ITTO20110554A1 - HYBRID SOLAR PANEL - Google Patents

Description

â € œHybrid solar panelâ €

TEXT OF THE DESCRIPTION

Field of invention

The present invention refers to a hybrid solar panel, of the type comprising a plurality of photovoltaic cells and cooling means of the aforesaid photovoltaic cells arranged to transfer a thermal flow to a fluid, for example water, conveyed outside for other uses.

In particular, the invention refers to a hybrid photovoltaic panel comprising:

- a photovoltaic layer including a plurality of photovoltaic cells,

- a heat exchange layer including cooling means for said photovoltaic cells,

- a collector element designed to convey a fluid, particularly a liquid, in a heat exchange relationship with said heat exchange layer,

in which

the heat exchange layer comprises one or more heat conduit devices adapted to contain a heat transfer fluid and each comprising:

- an evaporation side of the heat-carrying fluid arranged to absorb a flow of heat from the photovoltaic cells and defining said cooling means, - a condensation side of the heat-carrying fluid in correspondence with which said collector element is applied,

in which the photovoltaic cells of the photovoltaic layer are applied in correspondence with the evaporation side of said one or more heat pipe devices and are in a heat exchange relationship with them.

Known technique

Hybrid solar panels are widely known in the technical field of reference and offer both the possibility of transforming the energy associated with solar radiation into electrical energy using photovoltaic cells as well as the possibility of heating a fluid, in particular a liquid, by means of a circuit. cooling of the photovoltaic cells themselves.

Various known solutions provide for the use of heat exchangers made with roll-bond technology and arranged in correspondence with a back of the photovoltaic cells. However, in the face of the undoubted benefits typical of solutions made with roll-bond technology, which include, for example, the very competitive cost, good performance and relative simplicity of implementation, there are a series of technical problems that cannot be considered solved.

In particular, the use of a heat exchanger made with roll-bond technology implies, due to the relatively small dimensions of the passage sections of the exchanger channels, of having to tolerate high pressure drops of the fluid inside the exchanger, with consequent increase in the power necessary for driving a pump into rotation which is designed to circulate a cooling fluid, in particular a liquid, inside the aforesaid exchanger.

The aforementioned problems are further aggravated by the fact that the cooling fluid used is in almost all cases water, which creates many problems in use with the aluminum alloys of which the heat exchangers produced with roll technology are made. bond.

In fact, in the presence of aqueous solutions, pure or alloy aluminum exhibits an amphoteric behavior, which makes it subject to destructive corrosion phenomena. In known solutions the problem is solved by means of additives which are periodically introduced into the cooling circuit, which however can cause encrustations and have a cost that is anything but negligible.

Moreover, hybrid solar panels of the known type made with heat exchangers produced with roll-bond technology sometimes have strong thermal unevenness between different areas of the panel which are accentuated during transients of operation. These thermal non-uniformities considerably reduce the efficiency of the photovoltaic cells, especially if they are connected in series.

In fact, it should not be forgotten that the efficiency of photovoltaic cells tends to increase as their temperature decreases, which is why cooling them is a beneficial fact not only because it allows to obtain a further useful energy effect, but also because it increases the conversion efficiency of photovoltaic cells.

A further known solution is illustrated in document WO-A-2011/032164, which illustrates a hybrid solar panel comprising a layer of photovoltaic cells arranged in arrays on the fins of respective heat pipe devices. As known to those skilled in the art, heat conduit devices comprise a heat transfer fluid inside them which undergoes two phase transitions, one inside an evaporation side (liquid-gaseous) the other inside a condensation side (gaseous-liquid) and function substantially as a thermal diode, i.e. there is a single direction of circulation of the heat-carrying fluid inside them and a single direction of heat transfer.

The photovoltaic cells are arranged on fins applied at the evaporation side of the heat conduit devices while the condensation sides of each heat conduit device are inserted in a head where they exchange heat with a fluid flowing inside it.

The solution illustrated in document WO-A-2011/032164 first of all presents a considerable complication from the constructive point of view. Furthermore, the heat conduit devices used have a tubular structure and having a single internal volume within which the phase changes of the heat transfer fluid occur, they are severely limited in their operation by problems of entrainment, i.e. migration of particles of the heat transfer fluid in phase. liquid in the gaseous stream of the same heat transfer fluid that rises towards the condensation side.

The structure of the hybrid solar panel presented in the aforementioned document is also decidedly not very compact and is therefore not very suitable for application in contexts that require the smallest possible footprint or easy camouflage of the solar panel.

Purpose of the invention

The purpose of the present invention is to solve the technical problems previously described.

In particular, the object of the invention is to provide a hybrid solar panel with a compact structure, of simple construction, low cost and high efficiency.

Summary of the invention

The object of the invention is achieved by a hybrid solar panel having the characteristics forming the subject of one or more of the following claims, which form an integral part of the technical teaching administered herein in relation to the invention.

In particular, the object is achieved by a hybrid solar panel having all the characteristics listed at the beginning of the present description and further characterized by the fact that each heat pipe device comprises a closed circuit arranged for the circulation of the heat-carrying fluid and including a first channel adapted to receive the heat-carrying fluid in the liquid phase from the condensation side and able to convey it towards at least a second channel, which is in turn able to carry the heat-carrying fluid in the vapor phase towards the condensation side, in which each device a heat conduit is made by joining a first and a second sheet of metal material in correspondence with areas delimiting said closed circuit of each heat conduit device.

Brief description of the figures

The invention will now be described with reference to the attached figures, given purely by way of non-limiting example, in which:

Figure 1 is a perspective view of a hybrid solar panel according to a preferred embodiment of the invention,

- figure 2 is an exploded perspective view of the solar panel of figure 1,

- figures 3 and 4 are plan views, respectively according to arrows III and IV of figure 2, of a component of the panel according to the intention,

- figures 5 and 6 are enlarged views of details indicated with arrows V and VI in figure 3,

- figures 7 and 8 are seen according to arrows VII and VIII of figure 1,

- figures 9 and 10 are sectional views according to the traces IX - IX and X - X respectively of figure 7.

- figure 11 illustrates a further embodiment of a component of the panel according to the invention, e

- figures 12, 13 are enlarged views of details indicated, respectively, with arrows XII, XIII in figure 11.

Detailed description

In figure 1 the reference number 1 indicates a hybrid solar panel according to a preferred embodiment of the present invention.

With reference also to Figure 2, the hybrid solar panel 1 comprises a photovoltaic layer 2 including a plurality of photovoltaic cells 4, a heat exchange layer 6 and a back panel 8, in which the heat exchange layer 6 is arranged between the photovoltaic layer 2 and the back panel 8. The solar panel 1 also comprises a collector element 10, inside which there is a duct 11, and a flange 12 arranged on opposite sides of the heat exchange element 6 externally with respect to to the photovoltaic layer 2 to the back panel 8.

With reference to Figure 1, the photovoltaic layer 2, the heat exchange state 6 and the back panel 8 are packaged together by means of a frame 14, preferably comprising metal profiles.

With reference to figures 3, 4, the heat exchange layer 6 comprises a plurality of heat conduit devices indicated with the reference number 16 containing a heat transfer fluid and made by joining a first and a second with roll-bond technology sheet S1, S2 of metallic material, preferably aluminum.

As known to those skilled in the art, roll-bond technology provides for the creation of cavities and / or channels, having any path, between two sheets of metal material by applying a serigraphy reproducing, substantially in plan, the path of the cavities and / or channels and the subsequent pressing and hot rolling of the sheet metal. This last operation causes the joining of the material only in correspondence with the areas where screen printing has not been applied, ie in correspondence with the areas delimiting the channels and / or the cavities.

Subsequently, the volumes of the cavities and / or channels take shape by pneumatic inflation, which involves the inoculation of pressurized air (typically between 90 and 130 bar) between the sheet metal sheets. The air pressure is in any case dependent on the thicknesses, the nature of the joined sheets and the conformation of the cavities and / or channels.

Each heat pipe device 16 comprises a closed circuit arranged for the circulation of the heat carrier fluid and comprising an evaporation side 18 and a condensation side 20 of the heat carrier fluid separated by an adiabatic zone 22.

Also called LC, LE and LA, the lengths, respectively, of the condensation side 18 and of the evaporation side 20 of each individual heat pipe device 16 and of the adiabatic zone 22, and also called LTOT their sum, typical values are:

- between 0.03 and 0.4 for LC / LTOT

- between 0.5 and 0.97 mm for LE / LTOT, e

- between 0.001 and 0.4 for LA / LTOT

The evaporation side 18 comprises a first channel 24 in fluid communication with a second channel 26 by means of a connection section 28, having a substantially U-shaped geometry and arranged at an opposite end with respect to the condensation side 20.

The latter comprises a reservoir 30 in fluid communication with the first channel 24 by means of an outflow mouth 32 and in fluid communication with the second channel 26 by means of an inlet mouth 34.

The term "tank" used in the present description is intended to indicate a portion of the closed circuit within which the heat-carrying fluid flows (and is temporarily accumulated), having significantly higher passage sections than those of the channels 24, 26 (and in general the rest of the circuit) and such as to introduce a localized hydraulic capacity in the closed circuit.

With reference to figures 5, 6, in a preferred embodiment the first channel 24 is in fluid communication with the outflow mouth 32 by means of a siphon duct generally indicated by the reference number 36. The siphon duct 36 comprises a first and a second loop 38, 40 arranged fluid-dynamically in series, in which - in this embodiment - the loop 38 is located at a distance D38 from the tank 30 greater than a distance D40 of the second loop 40 from the tank 30 itself . Furthermore, the loops 38,40 define a curved path having a substantially "S" shape comprising an outflow portion 38a which connects the outflow mouth 32 to the first loop 38, which creates a first curve with an amplitude preferably equal to 180 ° which joins a stretch of slope 40a. The rising portion 40a leads directly into the second loop 40, which in turn creates a second curve, preferably 180 ° wide, to then flow directly into the first channel 24.

It should be observed that the width of the curves of the loops 38,40 can be chosen at will, within the limits imposed by the function of the siphon duct 36, as will become clearer later on. Furthermore, using the tank 30 as a reference, the loop 40 has a higher geometric height than the loop 38. Using the same logic, the outflow mouth 32 has a lower geometric height compared to the inlet 34. Also the meaning of the term " geometric dimension "will be clearer in the following, with particular reference to the functional description of the solar panel 1.

With reference to Figures 3 to 6, it should also be noted that preferably the siphon duct 36 and the inflow and outflow openings 34, 32 are made on the condensation side 20.

Each first channel 24 is preferably bordered, along the evaporation side 18, by a first and a second thermal interruption 42, 44. The term "thermal interruption" is intended to designate a physical interruption of the material of the sheets S1, S2 or an insert of thermally insulating material or a combination of both, and in general any arrangement designed to limit the conductive heat exchange between the channel 24 and the surrounding metal material of the sheets S1, S2 - which substantially acts as a fin and is therefore potentially capable of conveying a massive thermal flux.

The thermal interruptions 42 and 44 substantially extend from a border area with the adiabatic zone 22 up to the connection section 28.

Furthermore, the thermal interruptions 42, 44 may include, for example, interruptions in the material of the sheets S1, S2 made by laser cutting, inserts of thermally insulating material or a combination thereof.

The adiabatic zone 22 comprises a plurality of openings having a substantially transverse orientation with respect to the first and second channels 24, 26 and comprising first openings 46 arranged between the channels 24, 26 of each heat pipe device 16 and a plurality of second openings 48 arranged channels 26 and 24 of adjacent heat pipe devices 16.

At the ends of the array of devices 16 there are also recesses 50. The openings 46, 48 and the recesses 50 have the function of limiting the structural continuity between the condensation side 20 and the evaporation side 18 only to the areas where this is strictly necessary, thus limiting the heat flow transmissible by conduction between the evaporation side 18 and the condensation side 20 (in this sense they also define a thermal interruption).

With reference also to figures 3, 4, on the basis of an advantageous aspect of the invention, the path of the channels 24, 26, of the connection section 28, of the siphon duct 36 and the tank 16 are made by swelling towards the outside of only one of the sheets S1, S2, in particular sheet S1.

This is because, with reference to Figure 4, for the application considered here it is preferable to have a surface, corresponding to sheet S2, substantially planar for coupling with the photovoltaic layer 2.

It is preferable to have sheet S2 with planar geometry at least in correspondence with the evaporation side 18 of each heat pipe device 16, and again preferably in correspondence with the entire extension of each heat pipe device 16.

As can also be seen in Figure 4, the thermal interruptions 42, 44 preferably pass through and pass through both sheets S1, S2. This also applies if the thermal interruptions are made, for example, by inserts of thermally insulating material.

With reference to Figure 2 and Figures 7 to 10, the manner in which the components of the panel 1 are assembled together will be briefly described.

The heat exchange layer 6 is arranged between the photovoltaic layer 2 and the back panel 8 so that the latter two are on opposite sides with respect to the heat exchange layer 6 and are preferably arranged only in correspondence with the evaporation side of the thermal conduit devices 16 and possibly also in correspondence with the adiabatic zone 22.

In this way, once the layers 2, 6 and the back panel 8 are blocked and packaged by the frame 14, the condensation side 20 of each of the heat pipe devices 16 remains exposed to the outside. It should also be noted that the planar surface of sheet S2 lends itself well to coupling with the surface of photovoltaic cells 4. Such coupling, as will be described below, can be either direct or with an interposed (indirect) element.

The parts in relief on the surface of the sheet S1, on the other hand, come into contact with the back panel 8. As regards the condensation side 20, this is closed between a flange 12, arranged on the sheet S2 and having a shielding function against solar radiation, and the collector element 10, which is fixed on the opposite side of the condensation side 20 in contact and in heat exchange relationship with the tanks 30.

The operation of solar panel 1 is as follows. The solar panel 1 is suitable for installation on a support structure such as, for example, the roof of a building, so that the condensation side 20 of the heat exchange layer 6 has a higher geometric height than the evaporation side 18. This is because each heat pipe device 16 is designed for operation by gravity, ie the heat carrier fluid contained in the closed circuit of each of them circulates mainly under the action of the force of gravity. This further clarifies the meaning of the term â € œgeometric dimensionâ € previously used with reference to tank 30.

Panel 1 is installed so that the photovoltaic layer 2 is directly exposed to solar radiation, so that the back panel 8 is in the shade. When the solar radiation affects the photovoltaic layer 2, the photovoltaic cells 4 transform the energy associated with the solar radiation (at least part of it) into electrical energy which is collected with per se known collector devices. At the same time, the photovoltaic cells 4 undergo heating due to both the incidence of solar radiation and the transformation of the energy received into electrical energy. Based on the preferential methods with which the components of the panel 1 are sized and coupled together (previously described), the photovoltaic cells 4 are coupled to sheet S2 of the heat exchange layer 6 and are applied only in correspondence with the evaporation side 18 of each device 16. The cells 4 can be applied in direct contact with the sheet S2 or can be coupled to it by means of a thin layer of coupling material, which performs the function of anchoring and preventing the creation of hot spots on the cells. photovoltaic 4

In this way the photovoltaic cells 4 transfer a heat flow to the heat exchange layer 6 - in particular to the evaporation side 18 of each device 16 - which powers the operation of the heat pipe devices 16 themselves, creating a temperature difference between the evaporation side 18 and the condensation side 20 and providing the heat necessary for the heat transfer fluid to evaporate in the channel 26, as will now be described.

The first channel 24 of each device 16 is adapted to receive the heat-carrying fluid in liquid phase (by gravity) from the tank 30 through the siphon duct 36, and is able to convey the heat-carrying fluid towards the second channel 26. In particular , when the heat-carrying fluid exits from the tank 30 through the outflow mouth 32, it enters the siphon duct 36 undergoing a re-approach to the tank 30, following the travel of the outflow section 38a, the first loop 38 and the rising section 40a , and a subsequent removal following the passage of the loop 40, after which the fluid is sent towards the channel 24.

Thanks to the presence of the thermal interruptions 42, 44 the conductive heat exchange between the channel 24 of each device 16 and the surrounding material of the sheets S1, S2 is strongly limited. It should be noted that this is very important since if there was not a sufficient barrier against the conductive heat exchange between the channel 24 and the surrounding metal material, there would be a great risk of premature evaporation of heat transfer fluid inside the channel 24, on the contrary, it is intended to house the heat-carrying fluid in the liquid phase and to convey it, possibly always in the liquid phase, towards channel 26.

The heat carrier fluid then enters the second channel 26 in which, thanks to the thermal flow coming from the photovoltaic cells 4, it evaporates and is conveyed in the vapor phase from channel 26 to tank 30. It should be noted that evaporation is favored, among other factors , by the absence of thermal interruptions around channel 26.

The condensation side 20 is in a heat exchange relationship with a fluid, particularly water, which is conveyed inside the duct 11 of the collector element 10.

The water that flows inside the duct 11 absorbs a thermal flow from the heat-carrying fluid in the vapor phase that moves towards and enters each tank 30, causing it to condense and then fall back into the liquid phase towards the bottom of the tank 30 itself, where it find the corresponding siphon duct 36.

In this way, the water flowing inside the duct 11 increases in temperature and can be conveyed outside the manifold 10 for use, for example, as domestic hot water.

The heat transfer fluid inside each of the heat pipe devices 16 therefore goes through a cycle that includes two phase changes, one on the evaporation side 18, the other on the condensation side 20. This process proceeds spontaneously and occurs it repeats cyclically as long as there is an appreciable difference in temperature between the condensation side 20 and the evaporation side 18, in particular the temperature of the latter must be higher.

In this way, in addition to obtaining hot water which can be used elsewhere, cooling of the photovoltaic cells 4 is also obtained by the heat transfer fluid which flows in the closed circuit of each heat pipe device 16, in particular on the evaporation side 18.

It should also be noted that the heat transfer fluid can be, and preferably is, different from water, which eliminates the aluminum corrosion problems mentioned above.

Moreover, thanks to the operation by gravity and to the substantially spontaneous proceeding of the heat transfer fluid cycle, a pump is not necessary to supply the fluid to the cooling system of the cells 4, which in fact is defined by the evaporation side of each device. 16.

In this way, the required power required for the operation of the system is reduced, saving the amount of power destined to drive a coolant pump. Furthermore, the photovoltaic cells 4 can work with higher yields since their operating temperature is mitigated by the heat exchange layer 6.

The substantially split circuit structure of each heat pipe device 16, i.e. comprising a channel for the heat carrier fluid in the liquid phase and a channel for the heat carrier fluid in the vapor phase, also guarantees the absence of problems of entrainment of the heat carrier fluid in phase liquid in the gaseous stream of the same heat-carrying fluid, as there are substantially no interface zones with longitudinal development between the heat-carrying fluid in the liquid phase and the heat-carrying fluid in the vapor phase in any of the channels 24, 26. The only interface zone It is the one where the phase transition takes place on the evaporation side which has a pre-eminently transversal development front with respect to the development of the channels 24, 26.

The presence of the siphon ducts 36 is also very important in order to maintain the controllability of the heat flow transmitted to the outside through the condensation side 20 of each heat pipe device 16. In particular, one of the most frequent problems of known type heat pipe devices is that of the total (or almost total) evaporation of the heat transfer fluid due to an excessive heat flow entering the system.

Thanks to the siphon duct 36, the presence of a certain quantity of heat-carrying fluid in the liquid phase is ensured between the outflow mouth 32 and possibly part of the tank 30 - typically near the bottom of it - and the first loop 38. in this way it is possible to have a certain quantity of fluid trapped partly in the tank 30, partly in the outflow section 38a, partly in the first loop 38 and partly, possibly, in the rising section 40a.

In fact, it should be observed that the operation of the siphon duct 36 is similar to that of a siphon drain for a kitchen sink, in which there is the presence of a certain quantity of liquid in a section of the siphon which is located at a lower than the outflow port, in this case the port 32. In this way, even in conditions of massive heat transfer from the photovoltaic cells 4 it is possible to maintain the controllability of the system and prevent the complete evaporation of the heat transfer fluid, maintaining good performance even under particularly severe conditions of use.

Further help in maintaining the controllability of the heat flow transferred to the outside is also offered by the flange 12, preferably made of thermally insulating material, which offers a shielding action on the condensation side 20 substantially limiting the thermal flow transferred by radiation to the tanks 30.

In the embodiments described, the photovoltaic cells 4 are preferably arranged only in correspondence with the evaporation side of the heat pipe devices 16, since it is in the evaporation side 6 that the heat exchange state should receive heat flow so that the devices at heat pipe 16 work best. In fact, it should be noted that in the case of the arrangement of the photovoltaic layer 2, for example, between the condensation sides 18 and the evaporation sides 20 or in such a way as to cover both sides, as occurs in various devices of known type, numerous non-uniformities would be created in the temperature field on the back of the cells 4 with consequent malfunctions of the system.

Numerous variations and modifications are possible without losing the advantages described here. For example, it is possible to realize the heat exchange layer 6 with split-circuit heat duct devices without a siphon duct 36, therefore closer to a traditional and known solution. It is also possible to realize the thermal conduit devices 16 without the tank 30, thus realizing a system in which the hydraulic capacity is substantially of the distributed type.

It is also possible to vary the route of channels 24, 26 according to needs. In the preferred embodiment described here, the channels 24, 26 have a rectilinear development but embodiments are possible in which, for example, the channel 26 has a serpentine development or in which more than one channel 26 is provided for conveying the heat transfer fluid in the vapor phase towards the condensation side. In fact, it is possible to provide solutions in which the channel 24 forks into a pair (or a set of three and so on) of channels 26 which connect to two (or more) separate inflow outlets on each tank 30. In this case, also the siphon duct between the single channel 24 and the tank 30 can be made in a â € œplurimaâ € form with several outflow openings 16 directly connected to respective outflow sections, therefore to respective first loops, respective rising sections to then have two (or more) second loops that flow into channel 24. In this way, there would be substantially a siphon duct for each channel 26.

In Figure 11, the reference number 106 indicates a further embodiment of the heat exchange layer 6. In the example illustrated here, the heat exchange layer 106 comprises two heat pipe devices 116, but of course it is possible to provide a different number of devices 116, from a minimum of one to a maximum depending on the size of the layer 106.

Each heat conduit device 116 comprises a closed circuit arranged for the circulation of a heat carrier fluid and including an evaporation side and a condensation side of the heat carrier fluid, indicated respectively with reference numbers 118, 120.

Similarly to the previously described embodiment, the heat exchange layer 106 and each device 116 are made by joining a first and a second sheet of metal material S1, S2 with roll bond technology, i.e. joining the sheets S1, S2 in correspondence with the delimiting areas the closed circuit of each device 116, so as to inoculate pressurized air in the regions defining the path of the closed circuit to form the internal volumes of the circuit itself.

An adiabatic zone is provided in correspondence with an interface zone between the evaporation side 118 and the condensation side 120, functionally analogous to the adiabatic zone of the previously described absorber devices, indicated with the reference number 125 and comprising a first and a second thermal interruption 125A, 125B, the first with a straight development, the second with a â € œVâ € geometry. In this way the condensation side has a substantially â € œa stepâ € plan, in which the step is defined by the thermal break with â € œVâ € geometry. It is therefore possible to identify a maximum (longitudinal) extension and a minimum (longitudinal) extension for the condensation side 120, respectively LC, LCâ € ™.

Typical values can be:

- between 1.1 and 3 for LC / LCâ € ™

The thermal interruptions are preferably made by laser cutting, but it is also possible to realize them by means of inserts of thermally insulating material (preferably passing through the sheets S1, S2) or it is possible to provide a combination of both.

The evaporation side 118 comprises a first channel 124 in fluid communication with a plurality of second channels 126 starting from a first collector branch 128. More in detail, the channel 124 is in fluid communication with the collector branch 128 and the channels 126 by means of a first siphon duct 129. The channels 124 and 126 preferably have a straight and parallel development, but other solutions are possible.

With reference to Figure 13, the siphon duct 129 comprises a first and a second loop 129A, 129B arranged fluid-dynamically in series, in which the first loop 129A has a lower geometric height than the second loop 129B.

Preferably, the first loop 129A produces a curve with an amplitude equal to 180 °, while the second loop 129B preferably produces a curve with an amplitude equal to 90 °.

In other words, again with reference to figure 13, the channel 124 flows directly into the loop 129a, which essentially inverses the path of the heat-carrying fluid with respect to the channel 124. The loop 129A therefore flows into the loop 129A. loop 129B, which performs a partial â € œRighteningâ € of the path of the heat-carrying fluid flowing into the manifold branch 128, which therefore preferably has a transverse orientation with respect to the channel 124.

The channels 126 flow into a tank 130 by means of a second collector branch 131. The second collector branch 131 has a transverse orientation (preferably) with respect to the channels 126 (and 124) and in this embodiment it has an increasing passage section proceeding from the channel 126 further. far to channel 126 closer than a common exit 131A.

The connections between the condensation side 120 and the evaporation side 118 will now be better detailed, in particular the connections between the tank 130 and the channels 124, 126.

With reference to Figure 12, the first channel 124 and the second channels 126 are in fluid communication with the tank 130 by means of, respectively, an outflow mouth 132 and an inlet mouth 134, having a higher geometric height than the outflow mouth 132 It should also be noted that the tank 130 has a bottom 130A inclined towards the outflow mouth 132, ie the bottom 130A has a profile which degrades from the inlet mouth 134 towards the mouth 132 so as to favor the outflow of the heat-carrying fluid.

More in detail, the channel 124 is in fluid communication with the mouth 132 by means of a second siphon duct 136, functionally analogous to the previously described siphon ducts, comprising a first and a second loop 138, 140 arranged fluid-dynamically in series. The first and second loops 138, 140 define a double curve path (with essentially â € œSâ € geometry), in which each loop creates a curve with an amplitude preferably equal to 180 °.

Similarly to the siphon ducts described above, the duct 138 comprises an outflow section 138a which starts from the outflow mouth 132 and flows into the first loop 138, and a rising section 140a into which the first loop 138 flows, which in turn flows into the second loop 140, which finally flows directly into channel 124.

It should also be noted that in this embodiment the first loop 138 and the second loop 140 are arranged on opposite sides with respect to the outflow mouth 132, in particular the loop 140 is located above the mouth 132.

Similarly to the embodiments described, called D138 and D140, the distances, respectively, between the tank 130 and the loops 138, 140, preferably the distance D138 is greater than the distance D140, but in this embodiment, given the arrangement of the loops, It is also possible to predict the opposite.

Finally, each channel 124 is bordered by a thermal break 144, preferably having a â € œLâ € shape so as to also border the siphon duct 129, which can be made, for example, by laser cutting or by means of an insert of thermally material. insulating.

Only one of the sheets S1, S2 (in particular the sheet S1) is swollen towards the outside in correspondence with the path of the closed circuit of each device 116, for reasons of optimal coupling with the photovoltaic cells 4.

As regards the operation, there are few variations with respect to the previously described embodiment.

In the closed circuit created by the channels 124, 126, the tank 130 and all the connecting channels between the aforementioned elements, a heat-carrying fluid circulates which undergoes a first phase change on the evaporation side (liquid-vapor) and a second phase passage on the condensation side (vapor-liquid). The hybrid solar panel 1 is installed so that each device 116 is arranged with the tank 130 at a higher geometric height than the rest of the circuit, so that operation takes place essentially by gravity.

Furthermore, the collector element 10 is applied in correspondence with the condensation side 118, as previously described, in particular on the sheet S1 (and on the opposite side the flange 12 is arranged.

The heat transfer fluid leaves the tank 130 in the liquid phase (helped in part by the profile of the bottom 130A) through the outflow mouth 132 and passes through the siphon duct 138, then the first channel 124. The latter is suitable for conveying the heat-carrying fluid towards the first collector branch 128 and towards each of the channels 126. It should be observed that the evaporation of the heat-carrying fluid inside the channel 124 is averted or at least hindered by the thermal interruption 144, which limits the conductive heat exchange with the portions of the surrounding sheets S1, S2.

When the heat-carrying fluid enters the channels 126, the thermal flow dispersed by the photovoltaic cells 4 is transferred to the heat-carrying fluid which evaporates and goes up towards the collector branch 131 and towards the inflow outlet 134, through which it enters the tank 130. Nellâ € ™ the heat transfer fluid condenses through the condensation side 120, transferring heat to the liquid in the collector element 10, which can then be used elsewhere, for example as domestic hot water.

It should be noted that the variable passage section of the branch 131 allows the flow of heat transfer fluid to be disposed of in an optimal way, since it increases as the branch 131 intercepts a channel 126 closer to the outlet 131A.

In this way the non-uniformity of the flow field of the heat carrier fluid inside the circuit is limited.

The cycle then repeats itself during the operation of each device 116, which stops when the temperature difference between the condensation side and the evaporation side is practically zero.

The presence of the siphon ducts 129 and 136 is also very important in order to maintain the controllability of the heat exchanged even under severe operating conditions (ie with strong solar radiation incident on the photovoltaic cells 4). Similarly to the siphon ducts described above, the siphon duct 136 guarantees, thanks to its geometry, the presence of heat-carrying fluid in the liquid phase in a section between the tank 130 and the second loop 140.

The siphon duct 129 also provides a further contribution in terms of maintaining a certain amount of heat transfer fluid in the liquid phase also downstream of the duct 124 and immediately upstream of the ducts 126. In particular, thanks to the siphon duct 129 Ã It is possible to maintain the heat-carrying fluid in the liquid phase at least in the first loop 129A and upstream thereof, that is, in the channel 124.

In alternative embodiments, it is possible to provide for the presence of only the siphon duct 129. The same can also be applied to the previously described closed circuit scheme, with which it is also possible to implement a solution with two distinct siphons of the type described. in figure 11.

Basically, in the various embodiments presented here, each solar absorber device comprises a tank which is in communication with one or more channels designed to convey towards it the thermo-vector fluid in the vapor phase (`` vapor channel / s '') by means of a or more siphon ducts. The one or more steam channels also affect the tank itself through one or more inflow outlets - with respect to which the one or more siphon ducts are fluid-dynamically arranged upstream -.

The aforementioned siphon ducts are arranged upstream of the aforementioned one or more steam channels and can be provided at the outlet of the tank upstream of the channel designed to receive the heat carrier fluid in the liquid phase (â € œLiquid channelâ €) or downstream of it (and upstream of the steam channel (s)) or in both places. In the first case, the siphon duct is connected to the tank outflow mouth and flows into the liquid channel, connecting and communicating with the liquid channel and the tank (without prejudice, of course, to the fluid communication established between the tank and the steam channel (s)).

In the second case, the siphon duct connects and establishes a fluid communication between the liquid channel and the steam channel (s) (possibly through the manifold branch 128, if present), being arranged in correspondence with an interface zone between them.

Naturally, the details of construction and the embodiments may be widely varied with respect to what has been described and illustrated purely by way of example, without thereby departing from the scope of the present invention, as defined by the attached claims.

Claims (10)

CLAIMS 1. Hybrid solar panel (1), comprising: - a photovoltaic layer (2) including a plurality of photovoltaic cells (4), - a heat exchange layer (6; 106) including cooling means for said photovoltaic cells (4), - a collector element (10) arranged to convey a fluid, particularly a liquid, in a heat exchange relationship with said heat exchange layer (6; 106), in which said heat exchange layer (6; 106) comprises one or more heat conduit devices (16; 116) adapted to contain a heat transfer fluid, each heat conduit device (16; 116) comprising: - an evaporation side (18; 118) of said heat-carrying fluid arranged to absorb a flow of heat from said photovoltaic cells (4) and defining said cooling means, - a condensation side (20; 120) of said heat-carrying fluid, in correspondence with which said collector element (10) is applied, said photovoltaic cells (4) of said photovoltaic layer (2) being applied at the evaporation side (18; 118) of said one or more heat conduit devices (16; 116) and being in a heat exchange relationship with them, the solar panel (1) being characterized in that each heat pipe device (16; 116) comprises a closed circuit (24, 26, 28, 30, 36; 124, 126, 128, 130, 136) set up for circulation of said heat-carrying fluid and including a first channel (24; 124) adapted to receive the heat-carrying fluid from said condensation side (20; 120) in the liquid phase and able to convey the heat-carrying fluid towards at least a second channel (26; 126) , said at least one second channel (26; 126) being in turn adapted to convey the heat transfer fluid in the vapor phase towards said condensation side (20; 120), and by the fact that said heat exchange layer (6; 106) is ̈ made by joining a first and a second sheet (S1, S2) of metal material in correspondence with areas delimiting the closed circuit (24, 26, 28, 30, 36; 124, 126, 128, 130, 136) of each heat conduit device (16; 116). 2. Solar panel (1) according to claim 1, characterized in that only the first sheet (S1) of metal material of said heat exchange layer (6; 106) swells towards the outside in correspondence with the circuit path closed (24, 26, 28, 30, 36; 124, 126, 128, 130, 136) of said one or more heat pipe devices (16; 116), said second sheet (S2) of metallic material having a flat surface extending at least in correspondence with the evaporation side (18; 118) of said one or more heat pipe devices (16; 116), preferably along their entire extension, said flat surface being coupled to said photovoltaic cells (4) . Solar panel (1) according to claim 1 or 2, characterized in that the condensation side (20; 120) of each heat pipe device (16; 116) comprises: - a reservoir (30; 130) in fluid communication with said at least one second channel (26; 126) by means of an inlet (32; 132), and - at least one siphon duct (36; 136) through which said tank (30; 130) is in fluid communication with said at least one second channel (26; 126). 4. Solar panel (1) according to claim 3, characterized in that the condensation side (20; 120) of each heat pipe device (16; 116) comprises a siphon pipe (36; 136) arranged upstream of said first channel (24; 124) and connecting said first channel to said outflow mouth (32; 132), said siphon duct (36; 136) comprising a first and a second loop (38, 40; 138, 140) arranged fluid dynamically in series. 5. Solar panel (1) according to claim 4, characterized in that each siphon duct (36; 136) further comprises: - an outflow section (38a; 138a) connected to said outflow mouth (32; 132) and leading into said first loop (38; 138), and - an upward stretch (40a; 140a) into which said first loop (38; 138) flows, said upward stretch (40a; 140a) leading in turn to said second loop (40; 140), which flows into said first channel (24; 124). 6. Solar panel (1) according to claim 4, characterized in that the evaporation side (118) of each heat pipe device (116) comprises a further siphon pipe (129) arranged downstream of said first channel (124 ) at an interface between said first and at least one second channel (124, 126). 7. Solar panel (1) according to claim 3, characterized in that said condensation side (20; 120) is coupled to said collector element (10) in correspondence with the tank (30; 130) of each of said one or multiple heat pipe devices (16; 116). 8. Solar panel (1) according to any one of the preceding claims, characterized in that said heat exchange layer (6; 106) comprises an adiabatic zone (22; 125) at an interface between said evaporation side ( 18; 118) and said condensation side (20; 120) of each of said one or more heat pipe devices (16; 116), wherein said adiabatic zone (22; 125) comprises a plurality of thermal interruptions. Solar panel (1) according to any one of the preceding claims, characterized in that it further comprises a back panel (8) arranged in contact with said first sheet (S1) of metal material on an opposite side with respect to said photovoltaic layer (2 ), in which said solar panel (1) further comprises a frame (14) designed to pack together said photovoltaic layer (2), said heat exchange layer (6; 106) and said back panel (8). 10. Solar panel (1) according to any one of the preceding claims, characterized in that the first channel (24; 124) of each heat pipe device (16; 116) is bordered by a first and a second thermal interruption (42 , 44; 144) comprising: - interruptions made by laser cutting, - inserts of thermally insulating material, or - a combination of them.