BG4256U1 - Device for waste heat management of solar photovoltaic panels - Google Patents

Abstract

The device (1) constructed according to the utility model serves to increase the efficiency of the function of solar photovoltaic panels (2) to convert solar radiation into electricity. The device (1) actively removes waste heat from the solar photovoltaic panels (2), as a result of which increases the efficiency of converting solar radiation into electricity in the photovoltaic elements. At the same time, the device (1) enables conversion of waste heat in the thermoelectric cooling using the Peltier effect (8) into electricity, thus increasing the efficiency of the function of the solar photovoltaic panel (2) to conduct electricity. The heat pump (6) transports the unused waste heat from the solar photovoltaic panel (2) for further utilization.

Description

(54) DEVICE FOR WASTE HEAT MANAGEMENT OF SOLAR PHOTOVOLTAIC PANELS

Field of technique

A utility model refers to a device that allows more efficient use of the energy of the sun's rays falling on solar photovoltaic panels.

Prior art

Currently, solar photovoltaic panels are known, which convert the energy of the incident sunlight into electrical energy. The solar panel is made of a supporting base plate embedded in a frame. There is an electrode placed on the substrate on which photovoltaic cells made of silicon-based semiconductor elements are formed.

Semiconductor elements are located under a transparent covering layer, for example, made of glass with an anti-reflective coating.

Currently, known solar photovoltaic panel technologies have an energy conversion efficiency from incident sunlight of about 17% under optimal operating conditions. The remaining energy is converted into waste heat that heats the solar PV panel and this energy, without any use, is emitted to the environment of the solar PV panel. The most important operating conditions for a solar PV panel include the spatial orientation of the solar panel relative to the direction of solar radiation and the operating temperature.

In particular, the operating temperature of the solar PV panel is the most pressing problem to solve, because as the operating temperature increases, the already limited efficiency of the PV technology decreases. In addition, the life of photovoltaic cells is shortened because so-called hot spots occur, where waste heat causes the temperature to rise to about 100°C, leading to degradation (short circuit) of semiconductor cells.

The above description of the structure of the most used types of solar photovoltaic panels shows a major problem in the ability to dissipate or radiate waste heat, in particular when it is cooled by the surrounding air. This results in the unwanted paradox that, for our latitude and longitude, the efficiency of solar photovoltaic installations, in terms of ideal lighting conditions, in the warm summer months is less than in the other months when the air temperature is significantly lower. -low. The above-mentioned main problems related to the reduction of efficiency of solar photovoltaic panels due to the effect of waste heat have been solved, for example, by the technical solution of utility model CZ 19199, in which not only the panels are actively cooled with water to increase the efficiency of solar photovoltaic panels, but also eliminate the problems of non-ideal lighting conditions, by concentrating solar radiation through reflective surfaces.

Another known solution is invention WO 2018148796 A, in which a liquid circulation system cooling photovoltaic panels is described. In this solution, the solar photovoltaic panel waste heat management device includes at least one absorber located on the underside of the at least one solar photovoltaic panel for absorbing waste heat, wherein at least one thermal heat exchanger is connected in the first circuit of the heat pump. The invention also describes the possibility of using a Peltier cell to generate electricity. Another known technical solution is disclosed in utility model CN 203464537 U. In this technical solution, a device is presented that includes a solar photovoltaic system for actively removing waste heat from solar photovoltaic panels by means of a heat pump.

A major problem of the above solutions is that they create local cooling zones where the waste heat is actively pumped out, but at the same time they leave hot spots on the surface of the solar PV panel, in particular at the boundaries of the individual heat exchangers. The first negative impact is that the photovoltaic cells are wetted or even damaged, and the different temperatures on the surfaces of the photovoltaic panels create stresses in the material due to thermal expansion. These problems are a result of the fact that the heat exchangers are assembled from partial segments, so that the effect of thermal expansion, which is different for different materials, is minimized and that the photovoltaic panel is not damaged.

A major problem of the above solutions is due to the fact that the waste heat is not meaningfully recovered, even more so at a time when the value of water increases, its use is not appropriate.

The purpose of the utility model is to create a solar PV panel waste heat management device that effectively dissipates the waste heat from the solar panel to improve the efficiency of converting solar radiation into electricity while providing waste heat for more further processing. The second important goal of the utility model is that the total waste heat does not limit electricity production, but also contributes to electricity production.

Technical nature of the utility model

The defined task is solved by creating a device for managing the waste heat of solar photovoltaic panels, according to the following description.

The solar photovoltaic panel waste heat management device includes at least one absorber that is located on the back side of the at least one photovoltaic panel to absorb waste heat. The absorber is located below the solar photovoltaic panel in order not to limit the solar radiation falling on the photovoltaic elements. At least one heat exchanger is connected to the absorber. This heat exchanger is connected to the first circuit of the heat pump for active consumption of the waste heat from the absorber. The removal of waste heat has a positive effect on the efficiency of photovoltaic cells in the production of electricity. The heat exchanger is connected in the first loop of a heat pump that transports heat from the solar panel for further processing. This means that waste heat is not emitted into the environment without proper use. At the same time, at least one Peltier cell is connected to the absorber. This Peltier cell is flat and has a heating and cooling side, where at least one Peltier cell produces electrical energy due to the different temperatures between the heating and cooling sides.

The technical essence of the utility model is that the absorber includes a homogenizing plate mounted on the back of a photovoltaic panel. Applied to the back of the panel, the homogenizing plate receives waste heat from the photovoltaic cells, thus preventing the creation of hot spots. Waste heat is not concentrated in points on the surface of the solar panel, but is distributed over the entire surface of the homogenizing plate. This prevention of hot spots protects the photovoltaic cells from damage by limiting the heat so as to prevent short circuits caused by overheating or interruption of the conductive paths from overheating between the photovoltaic cells. Additionally, between the back of the solar photovoltaic panel and the homogenizing plate, and additionally, between the homogenizing plate and the heat exchanger, there is a layer of non-hardening thermally conductive paste. Since the photovoltaic panel, the homogenizing plate and the heat exchanger are made of different materials, different dimensional changes occur due to thermal changes. Therefore, it is necessary that the individual components of the absorber are not tightly fastened and stress caused by tension is avoided.

At the same time, the homogenizing plate leaves at least a part of the back side of the photovoltaic panel uncovered to keep the waste heat in place, and at least one heat collector is connected to the uncovered part of the back side of the photovoltaic panel. The uncovered part of the panel is heated in the same way as before for panels without the absorber. However, this waste heat that is not absorbed by the absorber is fed to the heat collector for further processing. At least one Peltier cell is used to recover waste heat from the heat collector. This at least one Peltier cell is located with the heating side to the homogenizing plate and is connected to the heat collector, and is connected with the cooling side to at least one thermally conductive junction. In this way, some of the waste heat is used to create a thermal difference across at least one Peltier cell, which at this point begins to generate electricity.

The utility model combines three main advantages. The first advantage is that by actively cooling the solar photovoltaic panel, the efficiency of the production of electricity from solar energy is increased. The second main advantage is that waste heat is dissipated for further processing. An ideal example of using this advantage is, for example, the installation of such a device to solar photovoltaic panels in the area of a sawmill, where the energy in the form of heat can be used in a wood dryer, possibly the waste heat can be used to heat swimming pools . The third important advantage is the conversion of part of the waste heat into electricity with the help of the created device. Converting waste heat into electricity can compensate for poor lighting conditions or reduced efficiency due to windy conditions, but in any case, the conversion increases the energy balance of solar PV panels.

In the advantageous embodiment of the solar photovoltaic panel waste heat management device according to the utility model, the uncovered part of the back side of the solar photovoltaic panel is located at its lower edge in terms of the installation orientation of the solar photovoltaic panel. This is especially important when installing solar panels in continuous solar arrays on building roofs. If a hot area is left at the bottom of the solar PV panel, the heat will rise due to the natural tendency, causing the so-called chimney effect of air flow in the space between the roof and the panels.

In another advantageous embodiment of the photovoltaic solar panel waste heat management device, according to the utility model, the homogenizing plate and the heat collector are made of the same material, have the same volume of material with a tolerance of +/- 20% of the volume. Approximately the same volume values of the two components of the device, including the same kind of material, lead to the same behavior of the thermodynamic response when the environmental conditions change, such as sudden temperature changes, etc.

In another advantageous embodiment of the photovoltaic solar panel waste heat management device, according to the utility model, at least one storage tank is connected to the first circuit of the heat pump. The storage tank serves as a buffer against sudden temperature changes. Alternatively, the storage tank can serve as a heat source for defrosting in the event of a heat pump reverse cycle.

In another advantageous embodiment of the device for managing the waste heat of solar photovoltaic panels, according to the utility model, a vacuum expansion vessel is connected to the first circuit of the heat pump, consisting of a vessel body for closing a liquid heat transfer medium and a bubble for the gaseous medium inside the hull. By changing the design, compared to other conventional vacuum expansion vessels, i.e. changing the location of the air and the liquid heat transfer medium in the vacuum expansion vessel, any shock caused by pressure changes that can propagate through the liquid heat transfer medium is eliminated thanks to the vacuum expansion vessel.

In another alternative embodiment of the device for managing waste heat of solar photovoltaic panels, which can operate without an external energy source, the device includes at least one absorber located on the underside of at least one solar photovoltaic panel for absorbing waste heat, wherein at least one heat exchanger is connected to the first circuit of the heat pump and, at the same time, at least one Peltier cell is connected to the absorber with the heating and cooling side for generating electricity. The absorber includes a homogenizing plate located on the back side of the solar photovoltaic panel. The heat exchanger is connected to the free side of the homogenizing plate and it covers at least part of the back side of the photovoltaic panel. Additionally, there is a layer of non-hardening, thermally conductive paste between the back of the solar PV panel, the homogenizing plate and the heat exchanger. At least one heat collector with at least one heat-conducting transition is arranged to the uncovered part of the rear side of the solar photovoltaic panel, and at least one Peltier cell is attached with the heating side to the homogenizing plate and the cooling side to the heat-conducting transition. This device also includes at least one storage of electrical energy connected to the solar photovoltaic panels, such as the heat pump, simultaneously connected to the solar photovoltaic panel and to the storage of electrical energy. By incorporating an energy storage device into the device, it gains energy independence and the ability to operate in the so-called island mode, where the device is completely independent of an external artificial energy source. Using solar panels, the device is able to achieve maximum use of a renewable energy source represented by solar radiation, which makes its operation completely ecological, cheap and safe for the environment.

In a favorable embodiment of the alternative embodiment of the solar photovoltaic panel waste heat management device according to the utility model, the exposed portion of the back side of the solar photovoltaic panel is located at its lower edge from the point of view of the installation orientation of the solar photovoltaic panel. This is especially important when installing solar panels in continuous solar arrays on building roofs. If a hot area is left at the bottom of the solar PV panel, the heat will rise due to the natural tendency, causing the so-called chimney effect of air flow in the space between the roof and the panels.

In another advantageous embodiment of the alternative embodiment of the photovoltaic solar panel waste heat management device, or according to its previous advantageous embodiment, according to the utility model, the homogenizing plate and the heat collector are made of the same material, have the same volume of material with tolerance +/- 20% of volume. Approximately the same volume values of the two components of the device, including the same kind of material, lead to the same behavior of the thermodynamic response when the environmental conditions change, such as sudden temperature changes, etc.

In another advantageous embodiment of the alternative embodiment of the device for managing the waste heat of the photovoltaic solar panels, or according to any preceding advantageous embodiment thereof, according to the utility model, at least one storage tank is connected to the first circuit of the heat pump. The storage tank serves as a buffer for sudden temperature changes. Alternatively, the storage tank can serve as a heat source for defrosting in the event of reverse duty cycle of the heat pump.

In another favorable embodiment of the alternative embodiment of the device for managing the waste heat of the photovoltaic solar panels, or according to any preceding favorable embodiment thereof, according to the utility model, a vacuum expansion vessel is connected to the first loop of the heat pump, consisting of a vessel body for closure of a liquid heat transfer medium and a bubble for the gaseous medium inside the casing. By changing the design, compared to other conventional vacuum expansion vessels, i.e. changing the location of the air and the liquid heat transfer medium in the vacuum expansion vessel, any shock caused by pressure changes that can propagate through the liquid heat transfer medium is eliminated thanks to the vacuum expansion vessel.

The advantages of the utility model are higher efficiency in converting solar radiation into electricity, greater electricity production by processing part of the waste heat into electricity, extending the life of solar PV panels, easy installation on existing solar PV panels, and already existing load-bearing structures, energy self-sufficiency and last but not least, the production of heat for direct use.

Explanation of the attached figures

The utility model will be explained more precisely by the following drawing, where:

Figure 1 shows a schematic diagram of the device according to the utility model;

Figure 2 shows a simplified bottom view of a solar photovoltaic panel with absorption components and equipment for converting waste heat into electricity;

Figure 3 shows airflow under the solar panels on a pitched roof.

Examples of implementations of the utility model

It is understood that the specific exemplary embodiments of the utility model described and illustrated below are presented for illustrative purposes and not as a limitation of the exemplary embodiments of the utility model to the instances shown herein. Those skilled in the art will find, or using routine experimentation, be able to determine a greater or lesser number of equivalents to the particular embodiment of the utility model specifically described herein.

Figure 1 shows a diagram of a device 1 for managing the waste heat of a solar photovoltaic panel 2. An absorber 3 consisting of a homogenizing plate 4 and a heat exchanger 5 is connected to the underside of the solar photovoltaic panel 2. The homogenizing plate 4 is made of thick aluminum sheet and is attached to the solar photovoltaic panel 2 by a thermally conductive paste to create the largest possible transmission surface. The thermally conductive paste must be made of an inert material to avoid stresses between the solar photovoltaic panel 2 and the glued homogenizing plate 4. In addition, the thermally conductive paste must meet the condition of being inert to the processing of the back surface of the solar photovoltaic panel 2.

The heat exchanger 5 is shaped as a hollow body for the flow of a liquid heat transfer medium, for example an alcohol-based medium. The liquid heat transfer medium must not be aggressive to metals, must be antifreeze and be environmentally friendly. The heat exchanger 5 is made, for example, of steel with an enamel coating. A thermally conductive paste is applied between the heat exchanger 5 and the homogenizing plate 4. The heat exchanger 5 is connected to the first circuit of the heat pump 6, which serves as a pump to remove waste heat for additional use. The difference from the heat pump 6 is that it uses a vacuum expansion vessel 11 connected to the first loop. The housing of the vacuum expansion vessel 11 has a switching function when expanding the balloon, unlike the prior art.

The gas medium is blown inside the balloon and the liquid heat transfer medium is fed into the space between the walls of the vacuum expansion vessel 11. In the first circuit, a water storage tank 10 is connected, which serves as a thermal buffer for sudden changes in air temperature. The heat pump 6 can also operate in reverse mode, in which the solar photovoltaic panels 2 can be heated by the absorber 3, for example, to defrost the panels.

In the event that the device is intended to work in the so-called island mode, in which it is completely independent of an external artificial energy source, the device 1, in addition to all the above-mentioned elements, also includes a storage of electrical energy 12, such as a Li-Ion battery. The electrical energy storage 9 is electrically connected to the solar photovoltaic panels 2 to charge them with electricity and is also connected to the heat pump 6 to supply it with energy. The capacity of the electrical energy storage 12 increases depending on the number of solar photovoltaic panels 2 and the related size of the device 1.

Figure 2 shows a bottom view of the solar photovoltaic panel 2. The homogenizing plate 4 of the absorber 3 does not cover the entire lower side of the solar photovoltaic panel 2, but leaves a free strip at the lower end of the solar photovoltaic panel 2 for access. A heat collector 7 is located on this strip, which consists of an aluminum housing. The heat collector 7 has a volume equal to that of the homogenizing plate 4, in relation to the volume of the material. At the same time, a Peltier cell 8 with the hot side is located on the homogenizing plate 4. The cold side of the Peltier cell 8 is equipped with the output of a copper heat-conducting transition 9. The heat collector 7 is equipped with the output of the heat-conducting transition 9.

Figure 3 shows the air flow under the solar photovoltaic panels 2 fixed on the sloping roof of the site. By orienting the hot heat collectors 7 towards the lower edge of the solar photovoltaic panels 2, the chimney air flow is initiated in the space between the solar photovoltaic panels 2 and the roof.

Industrial applicability

The solar photovoltaic panel waste heat management device, according to the utility model, will be applied to newly installed or already installed solar panels, residential buildings, industrial sites or solar power plants.

List of designating positions used in the drawings

1. Device for managing the waste heat of solar photovoltaic panels

2. Solar photovoltaic panel

3. Absorber

4. Homogenizing plate

5. Heat exchanger

6. Heat pump

7. Heat collector

8. Peltier cell

9. Heat-conducting transition

10. Storage tank

11. Vacuum expansion vessel

12. Storage of electrical energy

Claims (2)

A device for controlling the waste heat of solar photovoltaic panels, comprising at least one absorber located on the underside of at least one solar photovoltaic panel for absorbing waste heat, wherein at least one heat exchanger is connected to the first circuit of the heat pump and at least one cell of Peltier is connected to the absorber with the heating and cooling side to generate electricity, characterized in that the absorber includes a homogenizing plate (4) located on the back of the solar photovoltaic panel (2), at least one heat exchanger (5) is connected to the free side of the homogenizing plate (4) and the homogenizing plate (4) partially covers the rear side of the solar photovoltaic panels (2), additionally between the rear side of the solar photovoltaic panel (2), the homogenizing plate and the heat exchanger (5) -hardening, heat-conducting paste, whereby to the uncovered part of the back side of the solar f At least one heat collector (7) with at least one thermally conductive transition (9) is located in the otvoltaic panel (2), and the Peltier cell (8) is applied with the heating side to the homogenizing plate (4) and with the cooling side to the thermally conductive transition (9). ) A device for controlling the waste heat of solar photovoltaic panels, comprising at least one absorber located on the underside of at least one solar photovoltaic panel for absorbing waste heat, wherein at least one heat exchanger is connected to the first circuit of the heat pump and at least one cell Peltier is connected to the absorber with the heating and cooling side to generate electricity, characterized in that the absorber (3) includes a homogenizing plate (4) located on the back of the solar photovoltaic panel (2), as at least one heat exchanger 5) is connected to the free side of the homogenizing plate (4) and the homogenizing plate (4) partially covers the rear side of the solar photovoltaic panels (2), additionally between the rear side of the solar photovoltaic panel (2), the homogenizing plate (4) and the heat exchanger (5) has a layer of non-hardening, thermally conductive paste, whereby to the uncovered part of the back side of the salt The photovoltaic panel (2) has at least one heat collector (7) with at least one thermally conductive transition (9), and the Peltier cell (8) is applied with the heating side to the homogenizing plate (4) and with the cooling side to the thermally conductive transition. 9), wherein the device includes at least one electrical storage (12) connected to the solar photovoltaic panels (2), the heat pump (6) being simultaneously connected to the solar photovoltaic panel (2) and to the electrical storage (12). )