WO2012172159A1

WO2012172159A1 - Solar power plant

Info

Publication number: WO2012172159A1
Application number: PCT/FI2012/000031
Authority: WO
Inventors: Reijo Hautalahti
Original assignee: Reijo Hautalahti
Priority date: 2011-06-13
Filing date: 2012-06-12
Publication date: 2012-12-20
Also published as: FI124118B; FI20110199A; IN2014DN00237A; FI20110199L; FI20110199A0

Abstract

Solar power plant generating electricity and heat comprising an element generating electricity (1,6), a heated element (4) and a cooling element (8). The element generating electricity (1,6) comprises thermoelectric elements and possibly also solar cells. The heated element (4) and the cooling element (8) can be liquid media that have been arranged to absorb solar energy. The element generating electricity (1,6), the heated element (4) and the cooling element are laid one on the other in layers, and the layers are laid one on the other in planar or cylindrical arrangement. The power plant may also comprise at least one reflector (9) that is arranged to enhance the intensity of solar radiation.

Description

Solar Power Plant

The present invention relates to a combined electricity and heat solar power plant. In order to prevent human-induced climate change, it is necessary to significantly increase such energy production which does not induce carbon dioxide emissions. One of the most promising forms of carbon dioxide-free energy production is solar energy. Solar radiation energy has been exploited in numerous ways both in direct heat generation and in electric power generation using solar cells.

Also, thermoelectric elements have been used to convert solar energy to electricity, and in combination with them, also thermal technology applications have been implemented. Publications CN 1928358, JP 57069786, JP59097457, and DE 102008008652 present such systems but each of them has a structure which is either, complex, inefficient, or eligible only in specific applications. The present invention offers a simple, efficient, and versatile solution for combined electricity and heat generation utilising thermoelectric elements.

More precisely, the present invention is characterized by what is disclosed in the characterization part of the independent claims 1, 7, and 9.

Figure 1 shows the cross-section of the first and the second embodiment. Figure 2 shows the structural principle of a ceramic body thermoelectric generator. Figure 3 shows the structural principle of a thermoelectric generator without a ceramic body. Figure 4 shows the operating principle of a dye-sensitized solar cell.

Figure 5 shows an energy generator system which includes the first or the second embodiment of the present invention.

Figure 6 shows the cross-section of the third embodiment. Figure 7 shows an energy generator system which includes the third embodiment of the present invention.

Figure 8 shows the cross-section of the fourth and the fifth embodiment.

Figure 9 shows an energy generator system which comprises the fourth or the fifth embodiment of the present invention.

Figure 10 shows the cross-section of the sixth embodiment.

Figure 11 shows an energy generator system which comprises the sixth embodiment of the present invention.

The structure of the first embodiment of the invention is a cylindrical construction whose shape and dimensions are chosen according to the use of the application and the requirements of the operating environment. Figure 1 shows the cross-section of an apparatus according to the invention. Vacuum tube techniques commonly used in solar collectors can be used with this embodiment. Surface 1 comprises a solar cell which can be for example a dye-sensitized solar cell or a window-glass solar cell. Below the solar cell there is a vacuum 2. The third layer is a thin plate covered with black material which intensifies the absorption of the solar energy into the plate. Plate 3 can be for example copper or other thermally well conductive material. The surface of the plate 3 can be a microstructure which improves thermal conductivity. The fourth layer is a heated element, which in this case is a heated medium 4. Fifth in the structure, there is a thin plate covered with black material which intensifies the absorption of the solar energy into the plate. The plate 5 can be for example copper or other thermally well conductive material. The surface of the plate 5 can be a microstructure which improves thermal conductivity. The sixth layer is a thermoelectric component 6. Two different compositions of a thermoelectric component are presented in figures 4 and 5. The seventh layer inwards the embodiment is a core 7. The surface of the core can be a microstructure which improves thermal conductivity. Inmost in the apparatus is a cooling element, which in this case is a cooling medium 8. Solar radiation intensity incident on the apparatus can be intensified with mirrors 9. Solar radiation intensity can be intensified also with lenses either together with mirrors or separately. There may be a number of mirrors and lenses, and they can be directed towards the Sun passively or actively. The construction and the amount of mirrors and lenses are chosen according to the price and the intended energy density. Mirror and lens constructions necessary for the applications are not described here in more detail as a person skilled in the art can implement them based on professional literature.

Solar cell 1 receives solar energy as direct and scattered radiation and possibly also reflected in a mirror. Incident solar energy penetrates through the solar cell 1 which forms the surface layer, and part of the solar energy is transformed into electrical energy. Below the solar cell I, there is a vacuum, the purpose of which is to reduce conductive thermal losses. Solar energy transfers from the solar cell 1 through the vacuum 2 and is absorbed by the black surface of the plate 3. The solar energy is then conducted through the plate 3 to the heated medium 4. The medium is a liquid chosen according to the operating environment and the requirements set by the structure of the embodiment. As an example, different ethylene compounds, glycol, mineral oils and water can function as the medium Water is a good medium due to its good heat transfer capacity in working environments where there is no fear of freezing up and also where water does not boil. When water boils, heat transfer in the system is disturbed. Increasing the water pressure increases the boiling temperature, but high water pressure poses a danger. Therefore, if the water pressure is increased, necessary changes to the construction of the apparatus must be implemented simultaneously, and safety appliances that comply with requirements must be installed to the apparatus and its actuators. Thermal energy is then conducted through the plate 5 into the thermoelectric element 6 and gives rise to temperature T_h in the thermoelectric element. The operating principles of two different thermoelectric elements 6 are presented in more detail in figures 2 and 3. Thermal energy conducted through the thermoelectric element is then conducted to the core 7 and through it into the cooling medium 8. Now, lower temperature T₀ is formed on this side of the thermoelectric element, and a temperature difference is formed across the thermoelectric element between the cool side and the warm side. The cooling medium 8 can be water, which has a good heat transfer capacity. The operating environment must be such that there is no danger of freezing up. In colder environments, glycol, ethanol, or other suitable liquid is chosen based on price and/or other essential properties. Figure 4 shows the operating principle of a dye-sensitized solar cell. Solar radiation is directed to an active electrode 103 either from the direction of a conductive body 101 or from the direction of a counter electrode 102. In figure 4, the solar radiation is exemplarily shown to come from the direction of the body 101. The active electrode 103 consists of a network of nanoparticles whose pores get filled with an electrolyte 104. The nanoparticles 105 are semi-conductive material, and there are dye molecules 106 attached on their surface. The semi-conductive material used is typically titanium dioxide Ti0₂. The electron structure of Ti0₂ is such that the nanoparticle network it forms does not absorb visible light. The materials research of dye-sensitized solar cells is in fast development phase both in basic research and in applications research, so in the future, a person skilled in the art evidently chooses the best of the solar cell materials to be developed taking into consideration the operating environment, performance, price, and other boundary conditions set by the application. The absorption of light in the cell happens in dye molecules 106 attached on the surface of the particles 105. Due to the absorption of light, electrons are transferred from dye molecules 106 to semiconductor 105. Semiconductor particles form a network, through which the electrons move to the conductive body 101 and pass further through an external circuit to the counter electrode 102. At the counter electrode 102, the electrons move to the ions of the electrolyte 104 that then pass to the active electrode 103 and restore its initial state. In the first and the second embodiment of the present invention, the dye solar cell is chosen such that the solar energy is sufficient for the primary heat source of the heated media in order to create a sufficiently large temperature difference T_h - T_c between the warm side and the cool side of the thermoelectric element. The remaining solar energy generates electrical energy in the dye-sensitized solar cell. In the third and the sixth embodiments of the present invention, a high-efficiency solar cell is chosen, in which case the solar cell produces electrical energy efficiently.

Term window-glass solar cell is used to denote a solar cell which lets visible wavelengths of the electromagnetic spectrum pass through.

The solar cell can be installed between two glass plates or immersed in plastic. The glass sheet can be selective. Plastic can be flexible, which enables shaping the plastic as desired. A person skilled in the art can naturally utilize up-to-date professional literature when choosing the materials, structure, and circuits of the solar cells. There are numerous n-type thermoelectric compounds used in thermoelectric elements 6, such as, for example, bismuth-tellurium Bi₂Te₃, lead-tellurium PbTe, silicon-germanium SiGe, and silicon/silicon-carbon composite Si/SiC. Si/SiC material is used in quantum well semiconductors. Respectively, useful p-type thermoelectric compounds are, for example, bismuth-tellurium Bi₂Te₃, antimony-tellurium Sb₂Te₃, lead-tellurium PbTe, tellurium-antimony- germanium-silver TAGS, and silicon-germanium SiGe, and composite of boron-carbon compounds B₄C/B₉C, which is used in quantum well structures.

Figure 2 shows the structural principle of a ceramic body thermoelectric generator which uses a ceramic support structure 41. Fh is used to indicate the flow of the heated medium 4, F_c the flow of the cold medium, and F_q the thermal flow. The flow F_h of the heated medium transfers the thermal energy of the medium by convection into plate 5. Between the plate 5 and the ceramic supporting structure 41, there is material 42 which decreases the thermal resistance of the contact. Consequently, heat is conducted through the layer 42 into the ceramic supporting structure 41 and through it onward through the material 42, which decreases the thermal resistance of the contact, into the metal plate 43. Heat is then conducted further through the metal plate 43 to the n-type semiconductors 44 and p-type semiconductors 45. On the opposite side of the semiconductors, heat flows respectively through similar layers in the opposite order. The purpose of the insulation 46 is to decrease heat losses so that maximum heat flow is directed through the thermoelectric element 6. If boundary conditions set by the application allow so, the ceramic supporting structure can be left out, and the construction of the thermoelectric element is then as depicted in figure 3, but then material 42 must also have sufficient electrical insulation capability. Metal plate 43 connects the n-type thermoelectric semiconductors 44 and p-type thermoelectric semiconductors 45 together. This is how to form thermoelectric generators that can be connected together in series and parallel to form modules. The modules can then be connected in series and parallel to reach desired values for current and voltage. The operation of n-type thermoelectric semiconductors 44 and p-type thermoelectric semiconductors 45 is based on thermal diffusion of electrons e^" and holes h⁺. Charge concentration increases in both types of thermoelectric semiconductors towards the cold side, and thus, there will be electric field E of similar size but opposite direction in both n-type and p- type semiconductors, respectively. In other words, opposing electrical potentials are formed between the cold side and the hot side in n-type and in p-type semiconductors.

Thermoelectric semiconductors have different optimum operating temperatures which allows for a rough classification of thermoelectric semiconductors in three groups: low-temperature thermoelectric semiconductors, mid-temperature thermoelectric semiconductors, and high- temperature thermoelectric semiconductors. Examples of low-temperature semiconductors are Bi₂Te₃ and Sb₂Te₃, whose optimum operating temperatures settle around 100 °C. PbTe and TAGS are examples of mid-temperature thermoelectric semiconductors, whose optimum operating temperature is around 400 °C. SiGe, Si/SiC and B₄C/B₉C are examples of high- temperature thermoelectric semiconductors, whose optimum operating temperature is around 800 °C.

Modern efficient research of thermoelectric materials such as thin thermoelectric film materials and their manufacturing technology brings new, more efficient thermoelectric semiconductor materials in rapid pace on the market. Of them, a person skilled in the art selects the best material for each application based on price and/or performance. A person skilled in the art naturally utilizes up-to-date professional literature when choosing the thermoelectric semiconductor materials or the structure of and the circuits for the thermoelectric elements.

Figure 5 shows the connections of the first and the second embodiment of the present invention to actuators and energy sources. Solar energy is transformed into electrical energy in a solar cell

I and moves through connections 14,15 to a voltage transformer 18. The other voltage source of this application is a thermoelectric element 6 from which electrical energy moves through connections 16, 17 to a voltage transformer 18. The voltage transformer transforms the voltage levels optimal to the electrical network 28 and to actuators through connection 33. Electrical networks and actuators can include electrical storages such as batteries, for example. The heat source of the heated medium 4 is solar energy both directly from the Sun and via solar mirrors 9. It is also possible to heat up the higher temperature medium in two other selectable heat sources, namely, solar mirror 32 and external heat source 31. The higher temperature medium is meant to be chosen in such way that the medium stays in liquid phase throughout operation. Thermal energy of the higher temperature medium 4 of this embodiment is transferred through juncture

I I into the higher temperature circuit of the heat exchanger 19 and from there to heat storage 22 and to a by-pass valve 25. The heated medium can be heated by both heat sources: an external heat source 31 and a solar mirror 32 either together or separately. The external heat source 31 can be chosen from a number of alternatives, for example: a chimney of a fireplace of a building, an exhaust pipe of a combustion engine, waste heat from industrial processes, a primus stove, or radioactive heat source. Electrical energy of the aforementioned and other thermoelectric apparatus can be directed to the voltage transformer 18. A bypass valve 25 which directs the higher temperature medium circulation past the heat storage does that when the solar thermal energy absorbed in the embodiment is sufficient for the temperature of the hot side of the thermoelectric semiconductor. The higher temperature pump 23 transfers the heated medium 4 from the pump to the embodiment through the joint 10. The low-temperature medium 8 of the application transfers through joint 13 to the low-temperature circulation of the heat exchanger 19, from there the medium transfers to the heat exchanger 20. From the heat exchanger 20, thermal energy transfers to the heated water 21. From the heat exchanger 20, the medium transfers to the heat exchanger 29 where thermal energy is transferred to thermal store 30. The purpose of the thermal store is to utilize thermal energy entering from the heated water and to cool the medium in order to make the temperature of the colder side of the thermal element 6 as low as possible. There are a number of thermal stores 30 such as the heat-storing parts of ground-source, water-source, and air-source heat pumps, swimming pools, water reservoirs of greenhouses, and sea, lake and river water in water-borne vessels. From the heat exchanger 29, the medium moves to the pump 27 of the lower temperature medium from where the medium transfers to the embodiment through joint 12. The water tank has a cold water input 27 and a hot water output 26.

A measurement and control unit (MCU) 35 which measures parameters of equipment and parts thereof as well as controls actuators through connections la - 33a can also be added in the system as depicted in figure 5. There may be a number of sensors in which case they are connected to electrical connectors added to MCU. Data about the parameters of the equipment and parts thereof can be received through connector 34 of MCU. Also, equipment such as a weather station can be connected to MCU. Through connector 34 of MCU, its measurement and control parameters can be programmed in order to gain optimum functionality with different choices of materials and actuators. From the connector la, measurement information about the solar radiation intensity incident on the surface of the embodiment is received. From the connector 2a, measurement information about the state of the vacuum is received. From the connector 3a, measurement information about the temperature of the plate 3 is received. From the connector 4a, measurement information about the temperature of the heated medium 4 is received. From the connector 5a, measurement information about the temperature of the plate 5 is received. From the connector 6a, measurement information about the operation of the thermoelectric element structure is received. From the connector 7a, measurement information about the temperature of the core 7 is received. From the connector 8a, measurement information about the temperature of the heated medium 8 is received. From the connector 9a, measurement information about the solar radiation intensity incident on mirror 9 is received. From the connector 10a, measurement information about the flow velocity of the heated medium 4 entering the embodiment is received, and from the connector 11a, measurement information about the flow velocity of the heated medium 4 leaving the embodiment is received. From the connector 12a, measurement information about the flow velocity of the cooling medium 8 entering the joint 12 is received, and from the connector 13a, measurement information about the flow velocity of the cooling medium 8 leaving the joint 13 is received. From a difference in the flow velocities, a leak in the system can be detected. At the connector 14a, measurement information about the electrical current in terminal 14 of the solar cell and at the connector 15a, measurement information about the electrical current in terminal 15 is received. At the connector 15, measurement information about the electrical current in terminal 16 of the thermoelectric element 6 and at the connector 17a, measurement information about the electrical current in terminal 17 is received. Of these, the possible fault current information can be deduced. From the connector 18a, measured parameter information from the voltage transformer, such as electrical currents and voltages, is received. From the connector 19a, measurement information about the temperature of the heat exchanger 19 is received. From the connector 20a, measurement information about the temperature of the heat exchanger 20 is received. From the connector 21a, measurement information about the temperature of the heated water is received. From the connector 22a, measurement information about the temperature of the heat storage 22 is received. From the connector 27a, the rotational velocity of the circulation pump 27 of the cooling medium 8 is controlled. From the connector 24a, the measured flow velocity of the incoming water at the input 24 is received. The bypass valve 25 is controlled through the connector 25a. From the connector 26a, the measured flow velocity of the water leaving through the output 26 is received. The rotational velocity of the circulation pump 27 of the heated medium 4 is controlled through the connector 27a. From the connector 28a, measurement information about the parameters of the electrical network input 28 are received. From the connector 29a, measurement information about the temperature of the heat exchanger 29 is received. From the connector 30a, measurement information about the temperature of the heat storage 30 is received. From the connector 31a, measurement information about the temperature of the heat source 31 is received. From the connector 32a, measurement information about the solar light intensity incident on solar mirror 32 is received. From the connector 33a, measurement information about the parameters of the voltage transformer 18 for MCU 35 is received.

In the second embodiment of the present invention, the structure and the operation are otherwise equal to the first embodiment, but solar cell is not used as the surface layer 1, but some other material which lets the solar energy pass through is used to form the surface layer. Here, electrical energy is generated solely by the thermoelectric elements.

The structure of the third embodiment of the present invention is a cylindrical construction whose shape and dimensions are chosen according to the use of the application and the requirements of the operating environment. Figure 6 shows the cross-section of an apparatus according to the invention. Vacuum tube techniques commonly used in solar collectors can be used with this embodiment. As depicted in figure 6, the embodiment has been divided by an element 101 into parts generating electricity by a solar cell 1 and by a thermoelectric element 6. On the solar cell side, the surface layer is formed by a solar cell such as, for example, a window-glass solar cell or a dye-sensitized solar cell. Inside the solar cell 1, there is a vacuum 2. Inside the vacuum there is a core 7 and inmost is the cooling element 8, which in this case is the cooling medium 8. The surface of the core can be a microstructure which improves thermal conductivity. On the thermoelectric element side, the surface layer 1 is formed by material which lets the solar radiation pass through as in the embodiment two. Inside the surface layer 1 there is a vacuum 2. In the third layer, there is a thin plate 3 covered with black material which intensifies the absorption of the solar energy into the plate. The plate 3 can be for example copper or other thermally well conductive material. The coating on the plate 3 can also be a microstructure which intensifies thermal transfer. The fourth layer is formed by a heated element 4 which in this case is a heated medium 4. Fifth in the structure is a thin plate 5 which is coated with black material which intensifies the absorption of solar energy into the plate. The plate 5 can be for example copper or other thermally well conductive material. The coating on the plate 5 can also be a microstructure which intensifies thermal transfer. Sixth layer is a thermoelectric element 6. The structure of two different thermoelectric elements is shown in figures 2 and 3. The seventh layer inwards the embodiment is a core 7 and inmost in the apparatus is a cooling element 8 which in this case is a cooling medium 8.

Solar radiation intensity incident on both sides of the apparatus can be intensified with mirrors 9 both on the solar cell side as well as on the thermoelectric element side. Solar radiation intensity can be intensified also with lenses either together with mirrors or separately. There may be a number of mirrors and lenses and they can be directed towards the Sun passively or actively. The construction and the amount of mirrors and lenses are chosen according to the price and the intended energy density. Mirror and lens constructions necessary for the applications are not described here in more detail as a person skilled in the art can implement them based on professional literature.

Solar cell 1 receives solar energy as direct and scattered radiation and possibly also reflected in a mirror. Incident solar energy penetrates through the solar cell 1 which forms the surface layer and part of the solar energy is transformed into electrical energy. Below the solar cell 1, there is a vacuum, the purpose of which is to reduce conductive thermal losses. Solar energy is radiated from the solar cell 1 through the vacuum 2 to the core 7 and is conducted through the core 7 to the cooling medium 8. The cooling medium 8 also cools down the solar cell 1 to boost its efficiency. On the thermoelectric element 6 side of the embodiment, the solar energy penetrates through the material 1, radiates through the vacuum 3 and is absorbed by the black surface of the plate 3. The solar energy is then conducted through the plate 3 to the heated medium 4. The medium is a liquid chosen according to the operating environment and the requirements set by the structure of the embodiment. As an example, different ethylene compounds, glycol, mineral oils and water can function as the medium. Water is a good medium due to its good heat transfer capacity in working environments where there is no fear of freezing up and where water also does not boil. When water boils, heat transfer in the system is disturbed. Increasing the water pressure increases the boiling temperature, but high water pressure poses a danger. Therefore, if the water pressure is increased necessary changes to the construction of the apparatus must be implemented simultaneously, and safety appliances that comply with requirements must be installed to the apparatus and its actuators. Thermal energy is then conducted through the plate 5 into the thermoelectric element 6 and it gives rise to temperature T_h in the thermoelectric element. The operating principles of two different thermoelectric elements 6 are presented in more detail in figures 2 and 3. Thermal energy conducted through the thermoelectric element then transfers to the core 7 and is conducted through it into the cooling medium 8. Now, lower temperature T_c is formed on this side of the thermoelectric element, and a temperature difference is formed between the cool side and the warm side of the thermoelectric element. The cooling medium 8 can be water which has a good heat transfer capacity. The operating environment must be such that there is no danger of freezing up. In colder environments, glycol, ethanol, or other suitable liquid is chosen based on price and/or other essential properties.

Figure 7 shows the connections of the third embodiment to actuators and energy sources. Solar energy is transformed into electrical energy in a solar cell 1 and moves through connections 14,15 to a voltage transformer 18. The other voltage source of this application is a thermoelectric element 6 from which electrical energy moves through connections 16, 17 to a voltage transformer 18. The voltage transformer transforms the voltage levels optimal to the electrical network 28 and to actuators through connection 33. Electrical networks and actuators can include electrical storages such as batteries, for example. The heat source of the heated medium 4 is solar energy both directly from the Sun and via solar mirrors 9. It is also possible to heat up the higher temperature medium in two other selectable heat sources, namely, solar mirror 32 and external heat source 31. The higher temperature medium is meant to be chosen in such way that the medium stays in liquid phase throughout operation. Thermal energy of the higher temperature medium of this embodiment is transferred through juncture 11 into the higher temperature circuit of the heat exchanger 19 and from there to heat storage 22 and to a by-pass valve 25. The heated medium can be heated by both heat sources: ah external heat source 31 and a solar mirror 32 either together or separately. The external heat source 31 can be chosen from a number of alternatives, for example: a chimney of a fireplace of a building, an exhaust pipe of a combustion engine, waste heat from industrial processes, a primus stove, or radioactive heat source. Electrical energy of the aforementioned and other thermoelectric apparatus can be directed to the voltage transformer 18. A bypass valve 25 which directs the higher temperature medium circulation past the heat storage does that when the solar thermal energy absorbed in the embodiment is sufficient for the temperature of the hot side of the thermoelectric semiconductor. The higher temperature pump 23 transfers the heated medium 4 from the pump to the embodiment through the joint 10. The low-temperature medium of the application transfers through joint 13 to the low-temperature circulation of the heat exchanger 19 from there the medium transfers to the heat exchanger 20. From the heat exchanger 20, thermal energy transfers to the heated water 21. From the heat exchanger 20, the medium transfers to the heat exchanger 29 where thermal energy is transferred to thermal store 30. The purpose of the thermal store is to utilize thermal energy entering from the heated water and to cool the medium in order to make the temperature of the colder side of the thermal element 6 as low as possible. There are a number of thermal stores 30 such as the heat-storing parts of ground-source, water-source, and air-source heat pumps, swimming pools, water reservoirs of greenhouses, and sea, lake and river water in water-borne vessels. From the heat exchanger 29, the medium moves to the pump 27 of the lower temperature medium from where the medium transfers to the embodiment through joint 12. The water tank has a cold water input 27 and a hot water output 26.

A measurement and control unit (MCU) 35 which measures parameters of equipment and parts thereof as well as controls actuators through connections la - 33a can also be added in the system as depicted in figure 7. There may be a number of sensors in which case they are connected to electrical connectors added to MCU. Data about the parameters of the equipment and parts thereof can be received through the connector 34 of MCU. Also equipment such as a weather station can be connected to the connector 34. Through the connector 34 of MCU, its measurement and control parameters can be programmed in order to gain optimum functionality with different choices of materials and actuators. From the connector la, measurement information about the solar radiation intensity incident on the surface of the embodiment is received. From the connector 2a, measurement information about the state of the vacuum is received. From the connector 3a, measurement information about the temperature of the plate 3 is received. From the connector 4a, measurement information about the temperature of the heated medium 4 is received. From the connector 5a, measurement information about the temperature of the plate 5 is received. From the connector 6a, measurement information about the operation of the thermoelectric element structure is received. From the connector 7a, measurement information about the temperature of the core 7 is received. From the connector 8a, measurement information about the temperature of the heated medium 8 is received. From the connector 9a, measurement information about the solar radiation intensity incident on mirror 9 is received. From the connector 10a, measurement information about the flow velocity of the heated medium 4 entering the embodiment is received, and from the connector 11a, measurement information about the flow velocity of the heated medium 4 leaving the embodiment is received. From the connector 12a, measurement information about the flow velocity of the cooling medium 8 entering the joint 12 is received and from the connector 13a, measurement information about the flow velocity of the cooling medium 8 leaving the joint 13 is received. From a difference in the flow velocities, a leak in the system can be detected. At the connector 14a, measurement information about the electrical current in terminal 14 of the solar cell and at the connector 15a, measurement information about the electrical current in terminal 15 is received. At the connector 15, measurement information about the electrical current in terminal 16 of the thermoelectric element 6 and at the connector 17a, measurement information about the electrical current in terminal 17 is received. Of these, the possible fault current information can be deduced. From the connector 18a, measured parameter information from the voltage transformer, such as electrical currents and voltages, is received. From the connector 19a, measurement information about the temperature of the heat exchanger 19 is received. From the connector 20a, measurement information about the temperature of the heat exchanger 20 is received. From the connector 21a, measurement information about the temperature of the heated water is received. From the connector 22a, measurement information about the temperature of the heat storage 22 is received. From the connector 23a, the rotational velocity of the circulation pump 27 of the cooling medium 8 is controlled. From the connector 24a, the measured flow velocity of the incoming water at the input 24 is received. The bypass valve 25 is controlled through the connector 25a. From the connector 26a, the measured flow velocity of the water leaving through the output 26 is received. The rotational velocity of the circulation pump 27 of the cooling medium 8 is controlled through the connector 27a. From the connector 28a, measurement information about the parameters of the electrical network input 28 are received. From the connector 29a, measurement information about the temperature of the heat exchanger 29 is received. From the connector 30a, measurement information about the temperature of the heat storage 30 is received. From the connector 31a, measurement information about the temperature of the heat source 31 is received. From the connector 32a, measurement information about the solar light intensity incident on solar mirror 32 is received. From the connector 33a, measurement information about the parameters for MCU 35 is received. The structure of the fourth embodiment of the present invention is a planar construction whose shape and dimensions are chosen according to the use of the application and the requirements of the operating environment. Figure 8 shows the cross-section of an apparatus according to the invention. Surface 1 comprises a solar cell as, for example, a window-glass solar cell or a dye-sensitized solar cell. Below the solar cell, there is a thin plate 3 covered with black material which intensifies the absorption of the solar energy into the plate. Plate 3 can be for example copper or other thermally well conductive material. The surface of the plate 3 can be a microstructure which improves thermal conductivity. The fourth layer is a heated element, which in this case is a heated medium 4. Fifth in the structure, there is a thin plate covered with black material which intensifies the absorption of the solar energy into the plate. The plate 5 can be, for example, copper or other thermally well conductive material. The surface of the plate 5 can be a microstructure which improves thermal conductivity. The sixth layer is a thermoelectric component 6. The seventh layer inwards the embodiment is a core 7. The surface of the core can be a microstructure which improves thermal conductivity. Inmost in the apparatus is a cooling element which in this case is a cooling medium 8. Solar radiation intensity incident on the apparatus can be intensified with mirrors as a mirror 9 outside the embodiment. Solar radiation intensity can be intensified also with lenses either together with mirrors or separately. There may be a number of mirrors and lenses, and they can be directed towards the Sun passively or actively. The construction and the amount of mirrors and lenses are chosen according to the price and the intended energy density. Mirror and lens constructions necessary for the applications are not described here in more detail as a person skilled in the art can implement them based on professional literature.

Solar cell 1, topmost in the structure, receives solar energy as direct and scattered radiation and possibly also reflected in a mirror as the mirror 9. Incident solar energy penetrates through the solar cell 1 which forms the surface layer and part of the solar energy is transformed into electrical energy. Solar energy transfers from the solar cell 1 to the surface of the plate 3. The solar energy is then conducted through the plate 3 to the heated medium 4. The medium is a liquid chosen according to the operating environment and the requirements set by the structure of the embodiment. As an example, different ethylene compounds, glycol, mineral oils and water can function as the medium Water is a good medium due to its good heat transfer capacity in working environments where there is no fear of freezing up and also where water does not boil. When water boils and is possibly vaporized, its heat transfer properties are disturbed. Increasing the water pressure requires changes to be implemented in the construction of the apparatus and safety appliances that comply with requirements to be installed to the apparatus and its actuators. Thermal energy is then conducted through the plate 5 into the thermoelectric element 6 and gives rise to temperature T_h in the thermoelectric element. Thermal energy conducted through the thermoelectric element is then conducted to the core 7 and through it into the cooling medium 8. Now, lower temperature T_c is formed on this side of the thermoelectric element and a temperature difference is formed across the thermoelectric element between the cool side, and the warm side. The cooling medium 8 can be water which has a good heat transfer capacity. The operating environment must be such that there is no danger of freezing up. In colder environments, glycol, ethanol, or other liquid is used whose properties comply with the application at hand. Solar energy is transformed into electrical energy in a solar cell 1 and moves through connections 14,15 to a voltage transformer 18. The other voltage source of this application is a thermoelectric element 6 from which electrical energy moves through connections 16, 17 to a voltage transformer 18. The voltage transformer transforms the voltage levels optimal to the electrical network 28 and to actuators through connection 33. Electrical networks and actuators can include electrical storages such as batteries, for example. The heat source of the heated medium 4 is solar energy both directly from the Sun and via solar mirrors as the mirror 9. It is also possible to heat up the higher temperature medium in two other selectable heat sources, namely, solar mirror 32 and external heat source 31. The higher temperature medium is meant to be chosen in such way that the medium stays in liquid phase throughout operation. Thermal energy of the higher temperature medium of this embodiment is transferred through juncture 11 into the higher temperature circuit of the heat exchanger 19 and from there to heat storage 22 and to a by-pass valve 25. The heated medium 4 can be heated by both heat sources: an external heat source 31 and a solar mirror 32 either together or separately. The external heat source 31 can be chosen from a number of alternatives, for example: a chimney of a fireplace of a building, an exhaust pipe of a combustion engine, waste heat from industrial processes, a primus stove, or a radioactive heat source. Electrical energy of the aforementioned and other thermoelectric apparatus can be directed to the voltage transformer 18. A bypass valve 25 which directs the higher temperature medium circulation past the heat storage does that when the solar thermal energy absorbed in the embodiment is sufficient for the temperature of the hot side of the thermoelectric semiconductor. The higher temperature pump 23 transfers the heated medium 4 from the pump to the embodiment through the joint 10. The low-temperature medium 8 of the application transfers through joint 13 to the low-temperature circulation of the heat exchanger 19, from there the medium transfers to the heat exchanger 20. From the heat exchanger 20, thermal energy transfers to the heated water 21. From the heat exchanger 20, the medium transfers to the heat exchanger 29 where thermal energy is transferred to thermal storage 30. The purpose of the thermal storage is to utilize thermal energy entering from the heated water and to cool the medium in order to make the temperature of the colder side of the thermal element 6 as low as possible. There are a number of thermal storages such as the heat-storing parts of ground-source, water-source, and air-source heat pumps, swimming pools, water reservoirs of greenhouses, and sea, lake and river water in water-borne vessels. From the heat exchanger 29, the medium moves to the pump 27 of the lower temperature medium from where the medium transfers to the embodiment through joint 12. The water tank has a cold water input 27 and a hot water output 26.

A measurement and control unit (MCU) 35 which measures parameters of equipment and parts thereof as well as controls actuators through connections la - 33a can also be added in the system as depicted in figure 9. There may be a number of sensors in which case they are connected to electrical connectors added to MCU. Data about the parameters of the equipment and parts thereof can be received through connector 34 of MCU. Equipment such as a weather station can be connected to the connector 34 of the MCU. Through the connector 34 of the MCU, its measurement and control parameters can be programmed in order to gain optimum functionality with different choices of materials and actuators. From the connector la, measurement information about the solar radiation intensity is received. From the connector 3a, measurement information about the temperature of the plate 3 is received. From the connector 4a, measurement information about the temperature of the heated medium 4 is received. From the connector 5a, measurement information about the temperature of the plate 5 is received. From the connector 6a, measurement information about the operation of the thermoelectric element structure is received. From the connector 7a, measurement information about the temperature of the core 7 is received. From the connector 8a, measurement information about the temperature of the heated medium is received. From the connector 9a, measurement information about the solar radiation intensity incident on mirror 9 is received. From the connector 10a, measurement information about the flow velocity of the heated medium 4 entering the embodiment is received and from the connector 1 la, measurement information about the flow velocity of the heated medium 4 leaving the embodiment is received. From the connector 12a, measurement information about the flow velocity of the cooling medium 8 entering the joint 12 is received and from the connector 13a, measurement information about the flow velocity of the cooling medium 8 leaving the joint 13 is received. From a difference in the flow velocities, a leak in the system can be detected. At the connector 14a, measurement information about the electrical current in terminal 14 of the solar cell and at the connector 15a, measurement information about the electrical current in terminal 15 are received. At the connector 16a, measurement information about the electrical current in terminal 16 of the thermoelectric element 6 and at the connector 17a, measurement information about the electrical current in terminal 17 of the thermoelectric element 6 are received. Of these, the possible fault current information can be deduced. From the connector 18a, measured parameter information from the voltage transformer, such as electrical currents and voltages, is received. From the connector 19a, measurement information about the temperature of the heat exchanger 19 is received. From the connector 20a, measurement information about the temperature of the heat exchanger 20 is received. From the connector 21a, measurement information about the temperature of the heated water is received. From the connector 22a, measurement information about the temperature of the heat storage 22 is received. From the connector 23a, the rotational velocity of the circulation pump 23 of the heated medium 4 is controlled. From the connector 24a the measured flow velocity of the incoming water at the input 24 is received. The bypass valve 25 is controlled through the connector 25a. From the connector 26a, the measured flow velocity of the water leaving through the output 26 is received. The rotational velocity of the circulation pump 27 of the cooling medium 8 is controlled through the connector 27a. From the connector 28a, measurement information about the parameters of the electrical network input 28 are received. From the connector 29a, measurement information about the temperature of the heat storage 29 is received. From the connector 30a, measurement information about the temperature of the heat storage 30 is received. From the connector 31a, measurement information about the temperature of the heat source 31 is received. From the connector 32a, measurement information about the solar light intensity incident on solar mirror 32 is received. From the connector 33a, measurement information about the parameters for MCU 35 is received.

In the fifth embodiment of the present invention, the structure and the operation are otherwise equal to the fourth embodiment, but solar cell is not used as the surface layer 1, but some other material which lets the solar energy pass through is used to form the surface layer. Here, electrical energy is generated solely by the thermoelectric elements. Figure 10 shows the sixth embodiment which is a planar construction and whose shape and dimensions are chosen according to the use of the application and the requirements of the operating environment The embodiment has been divided by an element 102 into parts generating electricity by a solar cell 1 and by a thermoelectric element 6. On the solar cell side, the surface layer is formed by a solar cell such as, for example, a window-glass solar cell or a dye-sensitized solar cell. Below the solar cell 1, there is a core 7, and inmost is the cooling element 8, which in this case is the cooling medium 8. The surface of the core can be a microstructure which improves thermal conductivity. On the thermo-electric element side, the surface layer 1 is formed by material which lets the solar radiation pass through as in the embodiments two and three. In the second layer, there is a thin plate 3. The plate 3 can be for example copper or other thermally well conductive material. The plate 3 can be covered with black material which intensifies the absorption of the solar energy into the plate. The coating on the plate 3 can also be a microstructure which improves thermal transfer. The fourth layer is formed by a heated element

4 which in this case is a heated medium 4. Fifth in the structure is a thin plate 5 which is coated with black material which intensifies the absorption of solar energy into the plate. The plate 5 can be for example copper or other thermally well conductive material. The coating on the plate

5 can also be a microstructure which improves thermal transfer. Sixth layer is a thermoelectric element 6. The structure of two different thermoelectric elements is shown in figures 2 and 3.

The seventh layer inwards the embodiment is a core 7, and inmost in the apparatus is a cooling element 8 which in this case is a cooling medium 8. The core 7 can also be coated by a microstructure which improves thermal transfer. Solar radiation intensity incident on both sides of the apparatus can be intensified with mirrors as the mirror 9. Solar radiation intensity can be intensified also with lenses either together with mirrors or separately. There may be a number of mirrors and lenses, and they can be directed towards the Sun passively or actively. The construction and the amount of mirrors and lenses are chosen according to the price and the intended energy density. Mirror and lens constructions necessary for the applications are not described here in more detail as a person skilled in the art can implement them based on professional literature. Solar cell 1 receives solar energy as direct and scattered radiation and possibly also reflected in a mirror. Incident solar energy penetrates through the solar cell 1 which forms the surface layer and part of the solar energy is transformed into electrical energy. Solar energy is transformed to the core 7 and is conducted through the core 7 to the cooling medium 8. The cooling medium 8 also cools down the solar cell 1 to boost its efficiency. On the thermoelectric element 6 side of the embodiment, the solar energy penetrates through the material land is conducted to the black surface of the plate 3. The solar energy is then conducted through the plate 3 to the heated medium 4. The medium is a liquid chosen according to the operating environment and the requirements set by the structure of the embodiment. As an example, different ethylene compounds, glycol, mineral oils and water can function as the medium. Water is a good medium due to its good heat transfer capacity in working environments where there is no fear of freezing up and where water also does not boil. When water boils, heat transfer in the system is disturbed. Increasing the water pressure increases the boiling temperature but high water pressure poses a danger. Therefore, if the water pressure is increased necessary changes to the construction of the apparatus must be implemented simultaneously and safety appliances that comply with requirements must be installed to the apparatus and its actuators. Thermal energy is then conducted through the plate 5 into the thermoelectric element 6 and it gives rise to temperature T_h in the thermoelectric element. The operating principles of two different thermoelectric elements 6 are presented in more detail in figures 4 and 5. Thermal energy conducted through the thermoelectric element then transfers to the core 7 and is conducted through it into the cooling medium 8. Now, lower temperature T_c is formed on this side of the thermoelectric element and a temperature difference is formed between the cool side and the warm side of the thermoelectric element. The cooling medium 8 can be water which has a good heat transfer capacity. The operating environment must be such that there is no danger of freezing up. In colder environments, glycol, ethanol, or other suitable liquid is chosen based on price and/or other essential properties.

Figure 11 shows the connections of the sixth embodiment to actuators and energy sources. Solar energy is transformed into electrical energy in a solar cell 1 and moves through connections 14,15 to a voltage transformer 18. The other voltage source of this application is a thermoelectric element 6 from which electrical energy moves through connections 16, 17 to a voltage transformer 18. The voltage transformer transforms the voltage levels optimal to the electrical network 28 and to actuators through connection 33. Electrical networks and actuators can include electrical storages such as batteries, for example. The heat source of the heated medium 4 is solar energy both directly from the Sun and via solar mirrors 9. It is also possible to heat up the higher temperature medium in two other selectable heat sources, namely, a solar mirror 32 and an external heat source 31. The higher temperature medium is meant to be chosen in such way that the medium stays in liquid phase throughout operation. Thermal energy of the higher temperature medium of this embodiment is transferred through juncture 11 into the higher temperature circuit of the heat exchanger 19 and from there to heat storage 22 and to a by-pass valve 25. The heated medium can be heated by both heat sources: an external heat source 31 and a solar mirror 32 either together or separately. The external heat source 31 can be chosen from a number of alternatives, for example: a chimney of a fireplace of a building, an exhaust pipe of a combustion engine, waste heat from industrial processes, a primus stove, or radioactive heat source. Electrical energy of the aforementioned and other thermoelectric apparatus can be directed to the voltage transformer 18. A bypass valve 25 which directs the higher temperature medium circulation past the heat storage does that when the solar thermal energy absorbed in the embodiment is sufficient for the temperature of the hot side of the thermoelectric semiconductor. The higher temperature pump 23 transfers the heated medium 4 from the pump to the embodiment through the joint 10. The low-temperature medium of the application transfers through joint 13 to the low-temperature circulation of the heat exchanger 19 from there the medium transfers to the heat exchanger 20. From the heat exchanger 20, thermal energy transfers to the heated water 21. From the heat exchanger 20, the medium transfers to the heat exchanger 29 where thermal energy is transferred to thermal store 30. The purpose of the thermal store is to utilize thermal energy entering from the heated water and to cool the medium in order to make the temperature of the colder side of the thermoelectric element 6 as low as possible. There are a number of thermal stores 30 such as the heat-storing parts of ground-source, water-source, and air-source heat pumps, swimming pools, water reservoirs of greenhouses, and sea, lake and river water in water-borne vessels. From the heat exchanger 29, the medium moves to the pump 27 of the lower temperature medium from where the medium transfers to the embodiment through joint 12. The water tank 21 has a cold water input 27 and a hot water output 26. A measurement and control unit (MCU) 35 which measures parameters of equipment and parts thereof as well as controls actuators through connections la - 33a can also be added in the system as depicted in figure 11. There may be a number of sensors in which case they are connected to electrical connectors added to MCU 35. Data about the parameters of the equipment and parts thereof can be received through and equipment such as a weather station can be connected to the connector 34 of MCU. Through the connector 34 of MCU its measurement and control parameters can be programmed in order to gain optimum functionality with different choices of materials and actuators. From the connector la, measurement information about the solar radiation intensity incident on the surface 1 of the embodiment is received. From the connector 3a, measurement information about the temperature of the plate 3 is received. From the connector 4a, measurement information about the temperature of the heated medium 4 is received. From the connector 5a, measurement information about the temperature of the plate 5 is received. From the connector 6a, measurement information about the operation of the thermoelectric element structure is received. From the connector 7a, measurement information about the temperature of the core 7 is received. From the connector 8a, measurement information about the temperature of the heated medium 8 is received. From the connector 9a, measurement information about the solar radiation intensity incident on mirror 9 is received. From the connector 10a, measurement information about the flow velocity of the heated medium 4 entering the embodiment is received, and from the connector 11a, measurement information about the flow velocity of the heated medium 4 leaving the embodiment is received. From the connector 12a, measurement information about the flow velocity of the cooling medium 8 entering the joint 12 is received and from the connector 13a, measurement information about the flow velocity of the cooling medium 8 leaving the joint 13 is received. From a difference in the flow velocities, a leak in the system can be detected. At the connector 14a, measurement information about the electrical current in terminal 14 of the solar cell and at the connector 15a, measurement information about the electrical current in terminal 15 are received. At the connector 15, measurement information about the electrical current in terminal 16 of the thermoelectric element 6 and at the connector 17a, measurement information about the electrical current in terminal 17 are received. Of these, the possible fault current information can be deduced. From the connector 18a, measured parameter information from the voltage transformer, such as electrical currents and voltages, is received. From the connector 19a, measurement information about the temperature of the heat exchanger 19 is received. From the connector 20a, measurement information about the temperature of the heat exchanger 20 is received. From the connector 21a, measurement information about the temperature of the heated water is received. From the connector 22a, measurement information about the temperature of the heat storage 22 is received. From the connector 23a, the rotational velocity of the circulation pump 23 of the heated medium 4 is controlled. From the connector 24a the measured flow velocity of the incoming water at the input 24 is received. The bypass valve 25 is controlled through the connector 25a. From the connector 26a, the measured flow velocity of the water leaving through the output 26 is received. The rotational velocity of the circulation pump 27 of the cooling medium 8 is controlled through the connector 27a. From the connector 28a, measurement information about the parameters of the electrical network input 28 are received. From the connector 29a, measurement information about the temperature of the heat exchanger 29 is received. From the connector 30a, measurement information about the temperature of the heat storage 30 is received. From the connector 31a, measurement information about the temperature of the heat source 31 is received. From the connector 32a, measurement information about the solar light intensity incident on solar mirror 32 is received. From the connector 33a, measurement information about the parameters for MCU 35 is received.

Within the scope of the present invention also other applications differing from the embodiments described above may be considered.

Claims

Patent claims

1. Solar power plant generating electricity and heat, comprising one or more elements generating electricity (1,6), a heated element (4), and a cooling element (8), so that at least one of the elements generating electricity comprises at least one thermoelectric element (6), is characterized by arrangement where a heated element (4), one or more elements generating electricity (1,6), and a cooling element are laid one on the other in the principal direction.

2. Solar power plant, as claimed in claim 1 is characterized in that a heated element (4) and a cooling element (8) are liquid media.

3. Solar power plant, as claimed in claim 2 is characterized in that a heated element (4) and a cooling element (8) are comprised of liquid circulation separated from each other.

4. Solar power plant, as claimed in any one of the claims 1-3 is characterized in that at least one of the elements generating electricity (1) comprises a solar cell, such as window-glass solar cell or dye-sensitized solar cell.

5. Solar power plant, as claimed in any one of the claims 1-4 is characterized by comprising at least one reflector (9) and/or a lens that is arranged to enhance the intensity of solar radiation.

6. Solar power plant, as claimed in any one of the claims 1-5 is characterized in that the layers are flat-plate and the principal direction is perpendicular to planes; or the layers are cylindrical and the principal direction is a direction of cylinder radius; or the layers have a form of cylinder segment such as a half cylinder, and the principal direction is a direction of symmetry axis of cylinder segment.

7. Energy production system is characterized by comprising a solar power plant, as claimed in any one of the claims 1-6.

8. Energy production system, as claimed in claim 7 is characterized by comprising an external heat source (31), such as, for example a furnace chimney, an exhaust pipe of combustion engine, an industrial process producing waste heat, a camp cooker, a radioactive heat source or a solar mirror.

9. The method for converting solar energy to electricity and heat is characterized in that a heated element (4), at least one or several elements generating electricity (1,6) and a cooling element (8) are laid one on the other in the principal direction, and at least one of the elements generating electricity is comprised of at least one thermoelectric element (6).