NL2034421B1 - A collecting system for solar energy such as heat or light - Google Patents

Abstract

The invention relates to a collecting system for solar energy such as heat or light, comprising: — a collector comprising a collecting area and an optical element such as for example a Fresnel lens or a concave mirror, which optical element focuses solar energy from the collecting area onto a smaller accumulating area; — a tracking subsystem on which the collector is mounted, which tracking subsystem comprises a pitch arm driven by a pitch motor for varying a pitch angle of the collector and an azimuth arm driven by an azimuth motor for varying an azimuth angle of the collector, which tracking subsystem further comprises a controller configured for controlling the pitch motor and azimuth motor for varying the pitch angle and the azimuth angle of the collector for optimizing the amount of solar energy reaching the collecting area; — an accumulator positioned in the accumulating area, the accumulator comprising means for relaying the 20 accumulated solar energy to a different location, the accumulator being for example a light tube or a heat storage.

Description

A collecting system for solar energy such as heat or light

The present invention relates to a collecting system for solar energy such as heat or light. In order to effectively use the abundance solar energy available on earth, many solutions exist to put the energy to use.

In many cases, the solar energy is converted into other energy forms, such as for example into electricity with photovoltaic solar panels. In other known systems, the solar energy is captured for water heating, by directly heating water flowing through a hydraulic system.

A drawback of the known systems, is that duite significant losses occur during conversion and that no scalable storage solutions are available for the converted energy forms. While some form of storage is used with water heating in the form of buffer tanks, the amount of heat that can be stored is rather limited due to high pressures which would occur if more energy would be stored in a certain volume of liquid.

It is now an object of the invention to reduce or even obviate the above stated drawbacks.

This object is achieved according to the invention by supplying a collecting system for solar energy such as heat or light, comprising: — a collector comprising a collecting area and an optical element such as for example a Fresnel lens or a concave mirror, which optical element focuses solar energy from the collecting area onto a smaller accumulating area; — a tracking subsystem on which the collector is mounted, which tracking subsystem comprises a pitch arm driven by a pitch motor for varying a pitch angle of the collector and an azimuth arm driven by an azimuth motor for varying an azimuth angle of the collector, which tracking subsystem further comprises a controller configured for controlling the pitch motor and azimuth motor for varying the pitch angle and the azimuth angle of the collector for optimizing the amount of solar energy reaching the collecting area; - an accumulator positioned in the accumulating area, the accumulator comprising means for relaying the accumulated solar energy to a different location, the accumulator being for example a light tube or a heat storage.

The system concentrates the solar energy falling on or through the collecting area to the accumulating area, increasing the intensity of the solar energy per unit of surface. The focusing can be performed by an optical element such as for example a Fresnel lens or a concave mirror. Both a

Fresnel lens and a concave mirror allow for a large surface of the collecting area, without increasing the weight of the system to absurd amounts. The collecting area can be formed by several optical elements. By mounting the collector on the tracking subsystem, the output of the collecting system can be increased by following the sun throughout the day. To that end, the tracking subsystem is supplied with two arms for controlling both the pitch angle and azimuth angle. The pitch arm is driven by a pitch motor and the azimuth arm is driven by an azimuth motor. A controller coordinates both angles for optimizing the amount of solar energy reaching the collecting area. Ultimately, an accumulator is positioned in the accumulating area, whereby the accumulator relays the concentrated solar energy to a different location. The solar energy is thereby relayed without conversion, so in case of relaying the light component of the solar energy, it is relayed to a different location through for example a light tube. In the case of heat, the accumulated heat is relayed to a different location by means of heat storage.

In another embodiment of a collecting system according to the invention, the accumulator is a heat storage, said heat storage comprising a core such as a metal core for storing solar heat, which core is surrounded by and suspended in an encasing which is thermally insulated from the core, and which encasing has a solar energy transmitting section positioned in the accumulating area for heating the core with the scolar energy falling thereon through the transparent section.

By supplying a heat storage with a core for storing the heat, the accumulated solar energy can be easily relayed to different locations by moving the core. By using for example a metal core such as a cast iron core, a very high energy density can be obtained, without risking high pressure causing problems. The core is insulated by means of an encasing in which it is suspended. The insulation can for example be formed by a vacuum within the encasing but other suitable means can be employed as well. A section that allows solar energy to be transmitted into the encasing and onto the core, such as for example a translucent section, is provided for efficient heating of the core. Preferably the translucent section allows solar radiation to enter the encasing, but is 2b reflective for said radiation in the reverse direction.

Preferably, the encasing further comprises a cover for covering the transmitting section.

By being able to cover the transmitting section, which may allow for a higher leakage of heat radiation, the retaining of heat may be greatly increased by improved insulation of the core of the heat storage.

In a preferred embodiment of the collecting system according to the invention, the heat storage is movable and the collecting system further comprises: - a transport subsystem comprising a mover, which mover 1s configured for moving the heating core between the accumulating area and a usage area.

By allowing the heat storage to be movable between the accumulating area and a usage area, the accumulated heat can be used in a place further located away from the collecting system. The stored heat can for example be used to heat a housing complex in the usage area, whereby the transport subsystem transports the heat storage between said usage area and the accumulating area. Several heat storages may also be used, to increase the total capacity of the system.

Also according to the invention, is an embodiment of a collecting system in which the mover is autonomously movable and the transport subsystem comprises a transport controller for coordinating the movement of the mover.

By controlling autonomously movable movers, the supply of heat to the usage area can be fully automatic. Heat stores which have depleted can be brought back to the accumulating area for re-heating and vice versa.

Also an embodiment of a collecting system according to the invention, is a collecting system wherein the controller of the tracking subsystem coordinates positioning the accumulating area with the transport controller.

By coordinating the positioning of the accumulating area by pivoting the collecting area around one or both axes with the movement of the mover, further benefits can be obtained. It can be prevented by coordinating the movements that the mover has to enter or closely approach the accumulating area, in which the high heat and/or light intensity may be problematic.

In yet another embodiment of a collecting system according to the invention, the pitch arm extends from a base and is pivotable around a first axis and wherein a frame is attached to the free end of the pitch arm, wherein furthermore the azimuth arm is connected to the frame and is pivotable 5 around a second axis, which first and second axis are not parallel, preferably are perpendicular to each other.

By providing a frame which is pivotable by means of the pitch arm around the first axis and allowing the azimuth arm to be pivotably connected to the frame for allowing the collecting area to pivot around the second axis, the required degrees of freedom for tracking the sun can be obtained. It will be clear that based on the respective orientation, the functions of the arms may be interchangeable. The greatest area can be covered when the first and second axis are perpendicular to each other.

These and other features of the invention are further elucidated with reference to the accompanying drawings.

Figure 1 shows a schematic view of an embodiment of a collecting system according to the invention.

Figure 2 shows a cross-section of a heat storage according to the invention.

In figure 1, an embodiment of a collecting system 1 according to the invention is shown. A a pair of pitch arms 2 extend from a base 3. The pitch arms 2 are pivotable around a first axis 4 which runs through pivot anchors 5. The frame 6 is attached to the free end 7 of the pitch arms 2. The azimuth arm 8 is pivotably connected to the frame 7 and is pivotable around a second axis 9. The first axis 4 and the second axis 9 are clearly not parallel. The collecting area 10 is formed by three Fresnel lenses 10. The azimuth motor 11 allows the azimuth arms 8 to pivot in the direction of the arrows 12, due to the attached linkage. The Fresnel lenses 10 focus the incoming light onto the accumulating area 14. The frame 6 can be pivoted around the pivot anchors 5 as indicated by the arrow 15 by the pivot motor 16. In the accumulating area 14 a heat storage 17 is located in which a cast iron core 18 is exposed to the focused solar energy. An autonomously movable mover 19 is transporting a depleted heat storage 20 towards the accumulating area 14.

In figure 2 a cross-section is shown of a heat storage 21 according to the invention. A cast iron core 22 is suspended on an insulated ring 23 within an enclosure 24. As a means of insulating, the inside 25 of the enclosure 24 is subjected to a vacuum. The top of the enclosure 24 is sealed by means of translucent pane 26. On the inside, a one-way mirror 27 is applied for retaining heat. Solar energy radiation 28 can enter the enclosure, but radiation 29 from the heated core 22 is largely reflected back into the casing.

As an optional or alternative measure for the one-way mirror 27, a lid {not shown) may be provided for the heat storage.

:

Clauses 1. A collecting system for solar energy such as heat or light, comprising: — a collector comprising a collecting area and an optical element such as for example a Fresnel lens or a concave mirror, which optical element focuses solar energy from the collecting area onto a smaller accumulating area; - a tracking subsystem on which the collector is mounted, which tracking subsystem comprises a pitch arm driven by a pitch motor for varying a pitch angle of the collector and an azimuth arm driven by an azimuth moter for varying an azimuth angle of the collector, which tracking subsystem further comprises a controller configured for controlling the pitch motor and azimuth motor for varying the pitch angle and the azimuth angle of the collector for optimizing the amount of solar energy reaching the collecting area; - an accumulator positioned in the accumulating area, the accumulator comprising means for relaying the accumulated solar energy to a different location, the accumulator being for example a light tube or a heat storage. 2. Collecting system according to clause 1, wherein the accumulator is a heat storage, said heat storage comprising a core such as a metal core for storing solar heat, which core is surrounded by and suspended in an encasing which is thermally insulated from the core, and which encasing has a solar energy transmitting section positioned in the accumulating area for heating the core with the solar energy falling thereon through the transparent section. 3. Collecting system according to clause 2, wherein the encasing further comprises a cover for covering the transmitting section. 4. Collecting system according to clause 2 or 3,

wherein the heat storage is movable and which collecting system further comprises:

- a transport subsystem comprising a mover, which mover 1s configured for moving the heating core between the accumulating area and a usage area.

5. Collecting system according to clause 4, wherein the mover is autonomously movable and the transport subsystem comprises a transport controller for coordinating the movement of the mover.

6. Collecting system according to clause 4 or 5, wherein the controller of the tracking subsystem coordinates positioning the accumulating area with the transport controller.

7. Collecting system according to any one of the preceding clauses, wherein the pitch arm extends from a base and is pivotable around a first axis and wherein a frame is attached to the free end of the pitch arm, wherein furthermore the azimuth arm is connected to the frame and is pivotable around a second axis, which first and second axis are not parallel, preferably are perpendicular to each other.

Claims (7)

Conclusions 1. A collector system for solar energy such as heat or light, comprising: - a collector having a collection area and an optical element such as, for example, a Fresnel lens or a concave mirror, which optical element focuses the solar energy from the collection area onto a smaller accumulation area; - a tracking subsystem on which the collector is mounted, which tracking subsystem comprises a pitch arm driven by a pitch motor for varying a pitch angle of the collector and an azimuth arm driven by an azimuth motor for varying an azimuth angle of the collector, which tracking subsystem further comprises a controller configured to control the pitch motor and the azimuth motor for varying the pitch angle and the azimuth angle of the collector to optimize the amount of solar energy reaching the collection area; - an accumulator in the accumulation area, which accumulator comprises means for transmitting the accumulated solar energy to another location, which accumulator is, for example, a light tube or a heat storage. 2. A collector system according to claim 1, wherein the accumulator is a heat storage device, said heat storage device comprising a core such as a metal core for storing solar heat, said core being surrounded by and secured in a housing thermally insulated from said core, and said housing comprising a solar energy transmissive section positioned in said accumulation area for heating said core with solar energy incident thereon through said transmissive section. 3. A collector system as claimed in claim 2, wherein the housing further comprises a lid for covering the permeable section. 4. Collector system according to claim 2 or 3, wherein the heat storage is movable and wherein the collector system further comprises: - a transport subsystem comprising a mover, which mover is configured to move the heat storage between the accumulation area and a usage area. 5. A collector system as claimed in claim 4, wherein the mover is autonomously movable and the transport subsystem comprises a transport controller for coordinating the movements of the mover. 6. A collector system according to claim 4 or 5, wherein the controller of the tracking subsystem coordinates the positioning of the accumulation area with the transport controller of the transport subsystem. 7. Collector system according to any of the preceding claims, wherein the pitch arm extends from a support surface and is pivotable about a first axis and wherein a frame is attached to the free end of the pitch arm, wherein the azimuth arm is also attached to the frame and is pivotable about a second axis, which first and second axes are not parallel, preferably perpendicular to each other.