DE4339547A1 - Photovoltaic electricity generation by solar cells - Google Patents

Abstract

The electricity generation uses photovoltaic solar modules whose cells are cooled by air flow, wind, or pref. liq. or gaseous coolants, or by movement for the temp. control. The waste heat from cooling is pref. used for heating via heat pumps or similar cold-hot machines. If the solar cells are exposed to snow or front they are quickly heated, pref. by their own energy generation. The photovoltaic cells are mounted in physical contact on or within a plate-shaped base which is temp. controlled, i.e. gas or liq. cooled.

Description

The invention relates to a method and Vorrich for the photovoltaic production of Electricity using solar cells or for operation photovoltaic solar modules.

The electrical power of photovoltaic sun Lar cells is strongly of the operating or own temperature rature of the solar cell modules dependent; so it sinks Voltage of a monocrystalline Si solar module from for example 19V at 0 ° C to 15V at 50 ° C and its us degree of efficiency in this temperature range of around 15% up to 11%. In addition, strong temperature Differences, e.g. B. straight from day to night sunny climates due to temperature change demands, the material properties of the Solarmo dule and are probably also a reason for the life limiting degradation of solar cells after a long time Use, as well as for destructive, mechanical dila station defects, d. H. Cracking etc. and stripping sung. After all, the efficiency is also a sun lar cell in the same sense of the intensity of the on radiation itself dependent, so that the module temperature and thus the efficiency also according to the degree of on radiation should be optimized.

Object of the method and the associated devices is based on these drawbacks to avoid economically optimal way.

Accordingly, the invention is a method and a device for carrying it out, with which the photovoltaic solar cell elements using coolant means such. B. air or wind, or preferably rivers coolants or by moving temperature control liert, preferably cooled. The operating temperature rature of solar cell modules is to be used in this way set or regulate and maintain that an optima Efficiency and maximum life, d. H. optimal operating conditions can be achieved. In addition ge not only hears the cooling of solar modules and the economic use of the heat gained, but u. Sometimes an occasional warming up too low outside temperatures or in case of snow and ver ice, which also includes an additional degradation can occur.

To increase the overall efficiency of Solaran were in the process of the invention, the Cooling dissipated heat if necessary by means of heat pumps z. B. used for heating purposes.

With the method according to the invention, the Influence of wind speeds or environmental factors conditions for the optimal operation of solar modules, d. H. the influence of external air cooling or never  impact influences (also e.g. humidity) opti be lubricated.

The method according to the invention works by Tem temperature alternating stresses, Ab flattening of the tension structure due to defects, Do tations and crystal boundaries or crystal structure and the resulting bandgap flattening gene.

The method according to the invention can also be used for tempering rature optimization when using solar cells as with Air distance provided heat insulation, where those in the space between the solar module and the so covered heat generated to insulate walls is used, e.g. B. also using cooling rib pen.

Those contained in claims 4 to 10 Features improve the efficiency of the combined Generation of electrical heat energy - also under too additional use of such elements for heat insulation tion. The z. B. round, elliptical or polygonal electrodes for both guiding the photovol taisch generated electricity as well as to conduct a cooling liquid (e.g. water with additives or other lower boiling liquids), as well as Support frame for the construction (also e.g. by An Bringing cooling fins to improve the heat transfer ganges) and enlarge the amount of light  set surface of the photovol attached to it taische layers with improved rigidity. Also coaxial double-walled pipes in which the cooler cooling liquid is fed separately in countercurrent, is within the scope of the invention.

The wall of the electrodes of the solar cell elements te, e.g. B. the radially inner part thereof, may be preferred wise also from an isolating eventl. elastic flexible material exist, the radially outer upper surface with a metallic conductive coating, preferred also with a radially outward reflecting Surface is coated on which the photovol taisch effective layer z. B. from appropriately doped Silicon is attached.

The heat transfer medium or liquid Coolant from the photovoltaic and heat absorption area dissipated heat energy is z. B. usable via heat pumps.

The from the heat pump to the coolant system or the coolant or heat transfer fluid under simultaneous cooling and temperature regulation of the Solar modules according to the invention extracted heat energy contains at the same time

• a) caused by the sun's rays on the Solar modules and their surrounding parts developed heat,  
• b) by the ohmic resistance losses of the photovoltaic electricity Warmth,
• c) that from within the solar cells Current resistance and recombination of emerging photovoltaic charge carriers Heat (which reduces efficiency) and
• d) where appropriate from the environment e.g. B. air flow, rain etc. from the Heat transfer fluid absorbed Thermal energy for that too Temperature difference between the Environmental outside temperature and possibly inside of the solar module system lower temperature the coolant can be used.

To this extent, the entire solar module system can be invented according to the invention, so to speak, also as an outdoor air heat exchanger with a decisive improvement in the overall effect degrees are used. Such an inventive The use of an entire solar module system is not used only the improvement of the overall efficiency, son also increase the output of photovol electrical energy, which is also the easiest is transportable over longer distances.

So it is also advantageous if for the invent liquid-cooled system according to the invention all known Characteristics (high vacuum pipes etc.) of the Thermo-Solar-Ener casting are used so that this energy  can be used instead of electricity for auxiliary functions can.

The invention is set forth below game described in more detail.

The photovoltaic solar cell 1 shown schematically in Fig. 1, consists of tubes 13 made of metal or metallically coated material and form as electrically conductive, the electrode 6 of the photovoltaic solar cell 1 , on the radially outer upper surface of a photovoltaic layer 14 made of z . B. p- and n-doped, especially mono- or polycrystalline silicon.

In the left in Fig. 1, tangentially longitudinally adjacent pair of solar cell elements 3 , the layer of radially superimposed layers ent opposite doped photovoltaic material, ie a z. B. n-doped layer 15 and a p-doped layer 16 , which is in close contact along a contact region 17 with the n-doped layer 15 above the p-doped layer 16 on the adjacent tube 13 . This creates a tandem double solar cell voltage. The cooling liquid 4 flows through the tubes 13 and holds the solar cell elements 3 at the desired low working temperature.

In the solar cell element 3 shown at the right in FIG. 1, only a simple photovoltaic layer 14 is provided, which is constructed either as a p- or n-doped layer 15 or 16 and with an inversely doped th along the contact region 17 Layer 16 or 15 of an adjacent solar cell element 3 (not shown ) is in electrically conductive contact.

The pipes 13 , which function as electrodes 6 and 7 in double functions, are electrically connected by means of electrical lines 18 (+) and 19 (-).

On the light irradiation 20 opposite side of a front of solar cells 1 and solar modules 2 mirror or light-reflecting elements 12 may be provided on which the light beams 20 of al l sides to the photovoltaic layer 14 of the So larzelle reflected 1 and also reflected back .

In Fig. 2, an electrically flattened tube 8 with cooling channel 8 is shown, which with its radially outer n-doped layer 15 of photovoltaic material on a p-doped layer 16 on a plate-shaped base 5 , which in turn is flat with egg ner consisting of n- and p-doped layer 14 is coated. In this case, only the tubes 13 , cooled by means of cooling channel 8 and cooling liquid, form the minus electrode, while the plate-shaped base 5 , the respective other (+) - electrode 6 and 7 , respectively, which is connected to the electrical connecting lines 18 (+ ) and 19 (-) are connected.

In Fig. 3, similar to that in Fig. 1, left, a few solar cell elements 3 are shown, which are cooled via cooling channels 8 with their photovoltaic layer 14 electrically conductive with a metallic plate-shaped base 5 as a counter electrode 7 electrically connected is. Since the p- and n-doped days 15 and 16 these solar cell elements 3 are arranged identically, they do not need to touch each other (as indicated by arrangement 21 ). Its tubes 13 form the one electrode 6 , which is connected to the electrical line 19 (-). For the other pole to the electrical line 18 , the photovoltaic layer 14 with its outer doped layer 16 (or 15 ) with heat and electrically conductive adhesive 9 with the plate-shaped base 5 electrically connected ver, which forms the second electrode 7 . Apart from the cooling through the cooling channels 8 , the cooling of the front of solar modules 2 can also be supplemented by the fact that the plate-shaped base 5 separates ge, z. B. is additionally cooled on the opposite side of the solar modules 2 .

Fig. 4 shows an arrangement of solar modules 2 on a base 5 made of double plates 24 with an intermediate coolant gap 23 , which is attached by an insulating air gap 26 at a distance from a wall 27 (z. B. a house wall), where the air in Air gap over heat-conducting fins 25 can be influenced in terms of temperature, ie can be heated or cooled from the front of solar modules 2 , in particular also due to heating from light radiation 22 of light radiation 20 falling through the front of solar modules 2 .

In the embodiment modified according to FIG. 5, the solar modules 2 with their solar cell elements 3 are inside a transparent plate 28 , for. B. glass or plexiglass plate 28 is arranged, which is mounted at a distance from a wall 27 through the air gap 26 , which can also serve as a coolant gap 23 with liquid coolant. This wall 27 may at its solar modules 2-facing surface mirror or light-reflecting elements 12, and a Ver exhibit reflection, is reflected by means of the falling through the front of solar modules 2 light irradiation 22 on the rear side thereof. The inside of the transparent plate 28 can also have refractive, light-reflecting or light-diffusing elements (eg reflective tinsel).

Similar to the cooling of the solar cell modules 2 by air currents according to FIGS. 4 and 5, the solar cells can also be cooled in that they themselves are moved relatively to the air. If, for example, the cylindrical surfaces of a Savonius wind turbine, for example the outside thereof, are provided with solar cell modules 2 , mechanical energy is generated on the one hand by the wind rotation of the Savonius wind turbine and, on the other hand, the solar cell modules 2 exposed to the light radiation are cooled on the one hand by the air flow and In addition, the strongest light is constantly exposed to the "shadow side", whereby the Demper effect can be exploited.

The schematic representation according to FIGS. 6 and 7 shows an arrangement of a front of photovoltaically coated, coolant-flowed tubes 13 , which each form the one electrode of a solar cell 1 , which is connected to the line 18 (+ pole), while the other electrode is connected via busbar 31 to the other line 19 (pole). The tubes 13 used for this are shown in FIG. 8 and - enlarged - in FIG. 9 in cross-section: the actual, through its channel 8 with coolant through flowing tube 13 made of electrically highly conductive material (e.g. copper) is surrounded by solar cell elements 3 . These have a core or a core which also consists of a material which is also a good electrical conductor (e.g. Cu) and which forms the other electrode 7 . This is surrounded by a photovoltaic layer 14 made of p-doped and n-doped layer, of which the outer one in each case is connected to the outer surface of the tube 13 using heat- and electrically conductive adhesive 9 , or in another way electrically conductive. Depending on the end region of the tube 13 , the electrodes 7 are connected to a busbar 31 on which the electrical line 19 of the (-) pole is located.

Those in FIG. 10 schematically in cross section Darge presented roof structure 32, having in conventional manner un behind the other arranged individual tiles 33 provided with elongate solar modules 2, which, as described above, analogous to FIG. 8 and constructed 9 and traversed by coolant as tubes 13 are formed. This from long, solar element-equipped tubes 13 or a twisted from wire-shaped solar cell elements 3 rope-like solar modules 2 , are via a heat collecting tube 30 at the ridge connection 34 of the roof structure 32 both in terms of cooling water and electrically as an electrode with the electrical (+ ) -Pole line 18 and also connected to the electrical (-) - pole line 19 by means of busbars 31 . The elongated solar modules 2 are shown in FIG. 11 as a plan view of a series of roof tiles 33 in their undulating depressions 35 , as shown in cross-section from FIG. 12. Thus, the solar modules 2 do not require any special elevation and can be easily replaced by quick connections on the ridge connection 34 . In addition, the concave-like, wavy recess 35 of the usual roof tiles for attaching a mirror-like device 36 , z. B. in the form of mirrored Dachzie gels 36 or between roof tiles and solar module 2 brought metalized sheet can be used.

In Fig. 13 shows the cross sectional view of two pol or charge moderately cooperating solar cell elements 3, which are forced against each other within the recess 35. In the sense of the invention, it is when the electrically conductive electrodes 6 and 7 by means of liquid channels. are water cooled.

In FIGS. 11 and 12, lower end of the elongate solar modules 3 may at its lower end of the respective tube 13, z. B. end in the gutter, in which they can also have an energy effect (e.g. thawing or energy from rain).

The flow of solar fluid through the solar cell system is absorbed heat on be known way from a heat pump to a heat circuit dissipated and used as thermal energy. Here the temperature in the circuit through the cooling pipes the solar cell system on for the photovoltaic Optimal chilled temperature set and in if necessary tolerable small deviations constant ge hold. In contrast, the warmth gained is depending on the heat quantity can be withdrawn from the cooling circuit or got to. As a coolant in the cooling tubes of the solar cells is preferably a common, low-boiling and frost-proof material such as B. NH₃. The deprived warmth energy can, possibly also using the heat pipe ef effect to power the heat pump and the circulation pump can be used to trans as much as possible easily portable energy, namely electrical energy, free to win.  

From this point of view, the use of heat engine powered by cheap fuel for mechanical energy.

Reference list

1 photovoltaic solar cell
2 solar modules
3 solar cell elements
4 coolant or coolant
5 plate-shaped underlay
6 elongated electrodes
7 counter electrodes
8 channel
9 heat and electrically conductive adhesive (cold / heat machine)
10 back of the
11 solar cell front
12 mirror or light reflecting elements
13 tubes
14 photovoltaic layer
15 n-doped layer
16 p-doped layer
17 contact area
18 electr. Head (+)
19 electr. Management (-)
20 light exposure
21 arrangement
22 transmitted light radiation
23 coolant gap
24 double plate
25 thermal fins
26 air gap
27 wall z. B. house wall
28 transparent plate, e.g. B. glass or plexiglass plate
30 heat collection tubes
31 busbar
32 roof construction
33 roof tiles
34 ridge connection
35 wavy depressions
36 mirror-like furnishings

Claims (10)

1. A method for the photovoltaic production of electricity by means of solar cells or for the operation of photovoltaic solar modules, characterized in that the photovoltaic solar cell elements by means of coolants, such as. B. air or wind, or preferably liquid or gaseous coolants or regulated by movement temperature, preferably cooled. 2. The method according to claim 1, characterized records that the heat dissipated given cooling if necessary by means of cooling / heating machines, e.g. B. heat pump pen is used for heating purposes. 3. The method according to claim 1, characterized records that the photovoltaic solar cell elements in the event of rapid infestation or icing, and preferably from self-generation from the So lar cell elements. 4. Device for performing the method according to any one of the preceding claims, characterized in that photovoltaic solar cells ( 1 ) are arranged in physical contact, ie on or within a plate-shaped base ( 5 ), which is temperature-controlled. 5. The device according to claim 4, characterized in that the plate-shaped base ( 5 ) is gas or air or liquid-cooled. 6. Device in particular for performing the method according to any one of the preceding claims measures photovoltaic solar cell elements in the form of elongated electrodes with a photovoltaically active coating, characterized in that the solar cell elements ( 3 ) in contact, ie on or within a plate-shaped base ( 5 ) arranged and temperature-controlled. 7. Device for performing the method according to one of claims 1 to 3, characterized in that the electrodes ( 6 ) of the photovoltaic solar cells ( 1 ) tubular or with a coaxial-centric channel's ( 8 ) for passage of a heat transfer medium , e.g. B. a cooling liquid ( 4 ) is provided. 8. Device according to one of the preceding claims, characterized in that the solar cell elements ( 3 ) by means of thermally conductive adhesive ( 9 ) on each other or on the plate-shaped base ( 5 ) be fastened. 9. Device according to one of the preceding claims 4 to 8, characterized by a cooling / heating machine, for. B. a heat pump for utilizing egg nes excess heat of the liquid heat-transferring, temperature-controlling medium ( 4 ) is provided in the heat circuit. 10. Device according to one of the preceding claims, characterized in that on the back ( 10 ) of the temperature-controlled solar cell front ( 11 ) mirror or light reflecting elements are provided, which result from the back light and heat energy to the temperature-controlled solar cells ( 1 ) emits.