RU2377696C1 - Concentrator photovoltaic module - Google Patents

Abstract

FIELD: physics; semiconductors.

SUBSTANCE: invention can be used in land-based solar power plants based on linear solar radiation concentrators designed for stand-alone electrical power supply systems in different climatic zones. A concentrator photovoltaic module is proposed, which is a sealed container which contains linear Fresnel lenses, a series of photodetectors and hollow tubes which link the sealed container with the surrounding atmosphere. The tubes are filled with atmospheric moisture sorbent, and their surfaces lie at the focus of auxiliary linear Fresnel lenses.

EFFECT: protection of the concentrator photovoltaic module based on linear Fresnel lenses from atmospheric moisture, which in turn ensures stability of electrophysical and optical characteristics of the module.

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Description

The invention relates to the field of solar energy and, in particular, to photovoltaic modules. Most successfully, the present invention can be applied in terrestrial solar power plants based on linear solar concentrators intended for autonomous power supply systems in various climatic zones.

It is known that the use of solar radiation concentrators, subject to matching the parameters of the concentrator with the parameters of solar cells, can increase the efficiency of photovoltaic modules and improve their economic performance by reducing the consumption of expensive semiconductor materials [1].

A known photovoltaic module with linear concentrators of solar radiation, the photodetector chains of which are protected from the environment by a transparent sealant layer based on polymers [2].

The module is a metal rectangular case with a transparent glass cylindrical cover (reflector). At the bottom of the housing, chains of photodetectors are located on the opposite side from the reflector. To protect against external atmospheric influences, linear concentrators of solar radiation (Fresnel lenses) are formed on the surface of the reflector opposite from incident light radiation, and effective heat removal from photodetectors is provided by heat removal through a heat-conducting dielectric pad between the body and photodetectors.

The disadvantage of this design is the leakage of the volume of the photovoltaic module from the surrounding space. Therefore, when changing the temperature and weather conditions in the volume of the photovoltaic module, condensation of atmospheric moisture vapor can occur. This prevents the effective conversion of solar radiation into electrical energy, at least until the temperature in the internal volume of the module exceeds the dew point temperature of water vapor. The presence of moisture in the volume of the photovoltaic module also negatively affects the operation of the optical elements of the module and causes corrosion of the housing and metal elements of the module, which reduces the life of the photodetectors.

The closest in technical essence and the achieved result is a photovoltaic module containing a housing of interconnected glass sheets glued with sealant, linear Fresnel lenses, a chain of photodetectors and a gateway device connecting the internal volume of the module with the external environment [3].

The module consists of the main volume, in which Fresnel silicone lenses are located, and specially formed compartments, which are sealed and transparent to light, in which the photodetector chains are located. Fresnel lenses are formed on the back of the glass surface, perpendicular to the solar light flux. The luminous flux is concentrated on the surface of the photodetectors located in the sealed compartments of the module, made of flat glass fragments glued with glue-sealant. Photodetectors through a dielectric heat-conducting gasket are mounted on a heat sink based on a metallized textolite with the corresponding electrical wiring.

The air from the sealed compartments is evacuated to protect the photodetectors from the effects of the external atmosphere, the main volume of the photoelectric module through the gateway devices (hollow tubes) is connected to the external atmosphere, because it cannot be pumped out due to possible structural deformations with significant temperature fluctuations in the internal air volume.

The disadvantages of this design include the following:

- since the volume of the module is connected to the atmosphere through a gateway device, protection of this volume from moisture and dust is not provided. In the particular case, even if you fill the hollow tubes with filter material (for example, silica gel granules or a similar moisture-absorbing substance), you can only provide one-time protection against moisture, since the module’s design does not provide for the possibility of regeneration of the moisture-absorbing substance;

- sealed compartments, the air from which is evacuated, still contain a residual amount of moisture, and with significant temperature fluctuations due to the operation of the module itself, moisture condensation may occur on the surface of solar cells;

- the complexity of the design of the module, significantly limiting its functionality and maintainability.

The design of photovoltaic modules with solar concentrators should ensure its long-term operation in real operating conditions. Given that the field of application of photovoltaic modules is natural environmental conditions, it is necessary to protect the optical system, photodetectors and electrical contacts from the effects of temperature and pressure fluctuations, wind, dust, and above all, from high humidity.

The objective of the invention is to protect the concentration of the photovoltaic module based on linear Fresnel lenses from atmospheric moisture.

This is achieved due to the fact that in the known concentrator photoelectric module containing linear Fresnel lenses, a chain of photodetectors and hollow tubes communicating with the external atmosphere, tubes (for example, metal) filled with atmospheric moisture sorbent are used to protect the module’s volume from atmospheric moisture. The tubes are located parallel to the photodetector chains near the side walls of the module, which are heated by additional concentrators of solar light flux based on linear Fresnel lenses located nearby and parallel to the main Fresnel linear lenses, which serve as solar radiation concentrators on the surface of the photodetectors.

The use of this design solution provides isolation of the photovoltaic module from dust and moisture. When the module temperature is lowered in the evening and night hours, moisture does not condense on the optical surfaces of the Fresnel lenses, as well as on the surfaces of the photoelectric elements protected by a silicone film or on the side walls of the module due to the high adsorption ability of the sorbent to absorb the moisture in the volume of the module. In bright sunlight, the temperature of the module, in particular the chain of photodetectors and tubes containing sorbent, increases. In this case, the degree of desorption of water vapor from the sorbent material significantly increases under the action of concentrated light radiation from additional Fresnel lenses.

Under the influence of increased air pressure in the volume of the module, the released water vapor is pushed into the air space surrounding the module during operation of the module in conditions of intense sunlight. Thus, in the inventive device eliminates the process of condensation of water vapor in the volume of the photovoltaic module under changing temperature conditions.

The solutions to a similar problem known in science and technology have not found the use in PV modules based on linear Fresnel lenses of a method of protecting the module’s internal volume from atmospheric moisture using tubes connecting the module’s volume with the surrounding atmosphere and filled with atmospheric moisture sorbent, and the module’s design ensures the regeneration of moisture-absorbing substances in the tubes.

The invention is illustrated in the drawing, which schematically shows the claimed design of the module, where:

1 - the main linear Fresnel lenses;

2 - chains of photodetectors;

3 - additional Fresnel lenses;

4 - hollow tubes;

5 - moisture-absorbing substance (sorbent);

6 - tube end located in the internal volume of the module;

7 - the end of the tube located outside the internal volume of the module;

8 - case;

9 - glass cover;

10 - concentrated solar radiation;

11 is a dielectric heat-conducting layer.

Regions 1 denote the main linear Fresnel lenses concentrating solar radiation 10 on the surface of the photodetector chain 2. Regions 3 denote additional linear Fresnel lenses concentrating part of the solar radiation on the surface of the tube 4 with sorbent 5, connecting the module volume through ends 6 with the surrounding space through ends 7 .

The main Fresnel lenses 1 are made of silicone on a glass base 9. In the same way, additional Fresnel lenses 3 are located next to the main lenses. The photodetector chains 2 are located on the metal base of the housing 8, but are isolated from it by a heat-conducting dielectric layer 11. All solar cells are connected in series, and the electrical leads are led out through insulated terminals on the side surface of the module.

Additional Fresnel lenses are made in such a way that they concentrate the solar light flux on tubes containing sorbent. The tubes themselves have a blackened surface for maximum ability to absorb concentrated light rays 10 to ensure effective desorption of water vapor from the sorbent by increasing the temperature of the tube under the influence of intense light flux. As a sorbent, any moisture-absorbing substance (for example, silica gel) with a regeneration temperature of 45 ÷ 100 ° C can be used. The module housing 8 is made of metal (for example, aluminum) for efficient heat removal from solar cells and has a rigid structure to ensure accurate focusing of the light flux on the surface of the photodetector chain and the surface of the tubes of the gateway device.

An example of a specific implementation.

The concentrator photovoltaic module is a body 8 in the form of a metal rectangular container and a glass cover 9 glued with glue-sealant made of 2 mm thick tempered PILKINTON glass with a transparency coefficient (in the wavelength range from 0.3 to 1.2 μm) not less than 96%. On the inner surface of the glass lid 9, the main 1 and additional 3 linear Fresnel lenses are made of silicone of the ELASTOSIL brand RT-604. The chains of photodetectors 2, which are commutated standard silicon solar cells, are located on the heat-conducting base 11. The length of each chain of cells is 500 mm, the width is 10 mm.

The tubes 4 of the gateway device are made of aluminum with a blackened outer surface to reduce heat loss due to re-radiation. KS-Trokenperlen silica gel was placed inside the tubes (specific heat - 1 KJ / kg × K, thermal conductivity - 0.2 W / m × K, average granule size - 3.5 mm).

The tubes are made collapsible (end parts 7 and 6 are screwed into the tube after filling it with silica gel). The tubes are fixed inside the module using a threaded connection made in the wall 8. To fix the silica gel in the volume of the tubes, metal grids with a cell of 1.0 × 1.0 mm are used, which are fixed from the ends 7 and 6 when assembling the filled tube.

The regeneration of the used silica gel takes place at a temperature of 90 ° C, which is ensured by heating the tubes with additional Fresnel lenses.

The dew point of water vapor inside the module under conditions of full solar exposure, measured by a portable microprocessor meter of microhumidity 1.9 IVG-1 K-P, is not higher than minus 75 ° C.

Thus, a concentrator photovoltaic module containing hollow tubes filled with a regenerable moisture-absorbing substance (for example, silica gel) can completely eliminate moisture condensation on the parts of the internal volume of the module, which ensures the stability of the electrophysical and optical characteristics of the module.

The inventive version of the photovoltaic module is simple in design, not subject to dust and moisture, which ensures long-term operation of the module in places with high humidity and with changing temperature weather conditions over a wide range.

Information sources

1. J.I. Alferov, V.M. Andreev, V.D. Rumyantsev. Trends and prospects for the development of solar photovoltaics. - Journal "Physics and Technology of Semiconductors", 2004, Volume 38, Issue 8, pp. 937-948.

2. US Patent, IPC: H01L 31/052, No. 5,505,789.

3. WIPO patent, IPC: H01L 31/052, No. WO 2006/049524 - prototype.

Claims (1)

A concentrator photovoltaic module, which is a sealed volume, containing linear Fresnel lenses, a chain of photodetectors and hollow tubes connecting the sealed volume to the surrounding atmosphere, characterized in that the tubes are filled with atmospheric moisture sorbent, and their surfaces are located in the focus of additional linear Fresnel lenses.