WO2013095120A1

WO2013095120A1 - Solar concentrator system

Info

Publication number: WO2013095120A1
Application number: PCT/NL2012/050888
Authority: WO
Inventors: Stephan KOOPMANS
Original assignee: SENTER TECHNUM
Current assignee: SENTER TECHNUM
Priority date: 2011-12-14
Filing date: 2012-12-14
Publication date: 2013-06-27
Anticipated expiration: 2014-06-14
Also published as: NL2007970C2

Abstract

The present invention is in the field of concentrating solar power technology. The invention relates to a solar concentrator system, to an apparatus for conversion of radiation comprising the solar concentrator system, to a construction element comprising the apparatus and to a click and fit modular building system comprising the apparatus.

Description

Solar concentrator system

FIELD OF THE INVENTION

The present invention is in the field of concentrat- ing solar power technology.

BACKGROUND TO THE INVENTION

The invention relates to a solar concentrator, to an apparatus for conversion of radiation comprising the solar concentrator, to a construction element comprising the appara- tus and to a click and fit modular building system comprising the apparatus, and a film comprising a solar concentrator.

A solar concentrator is a device for directing light onto a light harvesting surface of an apparatus for capturing, converting or distributing solar radiation such as of a photo- voltaic solar panel or of a solar thermal collector. The purpose of the solar concentrator is to increase the amount of light reaching the light harvesting surface. Typically solar concentrators work by focusing light e.g. with a mirror or lens .

The present invention was developed in the course of research into improved domestic photovoltaic (PV) cell based solar power systems. The invention will be elucidated in this context, but is not to be considered limited thereto.

Examples of solar concentrators, such as for use in combination with PV cells are known in the prior art.

Patent application WO 0074147 recites a holographic planar concentrator (HPC) for collecting and concentrating optical radiation. The holographic planar concentrator comprises a planar highly transparent plate and at least one multiplexed holographic optical film mounted on a surface thereof. At least one solar energy-collecting device, such as a photovoltaic cell, is mounted beneath said holographic optical film. The optical radiation is guided within the plate by the holographic film and total internal reflection to be concen- trated on the solar energy collecting device.

Disadvantages are: the need for a relatively complex design to avoid recoupling; recording of the plurality of dif- fractive structures must be tailored to the intended orientation of the holographic planar concentrator to solar energy; many holographic films do not have a long working life due to the chemicals and polymers used in their manufacture, and; many of the chemicals used for manufacture of holographic gratings are not environmentally friendly.

Although the invention of WO 0074147 is certainly useful for the intended purpose, improvements there over are sought; the present invention represents such an improvement.

The prior art comprises further more or less relevant solar concentrators:

WO 89/05520 recites a solar cell module comprising several bilaterally active solar cells arranged on an array of several parallel channel-shaped reflectors. The reflectors deflect part of the solar radiation incident alongside the solar cells to the lower side of the solar cells. The channel-shaped reflectors have a semi-circular cross-section. The solar cells are rectangular and their width corresponds to the diameter of the semicircular reflectors. The solar cells project by half their length beyond the corresponding reflector openings.

FR 2 342 558 recites a device for converting solar energy into electrical energy comprising a substantially planar semiconducting PV cell and a concave optical reflector associated with the cell. Two principal faces of the cell that oppose each other are photosensitive; the cell is situated substantially in the plane of the opening of the optical re- flector in a lateral position, the incident light being separated into a first fraction directed to a first photosensitive surface of the cell, and a second fraction, at least partially directed by the reflector onto a second photosensitive surface of the cell opposite to the first.

WO 2009/135892 relates to a device used for concentrating incident light, comprising at least one statically mounted channel or trough-shaped mirror component that allows the incident light to be deflected onto at least one photovoltaic PV absorbing element.

EP0877213 (A2) recites a concavely formed reflector being arranged beneath the at least one heat collector, the width of which is essentially greater than that of the heat collector itself. The incoming light and heat radiation arrives either on the front side of the at least one heat col- lector or is reflected on to its rear side by the reflector. At least a large part of the rear side of the at least one heat collector is formed with photovoltaic components, which by means of the concavely formed reflector are fed with bun- died light energy. The at least one heat collector is equal in width to a sixth to a half of the width of the reflector.

EP0614058 (A2) recites a device for collecting heat energy, in particular solar energy, namely a heat collector, consisting of a frame-like structure, on which a plurality of collector pipes being rotatable mounted thereon.

A disadvantage of the above two systems is that it comprises rotating parts, which amongst others makes it vulnerable .

FR2921758 recites a device for the capture of solar radiation, comprising a base and a cover transparent to solar radiation and fixed to the base, the base and lid defining between them at least one cavity, and it comprises, in said cavity, at least one solar collector comprising at least one photovoltaic module having a surface sensitive to sunlight and at least one reflecting surface for reflecting towards the sensitive surface of the solar radiation sensor through the cover .

EP2383798 (Al) recites a solar cell including a front panel, photovoltaic generating parts located on a back side of the front panel and arranged in an array direction at a designated pitch; and a reflective part that reflects sunlight toward the back surface of the photovoltaic generating parts. The reflective part includes a reflective panel and a back panel .

DE102011050812 (Al) recites an arrangement having a

V-shaped retaining element holding a photovoltaic absorber unit i.e. solar cell, for irradiation with direct and/or reflected sunlight. The retaining element is made of metallic material i.e. aluminium, and includes a compensating geometry for compensation of thermal expansion.

EP2234177 (Al) recites a solar cell module which can collect solar light to a solar cell, while reducing accumulation of dusts and particles. The solar cell module is provided with a plurality of bifacial solar cells. The solar cells are coated together with a sealing film formed of a sealing resin material. A front surface side transparent board is bonded on the upper surface in the gravity direction, i.e., the front surface of the sealing film. On the front surface side of the front surface side transparent board, a lenticular lens is arranged for collecting solar light to a solar cell by refracting solar light entered from the front surface side of the solar cell module. On the lower surface in the gravity direction, i.e., the rear surface, of the sealing film, a rear sur- face side transparent board is bonded. On the rear surface side of the rear surface side transparent board, an uneven reflection film is arranged for reflecting solar light entered from the front surface side of the solar cell module and collecting the light to the solar cell.

The above system is somewhat complex from nature, e.g. in terms of manufacturing and construction, and comprises many different elements. It also comprises a non-optimal reflecting film, in terms of e.g. efficiency. Further it can only be used in one orientation.

For many of the above systems also inherently the light entering is partly reflected at an inner face of the covering surface, leading to a loss in efficiency. Further light that has entered can leave the system, e.g. through a cover thereof. Also not all or almost all of the light is di- rected towards at least one internal plane. The structures are further relatively heavy, and are therefor unsuited for many roofs and the like.

Common disadvantages of many of the solar concentrator systems of the prior art are their sensitivity to the relative angle of incident light, often necessitating the incorporation of complex and expensive sun-tracking mechanisms; their poor performance in diffuse light conditions, and; the lack of sufficient cooling means: temperatures greater than 90 degrees Celsius are detrimental to the performance of most PV cells.

SUMMARY OF THE INVENTION

It is an object of the invention to provide an improved and/or alternative to the solar concentrators of the prior art . The invention primarily relates to a solar concentrator according to claim 1. The solar concentrator is static, in that it does not comprise any moving/rotating part. As such the present system is robust, applicable on most surfaces, and not vulnerable. Further the transparent element is flat, thereby allowing optimal entrance of light.

The first transparent element has multiple functions: it provides a "window" through which light may be transmitted into the internal space of the concentrator; it provides a to- tal internal reflection surface for directing light; it serves to partially enclose the internal space, and; it provides protection to any components, such as a PV cell, incorporated in the internal space.

The first transparent element is comprised of a transparent material that transmits light with a wavelength at least in the range, and preferably at least spanning the range of 500-1000 nm, preferably 400-1100 nm, most preferable 360- 1200 nm. Furthermore, the transparent material preferably has a transmittance of at least 70 % per 3.2 mm of thickness in the 400 to 1100 nm range of the electromagnetic spectrum, preferably 80 %, more preferably 90 % or more than 91.5 %.

The first transparent element preferably further comprises a protective layer at a surface thereof, such as at an outer surface. The protective layer preferably at least par- tially inhibits the passage of oxygen and/or water.

The one or more surfaces comprising one or more mirrors is provided both to partially enclose the internal space and to provide a reflection surface.

In an exemplary embodiment, the one or more mirror (s) of the one or more surface (s) are provided as a layer on the one or more surfaces, such as a metal layer, such as a layer of aluminium or silver.

The one or more surface (s) and the first transparent element are arranged to direct light, transmitted through the first transparent element, onto at least the first internal plane by reflection at the one or more mirror (s) of the one or more surface (s) and/or by total internal reflection at a surface of the first transparent element.

In an exemplary embodiment, the one or more sur- face(s) and the first transparent element are arranged to direct light, transmitted through the first transparent element, onto front and rear surfaces of the first internal plane.

In order to achieve concentration of light incident on the solar concentrator, the first area of the first transparent element is larger than the second area of the first internal plane.

The solar concentrator is particularly suitable for use in locations where diffuse weather conditions are predomi- nant, such as in northern Europe.

The invention further relates to an apparatus for conversion of radiation comprising the solar concentrator system, to a construction element comprising the apparatus, to a click and fit modular building system comprising the appara- tus, and to a film.

DETAILED DESCRIPTION OF THE INVENTION

In a first aspect, the invention relates to a solar concentrator according to claim 1.

In an exemplary embodiment, the first area is ≥ 1.2 second area, preferably the first area is ≥ 1.33 second area, more preferably the first area is ≥ 1.5 second area, even more preferably the first area is ≥ 2.0 second area, such as the first area is ≥ 2.4 second area.

In an exemplary embodiment, the one or more segments are the same and comprise at least a first virtual plane of symmetry substantially perpendicular to the first transparent element, and optionally a second virtual plane of symmetry substantially perpendicular to the first transparent element and substantially perpendicular to the first virtual plane of symmetry.

In an exemplary embodiment, the system comprises two or more repetitive segments, the segments being placed in a 2D-plane .

Each segment may comprise an isolated internal space, or the internal space may extend over multiple segments.

In an exemplary embodiment the segments concentrate light cooperatively.

In an exemplary embodiment, the system comprises one or more transparent materials substantially filling the inter- nal space, wherein a first refractive index of the first transparent element and a second refractive index of the one or more transparent materials are substantially the same, such as wherein the first refractive index is between 1.2 and 1.9, preferably between 1.3 and 1.8, more preferably between 1.3 and 1.7, most preferably between 1.4 and 1.6. and wherein the second refractive index is 0-0.5 larger or smaller than the first refractive index, preferably 0-0.25 larger or smaller, more preferably 0-0.1 larger or smaller, such as the first and second refractive indices are substantially the same.

It is advantageous for the first and second refractive indices to be substantially the same to limit refraction of light entering the first transparent element through the one or more transparent materials. Refraction of light enter- ing the first transparent element is undesirable for the efficiency of the system. Total internal reflection only occurs at a boundary between a first medium and a second medium if light is passing from the first medium to the second medium wherein the refractive index of the second medium is lower than the refractive index of the first medium.

The one or more transparent materials are preferably one or more of a group comprising: air, nitrogen, argon, water, ethylene glycol, propylene glycol, glass, PMMA, polycarbonate .

In an exemplary embodiment, the one or more surface (s) comprise (s) one or more of (i) a straight surface and (ii) a curved surface, wherein the curved surface preferably is a pseudo-circular surface, and wherein the straight surface is at a mirror angle β with an imaginary plane perpendicular to the plate, wherein the mirror angle preferably is from (90- 25)° -(90-50)°, more preferably from (90-30)° -(90-45)°, such as from (90-35)° -(90-40)°.

In an exemplary embodiment, a first end point of the one or more internal planes is located substantially centrally in a segment, and/or wherein optionally a second endpoint of the one or more internal planes is located substantially in a centre of the curved surface.

In an exemplary embodiment, the first transparent plate and the surface are made from a material selected from glass, PMMA, polycarbonate; preferably PMMA.

PMMA has a number of properties that make its use particularly advantageous: it has a broad transmission spectrum covering the most preferred range of the invention; it is amenable to moulding and extruding, facilitating manufacture of the solar concentrator, it is relatively inexpensive, robust, durable and resistant to degradation by UV light or by oxidation .

Particular advantages of the first aspect of the in- vention will become evident with reference to the drawings.

The solar concentrator is designed to direct a maximum amount of external radiation from a wide range of angles onto the first internal plane and is suitable both for use in direct and diffuse light conditions. This is achieved by trap- ping radiation inside the internal space through internal reflection at the boundaries of the solar concentrator. At the one or more surfaces, this is achieved by reflection at the one or more mirrors; at the first transparent surface, this is achieved by total internal reflection/optical boundary reflec- tion. The positions and geometries of the one or more surfaces comprising one or more mirrors, the first transparent surface and the internal plane are related to maximise concentration of light onto the internal plane.

In a second aspect, the invention relates to an appa- ratus for conversion of radiation, according to claim 9.

The means for converting radiation into heat and/or electricity is preferably embodied as one or more photovoltaic solar cell(s) comprising the PV layer, and/or one or more solar thermal device (s), preferably wherein the photovoltaic so- lar cell(s) and/or solar thermal device (s) constitute at least a portion of the first internal surface of the solar concentrator .

In an exemplary embodiment, a liquid absorbs energy from the solar concentrator of the apparatus. A person of skill in the art can envisage many ways in which this could be achieved, such as for example by providing pipes such as copper pipes at, or in a surface of the solar concentrator through which the liquid is passed. In an exemplary embodiment, the PV-layer is selected from the group comprising a III-V layer, a single junction, a multiple junction, such as a 3-junction and a 4-junction, a concentrator layer, a high efficiency layer, a doped Si- layer, and combinations thereof, and wherein the PV-layer preferably is a double PV-layer and/or a bifacial PV-layer.

In an example the PV-layer is in a horizontal orientation, parallel to the present first transparent element. Such is less preferred as exact positioning is difficult, leading to a loss of efficiency. Also interconnecting PV- elements is complex and typically vulnerable.

In an example the PV-layer is in a vertical orientation, perpendicular to the first transparent element, or in orientation having an angle with respect to the first transparent element, such as under an angle of 20-70°, e.g. 30-60°, or 40-50°, or 45°. Therewith it is possible to use an electrical conducting reflecting surface, providing electrical connection between PV-elements, e.g. by providing serial and/or parallel strings thereof. Such provides e.g. im- proved electrical contact, reduced resistance, lower losses, a huge amount of variation in design, no need for electrical tracks, higher yield, and a reduction of a risk of interruption (breakage) thereof. Further the conducting surface provides for cooling, e.g. a reduction in temperature,

therewith e.g. improving yield of PV-elements. The above PV- elements are situated on the first internal plane. Further the system can be manufactured in a roll-to-roll (R2R) process. In a simplified embodiment the present solar concentrator comprises an optically coupled transparent and geometri- cally triangular longitudinal system, comprising three sides, wherein each side performs a unique and complementary function: a first side collects radiation and internally reflects radiation, a second side is an internal radiation reflecting side and optional electrical conducting side, and a third side is a radiation absorption side, such as a PV- element. The three sides are optically coupled elements exchanging internal radiation, until it is typically converted. At least one side of the second and third side men- tioned above may also provide cooling and/or may transfer heat .

In a further exemplary embodiment the mirror surface comprises an Al-foil. In an alternative the mirror surface is semi-transparent.

In a further example air-cooling is provided at a bottom side of the mirror surface.

It is noted that the present system is capable of redirecting most of the light entered towards the first in- ternal plane, directly or indirectly. It has been established that depending on the relative position of the sun more than 95% of the light entered is directed towards the first internal plane, typically more than 98%, such as more than 95%. None of the prior art systems achieve such re- suits .

Also the present system may be (relatively) thin and light, having e.g. a total thickness of 0.2-10 mm, typically 1-5 mm, preferably 2-3 mm. In view of present manufac- turability a not too thin system is preferred. In view of costs a thin system is preferred. A further advantage is that the above thin material can be cut and processed without loss of efficiency and without jeopardizing functionality.

In an exemplary embodiment, the apparatus is in the form of one or more units, preferably with a unit length of

5-500 cm, more preferably 50-100 cm, in the form of a continuous or semi-continuous sheet, wherein the one or more units can be removable attached to each other.

In a third aspect, the invention relates to a con- struction element, such as a roofing, cladding, window, lighting, artistic application, comprising at least one apparatus, such as two or three, for conversion of radiation according to the second aspect of the invention and its exemplary embodiments .

In an exemplary embodiment, the construction element comprises one ore more connectors for connecting the apparatus selected from the group consisting of a two way connector, a three way connector and a four way connector, wherein the connectors are preferably arranged to allow side to side connec- tion with or without offset, wherein the connector is selected from the group of electrical connector and fluid connector.

In a fourth aspect, the invention relates to a click and fit modular building system comprising at least one appa- ratus according to the second aspect of the invention and its exemplary embodiments and/or one or more construction elements according to the third aspect of the invention and its exemplary embodiment and/or one or more connectors for connecting the at least one apparatus and/or construction element.

In a fifth aspect, the invention relates to a film or sheet comprising an array of concentrator or apparatus according to the first en the second aspect of the invention and its exemplary embodiments.

The invention is further detailed by the accompanying figures, which are exemplary and explanatory of nature and are not limiting the scope of the invention. To the person skilled in the art it may be clear that many variants, being obvious or not, may conceivably fall within the scope of protection, defined by the present claims.

SUMMARY OF THE DRAWINGS

Figure 1 shows a first exemplary embodiment of the solar concentrator of the invention;

Figure 2 shows a second exemplary embodiment of a segment of the solar concentrator of the invention;

Figures 2(a) and 2(b) show calculated absorption rate results for the solar concentrator of Figure 2;

Figures 3 and 4 are a representation of the first and second exemplary embodiment of the solar concentrator of the invention in use, respectively;

Figure 5 and 6 are a first and second view of an exemplary embodiment of the apparatus of the invention, respectively;

Figure 7 is an exemplary embodiment of the construction element of the invention;

Figure 8 is an exemplary embodiment of a module of the click-and-fit modular building system of the invention;

Figure 9 is an exemplary embodiment of an arrangement of modules of the click-and-fit modular building system of the invention . Figures 10-12 show exemplary embodiments.

DESCRIPTION OF THE DRAWINGS

Where in the Figures, the same reference numerals or characters are used, these reference numerals or characters refer to the same parts.

Figures 1 and 2 show first and second exemplary embodiments respectively of the solar concentrator 1 of the invention comprising two segments 2a, 2b wherein each segment 2a, 2b comprises: a first transparent element 3 having a first area A; one or more surface (s) 4, substantially opposing the first transparent element 3, comprising one or more mirror (s) 5 for redirecting light, the one or more surface (s) 4 and the first transparent element 3 being sides of an internal space 6, wherein the one or more surface (s) 4 and the first trans- parent element 3 are arranged to direct light to at least a first internal plane 7, having a second area B, inside said internal space 6. The first area A is larger than the second area B, preferably first area A is at least a factor of 1.1 larger than area B.

In a preferred exemplary embodiment, the first area A is at least a factor of 1.2 larger than the second area B, preferably the first area A is at least a factor of 1.33 larger than the second area B, more preferably the first area A is at least a factor of 1.5 larger than the second area B, even more preferably the first area A is a factor of at least 2.0 larger than the second area B, such as the first area A is at least a factor of 2.4 larger than the second area B.

The one or more segments 2a, 2b are the same and preferably comprise at least a first plane of symmetry X substan- tially perpendicular to the first transparent element 3, and optionally a second plane of symmetry Y substantially perpendicular to the first transparent element 3 and substantially perpendicular to the first plane of symmetry X, i.e. in the plane of the page of the drawing of Figures 1 and 2.

Figures 1 and 2 show a solar concentrator comprising two repetitive segments 2a, 2b placed in a 2D plane, i.e. arranged in a repetitive manner with their long axes aligned such that they are parallel and with their extremities level. Whilst only two segments 2a, 2b are shown, in practice, the so- lar concentrator 1 of the invention may comprise many more than two segments 2a, 2b arranged in this manner. Suitable numbers are dependent on the application, the dimensions of the system 1 and the space available for the installation.

Each extremity of the segments (2a, 2b) is preferably provided with an additional mirrored surface arranged to reflect light having passed along the segment to either of its ends, at least partially back along the length of the segment.

The internal space 6 comprises one or more transpar- ent materials 8, preferably one, substantially filling i.e. for all extents and purposes, filling, the internal space 6, wherein a first refractive index of the first transparent element 3 and a second refractive index of the one or more transparent materials 8 are substantially the same, such as wherein the first refractive index is between 1.2 and 1.9, preferably between 1.3 and 1.8, more preferably between 1.3 and 1.7, most preferably between 1.4 and 1.6 and wherein the second refractive index is 0-0.5 larger or smaller than the first refractive index, preferably 0-0.25 larger or smaller, more prefera- bly 0-0.1 larger or smaller, such as substantially the first and second refractive index are substantially the same.

The one or more transparent materials 8 are preferably one or more of a group comprising: air, nitrogen, argon, water, ethylene glycol, propylene glycol, glass, PMME and polycarbonate; preferably PMME.

In Figure 1, the one or more surface (s) 4 are shown to comprise two straight surfaces 4 'a, 4'b, each straight surface is at a mirror angle β with an imaginary plane Z perpendicular to the first transparent plate, wherein the mirror an- gle preferably is from (90-25)° -(90-50)°, more preferably from (90-30)° -(90-45)°, such as from (90-35)° -(90-40)°. An angle of about 45 degrees is shown. The two straight surfaces 4 'a, 4'b may be two portions of the surface 4, or two connected separate surfaces; they are preferably a single surface provided with a bend at a mid point of the surface for ease of manufacture .

In Figure 2, the one or more surface (s) are shown to comprise (i) a straight surface S and (ii) a curved surface C, wherein the curved surface C preferably is a pseudo-circular, and wherein the straight surface S is at a mirror angle β with an imaginary plane perpendicular to the plate as in Figure 1, wherein the mirror angle β preferably is from (90-25)° -(90- 50)°, more preferably from (90-30)° -(90-45)°, such as from (90-35) ° - (90-40) ° .

With regards to Figures 1 and 2, and for clarity, it should be noted that β = (90-α)

It is advantageous to provide a mirror angle β within the ranges stated to ensure the efficiency of the solar con- centrator in diffuse light conditions. Figures 2(a) and 2(b) show calculated absorption rate results for the solar concentrator 1 shown in Figure 2, assuming the first internal surface 7 is an absorbing surface, such as a photovoltaic layer of a PV cell, under direct and indirect light conditions re- spectively, for various mirror angles β.

Both Figures 1 and 2 show only a single internal plane centrally placed in the segment 2a, 2b i.e. the first internal plane 7. The orientation of the internal plane is dependent on the shape of the one or more surfaces 4. In Figure 1, the internal plane 7 is perpendicular to the first transparent element; the internal plane is preferably fixed at at least one extremity, preferably to the first transparent element 3 and/or the one or more surfaces 4. In Figure 2, the internal plane 7 is parallel to the first transparent element 3. The internal plane 7 is shown separate from the first transparent element, but for ease of manufacture, is preferably mounted thereto.

The first transparent plate 3 and the surface 4 are preferably made from a material selected from glass, PMMA, polycarbonate. PMMA, poly (methyl methacrylate ) is particularly preferred since it can readily be formed into a range of shapes by techniques such as moulding and extrusion; it is chemically stable e.g. not prone to oxidation or damage by UV; it is robust and hard wearing and has favourable optical prop- erties as outlined in the detailed description of the invention.

Figures 3 and 4 are representations of light paths within the solar concentrators 1 of Figures 1 and 2 when exposed to a source of light: in this example, direct light L, such as sunlight.

Figure 5 shows a first view of an exemplary embodiment of the apparatus 1' of the invention; Figure 6 is a second view showing a cross-section through the line A-A. The ap- paratus 1' is for the conversion of radiation and comprises the solar concentrator 1 of the invention, embodied in this example as the solar concentrator 1 of Figure 2, and a means for converting radiation into heat and/or into electricity, embodied as a bi-facial or back-to-back mono-facial PV element 2'. The apparatus is fixed or fixable on a surface (not shown), and further comprises an elastic weather seal 3', an elastic connection adapter 4' for coupling to additional apparatus and to form an electrical and/or fluid connection from one apparatus unit 1' to another, an edge sealing strip 5' to seal the internal unit volume from the outside, a transparent top plate 6' which serves to protect the elements thereunder, transparent elastic sealing and adhesion 7' to seal the PV element 2' and the solar concentrator 1, a coolant or liquid for absorbing energy 8' which flows through the space between the solar concentrator 1 and a bottom plate 9'; the structural bottom plate 9' protects the solar concentrator 1, to seal the fluidic area from the outside and to form a structural support of the apparatus 1 ' .

The mirrored surface 10' is also indicated. Optionally, the solar concentrator 1 may contain channels through which a coolant can remove excess thermal energy. Coolant may also flow through the space which is formed between the solar concentrator 1 and the bottom plate 9 ' .

The apparatus 1' is built up as a sandwich construction from a transparent top plate 6', in-line and spaced apart strips of Bi-facial or back-to-back mono-facial PV elements 2' and the solar concentrator 1 as described above. These components are tightly sealed together by a transparent and

flexible adhesive 7' such as EVA (ethylene vinyl acetate) or similar. As regards the transmission of radiation, the sandwich construction behaves as single transparent component with high optical breaking index and low optical transmission losses. In essence, the flow of radiation in the construction behaves as indicated in Figure 2 above and is dependent on the radiation input angle and mirror lens geometry. The bottom surface of PV material will be targeted by redirected

irradiation only; the top surface of PV material will be tar- geted by both indirect and direct irradiation.

The materials from which each component of both the solar concentrator 1 and the apparatus 1 ' are constructed are chosen taking into account the relative extents to which they expand or contract as a function of temperature in order to ensure that they do not become damaged as a result of differential expansion or contraction of the various parts during normal use.

The PV-layer of the PV element is selected from the group comprising a III-V layer, a single junction, a multi- pie junction, such as a 3-junction and a 4-junction, a concentrator layer, a high efficiency layer, a doped Si-layer, and combinations thereof, and wherein the PV-layer preferably is a double PV-layer and/or a bifacial PV-layer.

The apparatus 1' is in the form of one or more units 11', preferably with a unit length of 5-500 cm, more preferably 50-100 cm; the one or more units 11' can be removable attached to each other using the elastic connection adapter 4'.

Figure 7 shows construction element 1'', such as for a roofing, cladding, window, lighting, artistic application, comprising multiple apparatus 1' for conversion of radiation.

The construction elements 1'' can be applied as structural components for roofing, cladding and walling purposes. It is suitable to replace- or to integrate with traditional roof tiled areas, flat roof areas or pre-manufactured building panels, light transmitting surface such as used for windows and greenhouses, sound absorbing walls such as applied for traffic noise protection, external walls such as used for building works or appliances such as refrigerators.

The construction elements further comprise one ore more connectors 2'' as shown in Figure 8, for connecting the apparatus 1' selected from the group consisting of a two way connector, a three way connector and a four way connector, wherein the connectors are arranged to allow side to side connection with offset as shown in Figure 9, or without offset, wherein the connector is selected from the group of electrical connector and fluidum connector.

Typically assemblies of solar panels of the prior art suffer the disadvantage that if one of the panels is shaded, the assembly no longer functions, much the same as old- fashioned Christmas tree light stopped functioning when one bulb was blown or removed. By providing each construction element 1'' with two connectors 2 ' ' on each side and staggering the construction elements as shown in Figure 9, this problem is overcome since there is more than one way of completing an electrical circuit comprising the construction elements 1''.

In figure 10 an asymmetrical layout is shown having alternating reflecting (4) and PV-surfaces (7), the reflecting surface interconnecting the PV-surfaces, being optimal when oriented south (or north) at noon.

In figure 11 two reflecting surfaces (4) are alternates with two PV-surfaces (7) .

In figure 12 a symmetrical layout is shown, comparable to figure 10, having no external losses and optimal performance under any orientation.

Claims

1. A static solar concentrator (1) comprising one or more segments (2), each segment (2) comprising:

a first transparent element (3) having a first area (A), the transparent element being substantially flat;

one or more surface(s) (4), substantially opposing the first transparent element (3), comprising one or more mir- ror(s) (5) for redirecting light,

the one or more surface (s) (4) and the first transparent element (3) being sides of an internal space (6),

wherein the one or more surface (s) (4) and the first transparent element (3) are arranged to direct light to at least a first internal plane (7), having a second area (B) , inside said internal space (6),

wherein the first area (A) is ≥ 1.1 second area (B) .

2. A solar concentrator (1) according to claim 1, wherein the one or more segments (2) are the same and comprise at least a first virtual plane of symmetry (X) substantially perpendicular to the first transparent element (3), and optionally a second virtual plane of symmetry (Y) substantially perpendicular to the first transparent element (3) and substantially perpendicular to the first virtual plane of symmetry (X) .

3. A solar concentrator (1) according to claim 1 or 2, wherein the solar concentrator (1) comprises two or more repetitive segments (2a, 2b), the segments (2) being placed in a 2D-plane.

4. A solar concentrator (1) according to one or more of the preceding claims, comprising one or more transparent materials (8) substantially filling the internal space (6), wherein a first refractive index of the first transparent element (3) and a second refractive index of the one or more transparent materials (8) are substantially the same, such as wherein the first refractive index is between 1.2 and 1.9, preferably between 1.3 and 1.8, more preferably between 1.3 and 1.7, most preferably between 1.4 and 1.6. and wherein the second refractive index is 0-0.5 larger or smaller than the first refractive index, preferably 0-0.25 larger or smaller, more 0-0.1 larger or smaller, such as the first and second refractive indices are substantially the same.

5. A solar concentrator (1) according to one or more of the preceding claims, wherein the one or more surface (s)

(4) comprise (s) one or more of (i) a straight surface (S) and (ii) a curved surface (C) , wherein the curved surface (C) preferably is a pseudo-circular or pseudo elliptical-surface, and wherein the straight surface (S) is at a mirror angle β with an imaginary plane perpendicular to the plate, wherein the mirror angle preferably is from (90-25)° -(90-50)°, more preferably from (90-30)° -(90-45)°, such as from (90-35)° - (90-40) ° .

6. A solar concentrator (1) according to one or more of the preceding claims, wherein the first area (A) is ≥ 1.2 second area (B) , preferably wherein the first area (A) is ≥ 1.33 second area (B) , more preferably wherein the first area (A) is ≥ 1.5 second area (B) , even more preferably wherein the first area (A) is ≥ 2.0 second area (B) , such as wherein the first area (A) is ≥ 2.4 second area (B) .

7. A solar concentrator (1) according to one or more of the preceding claims, wherein a first end point of the one or more internal planes (7) is located substantially centrally in a segment (2), and/or wherein optionally a second endpoint of the one or more internal planes is located substantially in a centre of the curved surface (C) .

8. A solar concentrator (1) according to one or more of the preceding claims, wherein the first transparent plate (3), the surface (4) and the first transparent material (8) are made from a material selected from glass, PMMA, polycarbonate, preferably PMMA.

9. An apparatus (1') for conversion of radiation, comprising a solar concentrator (1) according to one or more of the preceding claims, and a means for converting radiation into heat and/or into electricity (2'), wherein the apparatus is fixed or fixable on a surface, and

wherein the apparatus optionally comprises one or more of a system for energy transport (a), a transparent protection (b) , an encasement system (c) preferably comprising one or more of a cleaning system, such as a lens cleaning system, a sealing for the encasement, fixing means for the encasement system, and a support system, an energy storage system (e) preferably selected from a storage system for heat and a storage system for electricity, an energy converter (f) selected from the group of a pressure to electricity converter, a heater, a process heater, and a central heating system, an energy management system (g) , a PV layer (h) which layer is preferably applied to a surface of the first internal plane and/or which PV-layer is incorporated in a separate element, an absorber (i), a buffer system (j), and a rotator (k) .

10. An apparatus (1') for conversion of radiation according to claim 9, wherein a liquid (8') absorbs energy from the solar concentrator (1) .

11. An apparatus (1') for conversion of radiation according to claims 9 or 10,

wherein the means for converting radiation into heat and/or electricity (2') is embodied as one or more photovoltaic solar cell(s) comprising the PV layer, and/or one or more solar thermal device (s), and/or

wherein the PV-layer is selected from the group comprising a III-V layer, a single junction, a multiple junction, such as a 3-junction and a 4-junction, a concentrator layer, a high efficiency layer, a doped Si-layer, and combinations thereof, and wherein the PV-layer preferably is a double PV-layer and/or a bifacial PV-layer.

12. An apparatus (1') for conversion of radiation according to one or more of claim 9-11, in the form of one or more units, preferably with a unit length of 5-500 cm, more preferably 50-100 cm, in the form of a continuous or semi- continuous sheet, wherein the one or more units can be removable attached to each other.

13. A construction element {!''), such as a roofing, cladding, window, lighting, artistic application, comprising at least one apparatus, such as two or three, for conversion of radiation according to one or more of claims 9-12,

preferably comprising one ore more connectors (2'') for connecting the apparatus of any of claims 1-12 selected from the group consisting of a two way connector, a three way connector and a four way connector, wherein the connectors are preferably arranged to allow side to side connection with or without offset, wherein the connector is selected from the group of electrical connector and fluidum connector.

14. A click and fit modular building system comprising at least one apparatus according to one or more of claims 9-12 and/or one or more construction elements according to any of claim 13 and/or one or more connectors for connecting the at least one apparatus and/or construction element.

15. A film or sheet comprising an array of apparatus according to one or more of claims 9-12 and/or one or more solar concentrators (1) according to one or more of claims 1-8 and/or one or more construction elements according to claim

13.