EP1957878A2

EP1957878A2 - Device and method for the technical utilization of solar power

Info

Publication number: EP1957878A2
Application number: EP06819590A
Authority: EP
Inventors: Volker Tank
Original assignee: Deutsches Zentrum fuer Luft und Raumfahrt eV
Current assignee: Deutsches Zentrum fuer Luft und Raumfahrt eV
Priority date: 2005-12-06
Filing date: 2006-11-17
Publication date: 2008-08-20
Also published as: DE102006042888A1; WO2007065783A3; WO2007065783A2

Abstract

Disclosed is a joint panel device in which photothermal-type panels (61) and photovoltaic-type panels (62) are combined and in which the ratio between photothermal power and photovoltaic power can be varied. For this purpose, the panels are arranged in the form of slats, for example, which can be adjusted like a blind in order to expose one or the other type of panels to solar radiation. Also disclosed is a method for distributing the power of a power supply system to the three types of power consumption, i.e. heating, hot water, and power generation. According to said method, the power supplied is allotted to consumption, storage, or conversion into another type of energy based on a prediction about the temporal availability of the amount of solar power by taking into account weather data and a prediction about the utilization of each of the three types of power consumption based on empirical values in such a way that the utilization ratio is maximized.

Description

Device and method for the technical use of solar energy

The invention relates to a device for the technical use of solar energy, in particular for heating purposes in small systems for heating residential buildings.

The technical use of solar energy is carried out on the one hand with large systems in an industrial setting and on the other hand with small systems in private. Small systems are either photovoltaic to generate electricity or photothermal to produce hot water. The efficiency of converting solar radiation into thermal energy is 60% to 70% when converting into electrical energy 10% to 25% (10% for inexpensive amorphous silicon solar cells, 20 to 25% for expensive, photovoltaic, multilayered gallium arsenide Cells). The price for Acquisition and operation are currently lower for photothermal systems than for photovoltaic ones. Efficiency and costs suggest that the photothermal systems are superior.

The use of the collected energy is considered below for a more precise assessment. To this end, the concept of the efficiency of use is introduced here as the ratio of the energy used to the energy provided by the solar system.

In the case of photovoltaic systems, the provision is completely decoupled from use by the system operator: the electrical energy is fed into the public power grid and is available to all connected users. The system operator includes a financial remuneration. Apart from losses in the line network, the efficiency of use is 100%.

The energy provided by photothermal systems is stored by the system operator in the form of heated water and is only available to the operator himself. The efficiency of their use depends on the optimal adaptation of three influencing factors: the time-varying supply of the sun, the capacity and the losses of the storage and the usage habits of the operator. It is influenced on the one hand by the amount of energy offered / stored and on the other hand by the degree of temporal correspondence between provision and use (energy consumption).

With increasing distance from the equator, there is a natural mismatch in supply and use on earth: in sunny summer the incoming solar energy is highest, the hot water requirement in private households is the lowest, in winter it is the other way round (main offer time: summer, main use time: winter) . To compensate for this mismatch required the storage of large amounts of heat over long periods (months). This is technically possible without loss using latent heat storage. However, very large storage facilities would be required if one wanted to work to meet requirements and to completely decouple the supply and use of thermal energy. Such systems are currently not economical and are therefore not used.

In addition, in the central and northern latitudes, the short and medium-term changes in solar radiation are very pronounced due to the weather. There are periods of sunshine for days, as well as such days of cloudiness. The operation of solar thermal systems is only efficient when the sun is shining. So while there is no continuous supply of solar energy, the demand for hot water in the periods of weather changes considered can be regarded as largely continuous. There is also a mismatch in supply and demand at this time level, which is why buffer stores are required to bridge bad weather periods.

For cost reasons, in practice small storage systems are used that can store two to three days of storage and collectors with an area that can cover the operator's needs for one to two days in the sunshine months. The mismatch shown due to weather and season always leads to phases of undersupply and oversupply. The former is countered by cost-effective additional heating, the latter by switching off the system at a certain storage temperature (between 50 ⁰ C and 70 ⁰ C in order to prevent calcification of the storage tanks or even to prevent the water from boiling. The collector then becomes very hot when the sun is shining continuously hot, the pressure in the pipe system rises. If the temperature is high enough, the brine (the heat transfer fluid of the solar system) evaporates, the steam escapes through a pressure relief valve or, if this is not available, through screw connections, that cannot withstand the pressure. If the brine loss is sufficiently high, the system no longer works; brine has to be bought and refilled at relatively high cost, which has a major impact on the economic efficiency of the system. The process can be repeated several times a year, right into the low-sun period. The overheating always occurs even in times without hot water withdrawal, namely when the operator is not present for a long time, e.g. B. when you are traveling (summer vacation). Then systems with very small collector areas are also affected.

Overall, small solar thermal systems can currently only be used far below their energetic potential.

In addition, the collectors (electrical and thermal) of small systems are usually rigidly mounted and their orientation to the sun is determined by the respective roof pitch (elevation) and roof orientation to the compass direction (azimuth). Optimal use of solar energy is only given if the solar radiation falls perpendicularly onto the collector surface at all times.

It is considered to be disadvantageous that so far there has been no economically viable technical solution to the problem of the mismatch in the supply of thermal energy from photothermal collector systems and the needs of their users, and that the high efficiency of these systems can therefore not be exploited. Another disadvantage is the repeated loss of brine in the event of overheating of solar thermal systems in summer and the necessary refilling, which results in considerable costs that severely impair the economy of these systems. It is also considered disadvantageous that photovoltaic solar systems have a low efficiency compared to photothermal systems, but the high efficiency of photothermal systems in small systems cannot be used optimally, which is why the installation of solar-electrical systems is currently underway is preferred. With these systems only a very small part of the available solar energy can be used.

The invention has for its object to provide a device for the technical use of solar energy by means of solar collectors, with which an increase in the efficiency of the use of decentralized small systems is achieved. In addition, the risk of damage from overheating should be effectively avoided.

The device according to the invention is defined by claim 1. According to this, the photothermal collector system is oversized with regard to the total of the connected consumers. In addition to the consumers to be supplied, an excess heat exchanger is connected to the associated store, which, in the event of an excess supply of solar energy that exceeds consumer demand, dissipates the excess heat.

The invention is based on the assumption that the photothermal collector and the storage device are dimensioned at school, taking into account the maximum heat requirement of all consumers and the maximum permissible temperature of the heat transfer medium. The invention deviates from this rule in that it provides for an oversizing of the photothermal collector system and possibly also of the memory.

The solar collector system according to the invention is designed in such a way that it covers as far as possible the needs of the operator / user in the low-sun seasons (autumn, winter, spring). For this purpose, the collector areas are dimensioned correspondingly large using calculation methods. A technically known hot water tank is used to store the thermal energy. In order to compensate for weather-related fluctuations in solar radiation (over a few days), this storage tank is dimensioned more generously than before (e.g. 2000 I water or more for a household with 3 - 4 people). In order to avoid overheating and possible damage to the system in the sunny season (summer), according to the invention, an excess heat exchanger is provided at a suitable point in the system, which has the task of dissipating excess thermal energy either only harmlessly or even usefully if necessary. In a preferred, useful embodiment, this excess heat exchanger is designed as a radiator in a suitable room in the house, that is to say in a room whose heating is also desirable in summer. Basement rooms (in which no food is stored) are generally suitable, e.g. B. laundry rooms and rooms for drying clothes, or hobby rooms / workshops. Especially in summer, laundry dries slowly in the basement, which is why electric tumble dryers that require a lot of energy are often used. If, on the other hand, the rooms are heated by solar thermal, the laundry dries quickly and without the additional use of electrical heating energy. Furthermore, the drying room itself remains dry. In addition, it is generally useful to heat cellar rooms in summer, because they become slightly damp when not heated (cellar walls and floor are cool, the outside air has a higher humidity due to the higher temperature - if outside air enters the cellar, the air humidity condenses on the floor and walls. As a consequence, the basement becomes and remains damp and musty.)

According to the invention, the system is provided with corresponding heat exchanger circuits, control circuits and actuators, which make it possible for the further solar heat to be automatically conducted into the excess heat exchanger when the predetermined water temperature in the storage tank is reached.

The boiler of the conventional heating system that is usually available is also included in this heat exchanger circuit. This ensures that the temperature in the boiler remains above the dew point for protection against corrosion, which is otherwise a regular, short firing of the boiler (also in the Summer). It is also planned to conduct the excess heat into the conventional heating circuit of the living rooms (e.g. underfloor heating or radiator system), for which the corresponding pipes, control circuits and actuators are also available. This makes it possible, for. B. in the transitional period and in the winter to supply solar excess heat. This enables an even more efficient use of solar heat. The control system ensures, in a technically known manner, that the desired temperature in the water reservoir (typically typically 50 ^° C.) is not exceeded and not fallen below. The invention thus creates an integrated dual supply system for heating and industrial water in residential buildings, which minimizes the use of other energy sources through optimal use of photothermal solar energy. In order to achieve the greatest possible benefit in the low-sun season, large collector areas are created by covering the entire suitable roof area with photothermal solar collectors. The invention is particularly suitable for all-season heating for "minimal energy houses" with heat recovery. In the low-sun season (heating season), the excess heat is useful for heating the living rooms of the house. A heating of basement rooms is not necessary at this time, since the temperature and humidity conditions prevent becoming damp in winter.

A heat exchanger can also be installed in the soil of the house as excess heat exchanger. With this last solution, the excess thermal energy would be dissipated harmlessly, but also without direct benefit. The indirect benefit is that overheating of the system and loss of brine is avoided.

The above-mentioned methods for avoiding overheating and loss of brine are particularly suitable for retrofitting existing systems. Regardless of this first aspect, the invention relates to the second aspect explained below.

According to the second aspect, a device for the technical use of solar energy is provided, which contains both photothermal collectors for heating a heat transfer fluid and photovoltaic collectors for generating electrical energy. The photothermal and the photovoltaic collectors are each coupled on a defined common receiving surface in such a way that one type of collector is exposed to solar radiation to the extent that the other type is shadowed. The collectors are arranged in collector fields with which large reception areas can be realized, for example as roofing of houses. The receiving surfaces or fields can be constructed from stacked collector levels. The lower level consists of an array of photothermal collectors. The top level contains photoelectric collectors.

According to a possible embodiment, the upper collector level is designed in the form of a lamella field, comparable to the structure and function of sun protection blinds. The lamella fields can be pivoted like blinds and their surface exposed more or less to the sun and at the same time let less or more sunlight through onto the photothermal collector arrangement underneath. The slats themselves are designed in the form of photoelectric collector elements. A preferably motor-driven setting of the slats allows the solar radiation to be divided continuously between both collector levels and types. When the slats are completely closed, all of the radiation falls on them with their photoelectric collector elements on top and it is only converted into electrical energy. When the slats are set up in the direction of the sun, all light falls on the photothermal collector below and is converted into thermal energy (in the day it hits this position also sky light on the photoelectric collector, and is converted into small amounts of electrical energy). It is envisaged that the slats in their respective positions will continuously track the movement of the sun, so that the slats are either always perpendicular to the sun or in the direction of the sun with respect to one direction.

Alternatively, it is provided that the lamellae, which contain the solar-electric collector cells on the top, reflect on the underside and design their adjustment device so that not only the alignment of the top to the sun is possible, but also the continuous adjustment in such a way that the reflective bottom directs the solar radiation onto the thermal collector module below. This also makes it possible to achieve perpendicular radiation incidence with respect to one direction.

In order to achieve a vertical incidence of radiation in both directions (azimuth and elevation), two options are provided:

1. The entire arrangement described above is mounted on a movable support structure, which continuously enables an optimal alignment to the sun of both types of collector perpendicular to the movement of the slats by means of motor control.

2. The slats are divided so that a checkerboard-like structure is created, the fields of which can be pivoted synchronously in two mutually perpendicular directions.

To protect the adjustment devices of the slats in particular, parts or the entire collector device can be accommodated in suitable housings - in the case of the entire system, the housing has the necessary radiation-permeable windows made of glass or suitable plastic. In another possible embodiment, a collector arrangement is again created in two levels. Photoelectric collectors are both movable and fixed, while the photothermal are permanently installed. For this purpose, collector modules of manageable size are created, each consisting of one photothermal and two photovoltaic collector units, which have the same shape and area. The photothermal unit and one of the photovoltaic units are mounted on a common mounting frame next to each other on the lower level. The second photovoltaic unit is mounted on the mounting frame of the module with a corresponding device in such a way that it is displaceable or pivotable and alternatively positioned in the second plane at a short distance directly above the first photovoltaic unit, or directly above the photothermal unit and by means of a locking mechanism can be determined in such a way that it covers this (first photovoltaic unit or the photothermal unit) exactly and shields it from the sun. It is therefore possible to either expose only the two photovoltaic units to the sun, or only one photovoltaic and the photothermal. A stepless shift also enables a variable distribution of solar radiation, but only between the two extremes of 50% to 100% radiation on the photoelectric collector, while at the same time 50% to 0% on the photothermal.

In a further embodiment, a modular collector segment works photothermally on one side and photovoltaically on the other side. An appropriate swivel mechanism turns the desired side towards the sun, the other side is then in the shade. For this purpose, the collectors are mounted on appropriate brackets and provided with flexible supply lines (flexible power lines for the photoelectric or flexible hydraulic hoses for the photothermal ones). Such an arrangement is preferably constructed in a lamella form, similar to that shown above. A preferred collector arrangement is the thermally / electrically combined with rigid thermal collectors in the lower level and adjustable electrical in the level above, in the form of the slats described. To further increase the efficiency of the entire system, but above all the solar thermal part, four possible assembly and operating modes are provided:

1. The collector modules are mounted on swiveling and rotatable brackets, which continuously ensure optimal alignment of the modules to the sun in elevation and azimuth via preferably electric motors and controlled by the control computer.

2. The slats that contain the solar-electric collector cells on the top are mirrored on the bottom. On the one hand, its setting device allows the top surface to be optimally aligned with the sun, and on the other hand, it can also be continuously adjusted in such a way that the reflective underside directs the solar radiation onto the thermal collector module located below. This optimization is only possible in one direction, depending on the orientation of the slats either in azimuth or in elevation.

3. Taking into account all influencing parameters and, if applicable, their temporal course of the year, such as location, supply (radiant power), demand, collector efficiency, possibility of adjusting the orientation of the solar-electric slats, heating costs, feed-in tariff for electricity, etc., a yield for an entire year or cost-optimal orientation of the solar thermal modules in azimuth and elevation determined and assembled accordingly. 4. The checkerboard-like structure is used, with top-side solar-electric collectors that are mirrored on the underside and solar-thermal collectors that are rigidly underneath.

In order to optimize the efficiency of the use of a solar energy generation device, methods and devices for controlling collector systems are described below, which carry out the distribution of solar energy to the two types of collectors and, if necessary, the dissipation of the excess heat as a function of demand and supply. The central unit of the device is an electronic acquisition and control computer (hereinafter referred to as "control computer") with memory and input interfaces for automated and / or interactive input of data, which also includes an Internet connection, and output interfaces for outputting control commands to the solar collector and hot water system , as well as messages to a display device (user console).

The memory is used to provide supply and consumption-related data, e.g. B. the time, a calendar (with regional peculiarities such as public holidays), location-relevant climate and weather data (sunshine duration, seasonal temperature profiles, etc.) and the plant history (records of actual supply and consumption and the location weather and all other parameters since the existence of the respective Investment).

Input data are e.g. B. Information about the water supply (quantity, temperature, current withdrawal quantities), the need (individual consumption), the supply of solar energy (current weather, weather forecast) _/ which are automatically queried and entered online via the Internet connection, as well as further data (current changes consumption-relevant variables such as the number of users, vacation, etc.) - Output data are e.g. B. Control signals for aligning the collectors, or opening / closing valves and switching pumps on and off, as well as information for the plant operator. All time-dependent input and output data are saved in an archive as a function of time (date and time).

The task of the method is to control the thermal energy system in such a way that the available solar energy is primarily converted into thermal energy (amount of heat) at all times and only into electrical energy if the demand for thermal energy is covered for a reasonably manageable, preceding period .

In addition to the amount of heat, the actual water temperature is also included as a parameter for controlling the system. Different minimum temperatures are required for the different uses of the warm water (heating, shower, bath) in order to achieve the desired effect on the one hand and a pleasant condition on the other (lukewarm bath water is usually undesirable).

The thermal energy system is provided with a measuring system which enables various of its state variables to be determined. Temperatures are measured at several points in the system and flow rates in the hot water system and heating circuit, as well as the solar radiation (radiation power) on the collector system, the outside temperature, the relative humidity, and the wind speed and direction.

The temperature measurement in the water reservoir takes place at several points in such a way that the course of the thermal stratification of the water is recorded and a calculation of the amount of heat contained, including the known amount of water, is possible at any time. When withdrawn, the amount and temperature of the leaving the storage Water measured, as well as the temperature of the trailing. The respective changes in the stored heat quantity are determined from this data and the current stock and the current extraction temperature are determined. Measurements in the stock and the withdrawal are continuously updated. Taking into account the current, short, medium, and historical consumption values, it is determined from this how long the supply allows the withdrawal at a certain temperature level. All measurement data are saved in the archive memory of the control computer as a function of time (date and time).

It is envisaged to use a storage cascade in the form of several water containers of small volume of a few 100 liters of water connected in series. These are successively heated (loaded) and used (unloaded). This means that the temperatures in the individual containers are different, and the cooler can be loaded when the sun is less, and the warmer when the sun is strong.

The invention further relates to a method for distributing the energy of an energy supply system to the three types of energy use: heating, hot water and electricity generation.

The task of the process is to distribute the supply of solar energy to the three types of demand with optimal efficiency, with the need for hot water having the highest priority and the need for space heating the second priority. Electricity generation has no priority at all because it is a pure excess introduction into the power grid.

The method according to the invention is characterized by claim 11. It provides that based on a prediction of the temporal availability of the amount of solar energy including weather data and a prediction of the use of each of the three types of energy use based on empirical values The energy offered is divided into use, storage or conversion into another type of energy in such a way that the degree of utilization of the energy utilization system is maximized.

Further refinements of the method are contained in claims 12-24 and result from the following method description.

Exemplary embodiments of the invention are explained in more detail below with reference to the drawings.

Show it:

1 is a block diagram of a photothermal solar energy system with optimizable efficiency of use,

2 shows a schematic representation of a device for combined and coupled photothermal and photovoltaic solar radiation collection,

3 shows a schematic representation of a dual collector system with pivotable solar collector slats,

4 a chessboard-like coliector arrangement, in which the collectors can be tracked biaxially about a height axis and an azimuth axis of the position of the sun,

5 shows an embodiment with superimposed collectors, which are arranged in different planes and are displaceable relative to one another, 6 shows a dual collector with collectors of different types on opposite surfaces, and

Fig. 7 is a diagram of the control computer in which the invention

Procedure is implemented, including the associated peripheral devices.

1 shows a photothermal solar energy system with the possibility of using or dissipating excess heat consisting of a control device 1, for example in the form of a control computer, an input and output device 11 coupled to the control device, for example in the form of a computer keyboard and a display screen ( Display), from a thermal solar collector field 2, which is represented here by a collector module, a storage vessel 3, a conventional boiler 4, a heat consumer as a heat exchanger 5 in the form of a conventional radiator, an excess heat exchanger 9 in the form of a radiator installed in the basement of the building, and a hot water tap 7. At the solar collector field 2 there is a temperature sensor, not shown, for measuring the brine temperature. It is connected to control unit 1 via a measuring line. The storage vessel 3 contains within its outer envelope a smaller inner vessel 31 which is coupled to the drinking water system via an inlet and has an outlet to the tap 33. Process water is located between the outer casing of the dispensing vessel 3 and the inner vessel 31. The storage vessel 3 forms by means of outward and return runs to the boiler 4 and to the heat exchangers 5 and 9 three circuits through which the process water, driven by the pumps 41, 51, 61, can circulate. Three valves 42, 52, 62 support the pumps 41, 52, 62 in interrupting the circuits. Pumps 41, 51, 61 and valves 42, 52, 62 are switched electrically by control unit 1 and are connected to it via control lines for this purpose. In the service water area of the storage tank 3 there is a temperature sensor, not shown, which is connected to control unit 1 via a measuring line. In the process water area of the storage tank 3 there is also the heat exchanger 22 of the thermal solar collector system, to the collector field 2 of which it is connected via a supply and a return line for the brine. A pump 23, which maintains the brine circuit between collector 2 and heat exchanger 22, is preferably located in the return line. The pump 23, like the other pumps 41, 51, 61 and valves 42, 52, 62, is switched electrically by the control device 1 and is connected to it via a control line for this purpose.

The temperature sensor in the storage vessel 3 measures the hot water temperature, which is then recorded by the control unit 1. If it exceeds a predetermined temperature threshold, the control unit 1 switches on either valve 51 or valve 61 and pump 52 or pump 62, depending on the user, and thus directs the hot service water through the heat exchangers 5 or 9. The user accepts the default by appropriate Input on the input and output device 11, where it can also enter the temperature threshold. This is expediently chosen in an area in which there is no lime precipitation from the water. If the measurement of the temperature sensor shows that the temperature in the storage vessel 3 has dropped below the predetermined temperature threshold, the control unit 1 switches the valves 51 or 61 on again and the pumps 52 or 62 switch off again. The upper limit of the temperature range is also limited. At an upper limit, the circuit is opened by the excess heat exchanger 9 so that excess heat is dissipated through it.

Fig. 2 shows a device for combined and coupled photothermal and photovoltaic solar radiation collection. It is largely identical to the device shown in FIG. 1. Instead of the solar thermal collector field, however, it contains a field of combined solar thermal / solar electric collectors, of which three modules 6 are shown. Each module is connected to the control computer 1 via a measuring line (for temperature measurement) and a control line. It also contains a measuring sensor 21 for measuring the solar radiation (radiation power). Furthermore, the system has an inverter 7. This is connected to the solar-electric units of the collector modules 6 via an electrical collecting line and has an electrical connection 71 to the public power grid. The collector modules are constructed in two levels, the lower level containing the rigid solar-thermal collector unit 61, the upper level the adjustable solar-electric, here in the form of adjustable slats 62. The slats are adjusted by means of electric motors or similar actuators, which are not described here are shown. These actuators are operated by the control computer 1 via control lines. The three collector modules shown show three different settings, which are brought about by the different position of the solar-electric collector fins 62. The slats 62 are set up in the left module, so that they themselves do not receive direct sunlight. The sunlight falls entirely on the solar thermal level of the collector units 61. In the right module, the slats 62 are completely closed, the sunlight falls entirely on them, and the solar thermal level of the collector units 61 does not receive any sunlight. In the middle module, the slats are inclined so that half of the sunlight falls on both levels.

The pipe connections of the individual collector modules are not shown in more detail in FIG. 2. They are designed and equipped with the necessary valves (operated by the control computer) so that each module can be individually inserted or excluded in the brine circuit as required. Alternatively, this option can be dispensed with, which reduces efficiency, since brine will always flow through all collectors, even if not all of the sunlight falls on it. Thereby, heat energy in the sunless collectors is lost to the environment. 3 schematically shows a collector arrangement with a photothermal collector 65 and numerous photovoltaic collectors 66 arranged above it, which are designed in the form of lamellas and can be pivoted about an axis 67 in each case. The photovoltaic collectors 66 form a lamella field and they can be pivoted together in the manner of a venetian blind in order to either cover the photothermal collector 65 and thereby shade it from the sun, or to expose it to the incident solar radiation. The photothermal and the photovoltaic collectors are thus coupled in such a way that one type is exposed to solar radiation to the extent that the other type is shadowed. The photothermal collector 65, which forms the carrier here, can be pivoted in a motor-controlled manner about a horizontal axis 68 in order to change the elevation angle of the entire collector arrangement in accordance with the position of the sun. The vertical axis 69, which carries the collector arrangement, can be pivoted in the direction of the arrow 70 in order to adjust the azimuth angle in accordance with the position of the sun.

It is possible to mirror the slats on their underside and to design their adjustment device so that not only the alignment of the top to the sun is possible, but also the continuous tracking of the reflecting underside so that it always sends the solar radiation onto the photothermal collector 65 steers.

In the embodiment of FIG. 4, the lamellas that form the photovoltaic collectors 66 are subdivided, so that a checkerboard-like structure results. Each field 80 can be pivoted individually about a horizontal height axis 81, which corresponds to the axis 67 of FIG. 3, and about an azimuth axis 82 running perpendicularly thereto for tracking in accordance with the azimuth angle of the sun. 5, a photothermal collector 85 is arranged in a common plane with a first photovoltaic collector 86. A second photovoltaic collector 87 is located in a plane above the two collectors 85, 86 and can be moved in this plane. All three collectors have the same shape and size. When the collector 87 is above the collector 86, the collectors 85 and 87 are illuminated by the sun while the collector 86 is shielded. In this way, half of the solar radiation is absorbed by the photothermal collector 85 and the other half by the photovoltaic collector 87. When the upper collector 87 is pushed over the photothermal collector 85, all the solar radiation that falls on the surface in question is converted into electrical energy. The proportion of the thermal energy obtained in the total energy can be changed continuously by intermediate positions of the upper collector 87.

In this embodiment variant, too, the underside of the upper collector 87 can be mirrored.

FIG. 6 shows a collector module in which a photothermal collector 90 is combined with a photovoltaic collector 91 to form a plate structure which can be pivoted about a horizontal axis 92 in order to expose one or the other collector to solar radiation. The collector 90 is connected to a hose system via flexible hoses, not shown, and the collector 91 is connected to a line network via flexible electrical lines.

In the following, the procedure for controlling a hybrid energy supply system with solar energy generation according to requirements and supply is described. The control according to the invention generally has the task of optimizing the “efficiency of use” η _N. The efficiency of use is the ratio of the energy E _N TO used in a certain period of time to an energy E _A not necessarily offered in the same period (in contrast to this, the known "degree of utilization" offers and use relates to the same period): with the optimization task: max (η _N ) (2)

The energy E _{A offered} is in the form of solar radiation energy E _s :

E _A = E ₅ (3)

It is used partly as thermal energy E _τ for hot water E _τw and heating E _TH in-house, partly as electrical energy E _{E /} which is fed into the public grid.

In particular, the object _{according to the invention is} to convert, store and / or use the amount of solar energy E _sta t (t) = E _Atat (t) actually offered at any point in time in such a way that, in particular, that it is used later Actual use of thermal energy E _T t _a t (in the form of hot water E _TW tat and heating water E _T Htat) / but also the actual use of thermal E _τtat and also electrical energy E _budget that may occur at the same time as the offer Requirement (2) met. The following special features must be taken into account in detail: o The amount of solar energy E _{5 offered} is subject to strong temporal fluctuations and is also strictly correlated with the position of the sun. o The use of the two _{types of} thermal energy E _τw and E _TH is predominantly neither correlated with one another nor with the supply in terms of time and quantity and fluctuates greatly over time. The use of warm water is almost always offset in time (by hours and days), that of heating energy often (usually by hours). o The use of electrical energy E _E is temporally correlated with the supply, but dependent on the demand (of the use) of thermal energy and subordinate to it.

_{According to the} invention, predictions about the energy offered E _{AVO angebot} and the energy used E _Nvor are made in advance over a period of time Δt of several days and by means of these predictions the _degree of utilization for this period of time Δt is optimized according to (2). The optimization according to the invention consists in that at each point in time of the prediction, the energy JE _Ata t then actually offered is converted into the three possible use energies E _τw , E _TH and E _E in a measure and ratio that the demand (predicted use) for thermal Energy E-rvor, primarily to E _TWv or and secondary to E _THV OΓ, is covered as far as possible over the period Δt (taking into account the storage capacity of the thermal energy system) and converted into electrical energy E _E only if a further conversion into thermal energy E _{TW /} and / or E _TH would require this energy for the period Δt (taking into account the energy supply E _A to be expected in the entire period Δt before), or else would exceed the storage capacity (overheating). How shown, the conversion into electrical energy E _{E is} completely independent of the needs of the operator (feed into the power grid). The optimization therefore does not need to take its needs into account, which is why no prediction is made about it. However, knowledge of temporal current demand peaks in the network is taken into account (the invention therefore preferably converts to electrical energy at lunchtime because a lot of electricity is required) when primary and secondary optimization requirements (also taking into account the offer and use of periods of the prediction phase Δt) lying further in the future allow this.

According to the invention, the predictions are supplemented by monitoring predicted parameters, such as, for. B. solar radiation, derived from the actual supply of solar energy E _Atat = E _{stat /} the amount of heat in the storage, supplied to it, as well as the amount of heat used, as well as converted solar energy, derived from it the actually used energy, separated by types of use. This compares the prediction against the actual state. This is used to check the functional state of the system and to further optimize operation by making corrections if the actual state deviates from the prediction.

According to the invention, the optimization is carried out by means of predictions about the energy supply and use and the checking thereof and the control of the system derived therefrom.

Technically known methods and devices are used for the prediction, such as the Bayes' theorem, the Dempster-Shafer theory, the maximum likelihood method or artificial neural networks KNN.

The check (determination of the actual state) is based on measurements of the relevant parameters. The technical conversion of the actually offered solar energy E _stat into the three types of use at any time of the actual offer takes place on the basis of the predictions of the offer and use by means of corresponding actuation and adjustment of the collector control

(solar-electric / solar-thermal) and the associated valves, pumps and switches in a technically known manner by the control computer of the system. As a result, the converted energy is stored in each case for hot water and / or heating energy for later use, or for direct heating, or in the form of electrical energy directly to the public power grid. The actual offer and the actual use are taken into account.

When the energy supply system is started up for the first time, estimated consumption values are assumed. Starting with commissioning, all consumption processes are recorded and quantified by measurements, which document the actual consumption habits and their changes. All recorded data are saved in the archive memory of the control computer as a function of time (date and time).

When estimating the expected short and medium-term (a few days to a week) consumption, current and weather forecast data are also taken into account in addition to the measurement data mentioned and converted into consumption-relevant influencing variables, taking into account the current and historical consumption habits. This is because demand and supply are not independent of one another; For example, on very hot summer days, showering is often carried out at a lower water temperature and shorter than in cold winter, where bathing is also more frequent and with larger amounts of water. Wind and very low outside temperatures require more heating energy in winter than mild temperatures and no wind. The need, including relevant data from the archive memory of the control computer, is estimated using known methods, preferably using artificial neural networks (KNN), which will be explained in more detail later. In a preferred mode of operation, the consumption of hot domestic water is given top priority when estimating the demand, then the heating of rooms where this is necessary (living rooms), thirdly the generation of electricity, fourth the heating of cellars or similar and with last priority, and only with purely photothermal old systems, the dissipation of excess heat without direct use. The system enables operations to be controlled with other priorities. All determined consumption data are saved in the archive memory of the control computer as a function of time (date and time).

All supply-relevant data of the past (weather observations) available for the location are recorded for as long as possible from a few years to a few decades before the system is started up and saved in the archive memory of the control computer as a function of time (date and time). Likewise, all available supply-related data has been continuously recorded since the system was commissioned and saved in the archive memory of the control computer as a function of time (date and time).

The current and short-term (one to two days) and medium-term (three to four days, up to one week) expected solar energy supply are determined or estimated and taken into account when controlling the system. Various information is processed in the control computer. On the one hand, these are constant parameters, such as the geographic location coordinates, the orientation of the collector system to the surface of the earth, the characteristic data of the system (collector area, efficiency, storage volume, etc.). Then there are periodically changing parameters with a known temporal course, such as the day and year of the sun, sequence of working days and holidays, etc. Finally, there are changeable parameters, the chronological course of which is only for short periods (a few days) and with finite Accuracy can be predicted, such as the weather expected in the short and medium term. B. from the Forecasts by the German Weather Service or similar facilities that are automatically queried and entered via the Internet connection. This also includes the current solar radiation, which is measured at the collector field. From this data, including the stored archive data, the short and medium-term heat quantities and temperatures to be expected in the storage tank are calculated or estimated. This is done with known technical methods, preferably with artificial neural networks (KNN), which are explained in more detail below. All determined offer data are saved in the archive memory of the control computer as a function of time (date and time).

The parameters of the expected consumption and the expected supply as a function of time, as well as the heat energy supply determined by measurement and its temperature are used in the control computer in a technically known manner in order to optimize the control of the entire system. The goal is to convert as much solar energy into heat energy as possible and only switch to conversion into electrical energy if the supply and demand for thermal energy are the same in the current, short and medium term, or if the demand is not met, the capacity of the Memory is exhausted. The technique of artificial neural networks (KNN) is preferably used. Input data are the parameters mentioned above for determining supply and demand. Output parameters are estimates of the supply and consumption in the short and medium term, from which in turn control signals are derived. Actuate the control signals z. B. valves and pumps of the hot water and heating water system, as well as the motors with angle sensors and other actuators (electrical switches, pumps, valves) of the solar radiation collector devices. The system therefore maintains the temperature and its stratification, as well as the amount of warm drinking water in the storage container for certain selectable periods within certain predetermined limits. If the limits are exceeded, the system carries the excess thermal energy if necessary, directly to the heating system or indirectly via a buffer store provided for heating purposes. If the demand for heating energy is met, or the storage is full, or no heating energy is required, and the hot water demand is saturated or can be provided for the intended period of time, the system switches to the operation of the solar-electric energy collection. As is usual at KNN, the system is continuously trained using the "error backpropagation" method to optimally take into account the specifics of supply and consumption of each individual system.

The process also takes into account the radiation-dependent efficiencies of the collector systems. In situations where the hot water requirement is not covered, but the efficiency of the photoelectric collectors is greater than that of the photothermal ones, the photoelectric ones are used. These provide electrical energy even in low sunlight, while z. B. the temperature increase in the thermal collector can be uselessly small because it is below the current storage temperature.

According to the invention, the forecast of the energy supply is essentially created via the weather forecast (e.g. German Weather Service), as well as via geographical (location, orientation of the collectors) and temporal data (season, time of day). The forecasts are updated regularly and dynamically in line with the situation. H. with a stable supply situation (e.g. stable weather conditions) B. updated once a day, in an unstable situation (unstable weather) is updated more often. The check is carried out with the data of the measuring systems belonging to the system.

The usage prediction is derived from their observation, for which purpose individual usage habits of all users are recorded. A regular update is carried out to take account of fluctuations in time (e.g. seasonal) and changes in usage habits consider. The system is trained for this. During the training at the beginning of operation and also in later training phases to update usage behavior, the number and identity of the users are entered into the system. In particular, immediately before the use of large amounts of warm water (for bathing, showering, washing hair), the current users are made known to the system (identification) and the energy usage quantities then determined are assigned to the identity. In this way, a user-related prediction is possible, for which the presence and absence of individual users is made known to the system with identity.

In a preferred embodiment, the control consists of an arrangement which is shown schematically in FIG. The control computer 1, e.g. B. in the form of a PC has the archive memory and also provides the date and time. It is connected to the following subunits via interfaces: the interactive input unit 24, the automatic input / output unit 25, the Internet connection 26, the output unit 27, the display unit 28 and the artificial neural network, KNN 29. The core of the actual control is the artificial neural Network that derives optimal timing and control functions for the systems for energy conversion and storage from the multitude of input parameters to be taken into account (weather forecast, usage forecast, current weather and usage data). The entire system can be integrated into a central home computer. Alternatively, parts can be created decentrally and z. B. communicate via radio (WLAN) or wire with a central computer. The central computer can in this case, for. B. contain the interactive input unit (keyboard).

Via the interactive input unit 24, the user transmits usage-specific data and their changes to the control computer 1. These are, for example, the number and identity of the users present N, (the identity includes gender and date of birth as well as occupational information - working, half-day, full-time or not, students etc. and is used to identify and take into account individual usage habits for hot water and heating energy) as a function of the calendar time t (exact date, over days, months, during the year). B. vacation trips and other absences as well as guests etc. are taken into account. As far as possible, this data is entered in advance, at least several days in advance. However, unforeseen short-term changes are also entered; the property of KNNs is used to deliver similar, like the trained input parameters, also similar to the expected output parameters - they work "intuitively". The usage-specific data are used to predict the use of thermal energy E _Tv or (t) as the sum of the amounts of energy for the preparation of hot water E _T w _VOr (t) and for space heating EτHv _or (t), taking into account temporal peculiarities (season, month, day of the week) ) determined as a function of time t (the basis for this is training that the system is subjected to:

Eτvor (t) = Eτwvor (t) + E _THv or (t) (5)

The data from individual or all sensors and sensors for checking the predictions, which are described above and summarized below, are queried and read in via the automatic input / output unit 25. K (k = element of the set of natural numbers) different water temperatures T _wk (t ) in different layers of the storage tank, flow and return temperature of the brine circulating in the thermal collector system T _Sv (t), T _Sr (t), outside air temperature T _L (t), solar radiation L _SOL (t), also wind speed v _w (t ) and direction φ _w (t), air pressure p (t), current Isoι _. (t) and voltage Uso_ (t) at the output of the photovoltaic solar collectors, etc., each as a function of time t. Furthermore, thermostats are installed in the living rooms to be heated with thermal solar energy, of which the target and actual temperatures T _Rso n (t), T _Rist (t) are given to the control computer 1 via the automatic input / output unit 25 will. The latter also flow into the review of the predicted use described above (also in the training to improve system operation), otherwise the data serve to determine the actual amount of solar energy E _Stat (t) and the actual use of thermal energy Eτta _t (t) for the hot water preparation E _T w _ta t (t) and the heating E _TH ta _t (t) as well as the actually offered excess energy of solar energy E _s (t), which after conversion in the photoelectric collector as an offer of solar electrical energy E _E (t) ins Power grid can be fed, each as a function of time t. The amount of heat Q _w present in the store is calculated from the measured temperatures T _wk (t) and the known storage parameters, such as the amount of water and the position of the temperature sensors. The following applies:

Eτtat (t) = Eτmat (t) + E _T Htat (t) (6)

Estat (t) = E _τtat (t) + E _S p _L ustat (t) = Eτwtat (t) + E _TH tat (t) + E _SPLUS (t) (7) further

When determining E _TW tat (t) and E _TH tat (t), the capacity and losses of the hot water tank as well as losses of the heating energy due to the house insulation are taken into account, the latter taking into account the current weather data and the weather forecast described below (outside temperature, wind, solar Irradiation, etc., from which heat losses through the outer shell of the house can be determined).

The input (transfer / storage and use of the measurement data) takes place in dynamically adapting intervals. The system uses repeated, continuous queries to determine how much each parameter changes. If it remains constant, there is no data transfer. Exceeds the change a predetermined threshold value, the measurement data are adopted. The intervals of the continuous query are adapted to the currently expected rates of change for each specific parameter. If a parameter changes quickly, e.g. If, for example, the solar radiation in cloudy, windy weather, the parameter is queried in short time intervals (minutes or a few seconds) (in this example also the flow and return temperature of the brine), it changes slowly, as is usually the case with air pressure is queried in long time intervals (e.g. in hours). The polling intervals are dynamically adjusted; they are shortened when it is determined that the rate of change increases and lengthens when it changes.

The weather forecast data, e.g. B. the German Weather Service, queried and entered. These are the predicted outside temperature T _Lvor (t), radiation intensity (power) of the sun on the ground or on the collector I _Svo r (t), _{degree of} cloudiness, wind direction / speed φ _Wvor (t), v _Wvor (t). Air pressure p (t) as a function of the time of day. The geographic parameters (location, orientation of the collectors to the sun), as well as the efficiency of the collectors and other required system parameters (storage capacity, heat loss parameters of the building, etc.) are entered into the system at installation. The computer provides the date and time. On the one hand, these data serve to determine the predicted supply of solar energy E _Avor (t) as a function of time t. With the determined values of the expected use E _NvOr (t) of thermal energy (for the preparation of hot water E _TWvor (t) and for space heating E _THvor (t)), the expected surplus, _i.e. the expected supply of surplus, also becomes available energy e _PLU s _vo r (t) as a function of time t determined, especially the geographical and other system parameters are considered:

EsPLUSvor (t) = E _Svor (t) - Eτvor (t) (9) It is the task of the controller to distribute the supply of solar energy to the three types of demand, hot water, heating, and electrical power with optimal efficiency, i.e. to serve the demand for hot water with the highest priority, the second priority is the need for space heating, and lastly the generation of electricity , as a pure excess use, ie the electricity requirement is not used as a control variable.

The following subtasks are part of the optimization:

First of all, the expected values should match the actual ones as precisely as possible, ie the predictions should be as precise as possible, so it must be minimized: min (E _T vor - Er ₀₁ ) (10) min (EjWvor - Eγwtat) (H) min (E _TH before ~ E-rHtat) (12) min (E _Svor - E _sta t) (13)

Equations (10) to (13) are to be fulfilled by the KNN using the measurement and input data. For this purpose, the KNN is trained in a technically known manner, the accuracy of the system being increased by means of repeated training phases during the operating period. If equations (10) to (13) are fulfilled, three different cases are possible, which result in a correspondingly adjusted control:

1.) Estat = E _Tvor (14)

Then the system is controlled in such a way that the expected integral use (demand) of hot water E _T wvor and heating E _THV OΓ follows the current course of time the usage-based, timely division is covered. This means that the residents' time consumption habits are taken into account. For example: If there are people in the house during the day in winter, the heating requirement is already served in the morning, even if the hot water requirement (which is highest in the evening or morning) has not yet been met - as long as it can be expected that it will still be during the day can be covered. If people are in the house only in the evening and at night, as well as in the early morning, the space heating can also be reduced during the day, the demand for hot water can be covered faster and the heating increased in the afternoon.

2.) E _stat > E _Tvor (15)

Then, in the cold season, the procedure is as above, and additional solar surplus energy is converted into electrical energy and fed into the power grid (if possible, at times of peak demand for electricity). In summer, the usually lower demand for hot water / heating is covered in times of low general electricity demand, in times of high electricity demand (around noon) electricity is generated and fed into the grid.

3.) -Stat <E ■ Tvor

Then the demand for hot water is supplied and only if this is covered is the heating required if necessary, otherwise adapted to the needs (see above).

In any case, optimize:

min (a E _stat - E _TWV or) (13) min (b E _stat - E _THv or) (14) min (c Es _t at - E _SPL usvor) (15) where the solutions are a, b and c, with: a + b + c = 1 (16)

In a preferred embodiment, the input variables for the KNN are the predicted and the actual energy parameters as a function of time.

In another preferred embodiment, the input variables for the KNN are the predicted and the actual variables and measurement parameters that are input via the interfaces (interactive input unit, automatic input / output unit, internet connection), i.e. weather data, usage parameters, temperatures in the system, etc.

The system and the control are also designed in such a way that, above all, the demand for primary hot water and heating energy are avoided. A shortage of the hot water requirement is avoided by making small excess quantities available for safety in the hot water tank. This hot water tank also serves as a buffer, from which, if necessary, energy for space heating can be drawn if an excess of hot water is detected. In addition, it is provided to provide storage capacity for space heating, which makes it possible to use energy collected during the hours of sunshine for space heating in the sunless times of the day. Correspondingly large memories are provided for this.

Claims

1. Device for the thermal use of solar energy, with thermal collectors (2) for heating a heat transfer fluid, a memory (3) for storing the heat transfer fluid and for its delivery to at least one consumer circuit, characterized in that the totality of the collectors (2) and / or the store (3) is oversized with regard to the totality of the connected consumers, and that an excess heat exchanger is connected to the store (3) which, in the event of an excess supply of solar energy exceeding the consumer demand, dissipates the excess heat.

2. Device according to claim 1, characterized in that the excess heat exchanger is a radiator contained in a basement.

3. Device according to claim 1, characterized in that the excess heat exchanger is installed in the ground, in thermal contact with it.

4. Device for the technical use of solar energy, with photothermal collectors (61) for heating a heat transfer fluid and photovoltaic collectors (62) for generating electrical energy, the photothermal and photovoltaic collectors each being coupled in such a manner on a defined receiving surface are that one type is exposed to solar radiation to the extent that the other type is shadowed.

5. The device according to claim 4, characterized in that the photothermal collectors are then exposed to the sun by an automatic control when a heat requirement - z. B. by a drop in temperature - is detected.

6. The device according to claim 4 or 5, characterized in that slats with photothermal collectors (61) and slats with photovoltaic collectors (62) are arranged at right angles to each other in two overlapping levels.

7. The device according to claim 6, characterized in that adjustable / pivotable slats with photothermal collectors and adjustable / pivotable slats with photovoltaic collectors are arranged at right angles to each other one above the other.

8. Device according to one of claims 4-7, characterized in that the collectors consist of plates, the position of the sun by pivoting about a height axis (81) and an azimuth axis (82) can be tracked biaxially.

9. Device according to one of claims 4-8, characterized in that the collectors (85, 86, 87) of different types are arranged one above the other and are movable relative to one another.

10. Device according to one of claims 4-9, characterized in that collectors (90, 91) of different types with opposite surfaces are arranged on a common support which around an axis (92) is pivotable to expose one or the other surface to the solar radiation.

11. Method for distributing the energy of an energy supply system containing a solar energy generation plant to the three types of energy use: heating, hot water and electricity generation, characterized in that based on a prediction of the temporal availability of the amount of solar energy, including weather data, and a prediction of the use of the energy use types Based on empirical values, the energy offered is divided into use, storage or conversion into another type of energy in such a way that the degree of utilization of the energy generation system is maximized.

12. The method according to claim 11, characterized in that the prediction of the use takes place over a period of several days.

13. The method according to claim 11 or 12, characterized in that the storage capacity of the system for thermal energy and electrical energy is taken into account in maximizing the degree of utilization.

14. The method according to any one of claims 11-13, characterized in that for the determination of that energy which is used for the generation of electricity, the temporal current requirement of the network into which feed is taken into account.

15. The method according to any one of claims 11 - 14, characterized in that the actual operating state of the energy supply system Correspondence with the availabilities and / or types of energy use assumed on the basis of the prediction is examined and corrections to the prediction are carried out on the basis of ascertained deviations.

16. The method according to any one of claims 11-15, characterized in that the usage types are predicted by learning and correction processes of the user behavior.

17. The method according to claim 16, characterized in that the user behavior is assigned to individual users and that their presence is detected by a detection system.

18. The method according to claim 17, characterized in that the user is assigned a file that contains information about the properties, habits and plans of the user.

19. The method according to any one of claims 11 - 18, characterized in that an artificial neural network (KNN) derives control and actuating functions for the energy conversion and storage from a plurality of input parameters.

20. The method according to any one of claims 11-19, characterized in that temporal peculiarities such as seasons, days of the week, etc. are taken into account in the prediction.

21. The method according to any one of claims 11 - 20, characterized in that data on the actual amount of solar energy captured and the actual use of thermal energy and excess energy that can be fed into the network are determined and stored.

22. The method according to any one of claims 11-21, characterized in that the changes over time of at least one parameter are recorded, the actual value being adopted instead of the prediction when a threshold value is exceeded.

23. The method according to any one of claims 11-22, characterized in that weather data are queried via an Internet connection.

24. The method according to any one of claims 11-23, characterized in that the expected supply of excess energy is determined as a function of time on the basis of the prediction of the supply of solar energy and the prediction of the use of thermal energy.