Patent Application
20240247447
This invention relates to modular flooring units which incorporate solar panels for generating electrical power when subject to sunlight, and in particular to pavers which incorporate solar panels and which can be used in areas subject to pedestrian and/or vehicle loading.
Domestic solar power technology generally uses photovoltaic (PV) cells and is limited to rooftops and spaces where no access is normally required for other purposes. On a commercial scale, there exist a number of photovoltaic products suitable for mounting on sloping or flat roofs. PV tiles are known for use in roof construction.
Some attempts have been made to provide solar power devices for trafficable surfaces. US2005/0199282 discloses a roadway panel which has a solar energy collector beneath a layer of translucent and protective material which can withstand pedestrian and vehicular traffic loading and has sufficient friction in its upper surface to allow passage of pedestrians and vehicles without slippage. The roadway panel can be modularly connected to other similar panels. However energy harvest is reduced as horizontal panels receive limited direct sunlight, and hence operate at reduced efficiency. Furthermore the panel requires a compromise between toughness and translucence. US2010/0263296 discloses a flooring module with a load bearing floor on one surface and a photovoltaic cell on an opposite surface. The module can function either as a floor in a first position when the floor surface is uppermost or as an electrical generator in the second position when the photovoltaic cell is uppermost. However the panel is not capable of serving as both a load bearing floor and an electrical generator in the same position.
It is an object of the invention to provide a solar paving module and a paving construction utilising solar paving module that overcome one or more of the above disadvantages.
According to a first aspect of the present invention there is provided a solar paving module comprising:
The one or more ground plates may extend beyond the frame.
A portion of the heat sink, for example, one or more ground plates, may extend beyond the frame, for example, beyond the base of the frame. For example, a portion of the ground plate may be disposed within the frame, and a portion may extend beyond the plane of the base of the frame, optionally so that the extending portion can extend below the frame. This permits the extending portion to exchange heat with a substrate outside the frame, e.g. the ground or a railway sleeper for example.
The heat sink plate may be substantially parallel to the planar upper surface of the light transmitting surface screen and the one or more ground plates may extend substantially perpendicular to the heat sink plate.
Optionally two ground plates are provided and the extending portions of the ground plates may be connected (or optionally integrally formed) with the heat sink plate in a C-shaped arrangement, with spaced apart portions of the heat sink plate connected to or integrally formed with respective ground plates extending therefrom.
The heat sink plate and the one or more ground plates may be a single folded plate of heat conducting material. The material may be metallic or non-metallic, or a mixture thereof. Optionally, the single folded plate may be of steel, aluminium or an alloy thereof.
Alternatively the heat sink plate and/or the one or more ground plates may comprise one or more metal mesh panels, for example steel mesh. The heat sink plate which is substantially parallel to the planar upper surface may comprise a metal mesh panel, for example steel mesh, and the one or more ground plates which extend substantially perpendicular to the heat sink plate may each comprise an upper metal mesh panel portion and a lower plate portion.
The heat sink plate and the one or more ground plates may be integrally formed as a single piece.
The one or more ground plates may be two ground plates, and each of the ground plates may depend from sides of the heat sink plate.
The single piece may be C-shaped or omega-shaped when viewed in cross-section.
The heat sink may comprise a shaft, the shaft extending perpendicularly from the heat sink plate towards the power generating element.
The power generating element may comprise one or more elements of monocrystalline, polycrystalline, amorphous, single-junction, multi-junction, silicon-based, cadmium telluride based, quantum dots-based, and concentrated photovoltaic elements.
The frame may enclose the power generating element and at least a portion or the entirety of the screen, wherein an underside of the frame comprises a first interlocking member arranged to interlock with a second interlocking member provided on an upper surface of the heat sink plate.
The first interlocking member is arranged to releasably interlock with the second interlocking member.
The electrical connector may be provided on an underside of the heat sink plate, wherein the first and second interlocking members are arranged such that when they are interlocked the power generating element is electrically connected to the electrical connector, wherein the first and second interlocking members are arranged such that when they are not interlocked the power generating element is not electrically connected to the electrical connector.
The first interlocking member may be a recess provided on the underside of the frame and the second interlocking member may be a projection provided on the upper surface of the heat sink plate, which is receivable in the recess, wherein the recess and projection are arranged such that the power generating element becomes electrically connected to the electrical connection when the projection is received inside the recess.
The light transmitting surface screen may be releasably attached to the frame by one of a threaded fastener arrangement and a snap fit arrangement.
The power generating element may be provided on top of a thermally conductive layer, which comprises a metallic material.
A support layer may be provided intermediate the thermally conductive layer and the power generating element. The support layer may comprise silicone and optionally an additive for improving the thermal conductivity of the support layer.
The power generating element, support layer and thermally conductive layer may be formed as one entity, which is releasably attached to the frame by way of one or more mechanical fasteners. Optionally the surface screen is formed as part of the same entity.
The additive may comprise one or more of: carbon based particles; ceramic particles; and metallic particles.
The support layer may comprise: a central supporting portion, which supports the photovoltaic element, and optionally comprises silicone and optionally the additive for improving the thermal conductivity of the support layer; and a polymer surround portion surrounding the central supporting portion, which comprises a polymer and optionally the additive for improving the thermal conductivity of the support layer.
The photovoltaic element may be a monofacial solar cell.
The light transmitting surface screen may comprise a transparent polymer such as epoxy.
The electrical power generating element may be encapsulated by the surface screen. The photovoltaic element may be a monofacial photovoltaic element, and the encapsulation may be on the upper side of the photovoltaic element only. The monofacial photovoltaic element may rest on a heat conducting support surface. The photovoltaic element may be a bifacial photovoltaic element, and the encapsulation may be on both the upper and lower sides of the photovoltaic element. The portion of the surface screen below the photovoltaic element may rest on a support surface, which may be heat conducting.
The frame may comprise a frame recess, in which the power generating element and surface screen are located, and a border surrounding the recess, wherein the upper surface of the border is substantially coplanar with the upper surface of the surface screen.
The frame may be polygonal in plan, for example a regular hexagon, a rectangle or a square. The frame may be irregular in plan, for example having a perimeter comprising a plurality of straight sides and a plurality of curved sides.
The frame may be of concrete, other cementitious material, plastic, recycled plastic, polyurethane, fiberglass or a mixture thereof. The frame may be reinforced with steel or glass reinforced plastic or other reinforcing material. Relatively light-weight polyurethane or fiberglass may optionally be used to form the frame, and can be especially advantageous in certain circumstances, for example, when the paving module is installed on a marine vessel deck.
The surface screen may be circular or polygonal in plan, for example a regular hexagon, a rectangle or a square. The surface screen may be irregular in plan, for example having a perimeter comprising a plurality of straight sides and a plurality of curved sides.
The at least one photovoltaic element may comprise at least one substantially planar solar cell oriented in a tilted plane which is tilted relative to the planar upper surface of the light transmitting surface screen.
The tilted plane may be tilted at an angle of between 15 and 45 degrees relative to the planar upper surface of the light transmitting surface screen.
The surface screen and the power generating element may be part of a tracking disc which is circular in plan and arranged for rotation relative to the frame about a rotational axis perpendicular to the planar upper surface of the light transmitting surface screen.
Optionally, the heat sink is adapted to be embedded in a substrate below the frame; and the ground plate is adapted to be embedded in substrate below the frame.
The solar paving module may further comprise a driver for driving rotation of the tracking disc, the driver comprising a vertical drive shaft rotationally driven by an external actuator. The external actuator may comprise one or more drive rods or drive cables offset from the rotational axis of the tracking disc and connected by a crank to the vertical driveshaft. Each group of drive rods or drive cables may be movable by a central motor or central geared motor unit
According to a second aspect of the present invention there is provided a solar paving module comprising:
A paving module is a module which can be located on the ground as a load bearing paver. It is capable of bearing the loads associated with the environment in which it is used, for example pedestrian or vehicle loading, without damage.
Instead of the photovoltaic element comprising at least one substantially planar solar cell oriented in a tilted plane which is tilted relative to the planar upper surface of the light transmitting surface screen, the photovoltaic element itself may be oriented such that it is tilted relative to the planar upper surface of the light transmitting surface screen.
The tilted plane may be tilted at angle of between 5 and 50 degrees, optionally between 15 and 45 degrees, relative to the planar upper surface of the light transmitting surface screen. The actual angle of tilt may be selected depending upon where the module is to be installed, so that the angle of tilt is optimised depending on the local position of the sun and the variation in position of the sun between summer and winter. If the module is to be installed in at a location having a latitude of between 20 and 30 degrees, the angle of tilt may be between 15 and 25 degrees, or about 20 degrees. In locations nearer the equator the tilt angle is smaller than at locations further from the equator. Larger and smaller tilts are possible, outside the above range, to suit local conditions.
The electrical power generating element may be encapsulated by the surface screen. The electrical power generating element may be a monofacial photovoltaic element, and the encapsulation may be on the upper side of the photovoltaic element only. The monofacial photovoltaic element may rest on a heat conducting support surface. The photovoltaic element may be a bifacial photovoltaic element, and the encapsulation may be on both the upper and lower sides of the photovoltaic element. The portion of the surface screen below the photovoltaic element may rest on a support surface, which may be heat conducting. The electrical power generating element may comprise one or more elements of monocrystalline, polycrystalline, amorphous, single-junction, multi-junction, silicon-based, cadmium telluride based, quantum dots-based, and concentrated photovoltaic elements.
The solar paving module may comprise a plurality of photovoltaic elements arranged parallel to each other, each photovoltaic element comprising at least one substantially planar solar cell oriented in a tilted plane which is tilted relative to the planar upper surface of the light transmitting surface screen, or each photovoltaic element being oriented such that it is tilted relative to the planar upper surface of the light transmitting surface screen.
The solar paving module may comprise a corrugated support sheet comprising a plurality of parallel support surfaces, each support surface having at least one photovoltaic element of the power generating element supported thereon. The support sheet may be of a thermally conductive material, optionally of a metal such as steel, aluminium or an alloy thereof.
The solar paving module may comprise a heat sink in thermal connectivity with the power generating element. The heat sink may comprise a heat sink plate and a heat sink anchor connected to the heat sink plate.
The heat sink anchor may comprise a plurality of heat dissipating fins, which may be arranged to extend radially outwardly from the heat sink anchor.
The corrugated support sheet may comprise the heat sink plate. Alternatively the heat sink plate may comprise a substantially planar base plate and a plurality of photovoltaic element supports connected to the substantially planar base plate, wherein the power generating element is supported on the photovoltaic element supports.
Alternatively the heat sink anchor may comprise one or more ground plates connected to the heat sink plate. The heat sink plate may be substantially parallel to the planar upper surface of the light transmitting surface screen and the one or more ground plates may extend substantially perpendicular to the heat sink plate. The heat sink plate and the one or more ground plates may be a single folded plate, which may be metallic or non-metallic, for example steel, aluminium or an alloy thereof.
Alternatively the heat sink plate and/or the one or more ground plates may comprise one or more metallic mesh panels. The heat sink plate which is substantially parallel to the planar upper surface may comprise a metallic mesh panel and the one or more ground plates which extend substantially perpendicular to the heat sink plate may each comprise an upper metallic mesh panel portion and a lower plate portion.
The frame may comprise a recess, in which the power generating element and surface screen are located, and a border surrounding the recess, wherein the upper surface of the border is substantially coplanar with the upper surface of the surface screen.
The frame may be polygonal in plan, for example a regular hexagon, a rectangle or a square. The frame may be irregular in plan, for example having a perimeter comprising a plurality of straight sides and a plurality of curved sides.
The frame may be of concrete, other cementitious material, plastic, recycled plastic or a mixture thereof. The frame may be reinforced with steel or glass reinforced plastic or other reinforcing material.
The surface screen may be circular or polygonal in plan, for example a regular hexagon, a rectangle or a square. The surface screen may be irregular in plan, for example having a perimeter comprising a plurality of straight sides and a plurality of curved sides.
The electrical connector may be adapted to form an electrical connection with an electrical connector of a second like solar paving module when the solar paving module is placed next to the second like solar paving module.
The surface screen and the power generating element may be arranged for rotation together relative to the frame. The surface screen and the power generating element may together form a tracking disc which is circular in plan and arranged for rotation about a rotational axis perpendicular to the planar upper surface of the light transmitting surface screen. The tracking disc may also include the corrugated support sheet and/or the heat sink plate.
The solar paving module may comprise a driver for driving rotation of the tracking disc. The driver may comprise an electrical motor in the solar paving module.
Alternatively the driver may comprise a vertical drive shaft rotationally driven by an external actuator.
In one embodiment the vertical drive shaft may comprise a shaft of the heat sink anchor. The shaft of the heat sink anchor may extend along the rotational axis of the tracking disc. The shaft of the heat sink anchor may be rotationally fixed to the tracking disc. The shaft of the heat sink anchor may be arranged for rotation in a bearing unit. The bearing unit may be connected to a plurality of heat dissipating fins of the heat sink anchor.
The external actuator may comprise a drive rod offset from the rotational axis of the tracking disc and connected by a crank to the shaft of the heat sink anchor. The drive rod may connect a plurality of cranks of a plurality of solar paving modules. The drive rod may be driven by an electric motor.
Alternatively the external actuator may comprise a pair of drive cables, each offset on opposite sides of the rotational axis of the tracking disc and each connected by a crank to the shaft of the heat sink anchor. The pair of drive cables may connect a plurality of cranks of a plurality of solar paving modules. The pair of drive cables may be driven by an electric motor in opposite directions. The motor may be geared or gearless.
According to a third aspect of the present invention there is provided a paving construction comprising a plurality of solar paving modules according to the first or second aspect, the electrical connector of each of the plurality of solar paving modules being connected to the electrical connector of another of the plurality of solar paving modules.
Each of the plurality of solar paving modules may comprise a plurality of electrical connectors, each electrical connector being connected to the electrical connector of another of the plurality of solar paving modules and/or an electrical storage means and/or an electrical or electronic interface.
According to a fourth aspect of the present invention there is provided a paving construction comprising a plurality of solar paving modules according to the second aspect of the invention arranged in a line, wherein the surface screen and the power generating element of each solar paving module together form a tracking disc which is circular in plan and arranged for rotation about a rotational axis perpendicular to the planar upper surface of the light transmitting surface screen, wherein each solar paving module comprises a vertical drive shaft rotationally driven by an external actuator for driving rotation of the tracking disc.
The electrical connector of each of the plurality of solar paving modules may be connected to the electrical connector of another of the plurality of solar paving modules.
The external actuator may comprise a drive rod offset from the rotational axes of each of the tracking discs and connected by a respective crank to each vertical drive shaft. The drive rod may be driven by an electric motor, which may be geared or gearless.
Alternatively the external actuator may comprise a pair of drive cables, each offset on opposite sides of the rotational axes of each of the tracking discs and connected by a respective crank to each vertical drive shaft. The pair of drive cables rod may be driven by an electric motor in opposite directions. The motor may be geared or gearless.
According to a fifth aspect of the present invention, there is provided a railway comprising:
The at least one fastening member may be arranged to attach the one or more ground plates to at least one of the rails.
The invention will now be described, by way of example only, with reference to the drawings in which:
and
Referring to
Each photovoltaic element 16 is supported on a photovoltaic element support 70, which is fixed to a substantially planer base plate 68. The plate 68 and support 70 are of a heat conducting material, optionally a metal such as steel, aluminium or an alloy thereof, and conduct heat away from the photovoltaic elements 16.
There is a gap between the tracking disc 90 and the border 34 of the frame 12 which surrounds the recess 32. The upper surface 36 of the border 34 is co-planer with the upper surface 20 of the light transmitting surface screen 18 of the tracking disc 90.
The base plate 68 is fixed to a heat sink anchor 64 which in use extends into the ground on which the solar paving module 10 is installed. In the embodiment of
When installed, the solar paving module 10 is supported in the ground both by the lower end of the heat sink 60, and by the underside of the frame 12. If required, a spacing sleeve can be provided around the vertical drive shaft 100, so that the vertical dive shaft is not in direct contact with the surrounding ground.
In an alternative embodiment, the bearing unit 104 is omitted and the fins 66 are free to rotate with the drive shaft 100 in a cavity under the paving module.
The rotation of the tracking disc 90 can be controlled by an electric motor within the solar paving module (not shown) or by an external actuator, which is described below. The rotation of the tracking disc 90 provides variable orientation of the tilted rows of photovoltaic elements 16 towards the sun throughout the day. In practice this rotation can be step-wise and is extremely slow. For example, the tracking disc 90 may rotate through about 90° to 100° over a period of 6 hours, which may be the period of time during which the sun is sufficiently high in the sky for useful power generation. This requires a rate of rotation of the order of only 1 degree every 4 minutes or so. In practice therefore a step change of 1° can be provided every 3 to 4 minutes.
During the night, the tracking disc 90 can be rotated step-wise (or at any predefined rotational speed) in the reverse direction to return to the initial position, ready for next day.
A simple, rigid and long-life mechanism utilizing high torque transmission ratios can be powered by one or more central low-power controlled motors, as described below with reference to
A solar paving module 10 according to a second embodiment is described with reference to
A number of electrical connectors 22 are provided around the edge of the solar paving module 10, to permit adjacent solar paving modules 10 to be electrically connected together.
Alternatively, the heat sink plate 62 has an aperture 72 in the middle through which connecting wires (not shown) are used to electrically connect the photovoltaic cells 16 to the terminals of the electrical connectors 22. The connecting wires can be routed down the hollow shaft 64.
The heat sink 60 comprises a heat sink plate 62, which in this case is a flat horizontal plate 62 enclosed inside the surface screen 18. The plate 62 does not necessarily need to be of the same shape as the screen 18, and can be of round, square, polygonal or irregular shape. The plate 62 rests on the heat sink anchor 64, which in this embodiment is a vertical hollow shaft. The heat dissipating fins 66 are optionally connected to the heat sink anchor 64 below ground level. As in the embodiment of
The heat dissipating fins 66 can be of any suitable shape to provide a large surface area in direct contact with the ground for better heat dissipation. Instead of the generally rectangular shape illustrated in
In another alternative the heat sink plate 62 could extend beyond the surface screen 18 into the border 34 of the frame 12, surrounding the recess 32, so that the heat sink plate 60 is at least partially embedded in the frame. It can be embedded during the moulding of the frame 12. For example, if the screen 18 is round, a square plate 62 of side length similar to or close to the screen diameter will increase the mechanical strength of the combined structure of the screen 18 and frame 12.
The photovoltaic elements 16 are arranged in parallel rows and each element rests separately on a metal holder, in this case a corrugated support sheet 50 integral with the heat sink plate 62. As in the embodiment of
In case of bifacial photovoltaic elements 16, the corrugated support sheet 50 or other holders must be made of a transparent material; for instance, a polymer-based holder, or a hollow metallic frame that exposes the back side of the photovoltaic elements 16 to reflected or diffused sunlight. The photovoltaic elements 16 are tilted at an angle α relative to the planar upper surface of the surface screen 20. The exact tilt angle α is decided in the manufacturing phase based on the installation location of the system and the corresponding optimal solar tilt angle. Once set to the correct angle during manufacturing, the photovoltaic elements cannot change their tilt angle later being surrounded by the solid encapsulation material of the surface screen 18.
In an alternative method of mounting the photovoltaic elements 16, which is applicable to the embodiment of
In the case of monofacial photovoltaic elements, the elements 16 rest directly on the corrugated metal support sheet 50 or the separate rectangular metal sheets, which are set at the required tilt angle.
In the embodiment of
The motor 126 is typically an electric geared motor, i.e. a motor-gearbox assembly with a high gear ratio, with a horizontal pulley connected to its output shaft. In the embodiment of
The drive rods 106 and cranks 108 form a four-bar linkage mechanism. The motor 110 is configured to transmit the rotating motion to the tracking discs 90 simultaneously to achieve the tracking rotation. The drive rods 106 and cranks 108 can serve as additional heat dissipation means.
If a geared motor is used, the gearbox transmission ratio is selected to be high enough such that the produced torque is sufficient to rotate the tracking disc 90 in each connected paving module 10 for the required small angular step, even if there is a vertical loading on the tracking disc 90 due to pedestrians or other traffic, and to overcome any friction between the moving parts and the surrounding soil.
Instead of the fins 66 being static and the shaft 102 of the heat sink anchor being supported in a bearing unit 104, the fins 66 may be rigidly connected to the shaft 102, and may rotate with the shaft. In this case the fins 66 are of a shape that can rotate smoothly with minimum friction against soil, for example the fins may be cylindrical shaped fins. Alternatively, the fins 66 can be allowed to rotate inside a cavity of a slightly bigger diameter than the fin diameter. The cavity may be formed by a spacing sleeve.
If bifacial photovoltaic elements 16 are used, the side walls and/or bottom section of the surface screen 18 below the level of the photovoltaic elements 16 can be provided with embedded curved or flat reflector elements (not shown) to direct as much ground-reflected and diffuse light as possible to the bottom surface of the bifacial photovoltaic elements 16.
b show a further embodiment of a solar paving module 10 according to the invention. The module 10 of
In the embodiment of
If bifacial photovoltaic elements 16 are used, they are embedded in the surface screen 18 such that there is a transparent layer below the photovoltaic elements 16 as well as on top. The walls and/or bottom section of the surface screen 18 below the level of the photovoltaic elements 16 can optionally be provided with embedded curved or flat reflector element(s) to direct as much incident light as possible to the bottom surface of the bifacial photovoltaic elements 16. Alternatively the bifacial photovoltaic elements 16 can be utilized in a 2-layer surface screen structure, which includes, from top to bottom, the transparent surface screen 18, the bifacial photovoltaic elements 16, another transparent polymer-based layer, and the frame 12.
Referring to
Referring now to
As shown in
With reference to
The monofacial photovoltaic elements 216 are covered by a surface screen 218, which is housed within a frame 234 (as shown in
The support layer 217 optionally comprises a central supporting portion, which supports the photovoltaic elements, and a polymer surround portion which is formed from a polymer and surrounds the central supporting portion. The central supporting portion optionally comprises silicone. Each of the central supporting portion and polymer surround portion may comprise additives to improve the thermal conductivity of each portion. Suitable additives may be one or more of the following: carbon-based fillers such as graphite particles or graphite nanoplatelets (GNPs); and metallic or ceramic fillers such as aluminium oxide, aluminium nitride and silver. Optionally, the central supporting portion comprises silicone with 50% to 60% of its content being composed of a hybrid filler comprising large-sized aluminium oxide and small-sized aluminium nitride particles.
As shown in
The frame 234 may be formed of any suitable material, such as concrete, other cementitious material, plastic, glass, polyurethane, fiberglass or reinforced plastic. As shown in
The projections 252 may be formed of metal, and may be integrally formed with the foundation plate 250.
Alternatively, the projections 252 and foundation plate 250 may be formed as separate elements. In this arrangement the foundation plate 250 may comprise foundation plate slots which the projections 252 extend through. In this arrangement, the projections may be part of C-members (like item 60 explained in connection with
The foundation plate and/or horizontal portion of the C-member provide improved strength to the module 200 and/or frame 234.
As shown in
In the example depicted in
Furthermore, the surface screen of the ninth embodiment may be arranged to rotate like the third, fourth and eight embodiments of the invention. When the surface screen 218 is arranged to rotate in the ninth embodiment, the surface screen must be circular to allow rotation. Furthermore, the fixings 221 must not be present to allow the screen to rotate freely within the frame 234. The frame 234 is fixed with respect to the heat sink 260, and the socket 258 is rotatably mounted on the heat sink by way of a bearing, meaning the socket is allowed to rotate. The electrical terminals snap-fit into the socket 258. Heat can be conducted from the heat conducting layer to the heat sink via the hollow shaft 240. The shaft 240 extends into the projection via an additional recess for receiving the shaft provided in the projection 256, and is connected to the rotatably mounted socket, thereby meaning the shaft can rotate also. Optionally, a shaft extension may be provided upon a lower end of the hollow shaft 240 which extends below the projection 256. Alternatively, there may be no shaft extension and the shaft itself may extend below the projection 256.
The shaft, the shaft extension and/or socket may be connected to a crank or drive mechanism. The shaft 240 may further dissipate heat by the provision of fins or concentric rings. In a variation of this arrangement, the frame 234 may be completely hollow and locked mechanically to the heat sink via two interlocking members, where one of the two interlocking members is provided on an underside of the frame 234 and the other is provided on an upper surface of the heat sink 260.
As an alternative to the rotational mechanism described above, the rotational mechanism of the third, fourth and eighth embodiments of the invention may be incorporated in the module of
The hollow shaft 240 may comprise external and internal shafts. The internal shaft may be releasably connected to the external shaft such that the internal or external shaft may be removed to access a protection/bypass diode electrically connected to the photovoltaic elements 216. The internal shaft may be releasably connected to the external shaft by way of a threaded arrangement.
Alternatively, the external shaft may be releasably connected to the internal shaft such that the internal or external shaft may be removed to access a protection/bypass diode electrically connected to the photovoltaic elements 516.
The external shaft may be releasably connected to the internal shaft by way of a threaded arrangement.
The heat sink 260 of
With reference to
The piece 535 comprises the transparent surface screen 536, which encloses the photovoltaic elements 516, and optionally is formed of transparent polymer, such as epoxy, which is cast over the photovoltaic elements 516. Each photovoltaic element is provided upon a support 517, which optionally provides electrical insulation and shock absorption under excessive mechanical overloads to avoid fracture of the photovoltaic element. The support optionally comprises silicone. Optionally, additives which act to improve the thermal conductivity of the support 517 are provided in combination with the silicone in each support 517. The supports 517 are themselves provided upon a corrugated sheet 520 in this example. The corrugated sheet 520 is typically formed of metal and in this example comprises angled portions upon which the supports 517 rest.
The corrugated sheet 520 is itself provided upon a polymer layer 522, which typically comprises a polymer such as epoxy, and optionally additives to improve the thermal conductivity of the polymer layer. The polymer layer 522 is optionally provided upon a thermally conductive layer 523, which typically comprises a metal. Optionally, the thermally conductive layer 553 is formed of a metal plate. Optionally, the thermally conductive layer 523 may be bonded to the corrugated sheet 520 along its periphery to enhance thermal conduction
A hollow shaft 540 depends from the thermally conductive layer 553, and has located therein electrical terminals 538. Electrical connections connected to the photovoltaic elements extend from the photovoltaic elements through the hollow shaft 540 to the electrical terminals 538. When attached to the heat plate 260, the shaft may extend beyond the heat plate 260. Optionally, a shaft extension may be provided.
The hollow shaft 540 may comprise external and internal shafts. The internal shaft may be releasably connected to the external shaft such that the internal or external shaft may be removed to access a protection/bypass diode electrically connected to the photovoltaic elements 516. The internal shaft may be releasably connected to the external shaft by way of a threaded arrangement.
Alternatively, the external shaft may be releasably connected to the internal shaft such that the internal or external shaft may be removed to access a protection/bypass diode electrically connected to the photovoltaic elements 516. The external shaft may be releasably connected to the internal shaft by way of a threaded arrangement.
Suitable additives to improve the thermal conductivity of the supports 517 and polymer layer 522 include one or more of the following: carbon-based fillers such as graphite particles or graphite nanoplatelets (GNPs); and metallic or ceramic fillers such as aluminium oxide, aluminium nitride and silver. Optionally, each support comprises silicone with 50% to 60% of its content being composed of a hybrid filler comprising large-sized aluminium oxide and small-sized aluminium nitride particles.
With reference to
Each module 200 is held in place between the rails by a fastening member 456. As shown each fastening member 456 is secured to each paving module 200 and to a foot portion of each parallel rail 452.
The fastening member 456 used in
The base plate 460 is secured to each rail 452 via rail securing components 470 attached to respective base plate flanges 462 of the base plate 460 (as shown in
An advantage of the arrangement of
The invention can be used in the vast areas of sunny pedestrian walkways and yards found in cities, towns, and villages in many regions of the world. Traditional solar panels are not walkable, but the solar paving modules of the present invention allow these spaces to become potential sources of power. The solar paving modules of the present invention can withstand heavy weight or mechanical loads of people, bikes, and the occasional loading of lightweight slow-speed vehicles. Unlike conventional solar panels, which are normally mounted on tilted frames or supported with an underneath clearance to allow for air flow, and depend on natural air flow for cooling, the solar paving modules 10 of the present invention have a non-glass light transmitting surface screen 18 to reduce heat absorption and in-built heat sinks to carry away the heat that is generated by the photovoltaic elements 16.
The frame 12 and solar paving module 10 can be of any suitable shape. The shape is not limited to the illustrated examples. For example it can be of a circular, triangular, square, rectangular, hexagonal, polygonal, or any other regular or irregular shape.
The surface screen 18 is made of a transparent material of suitable optical characteristics. The surface screen provides sufficient mechanical strength, durability, inherent (or added) anti-slip property, inherent (or added) anti-scratch property, and inherent (or added) hydrophobic (dust and water repelling) property. The surface screen material is selected to satisfy the required light transmittance requirements. Its degree of transparency and colour can vary from partially opaque to full transparent depending on the installation location requirement. The surface screen 18 also serves as part of the passive cooling system integrated in the solar paving module. For this reason the surface screen 18 is optionally made of a clear polymer. A polymer-based resin material, for example an epoxy resin manufactured for flooring purposes, has been found to be particularly beneficial, since it traps less heat than the conventional glass material. The use of an epoxy material offers several advantages over glass. Firstly, to withstand the loads a paver needs to withstand, a significantly thick layer of glass must be used at an associated high cost. Secondly, smooth glass is slippery and cannot be used as a walking surface, hence an additional process of surface preparation has to be applied to add a texture to make it suitable for walking on, at the expense of manufacturing time and product cost. Thirdly, glass has a greenhouse effect, it traps heat beneath it which leads to increased temperatures of the photovoltaic elements and hence reduced power production and reduced life span of the photovoltaic elements. Polymer-based resin (e.g. epoxy) surface structures, on the other hand, are of lower cost and easier to manufacture. They have better thermal performance, since they do not trap heat and they dissipate it much better than glass.
The surface screen 18 itself can be of circular, square, or polygonal shape and rests on the frame such that the border 34 of the frame 12 encloses the screen from all sides except the upper face. However, where a tracking disc 90 is not required, in one variation the surface screen 18 can extend above the recess 32 in the frame 12 and cover the upper surface 36 of the border 34.
The power generating element 14, which is encapsulated in the surface screen 18, can comprise a monocrystalline, polycrystalline, amorphous, or another form of photovoltaic element 16 or a number of such elements 16 connected together in series or parallel or a combination of series-parallel connections to generate a certain amount of power by converting incident light to electricity. The photovoltaic elements 16 can be of different sizes and shapes; they can be bifacial (i.e. generating power by light incident on both upper and lower faces) or single-face.
The frame 12 can comprise one layer; or two or more interlocking or dove-tailed layers, as illustrated in
The heat sink 60, and the metal components which make up the heat sink 60, such as the heat conducting support surface 26, the heat sink plate 62 and the heat sink anchor 64, serve a number of purposes.
Firstly, the heat sink 60 acts as a heat dissipation element discharging the heat generated by the power generation process by means of geothermal cooling, thereby limiting the operating temperature of the photovoltaic element 16. In general higher temperatures may lead to less efficient power generation. In certain photovoltaic technologies a higher temperature of the photovoltaic element 16 above 45° C. means almost 0.5% less power production for each degree above 45° C. Cooling is therefore essential when installing modules 10 in very sunny places, and is generally advantageous in all locations. The passive cooling of the present invention, which is based on geothermal cooling principles, solves this problem by dissipating excess heat to the soil.
Secondly, the heat sink 60 increases the mechanical strength of the solar paving module 10, since the metal components act as reinforcing elements.
Thirdly, the heat sink 60, and in particular the heat sink anchor 64 or ground plates 80, can be used to fix or mount the paver firmly in the ground. This further enables a firm connection with the underlying soil for effective heat management. The heat sink 60 can take many shapes and designs as illustrated in the above embodiments.
The solar paving module 10 can include an electronic junction box (not shown) or can have a separate electronic junction box (not shown). This can be a weatherproof sealed box which is placed underneath each paver. Alternatively a single junction box can serve a group of pavers. The junction box can house electronics, for example a bypass diode(s) and/or blocking diode(s) as appropriate. The bypass diode can bypass a paver if it gets shaded, thus protecting the encapsulated PV cells from thermal damage by hotspots. A blocking diode is needed in each string of pavers to block current flow in reverse.
Each solar paving module 10 has at least one electrical connector 22, 23, optionally comprising terminals 23a, 23b arranged in pairs, each pair comprising a positive terminal and a negative terminal. The terminals connect each paver to one or more adjacent pavers. Optionally the connectors are weatherproof, and are connected internally to appropriately insulated wires.
A number of solar paving modules 10 are grouped together in strings of series, parallel or series-parallel connected units to build up the required system power and voltage outputs. The solar paving modules 10 together form a paving construction.
The terminals of the connector 22 of the solar paving module 10 can be connected to an electronic converter or microinverter to convert DC to AC and to connect to the grid and/or loads. In another embodiment the terminals of the connector 22 of the solar paving module 10 at the end of each string are connected to an electronic converter or microinverter to convert DC to AC and to connect to the grid and/or loads. The microinverters are all connected in parallel at their AC side to feed the grid and/or local loads. Alternatively, strings of series connected solar paving modules 10 may be connected in parallel through a combiner box housing connection points and protection devices, and the terminals of the combined system are then connected to an aggregate electronic converter converting DC to AC (string/central inverter).
In both types of electric interface system described above, electronic converters and control circuitry may be housed either outdoors in protective and/or weatherproof enclosures of high IP (Ingress Protection) number or indoors. Battery banks can be optionally connected to either type of electric interface systems through appropriate control and charging circuitry, which can be similar to traditional solar PV systems. Batteries may be housed in protective enclosures of high IP number, appropriately buried in soil, or placed indoors in a protected environment.
In one method for mounting the solar paving modules 10 on the ground, the solar paving modules 10 are laid against one another in an array over a bedding of sand and gravel, in a method similar to that used for traditional paving stones. This method allows simple replacement of a solar paving modules 10 in case of malfunction, i.e. a single solar paving module 10 can be easily lifted up and replaced. However, in contrast to traditional paving stone installation, the solar paving modules 10 of the invention may also be fixed to the bedding via the heat sink anchors 64 or ground plates 80. This provides increased strength and rigidity of the pavement, i.e. the paving construction.
In some embodiments, an interlocking means may be provided. For example in the embodiment of
When there is no structural interlocking mechanism, for example in the embodiments of
An advantage of the two component frame 12 illustrated in
In any of the embodiments, regardless of whether the frame 12 is entirely made of concrete or has a concrete layer, plastic granules can be added to the concrete mix for reinforcement. The granules can be of recycled plastic.
The presence of bypass diode(s) in every solar paving module 10 means that even in case of photovoltaic element failure or malfunction, the module can be successfully bypassed and ceases to generate power while the rest of the paving module string is fully functional. The same applies when one or more modules 10 get shaded, although the bypass is of a temporary nature in this case and ceases when the shading ceases.
The invention offers the advantage that the photovoltaic element 16 can be tilted to the optimal tilt-angle at the location of installation, unlike existing solar floor pavers in which the photovoltaic element is fixed in a horizontal position.
In the embodiment with a rotatable tracking disc 90 the surface screen 18 and the embedded photovoltaic elements 16 can be made to rotate around the vertical axis in small steps inside the paver frame 12 to provide variable orientation of the tilted rows of photovoltaic elements 16 rows to track the sun during the day. The reliable long-life rotation mechanism is placed underneath the modules 10 to manage the small step-wise orientation of surface screens. It can contribute to the overall structural strength of the paver system and also contribute to enhanced heat dissipation to ground. In practice, it may be desired to rotate the tracking disc 90 to 100 degrees over a period of 6 hours, during which there is useful sunshine. This requires minimal energy, because the speed of rotation is less than 1 degree every 3 minutes.
Bifacial photovoltaic elements 16, which can utilize light from both sides, can be used in the modules 10. In such cases, flat or curved collectors/reflectors can be embedded to the side walls and bottom section of the recess 32 in the frame 12 below the level of the bifacial photovoltaic element 16 to direct as much incident light as possible to the lower surface of the bifacial photovoltaic cells. The use of bifacial photovoltaic cells can significantly increase the electric yield, since power can be generated by light incident on both faces.
The support and thermal conducting layers described in connection with the ninth embodiment above may be incorporated in the other embodiments of the invention. For example, they may be incorporated in a solar paving module with photovoltaic elements which are tilted with respect to the upper surface of the surface screen, like in the embodiment of
The modules may have hexagonal or octagonal shaped frames and surface screens in the array of modules shown in
In the embodiments,
The heat sink of
The level of thermal conductivity enhancement in the polymer layer and silicone sheets depends on the percent filler/additive content. For instance, epoxy thermal conductivity can be boosted more than 10-fold with 50-60% content of hybrid filler composed of large-sized aluminium oxide and small-sized aluminium nitride particles. This would make the thermal conductivity of the epoxy layer significantly higher than glass.
One benefit of the claimed subject matter is enhanced efficiency in hot regions. The optional inclusion of polymers like epoxy for example provide better heat management properties, are more cost effective and have better mechanical durability than known solutions. The claimed subject matter also provides enhanced thermal conductivity through the heat sink in each paver. The heat sink optionally provides advantages in terms of mechanical strengthening of the surface screen and frame structures as well as firm mounting to the ground or base.
Advantageously, the support layer may act as a shock absorber to avoid fracture of the power generating module in case of sudden force or overload applied to the surface screen 235 or 535.
Modifications and variations are possible without departing from the scope of the invention. In particular the invention is not limited to the particular shapes and materials described above.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1915051.5 | Oct 2019 | GB | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2020/059818 | 10/19/2020 | WO |
