WO1996024954A1

WO1996024954A1 - Non-tracking solar concentrator heat sink and housing system

Info

Publication number: WO1996024954A1
Application number: PCT/US1995/001622
Authority: WO
Inventors: Christopher P. Kinkaid
Original assignee: Solardyne Corporation
Priority date: 1995-02-09
Filing date: 1995-02-09
Publication date: 1996-08-15
Also published as: AU1872995A

Abstract

The invention discloses a system for solar concentration which achieves uniform concentration onto interchangeable receivers at wide angles of acceptance. The preferably single element operates as a non-tracking concentrator (10) while simultaneously functioning as a heat sink. The shaping provides strength and maintains even optical spacing and also serves as the housing for the solar receiver. Operating as a heat sink, the concentrator (10) conducts heat from the receivers (16) to the reflectors (13) which function as a radiator cooling the receiver. Convective cooling also adds to the efficiency of the system. This device provides optically for wide angles of solar incidence and functions as an isotropic concentrator through these hours. The static concentrator is a standardized solar optical deployment system which provides of receivers which are interchangeable for photovoltaic, photochemical, and photothermal applications.

Description

DESCRIPTION

NON-TRACKING SOLAR CONCENTRATOR HEAT SINK AND HOUSING SYSTEM

Cross-Reference to Related Applications This application is a continuation-in-part of co-pending application Serial No. 08/109,827; filed on August 20, 1993.

Field of the Invention The present invention relates to solar cell concentrator assemblies and, more particularly, to improved structures for the capture of solar radiation in such assemblies.

Background of the Invention Various types of solar collectors are known. A number of the collectors incorporate V-shaped troughs as the collection device including U.S. Patent Nos. 3,232,795 to Gillette; 4,099,515 to Schertz; 4,789,408 to Fitzsimmons; 3,350,234 to Ule; 4,217,881 to Brent; and 4,295,463 to Citron. However, existing V-shaped trough solar collectors present a number of problems. First, most of these solar collectors require tracking devices to track the solar radiation in order to ensure operation of the solar collectors over a longer time period during the day thereby generating a sufficient amount of energy to make the solar collectors energy efficient. Such tracking devices are required because these solar concentrators have an angle of acceptance which is quite narrow. Those solar concentrators that have achieved a wider angle of acceptance have usually done so at the expense of isotropic or evenly distributed irradiation of the solar receiver. Additionally, existing V-shaped solar concentrators in order to incorporate a heat sink function require additional hardware and materials which are both bulky and expensive to operate since the material of the concentrator itself is not suitable for heat sink functions. Yet another problem with these tracking concentrators is the number of parts required to make the concentrator operational, all of which are subject to wear and require periodic replacement. These concentrators can require a large amount of time and mechanical hardware to position and keep the solar receivers in place. A V- shaped solar concentrator not exhibiting the drawbacks of existing V-shaped trough concentrators is therefore desirable.

Brief Summary of the Invention It is an object of the present invention to provide for an improved V-shaped trough solar concentrator.

It is yet another object of the present invention to provide for a V-shaped trough concentrator having a wide acceptance angle and not requiring tracking hardware.

It is still another object of the present invention to provide for a V-shaped trough solar concentrator providing isotropic irradiation of the solar receiver.

Yet another object of the present invention is to provide a V-shaped trough solar concentrator fabricated in such a way as to not require additional hardware or materials for its heat sink.

Still another object of the present invention is to provide for a V-shaped trough solar concentrator which can incorporate the functions of a solar reflector, heat sink, and receiver housing in a single element structure.

Yet another object of the present invention is to provide for a single element V-shaped trough solar concentrator.

Still another object of the present invention is to provide for a V-shaped trough solar concentrator in which irradiated receivers can accomplish different functions such as photothermal and photochemical operations interchangeably.

A further object of this invention is to provide a solar concentrator having improved convective cooling characteristics due to enhanced air flow around and through the unit. Another object is to provide a solar concentrator having optimized wall shape such that improved reflection of incident light onto receiving cells occurs. Another object is to provide for an improved solar concentrator which has a reflective coating disposed above the solar receiving cells which is transmissive for photons above, but reflective for photons below the bandgap of the receiving cells. These and other objects of the present invention are accomplished by a single element non-tracking solar concentrator heat sink and housing for holding solar receivers comprising at least one sheet of solar reflective material structured so as to form at least one V-shaped trough, each of the at least one V-shaped troughs having two walls and a base, the base having two sides, each wall having an upper edge and a lower edge. Each trough has a base positioned between the lower edges of the two walls of the at least one trough. A solar receiver housing area is located on one side of the base. The at least two walls and the base may be formed of a heat conducting material which allows the concentrator to act as a heat sink. At least a portion of the joined at least two walls and base may be in contact with a structural member. Preferably, the heat conducting material is aluminum. Preferably, each of the at least one V-shaped trough's base and walls are joined at an angle of 115°-120°. Preferably, the concentrator is formed of only one sheet of solar reflective material so that the concentrator can be formed with a single element.

Brief Description of the Drawings Figure 1 is a perspective view of a non-tracking solar concentrator of the present invention;

Figure 2 is a partially exploded side view of the non-tracking solar concentrator of the present invention.

Figure 3 is a top view of one embodiment of the solar concentrator of the present invention.

Figure 4 is a diagram of the present invention operating as a heat sink.

Figure 5 is a diagram illustrating the wider angle of acceptance achieved with the non-tracking solar concentrator of the present invention. Figure 6 is an alternative embodiment of the non-tracking solar concentrator of the present invention.

Figure 7A is another embodiment of the non-tracking solar concentrator showing the dual function drain hole\convection cooling mechanism.

Figure 7B is another embodiment of the non-tracking solar concentrator showing the dual function drain hole\convection cooling mechanism, also showing faceted walls.

Figure 8 is a side view showing modular extension of the non-tracking solar concentrator via overlap of units.

Figure 9A is a detailed sectional view of a preferred embodiment of the non- tracking solar concentrator showing segments, the facets of which are bent to enhance solar concentration.

Figure 9B is a detailed elevational view of a preferred embodiment of the non- tracking solar concentrator showing segments, the facets of which are bent to enhance solar concentration.

Figure 10 is a detailed view of one preferred embodiment for the solar receiver element.

Description of the Preferred Embodiment

Referring now to Figure 1, an embodiment of the solar concentrator 10 of the present invention is shown. The solar concentrator is comprised of at least one sheet 11 of solar reflective material structured so as to form at least one V-shaped trough 12. Each of the at least one V-shaped troughs 12 has two walls 13 and a base 14. Referring now to Figure 2, another view of the solar concentrator 10 of the present invention is shown. The preferably single sheet 11 of reflective material is shown shaped into V-shaped troughs 12. Preferably, the at least one sheet 11 is formed of aluminum. The preferred material is the Everbrite™ material manufactured by Alcoa Aluminum Corporation. If aluminum is used, the single element solar concentrator can be fully recycled, thereby providing an additional benefit of the instant invention. Additionally, the solar concentrator 10 of the present invention is capable of inexpensive and easy manufacture. Moreover, the solar concentrator assembly also exhibits a structural rigidity and strength which is desirable for the stresses of the environment in which a solar concentrator must operate. These stresses include chemical degradation by ultra-violet light, wind loading, hail bombardment, saline corrosion, and thermal cycling each day and night. The high structural rigidity results from the reverse angle formed when two side walls 13 are joined at a seam for multiple sets of walls and bases. When the two side wall sections are formed with a bend, the reverse angle creates an inverse "roman arch" which dissipates stress and is extremely strong.

As seen in Figure 2, the solar receiving cells 16 are placed on one skid of the base 14 of the V-shaped trough 12. Preferably, the solar receivers 16 are placed on the side of the trough facing the incoming solar radiation 20. Preferably, the at least one sheet 11 is structured so as to create a fitted housing area 21 at the base of the V-shaped trough 12 to help position and secure the solar receiver 16. This can be accomplished by forming or bending the sheet to follow the dimensions of the solar receivers. A top view of one embodiment of the concentrator 10 and the receivers 16 is seen in Figure 3. The preferred method of securing the solar receiver 16 to the receiving trough 21 at the base of the V-shaped trough 12 is with a thermally conducting epoxy which is known in the art or with mechanical locks. Thus, because of the existence of the housing area 21, the receiver 16 can remain stable with respect to the reflecting walls 13 throughout operation thereby assuring more reliable operation of the solar concentrator. The preferred dimensions for the walls, base, and solar receivers are walls— 5 1/2" x 48"; base— 4 5/16" x 48"; and receivers—4 4/16" x 40". These, of course, can be varied and scaled.

To also achieve the function of the heat sink, the single element concentrator is preferably made of a heat conducting material such as aluminum. The concentrator

10 is then joined to a strut 18, which is preferably aluminum, which enhances the structural rigidity of the invention. The thin high surface area of the at least one sheet 11 operates as a very effective heat sink conducting heat away from the solar receivers through both convection and radiative cooling as seen in Figure 4.

In Figure 4, incident rays of solar radiation 20 contact the wall 13 of the concentrator 10 at points F. The major reflected rays 20 ' are reflected into housing area 21. The heat generated by the receiver(s) placed in area 21 is dissipated along a path of heat conduction G from the housing area 21 to the reflector walls 13 at a point or area H. At area or point H, heat is conducted away from the concentrator 10 and solar receivers) both orthogonally (I) and radially (J) in an efficient manner. Thus, heat is removed from the receivers by (1) conduction (heat transferring to reflecting walls of concentrator); (2) convention (ambient air or wind pulls heat off walls); and (3) radiation. The concentrator is an efficient heat sink due to its large surface area and high thermal conductivity.

The preferred angle of the walls 13 with respect to the base 14 is 115°-120°. However, significant variations can be taken on this angle with a proportional reduction in the efficiency of the irradiation of the cells 16. The 115° angle occurs between the base 14 and the lower edge 24 of the walls 13. The upper edges 22 of the walls 13 serve as a transition between each V-shaped trough.

Typical available concentrators require one or two axis tracking hardware. However, the increased complexity, vulnerability to error, and cost of tracking makes it undesirable. Static concentrators (i.e., concentrators not using tracking hardware) typically have been unable to produce a concentrator which is isotropic in its irradiance characteristics and is also capable of receiving solar radiation from wide angles. However, in the instant invention, isotropic irradiance is achieved at wide angles without the need for tracking. Tracking hardware moves the concentrator and solar cells with respect to the normal angle of the solar radiation. The instant invention accomplishes this by using an east-west orientation with the concentrator preferably facing south. At this normal angle, the concentrator remains non-moving during daily operation. As the seasonal angle changes from summer solstice to winter solstice, the instant invention can be adjusted during night operation allowing for a static non-moving orientation during daily operation.

The need for tracking hardware is also removed because of the concentrator's ability to obtain a wide angle of acceptance via the structure of the solar concentrator 10. First, the concentrator 10 is constructed only with walls 13 and without any side walls which can block solar radiation and shade the solar receiver 10. The concentrator 10 of the instant invention further achieves this wide acceptance angle by preferably ensuring that base 14 of the concentrator extends beyond the dimensions of the solar receiver 16.

A schematic illustrating the benefit of this extension on the angle of acceptance can be seen in Figure 5. If the walls 13 of the solar concentrator 10 are extended a distance e beyond the distance b of the solar receiver 16 on either end of the solar receivers, the solar concentrator 10 can accept solar irradiance and irradiate the receivers isotropically between the hours of 9:00 a.m. and 3:00 p.m. If the distance e was not added to the walls 13 of the solar concentrator 10, the solar receiver 16 could accept solar irradiance only during a brief period of the day unless tracking hardware was included to move the concentrator with respect to the normal angle of the incoming solar radiation. Thus, with the instant invention, east-west orientation previously mostly abandoned by those of skill in the art because of the inability to obtain even irradiance of solar cells can now be employed, thus avoiding the problem of the limited acceptance angle without the addition of tracking hardware.

As seen in Figure 6, the walls 13 of the solar concentrators 10 can also be parabolic in nature. Additionally, a number of solar concentrators 10 can operate together most efficiently with a slight overlap of the concentrators 10, thereby allowing tight stacking of the concentrators in defined areas.

In Figure 7, another embodiment of the non-tracking solar concentrator is shown having a plurality of apertures 25 disposed at intervals along the lower edge 24 of the walls 13. These apertures have the dual function of providing drainage for water that might otherwise become trapped in the base 14 and of providing enhanced convective cooling for the cells 16. The precise dimension and shape of these apertures is not critical so long as they do not disrupt the strength of the invention or conduction of heat to walls 13. These apertures may also be placed at the upper edge 22 of the walls 13 to further increase convective cooling.

In Figure 8, the modular extension of this invention via overlapping units is shown. This is accomplished simply by overlapping the walls 13 of the "V" shaped units. Alternatively, only the upper edges 22 of the walls 13 need to overlap. Structural rigidity is provided by affixing, for example by bolting, each module to the strut 18. Provision of the apertures increases convective cooling by allowing increased air flow around and through the unit. In Figure 9, a preferred embodiment of the invention is shown wherein the walls of the "V" are bent to optimize reflection of incident light 20 as reflected rays 20' onto the solar receiving cells 16. Referring to dimensions of walls— 5 1 2" x 48"; base— 4 5/16" x 48"; and receivers— 4 4/16" x 40", I have found, through theoretical calculation and empirical testing, that light is optimally focused onto the receiving elements by shaping the reflector walls 13 such that the angle between the base 14 and the lower edge 24 of the walls 13 is about 120°, decreasing to about 110°, either through a smooth, parabolic curve, or through segments, at the upper edge 22 of the walls 13. For ease of manufacture, I have found that decreasing the angle of sequential 1/2" segments by about 1.5°-1°, by simply bending the walls into segments, or facets 26, provides a very efficient concentrator, while at the same time, preserving a wide acceptance angle for non-tracking solar concentration. The geometric concentration ratio is 2.24 (aperture:receiver). This yields, with a reflectance efficiency of 85%, an optical concentration of 1.78. Therefore, theoretical yield would be expected to be no higher than 78%, and the increase in power produced could not exceed 78%, (assuming a yield of 1 for an identical cell under 1 sun conditions). The empirically measured increase in output is 70%, which demonstrates that this system is operating at very near to theoretical efficiency.

Referring now to Figure 10, a preferred embodiment shows a hermetically sealed solar receiver element. A major advantage of this embodiment is the incorporation of a heat rejection system which improves the efficiency of solar conversion. This is accomplished by using a filter, which prevents transmittance of photons of an energy which does not contribute to electrical output upon impinging the photovoltaic cells having a particular bandgap. As a concrete example of this, assume that silicon is used as the semi-conductor, photovoltaic material. Silicon has a bandgap of 1.1 ev. It would therefore be desirable to eliminate all photons from incident polychromatic solar light having an energy below this bandgap, as such photons only contribute to heat production without any contribution to electrical output. This object is achieved, as shown in Figure 10, by providing a filter, such as a film of silver, gold, copper or aluminum particles, on the underside of a protective glass or other light transmissive inert covering (layer 1). Placing the filter on the underside of the glass plate serves to protect the filter from some of the harshest environmental insults. This layer may be in the form of a thin film (layer 2), which rejects all photons having an energy below the bandgap. A pottent such as ethylvinylacetate (EVA, layer 3) or other encapsulant is provided to affix layers one (1) and two (2) to the substrate. Naturally, the filter could also be affixed to the underside of the glass using EVA or other adhesive means or encapsulants. The photovoltaic cells are provided as layer 4, including electrical leads, followed by another layer of EVA (layer 5) or other encapsulant which affixes the above layers to a heat dissipative metal (6), such as aluminum, preferably having a thermal coefficient of expansion that matches that of the base 14 of the solar concentrator 10. According to this embodiment, incoming rays of polychromatic light 27 enter the glass cover (layer 1) and are transmitted as polychromatic rays 28. Above-bandgap rays 29 are transmitted through the filter (layer 2) and onto the PV cells (layer 4). Below bandgap rays 30, which cannot contribute to power production, are rejected by the filter (layer 2) and are transmitted out of the unit as rejected rays 31, thereby eliminating their contribution to heating of the PV cells. Using a traditional current versus voltage (I-V) curve, power is defined as the product of the current and voltage, and is represented by the area under the I-V curve. The maximum theoretical power that can be produced by a given system is defined as the area under the curve defined by the short-circuit current (I_JC) and open-circuit voltage (V , and the maximum theoretical power is the product of these, I_IC V_oc. In practice, when a load is placed across a photovoltaic cell and the resistance is varied from zero (short-circuit conditions) to infinite (open-circuit conditions), an I-V curve is defined having an area under the curve (power) which is lower than the theoretical power defined by the I,_c-V_oc curve. At some point on the curve, typically at the knee of the curve, is a point called the maximum power point (mpp), where both the current and voltage are at a maximum (I_rapp.V_π)pp). The ratio between the actual power, L^_p-V^, and the theoretical power, I,_e.V_oc is called the fill factor (ff). That is ff=I--_pp.V_mpp/I,_c.V_0C. The closer a given system approaches to theoretical performance, the closer the ff approaches unity.

From the above discussion, it is apparent that if solar concentration achieves improved voltage at the mpp, then the ff is increased and the performance of the cell is improved. In a demonstration of the functioning of the system of the instant invention, a flash test at a normal angle (analogous to high noon lighting) conducted under standard test conditions (ambient temperature, 25°C; wind speed of 1 m sec; insolation of 1000 watts/m²), gave the following results:

TABLE 1

Four String, ~1.7 sun deployment of Single string, flat-plate, one this invention with 9 cells per string sun deployment, 9 cells per string

Parameter Test 1 Test 2 Average Test 1 Test 2 Average

"PP 65.068 65.073 65.0705 9.99 9.993 9.99915

" mpp 16.203 16.21 16.2065 4.59 4.16 4.375

^■*τnpp 4.016 4.014 4.015 2.402 2.402 2.402

V_o 21.313 21.318 21.3155 5.255 5.255 5.255 ι« 4.669 4.667 4.668 3.167 3.168 3.1675 ff 0.654 0.654 0.654 0.60 0.60 0.60

By multiplying the average results from the single string, one sun deployment, by a factor of four, the average results may be directly compared and the improvement achieved in the instant deployment can be calculated:

TABLE 2

Parameter Average. This invention Average, flat plate X4 Improvement

P„_Pp 65.07 39.97 63%

V_mpp 16.21 17.50 -7%*

I_mpp 4.02 2.40 67%

V_κ 21.32 21.02 1%

I„ 4.67 3.17 47% ff 0.65 0.60 9%

•The voltage appears to go down. However, this is attributable to the fact that in the deployment of the instant invention, electrical resistance is experienced through the interconnection of the four strings which is not reflected in the mathematical conversion of the one sun, single string results to one sun, four string results.

From these data, it can be seen that the power produced in the instant invention is 63% greater than without concentration. Since the theoretical concentration factor is 78%, this system is operating at about 80% of its theoretically possible maximum. In addition, it can be seen that the fill factor, ff, is increased by 9%, which represents a substantial increase in the efficiency of power production. The above data was generated using monocrystalline PV cells. Using edge defined film growth (EFG) PV cells, such as that produced by Deutch Aerospace-ASE Americas, this improvement is increased. These results, obtained under normal insolation (equivalent to high-noon conditions) are ideal for both the flat plate and deployment of the instant invention. Under lighting conditions where the light source is at an angle away from the normal, the wide acceptance angle of the concentrator of this invention continues to provide superior power production where the flat-plate deployment does not, as shown in Table 3.

TABLE 3

Time •Current (I_«) ^♦Voltage (V J % Increase

I,e v«

8:00 AM 1.62 5.22 2.30 1.02 0.70 5.10

8:30 AM 2.41 5,15 1.40 1.002 1.71 5.14

9:00 AM 3.19 5.10 1.49 1.01 2.13 5.04

9:30 AM 3.58 5.02 1.40 1.008 2.54 4.98

3:00 PM 3.79 4.78 1.45 1.01 2.61 4.69

3:30 PM 3.83 4.81 1.69 1.02 2.26 4.70

4:00 PM 3.34 4.85 1.78 1.01 1.87 4.76

4:30 PM 2.29 4.93 1.65 1.02 1.38 4.80

•Note: The top figure in each column represents data generated in the concentrator of this invention; the bottom figure represents data generated using a flat plate under 1 sun conditions. Two 9-cell strings were used, one as the flat plate reference string, and an identical string used in the concentrator of this invention.

In summary, a single element solar concentrator for photovoltaic, photochemical, and photothermal applications is disclosed. A single element concentrator is positioned to receive direct and diffused solar radiation and then transmit dispersed and focused radiation toward solar receivers 16 with optical characteristics of static deployment, isotropic irradiation, and operation from wide angle of incidence. Additionally, the single element can operate as a waste-heat sink radiator and a housing structure for the photovoltaic, photochemical, or photothermal receivers.

It will be appreciated from this description that the instant invention provides certain improvements over known solar converters such as that described in U.S.

Patent 3,232,795 which claimed a space-craft mounted (i.e. moving and tracking) solar energy converter comprising a plurality of light sensitive elements having a conversion efficiency characteristic which decreases with rising temperature, and a supporting matrix for said elements comprising a thermally conductive and emissive metal sheet upon selected spaced-apart surface areas of which said elements are mounted in light- receiving position having substantially full back sides thereof joined in surface-to- surface thermal transfer contact with the sheet, said sheet having frontally projecting individual wedge-like reflector corrugations occupying the respective regions between and immediately adjoining said elements, said corrugations being formed with sloping sides which gather and reflect light onto said elements and which have exposed front and back surfaces to radiate heat transferred thereto by conduction from said surface areas, the back sides of the sheet in such surface areas also being exposed to radiate heat, such that the instant solar converter is adapted to terrestrial operation in a non- moving, non-tracking deployment, the improvements comprising (a) the absence of space between the light sensitive elements; (b) non-tracking isotropic operation in a substantially east-west orientation during many hours of solar illumination as a result of the dimensions of the wedge-like reflector corrugations being larger than the dimensions of the light sensitive elements so as to allow for a wider angle of acceptance for the concentrator while the converter remains non-moving during its daily operation; (c) the provision of a plurality of apertures at the base or upper edge of the wedge-like reflector corrugations; (d) the angling of the wedge-like reflector corrugations from an angle of about 120° compared to the base at the bottom edge of the reflector to an angle of about 110° at the top edge of the reflector; and (e) the provision of a filter above the light sensitive elements, said filter rejecting photons having an energy below, and transmitting photons having an energy above, the bandgap of the light sensitive elements, such that the instant solar converter is adapted to efficient terrestrial operation in a non-moving, non-tracking deployment and is convectively cooled by ambient airflow.

It will therefore be readily understood by those persons skilled in the art that the present invention is susceptible of broad utility and application. Many embodiments and adaptations of the present invention other than those herein described, as well as many variations, modifications and equivalent arrangements will be apparent from or reasonably suggested by the present invention and the foregoing description thereof, without departing from the substance or scope of the present invention. Accordingly, while the present invention has been described herein in detail in relation to its preferred embodiment and its best mode, it is to be understood that this disclosure is only illustrative and exemplary of the present invention and is made merely for purposes of providing a full and enabling disclosure of the invention. The foregoing disclosure is not intended or to be construed to limit the present invention or otherwise to exclude any such other embodiments, adaptations, variations, modification and equivalent arrangements, the present invention being limited only by the claims appended hereto and the equivalents thereof

References

Brent, Charles R., U.S. Patent No. 4,217,881, issued August 19, 1980.

Citron, Jeffrey M., U.S. Patent No. 4,295,463, issued October 20, 1981.

Fitzsimmons, James W., U.S. Patent No. 4,789,408, issued December 6, 1988.

Gillette, Roger B., Howard E. Snyder, Ralph J. Tallent, U.S. Patent No. 3,232,795, issued February 1, 1966.

Schertz, William W., U.S. Patent No. 4,789,408, issued July 11, 1978.

Ule, Louis A., U.S. Patent No. 3,350,234, issued October 21, 1967.

Claims

1. A non-tracking, isotropic solar concentrator heat sink and housing for holding solar receivers comprising: (a) at least one sheet of solar reflective material structured so as to form at least one V-shaped trough, each said at least one V-shaped trough having two walls and a base, said base having two sides, each wall having an upper edge and a lower edge, and each trough having said base positioned between said lower edges of said two walls of said at least one trough; and (b) a solar receiver housing area located on one side of said base; wherein said walls of said solar receiver are extended a distance beyond the distance of the solar receiver on either end of the solar receivers such that the solar concentrator can accept solar irradiance and irradiate the receivers isotropically while the concentrator remains non-moving using an east- west orientation during its daily operation.

2. A non-tracking solar concentrator according to claim 1 wherein said at least two walls and said base a formed of a heat conducting material.

3. A non-tracking solar concentrator according to claim 2 wherein at least a portion of said at least two walls and said base is in contract with a structural member.

4. A non-tracking solar concentrator according to claim 2 wherein said heat conducting material is aluminum.

5. A non-tracking solar concentrator according to claim 1 wherein for each said at least one V-shaped trough said base and each said wall are joined at angle of 120°.

6. A static non-tracking, isotropic solar concentrator and housing for holding solar receiving comprising: (a) a static sheet of solar reflective material structured so as to form at least one V-shaped trough, each said at least one V-shaped trough having two walls and a base, said base having two sides, each wall having an upper edge and a lower edge, and each trough having said base positioned between said lower edges of said two walls of said at least one trough; and (b) a solar receiver housing area located on one side of said base; and (c) at lease one solar receiver in said housing area substantially covering said housing area, provided that said walls of said solar receiver are extended a distance beyond the distance of the solar receiver on either end of the solar receivers such that the solar concentrator can accept solar irradiance and irradiate the receivers isotropically while the concentrator remains non-moving using an east-west orientation during its daily operation.

7. The non-tracking, isotropic solar concentrator of claim 1 further comprising a plurality of apertures along the lower edge or upper edge of the walls.

8. A method of extending the non-tracking, isotropic solar concentrator of claim 1 which comprises overlapping the walls of the V-shaped trough or the upper edge of walls of successive units, and affixing each unit to a brace.

9. The non-tracking, isotropic solar concentrator of claim 1 wherein the lower edge of the walls are at an angle of about 120° to the base and the upper edge of the walls are at an angle of about 110° to the base.

10. The non-tracking, isotropic solar concentrator of claim 9 wherein the walls are bent into segments such that each successive segment is at a reduced angle from 120° to a final segment at 110° from the base.

11. The non-tracking isotropic solar concentrator of claim 1 wherein the solar receiver housing area houses a solar receiver comprising solar photovoltaic receiver cells below a filter which rejects photons having an energy below the bandgap of the photovoltaic receiver cells.

12. The non-tracking, isotropic solar concentrator of claim 1 wherein the at least one sheet of solar reflective material is the Everbrite™ material manufactured by Alcoa Aluminum Corporation.

13. An improved solar energy converter comprising a plurality of light sensitive elements having a conversion efficiency characteristic which decreases with rising temperature, and a supporting matrix for said elements comprising a thermally conductive and emissive metal sheet upon which said elements are mounted in light- receiving position having substantially full back sides thereof joined in surface-to- surface thermal transfer contact with the sheet, said sheet having frontally projecting individual wedge-like reflector corrugations occupying the respective regions between and immediately adjoining said elements, said corrugations being formed with sloping sides which gather and reflect light onto said elements and which have exposed front and back surfaces to radiate heat transferred thereto by conduction from said surface areas, the back sides of the sheet in such surface areas also being exposed to radiate heat, the improvement comprising the absence of space, between the light sensitive elements.

14. The improved solar energy converter of claim 13, the improvement further comprising non-tracking isotropic operation in a substantially east-west orientation during many hours of solar illumination as a result of the dimensions of the wedge- like reflector corrugations being larger than the dimensions of the light sensitive elements so as to allow for a wider angle of acceptance for the concentrator while the converter remains non-moving during its daily operation.

15. The improved solar energy converter of claim 14 wherein the improvement further comprises: (a) the provision of a plurality of apertures at the base or upper edge of the wedge-like reflector corrugations; (b) the angling of the wedge-like reflector corrugations from an angle of about 120° compared to the base at the bottom edge of the reflector to an angle of about 110° at the top edge of the reflector; and (c) the provision of a filter above the light sensitive elements, said filter rejecting photons having an energy below, and transmitting photons having an energy above, the bandgap of the light sensitive elements.

16. The improved solar energy converter of claim 13 wherein said light sensitive elements are edge defined film growth PV cells.

17. The improved solar energy converter of claim 16 wherein the edge defined film growth PV cells are produced by Deutch Aerospace-ASE Americas.

18. The non-tracking solar concentrator of claim 1 having a fill-factor of 0.65 or greater.