Patent Application
20220373228
The invention relates to a device with a heat exchanger with a first flow, through which a first gaseous heat transfer medium passes, and with a second flow, through which a second gaseous heat transfer medium passes, wherein upstream from the first flow, there is arranged a combustion chamber, which optionally extends into the first flow.
Known from US 2018/0347858 A1 is such a device, in which a thermal solar installation is combined with a burner for an air-gas mixture. The known device, however, is disadvantageous, since the burner must be arranged directly in the area of the solar installation or its concave mirror, which represents a certain safety risk, and under certain circumstances, the heat exchanger is far away from the installation in which the generated heat is required.
The object of the invention is to provide corrective actions here.
According to the invention, two feed lines are attached to the first flow, the first feed line of which is connected to a thermal solar installation. The second feed line can, if necessary, be connected to a source for a combustible gas-air mixture or for a non-combustible gas, in particular an oxygen-containing gas, such as air. When the thermal solar installation produces enough heat, only the heated gas from the solar installation is fed to the first flow of the heat exchanger. When the thermal solar installation does not produce enough heat, only combustible gas-air mixture is fed to the first flow of the heat exchanger in one embodiment of the invention, which mixture is burned in the combustion chamber.
To ignite the combustible gas-air mixture, an igniting system can, if necessary, be arranged in the combustion chamber.
In order to control the flow through the feed lines, it can be provided in one embodiment of the invention that a valve is arranged in the second feed line, which valve connects the second feed line to a line to the thermal solar installation and interrupts the connection of the second feed line to the heat exchanger or controls the flow through the second feed line. The gas of the second feed line (in this first case, a combustible gas-air mixture) can thus be fed either directly to the heat exchanger or the gas (in this second case, for example, pure air) is not fed directly to the heat exchanger, but rather is diverted over the line to the solar installation and its first feed line if a solar operation is possible. A preferred temperature range at which the gas of the solar installation is heated is within the order of magnitude of 500° C. to 1500° C., preferably between 600° C. and 1200° C., especially preferably between 700° C. and 1000° C.
An embodiment of the invention is also possible in which the gas fed to the solar installation is not only pure air, but rather fuel is also fed to the latter, which fuel subsequently burns in the combustion chamber. This embodiment is advantageous when the gas, e.g., in the case of overcast skies, is heated in the solar installation but not to a high enough temperature. Gas at a high enough temperature can ultimately be produced in the combustion chamber by the fuel. In this embodiment, it should be ensured that the temperature at which the gas is heated in the solar installation and the degree of saturation of the fuel-air mixture are matched to one another, so that there is no combustion or deflagration in the solar installation. The temperature range at which the gas is heated in the solar installation in this embodiment is preferably between 400° C. and 600° C., and the mixing ratio of the fuel-air mixture is hyper-stoichiometric, i.e., excess air is present, preferably at a ratio of 1.5:1 to 3:1, preferably 2:1 to 2.5:1.
If the temperature of the gas in the solar installation is not high enough, in an alternative embodiment of the invention, fuel can also be fed by means of a system directly into the combustion chamber (sprayed in the case of liquid fuels or injected in the case of gaseous fuels). The system for feeding fuel can also be used when the solar installation is not in operation at all and only an oxygen-containing gas, such as air, is fed through the second feed line directly to the combustion chamber.
Gas, in particular biogas or hydrogen, is preferably used as fuel.
When control valves are used rather than cutoff valves or changeover valves, other mixed forms of operation can be achieved.
One advantage of the device according to the invention is in any case that the heat exchanger must not be located in immediate proximity to the thermal solar installation and that because of the separate feeding of gas from the solar installation through the first feed line and of the optionally combustible gas-air mixture through the second feed line and the above-described combination options, more reliable and easily controllable operational management is made possible.
Within the scope of the invention, any known thermal solar installation can be used, with which a hot gas, preferably hot air, can be produced at the desired temperature.
It is preferred within the scope of the invention, however, when the solar installation has a concave mirror, preferably a parabolic mirror, i.e., a concave mirror in the form of a paraboloid of revolution, since with such a mirror, high temperatures can be generated at the focal point of the mirror.
In the invention, the concave mirror must not have the shape of an ideal parabolic mirror in its entirety, although this is advisable for optimum use of the solar energy. It can also be sufficient, however, when the concave mirror has a parabolically-curved mirror surface at least in sections. In particular, the concave mirror in sections can also have a (optionally approximately) cone-shaped mirror surface.
Since the concave mirror is usually located outdoors, it is advantageous when the latter can be protected from effects of the weather, in particular strong wind. This is done according to the invention in that the mirror surface is formed at least in part from adjustable sections.
For this purpose, there are multiple options in turn according to the invention. One option is that on its base, the concave mirror will have a bowl with a parabolic mirror surface and that the adjustable sections are arranged to pivot on the bowl. The fins that are mounted to pivot on the edge of the bowl and that extend essentially in the direction of the generatrixes of the concave mirror or parabolic mirror can be pivoted inward, i.e., approximately in the direction toward the center of the mirror, at which point not only is the attack surface of the concave mirror reduced, but also the mirror surfaces of both the bowl and the fins are protected, since the bowl is covered by the fins and the mirror surfaces of the fins are folded inward or downward.
In an alternative embodiment, the adjustable sections are annular fins that, starting from the bowl, are aligned in the direction of the axis of the paraboloid. That is to say that an annular fin connects to the bowl and the additional, optionally present annular fin(s) then connects or connect successively to one another when the concave mirror is located in its operating position. When the solar installation is not in operation, the annular fins can be lowered in the direction of the axis of the concave mirror or parabolic mirror, so that the latter are approximately at the height of the bowl and surround the latter.
When using a concave mirror or a parabolic mirror, a heating head is arranged in its interior, preferably at the focal point.
In the invention, it is also possible or preferred when at least one section of the concave mirror is approximately the shape of a cone, and optionally in addition, a base or a subpart of the concave mirror is shaped like a paraboloid of revolution or the like. This makes it possible to focus the sun rays not specifically on the focal point at which the heating head is found, which in particular in the case of larger concave mirrors would generate very high local temperatures in individual areas of the heating head, but rather to distribute the rays uniformly onto the illuminated surface of the heating head.
According to the invention, the heating head is arranged on the end of a holding device, which has two concentric, preferably insulated, pipes, which between them form a line in the form of an annular gap, through which the supply of cooler gaseous heat transfer medium to the heating head is done, wherein the removal of hotter, gaseous heat transfer medium is done through the inner pipe.
The heating head is thus arranged on a holding device, wherein the holding device is itself formed not necessarily but preferably by the two concentric pipes. As a result, a very simple design of the device is produced.
Another possibility for protecting the concave mirror from effects of the weather consists according to the invention in that the concave mirror is arranged to move relative to the holding device and the heating head. In this way, the concave mirror, when the holding device is arranged, for example, to be vertical, can be moved from a raised position into a lowered position. In this lowered position, the concave mirror can also be protected, if necessary, by a housing, roof, or the like.
The holding device itself with the heating head is in this case preferably arranged to be stationary, which offers the advantage that the heating head, which is optionally still very hot from its operation, also remains in the original operating position when the concave mirror is lowered, in which position the danger that a fire will be started by the still-hot heating head is extremely low.
In order to have the solar installation track the sun, the concave mirror—as is known in the art—can be arranged to pivot in the vertical direction relative to the holding device. To this end, the concave mirror can have a slot that, preferably starting from the axis of the concave mirror, is arranged along a generatrix of the concave mirror, wherein the holding device is run through the slot.
Additional preferred embodiments of the invention are the subject matter of the other subclaims.
Additional features and advantages of the invention are given in the following description of preferred embodiments of the invention that do not limit the scope of protection with reference to the attached drawings. Here:
In the drawings, embodiments of devices according to the invention are depicted, which devices, however, are intended only as examples and, aside from the features according to the invention as defined in the claims, can also be implemented differently within the scope of this invention as regards many components, without this requiring special mention below.
In
The two feed lines empty into a combustion chamber 4, from which a first flow starts from the heat exchanger 1, which is indicated symbolically by the arrow 5. A second flow from the heat exchanger is formed by, for example, pipes 6, through which flows an additional fluid heat transfer medium, which is preferably gaseous, but can also be liquid for certain applications. The combustion chamber 4 is bounded by a base 7, in which the pipes 6 are mounted, a boundary wall 8, and a cover 9. The base 20 can form the wall of a cylinder, e.g., of a compression thermal engine, at the same time.
Between the boundary wall 8 and the cover 9, there is an open annular gap 10, through which the gaseous heat transfer medium can escape from the chamber 4 after it has released a large part of its heat to the heat transfer medium in the pipes 6. After the gaseous heat transfer medium has exited from the chamber 4 through the annular gap 10, it escapes downward and through an outlet 13 through an inner annular space 11, which is bounded by the boundary wall 8 and an inner dividing wall 12. In this case, residual heat is transferred from the escaping gas to the inflowing gas.
The gas fed by the second feed line 3 is first run through two annular spaces 14, 15, and the first flow 5 also enters into the combustion chamber 4 in the position, depicted in
The valve 21, with which the flow of the gas that flows in through the middle annular space 15 can be diverted, is located upstream from an inlet opening 19. When the valve is in the position that is depicted in
The gas, which in the case of a valve position according to
In one embodiment of the invention, fuel can be fed directly into the combustion chamber 4 by means of a system, for example one or more nozzles 20. The heat exchanger 1 according to the invention can then be used even if the solar installation is not in operation at all or does not provide enough heat, and only an oxygen-containing gas such as air is fed through the second feed line directly to the combustion chamber.
To ignite the fuel in the combustion chamber 4, an igniting system 16 can be used.
The arrangement, depicted in
With reference to the drawings of
The embodiments of concave mirrors according to
In
Because of this tilting of the swivel axes 31, the fins 28 are adjusted not radially inward but rather obliquely to the radial direction when pivoting from their operating position, depicted in
As a swivel drive 34 for the fins 28, in the depicted embodiment of the invention, two pressure-medium cylinders 39, e.g., hydraulic or pneumatic cylinders, are used, which cylinders are mounted on opposite sides of the bowl 26 on a holding device 38 of the bowl 26. A piston 40 of the respective pressure-medium cylinder 39 is connected to a ring 41 that surrounds the bowl 26. Fastened to the fins 28 are rods 42, on whose free ends tension springs 43 are mounted, which rods are mounted at their other ends to attachments 44 on the bowl 26.
When the pistons 40 are run out by increasing the pressure in the cylinders 39, the ring 41 drives the rods 42 upward, by which the rods 42 pivot the fins 28 in the direction toward the center of the bowl 26. If, in contrast, the pressure in the cylinders 39 is released, the tension springs 43 pull the rods 42 back down again, by which the fins 28 are pivoted around the pivot bearings 29 again from the resting position into the operating position.
In
As a swivel drive 34 for the fins 45, in this embodiment, only a single pressure-medium cylinder 39, e.g., a hydraulic or pneumatic cylinder, is used, which, on the one hand, is mounted on a holding device 38 on the bowl 26 and, on the other hand, is mounted on one of the fins 45. When the piston 40 of the swivel drive 34 is run out, the nearest fin 45 is successively driven inward, in each case counterclockwise, as can be seen in
This embodiment has the advantage that only a single fin 45 has to be pivoted by means of a swivel drive 34, and the thus actively-pivoted fin 45 successively entrains all other fins 45, since the latter also successively overlap the respective longitudinal edges 35.
In
Unlike in the embodiment according to
For purposes of illustration, the fins 28a of the inner row are depicted in the resting position and the fins 28b of the outer row are depicted in the operating position in
In all described embodiments, each fin 28, 28a, 28b, 45 has an offset 36 on a longitudinal edge 35, with which offset it rests on the longitudinal edge 37 of the adjacent fin 28, 28a, 28b, 45. In the embodiment according to
In
In the embodiment depicted in
Between the edge 27 of the bowl 26 and the disk-shaped holding device 51, a total of four struts 52 are mounted, uniformly distributed around the periphery of the bowl 26. Struts 53 also arranged correspondingly are mounted on the lower fin 46a, which struts extend between an upper edge 54 of the lower fin 46a and strut 56, which lie in a radial plane and are arranged approximately at the height of the lower edge 55 of the fin 46a. The struts 52 and 53 are used to guide the overlying annular fins 46a, 46b in each case, when the fins 46a, 46b are moved from the operating position depicted in
The pressure-medium cylinder 48 in the depicted embodiment has a 2-stage piston 57, wherein each stage has approximately the height of a fin 46a, 46b. The upper stage 58 of the piston 57 is connected on its free end 61 to the upper edge 62 of the upper fin 46b. When the pressure is released from the pressure-medium cylinder 48, the annular fins 46a, 46b are lowered by their own weight and in this case successively drive the 2-stage piston 57 of the pressure-medium cylinder 48 into the cylinder 49, as is depicted in
In
In
If the traction element 68 is moved counterclockwise in the direction of the arrow 70, the annular fins 46a to 46d are also moved downward by their own weight until the resting position that is depicted in
The arms 71a to 71c on the three lower annular fins 46a to 46c only rest on the carriers 69a to 69c. The uppermost carrier 69d and the uppermost arm 71d are connected securely to one another, so that the fins 46a to 46c that are below the uppermost fin 46d are forced downward from the uppermost fin 46d if they do not automatically move downward under their own weight when the carriers 69a to 69c are moved downward.
In
As can be seen in the left half of
When, as depicted in the right half of
The thermal solar installation 23 according to the invention has a first embodiment, depicted in detail in
In the invention, any holding device can be used on which the heating head 74 is mounted, wherein the feeding and draining of the heat transfer medium have to be done via lines. In the case of the invention, however, it is preferred when the heating head 74 is arranged at the end of a rod-shaped or tube-like holding device 75, which has two concentric, preferably insulated, pipes 76, 77, which between them form an annular gap 78, wherein the feeding of the cooler, gaseous heat transfer medium to the heating head 74 is done through the annular gap 78 and the draining of the hotter, gaseous heat transfer medium is done through the inner pipe 76.
Each of the two pipes 76, 77 consists of an inner and outer casing 79, 81 with insulation 82 arranged in-between. On the end facing the heating head 74, the inner casings 79 of both pipes 76, 77 have a flange 83, projecting outward, as a spacer with respect to the outer casing 81 in each case. The outer casing 81 of the inner pipe 76 also has spacers 84 that are short, however, in the peripheral direction of the outer casing 81 only in order to hamper as little as possible the flow of the heat transfer medium through the annular gap 78 and into the heating head.
In the preferred embodiment depicted in the drawings, the heating head 74 has a rounded shape with a tapering section 85 in the area of the transition to the holding device 75. Because of the rounded shape, the sunbeams reflected by the concave mirror 24 on the heating head 74 strike preferably, for example, at a right angle to the surface of the heating head, which improves the effectiveness. Because of the tapering section 85, this is also possible for a larger portion of the sunbeams that strike the heating head 74 from below.
The heating head 74 is connected via a flange 86 to the tube-like holding device 75, wherein the annular gap 78 of the holding device 75 continues into an annular gap 87 in the heating head. The shape of the annular gap 87 that has an essentially consistent width is matched to the outside contour of the heating head 74 and is bounded by an outside wall 88 that is made adjacent to the flange 68 with consistent wall thickness.
At the crown 89 of the heating head 74, the latter has a central recess 91, which is located in extension of an inside pipe 92 of the heating head 74. The wall thickness of the outside wall 88 can thus also be kept largely constant even in the area where the annular gap 87 is curved inward on the crown 89 and turns into the inside pipe 92 of the heating head 74, which is in the extension of the inner pipe 76 of the holding device 75.
In
In order to further improve the transfer of heat from the outside wall 88 and the fins 109 to the gaseous heat transfer medium, the walls bounding the annular gap 87 and the flow channels 111 can be designed to be rough in such a way that the gaseous heat transfer medium flows in the form of a turbulent flow through the annular gap 87 and the flow channels 111.
In order to be able to follow in the vertical direction the position of the sun changing over the course of a day, a slot 93 is attached in the area of the base of the bowl 26 in all described embodiments of the solar installation 23 according to the invention, through which slot the holding device 75 is run. Along the holding device 75, a positioning element 94 can move, on which element, on the one hand, two struts 95 are mounted on opposite sides of the bowl 26, and, on the other hand, a pressure-medium cylinder 96 is mounted in a hinged manner. If the piston 97 of the pressure-medium cylinder 96 is run out, the concave mirror 24 is pivoted from the resting position, depicted in, for example,
So that the concave mirror 24 can follow the sun even in the horizontal direction, the struts 95 and the pressure-medium cylinder 96 are mounted on a flange 99 that can rotate relative to a guide sleeve 98. Arranged on the guide sleeve is a drive, not depicted, of a worm gear 101, which drives a worm 102, which is engaged with a worm wheel 103 on the flange 99. The sleeve 98 can move in the longitudinal direction of the holding device 75, but cannot rotate relative to the latter. By the drive with the worm gear 101, the concave mirror 24 can thus be rotated relative to the holding device 75.
The concave mirror 24 can move along the holding device 75, in order to be able to move it from a raised position (e.g.,
The heat released by the heat exchanger 1 according to the invention can continue to be used for any purpose, for example for heating buildings, plants, or production units, or else also can be fed to additional processes, such as thermal (thermodynamic) processes. In addition, the heat exchanger according to the invention can also be used in connection with a compression thermal engine, e.g., a Stirling engine, which has a first space for heating a working medium and a second space, connected to the first space, for cooling the working medium, wherein the working medium is heated in the first space via the heat exchanger according to the invention.
Reference Symbol List:
| Number | Date | Country | Kind |
|---|---|---|---|
| A 50912/2019 | Oct 2019 | AT | national |
This application is the U.S. national phase of International Application No. PCT/EP2020/077867 filed Oct. 5, 2020 which designated the U.S. and claims priority to AT A 50912/2019 filed Oct. 22, 2019, the entire contents of each of which are hereby incorporated by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2020/077867 | 10/5/2020 | WO |
