A SOLAR COLLECTOR PANEL AND A METHOD FOR OPERATING A SOLAR COLLECTOR PANEL

Abstract

Disclosed is a solar collector panel (1) configured for collecting thermal energy by heating of air. The solar collector panel (1) comprises an air conduit (2) for guiding air through the panel (1) between an air inlet (3) and an air outlet (4) and the panel (1) comprises air flow means (5) arranged to generate an air flow through the air conduit (2) from the air inlet (3) to the air outlet (4). The panel (1) further comprises light absorbing means (6) arranged in or at the air conduit (2) to heat passing air and air drying means (7) arranged between the air inlet (3) and the light absorbing means (6), wherein the air drying means (7) is arranged to reduce the absolute humidity of passing air. A method for operating a solar collector panel (1) is also disclosed.

Claims

1. A solar collector panel (1) configured for collecting thermal energy by heating of air, said solar collector panel (1) comprising an air conduit (2) for guiding air through said panel (1) between an air inlet (3) and an air outlet (4), air flow means (5) arranged to generate an air flow through said air conduit (2) from said air inlet (3) to said air outlet (4), light absorbing means (6) arranged in or at said air conduit (2) to heat passing air, and air drying means (7) arranged between said air inlet (3) and said light absorbing means (6) wherein said air drying means (7) is arranged to reduce the absolute humidity of passing air.

2. A solar collector panel (1) according to claim 1, wherein said air drying means (7) comprises a desiccant.

3. A solar collector panel (1) according to claim 1 or 2, wherein said solar collector panel (1) comprises reversing means (8) for at least occasionally reversing the air flow through said panel (1).

4. A solar collector panel (1) according to claim 3, wherein said reversing means (8) is at least a part of said air flow means (5).

5. A solar collector panel (1) according to claim 3 or 4, wherein said panel (1) further comprises a reversed flow air inlet (9) through which air is drawn when said air flow is reversed.

6. A solar collector panel (1) according to any of the preceding claims, wherein said panel (1) further comprises one or more humidity sensors (10).

7. A solar collector panel (1) according to claims 3 and 6, wherein said panel (1) comprises control means (11) arranged to activate said reversing means (8) on the basis of input from said one or more humidity sensors (10).

8. A solar collector panel (1) according to any of the preceding claims, wherein said air drying means (7) is arranged in a separate container (12) in or on said solar collector panel (1).

9. A solar collector panel (1) according to claim 8, wherein said separate container (12) is detachably connected to said solar collector panel (1).

10. A solar collector panel (1) according to any of the preceding claims, wherein said air drying means (7) further comprises air cleaning means.

11. A solar collector panel (1) according to any of the preceding claims, wherein said air inlet (3) is arranged separate from said air outlet (4).

12. A solar collector panel (1) according to any of the preceding claims, wherein said air drying means (7) are arranged between said air inlet (3) and said light absorbing means (6) inside said solar collector panel (1).

13. A solar collector panel (1) according to any of the preceding claims, wherein said air drying means (7) are arranged parallel with or at least substantially parallel with said light absorbing means (6).

14. A solar collector panel (1) according to any of the preceding claims, wherein the effective area of said air drying means (7) is equivalent to or at least substantially equivalent to the effective area of said light absorbing means (6).

15. A solar collector panel (1) according to any of the preceding claims, wherein said air drying means (7) extends substantially along the entire back plate (16) of said solar collector panel (1).

16. A solar collector panel (1) according to any of the preceding claims, wherein said solar collector panel (1) comprises a transparent or translucent front plate (14).

17. A method for operating a solar collector panel (1), said method comprising the steps of: generating an air flow through air drying means (7) of said solar collector panel (1) to reduce the absolute humidity of the air passing through said air drying means (7), where after the air is led passed or through light absorbing means (6) to heat said air, and at least occasionally reversing the air flow direction so that the air is first led by said light absorbing means (6) and then through said air drying means (7).

18. A method according to claim 17, wherein said air flow is reversed when the air drying quality of said air drying means (7) has dropped below a predefined level.

19. A method according to claim 17 or 18, wherein said reversed air flow is drawn in through a dedicated reversed flow air inlet (9).

20. A method according to any of claims 17-19, wherein said method is a method for operating a solar collector panel (1) according to any of claims 1-16.

Description

FIGURES

[0049] The invention will be described in the following with reference to the figures in which

[0050] FIG. 1 illustrates a first embodiment of a solar collector panel during normal operation, as seen from the side,

[0051] FIG. 2 illustrates the solar collector panel of FIG. 1 with a reversed air flow, as seen from the side,

[0052] FIG. 3 illustrates a second embodiment of a solar collector panel during normal operation, as seen from the side,

[0053] FIG. 4 illustrates the solar collector panel of FIG. 3 with a reversed air flow, as seen from the side, and

[0054] FIG. 5 illustrates a solar collector panel with a separate reversed flow air inlet, as seen from the side.

DETAILED DESCRIPTION OF THE INVENTION

[0055] FIG. 1 illustrates a first embodiment of a solar collector panel during normal operation, as seen from the side.

[0056] In this embodiment the solar collector panel 1 comprises an air inlet 3 arranged at the bottom of the panel 1 and an air outlet 4 arranged at the back of the panel 1 so that if the panel 1 is mounted on a sloping roof surface or on the side of a building the heated air can be exhausted more or less directly into the building through the mounting surface at the back of the panel 1.

[0057] The present solar collector panel 1 is shown during normal operation where air flow means 5 in the form of a fan arranged at the air outlet 4 draws air into the panel 1 through the air inlet 3 and further through air drying means 7 to reduce the absolute humidity of the air. After the air drying means 7 the air continues down past the light absorbing means 6 which in this embodiment comprises a metal plate painted black. The light absorbing means 6 absorbs the radiation from the sun (illustrated by the curvy arrows) which will heat up the heat absorber plate 6. The large surface of the light absorbing means 6 ensures that this heat is efficiently dissipated to the passing air—thus heating the air before it is exhausted out through the air outlet 4.

[0058] To protect the inner components of the panel 1 and to increase the efficiency of the panel 1 the front plate 14 of the panel 1 is transparent or translucent. In this embodiment the front plate 14 is made from polycarbonate but in another embodiment it could be made from glass, another plastic material, a composite material or other.

[0059] In this embodiment the air flow means 5 is powered by a solar cell 15 having a photovoltaic side which is substantially orientated in the same direction as the front plate 14. However, in another embodiment the air flow means 5 could be powered by a battery, by an external power source or other.

[0060] In this embodiment the solar cell 15 is mounted on the outside of the front plate 14 but in another embodiment the solar cell 15 could be mounted on the inside of the front plate 14, on or at the light absorbing means 6 or anywhere else on, in or at the solar collector panel 1.

[0061] In all the embodiments disclosed in FIGS. 1-5 the air flow means 5 are in the form of a motor driven fan but in another embodiment the air flow means 5 could be a specific panel design utilizing a chimney-effect to create self-circulation or the air flow means 5 could be formed by a pump or other means suited for displacing air.

[0062] FIG. 2 illustrates the solar collector panel 1 of FIG. 1 with a reversed air flow, as seen from the side.

[0063] As the air drying means 7 absorbs moisture from the passing air the moisture absorbing property of the air drying means 7 is reduced so in this embodiment the panel 1 is provided with reversing means 8 in that the rotational direction of the air flow means 5 is changed (by control means 11), so that the air flow means 5 instead of drawing air out of the panel 1, pushes air into the panel 1 so that the air first is heated by the light absorbing means 6 before it passes through the air drying means 7. Hereby humidity from the air drying means 7 is released to the passing air and transported out into the surroundings. The air drying means 7 is thus regenerated and will now function efficiently again as a dehumidifier when normal operation is resumed.

[0064] In this embodiment the panel 1 is provided with a humidity sensor 10 arranged at the air inlet 3 and a humidity sensor 10 arranged at the air outlet 4. These humidity sensors 10 deliver data to control means 11—e.g. in the form of a small PLC, PC, logic circuit or other. The control means 11 will then control the operation of the air flow means 5 at least partly in response to output from these humidity sensors 10. In a preferred embodiment the humidity sensors 10 are supplement with temperature sensors (not shown) in that based on information of the humidity and temperature of both the incoming and the exhausted air it is possible to exactly calculate the absolute humidity of the incoming and the exhausted air. Thus, if these are compared a more or less exact status of the efficiency of the air drying means 7 can be derived.

[0065] The invention is e.g. particularly advantageous in relation with tropical climate zones with high humidity where it can be used for producing relatively dry air to prevent mould etc. in buildings and to dry crops and plants.

[0066] In the embodiments disclosed in FIGS. 1-4 the reversing means 8 are incorporated in the air flow means 5 but in another embodiment of the invention the reversing means 8 would be a separate fan—or another air flow generating device—arranged to generate an air flow in the opposite direction than the air flow means 5.

[0067] FIG. 3 illustrates a second embodiment of a solar collector panel 1 during normal operation, as seen from the side, and FIG. 4 illustrates the solar collector panel 1 of FIG. 3 with a reversed air flow, as seen from the side.

[0068] In this embodiment the panel 1 is provided with a perforated back plate 16 so that the air inlet 3 is distributed throughout this back plate 16 and in this embodiment the air drying means 7 is arranged outside this back plate 16 so that the air first have to pass through the air drying means 7 before it is drawn into the panel 1 to be heated by passing the light absorbing means 6 arranged on the inside of the back plate 16.

[0069] When the reversing means 8 is activated—as disclosed in FIG. 4—the air is first heated before it is pushed out through the perforated back plate 16 and further on through the air drying means 7.

[0070] Arranging the air drying means 7 at the back of the panel 1 is advantageous in that the air drying means 7 can be cooled by the surroundings and in that the air drying means 7 are easy to access.

[0071] In this embodiment the air drying means 7 are arranged in a separate container 12 which is detachably connected to the back plate 16 of solar collector panel 1 so that the air drying means 7 easily may be replaced, repaired or other. In this embodiment the separate container 12 is a box formed by wire mesh enabling that air can easily pass through the container 12. However, in another embodiment the air drying means 7 could be formed with a rigid—albeit porous—structure so that the container 12 could be avoided.

[0072] In this embodiment the air drying means 7 are silica gel (SiO2) but in another embodiment the air drying means 7 could instead or also comprise a number of other known desiccants and/or the air drying means 7 could also comprise additives or other to clean the air, to remove unwanted odour or other.

[0073] In this embodiment the solar panel 1 is provided with a humidity sensor 10 in direct contact with the air drying means 7 so that the operation of the air flow means 5 is controlled in response to a direct measurement of the humidity in the air drying means 7. This could e.g. be done by measuring the electrical resistance over a part of air drying means 7 or in a number of other ways.

[0074] FIG. 5 illustrates a solar collector panel 1 with a separate reversed flow air inlet 9, as seen from the side.

[0075] In this embodiment the panel 1 further comprises a reversed flow air inlet 9 so that when the air flow direction through the panel 1 is reveres—to dry the air drying means 7—the air is drawn in through this dedicated reversed flow air inlet 9 instead of in through the air outlet 4.

[0076] Before the reversing means is activated—as they have been in FIG. 5—the air flow means 5 is first shut down before a valve 17 in the air outlet 4 is shut by means of a valve actuator 18. Separate reversing means 8—in this case in the form of a fan 5 located in the reversed flow air inlet 9—will now be activated whereby it will generate an air flow which will open a non-return valve 18 in the reversed flow air inlet 9 so that air is now drawn from the surrounding (through the reversed flow air inlet 9) instead of from the room to which the hot air is exhausted during normal operation of the panel 1.

[0077] All these operations are in this embodiment controlled by the control means 11 and powered by the solar cell 15.

[0078] In all the embodiments disclosed in FIGS. 1-5 the air drying means 7 are arranged in a shady part of the panel 1 i.e. at the back of the panel 1, behind the light absorbing means 6 or other. This is advantageous in that the moisture absorbing quality of desiccants is at least to some degree temperature dependent—i.e. the colder the desiccant is, the more moisture it can absorb.

[0079] FIGS. 1, 3, and 5 discloses different designs of the solar collector panel 1 capable of heating and moving air entirely by means of energy provided from the sun but in another embodiment the solar collector panel 1 could be designed differently it could comprise further and/or other components and/or the components could be arranged differently.

[0080] The invention has been exemplified above with reference to specific examples of designs and embodiments of solar collector panels 1, air flow means 5, air drying means 7 etc. However, it should be understood that the invention is not limited to the particular examples described above but may be designed and altered in a multitude of varieties within the scope of the invention as specified in the claims.

LIST

[0081] 1. Solar collector panel [0082] 2. Conduit [0083] 3. Air inlet [0084] 4. Air outlet [0085] 5. Air flow means [0086] 6. Light absorbing means [0087] 7. Air drying means [0088] 8. Reversing means [0089] 9. Reversed flow air inlet [0090] 10. Humidity sensor [0091] 11. Control means [0092] 12. Container for air drying means [0093] 13. Non-return valve [0094] 14. Front plate [0095] 15. Solar cell [0096] 16. Back plate [0097] 17. Valve [0098] 18. Valve actuator