Method for operating a receiver, receiver for implementing the method and manufacturing method for a receiver

Abstract

The receiver (25, 50, 100, 120) according to the application is provided with a heating region (26) for heating a heat-transporting medium and a transport assembly (29) for transporting the medium through the heating region, the heating region having an optical opening (3) for solar radiation and an absorber (27, 51) arranged in the path of the incident solar radiation, which absorbs the solar radiation, wherein the absorber (27, 51) is configured as a black-body radiation assembly with reduced convection, and the transport assembly is configured for transporting a gas as heat-transporting medium. The receiver can thereby be configured more simply and more reliably.

Description

Technical Field

[0001] The present invention relates to a method for operating a receiver having a heating region for heating a heat-transferring medium and a transmission assembly for transmitting the medium through the heating region, wherein the heating region has an opening for solar radiation in the transmission path of the medium and an absorber for absorbing the solar radiation arranged in the path of the incident solar radiation; and a receiver for implementing the method having: a heating region for heating a heat-transferring medium having an opening for solar radiation and an absorber for absorbing the solar radiation arranged in the path of the incident solar radiation; a transmission assembly for transmitting the medium through the heating region; and a method for manufacturing a receiver having a heating region for heating a heat-transferring medium and a transmission assembly for transmitting the medium through the heating region, wherein the heating region has an optical opening for sunlight and an absorber for absorbing the sunlight arranged in the path of the incident sunlight. Background Technology

[0002] The receiver is used in solar power plants. The receiver receives concentrated solar radiation and thereby heats a heat-transferring medium, through which the acquired heat is utilized in subsequent technological processes. This heat is converted into mechanical work, for example, by driving turbines, for carrying out heat-requiring processes in industry or for heating, such as long-distance heating in residential areas.

[0003] Solar tower power plants primarily use receivers constructed as tube bundles, designed for temperatures up to 600°C and solar concentrators of 600. For even higher temperatures, spatially constructed receivers are mainly used, designed for solar concentrators of 600, 1000, or more. Such temperatures typically range above 600°C, reaching 800°C to 1000°C and above, and are soon capable of reaching a range of 1200°C to 1500°C. Such receivers can also be used (however on a smaller scale) in the case of dish concentrators. Currently, receivers are referred to as spatial receivers, whose dimensions are analogous in all three dimensions to those of tubular receivers, which are used in conjunction with grooved or trench collectors. Such tubular receivers have one dimension, namely the length, which is many times the cross-sectional dimension (width or height), with multiples ranging from tens to hundreds of times or more. The receiver for the trench collector is not constructed for the temperatures mentioned above because the trench-shaped concentrator is concentrated in two dimensions with respect to the receiver, whereas the field or butterfly concentrator of the heliostat in the tower power plant is concentrated in three dimensions.

[0004] Such receivers are known to those skilled in the art as volumetric receivers, which are also suitable for solar tower power plants, where the required temperatures exceeding 500°C or 1000°C, for example up to 1200°C, can be achieved. However, the high operating temperatures result in significant structural costs.

[0005] The volumetric receiver has an extended (loose, hence belonging to the "volumetric" receiver) absorber structure, which can be, for example, constructed of loosely braided wire or open-cell porous ceramic foam. Concentrated solar radiation then penetrates into the interior of the (loose) absorber structure and is absorbed there. The heat-transferring medium, such as air or a suitable reaction medium for subsequent reactors, is guided through the open-cell porous absorber structure and thereby absorbs heat by forced convection at the open-cell porous absorber structure. The absorber structure can also be constructed of a tubular structure, a grid structure graded in depth, or any structure with a large surface area, which facilitates the convective transfer of heat from the absorber structure to the heat-transferring medium as the heat-transferring medium flows through the absorber.

[0006] A volumetric receiver, for example, has become known through the REFOS project (Receiver for solar-hybridgas turbine and combined cycle systems; R. Buck, M. Abele, J. Kunberger, T. Denk, P. Heller and E. Lüpfert, in Journal de Physique IV France 9 (1999)), is described in detail below in conjunction with Figure 1.

[0007] Such a receiver has the following disadvantages: the absorber structure is costly to manufacture and the flow through the absorber may become unstable, especially due to undesirable temperature distributions during operation. Summary of the Invention

[0008] Accordingly, the object of the present invention is to provide an improved receiver.

[0009] The objective is achieved by the method according to the present invention.

[0010] By making the selected heat-transferring gas absorbent in the infrared band according to the method of the invention, and by adjusting the operating parameters so that a significant portion of the heat increase is achieved through absorption in the heat-transferring gas, a simplified conceptual design of the receiver can be realized, since heat transfer is achieved by less convection.

[0011] By constructing the absorption assembly with reduced convective blackbody radiation, the construction of the absorber is simplified, and thus the construction and operation of the receiver are simplified, because the absorber no longer needs to deliver the heat brought in by the solar radiation to the heat-transmitting gas in a convective manner at its depth.

[0012] The preferred embodiment has the features of the present invention. Attached Figure Description

[0013] The invention will now be described in detail with reference to the accompanying drawings.

[0014] in: Figure 1a A receiver based on existing technology is shown. Figure 1b Schematic illustration of having in Figure 1a A graph showing the temperature trend in the receiver. Figure 2 The receiver according to the invention is schematically shown in longitudinal section. Figure 3 Another embodiment of the receiver according to the invention is illustrated schematically; Figure 4 Schematic illustration with in Figure 2 A graph showing the temperature trend in the receiver; Figure 5 Another embodiment of the receiver according to the invention is illustrated schematically; Figure 6 A cross-sectional view schematically illustrating another embodiment of the receiver according to the invention is shown; Figure 7a and 7b Showing with according to Figure 2 and 3 A graph showing the temperature trend in the receiver according to the present invention; Figure 8a To c shows with according to Figure 2 and 3 A graph showing the efficiency of the receiver and the temperature of the absorbing surface according to the present invention; Figure 9 Another embodiment of the receiver according to the invention is illustrated schematically; Figure 10 This shows a view of another embodiment of the receiver according to the invention in a horizontal operating position; Figure 11a Show Figure 10 A cross-section of the annular space of the receiver; Figure 11b Show Figure 11aThe enlarged truncated segment; Figure 12 Shown in accordance with Figures 10 to 11b The receiver is configured according to the simulated temperature distribution; Figure 13 The steps of the method of operating a receiver according to the present invention are shown; and Figure 14 The steps of a method for manufacturing a receiver according to the present invention are shown. Detailed Implementation

[0015] Figure 1a A test assembly for a volumetric receiver 1 according to the RE-FOS project is shown. The receiver has a heating zone 2 for heating the heat-transferring medium (here, air), the heating zone having an opening 3 configured as a quartz window for radiation 4 from the sun or sunlight 4, and an absorber 5 arranged after the quartz window 3 in the path of the incident radiation 4 to absorb the radiation 4. In the illustrated embodiment, a transmission assembly 6 for transferring the heat-transferring medium through the heating zone 2 has an inlet 7 and an outlet 8, the medium having an entry temperature T. in The medium reaches the receiver 1 through the inlet and exits with the departure temperature T. out The ground leaves the receiver.

[0016] Via channel 9 on the edge side of the transmission component 6, with the entry temperature T in The air is directed to the end of the receiver 1, where it passes through a suitably constructed opening 10 into a distribution space 11 placed before the absorber 5, is distributed, and then flows through the absorber 5, where it is heated by convection and ultimately reaches a temperature T. out The air reaches the collection space 13 and from there reaches the outlet 8, through which it exits the receiver 1. The quartz window 3 is arched inward, so that the receiver 1 can operate at increased pressure, thereby allowing the heated air to be supplied under pressure to a downstream consumer, such as a turbine.

[0017] The space-saving absorber 5, constructed as a volumetric absorber and tracking the contour of the quartz window 3, has a number of finely braided wire layers into which sunlight 4 can penetrate deeply. This allows the absorber 5 to be heated throughout its entire depth, and the air flowing through the absorber is thus heated by convection to T. outAs mentioned above, conventional absorbers can be formed in other embodiments from open porous ceramic foams or other components with surfaces that are much larger than the air volume in the absorber, in order to achieve the required convective heat transfer.

[0018] An isolation section 12 surrounds the receiver 1. A secondary concentrator, omitted to reduce the visual burden, is connected to the receiver before the optical opening 3. This secondary concentrator concentrates the flow of solar radiation 4 onto the quartz window 3. To further reduce the visual burden, control devices for the receiver 1 and the transmission assembly 6 are also omitted, via which the operation of the receiver 1 or the introduction and extraction of air are appropriately regulated, as is known to those skilled in the art. A receiver of the REFOS receiver type shown can achieve an exit temperature T of 800°C. out In the case of ceramic absorbers, the exit temperature is 1000℃.

[0019] Figure 1b Chart 15 shows a temperature profile 16, which is combined with... Figure 1a The temperature profile of the air flowing through the receiver 1 is schematically illustrated. In section A, from the inlet 7 to the end of the channel 9 on the edge side, the air temperature is controlled from T... in A small convective heating occurs from T1 to T2 (part 17 of temperature curve 16). In section B, during the air's passage through the opening 10 in the absorber 5, a related and convective first heating from T1 to T2 is achieved (part 18 of temperature curve 16). In section C, that is, in the distribution space 11, the air is heated absorptively, but only slightly, because the air, as a gas mixture, contains, for example, a small amount of CO2 (or other gases), which absorbs in the infrared range, while the rest is substantially transparent to infrared radiation (part 19 of temperature curve 16). Finally, the air flows through the absorber 5 in section D, where it is convectively heated to temperature T4, corresponding to the exit temperature T. out (A portion 20 of the temperature curve 16). In section E, the air reaches the outlet 8 through the gathering space 13, wherein the small absorption temperature increase is obtained through the gas components that act as infrared absorbers. From T in To T out The temperature jump is primarily determined by convection. Therefore, according to Figure 15, the (actual) ratio of the temperature increase from convection to the temperature increase from absorption is greater than 5:1.

[0020] Figure 2A schematic embodiment of a receiver 25, constructed as a spatial receiver according to the invention, is shown, the receiver having a heating region with an opening 3 for solar radiation, such as a quartz window, and a plate-shaped absorber 27. An absorber space 28 forming the heating region is provided between the quartz window 3 and the absorber 27, the absorber space being through which the heat-transferring medium flows from right to left, i.e., against the direction of the absorber 27, corresponding to the drawn arrow. For this purpose, the transmission device 29 has an inlet pipe 30 for the heat-transferring medium arranged around the quartz window 3, the inlet pipe leading into the absorber space 28; and an outlet pipe 31 centrally located after the absorber 27. For the sake of simplicity, the receiver's insulating portion is also omitted here in the following figures.

[0021] According to the invention, the absorber 27 is configured as a blackbody radiation assembly, that is, the absorber has a surface 27' arranged in the path of incident sunlight or incident solar radiation 4 that absorbs said radiation, the surface being configured such that the absorber is operablely heated by the solar radiation 4 incident on the surface 27' and then emits infrared radiation accordingly through its surface 27' into the absorber space 28.

[0022] Thus, the absorber 27 emits a significant portion of its thermal power as infrared radiation into the absorber space 28, where the heat transfer medium flowing into the absorber space relates to T. out The medium is heated, in a largely or primarily absorbing manner, before it reaches the absorber space.

[0023] The actual structure radiates only approximately as if it were an ideal blackbody. Currently, a "blackbody radiation assembly" is understood to be one in which the incident solar radiation 4 is absorbed as much as possible at the surface of the absorber (i.e., in principle only a small amount penetrates into the absorber, unlike known volumetric absorbers), thereby heating the surface to a high temperature, and thus radiating into the absorber space 28 at that high temperature within the blackbody, with a spectrum different from the solar radiation. The majority of the blackbody radiation emitted into the absorber space 28 is in the infrared range up to (or above) the temperature of the absorber 27 up to 2000ºK, that is, at frequencies deeper than visible light, as mentioned.

[0024] In other words, the absorber according to the invention is configured to be cooled to such an extent by its blackbody radiation that a ratio χ can be achieved (see description below).

[0025] This eliminates the need for costly, depth-graded absorber structures, particularly for volumetric receivers, which absorb incident solar radiation or radiation from the sun at their depth by means that the radiation is at least partially scattered internally and increasingly absorbed after multiple reflections. This also eliminates the complex thermal problems typically present in such absorber structures. Furthermore, the simple shape of the absorber space 28 provides the preconditions for the flow of heat-transferring medium from the opening 3 to the opposite absorber 27, the medium continuously heating towards the absorber. Solar radiation 4 preferably strikes the absorber 27 directly (i.e., without reflection on the walls of the absorber space 28). The flow of the heat-transferring medium and the sunlight striking the absorber directly through the opening share a common direction. Despite complex thermodynamic effects during operation, this results in a stratified heat distribution within the absorber space 28, with layers extending across its cross-section.

[0026] Thus, the heat-transferring medium undergoes continuous heating towards the absorber 27, with the coldest region of the absorber located at the opening 3, thereby minimizing reflection losses from the opening 3. Similarly, the hottest region of the heat-transferring medium is located at the absorber 27, i.e., furthest from the opening 3, so its (blackbody) infrared radiation is captured by the heat-transferring medium layer between it and the opening 3, i.e., it does not reach or only minimally reaches the opening 3, which further improves the efficiency of the receiver according to the invention. Since the heat-transferring medium flows at least substantially uniformly towards the absorber 27 along the cross-section of the absorber space 28, the hottest layer of the medium does not diffuse towards the opening 3 due to blackbody infrared radiation from the region adjacent to the absorber 27 and the heat-transferring medium.

[0027] The absorber 27 is further preferably constructed in a manner with minimal convection, meaning that, for example, it can be easily traversed, and the convection characteristics for improving heat exchange are not important. This also eliminates the need for a construction scheme that maximizes convection for the traversing medium, i.e., a structure with a surface area larger than the traversing medium, which is necessary for the most efficient heat exchanger. Such a surface would be costly and expensive to manufacture for high efficiency and would cause a significant pressure drop in the traversing medium during operation, which is detrimental to the efficiency of the corresponding receiver.

[0028] It should be noted that, at the absorber 2, a certain degree of convective heat transfer through contact with the heat exchange medium is naturally unavoidable, especially... Figure 2In the illustrated embodiment, the absorber forms a wall section of the absorber space 28 at that location. Like any heat transfer, heat transfer via corresponding convection towards the gas carrying heat is desirable in that it does not incur structural costs or, for example, increase flow resistance—correspondingly, the outlet temperature T... out A large or primary portion (see below) is based on absorption, thus enabling a simplified construction of receiver 25. This simplified construction of absorber 27, in particular as mentioned above, opens up the feasibility of cost-effective manufacturing for (low-cost receivers for high temperatures) and also enables, for example, more stable operation in terms of thermal properties (temperature distribution on said absorber 27), resulting in improved industrial applicability of said receiver.

[0029] According to the present invention, a receiver is provided having a heating region for heating a medium that transmits heat, the heating region having an opening for solar radiation and an absorber arranged in the path of the incident solar radiation to absorb the radiation; and a transmission assembly for transmitting the medium through the heating region, wherein an absorber space for heating the medium that transmits heat is provided outside the absorber, and the absorber is configured as a blackbody radiation assembly with low convection, and the transmission assembly is configured for transmitting a gas as the medium that transmits heat.

[0030] Preferably, the absorber of the blackbody radiation assembly, which is configured to have low convection, is configured for the flow of the heat-transferring gas and is further preferably opposite the optical opening 3.

[0031] More preferably, such as Figure 2 As shown, the absorber space 28 is disposed between the opening 3 for solar radiation and the absorber 27, wherein the ratio χ is the ratio of the temperature increase (T3-T2) achieved by the gas after passing through the absorber through absorption of radiation from the absorber 27 in the absorber space 28 to the total temperature increase (T4-T2) achieved through absorption and convection at the absorber 27. The gas is then drawn into the accumulation space 33 when it has just passed through the absorber 27 and thus reaches the accumulation space 33, or when it is just laterally removed at the location of the absorber 27 (e.g., by means of...). Figure 5 The opening 92''' or 93''') passes through the absorber 27, wherein, naturally, in a particular embodiment, two feasible schemes can be provided simultaneously.

[0032] In another embodiment, not shown in the figures, the accumulation space 33 on the back side of the absorber 27 is configured as an additional absorber space. In the case of an absorber that is at least partially gas-sealed (see below), gas is guided around the absorber to the back side of the absorber and then guided away from the back side.

[0033] Then, the heat-transferring gas, which has been heated by absorption and convection, flows through the additional absorber space and is additionally heated by absorption and convection, preferably according to the invention, at a temperature ratio χ ≥ 0.3. This ultimately allows for an increase in the radiating surface 27' and thereby optimizes the heat transfer that occurs by absorption.

[0034] Thus, the heating zone has two absorber spaces with a common absorber, wherein the ratio χ is set for one or both absorber spaces.

[0035] Furthermore, according to the present invention, a gas or gas mixture that performs infrared absorption is used as a heat transfer medium, the gas or gas mixture absorbing in the infrared frequency band. Such gases are, for example, heteropolar gases, preferably CO2, water vapor, CH4, NH3, CO, SO2, SO3, HCl, NO and NO2, or mixtures thereof, such as a mixture of water vapor and CO2. When using such a gas, a greenhouse effect that can be used or utilized by the receiver 25 is ultimately obtained, because the gas is highly transparent to visible light, which thus substantially reaches the absorber 27, but is not very transparent to almost opaque to the infrared radiation of the absorber, so that the infrared radiation is absorbed before the absorber 27 and involves T. out The gas is heated to a significant or primary degree. It should be noted that real gases do not absorb visible or infrared radiation uniformly at all frequencies or are transparent to them, but rather vary in intensity, particularly within specific frequency bands for a given gas. Additionally, the absorption decreases with distance from the radiation source. Thus, the above statements regarding radiation absorption or transparency, such as "highly transparent" or "not very transparent to almost opaque," are meaningless.

[0036] It should be further noted that natural solar radiation also has a certain share of the infrared band, provided that the radiation passes through the atmosphere to the Earth's surface. Because the heating region is constructed to be relatively opaque to almost opaque with respect to infrared frequencies, this (relatively small) share directly, rather than indirectly, contributes to the heating of the heat-transferring fluid via the absorber 27 (thus most efficiently according to the invention). This contrasts with conventional receivers, in which the infrared portion of solar radiation also substantially heats the absorber and is emitted primarily via convection to the heat-transferring fluid.

[0037] The absorber according to the invention can be constructed as an orifice plate, preferably a bi-orifice plate, or a simple planar grid structure. In the case of the orifice plate, the perforations are arranged in a pattern distributed over its extension, allowing the heat-transferring gas to flow through easily, while providing a sufficient or as many perforated plate surfaces as possible to absorb incident solar radiation and infrared re-radiation entering the absorber space. Additionally, the perforation arrangement can be designed for easy flowability, as the necessity of convection is eliminated, and reduced flow resistance is advantageous. Those skilled in the art can easily and ideally determine the perforation arrangement in specific circumstances. Similarly, for the grid structure or the bi-orifice plate with two plates parallel to each other, where the perforations of one plate are staggered relative to the perforations of the other plate, the absorber space receives the most coherent, radiating surface possible from the absorber, despite minimal convection of the heat-exchange gas. In this case, the gas is guided through the absorber. Alternatively, the absorber can also be configured as a gas-sealed system, wherein the gas is, for example, in... Figure 5 The gas flows laterally from the absorber space 26 as shown. The gas is then guided laterally through the absorber. Those skilled in the art can, in specific cases, arrange a mixing configuration such that a portion of the gas flows through the absorber and a portion flows laterally through the absorber. The absorber then has at least a partially gas-sealed surface and is preferably configured as a plate (with a completely gas-sealed surface when the gas is guided laterally through the absorber).

[0038] Suitable materials for the absorber possess not only high absorptivity to solar radiation but also high emissivity to infrared radiation, which can be further enhanced (if desired) by suitable texturing of the surface 27', such as V-grooves, pyramidal portions extending into or out of the surface, or other radiation conditions. Furthermore, high temperature (alternating) resistance and corrosion resistance (e.g., against oxidation at high temperatures due to water vapor or CO2) are prerequisites. Suitable materials are not only high-temperature ceramics such as silicon carbide (SiC) but also fire-resistant structural materials, which can be selected by those skilled in the art, particularly regarding the specified temperature range.

[0039] In comparison Figure 2 The components are schematically modified in Figure 3 In another embodiment shown, the inlet pipe 30 ( Figure 2 The receiver 25 is not arranged around the quartz window 3, but rather behind the quartz window 3 or the opening for solar radiation, in the direction of the incident solar radiation 4. Therefore, the corresponding path for the gas used to transfer heat is not located in the plane of the quartz window 3, but at least directly behind it, that is, not on the surface of the receiver 25 facing the incident light. This eliminates the need for corresponding light shielding, wherein the opening 3 can be precisely measured according to the cross-section of the concentrated incident light.

[0040] A receiver according to the invention comprises: a heating region for heating a heat-transferring medium, the heating region having an opening for solar radiation and an absorber arranged in the path of the incident solar radiation to absorb the solar radiation; a transmission assembly for transmitting the medium through the heating region, wherein an absorber space for heating the heat-transferring medium is further provided, one end of the absorber being formed by the opening for solar radiation, and the other end being formed by an absorber opposite to the opening, such that solar radiation incident through the opening substantially completely strikes the absorber, and the absorber is configured as a radiation assembly acting in the absorber space; the transmission assembly is configured to transmit a gas as the heat-transferring medium, the gas in the opening region. However, the heat transfer medium is transmitted to the absorber space after the opening along the direction of incident radiation, and is discharged from the absorber space (only) in the region of the absorber. Thus, during operation, the heat transfer medium completely passes through the absorber space from the end with the opening to the other end with the absorber in the direction corresponding to the incident solar radiation. The heat transfer medium is mainly a gas that absorbs in the infrared band, and the size of the absorber space that works in conjunction with the absorber is set such that the temperature increase (T3-T2) of the heat transfer gas that absorbs in the infrared band during operation due to absorption in the absorber space is χ≥0.3 relative to the temperature increase (T4-T2) due to absorption and convection at the absorber.

[0041] Here, according to the choice of those skilled in the art, in a specific case, the receiver according to the invention can be constructed such that the temperature generated by the absorption of radiation from the absorber during transmission through the heated region increases such that the ratio χ of the temperature increase (T3-T2) achieved by the absorption of radiation from the absorber to the total temperature increase (T4-T2) achieved by the absorption of radiation from the absorber and convection at the absorber is ≥0.3, but particularly preferably up to ≥0.8 (see the description below for details).

[0042] This component is particularly capable of producing a stable temperature distribution during operation, with the temperature continuously rising towards the absorber 27, wherein this temperature distribution does not change significantly over time in the cross-section of the absorber space. The continuously rising temperature towards the absorber means that the layer of the heat-transferring gas adjacent to the opening or quartz window 3 has the lowest temperature, and therefore the least amount of heat reflection through the quartz window 3, which contributes to the high efficiency of the receiver according to the invention. The same temperature distribution along the cross-section of the absorber space allows the outlet nozzle 31 to be placed in an optimal location, for example, at the point where the temperature of the heat-transferring medium is highest; the outlet nozzle does not need to be like... Figure 2 The diagram illustrates, for example, the arrangement of the receiver along its longitudinal axis or centrally. For instance, when the receiver 25 is arranged at an angle on the solar tower, convection occurs within the heat transfer medium in the absorber space 28, thus the outlet pipe is not centrally located but offset upwards; see also the appendix below for further details. Figure 9 and 10 The explanation provided.

[0043] In any case, the component according to the invention can achieve a constant and stable temperature distribution in the receiver 25, and optimally minimize reflections by adapting to the window 3. Figure 4 Chart 40 is shown with temperature curve 41, which combines... Figure 2 or Figure 3 The temperature trend of the gas flowing through receiver 25 is schematically shown.

[0044] In section F, a portion 42 of the temperature curve shows the heat-transferring gas that performs infrared absorption from T. in Heating to T1 is performed in the following situations: at the receiver 25 Figure 2In the embodiment shown, the gas that acts as an infrared absorber, such as the air in the receiver 1 (Figure 1), should similarly be transported to the end side along the absorber space 28 (however, this is not necessarily the case). In section G, the air is heated by a small convection from T1 to T2 as the gas travels through the inlet nozzle 30 (part 43 of the temperature curve 41).

[0045] In section H, the infrared-absorbing gas flows through the absorber space 28 and is heated from T2 to T3 (a portion 44 of the temperature curve 41) by absorbing infrared radiation 32 (here utilizing the infrared component of solar radiation) from the absorber 27. The gas then flows through the absorber in section I and is heated from T3 to T4 (a portion 45 of the temperature curve 41) by convection. Finally, while the gas is in the accumulation space 33 and flowing towards the outlet nozzle 31, the infrared-absorbing gas is heated from T4 to the exit temperature T in section K. out Further absorption of heat (a portion 46 of the temperature curve 41). According to the invention, from T in To T out Temperature jumps are largely or primarily determined by absorption.

[0046] Depend on Figure 2 and 3 As shown in the diagram, the transmission component of the receiver preferably has an absorber space 28 in the flow direction before the absorber 27 and another absorber space (here configured as a gathering space 33) in the flow direction after the absorber 27.

[0047] Those skilled in the art determine the operating parameters in specific circumstances, typically from the desired or required exit temperature T. out and the entry temperature T obtained by using heat from the receiver in Departure. Furthermore, those skilled in the art select a suitable gas or gas mixture for infrared absorption in the specific situation and determine the flow velocity in the absorber space 28 (the flow velocity can in turn be related to the current solar incidence). Such and other operating parameters obtained in the specific situation can be correlated with each other, with the following results: Figure 3 In section H, that is, in the absorber space 28, the increase in temperature from T2 to T3 achieved by absorption will result in a larger or smaller result depending on the specific circumstances.

[0048] The applicant has discovered that the advantages of the invention are relevantly at a ratio ≥0.3 χ, wherein, , That is, the ratio given between the heating of the heat-transferring gas achieved by absorption and its total heating achieved by absorption and convection is given when the gas flows toward the absorber 27, which radiates in the infrared range, and then flows through the absorber (or along the absorber to the outlet), that is, through the absorber. By operating appropriately with selected operating parameters, in other words by proper construction of the control device of the receiver 25, those skilled in the art can achieve the value χ ≥ 0.3 according to the invention in specific cases.

[0049] Those skilled in the art can, as mentioned, associate the ratio χ ≥ 0.3 with radiation 3 only to the absorber in specific situations. 2, 55 absorption or association with the propagation through the absorber spaces 28, 57 ( Figure 2 and 4 The absorption of solar radiation, including the infrared portion of the radiation absorbed by the absorber.

[0050] It is found that, according to the present invention, the gas that acts as an absorber in the infrared band is provided as the heat transfer medium. Furthermore, according to the present invention, the absorber space acting in conjunction with the absorber is sized such that the temperature increase (T3-T2) achieved by the heat-transferring gas that acts as an absorber in the infrared band during operation in the absorption chamber by absorption, relative to the total temperature increase (T4-T2) achieved through absorption and convection at the absorber, is χ ≥ 0.3.

[0051] Preferably, the gas that performs the heat exchange function flows toward the absorber (absorber 27) through the absorption zone (absorber space 28), wherein the gas absorbs heat in the absorption zone and also convectively heats heat through the absorber. The receiver can be constructed in multiple stages, that is, heating the heat transfer medium stage by stage. According to the invention, at least one stage is constructed for heating at a ratio of ≥0.3 χ absorbing / convective.

[0052] Preferably, the heating zone has two absorber spaces, wherein the ratio χ is set in conjunction with the absorbers for one or both absorber spaces.

[0053] Contributing equally to the high efficiency of the receiver according to the invention is that the heat radiated by the absorber is absorbed as much as possible by the heat-transferring gas within the absorber space (and, for example, does not penetrate the gas, and escapes from the receiver again as re-radiation through the opening for the solar radiation). The decisive parameter here is the absorptivity α of the heat-transferring gas, which is measured experimentally, calculated from spectral line values ​​in a molecular spectroscopy database (e.g., HITEMP2010), or can be approximately determined from emissivity charts according to Hottel's law. If, in one embodiment, the receiver, under current operating conditions, has such a distance H between the absorber and the opening that 60% or more of the heat power radiated by the absorber is absorbed by the heat-transferring gas in the space region, then a receiver designed for the absorption of absorber heat has achieved good efficiency. Particularly preferably, the height in the aforementioned space region is such that 80% or more, particularly preferably 90% or more, of the heat power radiated by the absorber is absorbed by the heat-transferring gas.

[0054] It should be noted here that the absorber space undoubtedly has an opening for solar radiation and an absorber that acts on the absorber space via its blackbody radiation, wherein, according to Figures 2 to 4 The absorber is preferably opposite the opening. However, in principle, the absorber space can also be constructed arbitrarily, not in a columnar shape, for example, with recessed sidewalls, so that the opening is smaller than the absorber surface, which is advantageous for undesirable re-radiation. In such a case, the radiation is concentrated in the opening by a concentrator and then diverged after the opening, so that the entire and larger absorber surface is irradiated. Then, the absorber space may not be below the recessed walls, but has a height below the opening such that the aforementioned degree of absorption exists in the spatial region in question (where the height exists).

[0055] Since the absorbency is related to the type of gas, its pressure, and the temperature of the absorber surface that radiates the gas and the temperature of the gas itself (Hottel's Law), those skilled in the art can determine the height based on the parameters that determine absorption: as mentioned, these are the type of gas, its operating pressure, its temperature, and the operating temperature of the absorber surface, which in this respect determine the operating state of the receiver.

[0056] A preferred embodiment of the receiver according to the invention is derived, wherein the absorber space has such a height above the absorber that, in the operating state of the receiver, 60% or more, preferably 80% or more, completely particularly preferably 90% or more of the radiated thermal power of the absorber in the space region is absorbed by the heat-transmitting gas.

[0057] Figure 5 Another embodiment of the receiver according to the invention is shown. A cross-section through the receiver 50 is shown, the receiver corresponding to... Figure 2 The receiver 25, however, has an absorber 51 with an absorbing surface 51' facing the optical opening 3 having a preferably plate-shaped section 54 extending into the absorber space 57. This section extends towards the opening 3 from the center of the absorber space 57 and is substantially parallel to the flow direction of the heat-exchanging gas, which absorbs infrared radiation, as indicated by the drawn arrow. The section 54 substantially absorbs the infrared radiation emitted by the absorbing surface 51', provided that the infrared radiation is not absorbed by the gas flowing along the section, i.e., especially in a frequency band where the gas is not heavily absorbed. Thus, the section heats up and also constitutes a blackbody radiating assembly that radiates across the overall spectrum corresponding to the temperature of the section 54 and heats itself by absorption of the heat-transferring gas flowing alongside it. The frequency of the radiation 55 is utilized in an improved manner, as the radiation at that frequency is not absorbed by the gas as the frequency causes heat to penetrate into the segment 54, which then radiates itself at all (infrared) frequencies. The segment 54 is a secondary absorber.

[0058] Such a component can be implemented on a larger scale, for example, with a diameter of 15.96 m for the absorber surface 51' and a length of 15.96 m for the absorber space 53 (from the absorber surface 51' to the optical opening 3). The receiver 50 is suitable for the flow of a large number (or all) of heliostats in an absorber tower power plant. Consequently, the receiver 50 has an absorber space 57 and the absorber 51 extends into the space as a segment or secondary absorber 54, the space preferably being constructed in a plate shape.

[0059] In another embodiment, not shown in the figure, a transparent glass wall (borosilicate glass) can be provided as a secondary absorber for the visible spectrum of sunlight, the glass wall being approximately located at the absorber surface 51' and the optical opening 3 ( Figure 4The glass wall is arranged parallel to the absorber surface 51' and has a through-hole for the gas used to transfer heat, for example, in the form of a perforated plate. The glass wall is heated by infrared radiation from the absorber surface 51' or by the frequency fraction of the infrared radiation that is not absorbed by the gas, and itself radiates in two directions as a blackbody, i.e., not only toward the optical opening but also toward the absorber. Those skilled in the art can design the glass plate in a specific case such that the ratio χ is ≥0.3 for the absorber space between the glass plate and the optical opening and the section of the glass plate belonging to the absorber space, and also for the absorber space between the glass plate and the absorber together with the section of the absorber belonging to the absorber space. According to the invention, a receiver is obtained which has a secondary absorber in the absorber space before the absorber, configured as a blackbody radiation component with reduced convection, the absorber space being arranged and constructed such that the absorber space can be heated by the infrared radiation of the absorber.

[0060] Figure 6 schematically showing the passage through Figure 2A cross-section of another embodiment of the receiver type. The solar beam 4 is incident on the absorber 27 through a window made of, for example, quartz glass 3. The radiating surface 27' of the absorber heats the gas flowing through the absorber space 26, wherein the temperature of the gas increases from the window 3 up to the absorber 27. Accordingly, the gas can be taken out via openings 91 to 91''' in the cylindrical wall of the receiver 90 at predetermined temperatures below the operating temperature of the heat-transferring fluid, but wherein the mainstream of the heat-transferring fluid is only taken out of the absorber space 26 at the operating temperature in the region of the absorber. Arrows indicate the flow direction of the heat-transferring gas, wherein the arrows are drawn longer in the openings 91 to 91''' corresponding to the gradually increasing temperature. Alternatively, or together with the openings 91 to 91''', a line 93 for the gas can be provided extending into the absorber space 26, which feeds the gas through openings 92 to 92''' at the temperature present at the locations of openings 92 to 92'''. This is particularly advantageous when heat is supplied to a subsequent process at a different temperature level via the receiver 90. The process can then guide the heat-transferring gas back to the receiver at the same different temperature, thus further preferably, an additional inlet line for the heat-transferring gas is provided in the region of openings 91 to 91''' and 92 to 92''' for introducing the gas into the absorber space 26 of the receiver 90 (this additional inlet line is omitted here for the sake of simplicity in the figures).

[0061] A receiver is obtained in which the transmission component has one or more lines 91 to 9''' and 92 to 92''' connected to the absorber space 26 for transmitting heated gas, the lines being arranged such that partially heated gas can be extracted from the absorber space 26 and / or partially heated gas can be supplied at locations where the temperature of the gas in the absorber space 26 substantially corresponds to the temperature of the supplied partially heated gas.

[0062] Such inlet and outlet lines for partially heated gas can be located at the absorption receiver according to the invention without modifying its layout, especially the layout of the absorber 27. The lines can also be used or deactivated without structural modifications due to different heat conversions.

[0063] The applicant has found that a temperature ratio χ ≥ 0.5 is particularly advantageous when used with partially heated gases, for example, when the inlet temperature T... in 1000K and outlet temperature T outWhen the partially heated gas is in the range of 1400K (i.e., at half the temperature difference) at 1800K: the temperature layer T=1400K is still within the range of pure absorption in the absorber space 26 and can be easily reached accordingly. Figure 5 This is achieved through the openings 91 to 91'' or 92 to 92''.

[0064] Figure 7a and 7b And 8a and 8b show, according to the applicant's Figure 2 The mathematical modeling of receiver 25 is based on Figure 2 Different operating parameters in the receiver. The system is modeled using the most accurate method available today, namely "Spectral line-by-line (LBL) photon Monte Carlo ray tracing", where the absorption coefficients are derived from the HITEMP2010 spectroscopy database. A receiver is modeled with an absorber space having a diameter of 15.96 m and a height of 15.96 m, and the opening 3 having a diameter of 11.28 m. This results in a 200 m... 2 The surface area of ​​the 27' that acts as an absorber and 100m² 2 The area of ​​opening 3. Water vapor is used as the heat transfer medium at a pressure of 1 bar, and there is no window in opening 3. The radiative flux at opening 3 is 200 kW / m². 2 Furthermore, the radiative flux at the surface 27' that acts as the absorber is 600 kW / m². 2 (The absorbing surface has twice the area relative to the opening 3). The absorbing surface 27' is adopted as a blackbody for radiation, and (with) Figure 2 Conversely, it has a coherent, planar, and smooth surface, so that the heat-transferring medium can be used according to... Figure 5 The type is drawn laterally from the absorber space 26 through the opening 91''' at the height of the absorber 27.

[0065] Figure 7a and 7b The receiver 20 is shown with the aid of Figures 60 and 65. Figure 2 The temperature trend along its longitudinal axis during operation, starting from opening 3: plot the temperature in Kelvin on the vertical axis, and the distance from opening 3 on the horizontal axis. (Figure 60) Figure 6 a) Shows the inlet temperature T with 1000K. in and an outlet temperature T of 400K out The process. (Figure 65) Figure 6 b) shows the same inlet temperature T with 1000K. in However, it has an outlet temperature of 800K. out The process.

[0066] Due to the heating effect of the walls during operation, a temperature distribution is obtained in the heat-transferring medium (here, water vapor) with an increased temperature at the edges of the absorber space 26. Consequently, the highest temperature is observed at the edges (on the walls) of a defined cross-section within the absorber space 26 (temperature curve 61 or 66), and the lowest temperature is observed in the middle, i.e., at the axial position of the columnar absorber space 26 (temperature curve 62 or 67). Temperature curve 63 or 68 shows the average temperature of the water vapor in the corresponding cross-section of the absorber space 26.

[0067] Besides being used according to Figure 2 and 3 In addition to the proof-of-concept of the absorptive receiver, Figure 7a and 7b The basis for this receiver is also shown. Figure 6 A feasible implementation plan.

[0068] Figure 8a This shows the receiver 20 ( Figure 2 Chart 70 shows the efficiency of the outlet temperature T. The outlet temperature T is plotted on the horizontal axis. out Among them, a constant inlet temperature T of 1000K is adopted. in Curve 71 shows the relationship between the receiver 20 and the outlet temperature T. out The relevant efficiency. For moving towards higher temperatures T out The explanation for the reduced efficiency is the increased (loss) re-radiation from the opening 3 due to the higher temperature (despite the constant inlet temperature T of 1000K). in This is because a certain share of reradiation originates from the interior (with increased temperature) of the absorber space. The conceptual design of the absorptive receiver thus possesses performance comparable to, or increasing with the outlet temperature T, of conventional, convective receivers. out Increase or even improve efficiency.

[0069] Figure 8b The diagram shows the relationship between the absorption surface 27' and the outlet temperature T. outThe relevant temperature is shown in Figure 75. A temperature distribution also exists, exhibiting higher temperatures at the edges and minimum temperatures at the axial position of the columnar absorber space 26: Curve 76 shows the temperature at the edge of the absorbing surface 27', and curve 77 shows the temperature in the middle of the absorbing surface. Curve 78 shows the average temperature of the absorbing surface. With T... out The increasingly smaller temperature difference with respect to the absorbing surface 27' can be explained by the following: the energy emission of the blackbody increases with its temperature to the fourth power, and with a relatively small temperature increase (300K here), the heat-transferring medium is violently heated even more (1000K here). Therefore, the conceptual design of the absorptive receiver is related to the set temperature T. out It exhibits remarkable flexibility: absorbers suitable for high temperatures can also be adapted to different temperatures T. out This is not the case in existing convection absorbers and supports the conceptual design of a low-cost, high-temperature absorbent receiver.

[0070] exist Figure 8a , 6 The situations shown in b and 8a, 7b also apply to receivers 20 with smaller dimensions, depending on the modeling used. Figure 2 However, the pressure in the medium through which the heat is transferred increases.

[0071] Figure 8c This shows the receiver 20 ( Figure 2 The efficiency of the graph 80 is shown, but with a window in the opening 3 and for different sizes. It can be seen that the efficiency is based on the... Figure 6 The efficiency of the large-sized receiver 20 described in a, 6b and 7a, 7b is shown in curve 82. Furthermore, the efficiency for a smaller size can be seen (the diameter and height of the absorber space 26 = 1.596 m, and the diameter of the window in the opening 3 = 1.128 m, equivalent to 1 m). 2 ), wherein the pressure in the heat-transferring gas is 10 bar, see curve 81. For relative to Figure 7a The slightly lower efficiency is explained by the fact that the flux reduction at the absorbing surface due to the window is 554.4 kW / m². 2 Instead of 600kW / m 2 .

[0072] according to Figure 8a The chart to c also applies to... Figure 3 The receiver.

[0073] exist Figure 3The diagram shows a receiver 100 with a vertically arranged axis 103, wherein the radiation from the heliostat field is directed vertically downwards by a reflector arranged in the solar tower onto the receiver 100 located near the ground. This arrangement is known to those skilled in the art as "downward radiation" (conversely, the radiation from the heliostat field can also be directed vertically upwards by a reflector or by the heliostat itself, wherein the receiver 100 is located above the solar tower). As described above, according to... Figure 2 In the opposite implementation, the heat transfer medium is now not connected to a pipe or opening in the plane of the opening (or window) 3 for solar radiation 4, but is instead transferred to the absorber space 28 in the direction of the incident radiation 4 after the opening 3. This allows the corresponding inlet line 102 for the heat transfer medium to be arranged away from the opening 3 and simultaneously protected simply. Especially in cases where the heliostat is not properly aligned, it could adversely jeopardize the [further details needed]. Figure 2 The pipe or transmission part for transferring heat is located near the opening 3 and must be constructed at high temperatures for high energy input, which is contrary to the simplicity of the receiver according to the invention in terms of structural cost.

[0074] Furthermore, especially in the vertically downward-oriented receiver 100, the fluid flow transmitted through the absorber space 28 is constructed to be quite uniform, thereby creating a distinct temperature layer at the height of the absorber space 28. In the case of a "downward radiation" arrangement, this, in particular, not only ensures a sufficiently high flow velocity of the heat-transmitting fluid toward the absorber, can also contribute to... Figures 9 to 12 A vortex is created in the fluid.

[0075] As described above, in solar tower power plants, for example, the following construction method is adopted: the receiver is arranged on the top of the tower and tilted downwards so as to directly receive the radiation from the heliostat field. The tilted orientation creates correspondingly tilted temperature layers, which can generate convective flow in the heat-transferring fluid. This convective flow disturbs the temperature layers and thus also disturbs the desired uniform temperature in the region of the absorber 27.

[0076] According to the present invention, therefore according to Figure 9 The implementation is configured such that the heat-transmitting fluid is transmitted tangentially to the transmission direction generated in the absorber space 28, thereby causing the gas guided toward the absorber 27 in the heating region or in the absorber space 28 along the transmission direction to additionally rotate around an axis 103 parallel to the transmission direction.

[0077] Figure 9A schematic view of the inclined receiver 110 is shown on one side of its opening 3 for solar radiation. Introductory lines 104 for the heat transfer medium, arranged tangentially to axis 103, are visible. These introductory lines cause the medium to rotate, or vortices to form in the medium flowing toward the absorber 27. The absorber 27 is visible in the figure through the opening or quartz window 3. For simplicity, the flow path of the medium through the absorber (or past it) is not drawn, but only the outlet nozzle 106 is shown as a dashed line, from which the medium exits the receiver 110. The outlet nozzle is preferably slightly offset upwards, which, combined with the vortices of the flowing medium, creates a stable temperature in the heat transfer medium at the outlet nozzle 106.

[0078] As a result, the transmission component is preferably configured such that, during operation, the medium transmitting heat has at least partially a vortex around an axis 127 parallel to the transmission direction of the absorber space as it passes through the absorber space along the transmission direction, wherein the transmission component has inlet openings for the medium preferably disposed in the absorber space, these inlet openings being tangentially oriented with respect to the axis of the absorber space in the same vortex direction.

[0079] It should be noted that the rotation or vortex of the flow can also be generated in the absorber space 28 by guiding the plate, since the temperature layer is preferably implemented in its cold region, and thus only does not significantly increase the cost of the receiver according to the invention.

[0080] Figures 10 to 12 Details of the receiver 120, constructed for high efficiency even in tilted or horizontal positioning, are shown. Figure 10 An external view of receiver 120 is shown. Figure 11a Figures b and c show a cross-sectional view of the receiver. Figure 12 The temperature distribution in the layers of its absorber space 28 is shown in the applicant's simulation. For the sake of simplicity in the figures, the insulation of the receiver 120 and its supporting external structure are also omitted, as such a structure would be readily conceived by those skilled in the art in the specific context.

[0081] Figure 10 The receiver 120 is shown, with its absorber space 28, collection space 33 and outlet pipe 121 (see also the diagram). Figure 2 (View). Also visible is the cold (T) in The heat transfer fluid inlet assembly 122 is a transfer assembly 29 ( Figure 2The inlet assembly 122 is a component of the receiver 120. The inlet assembly 122 has an annular space 123 into which an inlet line 124 for transferring heat fluid enters (see arrow 125). Fluid flowing into the receiver 120 through the annular space 123 passes through the absorber space 28 in a main flow direction parallel to axis 127, and becomes heated in this case, ultimately reaching a temperature T via the collection space 33 and outlet nozzle 121. out It then leaves receiver 120 (arrow 126). Solar radiation 4 enters absorber space 28 through the opening covered by annular space 123 in this figure or through window 3, until it reaches the inner side of collection space 33, the inner wall of which, in the illustrated embodiment, is constructed as an absorber for solar radiation. Figure 9 The description mentions that, in the embodiment shown, the outlet pipe 121 is also arranged at an upward offset.

[0082] Figure 11a The annular space 123 is shown in cross-section, wherein the cutting plane also extends longitudinally through the axial direction 127 of the absorber space 28 and through the inlet line 124 (see also...). Figure 10 The annular space 123 is shown to scale here, as is the adjacent area of ​​the absorber space 28 and the location of the opening 3 or window 3 for solar radiation. However, as mentioned above, the insulation and supporting structure are omitted, especially the insulation and supporting structure for the window 3 and the annular space 123. The inlet line 124 for the fluid used to transfer heat is also shown on the upstream or inlet side. On the downstream or outlet side, the annular space 123 is divided into an outer annular channel 132 with an annular outlet slit 130 and an inner annular channel 133 with an annular outlet slit 131. The outer channel 132 extends coaxially with the axis 127 of the absorber space 28 and adjacent to its wall 138, while the inner channel 133 has a frustoconical configuration and is inclined toward the interior of the absorber space 28. Thus, in the region of wall 138, some areas of reduced flow toward the absorber are formed only to a reduced or no longer critical degree, where, despite the slightly warmer walls (see the diagrams in Figures 7 and 8), a uniform temperature layer is eventually generated along the cross-section of the absorber space 28 before the absorber (see also...). Figure 12 Therefore, it is particularly preferred that the flow component from the outer channel 132 extends parallel to the wall 138, and its angle relative to the wall is preferably less than or equal to 5 degrees. A positive effect can always be achieved when the angle is less than or equal to 10 degrees or 15 degrees.

[0083] Circular channels 132 and 133 are equipped with guide plates 134 and 135 (see...) Figure 11bThis creates openings in the outlet gaps 130 and 131 for the medium to transfer heat, and additionally imparts a tangential flow component to the medium relative to axis 127. Consequently, the medium enters the absorber space 28 in a directional flow, and in addition to the main flow direction parallel to axis 127, it also has a (vortex) flow direction tangential to axis 127. This produces the spiral flow lines 136 and 137 exemplarily drawn in the figure. As a result, interference with the temperature layer in receiver 120, especially in inclined or horizontal orientations, such as due to temperature-induced convection flow, can be suppressed.

[0084] Figure 11b Show Figure 11a The enlarged section is used to illustrate the situation. In particular, the components of the guide plate 134' or 134'''' and the directional flow 136 can be seen, namely the component in the direction of the main flow 141 and the tangential component 142.

[0085] A receiver is obtained in which the transmission component has openings for the medium for heat transfer into the absorber space. These openings are arranged adjacent to the wall 138 of the absorber space 28 and generate a flow component of fluid flowing into the absorber space 28 in the main flow direction, the slope of which relative to the wall 138 is less than 15 degrees, preferably equal to or less than 5 degrees. According to the applicant, such a small angle is necessary to avoid areas in the wall 138 where the flow velocity decreases towards the absorber, which is critical to the efficiency of the absorber space.

[0086] Furthermore, a receiver is obtained in which the transmission component has openings in the absorber space for the transmission of heat, which generate a flow component of the fluid flowing into the absorber space 28 tangentially relative to the axis 127 of the absorber space 28.

[0087] Finally, a method for operating the receiver is obtained, wherein the gas that performs infrared absorption is rotated in the absorber space (28, 53) of the heated region (26), so that the gas has vortices in the absorber space about an axis (127) extending along the transmission direction or the main flow direction.

[0088] Figure 12 Show according to The applicant's CFD simulation The temperature distribution in the absorber space 28 of the receiver 120 has the following boundary conditions: ▪ The diameter of the absorber space is 0.8m, and the pressure in the absorber space is 1 bar; ▪ T in =800ºK, mass flow rate of the heat-transferring fluid = 0.045kg / s; ▪ Solar radiation power passing through transparent opening 3 = 250kW, opening diameter: 0.6m; ▪ Fluid that transfers heat: water vapor; ▪ Water vapor spectral radiative properties modeled using the grey gas weighted summation (WSGG) model and radiative properties solved using the discrete coordinate (DO) method; ▪ Black Wall, ε wall =1; ▪ Gravity acts vertically downwards (towards the horizontal receiver); ▪ Angle of fluid flowing into the absorber space: 45 degrees.

[0089] The angle of the inflow fluid in the annular channel 132 is directional flow 136 and Figure 11b The angle between the main flow direction 141 and the direction of flow. As described above, the annular channel 133 has a frustoconical configuration, that is, its downstream end is rounded. The angle at which the fluid flows into the absorber space from this annular channel is similar to the angle of its flow direction relative to the tangent on the circle.

[0090] Here, for simulation purposes, a simplified geometry is assumed in this region between the optical opening 3 and the wall 138 of the absorber space 28: the intermediate space between the exit slits 130 and 131 ( Figure 11a b) is replaced by a truncated cone-shaped wall region 150.

[0091] The simulation produces an outlet temperature T of 1862ºK. out And the temperature layers shown in the figure, represented by temperature curves 140 to 145. Temperature curve 140 corresponds to a temperature of 1420ºK, curve 141 corresponds to a temperature of 1533ºK, curve 142 corresponds to a temperature of 1589ºK, curve 143 corresponds to a temperature of 1645ºK, curve 144 corresponds to a temperature of 1702ºK, and curve 145 corresponds to a temperature of 1870ºK.

[0092] It has been shown that, despite the complex thermodynamic conditions caused, particularly by the heat of the hot wall 138 heated by the radiation of absorber 27, and the complex flow conditions caused, particularly by the convection generated by temperature differences and gradients, a temperature layer exists in which the temperature continuously increases from opening 3 to outlet nozzle 121. As a result, reflections of reduced efficiency through opening 3 can be reduced. It has also been explained that those skilled in the art can appropriately determine the inflow direction, vortex, or rotation about an axis extending through the absorber space of the fluid in particular, and similarly determine the location of the outlet nozzle (according to...). Figure 2 and 3 To 6 in the middle, or according to Figure 9 and 10Offset). If, for example, optimal vortices can be generated under other parameters (such as those in the simulation above), then the outlet nozzle can also be positioned centrally in a horizontal orientation. Conversely, a combination of weaker or less-than-optimal vortices with an offset position of the outlet nozzle can produce the desired temperature layer.

[0093] Therefore, according to the applicant's understanding, the size of receiver 20 and the size of the absorption receiver according to all embodiments of the invention can be easily adjusted, wherein, for similar high efficiency or similar temperature conditions, the pressure must increase proportionally when the size is reduced, for example, when the size is reduced by a factor of ten, the pressure decreases by a factor of ten. However, as the pressure in the gas transferring heat increases, the efficiency tends to increase slightly out of proportion. Figure 7c shows the case for a pressure of 10 bar. In specific cases, those skilled in the art can set an overpressure between 2 and 20 bar, particularly preferably between 5 and 15 bar, and entirely and particularly preferably—as stated above—10 bar.

[0094] According to Figures 3 to 10 In the simulation implementation, χ is in the range >0.9 because convection is minimal on the planar and smooth absorption surface. It should be noted that convection, in principle, slightly cools the absorber, thus reducing the efficiency loss caused by reflections from opening 3, i.e., improving the receiver efficiency. However, enhanced convection leads to increased pressure loss in the flowing gas (which again reduces efficiency) and increases the construction cost of the absorber. In specific cases, those skilled in the art can determine the optimal ratio between absorption and convection, i.e., within the range of χ ≥ 0.3. A certain value (see) Figure 4 (Explanation).

[0095] According to the applicant's understanding, as stated, a value of χ=0.3 already results in a simple design for the receiver of the present invention, and the efficiency is equal to (or higher than) that of known receivers designed according to the convection principle.

[0096] Because the high temperature of the absorber is advantageous for the strongest possible blackbody radiation entering the absorber space, but also for the sidewalls of the absorber space, all kinds of coolant, especially cooling channels—as provided in receivers according to the prior art—are eliminated—either cooling channels in the walls or cooling channels in the absorber to ensure convection. A receiver is thus obtained in which the absorber space and / or the walls of the absorber have no coolant, especially no cooling channels. This, of course, does not include coolant for special operating conditions of the receiver, such as emergency cooling systems in fault conditions that are inherently inconsistent with specified operation. Therefore, a receiver is obtained in which the absorber space and / or the walls of the absorber have no coolant for specified operation.

[0097] In another embodiment not shown in the figures, the absorber and the receiver 25 ( Figure 2 The absorber space 28 is arranged in the same manner relative to the optical opening 3 and forms the wall region of the absorber space 28. Figure 2 However, unlike the receiver 25, the absorber does not have a flow opening for the heat transfer medium, but is at least partially gas-tight for the heat transfer medium, so that the heated gas flows radially out of the absorber space at the height of the absorber. This further simplifies the structure of the absorber, and the ratio χ can be increased to a value higher than 0.3.

[0098] Those skilled in the art can optimize based on Figure 2 The implementation form, or by combining the implementation form with other described features (according to Figure 4 The additional section 54 of the absorber 51, according to an embodiment (such as a glass plate not shown in the figure), is combined to increase the value of the ratio χ from ≥0.3 to ≥0.4 or ≥0.5 or ≥0.6 or ≥0.7 or even to ≥0.8.

[0099] Figure 13 The steps of a method for operating a preferred spatial receiver according to the invention are shown. In the first step 80, a suitable receiver is selected, for example, one equipped with a preferred spatial receiver according to the invention. Figure 2 The receiver has a structure that includes an absorber that can be heated by sunlight. A gaseous heat transfer medium is guided toward the absorber by a transmission device so as to heat the medium through the absorber for heat transfer.

[0100] In the second step 81, a gas that acts as an absorber in the infrared range, especially anisotropic gases or one of the following gases: CO2, water vapor, CH4, NH3, CO, SO2, SO3, HCl, NO, and NO2 (or a mixture of the gases) is selected as the heat transfer gas so that the blackbody radiation of the absorber is absorbed before the absorber is reached by the absorption of the gas directed toward the absorber, thereby heating the heat transfer medium.

[0101] In the third step 82, the operating parameters of the receiver are adjusted such that, during the operation of the receiver, the ratio χ of the temperature rise of the heat-transmitting medium caused by absorption before the absorber to the temperature rise achieved by absorption and convection at the absorber is ≥0.3.

[0102] In the fourth step 83, the receiver is put into operation and operated with parameter χ≥0.3.

[0103] A method is provided for operating a receiver having a heating region for heating a heat-transferring medium and a transmission assembly for transmitting the medium through the heating region. The heating region includes an opening for solar radiation and an absorber arranged in the path of the incident solar radiation. A gas that absorbs radiation in the infrared band is used as the heat-transferring medium. This gas is transmitted to the heating region at one end with the opening, guided through the heating region toward the other end with the absorber in the same direction as the solar radiation incident via the opening, and then discharged from the heating region. The operating parameters of the receiver are adjusted and the gas is selected such that the temperature of the gas increases during transmission through the heating region (towards the absorber) by absorbing radiation, such that the ratio χ of the temperature increase (T3-T2) achieved by absorbing radiation to the total temperature increase (T4-T2) achieved by absorption and convection at the absorber is ≥0.3.

[0104] In one embodiment, the ratio χ ≥ 0.3 is associated with the absorption of radiation from the absorber only, such that the temperature increases during transmission through the heating region by absorbing the radiation from the absorber, such that the temperature increase (T3-T2) achieved by absorbing the radiation from the absorber is ≥ 0.3 relative to the total temperature increase (T4-T2) achieved by absorbing the radiation from the absorber and convection at the absorber.

[0105] Those skilled in the art can, in specific cases, associate the ratio χ ≥ 0.3 with absorption only of the absorber radiation 32, 55 or with absorption including absorption of radiation propagating through the absorber spaces 28, 57. Figure 2 and 4 The absorption of solar radiation, including the infrared portion of the radiation absorbed by the absorber.

[0106] Preferably, an anisotropic gas, more preferably CO2, water vapor, CH4, or a mixture of said gases is selected as the gas for absorption.

[0107] Those skilled in the art can then modify the method according to the invention such that the ratio χ is equal to or greater than 0.4, or 0.5, or preferably equal to or greater than 0.7, particularly preferably equal to or greater than 0.8.

[0108] In one embodiment, the method according to the invention can be configured such that the gas is guided through the absorber. Alternatively, the gas can be guided sideways through the absorber.

[0109] Figure 14 The invention illustrates a receiver, for example, according to Figures 2 to 4 The method for manufacturing a receiver includes the following steps: In step 87, the absorber is configured as a blackbody radiation component with reduced convection, and an absorber space is correspondingly provided to interact with the absorber so that heat can be transferred to the heat-transferring gas. Following this, in step 88, the gas that absorbs in the infrared band is arranged as the heat-transferring gas along with the size of the absorber space such that a predetermined operating state of the receiver can be defined, in which the temperature increase of the heat-transferring gas achieved by absorption of the blackbody (infrared) radiation and the infrared fraction of the sun by the absorber is in a ratio ≥0.3χ relative to the temperature increase achieved by absorption and convection at the absorber.

[0110] A method for manufacturing a receiver is provided, the receiver having a heating region for heating a heat-transferring medium and a transmission component for transmitting the medium through the heating region, wherein an optical opening for sunlight and an absorber for absorbing sunlight are provided in the heating region, characterized in that the absorber is constructed as a blackbody radiation component with reduced convection, and an absorber space is provided that interacts with the absorber, wherein a gas acting as an absorptive medium in the infrared band is configured as the heat-transferring medium and the absorber space is sized such that, in a predetermined operating state of the receiver, the temperature of the heat-transferring medium movably flowing through the absorber space increases by absorbing infrared radiation from the absorber (and the infrared fraction of solar radiation), such that the ratio χ of the temperature increase (T3-T2) achieved by absorption in the absorber space to the total temperature increase (T4-T2) achieved by absorption and convection at the absorber is ≥0.3.

[0111] Preferably, the gas is an anisotropic gas, particularly preferably CO2, water vapor, CH4, NH3, CO, SO2, SO3, HCl, NO and NO2, or a mixture of these gases.

[0112] Furthermore, in one embodiment of the invention, the ratio χ is adjusted to be equal to or greater than 0.4, preferably 0.5, particularly preferably 0.6, completely preferably 0.7, and most preferably 0.8.

[0113] Finally, in another embodiment, a secondary absorber configured with a blackbody radiation component for reduced convection can be disposed in the absorber space, and more preferably the receiver is designed as a spatial receiver.

Claims

1. A method for operating a receiver (25, 50, 100, 120), the receiver having a heating region (26) for heating a heat-transferring medium and a transmission component (29) for transferring the medium through the heating region (26), wherein, In the heating region (26), an opening (3) for solar radiation (4) and an absorber (27) for absorbing solar radiation are provided in the transmission path of the medium. The heating region (26) is characterized by having a gas that absorbs solar radiation in the infrared range as the medium for heat transfer. This gas is transmitted to the heating region (26) after the opening (3) along its flow direction. Furthermore, in this heating region, the solar radiation (4) is absorbed in the same direction as the solar radiation (4) that is incident through the opening (3) and directly onto the absorbers (27, 51). One end of the opening (3) is guided toward the other end, which is opposite the opening (3) and has the absorbers (27, 51), and is discharged from the heating zone (26) there. The operating parameters of the receivers (25, 50, 100, 120) are adjusted and the gas is selected such that its temperature increases during transmission through the heating zone (26) due to the absorption of radiation (4) such that the temperature increase (T3-T2) due to the absorption of radiation (4) is proportional to the total temperature increase (T4-T2) due to absorption and convection at the absorbers (27, 51) by χ ≥ 0.

5.

2. The method according to claim 1, wherein, The temperature increases during transmission through the heating zone (26) due to the absorption of radiation from the absorber (27), such that the increase in temperature (T3-T2) due to the absorption of radiation from the absorber (27) is proportional to the total increase in temperature (T4-T2) due to the absorption of radiation from the absorber and convection at the absorbers (27, 51) χ≥0.

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3. The method according to claim 1, wherein, The heating area has an absorber space (28) arranged in the path of the incident solar radiation (4) and disposed between the opening (3) and the absorber (27, 51), wherein the ratio χ is the ratio of the temperature increase (T3-T2) in the absorber space due to the absorption of radiation from the absorber (27) to the total temperature increase (T4-T2) due to absorption and convection at the absorber (27) after the gas has passed through the absorber.

4. The method according to claim 1, wherein, The heating area (26) has two absorber spaces (28) with a common absorber (27, 51), wherein the ratio χ is set for one or both of the absorber spaces.

5. The method according to claim 1, wherein, The gas is an anisotropic gas.

6. The method according to claim 5, wherein, The gas is one of CO2, water vapor, CH4, NH3, CO, SO2, SO3, HCl, NO, and NO2, or a mixture thereof.

7. The method according to claim 6, wherein, The gas is a mixture containing water vapor and CO2.

8. The method according to claim 1, wherein, The ratio χ is equal to or greater than 0.

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9. The method according to claim 8, wherein, The ratio χ is equal to or greater than 0.

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10. The method according to claim 9, wherein, The ratio χ is equal to or greater than 0.

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11. The method according to claim 1, wherein, This allows the gas to be guided through the absorber (27, 51).

12. The method according to claim 1, wherein, This allows the gas to be guided from the side through the absorbers (27, 51).

13. The method according to claim 1, wherein, This causes the gas to be under overpressure in the heating zone (26) in the range of 2 to 20 bar.

14. The method according to claim 13, wherein, This causes the gas to be under overpressure in the heating zone (26) in the range of 5 to 15 bar.

15. The method according to claim 14, wherein, This causes the gas to be under an overpressure of 10 bar in the heating zone (26).

16. The method according to claim 1, wherein, The gas is guided around the absorber (27, 51) to the back side of the absorber (27, 51) and then guided away from the absorber.

17. The method according to claim 1, wherein, The gas that has become heated by absorbing radiation from the absorbers (27, 51) is removed from the absorber space once the gas has become partially heated and / or the partially heated gas is transferred to the absorber space, wherein the transfer in the absorber space occurs at a location where the temperature in the absorber space substantially corresponds to the temperature of the partially heated gas.

18. The method according to claim 1, wherein, The gas that performs infrared absorption is transmitted tangentially to the heating region (26) along the transmission direction, such that the gas guided toward the absorber (27, 51) in the transmission region along the transmission direction additionally rotates about an axis (127) parallel to the transmission direction.

19. The method according to claim 1, wherein, The gas that performs infrared absorption is placed in the absorber space of the heating zone (26) in such a rotating manner that the gas has a vortex in the absorber space around an axis (127) parallel to the transmission direction.

20. A method of manufacturing a receiver (25, 50, 100, 120), the receiver having a heating region for heating a heat-transferring medium and a transmission assembly (29) for transferring the medium through the heating region, wherein, An optical opening (3) for sunlight and absorbers (27, 51) arranged in the path of incident sunlight are provided in the heating region. The absorbers (27, 51) are configured as radiation components and have absorber spaces (28, 57) that cooperate with them. In these absorber spaces, the opening (3) and the absorbers (27, 51) are positioned opposite each other, defining the absorber spaces (28, 57). Gases that absorb sunlight in the infrared range, acting as a heat transfer medium, are directly incident on the heated region through the opening. The sunlight on the absorbers (27, 51) is directed in the direction of the absorbers (27, 51) and is arranged such that the absorber spaces (28, 57) are sized such that, in a predetermined operating state of the receiver, the temperature of the heat-transmitting medium that can operatively flow through the absorber spaces (28, 57) increases due to the absorption of infrared radiation from the absorbers, such that the ratio χ ≥ 0.3 of the temperature increase (T3-T2) due to absorption in the absorber spaces (28, 57) to the total temperature increase (T4-T2) due to absorption and convection at the absorbers (27, 51).

21. The method according to claim 20, wherein, An absorber space (28, 57) is arranged between the opening and the absorber (27, 51) along the path of the incident solar radiation, and the ratio χ is set as the ratio of the temperature increase (T3-T2) in the absorber space (28, 57) due to the absorption of radiation from the absorber (27, 51) to the total temperature increase (T4-T2) due to absorption and convection at the absorber after the gas has passed through the absorber.

22. The method according to claim 20, wherein, The gas is an anisotropic gas.

23. The method according to claim 22, wherein, The gas has one or more of the following: CO2, water vapor, CH4, NH3, CO, SO2, SO3, HCl, NO, and NO2.

24. The method according to claim 23, wherein, The gas has a mixture of water vapor and CO2.

25. The method according to claim 20, wherein, The ratio χ is equal to or greater than 0.

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26. The method of claim 25, wherein, The ratio χ is equal to or greater than 0.

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27. The method according to claim 26, wherein, The ratio χ is equal to or greater than 0.

6.

28. The method according to claim 27, wherein, The ratio χ is equal to or greater than 0.

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29. The method according to claim 28, wherein, The ratio χ is equal to or greater than 0.

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30. The method of claim 20, wherein, A secondary absorber (54) configured as a radiation component is provided in the absorber space (28, 57).

31. A receiver (25, 50, 100, 120) for implementing the method according to claim 1 or manufactured according to the method according to claim 20, comprising: a heating region (26) for heating a heat-transmitting medium, said heating region having an opening (3) for solar radiation (4) and an absorber (27, 51) arranged in the path of the incident solar radiation (4) for absorbing said solar radiation; a transmission assembly (29) for transmitting said medium through said heating region (26), characterized in that, An absorber space (28, 57) for heating the heat transfer medium is also provided. One end of the absorber space is formed by the opening (3) for solar radiation, and the other end is formed by the absorber (27, 51) opposite to the opening (3), such that the solar radiation (4) incident through the opening (3) directly and substantially completely strikes the absorber (27, 51), and the absorber (27, 51) is configured as a radiation component acting in the absorber space (28, 57), and the transmission component (29) is configured to transmit the gas as the heat transfer medium, and the medium is transmitted to the absorber space (28, 57) in the region of the opening (3), but in the direction of the incident radiation (4), behind the opening (3) for the solar radiation (4), and in the absorber (28, 57)... The heat transfer medium is discharged from the absorber space (28, 57) in the region of 7, 51, such that during operation, the heat transfer medium completely passes through the absorber space (28, 57) from the end with the opening (3) to the other end with the absorber (27, 51) in the direction corresponding to the incident solar radiation (4), and wherein the heat transfer medium is essentially a gas that absorbs in the infrared band, and the size of the absorber space (28, 57) that cooperates with the absorber (27, 51) is set such that during operation, the temperature increase (T3-T2) of the heat transfer gas that absorbs in the infrared band due to absorption in the absorber space (28, 57) is χ≥0.3 relative to the temperature increase (T4-T2) due to absorption and convection at the absorber (27, 51).

32. The receiver (25, 50, 100, 120) according to claim 31, wherein, The dimensions of the absorber spaces (28, 57) are set such that, during operation, the temperature increase (T3-T2) of the heat-transmitting gas that acts as an absorber in the infrared band due to the absorption of radiation from the absorbers (27, 51) in the absorber spaces (28, 57) is χ ≥ 0.3 relative to the temperature increase (T4-T2) due to the absorption of radiation from the absorbers (27, 51) and convection at the absorbers (27, 51).

33. The receiver (25, 50, 100, 120) according to claim 31, wherein, An absorber space (28, 57) is arranged between the opening (3) for the solar radiation (4) and the absorber (27, 51), wherein χ is the ratio of the temperature increase (T3-T2) in the absorber space (28, 57) due to the absorption of radiation from the absorber to the total temperature increase (T4-T2) due to absorption and convection at the absorber (27, 51) after the gas has passed through the absorber.

34. The receiver (25, 50, 100, 120) according to claim 31, wherein, The heating zone has two absorber spaces (28, 57), the absorbers (27, 51) are common to these absorber spaces, and the ratio χ is set for one or both of the absorber spaces (28, 57).

35. The receiver (25, 50, 100, 120) according to claim 34, wherein, The connecting channels guided around the absorbers (27, 51) enable the two absorber spaces (28, 57) to be interconnected.

36. The receiver (25, 50, 100, 120) according to claim 31, wherein, The absorber (27, 51) has at least a partially airtight surface (27').

37. The receiver (25, 50, 100, 120) according to claim 36, wherein, The absorbers (27, 51) are plate-shaped.

38. The receiver (25, 50, 100, 120) according to claim 31, wherein, The absorber spaces (28, 57) and / or the walls of the absorbers (27, 51) are free of coolant.

39. The receiver (25, 50, 100, 120) according to claim 31, wherein, For the receivers (25, 50, 100, 120) to operate as specified, there is no coolant in the absorber spaces (28, 57) and / or the walls of the absorbers (27, 51).

40. The receiver (25, 50, 100, 120) according to claim 31, wherein, During operation, the heat-transferring gas contains anisotropic gases.

41. The receiver (25, 50, 100, 120) according to claim 40, wherein, The gas used to transfer heat contains one or more of the following: CO2, water vapor, CH4, NH3, CO, SO2, SO3, HCl, NO, and NO2.

42. The receiver (25, 50, 100, 120) according to claim 41, wherein, The heat-transferring gas contains a mixture of water vapor and CO2.

43. The receiver (25, 50, 100, 120) according to claim 41, wherein, The secondary absorber (54) is disposed in the absorber space (28, 57) and is arranged and configured such that the secondary absorber can be heated by the infrared radiation of the absorber (27, 51) and, in operation, act on the absorber space (28, 57) by its own radiation.

44. The receiver (25, 50, 100, 120) according to claim 43, wherein, The secondary absorber is plate-shaped.

45. The receiver (25, 50, 100, 120) according to claim 43, wherein, The secondary absorber does not substantially obstruct the absorber.

46. ​​The receiver (25, 50, 100, 120) according to claim 31, wherein, The transmission assembly has one or more lines (91 to 91''', 92 to 92''') connected to the absorber spaces (28, 57) for transmitting heated gas, these lines being arranged such that partially heated gas can be extracted from the absorber spaces (28, 57) and / or partially heated gas can be transmitted to the absorber spaces at locations where the temperature of the gas in the absorber spaces (28, 57) substantially corresponds to the temperature of the partially heated, transmitted gas.

47. The receiver (25, 50, 100, 120) according to claim 31, wherein, The absorber spaces (28, 57) are designed for gas pressures in the range of 2 to 20 bar.

48. The receiver (25, 50, 100, 120) according to claim 47, wherein, The absorber spaces (28, 57) are designed for gas pressures in the range of 5 to 15 bar.

49. The receiver (25, 50, 100, 120) according to claim 48, wherein, The absorber spaces (28, 57) are designed for a gas pressure of 10 bar.

50. The receiver (25, 50, 100, 120) according to claim 31, wherein, The ratio χ is equal to or greater than 0.

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51. The receiver (25, 50, 100, 120) according to claim 50, wherein, The ratio χ is equal to or greater than 0.

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52. The receiver (25, 50, 100, 120) according to claim 51, wherein, The ratio χ is equal to or greater than 0.

8.

53. The receiver (25, 50, 100, 120) according to claim 31, wherein, The transmission component (29) is configured such that, during operation, the heat-transmitting medium has at least partially a vortex around an axis (127) parallel to the transmission direction of the absorber space (28, 57) during its passage through the absorber space (28, 57) along the transmission direction, wherein the transmission component (29) has an inlet opening for the medium disposed at the absorber space (28, 57), the inlet opening being tangentially oriented relative to the axis of the absorber space (28, 57) along the same vortex direction.

54. The receiver (25, 50, 100, 120) according to claim 31, wherein, The transmission assembly has openings for the medium used for transmitting heat into the absorber spaces (28, 57), these openings being arranged adjacent to the wall 138 of the absorber spaces (28, 57), and generating a flow component of fluid in the mainstream direction flowing into the absorber spaces (28, 57) at an inclination of less than 15 degrees relative to the wall 138.

55. The receiver (25, 50, 100, 120) according to claim 54, wherein, The slope is equal to or less than 10 degrees.

56. The receiver (25, 50, 100, 120) according to claim 55, wherein, The slope is equal to or less than 5 degrees.

57. The receiver (25, 50, 100, 120) according to claim 31, wherein, The transmission assembly has openings in the absorber spaces (28, 57) for the medium used to transmit the heat, and these openings generate flow components of the fluid flowing into the absorber spaces (28, 57) tangential to the axis 127 of the absorber spaces (28, 57).

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