WO2014160856A1

WO2014160856A1 - Module case for concentrated photo voltaic with integral cooling channels

Info

Publication number: WO2014160856A1
Application number: PCT/US2014/032001
Authority: WO
Inventors: James P. CRIMMINS
Original assignee: Brightleaf Technologies, Inc.
Priority date: 2013-03-27
Filing date: 2014-03-27
Publication date: 2014-10-02

Abstract

A solar energy system includes a chassis for solar receivers, and which is equipped with channels for a cooling medium. In an example, solar receivers are arranged in rows on a plate that is set on a bottom of the chassis. The channels are integrally formed in the bottom of the chassis and define a flow circuit in which cooling fluid selectively flows. The flow circuit is strategically formed to extend adjacent to rows so that the receivers are in thermal communication with the flow circuit. Thus when fluid is directed into the flow circuit, thermal energy is exchanged between the receivers and fluid.

Description

MODULE CASE FOR CONCENTRATED PHOTO VOLTAIC WITH INTEGRAL

COOLING CHANNELS

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of co-pending U.S. Provisional Application Serial No. 61/805,706, filed March 27^th, 2013, the full disclosure of which is hereby incorporated by reference herein for all purposes.

BACKGROUND

1. Field of Invention

[0002] The invention relates generally to an improved efficiency concentrated photovoltaic (CPV) system. More specifically, the invention relates generally to a method and system for transferring waste heat from a CPV system.

2. Description of Prior Art

[0002] Converting solar energy into - electricity is often accomplished by directing the solar energy onto one or more photovoltaic cells. The photovoltaic cells are typically made from semiconductors that can absorb energy from photons from the solar energy, and in turn generate electron flow within the cell. A solar panel is a group of these cells that are electrically connected and packaged so an array of panels can be produced; which is typically referred to as a flat panel system. Solar arrays are generally oriented so they receive rays of light directly from the source.

[0003] Some solar collection systems concentrate solar energy by employing curved solar collectors that concentrate light onto a solar cell. The collectors are often parabolic having a concave side and a convex side, and usually with the concave side facing forward for directing reflecting light onto a receiver. Receivers typically include a photovoltaic cell that has a higher performance than cells used in flat panel systems. A reflective surface is typically on the concave side of each of the collectors for reflecting the solar energy towards the receiver. The concave configuration of the reflective surface converges reflected rays of solar energy into a concentrated image that is superimposed onto the receiver. Other solar energy systems employ Fresnel lenses to concentrate solar energy that is superimposed onto a receiver.

[0004] The concentrated solar energy often has an intensity far exceeding that achieved with a flat panel system. Images from Fresnel lenses typically have an intensity of around 800 times that of flat panels, whereas curved collectors can project up to about 1500 times the intensity of sunlight onto a receiver over that of a flat panel system. Because currently known cells do not convert all the solar energy received into electricity, substantial heating occurs on the receiver that can damage the cells unless the thermal energy accumulated on the receiver can be transferred elsewhere. Thus solar energy systems that project concentrated solar energy onto receivers require cooling systems for transferring heat away from the receivers.

SUMMARY OF THE INVENTION

[0005] Provided herein is a solar energy system having a chassis for solar receivers, which is equipped with channels for a cooling medium. In an example, solar receivers are arranged in rows on a plate that is set on a bottom, of the chassis. The channels are integrally formed in the bottom of the chassis and define a flow circuit in which cooling fluid selectively flows. The flow circuit is strategically formed to extend adjacent to rows so that the receivers are in thermal communication with the flow circuit. Thus when fluid is directed into the flow circuit, thermal energy is exchanged between the receivers and fluid. In an example, heat fins extend from a bottom surface of the plate into the channels.

[0006] In an example t solar energy system includes a chassis, solar receivers arranged in a path on a planar member in the chassis, each having a photovoltaic solar cell that is selectively disposed in a path of solar rays and that is in selective electrical communication with an electrical load, so that when the solar receivers are exposed to the solar arrays, electricity generated in the solar receivers flows to the electrical load, a cooling circuit on a side of the planar member opposite the solar receivers, and a cooling medium selectively flowing through the cooling circuit that is in thermal communication with the solar receivers. The system can further include heat fins on a surface of the planar member that project into the cooling circuit and into contact with the cooling medium. The cooling circuit optionally is made up of channels integrally formed along a bottom of the chassis and the planar member is a plate from a receiver assembly. In an example, the planar member is the bottom of the chassis and wherein the cooling circuit includes channels formed in a generally planar channel assembly mounted on a side of the planar member opposite the solar receivers. The cooling medium can be water, glycol, or combinations thereof. A transformer can be used to transform the electricity to a designated type, voltage, or current for use by the electrical load. The cooling circuit can be in communication with a well for storing thermal energy in a subterranean formation. Fresnel lenses may be included for concentrating solar energy onto the solar receivers.

[0007] In another example, disclosed is solar energy system having a chassis, solar receivers arranged in rows on a planar member in the chassis, each having a photovoltaic solar cell that is selectively disposed in a path of solar rays and that is in selective electrical communication with an electrical load, so that when the solar receivers are exposed to the solar arrays, electricity generated in the solar receivers flows to the electrical load, a plate on a side of the planar member opposite the solar receivers and having integrally formed channels that form a cooling circuit and that are aligned with the rows, and a cooling medium selectively flowing through the cooling circuit that is in thermal communication with the solar receivers. The system can also have an inlet and outlet for the cooling medium that are at opposite corners of the cooling circuit, and wherein the channels comprise header channels on opposing ends of the plate and channels extending between the header channels. Optionally, an inlet and outlet for the cooling medium can be included that are adjacent one another, and wherein the cooling circuit has an end connected to the inlet and an opposite end connected to the outlet, and follows a generally serpentine path between the inlet and the outlet. Heat fins may be included on a surface of the planar member that project into the cooling circuit and into contact with the cooling medium. The planar member can be a plate from a receiver assembly. Alternatively, the planar member can be the bottom of the chassis. The cooling medium can be water, glycol, or combinations thereof. A transformer can be included that transforms the electricity to a designated type, voltage, or current for use by the electrical load. The cooling circuit can be in communication with a well for storing thermal energy in a subterranean formation. An alternative Fresnel lenses can be included for concentrating solar energy onto the solar receivers.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Some of the features and benefits of the present invention having been stated, others will become apparent as the description proceeds when taken in conjunction with the accompanying drawings, in which:

[0003] FIG. 1 is a perspective sectional view of concentrated photovoltaic (CPV) module in accordance with the present invention.

[0004] FIG. 2 is a perspective view of an example of a chassis that is part of the module of FIG. 1 and in accordance with the present invention.

[0005] FIG. 2A is a schematic of a cooling circuit path in accordance with the present invention.

[0006] FIG. 3 is a perspective view of an example of a receiver assembly that is part of the module of FIG. 1 and in accordance with the present invention.

[0007] FIG. 4 is a sectional view of an alternate embodiment of the CPV module of FIG. 1 and in accordance with the present invention.

[0008] FIG. 5 is a schematic view of a heater transfer circuit for use with the CPV module of FIG. 1 and in accordance with the present invention.

[0009] While the invention will be described in connection with the preferred embodiments, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the invention as defined by the appended claims. DETAILED DESCRIPTION OF INVENTION

[0010] The method and system of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings in which embodiments are shown. The method and system of the present disclosure may be in many different forms and should not be construed as limited to the illustrated embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey its scope to those skilled in the art. Like numbers refer to like elements throughout. In an embodiment, usage of the term "about" includes +/- 5% of the cited magnitude. In an embodiment, usage of the term "substantially" includes +/- 5% of the cited magnitude.

[0011] It is to be further understood that the scope of the present disclosure is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. In the drawings and specification, there have been disclosed illustrative embodiments and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation. Accordingly, the improvements herein described are therefore to be limited only by the scope of the appended claims.

[0012] Shown in a perspective and partial sectional view in Figure 1 , is an example of a concentrated photovoltaic (CPV) module 10 for converting solar energy into electricity. The module 10 includes a chassis 12 shown made up of planar sidewalls 1 1 , 14₂, 14₃ and a bottom 16 with a generally rectangular outer periphery. The sidewalls 14], 14₂, 14₃ project from peripheral edges of the bottom 16 and in a direction generally normal to the bottom 16. A space 18 is defined within the region bounded by sidewalls 14], 14₂, 14₃ and bottom 16. Depressions in the bottom 16 define channels 20i-20₆ shown extending in a direction general parallel with sidewalls 14_{l s} 14₃ and normal to sidewall 14₂. Channels 20]-20₆ are not limited to the generally rectangular cross section shown, but can have any other cross sectional configuration, such as triangular, oval, semi-circular, to name a few. Further included in the example of Figure 1 is a header channel 22 shown formed in the bottom 16 and intersecting an end of each channel 2 - 20₆ adjacent sidewall 14₂. In an example, header channel 22 has a cross sectional configuration the same or substantially similar to that of channels 20i-20₆. Optionally, header channel 22 can intersect channels 20]-20₆ at different locations that what is illustrated, and module 10 can include more than one header channel 22.

[0013] A receiver assembly 24 is shown in the chassis 12 and mounted on the bottom 16. In an embodiment, receiver assembly 24 includes a planar plate 26, shown having a rectangular outer periphery which extends proximate to sidewalls 14], 14₂, 14₃. An optional lip 28 projects upward from plate along its outer edge. Receivers 30 are illustrated on a surface of plate 26 facing space 18 and arranged in rows 32, where rows 32 generally align with channels 20i-20₆. The example of Figure 1 further includes a planar Fresnel plate 34 mounted on upper ends of sidewalls 14i , 14₂, 14₃ that are distal from bottom 16. Fresnel lenses 36 are included with Fresnel plate 34, and which can be integrally formed into Fresnel plate 34, or laminated thereon as a separate layer. In the illustrated example, solar energy is schematically represented by rays R which contact Fresnel lenses 36 on a side opposite space 18; the solar energy is redirected into a conically shaped beam 38 shown directed into the space 18. Fresnel lenses 36 and receivers 30 are strategically located so that an end of beam 38 distal from Fresnel plate 34 is superimposed onto receiver 30. Electricity generated in receivers 30 from exposure to solar energy can flow to a user(s) via connectors 40] , 40₂ shown mounted onto bottom 16 between the outer perimeter of plate 26 and sidewalls 14], 14₂, 14₃.

[0014] As shown, cross sectional area of the beam 38 reduces with distance from the Fresnel lens 36 to concentrate the solar energy from the rays R, so that the intensity of the beam 38 when superimposed onto the receiver 30 significantly exceeds intensity of the solar energy contacting Fresnel plate 34. As will be described in more detail below, channels 20]-20₆ are strategically aligned with rows 32, so that when a cooling medium is provided in channels 20i-20₆, thermal energy in the modules 30 transfers from the modules 30 to the cooling medium. Examples of the cooling medium include water, glycol, and combinations thereof.

[0015] Referring now to Figure 2. an example embodiment of chassis 12 is shown in a perspective view and which illustrates another sidewall 14₄ extending upward from bottom 16 and between lateral ends of sidewalls 14], 14₃ to define a lateral peripheral boundary to space 18. Further illustrated in Figure 2 is a header channel 42 formed in bottom 16 and which intersects ends of channels 20i-20₆ distal from header channel 22. Channels 20i-20₆, 22, 42 are interconnected and form a generally rectangular cooling circuit 43. In the illustrated example, an inlet 44 and outlet 46 for cooling circuit 43 are provided at generally diagonally distal ends from one another in the cooling circuit 43. Additionally illustrated in this embodiment is that the cooling circuit 43 is integrally formed into a single component, i.e. the bottom 16 of the chassis 12. More specifically, inlet 44 is depicted in the bottom 16 and proximate intersection of channel 20] and header channel 22. Outlet 46 (shown in phantom) is in the bottom 16 and proximate intersection of channel 20₆ and header channel 42. Arrows illustrate example directions of a cooling medium when flowing through the cooling circuit 43. The placement of the inlet 44 and outlet 46 results in each flow path between the inlet 44 and outlet 46 having similar lengths and thus substantially equal flow adjacent each module 30, Inlet 44 and outlet 46 placements are not limited to the locations shown. Examples exist where inlet 44 and outlet 46 are proximate one another, and flow barriers (not shown) divert cooling medium flow throughout the circuit 43.

[0016] An alternate embodiment of the cooling circuit 43A is schematically illustrated in Figure 3A. Shown is a single channel 20A having an inlet 44A and outlet 46A for respectively receiving and discharging the cooling medium from the circuit 43 A. The channel 20A is shown being a single element and having a serpentine configuration. Strategically configuring the channel 20A forms a flow path for the cooling medium that passes adjacent each of the receivers 30 (Figure 1), so that thermal energy from the receivers 30 can be transferred into the cooling medium in the channel 20A for cooling the receivers 30.

[0017] A perspective partial sectional view of the receiver assembly 24 is shown in Figure 3. In this example, solar cells 47 are shown provided with the modules 30, that in an embodiment are photovoltaic cells, and which may include silicon, doped silicon, or combinations. In an alternative, solar cells 47 are multi-junction cells. As shown, heat fins 48 are provided on a lower surface of the plate 26 and opposite on which modules 30 are mounted. Moreover, heat fins 48 are disposed so that they are substantially aligned with a corresponding module 30 on an opposite side of plate 26. In an example, thermal energy generated by directing beams 38 (Figure 1) onto the modules 30, is transferred from modules 30, to heat fins 48. As the rows 32 of modules 30 align with channels 20 j - 20₆, heat fins 48 project into channels 20j - 20₆, and in turn transfer heat to cooling medium flowing in channels 201 - 20₆. In the illustrated example, heat fins 48 are elongate plate like members having an elongate length, a depth, and thickness, and wherein the fins 48 are oriented so that their lengths are substantially parallel with a direction of flow of the cooling medium through the channels 201 - 20₆.

[0018] An alternate embodiment of a CPV module 10A is provided in perspective partial sectional view in Figure 4. This example embodiment, the bottom 16A is substantially planar and without depressions or channels, and has modules 30 mounted directly on its upper surface. A channel assembly 50 is shown coupled onto a lower surface of chassis 12A and under the bottom 16A. Channel assembly 50 is a generally plate like member with integrally formed depressions within and along substantially parallel paths that define channels 52] - 52₆; where channels 52] - 52₆ are similar in configuration and function to channels 20] - 20₆ of Figure 2. Moreover, heat fins (not shown) aire provided on the bottom surface of chassis 12A that are strategically disposed so they project into channels 521 - 52₆. In this example, heat in the modules 30 transfers to the heat fins and then to the cooling medium flowing in the channels 52] - 52 , thereby transferring heat away from modules 30. This embodiment further isolates the cooling medium from modules 30, by preventing contamination or other damage to the modules 30 from cooling medium. In an alternative embodiment, a single channel (not shown) is formed in the channel assembly 50 or bottom 16 (Figure 2). Instead of headers for receiving and discharging a flow of cooling medium, the single channel changes direction between adjacent rows 32 to have thermal communication with each module 30.

[0019] Figure 5 illustrates a plurality of modules 10|-10_n that are arranged into an array 54 and form part of an example CPV system 56 for converting solar energy to electricity. System 56 includes a line 58, which communicates with connectors 40i, 40₂ (Figure 1), for transmitting electricity from array 54 to an associated structure 60 for use therein. A transformer 62 is shown optionally included in line 58 for transforming electricity in line 58 to a designated type (e.g. alternating or direct current), voltage, and or current. An exit flow circuit 64 is shown routed from array 54, where it carries cooling medium heated by exposure to modules 30 to structure 60, or optionally to wells 66 shown formed in a formation 68 beneath structure 60. Thermal energy within cooling medium may be transferred to and stored within formation 68, and which may be withdrawn therefrom at a later time. A return flow circuit 70 provides a path for the cooling medium back to array 54.

[0020] An advantage of the cooling circuit 43 (Figure 2) integrally formed into components of the chassis 12 is that the solar receivers 30 (Figure 1) can be cooled with forced convection without added piping and fittings, thereby avoiding manufacturing difficulties and expenses. An additional advantage of the cooling circuit 43 (Figure 2) disclosed herein is that its positioning does not block solar energy from reaching the receiving 30 (Figure 1) thereby not introducing shading to the system. Further, higher rates of return are expected as piping systems have a greater percentage of exposed surface area compared to the channels 20 described herein, and that there is more direct heat transfer between the cooling medium and receivers 30.

10021 ] The present invention described herein, therefore, is well adapted to carry out the objects and attain the ends and advantages mentioned, as well as others inherent therein. While a presently preferred embodiment of the invention has been given for purposes of disclosure, numerous changes exist in the details of procedures for accomplishing the desired results. These and other similar modifications will readily suggest themselves to those skilled in the art, and are intended to be encompassed within the spirit of the present invention disclosed herein and the scope of the appended claims.

Claims

CLAIMS What is claimed is.

1. A solar energy system comprising: a chassis; solar receivers arranged in a path on a planar member in the chassis, each having a photovoltaic solar cell that is selectively disposed in a path of solar rays and that is in selective electrical communication with an electrical load, so that when the solar receivers are exposed to the solar arrays, electricity generated in the solar receivers flows to the electrical load; a cooling circuit on a side of the planar member opposite the solar receivers; and a cooling medium selectively flowing through the cooling circuit that is in thermal communication with the solar receivers.

2. The solar energy system of claim 1 , further comprising heat fins on a surface of the planar member that project into the cooling circuit and into contact with the cooling medium.

3. The solar energy system of claim 1, wherein the cooling circuit comprises channels integrally formed along a bottom of the chassis and the planar member comprises a plate from a receiver assembly.

4. The solar energy system of claim 1 , wherein the planar member comprises the bottom of the chassis and wherein the cooling circuit comprises channels formed in a generally planar channel assembly mounted on a side of the planar member opposite the solar receivers.

5. The solar energy system of claim 1 , wherein the cooling medium comprises a fluid selected from the group consisting of water, glycol, and combinations thereof.

6. The solar energy system of claim 1 , wherein a transformer transforms the electricity to a designated type, voltage, or current for use by the electrical load.

7. The solar energy system of claim 1 , wherein the cooling circuit is in communication with a well for storing thermal energy in a subterranean formation.

8. The solar energy system of claim 1 , further comprising Fresnel lenses for concentrating solar energy onto the solar receivers.

9. A solar energy system comprising: a chassis; solar receivers arranged in rows on a planar member in the chassis, each having a photovoltaic solar cell that is selectively disposed in a path of solar rays and that is in selective electrical communication with an electrical load, so that when the solar receivers are exposed to the solar arrays, electricity generated in the solar receivers flows to the electrical load; a plate on a side of the planar member opposite the solar receivers and having integrally formed channels that form a cooling circuit and that are aligned with the rows; and a cooling medium selectively flowing through the cooling circuit that is in thermal communication with the solar receivers.

10. The solar energy system of claim 9, further comprising an inlet and outlet for the cooling medium that are at opposite comers of the cooling circuit, and wherein the channels comprise header channels on opposing ends of the plate and channels extending between the header channels.

1 1. The solar energy system of claim 9, further comprising an inlet and outlet for the cooling medium that are adjacent one another, and wherein the cooling circuit has an end connected to the inlet and an opposite end connected to the outlet, and follows a generally serpentine path between the inlet and the outlet.

12. The solar energy system of: claim 9, further comprising heat fins on a surface of the planar member that project into the cooling circuit and into contact with the cooling medium.

13. The solar energy system of claim 9, wherein the planar member comprises a plate from a receiver assembly.

14. The solar energy system of claim 9, wherein the planar member comprises the bottom of the chassis.

15. The solar energy system of claim 9, wherein the cooling medium comprises a fluid selected from the group consisting of water, glycol, and combinations thereof.

16. The solar energy system of cla ri 9, wherein a transformer transforms the electricity to a designated type, voltage, or current for use by the electrical load.

17. The solar energy system of claim 9, wherein the cooling circuit is in communication with a well for storing thermal energy in a subterranean formation.

18. The solar energy system of claim 9, further comprising Fresnel lenses for concentrating solar energy onto the solar receivers.