Solar modules with tracking and concentrating features

• US 20070251569A1
• Filed: 01/25/2007
• Published: 11/01/2007
• Est. Priority Date: 01/25/2006
• Status: Active Grant

• Current Assignee: Intematix Corporation
• Original Assignee: Intematix Corporation
• Inventors: Wang, Gang, Shan, Wei, Xiang, Xiao
• Granted Patent: US 7,569,764 B2
• Time in Patent Office: Days
• US Class Current: 136/246
• CPC Class Codes: F24S 2020/16 Preventing shading effects
• CPC Class Codes: F24S 2023/834 trough-shaped
• CPC Class Codes: F24S 2023/872 Assemblies of spaced reflective elements on common support, e.g. Fresnel reflectors
• CPC Class Codes: F24S 2030/136 for moving several solar collectors by common transmission elements
• CPC Class Codes: F24S 23/30 with lenses
• CPC Class Codes: F24S 23/80 having discontinuous faces
• CPC Class Codes: F24S 30/48 with three or more rotation axes or with multiple degrees of freedom
• CPC Class Codes: F24S 40/40 Preventing corrosion; Protecting against dirt or contamination
• CPC Class Codes: F24S 40/42 Preventing condensation inside solar modules by venting F24S40/53
• CPC Class Codes: F24S 50/20 for tracking
• CPC Class Codes: H01L 31/052 Cooling means directly associated or integrated with the PV cell, e.g. integrated Peltier elements for active cooling or heat sinks directly associated with the PV cells cooling means in combination with the PV module H02S40/42
• CPC Class Codes: H01L 31/0543 comprising light concentrating means of the refractive type, e.g. lenses
• CPC Class Codes: H01L 31/0547 comprising light concentrating means of the reflecting type, e.g. parabolic mirrors, concentrators using total internal reflection
• CPC Class Codes: H02S 20/32 specially adapted for solar tracking
• CPC Class Codes: H02S 40/44 Means to utilise heat energy, e.g. hybrid systems producing warm water and electricity at the same time directly associated with the PV cell or integrated with the PV cell H01L31/0525
• CPC Class Codes: H10N 10/13 characterised by the heat-exchanging means at the junction
• CPC Class Codes: Y02E 10/47 Mountings or tracking
• CPC Class Codes: Y02E 10/52 PV systems with concentrators
• CPC Class Codes: Y02E 10/60 Thermal-PV hybrids

Abstract

Disclosed are fixed solar-electric modules having arrays of solar concentrator assemblies capable of separately tracking movements through one or two degrees of rotational freedom to follow the movement of the sun daily and/or seasonally. The concentrators can include optical elements to direct and concentrate light onto photovoltaic and/or thermoelectric receivers for generation of electric current.

Claims

1. A solar-electric module having a solar tracking capability, the module comprising:

an array of concentrator assemblies, each assembly comprising on or more of photovoltaic receivers or thermoelectric receivers and comprising one or more optical concentrators configured to reflect or refract solar radiation onto the receivers when aperture normals of the optical concentrators are aligned with the sun; and

a tracking mechanism for maintaining functional alignment of the aperture normals with the sun by at least once daily alignment adjustments.

2. The system of claim 1, wherein the module comprises a stationary frame to which the concentrator array members are pivotably mounted.

3. The solar module of claim 1, wherein the concentrator assemblies possess at least one degree of freedom of rotation in an arch of at least 23 degrees.

4. The solar module of claim 1, wherein the optical concentrators are selected from the group consisting of:

a convex lens, a GRIN lens having a refractive index gradient increasing from its center plane, a Fresnel lens, a hybrid lens having a cylindrical lens in the center and a set of total internal refection (TIR) structures on the edges, a parabolic reflector, and a pair of compound parabolic reflective mirrors.

5. The solar module of claim 1, wherein the optical concentrator is configured to concentrate light from the sun onto the receivers with concentration factors from about 10-fold to about 50-fold.

6. The solar module of claim 1, wherein the tracking mechanism comprises an array of light detectors that provide a first pattern of detector signals when the concentrator aperture normals are aligned with the sun and a second different pattern of detector signals when the normals are no aligned with the sun.

7. The solar module of claim 1, wherein power used to drive the tracking mechanism adjustments is derived from one or more flat-plate solar cells without associated optical concentrators.

8. The solar module of claim 1, further comprising a backing plate heat sink in thermal conductive contact with the concentrator assemblies.

9. The solar module of claim 1, further comprising a coolant fluid in a conduit mounted in thermoconductive contact with the photovoltaic receivers or the thermoelectric receivers.

10. The solar module of claim 1, wherein the array of concentrator assemblies comprises a hybrid array containing both photovoltaic and thermoelectric receivers.

11. The solar module of claim 10, wherein the receivers are configured with the photovoltaic receivers mounted in thermoconductive contact with the thermoelectric receivers.

12. The solar module of claim 10, wherein the concentrator array further comprises prisms, diffraction gratings or optical band pass filters that direct visible light to the photovoltaic receivers and infrared light to the thermoelectric receivers.

13. The solar module of claim 1, wherein the concentrator assemblies are mounted to the module with a single degree of rotational freedom about an axis.

14. The solar module of claim 13, wherein the rotational axes of the concentrators are aligned east-west and the rotational freedom is not less than 23 degrees.

15. The solar module of claim 13, wherein the rotational axes of the concentrators are aligned north-south and the rotational freedom is not less than 180 degrees.

16. A solar-electric module comprising:

an array of concentrator assemblies each comprising a photovoltaic receiver or thermoelectric receiver, and comprising one or more optical reflectors or lenses configured concentrate sunlight by reflection or refraction onto the photovoltaic receiver or thermoelectric receiver; and

,

a tracking mechanism configured to separately move each member of the concentrator array through two degrees of rotational freedom;

whereby the members of the concentrator array are moved in unison to each follow the relative movement of the sun across the sky.

17. The system of claim 16, wherein the module comprises a stationary frame to which the concentrator array members are each pivotably mounted.

18. The system of claim 16, wherein the concentrator assemblies comprise both photovoltaic cells and thermoelectric cells.

19. The system of claim 16, wherein the concentrator assemblies comprise optical concentrators selected from the group consisting of:

a lens, a parabolic reflector, a compound parabolic mirror, a compound hyperbolic mirror, a compound elliptic mirror, a compound triangular concentrator, a dielectric total internal reflection concentrator, a refractive and reflective concentrator, a refractive optical device, a reflective optical device, a internal reflection optical device, and combinations thereof.

20. The system of claim 19, wherein the lens is selected from the group consisting of a convex lens, a GRIN lens, a Fresnel lens, a hybrid lens having a regular lens in the center and a set of total internal refection (TIR) structure on the edges, and combinations thereof.

21. The system of claim 16, wherein the concentrator assemblies are configured to provide a solar radiation concentration factor ranging from about 100-fold to about 250-fold.

22. The system of claim 16, wherein the tracking mechanism comprises:

a top plate comprising a perforated plane;

a bottom plate that can be translated relative to the top plate in two perpendicular directions along the plane; and

,

one or more spheroids attached to each concentrator array member and retained between the top plate and bottom plate with the optical concentrators projecting above the top plate;

whereby relative motion of the top and bottom plate rolls the spheroids and rotates the concentrators in unison through one or two degrees of rotational freedom.

23. The system of claim 22, wherein the tracking mechanism further comprises a frame board mounted between the top plate and bottom plate and comprising sockets to receive the spheroids.

24. The system of claim 16, wherein the tracking system first degree of freedom ranges through at least 23 degrees of rotation and the second degree of freedom ranges through at least 180 degrees of rotation.

25. A solar concentrator system with moisture abatement capability, the system comprising:

at least one sealed solar concentrator module having a channel fluidly connecting an internal space of the module to an external environment, whereby air can flow into and out of the module; and

a water vapor trap in fluid contact with the channel and comprising a condenser or chemical desiccant to remove water vapor from air flowing through the channel.

26. The solar concentrator system of claim 25, wherein the water vapor trap is positioned outside the module.

27. The solar concentrator system of claim 25, wherein the water vapor trap is further configured to release water upon heating of the trap while air is flowing from the module, through the trap, and out to the external environment.

28. The solar concentrator system of claim 25, wherein the trap is configured to be heated by sunlight, surrounding ambient hot air, or electrical current when air is flowing out of the module.

29. The solar concentrator system of claim 25, wherein the water vapor trap comprises a moisture absorbing material that tends to absorb water vapor when cooled and tends to release water when heated.

30. The solar concentrator system of claim 29, wherein the moisture absorbing material is selected from the group consisting of:

silica gel, cobalt chloride, calcium hydride, a molecular sieve, zeolite, clay, lithium chloride (LiCl), and sodium polyacrylate.

31. The solar concentrator system of claim 25, wherein the water vapor trap comprises a black outer surface.

32. A solar concentrator system with moisture abatement capability, the system comprising:

at least one solar concentrator module sealed but for a channel fluidly connecting an internal space of the module to an external environment through a water vapor trap; and

the channel comprising a coiled tube with an internal diameter of less than 0.5 mm between the vapor trap and the external environment,

thereby reducing diffusion of water vapor from external air to the water vapor trap.

33. A method of abating condensation inside solar concentrator module, the method comprising:

providing a channel fluidly connecting an internal space of the module to an external environment through a water vapor trap; and

,

heating the vapor trap when air is flowing from the interior space to the external environment.