Solar Energy Collecting Device

Abstract

A solar energy collecting device includes a spherical concentrator, a track, a sliding element, and at least one solar panel. The track is curved and has a center overlapping with that of the spherical concentrator. The sliding element is disposed on the track, and is controlled to move along the track according to the motion of the Sun during the course of a day. The solar panel is mounted on the sliding element to move along with the sliding element. The solar panel faces the spherical concentrator. Thus, the sunlight can be focused on the solar panel by the spherical concentrator throughout the day.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a solar energy collecting device that includes a solar panel moving according to the motion of the Sun.

2. The Prior Arts

Conventional solar thermal collectors or photovoltaic modules use a solar panel to collect the energy from the Sun and use the solar energy to generate electricity. Because the Earth spins on its axis, the Sun rises in the east and sets in the west. Furthermore, the Earth's axis is tilted to its orbital plane by an angle of 23.5 degrees and orbiting around the Sun. Therefore, the angles of incidence between the incoming sunlight and the normal of the solar panel vary with time and seasons. In order to minimize the angle of incidence and maximize the energy conversion efficiency, a tracker is provided to detect the angles of incoming sunlight and an actuator device is provided to rotate the solar panel making the solar panel perpendicular to the ray of light. In order to collect as much energy as possible, the size of the solar panel is usually very large. However, due to the bulky solar panel, it needs an actuator device that can drive a heavy load, which increases the cost of the whole system.

In order to reduce the size of the solar panel, some solar energy collecting devices are provided with concentrators (reflectors or lenses). Referring to FIG. 1, a solar energy collecting device has a concave reflective mirror A to reflect and focus the sunlight onto a solar panel B. Because the light from a large-sized reflective mirror A is concentrated onto the small-sized solar panel B, the manufacture cost of the solar panel is reduced. However, the reflective mirror A is large and needs to be rotated for facing the Sun directly. As a result, the solar energy collecting device still needs an actuator device that can drive the heavy load of the mirror. Therefore, the solar energy collecting device is still expensive and consumes a lot of power.

SUMMARY OF THE INVENTION

A primary objective of the present invention is to provide a solar energy collecting device, which solves the aforementioned problems of conventional designs that the cost of reflectors, lenses and actuator devices are high.

Another objective of the present invention is to provide a solar energy collecting device having a small-size solar panel which can be self adjusted according to the Earth's spinning about its own axis, thereby keeping the solar panel to be perpendicular to the ray of the Sun. Thus, the solar energy collecting device can receive optimal light irradiation as the angles of the incoming sunlight changes and does not need an expensive actuator device for driving heavy lenses or mirrors.

In order to accomplish the objectives mentioned above, a solar energy collecting device according to the present invention comprises a spherical concentrator, a track, a sliding element and at least one solar panel. The track is curved and concentric with the spherical concentrator. The sliding element is disposed on the track, and is controlled to move along the track according to the motion of the Sun during the course of a day. The solar panel is disposed on the sliding element and faces the spherical concentrator, such that the light is focused on the solar panel by the spherical concentrator.

The track can be mounted on another track or device to adjust the orientation of the track according to the angles of the incoming sunlight due to the season variation. Thus, it ensures that the sunlight is constantly focused on the track after traveling through the spherical concentrator.

According to an embodiment, the spherical concentrator is a solid sphere made of a material that can focus sunlight, such as glass and polyurethane.

According to another embodiment, the spherical concentrator is a hollow sphere made of glass or polyurethane and the interior of the spherical concentrator is filled with a liquid.

Because the concentrator is spherical, the focal point always falls on a line connecting the Sun and the center of the spherical concentrator, regardless of the motion of the Sun. The focal length depends on the diameter of the spherical concentrator, so the focal length is a constant. Therefore, as the Sun moves across the sky during the course of the day, the focal point would move along a circular path. The track is overlapped with the circular path. As a result, the solar energy collecting device according to the present invention only needs to control the small-sized solar panel to move along the circular path according to the motion of the Sun and the sunlight would be focused on the solar panel. Compared with conventional design, the present invention does not need to drive a heavy concentrator (lens or reflector), numerous concentrators or racks holding the concentrator and therefore the actuator device is greatly simplified.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be apparent to those skilled in the art by reading the following detailed description of preferred embodiments thereof, with reference to the attached drawings, in which:

FIG. 1 is a perspective view showing a conventional solar energy collecting device having a reflective mirror;

FIG. 2 is a schematic view showing a solar energy collecting device according to a first embodiment of the present invention;

FIG. 3 is a schematic view showing the solar energy collecting device of FIG. 2, wherein a solar panel mounted on a sliding element is moved along a track according to the motion of the Sun;

FIG. 4 is a schematic view showing a solar energy collecting device according to a second embodiment of the present invention; and

FIG. 5 is a schematic view showing the solar energy collecting device of FIG. 4, wherein a solar panel mounted on a sliding element is moved along a track according to the motion of the Sun.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 2, a solar energy collecting device according to a first embodiment of the present invention comprises a spherical concentrator 1, a track 2, a sliding element 3 and at least one solar panel 4. According to the first embodiment, the spherical concentrator 1 is a solid sphere made of a transparent material, such as glass, polyurethane (PU) and acrylic. The larger the diameter of the spherical concentrator 1 is, the larger area is provided to collect solar energy. Therefore, the diameter of the spherical concentrator 1 is selected according to the desired solar collecting area of the spherical concentrator 1. The track 2 is curved and has a center overlapping with that of the spherical concentrator 1. In other words, the track 2 is a part of a circle which has a predetermined radius and is concentric with the spherical concentrator 1. According to another embodiment, the track 2 may also include a plurality of straight segments forming the part of the circle. The solar panel 4 is fixed on the sliding element 3. The sliding element 3 is a carrier element provided with a driving device, such as a motor. The sliding element 3 may include wheels allowing the sliding element 3 to move along the track 2. The sliding element 3 is pre-programmed to move according to the motion of the Sun through the day. According to another embodiment, a conventional solar tracking device may be used to track the motion of the Sun in the sky and send signals to control movements of the sliding element 3, such that the light is focused by the spherical concentrator 1 on the surface of the solar panel 4 mounted on the sliding device 3.

When the Earth revolves around the Sun, the axis of the Earth is tilted 23.5 degrees from the perpendicular to the Earth-Sun plane. Because the axial tilt of the Earth, the angle of sunlight reaching any given point on the surface of the Earth varies over the course of the year (the northern hemisphere is exposed to direct sunlight in summer, and the southern hemisphere is exposed to direct sunlight in winter). In order to collect direct sunlight irradiation throughout the year, the track 2 can be mounted on another track or device (not shown in the drawings). Therefore, the orientation of the track 2 can be adjusted responding to the solar direction due to the season variation, which ensures the spherical concentrator 1 always concentrates the incoming light onto the solar panel 4.

The spherical concentrator 1 of the solar energy collecting device according to the first embodiment of the present invention is rather bulky and heavy, so the spherical concentrator 1 is held stationary. As sunlight emitted from the Sun 5 travels through the spherical concentrator 1, it is refracted and focused to converge on the solar panel 4. Referring to FIG. 3, when the Sun moves, the sliding element 3 is driven to move along the track 2 at a suitable speed to allow the converged light to always fall on the solar panel 4.

Referring to FIG. 4, a solar energy collecting device according to a second embodiment of the present invention comprises a hollow spherical concentrator 1A, a track 2, a sliding element 3 and at least one solar panel 4. The spherical concentrator 1A is a hollow sphere having an exterior shell and an interior space. The exterior shell of the spherical concentrator 1A is made of glass, polyurethane (PU), acrylic or similar transparent materials. The interior space of the hollow spherical concentrator 1A is filled with liquid 11, such as water. The liquid 11 may be another material having good transmittance of light. The diameter of the spherical concentrator 1 is selected according to the desired solar energy collecting area of the spherical concentrator 1. The track 2 is curved and has a center overlapping with that of the spherical concentrator 1. In other words, the track 2 is a part of a circle which has a predetermined radius and is concentric with the spherical concentrator 1A. According to another embodiment, the track 2 may also include a plurality of straight segments forming the part of the circle. The solar panel 4 is fixed on the sliding element 3. The same as the first embodiment, the sliding element 3 is a carrier element provided with a driving device. The sliding element 3 may include wheels allowing the sliding element 3 to move along the track 2. The sliding element 3 is programmed to move according to the motion of the Sun through the day. Alternatively, a conventional solar tracking device may be used to track the motion of the Sun in the sky and control movements of the sliding element 3, such that the incoming light is focused by the spherical concentrator 1A on the surface of the solar panel 4 disposed on the sliding device 3.

Referring to FIG. 5, as sunlight emitted from the Sun 5 travels through the spherical concentrator 1A and the liquid 11 according to the second embodiment of the present invention, it is refracted and focused to converge on the solar panel 4. When the Sun moves across the sky, the sliding element 3 is driven to move along the track 2 at a suitable speed to allow the converged light to always fall on the solar panel 4.

Although the present invention has been described with reference to the preferred embodiments thereof, it is apparent to those skilled in the art that a variety of modifications and changes may be made without departing from the scope of the present invention which is intended to be defined by the appended claims.

Claims

1. A solar energy collecting device, comprising:

a spherical concentrator;

a track being curved and concentric with the spherical concentrator;

a sliding element disposed on the track and driven to move along the track in accordance with a motion of the Sun; and

at least one solar panel mounted on the sliding element and facing the spherical concentrator;

wherein the solar panel is moved along with the sliding element such that the spherical concentrator focuses the light onto the solar panel.

2. The device as claimed in claim 1, wherein the spherical concentrator is a solid sphere made of glass.

3. The device as claimed in claim 1, wherein the spherical concentrator is a solid sphere made of polyurethane.

4. The device as claimed in claim 1, wherein the spherical concentrator is a hollow sphere having an exterior shell and an interior space filled with a liquid.

5. The device as claimed in claim 4, wherein the exterior shell of the hollow sphere is made of transparent polyurethane.

6. The device as claimed in claim 4, wherein the exterior shell of the hollow sphere is made of transparent glass.