WO2011076456A1

WO2011076456A1 - System, assembly and method for a hybrid system for converting solar radiation into electric current and heat

Info

Publication number: WO2011076456A1
Application number: PCT/EP2010/065352
Authority: WO
Inventors: Hansjürg Leibundgut
Original assignee: 3S Swiss Solar Systems Ag
Priority date: 2009-12-22
Filing date: 2010-10-13
Publication date: 2011-06-30
Also published as: EP2517266A1; CH702438A1

Abstract

In a device for converting solar radiation into electric energy by means of a photovoltaic solar cell, the solar cell (11) is connected to a heat transport medium (3) in a heat-conducting manner in order to at least partially dissipate the solar radiation converted to heat in the cell.

Description

System, arrangement and method for a hybrid system for converting solar radiation into electricity and heat

The invention relates to an arrangement for the utilization of

Solar radiation with simultaneous production of electricity from photovoltaic solar cells and thermal energy according to the preamble of claim 1, and a method for

Utilization of solar radiation for generating electrical

Energy as well as thermal energy.

Solar radiation is an energy form, the majority in rel. shortwave frequency range of less than 2 microns

Wavelength on the earth's surface occurs. The energy of

Solar radiation can be partially converted into electricity or also partially into heat energy. In both processes of energy conversion, the energy of the photons becomes the

Solar radiation partially absorbed by a solid body. In the photovoltaic cell, the highest possible proportion of energy from the photons is transferred directly into an electrical energy stream

transformed .

The proportion of absorbed radiant energy can not be 100% converted into electrical energy. The remainder is partially converted into thermal energy that must be dissipated from the photovoltaic cell to maintain its performance. Since the photovoltaic effect depends on the temperature of the absorbing layer (higher temperatures reduce the electrical efficiency), the heat must be dissipated from the photovoltaic cell at a relatively low temperature. The photovoltaic layer is very thin and, for reasons of strength, must be fixed mechanically to or on a support plate which absorbs the various forces on the surface and transmits them to a supporting structure, which in turn is firmly connected to the earth. The element consisting of the

Photovoltaic layer and the force-transmitting support plate is referred to as a solar panel.

Existing or known systems for the recovery of

Heat to be dissipated from photovoltaic cells is usually oriented to heat at the highest possible temperatures and as extensively as possible over the absorbing layer

decouple. This results in complex panel constructions. Such systems are known, for example, from WO 2009/149572, DE 20 2007 010 901, DE 20 2007

000529, EP 1 914 489 and DE 20 2007 009 162.

The object of the present invention is to be able to dissipate the heat generated in conventional solar panels with a simple additional device. Not the temperature of the dissipated heat flow in the foreground but much more the amount of heat and a low design effort.

Another goal is to put pressure on the backside everywhere

build up on a large area without damaging the photovoltaic layer at the same time. Typically, the device according to the invention covers less than 100% of the panel surface, a value in consideration of the energy efficiency and the design effort or cost.

The object is achieved by an arrangement with the features of claim 1 and the other, derived therefrom and dependent claims, the descriptions and the drawings.

The inventive heat removal device consists of

at least one heat transfer element and means for guiding a heat transfer medium, which are thermally conductively connected to the element.

The at least one heat transfer element, such as a plate, is flat with the solar panel, at least

consisting of photovoltaic layer and back

Cover connected thermally conductive. The means for that

Guiding, such as a heat transfer tube may be formed at the ends of the heat dissipation device into a circular tube, so that more solar panels or on a

Heat transfer medium Zu-, resp. Return line can be connected (shown in Figure 3 and 5). With an additional processing step, a mold profile (e.g.

Extrusion profile or the like), for example, a freestanding circular tube can be created (shown in Figure 8).

The pipe section of the heat transfer tube on the

Heat transfer plate may take other than the circular shape (shown in Figure 6, section B). The Heat transfer tube should be as large as possible

Have heat transfer surface to the heat transfer plate. In one shown in Figure 7 or correspondingly appropriate

Manufacturing method, the pipe can be shaped accordingly. In an uninterrupted pipe section, the connecting pieces may also be contained from one heat transfer plate to the next. The heat transfer tube can out

be formed of different materials. Several

Heat transfer tubes can be interconnected in series or in parallel. The connection of the heat transfer tubes can with another heat transport tube from quite another

Material exist. The connecting tube may be made of a poorly conductive material, e.g. Plastic or similar materials, be designed to minimize the heat loss through the pipe to the environment.

By changing the mass flow of the heat transfer medium, the temperature of the heat dissipated can be influenced. At higher temperature of the heat, although the electrical sinks

Efficiency of the photovoltaic layer, but the Exergieanteil in the heat flow increases, resulting in a higher "coefficient of performance" of the heat pump, which extracts heat from the heat cycle and transformed to a higher temperature. The exergetic overall efficiency of the system consisting of the solar panel, the heat dissipation device, the heat transport system and a heat pump can be optimized.

The inventive device for decoupling the heat from a solar panel is designed so that they are small Expenditure of a solar panel can preferably be attached to a commercial solar panel, and that the functionality of the solar panel is reduced in any way or

is impaired. This is of particular importance with respect to forces and other undesirable processes, e.g. may arise from different thermal expansion coefficients or deformations due to wind forces or formation of condensate. So the edges of the

Heat transfer plate are designed accordingly that the damage of the solar panel is avoided.

The inventive system for removing heat from an electricity-producing solar panel comprises a

Heat removal device and a fastening system, the

ensures that the heat dissipation device can be thermally conductive and frictionally but not rigidly connected to the solar panel.

In contrast to known solar combi panels, such as e.g.

proposed in WO2009 / 149572, where heat exchangers are glued only on the back layer, there is the

Fixing system, for example, a pull / push member and an anchor member.

The tension / compression member brings a compressive force vertically to the heat dissipation device and clamps them non-positively flat on the back of the solar panel. The tension / compression member generates the compressive force and acts with a tensile force on the anchor member on the connecting surface of the back

Covering layer of solar panel. This back layer de Solar panels can be made of glass, plastic, ceramic or metal.

The anchor member establishes the attachment of the pull / push member to the back cover of the solar panel. The anchor member can be applied by gluing, welding or similar joining techniques subsequently on a commercial solar panel. The anchor member may also be an adhesive itself.

Likewise, the anchor organ already in the production of

Solar panels during the lamination process with the

various building layers of a solar panel are joined.

Excessive punctual mechanical loads on the

Solar panels can cause excessive stress in the

photovoltaic cells and, in the worst case, lead to cell breakage. This is particularly critical in the case of compressive loads, which is why it is important that a tensile force is exerted on the back side layer of the solar panel, in particular for preventing cell breakage.

Furthermore, according to the invention, it is proposed to distribute the total force over several partial loads and over as large an area as possible by applying a plurality of tension / compression members regularly distributed over the entire back

to reach. The tensile load on the connection surface of the solar panel caused by the individual pull / push element is so low that it can not lead to cell breakage. The generation of the force in the tension / compression member can be both passive material stress and / or material bias (it can be used materials such as metal, plastic, or the like), as well as active with eg bimetals, thermal

Expansion, piezo elements, or be generated by the pressure in the cooling system.

The tension / compression element with bimetal functions as

self-regulating heat softener that applies pressure to the absorbed heat from the solar panel

Heat dissipation device to the solar panel to clamp. With an increasing temperature level existing in the solar panel

Heat, the clamping force is greater and the solar panel cooled more. As soon as the temperature level decreases, so does the

Clamping force and the cooling effect is reduced.

Analogously, the self-regulating fastening system with piezo elements works, which applies the necessary force for the clamping of the electricity generated in the photovoltaic layer.

In DE 20 2007 009 162, a mounting system enclosing a plate frame is proposed, which leads to a poor contact pressure being generated in the middle of the panel, contrary to the solution proposed above. In addition, can be dispensed with by the proposed solution according to the invention with surface distributed anchor on a frame as in DE 20 2007 009 162, i. a frameless solution is made possible, which can be advantageous.

The inventive arrangement makes it possible to transfer the dissipated heat from the panel by heat conduction from the photovoltaic layer in the heat dissipation device, in which the Transfer heat to a heat transfer medium and from it

can be removed.

The arrangement according to the invention makes it possible to supply heat to the panel from a heat source, e.g. Defrosting snow and ice or slipping off the panel.

The arrangement according to the invention makes it possible to carry out solar panels on the backside thermally insulated (FIG. 4), since the heat to be dissipated is decoupled by means of the heat dissipation device.

The arrangement according to the invention makes it possible to provide solar panels at the front with a skin transparent to solar radiation, e.g. from double glazing, to limit the cooling to the front, since the photovoltaic layer through the heat dissipation device can deliver heat to the heat cycle.

The inventive arrangement makes it possible, the solar panels front with concentrated solar radiation higher

Radiation power to be irradiated, as by the rear

Heat dissipation device harmful to the solar panel

Temperature increase can be limited.

The inventive arrangement makes it possible to regulate the temperature of the heat dissipated and thereby optimize the overall exergetic efficiency of a system that at least one solar panel, an inventive heat removal device, a heat transport circuit and a memory, a consumer or a heat pump.

In the inventive arrangement can with the help of

Thermal paste or similar thermally conductive aids the heat transfer of the heat transfer plate to the back layer of the solar panel can be improved. In addition, the

Friction by means of a paste between the solar panel and

Heat transfer plate can be reduced, so as to simplify, for example, the displacement of the plate and to avoid long-term damage.

According to a further embodiment of the arrangement, it is proposed that the heat transport medium is viscous or is a liquid.

Again according to another embodiment variant

proposed that the heat transfer element made of aluminum or an aluminum alloy.

As a further embodiment, it is proposed that the photovoltaic solar cell is covered on the front side with a transparent layer in order to limit the cooling on the front side.

According to a further embodiment, the solar cell or the heat transfer plate is on the back with heat-insulating Material equipped to reduce the thermal efficiency of

To increase arrangement or the system at higher operating temperatures.

Again according to another embodiment variant

proposed that several heat transport devices are lined up so close to each other and that the flow of the

Heat transport medium is so high that the solar cell can be irradiated with concentrated solar radiation.

Finally, in addition to the in the claims

proposed method further proposed that by means of the liquid heat transport medium inversely the solar panel heat can be supplied to possibly remove icing or snow on the solar panel.

The invention will be explained in more detail below, for example, with reference to the drawings. It shows purely schematically:

Fig. 1

Section through the construction of the heat dissipation device assembled with the solar panel including pull / push element and anchor element,

Fig. 2 The arrangement of several heat transfer plates with the heat transfer tube connected on a single solar panel,

Fig. 3

The assembly of several solar panels, equipped with one or more heat dissipation devices to a larger system,

Fig. 4

The heat insulated solar panel, equipped with one or more heat dissipation devices,

Fig. 5

The top view of two heat dissipation devices with broadened cross-section on the heat transfer plate,

Fig. 6

Section A according to FIG. 5 with the circular cross section at the end pieces of the heat dissipation device.

Section B according to Figure 5 with a deformed, one-sided area cross-section on the heat transfer plate.

Fig. 7

Two variants of the production of large-scale

Heat contacting the heat transfer tube with the

Heat transfer plate. Fig. 8

Representation of the post-processing step of the embodiment of a freestanding pipe from a mold profile.

Fig. 9

Side view of a connection possibility of the one

Molded tube with a connecting tube which is first mechanically expanded radially with internal pressure and can thus be connected to the freestanding tube.

The physical principle of action begins when solar

Radiation hits the photovoltaic layer 11. Part of the radiant energy is converted into electrical power and passed via the current terminal 13 to the electrical conductor 17, from where the solar power is dissipated.

The radiant energy absorbed by the surface of the layer 11 but not converted into electric current is converted into heat in the layer 11. A part of this heat is given to the overhead environment by means of radiation and convection, a part is in the back cover. 9

introduced as much of the heat of the

Lead panel in the heat dissipation device 1. For this purpose, the heat removal device 1 is pressed against the rear cover 9 in order to produce a heat-conducting contact. In the heat removal device 1, the heat is transferred to a heat transfer medium transferred, which flows in the heat transport tube 3 and removes the heat from the heat dissipation device.

The heat dissipation device 1 is pressed by means of the fastening system 5 to the back layer or cover 9. The

Fixing system 5 consists of one with the back

Layer firmly connected anchor member 7 and a possibly releasably connected pull / push member 8, which exerts a variable force. By this arrangement, the heat-conducting contact between the support plate or solar panel and heat dissipation device is ensured while allowing the possibility of at least partially horizontal displacement of the heat dissipation device to the solar panel.

The fastening system can be designed so that the

Anchoring member through recesses (10) in the heat dissipation device is performed by this or is arranged sideways next to it. In Fig. 2, both variants are shown: attachment with recesses in the heat removal device (upper

Heat transfer plate) or lateral attachment (middle and lower heat transfer plate). The recesses are

preferably dimensioned such that the

Heat transfer plate can thermally expand.

As a result of the fastening system proposed according to the invention, the anchor member 7 exerts a tensile force on the rear-side layer 9, which is advantageous because it prevents the formation of cell breakage. In addition, Fig. 2 shows the good area distribution of fasteners, which also centered in the Heat dissipation device or the heat transfer plate sufficient contact pressure is achieved.

So that the heat transfer plate does not migrate in one direction over time, for example due to thermal expansion, it can be fixed at a point or along a line. For this purpose, of course, the anchor members can be used by the recesses and the therein

arranged anchor members are dimensioned accordingly.

The backsheet or cover 9 can be made of an EVA composite layer, of glass, of a metal or of a

Multi-layer laminate consisting of the materials mentioned.

The heat transfer plate can be made of plastic, aluminum or an aluminum alloy and can be prepared for example by means of extrusion extruding, this

can be done simultaneously with the pipes arranged thereon, which are responsible for guiding the heat transfer medium.

The anchor members 7 may be attached to or in the backside layer by gluing or laminating or by using screws and other mechanical means

Fixing organs.

The tension / compression member or the mounting bracket 8 can be plugged, welded, latched, etc. on the anchor member 7. As in Figure 3, a plurality of heat dissipation devices connected to each other in series and in parallel and a Zu-, resp. Return are connected. The manner of interconnecting the individual heat removal devices can be configured differently:

Solution 1: Connect different channel profiles integrated into the heat transfer plate Using connecting tubes (27).

This is exemplified in FIGS. 8 and 9. To connect several of these heat removal devices, a circular tube is released in a further step at the ends of the mold profile (according to Figure 8). As shown in FIG. 9, this separated tube piece (28) can be provided with a connecting tube (27) which can be mechanically expanded in diameter.

get connected. For this purpose, the connecting pipe is made

expandable material mechanically expanded (29) and brought with the inner surface on the outer surface of the exempted tube and connected.

Solution 2: Heat transfer tube passing through several heat extraction plates, as shown in FIG. The

Heat transfer tube may be made circular at the ends of the heat transfer plate (Figs. 5 and 6, section A) and take on the heat transfer plate other than a circular shape (Figs. 5 and 6, section B). Two options are

Variant A, Figure 7: A corresponding shape profile 21, in which a folded heat transfer tube 22 is introduced and formed with the application of internal pressure so that it surface-fit with the mold profile 21 rests and

offers the greatest possible thermal contact.

Variant B, Figure 7: A semicircular trained

Fixing device 25 clamps a correspondingly shaped heat transfer tube 24 as large as possible on the

Heat transfer plate 23.

For the connection of several heat transfer plates can

For example, a PEX (polyethylene pipe specially crosslinked) can be used. Preferably, it is connected to a positive connection on the means for guiding a heat transfer medium. Preferably, the connecting tube is deformed or expanded, as described above under solution 1. Finally it is

possible to additionally secure the connection of the pipes by means of a ring.

According to another possible embodiment, it is possible that the heat transfer plates are formed such that they overlap and touch each other. However, an expansion, for example, thermally induced, the two plates should not be prevented. Because of this

Overlapping ensures the heat dissipation between two plates.

Finally, in Figure 4 is shown schematically and in longitudinal section the back of a solar panel, wherein the

Heat removal device is additionally covered by a thermal insulation 31.

Of course, the arrangements according to the invention shown in FIGS. 1-9 are only examples of the explanation of the present invention. Of course, the heat transfer plates may be formed differently, for example, a single plate may be provided, which is the back layer

Covered largely over the entire surface, it can be provided a variety of heat transfer plates, these can be as proposed aluminum or an aluminum alloy

exist or else from another, good thermally conductive material. The heat transfer can be additionally increased by the use of, for example, a so-called thermal grease, as used in particular in computer technology.

Again, it is possible to form the heat transfer plate slightly curved inwards with a central bias, so that by attaching the plate at the edge of an increased

Contact pressure in the middle of the plate is generated. It is also possible to overlap heat transfer plates, i. two adjacent plates abut each other

overlapping each other in the edge area.

The attachment members may be designed differently, it is essential that the anchor member used, which rests on the back layer of the solar panel, exerts a tensile force on this back layer.

Claims

claims

1. Arrangement for utilizing solar radiation with simultaneous production of electrical power from photovoltaic

Solar cells and thermal energy, characterized in that a means for generating electric current, at least consisting of photovoltaic layer (11) and a back cover (9), thermally conductive with a

Heat removal device (1) is connected, consisting of at least one heat transfer element and means (3) for guiding a heat transfer medium, wherein the heat transfer element with at least one pull / pressure fastening means (5) on the back cover (9) bears thermally conductive.

2. Arrangement according to claim 1, characterized in that the fastening device has an anchor member (7), which exerts on the back cover (9) has a tensile force.

3. Arrangement according to one of claims 1 or 2, characterized

characterized in that a plurality of anchor members (7) and tension / compression members (8) are provided, the surface in or on the

Cover and / or the heat transfer element distributed

are arranged to ensure the fullest possible contact pressure.

4. Arrangement according to one of claims 1 to 3, characterized in that the heat transfer element is a

Heat transfer plate is.

5. Arrangement according to one of claims 1 to 4, characterized

characterized in that the heat transport means a

Molded profile, in which a flexible channel is introduced.

6. Arrangement according to one of claims 2-5, characterized

in that the firm connection between anchor member and solar panel is an adhesive bond, that the anchor members are laminated in the back layer, or that between

Anchor and back cover is a welded joint, for example, produced by means of ultrasound,

High frequency, heat or laser.

7. Arrangement according to one of claims 1 - 6, characterized

characterized in that the force for the contact pressure of

Heat transport device to the solar panel via a connection such that the heat transport device on the

Solar panel is at least partially displaced without the heat-conducting contact is interrupted or reduced.

8. Arrangement according to one of claims 2-7, characterized

in that the heat monitoring element or the at least one heat transfer plate of

Heat removal device has recesses through which penetrate the attachment device or the anchor or the organs and that the recesses have a significantly larger diameter than the diameter of the anchor member.

9. Arrangement according to one of claims 1 to 8, characterized

characterized in that one or more push / pull rods are arranged laterally of the heat transport device and that the force on a bar construction of the rods on the

Heat transport device is transmitted.

10. Arrangement according to one of claims 1 to 9, characterized

in that the tension / compression fastening device has tension / pressure elements made of bimetal or piezo elements,

functioning as a self-regulating heat softener, such that with the absorbed heat from the solar panel or the electricity generated in the photovoltaic layer, force is generated in the Zug- / Duckorgan to dissipate the existing heat in the solar panel reinforced.

11. Arrangement according to one of claims 1 to 10, characterized

characterized in that the heat transport device is an im

Substantially semicircular shaped heat transfer tube

which is in a second tubular

Fastening device is guided, which in accordance with

Is formed substantially semicircular, and which as large as possible clamped on the heat transfer element.

12. Arrangement according to one of claims 1 to 11, characterized

characterized in that the means for the leadership of the

Heat transfer medium is a heat transfer tube, which is exempted in terminal or in the heat transfer element such as the heat transfer plate such that the connection of a connecting tube (27) with another heat transfer tube in or on another heat transfer plate is made possible, preferably the connecting tube extended depending terminally (29) is designed to with the exempted

Lot to be connected (28) each of the heat transfer tube.

13. A method for using solar radiation for generating electrical energy and for operating a memory, a consumer or a heat pump, characterized in that by means of an arrangement according to one of claims 1 to 12, in solar cells for conversion into electrical energy by the solar radiation generated heat, heat-conducting in one

Heat transport medium is discharged in which the heat dissipated is supplied to a memory, a consumer or a heat pump.

14. The method according to claim 13, characterized in that by the change in the mass flow of the heat transport medium the dissipated heat can be influenced by the

To optimize the overall efficiency of the arrangement or the system with respect to generated electrical energy and dissipated heat.