EP2352955A2

EP2352955A2 - Solar pot

Info

Publication number: EP2352955A2
Application number: EP09771774A
Authority: EP
Inventors: Daniele Lauri
Original assignee: SUNERG SOLAR Srl
Current assignee: SUNERG SOLAR Srl
Priority date: 2008-12-05
Filing date: 2009-11-11
Publication date: 2011-08-10
Also published as: IT1391995B1; WO2010064102A3; WO2010064102A2; CN102227597A; ITAN20080059A1; WO2010064102A8

Abstract

The object of the present invention is a therma solar system (1; 1 ') comprising at least one solar panel (2; 2') inside which a fluid runs heated by the incident solar radiation, and a storage tank (3), directly connected to it via known means, suitable for containing the domestic water for the users. The storage tank (3) is fitted inside a container (4; 4'), for example an ordinary pot for the composition of flowers and/or ornamental plants.

Description

SOLAR POT

DESCRIPTION

The object of the present invention is a thermal solar system for civil or industrial buildings.

More in particular, the object of the invention is a particular method of installation of a solar panel and relative storage tank for the production of domestic hot water. The invention therefore relates to the field of use of solar energy for the production of domestic hot water, a continuously growing field especially in Mediterranean countries, thanks to the advantageous weather conditions, but also in countries with unfavourable weather conditions, such as Germany, that have long encouraged such environment- friendly energy systems through a tax relief and advantage policy. Solar panels for the production of domestic hot water are known.

The most widespread solar panel in civil systems is the flat-glazed panel, consisting of:

- a transparent cover, composed of one or more glass sheets that let the incoming solar radiations pass through and block the outgoing ones;

- an underlying absorbing plate that absorbs the radiation and transfers the energy gathered to the heat transfer fluid (usually antifreeze fluid, such as for example propylenglycol);

- channels in thermal contact with said absorbing plate, wherein the heat transfer fluid subject to heating runs;

- heat insulating material for all parts not exposed to the solar radiation and optionally outer casing for protecting the above components and limiting heat losses of the panel. In solar heating panels, solar panels are connected through a hydraulic circuit to a storage tank for domestic water and for room heating.

The circulation of the heat transfer fluid, which carries the thermal energy captured by the solar panel to the storage tank, may be of the natural or forced type. Natural circulation occurs without the aid of pumps, simply actuated by the thermosiphon effect of the heat transfer fluid that, heating inside the panel, becomes lighter (reducing its density) and moves upwards by convection towards the storage tank, exchanges heat with the fluid contained therein and cooling down, returns downwards. Therefore, for a similar natural circulation to occur, the storage tank must be placed higher than the panel, a device only possible in small sized systems and in places wherein there is enough space for such arrangement.

On the other hand, forced circulation takes place with the aid of one or more circulation pumps and of course in this case there are no constraints for the location of the storage tank. The drawbacks found in a natural circulation system therefore are not found, but there are drawbacks related to the higher cost required for the pump and the control board and for their maintenance.

A second type of panels are the so-called solar panels with vacuum tubes, hereinafter called "vacuum panels", preferably used in places and/or zones with low external temperatures. Vacuum panels are well-known devices that therefore are briefly described at least for clarifying the terminology that shall be used hereinafter. According to a widely used type, the vacuum panel comprises at least one plate absorbing the solar energy, called "absorber", placed internally and protected by a transparent tubular element, called "vacuum tube", wherein a vacuum is made that is sufficiently strong to minimise the heat losses by convection and conduction. The absorber is of the so-called "selective" type, suitable for absorbing the solar radiation in the visible spectrum, and for emitting very little radiation in the thermal infrared spectrum. These solutions allow obtaining very efficient vacuum panels in the conversion of the incident solar radiation in thermal energy. However, in order to obtain a vacuum panel of even higher efficiency, it is also necessary to efficiently remove the thermal energy produced in the absorber. For this reason, the vacuum panels with "heat pipes", which use the heat transfer properties associated to the phase change of particular substances, have become widespread. The heat pipe therefore is, as known, a very effective device in transferring the thermal energy. It substantially is a conduit, placed inside the vacuum tube, wherein a low boiling point fluid, hereinafter called "carrying fluid", is contained, subject to evaporating, even at low temperatures in a zone called "evaporator", where thermal energy is administered thereto. The vapour that develops following the fluid heating (by the effect of the incident solar radiation) moves up towards the top end of the conduit that ends with a condensation heat exchanger: the latent vapour heat, released by condensation, is then transferred through suitable heat exchange surfaces, to the water contained in the storage tank, wherein said exchanger is immersed. The fluid condensed therein returns by gravity to the evaporator.

More in particular, in heat pipes, the evaporator consists in all the conduit portion thermally connected to the absorber, whereas the condenser is a bulb in thermal contact, as seen, with the water of the storage tank, through suitable exchange surfaces.

A common deterrent for making a solar system is often related to the difficulty of positioning the panel, whatever type it is, and the relative storage tank on the roof, both for logistic and aesthetic reasons of the buildings. Moreover, especially in less recent buildings and in those wherein it is more difficult to carry out the works required for a solar system, above all for structural reasons, there is often the need of placing the storage tank in rooms even quite far away from the relative solar panel. In these conditions therefore, the solar circuits are much wider and more complex than what is ideal and such as to cause a considerable increase of costs (suffice it to mention the pumps for forced circulation), heat losses and relative reduction in the energy efficiency. The object of the present invention is to eliminate at least part of the logistic, structural and aesthetic problems described above.

More precisely, the object of the present invention is to enable the installation of solar systems also in relatively small and narrow spaces and with a low visual impact. A further object of the present invention is to improve and simplify the make of the solar system circuit, that is, of the hydraulic connections between the solar panel and the storage tank.

These and other objects, which shall appear clearly hereinafter, are achieved with a solar heating system according to claim 1.

Other advantages may be further achieved by the additional features of the dependent claims.

Further features of the present finding will appear more clearly from the following description of some preferred embodiments thereof, according to the patent claims and illustrated, by way of a non-limiting example, in the annexed drawings, wherein:

- figure 1 shows a perspective partially cross-section view of the solar heating system according to the invention;

- figure 2 shows a perspective totally cross-section view of the solar heating system according to the invention;

- figure 3 shows a detail of figure 1 and 2;

- figure 4 shows two perspective views of the same solar heating system and of the support frame thereof according to the invention;

- figures 5a and 5b show a perspective view of a connection in series and of a parallel connection, respectively, of two or more solar heating systems according to the invention.

The features of the finding shall now be described using the references contained in the figures.

With particular reference to figure 1, reference numeral 1 indicates the solar heating system as a whole also called "solar pot" 1 for the reasons that will be readily understood in the description.

As known, the solar heating system 1 comprises a solar panel 2 inside which a heat transfer fluid runs heated by the incident solar radiation, and a horizontal storage tank 3, connected to it via known means, suitable for storing the thermal energy provided by the heat transfer fluid itself. Hereinafter, for description simplicity, the storage tank 3 will be referred to as

"storage".

With reference to figure 1 or 2, storage 3 is located at a higher height than that of solar , panel 2 but in the immediate vicinity thereof, so as to be reached by natural circulation by the heat transfer fluid coming from the underlying solar panel 2.

As known, the heat stored in storage 3 is suitable for feeding a system for distributing domestic hot water.

Storage 3 is therefore provided with an inlet pipe 301 for introducing, in the low part, the water to be heated, and with an outlet pipe 302 for drawing off, from the high part, the domestic hot water for the users.

Preferably, but not necessarily, storage 3 may further comprise a pit 303 for inserting a probe intended for sensing the domestic water temperature at the drawing zone.

According to the invention, storage 3, with the features briefly described above, is located inside a container 4, preferably of plastic material, that hides it to the sight; as a consequence, panel 2 connected to it substantially extends underneath said container 4.

More in particular, container 4 is an ordinary pot, with a rectangular base, for the composition of flowers and ornamental plants 5, both genuine and artificial.

As is usual, pot 4 may be positioned and hooked to balustrades of balconies or to a facade of a building (more in general, therefore, to any substantially vertical element of a building) by means of a frame 6, described in detail hereinafter; for the moment, it is sufficient to say that said frame 6 is suitably moulded and shaped for withstanding the weight of pot 4, of storage 3, contained therein, and of solar panel 2, ensuring seat and support thereof. Storage 3 and the relative solar panel 2 may be installed with simplicity on any facade of a building by means of pot 4 and frame 6, instead of being placed tilted on the roof of a building.

In particular, solar panel 2 is positioned substantially vertical on such facade, whereas storage 3, hidden to the sight, preserves the architectural appearance thereof. Preferably, said solar heating system 1 is positioned on balustrades of balconies or close to windowsills of building facades facing south-east, south-west.

According to the preferred embodiment of the invention of figure 1 or 2, solar panel 2 consists of a series of sealed vacuum tubes 201 therein comprising heat pipes 202 according to the prior art. As known and mentioned already, heat pipes 202 contain a heat transfer fluid subject to vaporising almost instantly under the action of the heat absorbed by an absorber and of condensing at a bulb 203, placed at the head thereof.

As per prior art, bulb 203 is seated in special cylindrical cavities 304 (see for example figure 3) obtained in storage 3, wherethrough the latent condensation heat is transferred to the water to be heated introduced therein through the inlet pipe 301.

The water thus heated is then drawn off and delivered to the domestic hot water distribution network through said outlet pipe 302.

A series of openings, with substantially circular section, is therefore provided on pot 4 intended, as said, for seating storage 3, for allowing at least the passage of the inlet 301 and outlet 302 pipes of the domestic water and of the vacuum tubes 201 of the solar panel 2.

In particular, the hole for the passage of the inlet pipe 301 of cold water in storage 3 is obtained on side 401 of pot 4, whereas a first passage for the outlet pipe 302 of the domestic hot water and optionally a second passage for seating the probe holder pit 303 are respectively obtained on side 402. On the other hand, a series of openings for the insertion and passage of the vacuum tubes

201 that as seen, fit into storage 3, is obtained on bottom 403 of pot 4.

Of course, the number of openings of bottom 403 of pot 3 is equal to the number of vacuum tubes 201 making up the solar panel 2.

As shown in figure 1, reference numeral 7 finally indicates an insulation positioned between shell 305 of the storage tank 3 and the inner walls of pot 4 in order to contain the unavoidable heat losses.

According to a preferred embodiment of the invention, insulation 7 is a polyurethane foam that fills all the volume, inside pot 4, not occupied by the storage tank 3 and by the top ends of each vacuum tube 201 connected thereto. Reproductions of flowers and/or ornamental plants, such as those of plastic material easily found on the market, may be fixed to the top visible surface of insulation 7.

However, nothing prevents the possibility of continuing to grow genuine flowers and/or ornamental plants in pot 4.

In fact, it is sufficient to leave a sufficient volume between the top surface of insulation 7 and edge 404 of pot 4 for seating a layer of soil suitable for the survival and growth thereof.

At this point, it is possible to move to the description of frame 6 suitable, as mentioned, for supporting the solar heating system 1 to the balconies and windowsills railings.

As shown in figure 4, frame 6 comprises a first top back 601, connected to a second bottom back 602 through a connecting surface 603.

Reference numeral 604 indicates a suitably shaped means for fixing frame 6 to a support, for example the handrail of a balustrade of a balcony.

According to a first embodiment of the invention (and with no limiting purpose), said fixing means 604 is placed at the top of the first back 601 and the edge 404 of pot 4 can rest thereon, ensuring the support thereof.

On the other hand, back 602 ends at the bottom end with a support 605 for the solar panel

2, in particular for supporting the vacuum tubes 201 thereof and keeping them in operating position.

For higher precision, the first back 601 has an inclination substantially coincident with that of the back wall 405 of pot 4 it connects with, whereas the second back 602 lies on a plane substantially parallel to that vertical of the solar panel 2.

The connecting surface 603 finally lies on a plane substantially orthogonal to that of the first 601 and second 602 back.

While it is not shown in the annexed figures, on the front face 6O2.a of back 602 it is possible to apply a reflecting film for concentrating a high amount of sun rays on the solar panel 2 itself, thus optimising the yield thereof.

It is also possible to provide a grate (not shown), fixed by known means to frame 6, for protecting the solar panel 2 from collisions of objects and/or birds.

Frame 6 has been described according to a first embodiment but it is clear that several other equivalent versions are possible.

By way of an example only and therefore with no limiting purpose, pot 4 of the solar heating system 1 has a standard width of about 100 cm, a height of about 44 cm and a depth preferably of 38 cm.

The horizontal storage 3 contained in such pot 4 has a capacity of 40 liters and preferably has a length of 80 cm and a diameter of about 26.5 cm. As regards the solar panel 2, with no limiting purpose, the vacuum tubes 201 preferably have a length of 60 cm and an outer diameter of about 6 cm.

A solar pot 1 thus shaped and sized provides domestic hot water capable of substantially meeting the daily requirements of a person. In any case, it is possible to meet the daily consumption of domestic hot water, in terms of temperature and/or flow rate, of a larger number of people (for example a family) by simply connecting in a series or in parallel, according to the needs, two or more solar heating systems 1 according to the invention. For example, figure 5a shows a connection in series of two solar heating systems 1 to be made when the output temperature is preferred over efficiency, the flow rate being the same; nothing prevents the possibility of connecting even more than two in a series, preferably up to a maximum of six.

According to this connection, the outlet pipe 302 of domestic hot water from storage 3 of the first pot 4 is connected, through a conduit portion 9, to the inlet pipe 301' of storage 3 ofthe next pot 4'.

In this way, as known, it is possible to raise the domestic hot water temperature intended for the users, in consecutive steps.

Moreover, a connection in parallel of two or more solar heating systems 1 is also possible, especially if, as known, larger rates of domestic hot water are required but not at very high temperatures.

With reference to figure 5b, the inlet pipe 301 in storage 3 of the first solar heating system 1 is therefore divided into a first portion 301. a suitable for feeding storage 3 of said first solar system 1, and into a second portion 30 Lb for feeding the next solar system 1', bypassing the first one. Likewise, the outlet pipe 302 of the domestic water heated in the first solar heating system 1 by-passes the next solar system 1', directly flowing into the outlet pipe 302' thereof. In the case of connection in parallel of two or more solar pots 1 , said inlet and/or outlet pipes 301, 301. a, 30Lb and 302, 302' are placed as adjacent the bottom 403 and/or the back wall 405 of pot 4 as possible so as to hide them to the sight. The same frame 6 supporting the solar pots 1 and for hooking to the railings of balconies and/or windowsills may be provided with special aesthetic covers (not shown) for hiding said pipes 301, 301. a, 30 Lb and 302, 302' to the sight.

While not shown in figure 5b, moreover, it is possible to envisage the use of valves suitable for cutting off said portion 301. a and/or 301.b in the case, for example, of maintenance or replacement of the one or the other solar heating system 1.

It is clear that several versions of the solar heating system 1 object of the invention are possible to the man skilled in the art, without departing from the novelty scopes of the inventive idea, as well as it is clear that in the practical embodiment of the invention the various components described above may be replaced with technically equivalent ones. For example, nothing prevents the solar panel 2, rather than being of the type with vacuum tubes 201, from being a flat-glazed panel, especially in the case a containment of costs is preferred over higher performances.

According to this version (not shown), the flat-glazed panel, placed vertically under pot 4, is connected to a heat exchanger placed inside or outside storage 3 of pot 4; through said exchanger, the heat transfer fluid coming by natural circulation from the underlying glazed panel transfers the heat absorbed to the water of storage 3.

According to this version, it is therefore necessary to provide further openings on sides 401 and 402 of pot 4 for the insertion and passage respectively of the delivery conduit that connects the glazed panel to said exchanger and the return conduit of the cold heat transfer fluid from the same exchanger to the glazed panel.

Preferably, said heat exchanger is a double-walled heat exchanger.

According to another version of the invention, instead of envisaging the presence of a heat exchanger 203 inside (in the case, for example, of the heat pipe bulb) or outside (the double wall of the first version of the invention) of storage 3 and thus a so-called indirect heating of the water contained therein (by means of the heat transferred through said exchanger by the heat transfer fluid heated in the solar panel), as an alternative, a so-called direct heating is possible with the same water of storage 3 circulating and heated directly in the solar panel 2. Finally, it is possible to also envisage a forced circulation of the heat transfer fluid (or of the same water of storage 3) from the solar panel 2 to the heat exchanger (or directly to storage 3). According to this further version, consequently, the solar panel 2 may be placed at great distance from storage 3 contained in pot 4.

From the above description it is easy to note that a first order of advantages of the solar heating system 1 of the invention consists in the integration of the traditional components of a solar system in a compact shape that therefore allows said system 1 to be installed in any building, even in small and narrow spaces.

A second order of advantages, moreover, can be found in the architectural integration of said thermal solar system 1, that fully simulates the appearance of a pot for growing flowers and/or ornamental plants, and which can therefore easily harmonise with the remainder of the building without defacing the aesthetics thereof.

Claims

CIm. 1 Thermal solar system (1; 1 ') comprising:

- at least one solar panel (2; 2') inside which a fluid runs heated by the incident solar radiation, - and a storage tank (3), directly connected to it via known means, suitable for containing domestic water and in turn comprising at least,

- one pipe (301 ; 301.a, 301.b) for inlet of the cold water,

- one pipe (302; 302') for drawing off the hot water for the users, the water contained in said storage tank (3) being heated by circulation of said fluid coming from said at least one solar panel (2; 2'), characterised in that said storage tank (3) is fitted inside a container (4; 4'), said container (4; 4') being an ordinary pot for the composition of flowers and/or ornamental plants. CIm. 2 Thermal solar system (1 ; 1 ') according to the previous claim characterised in that said solar panel (2; 2') is positioned immediately below said pot (4; 4') containing said storage tank (3), said storage tank (3) therefore being reached by natural circulation of said fluid coming from the solar panel below (2; 2'). CIm. 3 Thermal solar system (1 ; 1 ') according to the previous claim characterised in that said solar panel (2; 2') is positioned vertically.

CIm. 4 Thermal solar heating system (1 ; 1 ') according to any previous claim characterised in that it furthermore comprises an insulation (7) positioned inside said pot (4; 4'), said insulation (7) filling all the volume not occupied by said storage tank (3), limiting the heat loss thereof.

CIm. 5 Thermal solar system (1 ; 1 ') according to any previous claim characterised in that said solar panel (2; 2') is a panel with vacuum tubes (201 ; 201 '). CIm. 6 Thermal solar system (1 ; 1 ') according to any claim from 1 to 4 characterised in that said solar panel (2; 2') is a solar flat-glazed panel. CIm. 7 Thermal solar heating system (1 ; 1 ') according to claim 5 or 6 characterised in that the fluid which runs inside said solar panel (2; 2') is the water contained in said storage tank (3), thus providing direct heating of the same. CIm. 8 Thermal solar system (1; 1 ') according to claim 5 or 6 characterised in that the fluid which runs inside said solar panel (2; 2') is a heat-transfer fluid, said heat-transfer fluid releasing the heat absorbed to the water contained in said storage tank (3) by means of a heat exchanger (203), thus providing indirect heating of said water. CIm. 9 Thermal solar system (1, 1 ') according to the previous claim characterised in that said heat exchanger (203) is a double- walled heat exchanger.

CIm. 10 Thermal solar system (1; 1 ') according to claim 5 characterised in that said vacuum tubes (201; 201') are of the type containing heat pipes (202). CIm. 11 Thermal solar system (1 ; 1 ') according to the previous claim characterised in that said heat pipes (202) comprise, in correspondence of their head, a bulb (203), said bulb (203) acting as a heat exchanger for heating the water contained in said storage tank (3).

CIm. 12 Thermal solar system (1; 1 ') according to the previous claim characterised in that each bulb (203) is inserted in a corresponding cylindrical cavity (304) obtained on said storage tank (3). CIm. 13 Thermal solar system (1 ; 1 ') according to any previous claim characterised in that it is positioned and hooked to a substantially vertical element of a building, such as a balustrade of a balcony and/or of a windowsill, or a facade. CIm. 14 Frame (6) for the solar heating system (1; 1') of claims 1 to 13 characterised in that it supports and constrains said pot (4; 4') and said solar panel (2; 2'), connected to it, to a balustrade of a balcony and/or of a windowsill, or to a facade of a building. CIm. 15 Frame (6) according to the previous claim characterised in that it comprises a reflecting surface (6O2.a). CIm. 16 Frame (6) according to the claim 14 or 15 characterised in that it comprises a protective grating for said solar panel (2; 2'). CIm. 17 Thermal solar plant for the production of domestic hot water comprising one or more solar heating systems (1; 1') as described in the previous claims connected in series and/or in parallel to each other.