System for obtaining renewable energy

Abstract

The invention relates to a system (10) for obtaining renewable energy, which comprises photovoltaic modules (14.1, 14.2) and a support structure (12) for the photovoltaic modules (14.1, 14.2). The support structure (12) encloses a space (18) and together with the photovoltaic modules (14.1, 14.2) forms outer walls (16) of the enclosed space (18), the surface normals of which, defined by the photovoltaic modules (14.1, 14.2), point in at least three different directions. The photovoltaic modules (14.1, 14.2) are fastened to the support structure (12) in such a manner that the photovoltaic modules (14.1, 14.2) can be cooled by an air stream on their rear side pointing to the inside of the enclosed space (18).

Description

[0001] Plant for generating renewable energy

[0002] The invention relates to a plant for generating renewable energy, in particular for generating electrical power from sunlight.

[0003] Renewable energy systems come in many different forms. Examples include wind turbines and photovoltaic systems, as well as solar thermal systems for generating heat from sunlight and geothermal systems for extracting heat from the ground.

[0004] Photovoltaic systems typically comprise an array of photovoltaic modules, which in turn are composed of solar cells. The surface of the photovoltaic modules formed by the solar cells is typically flat and enclosed by a frame. Photovoltaic modules are often mounted on roofs on frameworks in open-air systems. For example, DE 20 2022 002 406 U1 discloses a greenhouse in which the wall and / or roof consist, at least in part, of plate-shaped photovoltaic thermal collectors (PVT collectors). Photovoltaic thermal collectors are assemblies of plates made of a light-transparent material with solar cells and media-carrying lines.

[0005] The invention is based on the object of creating a system for generating renewable energy that is suitable for installation in a limited area. According to the invention, this object is achieved by a system for generating renewable energy that comprises photovoltaic modules and a supporting structure for the photovoltaic modules. The supporting structure encloses a room and, together with the photovoltaic modules, forms at least six, preferably eight or more outer walls that define an at least hexagonal, preferably octagonal or polygonal floor plan of the enclosed room. The surface normals defined by the photovoltaic modules on the outer walls point in at least six, preferably eight or more different directions defined by the at least hexagonal, preferably octagonal or polygonal floor plan. The individual angles are ideally identical; a 10-sided corner, for example, has36 degrees changed direction to the neighbor and the total of the alignment of all photovoltaic modules 360°, A spherical arrangement of the <Photovoltaikmodule wäre diesbezüglich optimal. Die Photovoltaikmodule sind außerdem derart an der Tragkonstruktion befestigt, dass die Photovoltaikmodule auf ihrer zum Inneren des umschlossenen Raums weisenden Rückseite derart hinterlüftet sind, dass sie von einem Luftstrom gekühlt werden können.

[0006] The photovoltaic modules are provided on all exterior walls – i.e., on all sides. Preferably, each exterior wall is formed or covered by at least 80% photovoltaic modules, i.e., all exterior walls preferably carry the same number of (similar) photovoltaic modules. This is advantageous in view of the desired approximately constant output power over many hours of a day.

[0007] While photovoltaic modules in open-air systems can be optimally aligned to the sun and, if necessary, even tracked, the orientation on rooftops is largely determined by the orientation of the respective roof surface or facade. The yield that can be achieved with a photovoltaic system depends, among other things, on the orientation of its photovoltaic modules. With photovoltaic modules aligned in the same direction, the photovoltaic modules deliver maximum electrical output precisely when the solar radiation is at the smallest angle to the surface normal of the photovoltaic modules—i.e., exactly once a day.

[0008] However, with the system for generating renewable energy according to the invention, the electrical power generated by the photovoltaic modules remains approximately constant over several hours of a day because the photovoltaic modules—more precisely, their surface normals—are oriented in at least six different directions. As a result, the area of ​​the system according to the invention directly illuminated throughout the day is almost constant throughout the day because the outer walls of the system for generating renewable energy according to the invention, with their photovoltaic modules, form a versatile prism that approximates a cylindrical shape.

[0009] This represents a departure from conventional designs because the inventive system for generating renewable energy also features north-facing photovoltaic modules, which are barely exposed to direct sunlight and therefore produce a comparatively low yield. However, the less productive photovoltaic modules mean that the inventive system for generating renewable energy delivers an almost constant output over a significant portion of a day, despite the changing direction of sunlight and the changing position of the sun. This is also due to the preferred vertical orientation of the exterior walls, which represents a departure from the otherwise preferred 35° orientation and results in the light from the low-lying sun in the morning and evening being better utilized than the light from the sun at midday.

[0010] The all-round arrangement of the photovoltaic modules has the advantage that a portion of the direct solar radiation falls on a nearly constant, equally large, directly illuminated area of ​​the photovoltaic modules of the inventive system for generating renewable energy over the course of the day, i.e., when the sun's azimuth varies depending on the time of day. By combining side walls formed by photovoltaic modules in a cylinder-like arrangement (e.g., 6-cornered) with photovoltaic modules in a conical-like arrangement as a type of roof above the side walls (without projecting laterally beyond the side walls), a nearly constant, consistent total output power supplied by the photovoltaic modules is achieved over the course of the day, even when the sun's altitude changes depending on the time of day.North-facing photovoltaic modules in German and Central European latitudes receive direct sunlight only in the morning and evening hours in summer, and no direct radiation at all in spring, autumn, and winter. In typical Central European regions between 40° and 60° north latitude, sunshine hours are between approximately 20% and 40% of the theoretical maximum of 4380 hours per year. 4380 hours is half of 8760 hours, i.e., day / night. Conversely, this means that the sky is overcast 80% to 60% of the days per year. Due to the absorption and reflection effects of the atmosphere and the resulting emission of the atmosphere (radiation), the atmosphere itself becomes a radiation source. This is also known as diffuse radiation; it is isotropic mainly on overcast days, meaning it is non-directional and the entire hemisphere (half of a sphere) radiates.This diffuse radiation is received equally by all photovoltaic modules, and thus even photovoltaic modules facing away from the sun in winter are able to make the same contribution as south-facing modules. The sum of direct and diffuse radiation is the total radiation, and it is precisely this utilization that is maximized by the present invention for the maximum possible annual yield when utilizing diffuse radiation through all-round module alignment (the entire hemisphere emits diffuse radiation). To utilize direct solar radiation, the sun varies in two variables throughout the day: the solar azimuth (compass direction) and the solar altitude (at midday at the zenith). The described geometry of the arrangement of the photovoltaic modules in the present invention makes it possible to provide a consistently large area of ​​direct sunlight throughout the day on cloudless, sunny days.The photovoltaic output is thus almost constant throughout the day and at the summer solstice, 16 to 18 hours of direct use in one day are possible in Europe.

[0011] The almost constant output power over as long a part of the day as possible means that the output power can be used more efficiently because all electrical consumers and the inverters do not have to be designed in relation to the possible peak power of all photovoltaic modules taken together, but rather to the total power of the system according to the invention for generating renewable energy, which results from the non-optimal orientation of many photovoltaic modules and which is relatively constant over many hours of a given day.

[0012] This results in further advantages, such as a higher direct usage share of the generated electricity, since the required power is available over a larger portion of the day and thus over a longer period. If the generated electrical power is used, for example, to operate an electrolyzer, this results in more full operating hours, i.e., operating hours at maximum or rated power. This means less electricity needs to be fed into the grid or stored, since less surplus is produced at peak times, but the required power is available and can be fully utilized over a longer period of the day.

[0013] A beneficial consequence is that inverters or DC-DC converters only need to be designed for a maximum of 40% of the peak power of the photovoltaic modules. Therefore, a renewable energy generation system is preferred that includes one or more inverters electrically connected to the photovoltaic modules and that, taken together, are designed for an electrical output that is less than 50% of the peak electrical output of all photovoltaic modules combined.

[0014] By utilizing diffuse irradiation, the yield is significantly higher than that achieved with a photovoltaic system of the same footprint using tracking photovoltaic modules ("movers"), since the total area of ​​the photovoltaic modules in the system according to the invention for generating renewable energy is larger than in a photovoltaic system with tracking photovoltaic modules. In a photovoltaic system with tracking photovoltaic modules, the photovoltaic modules are arranged in such a way that they do not shade each other and are therefore spaced horizontally apart.The system for generating renewable energy according to the invention can even achieve an annual yield that is more than twice as high as that of a photovoltaic system with tracking photovoltaic modules, which is due to the proportion of diffuse radiation that a photovoltaic system with tracking photovoltaic modules cannot utilize to any significant extent due to the small active photovoltaic module area.

[0015] This is possible because for the system for generating renewable energy according to the invention, the radiation-receiving area of ​​all photovoltaic modules available for photovoltaics is approximately 4 to 5 times larger than the base area of ​​the system for generating renewable energy according to the invention.

[0016] The plant according to the invention for generating renewable energy thus offers two main advantages over known photovoltaic systems: firstly, electrical energy can be generated with a significantly higher area-specific yield (relative to the base area of ​​the plant according to the invention for generating renewable energy) and secondly, this energy can be generated very continuously, i.e. with uniform power, on sunny days, relative to the course of a day.

[0017] In order to achieve such a constant course of the generated electrical power, it is particularly advantageous if the side walls of the supporting structure are vertical and at least approximately form a cylinder and if a preferably provided roof structure with photovoltaic modules forms a cone or truncated cone with an almost circular cross-section. If there is a hole in the apex of the cone for a wind turbine, then the overall daily course of the generated electrical power can be "adjusted" to a horizontal level by the angle of inclination of the photovoltaic modules in the apex of the cone (i.e. the roof structure), i.e. an approximately constant output can be achieved. According to the invention, the supporting structure together with the photovoltaic modules forms at least six, preferably eight or more outer walls which define an at least hexagonal, preferably octagonal or polygonal floor plan of the enclosed space.The floor plan preferably has the shape of a regular polygon and is therefore close to the shape of a cylinder.

[0018] The ratio of the height of the exterior walls - preferably without the inclined photovoltaic modules of a roof structure - to the diameter of the floor plan is preferably between 0.75 and 1.25. This ratio is particularly advantageous in combination with a roof structure equipped with photovoltaic modules because it results in the desired, almost constant output power over several hours of a day, since the photovoltaic modules of the roof structure compensate for a reduced output power of the other photovoltaic modules when the sun is very high in the sky at midday in summer.

[0019] Preferably, the exterior walls that define the floor plan of the enclosed space are vertical, rectangular and adjacent to each other.

[0020] According to one embodiment, the outer walls define a floor plan with a maximum outer diameter of less than 5m, preferably less than 4m.

[0021] Preferably, the supporting structure comprises a roof structure that supports inclined photovoltaic modules that are oriented in different directions.

[0022] In a particularly preferred embodiment, the system comprises an air-source heat pump, which, during operation, is fed by air flowing along the inside of the photovoltaic modules, cooling and thus preheating them. In such a system, the air-source heat pump can be operated with a particularly favorable COP (Coefficient of Performance), so that a comparatively large amount of heat can be generated with the electricity driving the air-source heat pump. The heat output delivered by the air-source heat pump can, for example, correspond to four to five times the electrical power required to drive the air-source heat pump. "Air-source heat pump" here refers to all heat pumps that use air as a heat source and includes all air-source heat pumps, such as monoblock and split designs.Preferably, the outer walls are provided with air ducts, for example flow channels, for rear ventilation of the photovoltaic modules, which are arranged and configured such that air is guided counter to the convection direction along the back of the photovoltaic modules and to the air heat pump.

[0023] The movement of the air against the direction of convection is preferably caused by a fan or blower of the air heat pump.

[0024] Taking into account the higher efficiency of the photovoltaic modules caused by the cooling, the following picture emerges:

[0025] The additional yield achieved by cooling the photovoltaic modules exceeds the power required to operate the fan for heat pump operation (e.g. 1.2 kWh), or pure cooling mode with reduced fan speed (0.5 kWh). The significantly greater benefit, however, is the additional heat energy that can be made available to the heat pump for domestic water heating in summer. This additional usable heat energy leads to a reduction in the electrical energy required to operate the heat pump with a constant heat demand. The additional usable heat energy results from the air preheated by cooling the photovoltaic modules. A photovoltaic module cooled according to the invention has an annual increase in electricity yield of typically 5% to 10% compared to a system without photovoltaic modules cooled by ambient air.The electrical requirement of the fan, which is necessary to generate the forced flow, is ideally speed-controlled and operated in accordance with the cooling effect, unless the heat pump has an increased current heating requirement (e.g. hot water).

[0026] For example, an apartment building with 48 residential units has an average hot water energy demand of 550 kWh_th per day in summer. Providing this heat energy with a COP of 4 would require 137.5 kWh_el. By additionally utilizing the waste heat from photovoltaic modules, the COP can be increased to an average of approximately 5. Thus, only 110 kWh_el are required to cover the hot water energy demand. This value also roughly corresponds to the daily yield of a renewable energy generation system according to the invention.

[0027] In principle, this results in a COP increase of at least 1.0 throughout the year—and even 1.3 in winter. The annual performance factor of a heat pump in a renewable energy generation system according to the invention thus reaches values ​​comparable to those of a brine heat pump.

[0028] Preferably, the air heat pump is electrically connected to the photovoltaic modules in such a way that the air heat pump can be operated using electricity generated by the photovoltaic modules. Due to the particularly favorable COP of the air heat pump in the proposed configuration, this results in a system that can provide heat particularly efficiently.

[0029] According to an alternative embodiment, a gas storage unit, namely a pressureless hydrogen or oxygen storage unit, is arranged within the space enclosed by the outer walls. In this variant, the system preferably comprises an electrolyzer for generating hydrogen using photovoltaically generated electricity, which can be stored in the gas storage unit. Such a system allows the photovoltaically generated electricity to be used even when there is no immediate need for the electricity. Furthermore, using the generated hydrogen, for example with the help of a fuel cell, electricity can be generated and supplied even when photovoltaics cannot supply any or insufficient electrical power, e.g., on winter days.

[0030] For the operation of the electrolyzer, it is particularly advantageous that the system for generating renewable energy according to the invention delivers an approximately constant electrical output power over many hours of the day. The system for generating renewable energy according to the invention can be designed in conjunction with an electrolyzer such that the power requirement of the electrolyzer during optimal operation corresponds to the approximately constant electrical output power of the system for generating renewable energy according to the invention over many hours of the day. This allows the electrolyzer to be operated at approximately 3,000 full-load hours per year, whereas conventional photovoltaic systems in conjunction with an electrolyzer only operate at approximately 1,000 full-load hours per year.

[0031] A further advantageous aspect is that the recirculation of the pressureless hydrogen storage system by means of air directed along the inside of the photovoltaic modules to cool them increases the safety of the operation of the pressureless hydrogen storage system because any hydrogen escaping through leaks is inevitably diluted to such an extent that it can be easily detected, thus eliminating any danger. A system comprising a supporting structure of the type described here and attached photovoltaic modules, as well as a gas storage system and an electrolyzer, represents an independent inventive concept that can also be implemented independently of other aspects described here, such as air cooling of the photovoltaic modules.

[0032] According to this independent inventive concept, a system for generating renewable energy is provided which comprises photovoltaic modules and a support structure for the photovoltaic modules, wherein the support structure encloses a space and, together with the photovoltaic modules, forms outer walls of the enclosed space, the surface normals of which, defined by the photovoltaic modules, point in at least three different directions. A gas storage unit is arranged in the enclosed space, and the system comprises an electrolyzer which is electrically connected to the photovoltaic modules in such a way that the electrolyzer is to be operated with electrical current generated by the photovoltaic modules and generates hydrogen during operation. The gas storage unit is preferably enclosed in a flexible, gas-tight envelope like a balloon and thus has a variable internal volume which, during operation, is completely filled with hydrogen or oxygen.

[0033] If three similar systems according to the invention for generating renewable energy are set up at one location, it can be advantageous for reasons of efficiency and service life to use two of the systems with a hydrogen storage unit and one of the systems with an oxygen storage unit. In this way, a fuel cell can be operated with pure oxygen during re-electrification, resulting in increased efficiency, more gentle operation, and a longer service life than when using ambient air with its potential contaminants, e.g. active harmful gases such as carbon monoxide, sulfur dioxide, or other catalyst-damaging gases. Preferably, a system comprising at least one hydrogen storage unit and at least one oxygen storage unit is equipped with an electrolyzer that produces hydrogen and oxygen simultaneously. The electrolysis of water produces two parts hydrogen (H2) and one part oxygen (O2).Therefore, hydrogen storage capacity is preferably twice that of oxygen. The latter can be achieved by providing three similar renewable energy generation systems according to the invention at one location, two of which are equipped with a hydrogen storage unit and one with an oxygen storage unit. In a further embodiment, the system comprises a wind turbine with a mast extending through the center of the space enclosed by the outer walls.Preferably, the mast of the wind turbine is a telescopic mast, with the aid of which the wind turbine can optionally assume a retracted state, in which the wind turbine is located within the space enclosed by the outer walls and, if applicable, a roof structure, and an extended state, in which the wind turbine is located outside the space enclosed by the outer walls and, if applicable, a roof structure. The invention will now be explained in more detail using exemplary embodiments with reference to the figures. The figures show:

[0034] Figure 1a: a side view of a plant according to the invention for generating renewable energy with an extended wind turbine;

[0035] Figure 1 b: a side view of a plant according to the invention for generating renewable energy with retracted wind turbine;

[0036] Figure 1c: a perspective view of the plant according to the invention for generating renewable energy from Figures 1a and 1b;

[0037] Figure 2a: a side view of an alternative system according to the invention for

[0038] Generating renewable energy;

[0039] Figure 2b: a plan view of the plant according to the invention for generating renewable energy according to Figure 2a;

[0040] Figure 2c: a perspective view of a system according to the invention for

[0041] Generating renewable energy according to Figures 2a and 2b;

[0042] Figure 3a - d: Diagrams illustrating a typical curve of the generated electrical power over different sunny days;

[0043] Figure 4. an enlarged view of the diagram in Figure 3d;

[0044] Figure 5: a perspective view of a system according to the invention for

[0045] Generating renewable energy in a perspective view; Figure 6: an alternative system according to the invention for generating renewable energy in a perspective view;

[0046] Figures 7a, b: two side views of the renewable energy generation plant corresponding to Figures 1a and 1b;

[0047] Figures 8a, b: two perspective views of a system with a wind turbine and a photovoltaic system;

[0048] Figure 9: a schematic representation of a system according to the invention for

[0049] Generating renewable energy with air ducts for rear ventilation and cooling of the photovoltaic modules with air and a heat pump to which the air preheated by cooling the photovoltaic modules is fed through the air ducts.

[0050] Figures 10a, b: two diagrams illustrating ventilation of photovoltaic modules in combination with an air heat pump;

[0051] Figures 11 a, b: two further representations to illustrate the rear ventilation of the photovoltaic modules;

[0052] Figures 12a, b: two side views of two different plants according to the invention for generating renewable energy with integrated gas storage.

[0053] A system 10 according to the invention for generating renewable energy has a supporting structure 12 with photovoltaic modules 14 attached thereto. The supporting structure 12 with the photovoltaic modules 14.1 forms outer walls 16 that enclose a space 18. The outer walls 16 are vertical and define a polygonal floor plan. In the examples shown in Figures 1a, b, and c and Figures 2a, b, and c, a total of ten laterally adjacent, vertically standing outer walls 16 are provided, which define an overall decagonal floor plan. Each outer wall 16 is formed by a corresponding supporting structure 12 and two photovoltaic modules 14 arranged one above the other. In addition, the supporting structure 12 also forms a roof structure 20 that supports a total of five inclined photovoltaic modules 14.2.The supporting structure 12, including the roof structure 20 and the photovoltaic modules attached to the supporting structure 12 and the roof structure 20, enclose the space 18 such that, according to preferred embodiments, an air heat pump 22 can be arranged in the enclosed space 18. The number of photovoltaic modules 14 shown in the example is a typical embodiment and depends on the dimensions and / or space requirements at the installation site.

[0054] In order to enable a maximum output that fluctuates only slightly over preferably several hours of a day (see also Figures 3a to 3d and Figure 4), it is advantageous if the side walls with the photovoltaic modules 14.1 form a regular prism, i.e. a straight prism with a regular polygon as its base. However, providing photovoltaic modules 14.1 solely on the side walls of such a prism would lead to a drop in the generated electrical power at high altitudes around midday; therefore, the inclined photovoltaic modules 14.2 are preferably provided on the top side of the prism. The inclined photovoltaic modules 14.2 are preferably inclined at an angle of between 30° and 60° to the vertical.

[0055] The height of the side walls - these are the outer walls 16 - preferably corresponds approximately to the diameter of the floor plan, for example between 0.75 and 1.25 times the diameter of the floor plan.

[0056] In addition, a mast 24 for a wind turbine 26 (Figures 1a and 1b) or 26' (Figures 2a and 2b) can also be provided in the center of the enclosed space. The wind turbine 26 or 26' is attached to the mast 24 or 24' in such a way that the wind turbine 26 or 26' can be moved up and down along the mast 24 or 24', so that the wind turbine 26 can assume a retracted position and an extended position. For this purpose, the mast 24 or 24' can be a telescopic mast. In the retracted position, the wind turbine 26 or 26' is located in the enclosed space 18, while in its extended state the wind turbine 26 or 26' is located above the roof structure 20. As can be seen from Figures 1a, b and c and Figures 2a, b and c, the roof structure 20 encloses a central opening 28 through which the wind turbine 26 or 26' can be extended and retracted.Figure 7a shows the wind turbine 26 in the extended state and Figure 7b shows the wind turbine 26 in the retracted state.

[0057] Figure 5 illustrates a system 10 according to the invention for generating renewable energy, in which the supporting structure 12 carries the roof structure 20 with a total of five inclined photovoltaic modules 14.2, which enclose the central opening 28 through which the wind turbine 26 or 26' can be extended and retracted.

[0058] If no wind turbine is provided, a roof structure 20' may also be provided which does not enclose a central opening, but is formed, for example, by six photovoltaic modules 14.2, as shown in Figure 6.

[0059] As can be seen in particular from Figure 2a, the floor plan defined by the walls 16 results in the outer surfaces of the photovoltaic modules 14.1 being oriented in practically all directions. The decagonal floor plan is almost circular. The orientation of the photovoltaic modules 14.1 in all directions means that the electrical power generated over the course of a sunny day does not have a single narrow maximum around midday, but remains almost consistently high over several hours, for example, over eight hours. This is illustrated in Figures 3a to 3d and Figure 4. The lower curve shows a typical curve of the electrical power generated over a day when the power is generated by photovoltaic modules that are all oriented towards the south (and tilted by 35° in the example). In this case, the highest electrical power is generated around midday.As the angle of incidence of the sun changes throughout the day, the electrical power generated by the photovoltaic modules aligned in this way also changes.

[0060] The inventive arrangement of the photovoltaic modules on vertical walls along an approximately circular layout—more precisely, along a layout in the shape of a regular polygon—in combination with the inclined photovoltaic modules 14.2 of the roof structure 20, results in different photovoltaic modules delivering their respective maximum electrical output at different times of day, depending on the changing angle of the sun's incidence throughout the day. This results in the approximately consistent output over the course of several hours, as shown in Figures 3a to 3d and Figure 4.

[0061] The number of photovoltaic modules 14.1 on the side walls 16 and the number of photovoltaic modules 14.2 on the roof structure 20 also depends on the size of the renewable energy generation system 10. Typical sizes can be, for example, the following: 3.5 m diameter of the floor plan; the photovoltaic modules 14.1 and 14.2 have an installed capacity of approximately 10 kWp and, during operation, supply approximately 4 kW of electrical power, for example, over a longer period of a sunny day;

[0062] 11.5 m diameter of the floor plan; the photovoltaic modules 14.1 and 14.2 have an installed capacity of approximately 97.5 kWp and, when in operation, for example, over a longer period of a sunny day, supply approximately 40 kW of electrical power.

[0063] 35 m diameter of the floor plan; the photovoltaic modules 14.1 and 14.2 have an installed capacity of approximately 1100 kWp and, during operation, supply approximately 440 kW of electrical power over a longer period of a sunny day, for example; see also Figures 12a and 12b, which show a system with a gas storage facility for storing hydrogen produced by electrolysis during the solar season.

[0064] Ideally, the renewable energy generation system according to the invention is connected to at least one electrical consumer whose power consumption corresponds to the electrical power supplied by the renewable energy generation system 10. This allows a significant extension of the hours of full renewable solar energy utilization throughout the year, when the sun's equinoctial line is exceeded (between March 21 and September 23), by more than 15% compared to mounted photovoltaic modules or tilted photovoltaic systems on a roof.

[0065] The 26' or 26' wind turbine, which can be extended and retracted using the 24' or 24' telescopic mast, also contributes to the year-round higher yield achieved with the 10 system than with single-sided, elevated photovoltaic modules. A wind turbine typically produces more energy in the winter months than in the sunny summer months. This allows for more potential full-utilization hours of solar and wind energy, especially when combined with photovoltaic modules and air-to-water heat pumps.

[0066] An alternative system 10' for generating renewable energy comprises a wind turbine 26'" with a fixed tower 24'" around the base of which a supporting structure 12' with attached photovoltaic modules 14 is arranged, which is similar to the system 10 for generating renewable energy according to Figures 1 and 2; see Figures 8a and 8b. In the illustrated embodiment, the vertical side walls 16 forming a cylinder can support approximately 2000 modules, and the roof structure forming a truncated cone can support approximately 754 modules that enclose an opening through which the tower 24"' of the wind turbine 26"' projects. As described further below, the supporting structure 12' with the attached photovoltaic modules 14 also encloses an interior space 18, which can be used, for example, to store gaseous hydrogen.

[0067] Another aspect of the system 10 is illustrated in Figures 9, 10 and 11. These show that on the inside of the walls 16 - i.e. on the back of the photovoltaic modules

[0068] 14.1 and 14.2 - rear ventilation is provided for cooling the photovoltaic modules 14.1 and 14.2. For rear ventilation, a rear wall 30 is provided, preferably at a distance that promotes air flow, so that a flow channel 32 is formed between the rear of the photovoltaic modules 14.1 and 14.2 and the rear wall 30. This can be fluidically connected to the heat pump 22. In this way, the heat pump 22 can be operated with preheated air, thus increasing the coefficient of performance (COP) of the heat pump 22. The heat pump is preferably designed as a monoblock or as a split unit variant. At the same time, the efficiency of the photovoltaic modules is avoided.

[0069] 14.1 and 14.2 due to heating of the photovoltaic modules 14.1 and 14.2. To ensure the best possible heat transfer from the back of the photovoltaic modules

[0070] To achieve a uniform distribution of heat between the photovoltaic modules 14.1 and 14.2 and the passing air, air guiding elements are preferably provided in the flow channel 32, which create turbulence in the flowing air. This increases the convective heat transfer coefficient between the photovoltaic modules 14.1 and 14.2 and the passing air.

[0071] The heat pump 22 is an air heat pump with a heat exchanger 22.1 and a fan 22.2

[0072] The rear wall 30 on the backs of photovoltaic modules 14.1 and 14.2 thus enables controlled ventilation of the PV modules. This increases the electrical efficiency while maintaining constant diffuse and direct solar radiation, since photovoltaic modules 14.1 and 14.2 have a PTC characteristic, meaning the electrical (internal) resistance is lower at lower temperatures. Depending on the application, the rear walls 30 can also be thermally insulated.

[0073] In addition, the air is heated by heat transfer. When installing a heat pump 22 with an outdoor unit that uses outside air as the primary source, the air entering the outdoor unit can be preheated at the rear of photovoltaic modules 14.1 and 14.2 before entering the heat pump's evaporator, thereby increasing the efficiency of the heat pump 22 in sunlight / daylight. This enables a reduction in operating time and further energy savings.

[0074] Cooling air on the rear side of photovoltaic modules 14.1 and 14.2 is drawn from top to bottom, counter to the direction of convection. For this purpose, air ducts, e.g., flow channels, are provided on the rear side of photovoltaic modules 14.1 and 14.2, through which the air is guided along the rear side of photovoltaic modules 14.1 and 14.2. The air duct can be formed, for example, by the rear wall 30.

[0075] The additional yield achieved by cooling the photovoltaic modules 14.1 and 14.2 exceeds the power required to operate the fan 22.2 for heat pump operation (e.g. 1.2 kWh), or for pure cooling operation with reduced fan speed (0.5 kWh). The significantly greater benefit, however, is the additional heat energy that can be made available to the heat pump 22 for domestic water heating in summer. This additional usable heat energy leads to a reduction in the electrical energy required to operate the heat pump at a constant heat demand. The additional usable heat energy results from the air preheated by cooling the photovoltaic modules 14.1 and 14.2. According to the example mentioned at the beginning, an apartment building with 48 residential units has an average hot water energy requirement of 550 kWh of heat energy per day in summer.To provide this thermal energy with a COP of 4, 137.5 kWh of electrical energy would be required. By additionally utilizing the waste heat from photovoltaic modules, the COP can be increased to approximately 5 on average. Thus, only 110 kWh of electrical energy are required to cover the hot water energy demand. This value also roughly corresponds to the daily yield of the renewable energy generation system according to the invention.

[0076] In principle, this results in a COP increase of at least 1.0 throughout the year—and even 1.3 in winter. The annual performance factor of a heat pump in a renewable energy generation system according to the invention thus achieves values ​​comparable to those of a brine heat pump. Depending on the application, the photovoltaic modules 14.1 and 14.2 can also be cooled by a fan or blower 34; in this case, the electrical energy consumption should be lower than the additional electrical energy gained through cooling.

[0077] The interior space 18 is versatile; in smaller versions, it can, for example, serve as a storage room for gardening tools, bicycles, or similar everyday items. With monoblock heat pumps, the heat is transferred to the building via well-insulated, usually underground pipes. For well-insulated buildings that receive high levels of solar radiation, such as south-facing windows, intermediate storage in a heat storage unit is recommended to temporarily store the solar energy from electricity to heat for the night or until the next day. If it is not possible to install the heat storage unit inside the building, the interior space 18 can be used for this purpose.

[0078] Larger designs have a larger volume. This volume increases with the cube of doubling the diameter and doubling the height. This makes the volume ideal for storing volatile solar and wind energy. A large volume is ideal for energy storage with hydrogen, which has a low density at normal pressure.

[0079] Due to the large volume, a gas reservoir 36 for hydrogen or oxygen, for example, can also be provided in the interior 18, see Figures 12a and 12b. The gas reservoir 36 is preferably a non-pressurized gas reservoir. For smaller interior spaces 18, the gas reservoir 36 can be a balloon with a small volume, see Figure 8b. For larger storage volumes, the gas reservoir 36 can have a rolling diaphragm that is loaded at the top with a weight plate (see Figure 8a), as can be found in gasometers, for example. Depending on the design, these can then also be found with slight overpressures, but up to a maximum of 50 mbar. Other possible designs for the gas reservoir 36 are telescopic gas containers, bell-shaped gas containers, wet gas containers, disc gas containers, screw gas containers and spherical containers.

[0080] The rolling membrane 38 or the balloon envelope 38' are preferably formed from a gas-tight, flexible material web or film.

[0081] In order to generate hydrogen using the electrical current generated by the photovoltaic modules 14.1 and 14.2, the system 10 is equipped with an electrolyzer 40. This is electrically connected at least indirectly (e.g., via appropriate converter electronics or inverters) to the photovoltaic modules 14.1 and 14.2. Furthermore, the electrolyzer is connected to the interior of the gas storage unit 36 ​​via a gas line (not shown) in order to feed hydrogen generated by the electrolyzer 40 into the gas storage unit 36. The gas storage unit 36 ​​can be connected to a further gas line (also not shown) in order to supply the hydrogen contained in the gas storage unit 36, for example, to a fuel cell or a gas boiler, each of which is typically not an integral part of the system 10.

[0082] Since the gas storage 36 is pressureless and the hydrogen produced by the electrolyzer 40 does not need to be compressed, the electrolyzer 40 is capable of filling the gas storage 36 directly. The design and operating time of the electrolyzer 40 allow the hydrogen production and thus the filling rate of the gas storage 36 to be directly specified. A compressor is not considered because it is not required.

[0083] The system shown in Figures 8a and 8b can also have a pressureless gas storage unit inside, as shown by way of example in Figures 12a and 12b. Hydrogen can be produced and stored without pressure using solar and / or wind energy.

[0084] During periods of low light, electricity can also be generated from stored hydrogen via a fuel cell and then distributed via the local wind transformer into the public grid, industrial grid or even at e-charging stations as 100% renewable energy and used, for example, for recharging (DC).

[0085] Preferably, such a renewable energy generation system is connected to one or more fuel cells, which can preferably provide heat for the buildings in the central heating system, so that not only the electricity generated by the fuel cell and the hydrogen, but also the resulting heat can be used.

[0086] 10, 10' plant for generating renewable energy

[0087] 12, 12' supporting structure

[0088] 14.1 , 14.2 Photovoltaic module

[0089] 16 Wall, side wall

[0090] 18 enclosed space, interior

[0091] 20, 20' roof construction

[0092] 22 air heat pump

[0093] 22.1 Heat exchanger of the air heat pump

[0094] 22.2 Air source heat pump fan

[0095] 24, 24'“ mast, tower, telescopic mast for a wind turbine

[0096] 26, 26', 26'“ wind turbine / wind turbine

[0097] 28 Opening in the roof structure

[0098] 30 rear wall

[0099] 32 flow channel

[0100] 34 Blower, fan

[0101] 36 pressureless gas storage tanks

[0102] 38 gas-tight material web, gas-tight cover

[0103] 38' balloon envelope

[0104] 40 Electrolyzer

Claims

Claims 1. A plant (10) for generating renewable energy, comprising photovoltaic modules (14.1, 14.2) and a supporting structure (12) for the photovoltaic modules (14.1, 14.2), and photovoltaic modules (14.1, 14.2) are fastened to the supporting structure (12) in such a way that the photovoltaic modules (14.1, 14.2) can be cooled by an air flow on their rear side facing the interior of the enclosed space (18). wherein the supporting structure (12) encloses a space (18) and, together with the photovoltaic modules (14.1, 14.2), forms outer walls (16) of the enclosed space (18), characterized in that the supporting structure (12) together with the photovoltaic modules (14.1, 14.2) forms at least six, preferably eight or more outer walls (16) which define an at least hexagonal, preferably octagonal or polygonal floor plan of the enclosed space (18), wherein the solar cells generated by the photovoltaic modules (14.1, 14.2)2) the surface normals defined on the outer walls point in at least six, preferably eight or more different directions defined by the hexagonal, preferably eight or more cornered floor plan.

2. Plant according to claim 1, characterized in that the supporting structure (12) comprises a roof structure (20) which supports inclined photovoltaic modules (14.2) which are oriented in different directions.

3. Installation according to claim 1 or 2, characterized in that the outer walls (16) defining the floor plan of the enclosed space (18) are vertical, adjacent to one another and each rectangular.

4. Installation according to at least one of claims 1 to 3, characterized in that the floor plan formed by the outer walls (16) has the shape of a regular polygon.

5. Plant according to at least one of claims 1 to 4, characterized in that the ratio of the height of the outer walls (16) to the diameter of the floor plan is between 0.75 and 1.

25.

6. System according to at least one of claims 1 to 5, characterized in that the system comprises one or more inverters which are electrically connected to the photovoltaic modules and which are designed for an electrical power which is less than 50% of the peak electrical power of all photovoltaic modules taken together.

7. Plant according to at least one of claims 1 to 6, characterized in that a pressureless hydrogen storage device is arranged within the space (18) enclosed by the outer walls (16).

8. Installation according to at least one of claims 1 to 7, characterized in that the installation (10) comprises a wind turbine (26) having a mast (24) which runs through the center of the space (18) enclosed by the outer walls (16).

9. Installation according to claim 8, characterized in that the mast (24) of the wind turbine (26) is a telescopic mast, with the aid of which the wind turbine (26) can optionally assume a retracted state in which the wind turbine (26) is located within the space (18) enclosed by the outer walls (16) and optionally a roof structure (20), and an extended state in which the wind turbine (26) is located outside the space (18) enclosed by the outer walls (16) and optionally a roof structure (20).

10. System according to at least one of claims 1 to 9, characterized in that the system (10) comprises an air heat pump (22) which, during operation, is fed by air flowing along an inner side of the photovoltaic modules (14.1), cooling the photovoltaic modules (14.1) and thereby preheating them.

11. System according to claim 10, characterized in that the air heat pump (22) is electrically connected to the photovoltaic modules (14.1, 14.2) in such a way that the air heat pump (22) is to be operated with electrical current generated by the photovoltaic modules (14.1, 14.2).

12. System according to at least one of claims 10 or 11, characterized in that the outer walls are provided with air ducts for rear ventilation of the photovoltaic modules, which are arranged and configured in such a way that air against the direction of convection along the back of the photovoltaic modules and to the air heat pump.

13. System according to at least one of claims 10 or 12, characterized in that the movement of the air against the convection direction is effected by a fan of the air heat pump.

14. Plant (10) for generating renewable energy, which comprises photovoltaic modules (14.1, 14.2) and a supporting structure (12) for the photovoltaic modules (14.1, 14.2), characterized in that the supporting structure (12) encloses a space (18) and, together with the photovoltaic modules (14.1, 14.2), forms outer walls (16) of the enclosed space (18), the surface normals of which, defined by the photovoltaic modules (14.1, 14.2), point in at least three different directions, wherein a pressureless hydrogen storage device (36) is arranged in the enclosed space (18) and the plant (10) comprises an electrolyzer (40) which is electrically connected to the photovoltaic modules (14.1, 14.2) in such a way that the electrolyzer (40) is connected to the photovoltaic modules (14.1, 14.2) and produces hydrogen during operation.

15. Plant according to claim 14, characterized in that the pressureless hydrogen storage device (36) is enclosed in a balloon-like manner by a flexible, gas-tight envelope (38) and has a variable internal volume which is completely filled with hydrogen during operation.

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