed, and the resulting stack then laminated as described above with respect to stack 120. In other variations, the constituent layers of laminate structure interconnect 255 are stacked in the illustrated order and interleaved with the constituent layers of stack 120, also in the illustrated order, and then the resulting stack is laminated as above with respect to stack 120.
Referring now to
Receiver 100 is described in this specification as having an illuminated front side and an unilluminated rear or back side. It should be understood that these characterizations are meant to indicate that concentrated solar radiation may be intentionally directed to the (illuminated) front side, but not intentionally directed to the (unilluminated) back or rear side. Nevertheless, the back or rear side of receiver 100 may be illuminated by direct (not concentrated) solar radiation, and may be inadvertently illuminated by concentrated solar radiation. Laminate structure interconnect 255, described above, may also be exposed to direct solar radiation and/or inadvertently illuminated by concentrated solar radiation.
Referring now to
Shields 320 and 330 may be formed, for example, from sheet metal, metal foil, adhesive metal foil, metal tape, or from a metalized plastic and may be attached to receiver 100 with, for example, any suitable adhesive (e.g., Dow Corning® PV804), tape (e.g., 3M™ VHB™ tape), or mechanical fastener. The metal in such metal sheets, foils, tapes, or metalized plastics may be or comprise, for example, aluminum (anodized, or not) or steel. Junction/diode box shield 320 may have the form of a box, for example. Interconnect shield 330 may have, for example, an approximately “L” shape, with the long portion on the rear surface of receiver 100 and the short portion wrapping around a side of receiver 100. Shields 320 and 330 may be configured to maintain a small gap of about 1.5 mm between the shield and the shielded component (e.g., junction/diode box or interconnect) to prevent a shield heated by (e.g., concentrated) solar radiation from damaging the shielded component. In other variations, a heat conducting adhesive (e.g., PV804) may be used to couple the shield, the shielded component, and cooled substrate 130 in order to prevent such damage.
Referring now to
Referring now to
As noted above with reference to
The number and arrangement of the coolant channels may be selected, for example, to maintain temperature uniformity among solar cells 110 in directions transverse to the long axis of receiver 100, to minimize a change in temperature of solar cells 110 between opposite ends of receiver 100 along its long axis, to reduce a pressure drop for coolant flow between an inlet to and an outlet from the receiver, and/or to maintain support for front and back surfaces of substrate 130 (e.g., with ribs 137 shown in
In some variations, substrate 130 comprises one, two, three, four, five, or more than five coolant channels running the length of substrate 130 parallel to its long axis. The channels may have, for example, approximately rectangular, approximately elliptical, or approximately circular cross sections, or any other suitably shaped cross section. Substrates comprising such combinations of number and shape of coolant channel may be formed, for example, from aluminum, aluminum alloys, or other suitable material by, for example, an extrusion process. In some variations, substrate 130 comprises three channels of approximately rectangular cross section having cross-sectional dimensions of about 55 mm by about 7.5 mm.
Flow of coolant through channels in substrate 130 may be controlled, in some variations, by orifices. In some variations, receiver 100 comprises a separate orifice ahead of (in the coolant flow path) and in series with each coolant channel. The orifices may be connected in parallel to a single coolant feed tube or conduit, for example. Such orifices may have, for example, a diameter (or largest dimension) of about 3 mm to about 8 mm. In some variations, the orifices have circular cross sections with diameters of about 4.7 mm. The ratio of the hydraulic diameter (4·cross-sectional area/cross-sectional perimeter) of a coolant channel to that of an orifice ahead of and in series with the channel in the coolant flow path may be, for example, about 2 to about 3, or greater than about 3. In some variations, the ratio is about 2.8. A pressure drop across each orifice during operation may be, for example, about 2 times greater than, or more than about 2 times greater than, a pressure drop across its corresponding coolant channel. In some variations, a pressure drop across each orifice during operation may be, for example, about five times greater than a pressure drop across its corresponding coolant channel.
The orifices may be provided, for example, as orifices all in a single gasket in a seal at a coolant input end of substrate 130, as orifices in two or more gaskets (e.g., a separate gasket for each orifice) in one or more seals at a coolant input end of substrate 130, as orifices in one or more plugs at a coolant input end of substrate 130, or in any other suitable manner described herein or known to one of ordinary skill in the art.
Coolant may be delivered to the coolant channels, through orifices where used, by separate coolant feed tubes or conduits for each channel. Alternatively, coolant may be delivered by one or more coolant feed tubes or conduits to one or more coolant manifolds which distribute the coolant to the individual coolant channels.
Referring now to
Referring now to
Manifold 150 may be machined or cast, for example, and may be formed, for example, from aluminum, aluminum alloys, PPO, fluoropolymers (e.g., Teflon®), silicone, zinc, or any other suitable material. Though manifold 150 in the illustrated example is attached to end cap 145 with threaded fasteners, any other suitable method of attachment described herein or known to one of ordinary skill in the art may be used. Manifold 150 may be attached to end cap 145 by welding, brazing, or gluing, for example. Gasket 420 may be formed, for example, from a silicone or a fluoropolymer elastomer (e.g., Viton®) by a die-cutting process, for example. Feed tube 155 may be, for example, a 0.25 inch diameter tube, a 0.375 inch diameter tube, or any other suitable diameter tube and may be formed from aluminum, copper, plastic (e.g., cross-linked polyethylene (PEX)), or any other suitable material. Plastic tubing used for feed tube 155 may be optionally wrapped in silicone or aluminum foil. Fittings 445 may be, for example, conventional pipe fittings of suitable size for the tube.
Although the example of
Although the discussion above has been with respect to the flow of coolant into and through receiver 100, the same or similar types of assemblies (e.g., comprising an end cap, a fluid manifold, and a fluid interconnect) may be used as a coolant outlet from receiver 100. The outlet coolant flow path need not include any flow controlling orifice or orifices inducing a large pressure drop, however. In some variations, coolant is output from receiver 100 through an assembly essentially identical to an assembly through which coolant is input to receiver 100, apart from the absence of any flow control orifice in the outlet inducing a large pressure drop.
In some variations, the entire coolant fluid flow path through receiver 100 is formed from a same material such as, for example, aluminum or an aluminum alloy.
As noted above, two or more receivers 100 may be positioned, e.g., end-to-end and interconnected to form a larger receiver. Referring now to
Some variations do not utilize a fluid manifold to distribute coolant from an inlet to multiple coolant channels in substrate 130, but instead use multiple inlets each delivering coolant directly to corresponding individual channels in substrate 130. Referring to
Other methods for sealing or plugging ends of coolant channels in substrate 130 may also be used. Ends of coolant channels may be sealed, for example, with tapered plugs formed from compliant materials (e.g., plastics or epoxies) into shapes that conform with and may be introduced (e.g., wedged) into the ends of the channels to form a seal, or with plugs that may introduced into the channels to form gasket or o-ring seals. In variations in which the ends of coolant channels in substrate 130 are sealed with plugs that do not provide for introducing coolant into the channels through the plugs, coolant may be introduced into the coolant channels, for example, through interconnects fluidly coupled to the coolant channels through (e.g., tube fittings in or a fluid manifold on) the rear (unilluminated) surface of the substrate. Such interconnects, tube fittings, and fluid manifolds may be similar to, and be positioned similarly to, those described above.
Referring now to
In some variations two receivers 100 may be arranged and mechanically connected to form a V shape. Such a V-shape arrangement may provide additional stiffness, and may also position receivers 100 to be more effectively illuminated by concentrated solar radiation. In the example of
The solar cells disposed on the first substrate may be electrically connected, for example, in series or in parallel with those on the second substrate. Coolant may flow, for example, in series or in parallel through the first and second substrates. Hence, coolant may be input to and output from the V-shaped assembly of receivers at the same end (series flow) or at opposite ends (parallel flow).
Although
Referring now to
Torque tube 650 is pivotably attached to support posts 670a-670c, allowing reflectors 630a and 630b to rotate together with receivers 100a and 100b around pivot axis 680 to orient reflectors 630a and 630b to reflect solar radiation from the sun to, respectively, receivers 100a and 100b.
Reflectors 630a and 630b each comprise a plurality of linearly extending flat mirrors 690 supported by ribs 640a-640f to approximate a parabolic curvature. The aspect ratio (length divided by width) of flat mirrors 690 in the surface of reflectors 630a, 630b may be, for example, about 10:1, about 20:1, about 30:1, about 40:1, about 50:1, about 60:1, about 70:1, about 80:1, about 90:1, about 100: 1, about 110:1, about 120:1, or more than about 120:1. In one example, mirrors 690 are about 11.1 meters long and about 0.10 meters wide (aspect ratio about 112:1). In another example, mirrors 690 are about 11.1 meters long and about 0.13 meters wide (aspect ratio about 86:1). In some variations, mirrors 690 may be assembled from shorter length mirrors, having lengths as short as about 1 meter, positioned end to end.
Although
Referring now to
One of ordinary skill in the art will recognize that linear Fresnel collectors are known in the art, and that features of the support structures and the general arrangement of the reflectors with respect to the receiver are intended as schematic illustrations representing numerous configurations known in the art.
This disclosure is illustrative and not limiting. Further modifications will be apparent to one skilled in the art in light of this disclosure and are intended to fall within the scope of the appended claims. All publications and patent applications cited in the specification are incorporated herein by reference in their entirety as if each individual publication or patent application were specifically and individually put forth herein.
This application is a Continuation of U.S. patent application Ser. No. 12/622,416 filed Nov. 19, 2009, and entitled RECEIVER FOR CONCENTRATING PHOTOVOLTAIC-THERMAL SYSTEM, which is incorporated herein by reference in its entirety.
Number | Date | Country | |
---|---|---|---|
Parent | 12622416 | Nov 2009 | US |
Child | 12887958 | US |