PARABOLIC CONCENTRATING SOLAR COLLECTOR
Patent Information
- Application Number
- ES2025030975U
- Authority / Receiving Office
- ES · ES
- Patent Type
- Utility models
- Current Assignee / Owner
- Filing Date
- 2021-02-24
- Publication Date
- 2026-08-13
- Estimated Expiration
- 2031-02-24
Abstract
Description
PARABOLIC CONCENTRATING SOLAR COLLECTOR OBJECT OF THE INVENTION The present invention relates to a parabolic concentrating solar collector, which features a novel structure from which multiple advantages are derived. The object of the invention is to provide a self-orienting collector with a simple structure that makes it more economical, with reduced dimensions that allow a single product, by virtue of its multiplication, to adapt to very diverse required performances, easy to regulate, with high performance, with active and passive safety means, as well as with self-cleaning means. BACKGROUND OF THE INVENTION In the practical application of the invention, parabolic concentrating solar collectors are known, in which a parabolic structure participates that concentrates solar radiation onto a collector itself, in order to heat a fluid passing through it, normally water, without ruling out other fluids. To optimize the performance of these types of devices, it is essential that they include means of self-orientation, due to the changing orientation of solar radiation throughout the day. In this sense, these types of devices tilt with respect to a rotation axis located behind the parabolic surface, thus affecting the entire structure. This entails the fact that the fluid inlet and outlet pipes in the collector itself are subjected to torsional torques, making the participation of rotary connections indispensable, which are complex, expensive and difficult to thermally insulate. Another problem with these types of devices is that their configuration creates a "candle" effect, which could damage them. In this sense, the degree of mobility of these devices is relatively limited, so complete protection against strong winds cannot be guaranteed depending on their direction. Furthermore, these types of devices lose effectiveness over time due to dirt that may accumulate on their reflective concentration surface, so they are sometimes placed in locations that are difficult to access for manual cleaning. DESCRIPTION OF THE INVENTION The parabolic concentrating solar collector that is advocated fully and satisfactorily resolves the aforementioned problems, in each and every one of the aspects discussed. To this end, in accordance with one of the essential characteristics of the invention, it has been provided that the element on which the solar radiation is concentrated, in this case a vacuum tube, is arranged on a static frame that is linked to it at both ends, that is, that said vacuum tube is not at any time affected by the rotational movements of the parabolic reflecting and tilting surface. More specifically, and contrary to what happens in conventional collectors of this type, the parabolic reflective surface is designed to tilt with respect to the imaginary central and longitudinal axis of the vacuum tube. To achieve this, the parabolic reflecting surface will be linked by its curved lateral edges to a series of radial arms that converge on a bearing or bushing whose axis, as mentioned, is axial to the imaginary longitudinal and mean axis of the vacuum tube. Based on this structure, in the support frame of said vacuum tube, at whose ends the corresponding tilting axes of the parabolic reflecting surface are established, at least one small electric motor with a pinion will be arranged that will mesh with a toothed wheel attached to the supporting structure of the parabolic reflecting surface. This structure offers multiple advantages, among which the following stand out: Since the vacuum tube maintains a static, invariable position, the inlet and outlet tubes of the fluid to be heated do not require complex articulated connections and can be easily thermally insulated, which simplifies and reduces the cost of assembly. The mechanisms by which the parabolic reflector can be tilted are not limited in their range of motion, unlike in conventional collectors. This allows them to be completely inverted, both as an active safety measure against strong winds or excessive temperature inside the vacuum tube, and to carry out automatic collector cleaning, as will be discussed later. According to another feature of the invention, the vacuum tube is provided to have a novel structure, such that the chamber through which the heat transfer fluid to be heated circulates is subdivided into two concentric cylindrical chambers, an inner chamber, through which the cold fluid is intended to flow, and an outer chamber, concentric to this one, which communicates with the former from an orifice at its lower end, so that the contact surface with the radiation zone of the vacuum tube is maximized, which corresponds to the outer surface of the outer chamber, thus optimizing the performance of said tube. To further optimize this heat transfer process, it has been planned that the heat transfer fluid, as it moves through the space defined between the two chambers, will be circulated through a helical deflector, established between both chambers, which forces the heat transfer fluid to flow in a helical direction, thus achieving a much more homogeneous and optimal heat transfer. In this sense, the access section to the inner chamber must be the same as the outlet section of the heat transfer fluid from the outer chamber, in order to avoid pressure differences. The collector will be able to self-orient itself from any known self-orientation system, either in real time, based on the calculation of the angle of incidence of the sun, for which it will be assisted by one or more photovoltaic panels that ensure its total autonomy, and this movement can be simply programmed by means of a clock. In this sense, and as can be observed, throughout the present description the orientation of the collector has not been discussed, since it could be either horizontal (following the azimuth), or vertical (east-west), without this affecting the essence of the invention. According to another feature of the invention, the parabolic reflective surface is provided to include in its middle zone a series of sectors which, being also of a reflective nature, act as hinged gates against the tension of a spring, on a tilting axis, thus determining passive safety means against strong gusts of wind, which allow the folding of said sectors and the passage of air through them, reducing the resulting stresses on the collector assembly. Another novel feature of the invention is that, in the case that the collector adopts a horizontal arrangement, a series of pressurized water jet nozzles are established under the structure or support frame of the same, which allow the washing and consequent cleaning of the reflective parabolic surface, when it is turned completely over, remaining oriented downwards, in opposition to said nozzles. This cleaning process can be easily automated, as well as the self-orientation of the collector based on the position of the sun, taking advantage of the inclusion of the photovoltaic panel or panels described above. Another improvement to the invention is that, optionally, one of the device's end support frames has a scissor-type structure, adjustable by means of a worm gear connected to an electric motor linked to the device's control electronics, thus allowing the concentrator's tilt to be adjusted according to the azimuth axis. In this way, a parabolic solar concentrator adjustable to two axes is achieved. Finally, it should be noted that, since the parabolic reflecting surface only concentrates solar radiation on an arc of the circular surface of the vacuum tube, a Fresnell-type concentrating lens has been arranged over the area not affected by the concentrator, which will obviously be attached to the tilting structure associated with the parabolic reflecting surface. As previously stated, the device of the invention is designed to be manufactured preferably in small and manageable sizes, so that they can be implemented in a multiple number of devices, which in addition to providing greater adaptability to the requirements of each case, allows for better control of the temperature of the entire installation, by being able to selectively disable some devices and others to adapt to the changing requirements that the installation may have. The device described thus exhibits high performance, on the order of 95%, compared to other known systems. Similarly, it is worth highlighting the modular nature of the device of the invention, since it is a scalable device that can be grouped with others of the same type, not requiring large lengths as is the case with existing parabolic solar concentrators, which implies great versatility in assembly. DESCRIPTION OF THE DRAWINGS To complement the description that follows and to aid in a better understanding of the characteristics of the invention, according to a preferred embodiment thereof, a set of drawings is included as an integral part of said description, in which, for illustrative and non-limiting purposes, the following has been represented: Figure 1 shows a plan view of an arabolic concentrating solar collector made in accordance with the object of the present invention. Figure 2 shows a profile view of the device in the previous figure. Figure 3 shows a view similar to the previous figure, but in which the parabolic reflecting surface has changed its inclination to its safety / inoperability position, which coincides with the washing position, and it can be observed that the vacuum tube is not affected by this movement. Figure 4 shows a profile view of the device, in which it appears with its passive safety features in a working condition. Figure 5 shows a cross-sectional detail of the new internal structure planned for the vacuum tube that participates in the device of the invention. Figure 6 shows a detail of one of the device's end support frames. PREFERRED EMBODIMENT OF THE INVENTION In view of the figures described, it can be observed how the parabolic concentrating solar collector of the invention is made up of a parabolic reflection surface (1) and an element on which the solar radiation is concentrated, in this case a vacuum tube (2), with its corresponding inlet (3) of water or fluid to be heated and outlet (4) of hot fluid, with the particularity that the vacuum tube (2) is arranged on a frame (5) in a static way, that is, attached to said frame, being linked to it at both ends. For its part, and contrary to what happens with the usual parabolic concentration collectors, it has been planned that the parabolic reflection surface (1) tilts with respect to the imaginary central (6) and longitudinal axis of the vacuum tube (2). More specifically, this parabolic reflection surface (1) is linked through its lateral ends with arms (7) that converge in a bearing whose axis, as mentioned, is axial to the imaginary longitudinal and mean axis of the vacuum tube, so that in correspondence with the entrance and exit (3-4) of the vacuum tube, it has been provided that these arms are fixed to a ring (8), which is linked to the structure of the vacuum tube (2) through a bearing, a ring to which a toothed wheel (9) is fixed, in which a pinion (10) meshes, associated with a small electric motor (11), fixed to the structure associated with the vacuum tube (2). This structure allows the parabolic reflection surface (1) to rotate 360º with respect to the vacuum tube without interfering with the pipes associated with the inlet (3) and outlet (4), which allows the parabolic reflection surface (1) to be rotated to the position shown in figure 3, or any other active safety position depending on the wind direction, which will be controlled by a microprocessor and the corresponding conventional control / sensing means, and can also be used to generate shade on the vacuum tube itself, when the temperatures reached inside may be excessive. To maximize the heat transfer performance in the vacuum tube (2), it has been planned that it will have a completely novel structure, according to what is shown in figure 5, so that the chamber through which the heat transfer fluid to be heated circulates is subdivided into two concentric cylindrical chambers, an inner chamber (19), through which the cold fluid is intended to flow, open at one of its ends through which it communicates with an outer chamber (20), concentric to this, which is on which the solar radiation is concentrated in the body of the vacuum tube, with the particularity that for a better distribution of the heat transfer fluid in the body of said chamber, it has been planned that a helical deflector (21) has been provided in it which forces the heat transfer fluid to rotate on the surface of heat concentration in its movement towards the exit of said vacuum tube. In this regard, and as previously mentioned, the section of the inlet to the inner chamber (19) must be the same as the section of the outlet of the outer chamber (20) so that pressure differences are not created. Returning to Figure 3, it has been planned that the frame (5) will incorporate pressurized water jet nozzles (12), which allow the automatic washing of the parabolic reflection surface (1), either periodically and on a programmed basis, or when it is calculated that its performance is not what it should be based on the parameters obtained by the sensory means associated with the collector. As previously stated, the collector can self-orient itself using any known self-orientation system, based on the calculation of the sun's angle of incidence, assisted by one or more photovoltaic panels that ensure its total autonomy. Furthermore, the collector can also be tilted on one of its ends to control the azimuth. For this purpose, and as shown in Figure 6, one of the device's end support frames has a scissor-type structure (5-5), adjustable by means of a transverse worm screw (16), which threads into two nuts (17) associated with the intermediate joints of the scissor structure, and which will be controlled by an electric motor (18) associated with the device's control electronics. According to Figure 4, the parabolic reflection surface (1) is intended to include in its middle zone a series of sectors (13) which, being also of a reflective nature, act as hinged gates with respect to axes (14), against the tension of a spring, thus determining passive safety means against strong gusts of wind (15). Although it is not shown in the figures, on the area of the vacuum tube (2) that is not affected by the parabolic reflection surface (1), a Fresnell-type concentrating lens can be placed, which would be attached to the supporting structure of the parabolic reflection surface (1) in order to never interfere with it.
Claims
1. A parabolic concentrating solar collector, of the type that includes a parabolic reflecting surface (1) associated with programmed and / or calculated real-time solar tracking means, as well as an element on which the solar radiation is concentrated, wherein the element on which the solar radiation is concentrated is a vacuum tube (2), with its corresponding inlet (3) and outlet (4) of the fluid to be heated, duly insulated, with the particularity that the vacuum tube (2) is statically arranged on a frame (5), the parabolic reflecting surface (1) being provided to include means for complete and controlled tilting with respect to the imaginary central (6) and longitudinal axis of the vacuum tube (2), in which bearings or bushings participate through which the conduits associated with the inlet (3) and outlet (4) of the vacuum tube pass,not being affected by the angular displacements of the parabolic reflecting surface (1), with the particularity that the chamber through which the fluid to be heated circulates in the vacuum tube (2) is subdivided into two concentric chambers, an inner chamber (19), through which the cold fluid is fed, open at one end through which it communicates with an outer chamber (20), concentric to it, on which the solar radiation is concentrated within the vacuum tube, the inlet section to the inner chamber (19) being the same as the outlet section of the outer chamber (20), and characterized in that the parabolic reflecting surface (1) includes passive safety means against strong winds, materialized in sectors (13) of a reflective nature, in the form of hinged gates with respect to axes (14), against the tension of a spring.
2. Parabolic concentrating solar collector, according to claim 1,characterized in that a helical deflector (21) is arranged between the inner chamber (19) and the outer chamber (20) of the vacuum tube (2).
3. Parabolic concentrating solar collector, according to claim 1, characterized in that the parabolic reflection surface (1) is linked to the structure of the vacuum tube (2) through its lateral ends by means of arms (7) that converge in a bearing or axial bearing on the imaginary longitudinal and mean axis of the vacuum tube, it being provided that in correspondence with the inlet and outlet (3-4) of the vacuum tube, the arms (7) are fixed to a ring (8), which in turn is fixed to a toothed wheel (9) in which a pinion (10) meshes, associated with a small electric motor (11), fixed to the structure associated with the vacuum tube (2).
4. Parabolic concentrating solar collector, according to claim 1,characterized in that the frame (5) incorporates pressurized water-projecting nozzles (12) against the parabolic reflecting surface (1).
5. Parabolic concentrating solar collector, according to claim 1, characterized in that a Fresnell-type concentrating lens, integral with the supporting structure of said parabolic reflecting surface (1), is arranged over the area of the vacuum tube (2) that is not affected by the parabolic reflecting surface (1).
6. Parabolic concentrating solar collector, according to claim 1, characterized in that the vacuum tube (2) and consequently the parabolic reflecting surface (1) are arranged horizontally with respect to their longitudinal axis.
7. Parabolic concentrating solar collector, according to claim 1, characterized in that the vacuum tube (2) and consequently the parabolic reflecting surface (1),They adopt a vertical arrangement with respect to their longitudinal axis.
8. Parabolic concentrating solar collector, according to claim 1, characterized in that it includes at least one photovoltaic panel for powering the collector's control electronics.
9. Parabolic concentrating solar collector, according to claim 1, characterized in that one of the device's end support frames has a scissor-type structure (5'- 5''), adjustable by means of a transverse worm screw (16), which threads into respective nuts (17) associated with the intermediate joints of the scissor structure, and which is controlled by an electric motor (18) associated with the device's control electronics.