WO2014080399A1

WO2014080399A1 - Naturally-irrigated solar panel and solar collector cleaning system

Info

Publication number: WO2014080399A1
Application number: PCT/IL2013/050954
Authority: WO
Inventors: Eran FISCHER
Original assignee: Fischer Eran
Priority date: 2012-11-26
Filing date: 2013-11-19
Publication date: 2014-05-30

Abstract

A naturally-irrigated cleaning add-on for a solar panel or a solar collector, comprising: at least one wiper track mountable on at least one side, respectively, of a frame of said solar panel or said solar collector; a wiping unit configured to travel along said at least one wiper track, to clean a transparent front cover of said solar panel or said solar collector; and an automatic actuator configured to actuate said wiping unit upon detection of dew and/or precipitation.

Description

NATURALLY-IRRIGATED SOLAR PANEL AND SOLAR COLLECTOR

CLEANING SYSTEM

FIELD OF THE INVENTION

The invention relates to the field of panel cleaning systems.

BACKGROUND

Residential and commercial solar energy generation and/or collection panels (hereinafter "panels") are installed for many reasons. The primary reason, of course, is to reduce the cost of electricity to a home or business. Many people are also trying help the environment by reducing dependence on fossil fuels.

Solar panels typically have a top transparent cover that provides protection against weather and foreign objects. The transparent cover enables sunlight to pass through to solar energy collectors or photovoltaic cells that are positioned within the solar panels, below the transparent top. However, accumulation of dirt, dust, ash, leaves or other particles on the transparent cover can reduce the amount of sunlight that passes through to the solar energy collectors or photovoltaic cells, which can reduce the efficiency of the panels.

Elminir et al. (2006) describe an experiment performed in order to investigate the influence of dust on the performance of photovoltaic systems. The experimental setup involved 100 glass samples, of the type usually used in solar panels, installed at different tilt and azimuth angles. The transmittance of the glass was evaluated at regular intervals over a period of about seven months and after every thunderstorm in the surrounding area. The results showed that the reduction in normal transmittance of glass depends strongly on the dust deposition density in conjunction with tilt angle, as well as on the orientation of the surface with respect to the dominant wind direction. With this consideration, one sees that as the dust deposition density goes from 15.84 to 4.48 g/m2, the corresponding transmittance diminishes by 52.54-12.38%, respectively. See H. K. Elminir et al., " Effect of dust on the transparent cover of solar collectors' ', Energy conversion and Management 47 (2006) 3192-3203.

Manual cleaning methods, such as rinsing the transparent cover with water or scrubbing the glass top with a cloth, are typically used to remove these particles from the glass top to limit reductions in efficiency of the solar panel. However, manual cleaning may be inconvenient or difficult to perform because solar panels may be positioned on roof tops or other locations that are difficult to access. Manual cleaning also relies on a person being present to perform the manual cleaning, which may limit the frequency with which the solar panels are cleaned.

Automatic cleaning systems for solar panels have been suggested. Such systems usually utilize brushes and/or wipers in conjunction with spraying of water, with or without a cleaning agent. Thus, such systems require connection to water supply.

European Patent Application Publication No. EP2048455 to Diaz et al. discloses a system which comprises longitudinal rails; cleaning brushes; a drive unit mounted with possibility of linear displacement along the longitudinal rails and provided with at least one motor element for the rotational actuation of the cleaning brushes and the movement of said cleaning brushes, together with the drive unit, along the longitudinal rails; an electric control panel; and a rain sensor for the automatic start-up of the drive unit.

According to an April 16, 2012 news story, Stefi Development Ltd. of Kibbutz Na'an, Israel, has developed technology for cleaning solar panels with almost no water, utilizing night dew. See Anson, C. (April 16, 2012). Stefi Development Introduces Automatic System for Cleaning Solar Panels (in Hebrew). Tashtiot Portal. Retrieved from http://www.tashtiot.co.il/2012/04/16/%D7%A1%D7%98%D7%A4%D7%99/.

The foregoing examples of the related art and limitations related therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the figures.

SUMMARY

The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools and methods which are meant to be exemplary and illustrative, not limiting in scope.

There is provided, in accordance with an embodiment, a naturally-irrigated cleaning add-on for a solar panel or a solar collector, comprising: at least one wiper track mountable on at least one side, respectively, of a frame of said solar panel or said solar collector; a wiping unit configured to travel along said at least one wiper track, to clean a transparent front cover of said solar panel or said solar collector; and an automatic actuator configured to actuate said wiping unit upon detection of dew and/or precipitation. There is further provided, in accordance with an embodiment, a solar panel or a solar collector with a naturally-irrigated cleaning system, comprising: a housing for said solar panel or said solar collector, said housing comprising a frame and a transparent front cover, wherein said frame comprises at least one wiper track; a wiping unit disposed on said transparent front cover and configured to travel along said at least one wiper track; and an automatic actuator configured to actuate said wiping unit upon detection of dew and/or precipitation.

In some embodiments, said at least one wiper track comprises two wiper tracks each mountable on an opposing side of said frame.

In some embodiments, said wiping unit comprises a cog wheel.

In some embodiments, said at least one wiper track comprises grooves matching said cog wheel.

In some embodiments, said at least one wiper track comprises cogs matching said cog wheel.

In some embodiments, said wiping unit further comprises a motor coupled to said cog wheel, for moving said wiping unit along said at least one wiper track.

In some embodiments, said at least one wiper track comprises a motor interfacing with said cog wheel via a chain, for moving said wiping unit along said at least one wiper track.

In some embodiments, the naturally-irrigated cleaning add-on further comprises at least one of a dew sensor and a precipitation sensor connected to said automatic actuator.

In some embodiments, the solar panel or solar collector further comprises at least one of a dew sensor and a precipitation sensor connected to said automatic actuator.

In some embodiments, the naturally-irrigated cleaning add-on further comprises at least one photovoltaic panel for providing power to said automatic actuator.

In some embodiments, the solar panel or solar collector further comprises at least one photovoltaic panel for providing power to said automatic actuator.

In some embodiments, the naturally-irrigated cleaning add-on further comprises a cover for said wiping unit.

In some embodiments, the solar panel or solar collector further comprises a cover for said wiping unit. In some embodiments, said automatic actuator is configured to reciprocate said wiping unit over the transparent front cover during times of intense solar radiation, such that said cover shades different areas of said transparent front cover.

In some embodiments, said wiping unit further comprises a brush for scrubbing off stubborn dirt from the transparent front cover.

In some embodiments, said automatic actuator is further configured to actuate said wiping unit according to a schedule.

In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the figures and by study of the following detailed description.

BRIEF DESCRIPTION OF THE FIGURES

Exemplary embodiments are illustrated in referenced figures. Dimensions of components and features shown in the figures are generally chosen for convenience and clarity of presentation and are not necessarily shown to scale. The figures are listed below.

Fig. 1 shows a cleaning system for a single solar panel or multiple solar panels, in accordance with an embodiment;

Fig. 2 shows an enlarged portion of Fig. 1; and

Fig. 3 shows another enlarged portion of Fig. 1.

DETAILED DESCRIPTION

A naturally-irrigated cleaning system for a solar panel or a solar collector (collectively referred to, for simplicity of discussion, as "solar panel") is disclosed herein. Advantageously, the cleaning system may utilize natural, limescale-free dew, and/or in some embodiments precipitation, to clean the solar panel. This may obviate the need for external water supply, and thus provide for a simple and easy-to-use system. Furthermore, the cleaning system is compactly designed, making it suitable for installation on a single solar panel or for integral formation with a single solar panel. In some embodiments, however, the system is constructed to clean an array of multiple solar panels.

The cleaning system may include a wiper configured to travel on and wipe a front transparent cover of the solar panel by utilizing one or more, for example two wiper tracks which are disposed along opposing sides of a rectangular frame of the solar panel. In an embodiment, the wiper includes a cog wheel on one or more of its sides, and the wiper tracks have matching grooves or cogs. A motor coupled to the cog wheel is used to move the wiper along the tracks. In a different embodiment, a motor is included separately from the wiper, such as in or on one or more of the tracks, and a chain inside one or more of the tracks interfaces with a cog wheel on the wiper.

A computerized control unit (also referred to as an "automatic actuator") is used to control operation of the cleaning system. The control unit may be configured to facilitate at least one of two modes of operation: a detection-based mode, and a combined detection/time-based mode. In the detection-based mode, the control unit may be connected to a dew sensor, a precipitation (rain, hail and/or snow) sensor and/or the like, so as to activate the wiper at times when the front transparent cover of the solar panel is sufficiently wet to allow efficient wiping.

In the combined detection/time-based mode, the control unit may be preset to activate the wiper according to a schedule, such as every night at a set hour, subject to the condition that the dew and/or precipitation sensors indicate that the front transparent cover of the solar panel is sufficiently wet; otherwise, operation of the wiper on a dry cover may damage the cover. In other words, wiping may be activated not every time the transparent cover is wet, but rather only if the cover is wet and has not been wiped over a pre-programmed amount of time. The hour of operation may change according to one or more parameters pre-programmed in the control unit. Additionally or alternatively, the control unit may be re-programmed remotely, such as via a wired or wireless Internet connection.

Reference is now made to Fig. 1, which shows a cleaning system for a single or multiple solar panels, in accordance with an embodiment. Reference is also made to Figs. 2 and 3 which show enlargements of areas 200 and 300, respectively, of Fig. 1. Fig. 1 shows two solar panels 100 and 102 mounted in a row, but is intended to cover scenarios where a single cleaning system is used to clean multiple (two or more) panels mounted in a row, or only a single panel - whether it is mounted individually or in a row with more panels.

Solar panels 100 and 102 may include, for example, two opposing tracks 104 and 106, being either part of a chassis on which the panels are mounted or an add-on to the chassis or the panels. Optionally, tracks 104 and 106 may laterally protrude from at least one side of the row, as designated by reference numeral 108. This protrusion may allow the mounting of additional parts of the cleaning system, as discussed below. One or both tracks 104 and 106 may include a cover for preventing dirt from entering the tracks and accumulating within them.

The cleaning system further includes an elongated wiper, such as wiper 110, which may be made of a suitable waterproof, resilient material such as rubber, silicone and/or the like. Wiper 110 optionally extends to the entirety of the height of panels 100 and 102, from one track 104 to another 106. Wiper 110 may be detachably mounted on a wiper arm 112, to enable replacement of the wiper with a new one when it gets worn. One or more springs 124 may interface between wiper 110 and wiper arm 112, to resiliency press the wiper against the front cover of panels 100 and/or 102. Springs 124 may further allow wiper 110 to assume a different angle relative to transparent cover of panels 100 and/or 102 upon movement in different directions. For example, springs 124 may allow wiper 110 to assume an 80 degrees angle when moving to one side, and a 100 degrees angle when moving to the other side.

Additionally or alternatively, springs 124 may help facilitate movement of wiper 110 between one panel to the other. Since panels 100 and 102 may each include a frame which encompasses their transparent covers and is slightly heightened relative to the covers, springs 124 may allow wiper 110 to sufficiently retract when traveling over the heightened frame, upon moving from one panel to another.

Wiper 110 and wiper arm 112 may be jointly referred to as a wiper unit.

Optionally, the wiper unit may include a plurality of wipers, each similar to wiper 110, which are disposed parallel to each other and at a certain distance (e.g. a few millimeters or centimeters) from each other.

Optionally, an elongated brush, such as brush 114, may be included in the wiper unit, such as via mounting on wiper arm 112, to scrub off stubborn dirt which may not be easily wiped by wiper 110.

The cleaning system further includes one or more motors, such as motors 116a and 116b, to enable the wiper unit to travel along tracks 104 and 106. In the embodiment shown in the figures, the wiper unit includes a motor on each side, the two motors being attached to wiper arm 112 and constitute part of the wiping unit. Motor 116a drives cog wheel 118 and motor 116b drives cog wheel 120, wherein each of the cog wheels engages matching grooves (not shown) in tracks 104 and 106, respectively, and causes the wiping unit to travel along the tracks and clean panels 100 and/or 102. In another embodiment (not shown), a single motor may drive both of cog wheels 118 and 120 through a transmission such as a connecting rod or the like. An optional cover 122 for the wiping unit may be provided, to protect the wiping system from harsh environmental conditions. Cover 122 optionally covers an area larger than the wiping unit, so as to provide some shading to panels 100 and 102 during times of intense solar radiation which may harm the panels. During such days, the wiping unit may remain docked over one or more of panels 100 and 102 when not wiping, instead of being docked in the area of protrusion 108. Optionally, the wiping unit may slowly reciprocate over panels 100 and 102 during such days, so as to provide shading more equivalently to different areas. This reciprocating may be controlled by the computerized control unit described below.

Additionally or alternatively, the area of protrusion 108 may include a stationary cover (not shown) for the wiping unit. The wiping unit may remain covered by such stationary cover when not in use.

The cleaning system further includes a computerized control unit (also referred to as an "automatic actuator") 126, configured to actuate the wiping unit and cause it to clean the front cover of panels 100 and/or 102, upon detection of dew and/or at times when dew is expected to condensate on the front cover. Automatic actuator 126 is optionally positioned at protrusion 108, delimited between panel 100 and a delimiter 108a. Automatic actuator 126 may include an integrated circuit having at least a hardware processor. One or more of a dew sensor, a precipitation sensor, a hygrometer and/or the like may be connected to or included with automatic actuator 126, for activating the wiper at times when indicated that the front transparent cover of the solar panel is sufficiently wet to allow efficient wiping. Additionally or alternatively, timer functionality may be included in automatic actuator 126, enabling the presetting of a future time of activation of the wiping unit. Optionally, automatic actuator 126 may be re -programmed remotely, such as via a wired or wireless Internet connection.

Automatic actuator 126 may include a man-machine interface (MMI), comprised of buttons, a touch screen, a passive screen and/or of the like, for enabling a user to program activation times, view activation data and statistics, and/or the like. Additionally or alternatively, control of automatic actuator 126 may be possible through the aforementioned wired or wireless Internet connection or a different remote connection.

The cleaning system may be powered via one or more of the following options: through power generated by panels 100 and/or 102 (if the panels are photovoltaic); through power received from a mains connection 128; or through power generated by a dedicated photovoltaic panel 130. In either case, a rechargeable battery (not shown) may be provided, for powering the cleaning system at times when no power or no sufficient power is available otherwise.

In the description and claims of the application, each of the words "comprise" "include" and "have", and forms thereof, are not necessarily limited to members in a list with which the words may be associated. In addition, where there are inconsistencies between this application and any document incorporated by reference, it is hereby intended that the present application controls.

Claims

CLAIMS What is claimed is:

1. A naturally-irrigated cleaning add-on for a solar panel or a solar collector, comprising:

at least one wiper track mountable on at least one side, respectively, of a frame of said solar panel or said solar collector;

a wiping unit configured to travel along said at least one wiper track, to clean a transparent front cover of said solar panel or said solar collector;

an automatic actuator configured to actuate said wiping unit upon detection of dew and/or precipitation.

2. The naturally-irrigated cleaning add-on according to claim 1, wherein said at least one wiper track comprises two wiper tracks each mountable on an opposing side of said frame.

3. The naturally-irrigated cleaning add-on according to claim 1, wherein said wiping unit comprises a cog wheel.

4. The naturally-irrigated cleaning add-on according to claim 3, wherein said at least one wiper track comprises grooves matching said cog wheel.

5. The naturally-irrigated cleaning add-on according to claim 3, wherein said at least one wiper track comprises cogs matching said cog wheel.

6. The naturally-irrigated cleaning add-on according to any one of claims 3-5, wherein said wiping unit further comprises a motor coupled to said cog wheel, for moving said wiping unit along said at least one wiper track.

7. The naturally-irrigated cleaning add-on according to any one of claims 3-5, wherein said at least one wiper track comprises a motor interfacing with said cog wheel via a chain, for moving said wiping unit along said at least one wiper track.

8. The naturally-irrigated cleaning add-on according to claim 1, further comprising at least one of a dew sensor and a precipitation sensor connected to said automatic actuator.

9. The naturally-irrigated cleaning add-on according to claim 1, further comprising at least one photovoltaic panel for providing power to said automatic actuator.

10. The naturally-irrigated cleaning add-on according to claim 1, further comprising a cover for said wiping unit.

11. The naturally-irrigated cleaning add-on according to claim 10, wherein said automatic actuator is configured to reciprocate said wiping unit over the transparent front cover during times of intense solar radiation, such that said cover shades different areas of said transparent front cover.

12. The naturally-irrigated cleaning add-on according to claim 1, wherein said wiping unit further comprises a brush for scrubbing off stubborn dirt from the transparent front cover.

13. The naturally-irrigated cleaning add-on according to claim 1, wherein said automatic actuator is further configured to actuate said wiping unit according to a schedule.

14. A solar panel or a solar collector with a naturally-irrigated cleaning system, comprising:

a housing for said solar panel or said solar collector, said housing comprising a frame and a transparent front cover, wherein said frame comprises at least one wiper track;

a wiping unit disposed on said transparent front cover and configured to travel along said at least one wiper track; and

15. The solar panel or a solar collector according to claim 14, wherein said at least one wiper track comprises two wiper tracks each disposed at an opposing side of said frame.

16. The solar panel or a solar collector according to claim 14, wherein said wiping unit comprises a cog wheel.

17. The solar panel or a solar collector according to claim 16, wherein said at least one wiper track comprises grooves matching said cog wheel.

18. The solar panel or a solar collector according to claim 16, wherein said at least one wiper track comprises cogs matching said cog wheel.

19. The solar panel or a solar collector according to any one of claims 16-18, wherein said wiping unit further comprises a motor coupled to said cog wheel, for moving said wiping unit along said at least one wiper track.

20. The solar panel or a solar collector according to any one of claims 16-18, wherein said at least one wiper track comprises a motor interfacing with said cog wheel via a chain, for moving said wiping unit along said at least one wiper track.

21. The solar panel or a solar collector according to claim 14, further comprising at least one of a dew sensor and a precipitation sensor connected to said automatic actuator.

22. The solar panel or a solar collector according to claim 14, further comprising at least one photovoltaic panel for providing power to said automatic actuator.

23. The solar panel or a solar collector according to claim 14, further comprising a cover for said wiping unit.

24. The solar panel or a solar collector according to claim 23, wherein said automatic actuator is configured to reciprocate said wiping unit over the transparent front cover during times of intense solar radiation, such that said cover shades different areas of said transparent front cover.

25. The solar panel or a solar collector according to claim 14, wherein said wiping unit further comprises a brush for scrubbing off stubborn dirt from the transparent front cover.

26. The solar panel or a solar collector according to claim 14, wherein said automatic actuator is further configured to actuate said wiping unit according to a schedule.