US-12627256-B2 - Device and method for sunlight-based power generation

US12627256B2US 12627256 B2US12627256 B2US 12627256B2US-12627256-B2

Abstract

The present invention relates to an energy generation device ( 1 ) comprising a reflection panel ( 11 ) presenting a reflecting surface, an energy generation module ( 12 ) and a holding structure ( 13 ) holding the reflection panel ( 11 ) and the energy generation module ( 12 ) together, wherein the reflection panel ( 11 ) is configured to filter an incident sunlight thereby letting a first portion of said sunlight pass through it and reflecting a second portion of said sunlight, characterized in that said reflecting surface presents a plurality of reflective regions ( 11′, 11″, 11 ′″) differently oriented with respect to each other and each being configured to homogeneously reflect said second portion of incident light on a collecting surface of said energy generation module ( 12 ).

Inventors

Jonas Roch
Dominik Blaser

Assignees

VOLTIRIS SA

Dates

Publication Date: 20260512
Application Date: 20220719
Priority Date: 20210728

Claims (12)

1 . An energy generation device comprising a reflection panel presenting a reflecting surface, an energy generation module, and a holding structure holding the reflection panel and the energy generation module together, wherein the reflection panel is configured to filter an incident sunlight thereby letting a first portion of said sunlight pass through the reflection panel and reflecting a second portion of said sunlight, characterized in that said reflection panel is a single piece panel comprising a plurality of differently oriented adjacent reflective lamellas, wherein a position and an orientation of each lamella of said plurality of differently oriented adjacent reflective lamellas is based on a length and a tilt angle of the energy generation module, a distance between the lamella and the energy generation module, and a size and orientation angle of a neighbor lamella such that each lamella homogeneously focuses said second portion of incident light on a collecting surface of said energy generation module, wherein the holding structure connects the reflection panel to the energy generation module such that the reflection panel reflects light onto the energy generation module at a fixed angle.
2 . The energy generation device according to claim 1 , wherein: the reflection panel comprises a material having a transmission index, a reflection index, or a refraction index, and the transmission index, the reflection index, or the refraction index are tuned to let pass light with a specific wavelength range.
3 . The energy generation device according to claim 1 , wherein the reflection panel comprises specific materials and/or specific thickness ranges and/or specific surface treatments and/or specific additive for tuning a transmission index, a reflection index, or a refraction index of the reflection panel.
4 . The energy generation device according to claim 1 , further comprising an orientation system adapted to modify an orientation of the reflection panel.
5 . The energy generation device according to claim 4 , characterized in that the orientation system comprises a tilting module and a pivot module adapted to modify the orientation of the reflection panel in two directions perpendicular to each other.
6 . The energy generation device according to claim 1 , further comprising a sun tracking system adapted to determine a sun orientation/position or/and a sunlight direction.
7 . The energy generation device according to claim 6 , further comprising: an orientation system adapted to modify an orientation of the reflection panel, and a control system adapted to control the orientation system on a basis of data received by the sun tracking system.
8 . The energy generation device according to claim 1 , characterized in that the reflective lamellas are flat and/or adjacent surfaces.
9 . The energy generation device according to claim 1 , characterized in that the reflection panel is a dichroic mirror made of at least a facet.
10 . The energy generation device according to claim 1 , characterized the energy generation module is selected from the group consisting of an electricity generation module using photovoltaic cells, a module for heat generation, and a module for hydrogen production.
11 . The energy generation device according to claim 1 , characterized a backside of the energy generation module presents a reflective surface, a light scatterer, contains fluorescent materials, and/or is an energy-generating surface.
12 . An energy generation system comprising a plurality of energy generation devices according to claim 1 , further comprising one or several beams each holding a plurality of devices from a bottom part of the plurality of devices and/or cables hanging the energy generation devices from a top of the plurality of devices.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application is a U.S. National Stage under 35 U.S.C. § 371 of PCT/EP2022/070257 filed Jul. 19, 2022, which depends from and claims priority to European patent application number 21188265.9 filed Jul. 28, 2021, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD The present invention relates to the field of sunlight-based power generation and more particularly to the field of sunlight-based power generation in agriculture. The present invention aims at providing a means for both power generation and agriculture growth optimization. BACKGROUND OF THE ART Nowadays, Photovoltaic (PV) power generation is seen as a green and low-cost source of energy world-wide as well as a key element paving the way to a fossil energy-free future. However, finding space for large PV projects remains challenging because by creating a PV field, one may either waste arable land or hurt biodiversity. For this reason, modern projects commonly called “Agrovoltaics” have been created which aim at promoting a double use of available land, in which a field of arable land could simultaneously be used for power generation as well as agricultural yield. Two different approaches have been considered so far for agrovoltaics which are called partial shading and spectral filtering. In the partial shading approach, semi-transparent, not particularly wavelength-selective, or opaque photovoltaic cells are placed above the field where the plants are growing and generate electricity while creating a partial shading on the plants by absorbing a portion of the light reaching the plants. The shading is characterized by a decrease in the light intensity but does not modify the spectral components of sunlight. At northern latitudes, where sunlight is scarce in the winter half-year, the partial shading approach, as described for instance in US2017126172A1, is not applicable to all plant types. In the low light conditions of the winter half, reducing the amount of sunlight reaching the plants can be detrimental to the growth of some specific light-loving plant varieties. In some designs, for instance as in EP3798688A1, the transmission of the panels can be tuned to let more light reach the plants. However, when the transmission reaches 100%, no electricity generation can be performed without hindering plants growth. For this reason, the equilibrium between electricity generation and plant's growth may be very complicated to obtain. On the other hand, the spectral filtering approach differs radically from the previous approach, as one uses special PV panels wherein only a set of selected wavelengths will be allowed to reach the plants. In this solution, a colored filter (dichroic filter) or a wavelength-selective type of PV cell is used to separate the light components benefitting plant's growth from the rest of the solar spectrum. Those wavelengths not useful for plant's growth are then used for energy generation (PV or heat concentration). The advantage of the spectral filtering approach is that independently of the light conditions, plants will receive the same amount of light necessary for their growth as if there was no spectral filtering. In turn, even in the months with low insolation, the PV system will generate electricity with a similar efficiency as in the sunnier months. In the spectral filtering approach, the use of wavelength-selective semi-transparent solar cells has been investigated (for instance in US2012198763A1). However, the light transmission of these solar cells has to date never reached transmission as high as thin-films filters, hence also creating a partial shading detrimental to plant's growth and the photon-electron efficiency has remained rather low. In addition, in recent years, thin-film dichroic filters have been already used in a variety of setups within the domain of agrovoltaics, for example in WO2016093397A1 presents a system with a separation between the focusing optics and the spectral separation. However, by adding optical elements to the system, the system is harder to clean, creates additional interfaces in the light path and hence decreases the overall efficiency. As thin-film filters have their bandwidth inherently dependent on the light's angle of incidence, systems with fixed orientation given by external factors (e.g. greenhouse orientation, choice of roof-like structure orientation, latitude . . . ), such as in WO2021012003A1, CN106538294A, FR3019885A1 or WO2015158968A1 will need a redesign of the filter depending on the geometry of the setup. WO2017024974A1 presents another conventional system which is a Cassegrain system where the light useful for plants' growth is reflected by the primary and secondary mirrors to reach the plants. Such a system has a finite aperture and only mostly direct light can get to the crops. On a cloudy day, the light intensity reaching the plants would be decreased significantly. Moreover, manufacturing a la