ES2311347B1 - SOLAR RADIATION FLAT CAPTURE AND PROCEDURE FOR OBTAINING THE BLACKED SURFACE OF THE ABSORBENT PLATE. - Google Patents

Abstract

Flat solar radiation collector and procedure for obtaining the blackened surface of your absorbent plate, for simultaneous heating of water and air with a box (4) covered by a frame (6) with the outer glass (7) fastened by a special silicone, with an elastic seal insulator (10), which closes it tightly; and a crystal (11) inside, housing an absorbent plate consisting of a tube (1) serpentine, oval that has a fin (2) of thin sheet, whose face view is blackened by embedding in it of graphite particles, by an electrical procedure, in which both elements are used as electrodes, applying a difference of electrical potential to said electrodes and causing a fire between them, obtaining a dark and rough surface with a high absorption coefficient of solar radiation.

Description

Flat solar radiation collector and procedure for obtaining the blackened surface of your absorbent plate

Object of the invention

The invention relates, as expressed by the set forth in this specification, to a flat sensor of solar radiation and the procedure for obtaining the blackened surface of its absorbent plate.

Specifically the object that the invention advocates consists of a flat solar radiation sensor, applicable to water and air heating for both domestic and domestic use industrial, whose main innovative feature constitutes it, In addition to the double glazing of its roof, its channel shape and its dual capacity for simultaneous heating of water and air, the procedure used to blacken the surface of the absorbent plate that incorporates by applying to it graphite or similar conductive material, thus giving it advantages and innovative features that significantly improve systems currently known for the same purpose.

Scope

The field of application of the present invention It is the industry dedicated to the manufacture of appliances and devices intended to capture solar radiation.

Background of the invention

The growing demand for thermal energy leads to the use of solar energy as an alternative to compensate for the shortage and limitations of other energy sources that in themselves they are in most cases contaminants.

The main barriers to the development of solar thermal energy are economic and technological, for which the flat sensor proposed by the present invention can have a lower physical performance than those manufactured with high technology, but its economic performance exceeds and compensates for The most sophisticated.

The most abundant type of collectors, or more extended in the market, are those that use water or other liquid to transfer heat, with very few using the air, being almost as economical to manufacture them to be able to apply both fluids, either individually or simultaneously.

Solar energy collectors with circulation of air, they must avoid the formation of fog inside, since in this case, the performance drops due to the shadow it casts on the absorbent plate for a considerable period of time, circumstance that with the existing devices in the market does not It always gets.

It should be noted, that the most important part of a solar radiation collector is the absorbent plate, the which must absorb the maximum energy for what the surface exposed to blackened solar radiation in order to increase the absorption coefficient of it existing for it different treatments or different techniques.

The most economical sensors use special paints to cover said surface, which implies add a heat resistance to heat transfer and, as consequence of the high temperatures to which it is subjected and at other chemical phenomena, this deteriorates decreasing its efficiency and therefore its performance and its useful life.

Other sensors, equipped with more technology sophisticated, get more effective selective surfaces and durable, but expensive, presenting some of them difficulties when applied in curves, in tubes and corners, being on the other hand little resistant to the high temperatures which must be supported if they are applied in collectors concentrators

For the manufacture of the selective surface of a solar radiation absorbing plate, it is necessary to take into account different factors: that it is easy to obtain, that its cost is not excessively high and have good durability, naturally adding to these requirements a high absorbency and low thermal emission.

The loss of thermal energy of a plate absorbent due to its emission, especially when its temperature is high, since it increases exponentially, is transferred largely to the air chamber between said plate and the crystal, the same happens with the loss of convection, if the air of this chamber is circulating, much of this energy is transported to the harvesting system.

Thus, a selective surface disqualified by its high irradiation may be interesting because it is more economic due to its manufacture, and because with the sensor that the The present invention proposes, the energy emitted with the air circulation, at the same time the temperature of I work to keep it in the most optimal values.

On the other hand, as is known, the use of solar thermal energy for cold production is based on the absorption machines, which need more temperature than the which normally reaches a flat sensor with a single crystal in its cover.

In this way, incorporating a second crystal finer, as advocated by the sensor of the invention, is manages to increase the temperature a few degrees without reducing appreciably its thermal performance.

This application also achieves take advantage of the remaining thermal radiation in the months of summer.

On the other hand, it covers the lack existing in the market for corrugated sensors, which are connected in series and in parallel they form a hermetic panel to be installed so simple and thus cover the roofs of buildings facing south replacing conventional tiles.

Thus, the flat solar thermal energy collector that the invention proposes, constitutes by itself an obvious new within its field of application, since it is worth mentioning that the applicant is unaware of the existence of a flat sensor of solar radiation that has technical characteristics, structural and constitutive similar to those advocated by the present invention, which is intended to solve the inconveniences and problems described above.

Explanation of the invention.

Specifically, the sensor of the invention it is essentially constituted from a box or housing in rectangular tray shape, preferably aluminum or polyester reinforced with glass fiber.

This box is tightly closed presented a transparent cover closed by a frame with two layers of glass, its entire inner surface being covered of thermal insulation, on which, supported on the base is the solar radiation absorbing plate.

Said plate incorporates a single continuous tube in form of coil, which has been pressed to acquire a oval section, in order to present a larger area under directly to the radiation and to cast the minimum possible shade on the plate.

The mentioned tube, preferably made copper, welded around a series of plates thin of the same material, so that the rest of the surface of the absorbent plate.

The clamping of the plate is resolved by four pins welded on the curved part of the tube, attached to brackets in the form of square and insulating material, subject to the side walls of the box.

The treatment that is applied to the surface absorbent to blacken it without the use of pigments, and that It is an essential characterizing part of the present invention, it is a procedure that is performed by applying graphite or similar material that is equally conductive to the electricity.

Said procedure consists in blackening the absorbent plate of copper, or other metal or metal alloy, by including in it particles of said graphite or similar material, resulting in obtaining a dark and rough surface with a high absorption coefficient of solar radiation together with high resistance to high temperatures as well as great durability.

The inclusion of such particles in the plate metal is made by an electrical procedure, since being both conductive elements are used as electrodes, of way that by applying an electric potential difference to said electrodes and causing a fire between them, similar to used in arc welding, the surface contamination by graphite particles providing the desired dark color and rough finish that, such As mentioned, it increases performance in the process of radiation absorption in the plate.

By applying the potential difference between the graphite and the plate and cause the fire between the two, the arc produced voltaic melts the metal plate locally producing the graphite inlay in it.

The variation of the different factors involved in the process allows their optimization to achieve different surface finishes looking for always the maximum absorption and the minimum irradiation of the energy solar received.

The elements that can be varied for obtained surface optimization are many, and its combination considerably increases the number of possible results obtained, being among others:

- The application of different metals or alloys used as an electrode to deposit its particles on another metal or base alloy.

- The degree of oxidation of the base metal.

- The pre-fire application of others oxides on the surface to be treated.

- The different forms or configurations that You can present the electrode.

- The procedure of causing the fuse like this as the frequency of vibration or percussion.

- The current used alternating or continuous.

- Its intensity.

- The polarity given to the electrodes in DC.

As electrode, the graphite and as a base sheet preferably copper, due to which applied in sensors of one and two crystals not very airtight, the experience of more than two decades of exposure to the radiation has not shown any alteration appreciably in the coloration of the plate or oxidation thereof, demonstrating thereby making the plaque blackening procedure absorbent that the invention advocates is virtually unalterable regarding their normal working conditions.

Looking at the industrial production of the invention, it should be noted that this is susceptible to manufacturing automated, requiring only a system that allows having activated several electrodes that travel the metal surface to try accompanied by a simple ventilation system for refrigeration.

Finally, it is also remarkable that said procedure is not polluting for the environment and is low cost since the amount of graphite or similar material that Used in the donor electrode is insignificant.

It should be noted, on the other hand, that the collector of the invention has means to allow the coupling of several units in series forming rows, getting a shielding of the tubular connections of the coil water circulation as well as the conduction sleeves of air, also providing means for joining some rows with the adjoining ones so that you can get to cover a determined surface, so it is suitable for use as a substitute for conventional tiles to form the roof of buildings, resulting in a very tight cover, easy installation and with less weight than conventional tiles.

The hot air obtained can be used for heating by passing it through a closed circuit, which can be done simply and economically on site new, since virtually all floors are built with hollow vaults, so there is a large air duct between two beams, insulating their ends as far as possible, and with some communications for the circulation of the air, with its corresponding input and output, a circuit can be achieved closed associated to the cover sensors. In this way the hot air in circulation dissipates its heat directly in the materials that integrate the slab behaving like a circuit secondary receiver.

Other utilities of air circulation we find in industrial dryers, as well as to cool the inside the collector avoiding overheating or formation of fog in wet weather.

Being fastened by screwing both the cover as the profiles that make it up, the collector allows a Easy disassembly of your cover, quickly and easily, what which offers great advantages when it comes to repair or replace any component inside it without the need for peel off the glass or disassemble the sensor from its installation.

On the other hand, if the collector is employed in systems that require low temperature, the inner glass can optionally suppressed without further complication, since said Crystal serves to reach a few more degrees of temperature.

Finally, a simple installation system of the sensor of the invention as a roof of buildings, especially in new constructions, it would be its assembly on a structure metal of rectangular meshes, of measures such that they serve as support to the four edges of the box, being the subject of this to the structure made by means of brackets located in the housing where the connections are located of the tubes.

The new flat thermal energy collector solar represents, therefore, an innovative structure of structural and constitutive characteristics unknown up to now for that purpose, reasons that together with its practical utility, the provide sufficient grounds to obtain the privilege of exclusivity requested.

Description of the drawings

To complement the description that is being performing and in order to help a better understanding of the characteristics of the invention, is attached herein descriptive, as an integral part of it, of a game of planes, in which with an illustrative and non-limiting nature, represented the following:

Figure number 1.- Shows a view in elevation of the absorbent plate incorporating the sensor of the invention.

Figure number 2.- Shows a view in section according to a cross-section and in detail of the side of the sensor in which the different elements that the configure as well as the plate clamping mode.

Figure number 3.- Shows a view in fragmented and exploding perspective of the bottom of the box and the different exterior components that make up the collector

Preferred Embodiment of the Invention

In view of the aforementioned figures and of according to the numbering adopted, you can see in them a preferred embodiment of the flat radiation sensor solar comprising the parts indicated and described to continuation.

Thus, in figure 1 the plate can be seen absorbent incorporating the sensor of the invention, which It consists of a tube (1) of a single piece in the form of a coil, whose section, as seen in figure 2, is oval except the vicinity to the nozzles where it is circular to couple the connection fittings.

Each zone or section of coil has both sides welded a fin (2) of thin sheet, whose face is blackened with graphite by the procedure described previously in the preceding section.

For its support, the plate has four pins (3) projections, welded to fin ends (2) in the curved area of the tube (1), as shown in the figure one.

In figure 2, it can be seen as the sensor it is essentially constituted from a box (4) that is configure as the base to which all its components are fixed, presented its upper edge an inward fold in all its perimeter forming a tab (5).

The cover is formed by a frame glass holder (6) preferably of aluminum, whose profile adopts a form of "Z", which minimizes the collector surface.

In the upper branch of the mentioned frame (6) place the outer glass (7) held by a special silicone which allows to resist the high temperatures that will be seen submitted, leaving a perimeter margin for the screws clamping (8), which incorporate a washer (9) in order to avoid thermal bridge between the frame (6) and the box (4), being threaded to the flange (5) of the box (4) where the gasket is located elastic insulator (10), which looks like a pad compressed between the frame (6) and the tab (5) of the box (4), of so that it is closed tightly.

In the lower frame branch (6) in the form of "Z", narrower than the upper one, rests a second crystal (11) finer, divided transversely into two equal parts, having all its polished edges, and being subject to that frame (6) with an elastic adhesive that allows some mobility, in order to avoid tensions and possible thermal breakage to cause of the high temperatures to which it is subjected.

For the introduction of the two halves of the mentioned glass (11) in its housing, these slide to through the groove (6a) that for this purpose presents the wall of the frame (6) in its upper part, the tab being in that part lower support glass (11) replaced by a ribbon (26) of quadrangular section to give it greater rigidity and avoid Cimbreo

For its part, to hold the plate absorbent are provided four supports (12), of material square shaped insulator internally attached conventional by means of screws threaded from the outside to said brackets (12), arranged in coincidence with the pins (3) that incorporates the plate to which they are fastened by screws (13) with Washers (14) of thermal insulation of ceramic material.

Continuing with figure 2, it looks like the Interior insulation is fiberglass and consists of three parts differentiated: the first part (15) is very spongy covering the entire inner surface of the box (4), filling in all corners and gaps thereof; the second part of the insulation (16r is semi-rigid, thicker and stands only at the base of the box (4) with a low aluminum plate the absorbent plate on which it rests; and finally the last part of the insulation (17) is very rigid and is located in the side walls of the box (4) with a painted aluminum layer in black and attached to the frame (6) glass holder.

The collector presents in both edges upper of its longitudinal sides a profile (18) in the form of "T" lying down, which supports its central branch on the glass exterior (7) by a seal (19) of airtightness or tightness, being fixed with screws (20) threaded to the box (4) without touching the frame (6).

Two profiles (21), section in "L" for the transverse sides, as seen in figure 3, are hold the box (4) by means of corresponding equal joints shape to that described for profiles (18) in "T".

In the lower transverse part, as you can also observed in figure 3, the sensor of the invention incorporates a corrugated sheet (22), which is sealed tightly to the bottom profile (21) and pressed with screws shorts that thread on said profile (21), which is arranged form protruding from the box (4) forming a cantilever that mounted on the upper cross section (21) of a possible second solar radiation sensor located in a row, so the covering or shielding of the connections is achieved tubular (1) of the water coil and the sleeves air circulation, allowing the serial connection of the collectors

Joining several rows of laterally sensors and connecting them to each other the width is achieved necessary to cover a certain surface, being necessary for said lateral union of the collectors that the rows that these forms are as close as possible, so that the  respective longitudinal "T" profiles (18) are found in contact, being joined together with another profile (23) in the form of an inverted "U", as shown in the figure 3.

For air circulation the sensor counts with two nozzles (24), one inlet and one outlet, located in the central part of both transverse sides of the box (4), the which are formed by a short tube isolated from the walls of the box (4), as can be seen in figure 3, so that match the air chamber between the absorbent plate and the inner glass (11), which in turn is in communication with the air chamber that is between the outer glass (7) and the inside (11) through the holes (25) presented by the frame (6) on its lower transverse side as well as the groove (6a) of the opposite side described above, intended for mounting the inner glass (11).

A possible collector installation system of the invention as a roof of buildings, may consist of its mounting on a metal structure of rectangular meshes, with measures that support the four edges of the box, being the subjection of this to the structure realized by means of supports in square shape located in the housing where find the connections of the tubes, being two of said brackets attached to the structure by means of a clamp bridge (27) that allows the movement of the sensor through the dilation effect, especially when the box is made of aluminum.

Describe sufficiently the nature of the The present invention, as well as how to implement it, is it states that, within its essentiality, it may be taken to the practice in other embodiments that differ in detail from the one indicated by way of example, and which will reach also the protection that is collected as long as it is not altered, change or modify its fundamental principle.

Claims (11)

1. Flat solar radiation collector, of the type intended for the simultaneous heating of water and air for both domestic and industrial use, characterized by the fact that it comprises a box (4) that has a flange (5) on its upper edge, covered by a glass frame (6) of section in the form of "Z", on the upper branch of which the outer glass (7) is attached by means of a special silicone, leaving a perimeter margin for the fastening screws (8), which incorporate a washer (9) threaded to the flange (5) where the insulating elastic joint (10) is located, which is like a compressed pad between the frame (6) and the flange (5) of the box (4), of so that it is closed tightly; and on the lower branch of the frame (6), a second crystal (11) is supported, transversely divided into two equal parts, secured with an elastic adhesive; housing inside an absorbent plate consisting of a tube, (1) of a single piece in the form of a coil, oval section except for the vicinity of the nozzles where it is circular to fit the connection fittings; in which each section of coil has on both sides welded a fin (2) of thin sheet, whose face is blackened. 2. Flat solar radiation sensor according to claim 1, characterized in that for the introduction of the two halves of the glass (11) in its housing, the wall of the frame (6) in its upper part has a slot (6a), the lower support flange of the glass (11) being replaced by a ribbon (26) of quadrangular section. 3. Flat solar radiation sensor according to claims 1 and 2, characterized in that the absorption plate has four protruding pins (3), welded to the ends of the fins (2) in the curved area of the tube (1), and because four brackets (12) are provided, of insulating material in the form of a square internally fastened in a conventional manner by means of screws threaded from the outside to said support, arranged in coincidence with the pins (3) that incorporates the plate a those that are fastened by screws (13) with washers (14) of thermal insulation of ceramic material. 4. Flat solar radiation sensor, according to claims 1 to 3, characterized in that the inner fiberglass insulation consists of three distinct parts: a very spongy first part (15) covering the entire inner surface of the box (4), a second part of the semi-rigid, thicker insulation (16) that is located at the base of the box (4) with an aluminum plate under the absorbent plate on which it rests, and a last part of the very rigid insulation (17) that is placed on the side walls of the box (4) with a layer of black painted aluminum and attached to the frame (6) glass holder. 5. Flat solar radiation sensor, according to claims 1 to 4, characterized in that it has a lying "T" profile (18) in the two upper edges of its longitudinal sides, which supports its central branch on the outer glass (7) by means of a heat seal (19), being fixed with screws (20) threaded to the box (4) without touching the frame (6), and because two profiles (21), section in " L "for the transverse sides, are fastened to the box (4) by corresponding joints in the same way as the profiles (18) in" T ". 6. Flat solar radiation sensor, according to claims 1 to 5, characterized in that in the lower transverse part, it incorporates a corrugated sheet {22), hermetically sealed to the lower profile (21) and pressed with short threaded screws in said profile (21), arranged so that it protrudes from the housing (4) forming a cantilever suitable for mounting on the upper transverse profile (21) of a second solar radiation sensor located in a row, whereby the covering is achieved or shielding of the tubular connections (1) of the water coil and air circulation sleeves, allowing its connection in series. 7. Flat solar radiation collector according to claims 1 to 6, characterized in that the respective longitudinal "T" profiles (18) of adjacent rows of collectors connected in series are joined together by a profile (23 ) in the form of an inverted "U". 8. Flat solar radiation sensor, according to claims 1 to 7, characterized in that for the air circulation the sensor has two nozzles (24), one inlet and one outlet, located in the central part of both transverse sides of the box (4), formed by a short tube isolated from the walls of the box (4), so that they coincide with the air chamber between the absorbent plate and the inner glass (11), which in turn it is in communication with the air chamber that is between the outer glass (7) and the inner one (11) through the holes (25) presented by the frame (6) on its lower transverse side as well as the slot (6a) on the opposite side. 9. Procedure for obtaining the blackened surface of the absorber plate of a flat solar radiation sensor, according to claims 1 to 8, characterized in that it consists of blackening the absorbing plate of copper, or other metal or metal alloy , by embedding in it graphite particles or similar material also conductive to electricity, obtaining a dark and rough surface with a high coefficient of absorption of solar radiation. 10. Method for obtaining the blackened surface of the absorber plate of a flat solar radiation sensor, according to claim 9, characterized in that the inclusion of the graphite particles or similar conductive material in the metal plate is It is carried out by means of an electrical procedure, in which both elements are used as electrodes, applying a difference in electrical potential to said electrodes and causing a flue between the two, such as in electric arc welding, so that the produced arc melts locally the metal plate producing the embedding of graphite or similar conductive material in it. 11. Procedure for obtaining the blackened surface of the absorber plate of a flat solar radiation sensor, according to claims 9 and 10, characterized in that the variation of the different factors involved in the process allows the optimization of the same to achieve different surface finishes, these being many and their combination being able to considerably increase the number of possible results obtained.