WO2012032431A2 - Arrangement for light energy conversion - Google Patents

Arrangement for light energy conversion Download PDF

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Publication number
WO2012032431A2
WO2012032431A2 PCT/IB2011/053751 IB2011053751W WO2012032431A2 WO 2012032431 A2 WO2012032431 A2 WO 2012032431A2 IB 2011053751 W IB2011053751 W IB 2011053751W WO 2012032431 A2 WO2012032431 A2 WO 2012032431A2
Authority
WO
WIPO (PCT)
Prior art keywords
light
dichroic filter
arrangement
energy
opening
Prior art date
Application number
PCT/IB2011/053751
Other languages
French (fr)
Other versions
WO2012032431A3 (en
Inventor
Eduard Johannes Meijer
Hendrikus Hubertus Petrus Gommans
Original Assignee
Koninklijke Philips Electronics N.V.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Koninklijke Philips Electronics N.V. filed Critical Koninklijke Philips Electronics N.V.
Publication of WO2012032431A2 publication Critical patent/WO2012032431A2/en
Publication of WO2012032431A3 publication Critical patent/WO2012032431A3/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
    • F21S9/00—Lighting devices with a built-in power supply; Systems employing lighting devices with a built-in power supply
    • F21S9/02—Lighting devices with a built-in power supply; Systems employing lighting devices with a built-in power supply the power supply being a battery or accumulator
    • F21S9/03—Lighting devices with a built-in power supply; Systems employing lighting devices with a built-in power supply the power supply being a battery or accumulator rechargeable by exposure to light
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
    • F21S11/00—Non-electric lighting devices or systems using daylight
    • F21S11/007—Non-electric lighting devices or systems using daylight characterised by the means for transmitting light into the interior of a building
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
    • F21S19/00—Lighting devices or systems employing combinations of electric and non-electric light sources; Replacing or exchanging electric light sources with non-electric light sources or vice versa
    • F21S19/005—Combining sunlight and electric light sources for indoor illumination
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H01L31/054—Optical elements directly associated or integrated with the PV cell, e.g. light-reflecting means or light-concentrating means
    • H01L31/0549—Optical elements directly associated or integrated with the PV cell, e.g. light-reflecting means or light-concentrating means comprising spectrum splitting means, e.g. dichroic mirrors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V14/00—Controlling the distribution of the light emitted by adjustment of elements
    • F21V14/08—Controlling the distribution of the light emitted by adjustment of elements by movement of the screens or filters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V23/00—Arrangement of electric circuit elements in or on lighting devices
    • F21V23/04—Arrangement of electric circuit elements in or on lighting devices the elements being switches
    • F21V23/0442—Arrangement of electric circuit elements in or on lighting devices the elements being switches activated by means of a sensor, e.g. motion or photodetectors
    • F21V23/0464—Arrangement of electric circuit elements in or on lighting devices the elements being switches activated by means of a sensor, e.g. motion or photodetectors the sensor sensing the level of ambient illumination, e.g. dawn or dusk sensors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
    • F21Y2115/00—Light-generating elements of semiconductor light sources
    • F21Y2115/10—Light-emitting diodes [LED]
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/52—PV systems with concentrators

Definitions

  • the present invention relates in general to a daylight harvesting system, and in particular to an arrangement for light energy conversion in such a daylight harvesting system.
  • Photovoltaic elements receiving daylight have been used to generate electricity. This electricity may inter alia be used to power artificial light sources.
  • This electricity may inter alia be used to power artificial light sources.
  • Some of the aspects of daylight that people prefer are lost. These aspects may include the broad spectrum, which yields light with a high color rendering index, the omnipresence of daylight, because 50 % of the daylight is diffuse light, the dynamics during the day in terms of color and direction, as well as the fact that daylight may be regarded as a highly collimated large area light source. All these aspects cannot be efficiently reproduced with artificial light sources.
  • An undesired aspect of daylight however is that, due to the broad spectrum which extends into the far infrared part of the spectrum, also often undesired heat is allowed into the building through direct daylight systems.
  • the dynamic aspect of daylight can make it difficult to ensure a certain minimum level of light in the building at all times, thus requiring artificial light sources to replenish the daylight if needed, in an efficient way. It is an object of the present invention to overcome these problems, and to provide an improved lighting system that retains the desirable aspects of daylight and uses the non-visible part of the solar spectrum for light energy conversion.
  • the inventors of the disclosed embodiments have discovered that all the desirable aspects of daylight can be retained, whilst the infrared part of the collected daylight is received by an energy converting element thereby preventing heat exchange with the area to be illuminated.
  • the thermal radiation part of the solar spectrum i.e. light from the infrared range of the spectrum
  • the generated energy can be used to power artificial light sources that can replenish the daylight, inter alia if the daylight levels are considered to be too low. It is an object of the present invention to provide such an arrangement.
  • an arrangement for light energy conversion the arrangement having a first opening arranged to receive incident light entering the arrangement and a second opening arranged to emit output light from the arrangement, the arrangement comprising: at least one energy converting element arranged to convert light energy to electrical energy, and at least one first dichroic filter arranged to receive light from the first opening, to transmit visible light and to reflect infrared light, the at least one first dichroic filter being positioned such that received visible light is transmitted towards the second opening and such that received infrared light is reflected towards the at least one energy converting element.
  • Such an arrangement may provide an integrated solar light tube that transmits the visible part of the solar spectrum and captures the infrared part of the solar spectrum with the energy converting element. This has a twofold advantage. Firstly the heat associated with the received light is kept isolated from the area to be illuminated.
  • the arrangement further comprises at least one second dichroic filter arranged to receive light from at least one of the first opening and the at least one first dichroic filter, wherein the at least one second dichroic filter is in relation to the first opening positioned in front of the at least one energy converting element such that visible light received by the at least one second dichroic filter is reflected towards the at least one first dichroic filter and infrared light received by the at least one second dichroic filter is transmitted towards the at least one energy converting element.
  • the at least one second dichroic filter reflects visible light towards the at least one first dichroic filter (which transmits visible light), advantageously this enables an increased amount of visible light to be outputted from the arrangement.
  • the arrangement further comprises at least one second dichroic filter arranged to receive light from the first opening, to reflect visible light and to transmit infrared light, wherein the at least one second dichroic filter is in relation to the first opening positioned in front of the at least one first dichroic filter such that visible light received by the at least one second dichroic filter is reflected towards the at least one energy converting element, thereby enabling both visible light and infrared light to be reflected towards the at least one energy converting element.
  • Such an arrangement enables a large portion of the received incident light at all wavelengths to be refiected towards and received by the energy converting element, thereby increasing the amount of energy to be converted.
  • At least one of the at least one first dichroic filter and/or the at least one second dichroic filter is mechanically movable.
  • this enables the arrangement to be switched between different energy conversion configurations.
  • the energy converting element may receive both infrared and visible light
  • the energy converting element may receive exclusively either infrared or visible light
  • the energy converting element may receive neither infrared nor visible light.
  • the arrangement further comprises an LED array, the LED array being powered with energy from the at least one energy converting element.
  • the arrangement further comprises a light sensor arranged to sense flux of incident light received by the arrangement, the light sensor being arranged such that the LED array is powered with energy from the energy storing element if and only if the sensed flux is below a predetermined threshold.
  • artificial light such as light emitted by a LED array
  • the arrangement may be also provided with LEDs to add illumination if the received daylight is not providing enough light to illuminate the area to be illuminated. For example, the LEDs may be powered in the evening using the electricity that was generated by the energy converting element by the received daylight.
  • a luminaire comprising an arrangement as disclosed above.
  • an anidolic integrated light system comprising an arrangement as disclosed above.
  • Figs. 1-8 illustrate arrangements for light energy conversion according to embodiments.
  • Figs. 9a-9b illustrate filter responses for dichroic filters according to embodiments.
  • Fig. 1 illustrates an arrangement la for light energy conversion according to an embodiment.
  • the arrangement la may be (part of) a solar tube.
  • the arrangement la may also be part of a luminaire.
  • the arrangement la comprises at least one energy converting element 5a, 5b and at least one first dichroic filter 7a, 7b.
  • the arrangement la has a first opening 12a and a second opening 12b.
  • Incident light 2a, 2b ⁇ inter alia in the form of daylight from the sun) is received at the first opening 12a and output light is emitted from the arrangement 1 at the second opening 12b.
  • the first opening 12a and the second opening 12b may thus be said to be positioned along a light axis 16.
  • the incident light 2a, 2b comprises visible light and infrared light of the light spectrum.
  • visible light may be defined as light having a wavelength shorter than 800 nm.
  • Infrared light may be defined as light having a wavelength longer than 800 nm.
  • Fig. 1 the infrared part of the incident light 2a, 2b is illustrated by solid lines.
  • visible light is illustrated by dotted, dash-dotted and dashed lines.
  • the incident light Upon entering the arrangement la at the first opening 12a the incident light is received by the at least one first dichroic filter, in Fig. 1 illustrated by two dichroic filters 7a, 7b.
  • the sunlight first hits a dichroic filter, that is positioned under an angle with respect to the axis of the incident light, in order to reflect the light with a wavelength longer than 800 nm (the infrared light) towards the at least one energy converting element, and to transmit the light with a wavelength shorter than 800 nm (the visible light).
  • the at least one first dichroic filter 7a, 7b is arranged to receive light 2a, 2b from the first opening 12a and to transmit visible light (towards the second opening 12b) and to reflect infrared light (towards the at least one energy converting element 5a, 5b).
  • the at least one first dichroic filter 7a, 7b is thus positioned such that received visible light is transmitted towards the second opening 12b and such that received infrared light is reflected towards the at least one energy converting element 5a, 5b.
  • the at least one first dichroic filter 7a, 7b may be arranged between the first opening 12a and the second opening 12b at an angle a larger than 0 degrees and smaller than 90 degrees, preferably 45 degrees, with respect to the light axis 16.
  • the infrared portion of the incident light is thus received by the at least one energy converting element 5a, 5b which is arranged to convert light energy to electrical energy.
  • the at least energy converting element 5a, 5b may comprise one or more
  • the at least energy converting element 5a, 5b may comprise a photo-luminescent concentrator connectable to a solar cell.
  • the photo-luminescent concentrator then converts the light to longer wavelengths and guides it to a solar cell that is then mounted to the side of the photo-luminescent concentrator plate.
  • first dichroic filters 7a, 7b are illustrated in Fig. 1 the arrangement la may, depending on the configuration of the arrangement la, have two or more first dichroic filters 7a, 7b. The disclosed embodiment are not limited to a particular number of first dichroic filters.
  • energy converting elements 5a, 5b are illustrated in Fig. 1.
  • the arrangement la may have two or more energy converting elements 5a, 5b.
  • the disclosed embodiment are not limited to a particular number of energy converting elements. According to embodiments the number of first dichroic filters 7a, 7b may be the same as the number of energy converting elements 5 a, 5b.
  • Fig. 2 illustrates an arrangement lb for light energy conversion according to an embodiment.
  • the arrangement lb in Fig. 2 is similar to the arrangement la in Fig. 1 as disclosed above.
  • the arrangement lb thus has a first opening 12a wherein incident light 2a, 2b is received and a second opening 12b from which output light is emitted.
  • Incident light is received by at least one first dichroic filter 7a, 7b which is arranged to reflect infrared light towards at least one energy converting element 5 a, 5b and to transmit visible light towards the second opening 12b.
  • the at least one energy converting element 5 a, 5b is thus arranged to convert the received infrared light into electrical energy.
  • the inner walls of the arrangement lb may be provided with a reflective surface being highly reflective for all wavelengths of light to allow light at all wavelengths to be efficiently reflected through the arrangement lb.
  • the at least one energy converting element 5a, 5b may be arranged on the light reflective sidewalls.
  • the arrangement lb may further comprise a light collecting dome 3.
  • the light collecting dome 3 is positioned at the first opening 12a. As the collecting dome 3 collects and redirects incident light 2a, 2b into the arrangement lb there is no need for weather protection covers to be integrated on top of the at least one energy converting element 5 a, 5b. Wear may thereby be minimized as the at least one energy converting element 5a, 5b is integrated inside the arrangement lb (which may be in a building structure, see Fig. 8). Particularly the collecting dome 3 may be arranged to collimate the entering incident light 2a, 2b towards the at least one first dichroic filter 7a, 7b.
  • the arrangement lb may further comprise a diffuser 11. The diffuser 11 is positioned at the second opening 12b.
  • the diffuser 11 is arranged to receive visible light from the at least one first dichroic filter 7a, 7b and to emit output light from the arrangement lb.
  • the diffuser 11 may thereby enable the output light in a desired direction.
  • the diffuser 11 is but one example of elements or devices which may be attached to the second opening 12b. As the skilled person understand additional filters, collimators, and the like may be equally provided at the second opening 12b in order to provide a specified light effect.
  • LEDs 9a, 9b, 9c, 9d, 9e, 9f may be comprised in the arrangement lb to compensate for reduced solar lighting (e.g. due to clouds, or at night).
  • the power generated by the at least one energy converting element 5 a, 5b can be used to drive these LEDs.
  • the arrangement lb may thus further comprise an energy storing element 8 arranged to store electrical energy received from the at least one energy converting element 5 a, 5b.
  • the LED array may then be powered with energy from the at least one energy converting element 5 a 5b or with energy stored in the energy storing element 8.
  • Dimming may generally be provided by inserting a light reflecting or absorbing plate in the light collecting dome 3 that as a result would lead to spectral waste of the already collected solar radiation.
  • the arrangement lb may further comprise a light sensor 4.
  • the light sensor 4 may be arranged to sense flux of incident light received by the arrangement lb.
  • the light sensor 4 may be operatively connected to a switch 10 positioned between the energy storing element 8 and the one or more LEDs 9a, 9b, 9c, 9d, 9e, 9f. The position of the switch may be determined by the sensed flux of incident light.
  • the light sensor 4 may be arranged such that the switch enables a current to be established between the energy storing element 8 and the one or more LEDs 9a, 9b, 9c, 9d, 9e, 9f if and only if the sensed flux of incident light is below a predetermined threshold, thereby enabling the one or more LEDs 9a, 9b, 9c, 9d, 9e, 9f to provide artificial light.
  • the light sensor 4 may thereby be arranged such that the LED array is powered with energy from the energy storing element 8 if and only if the sensed flux is below a predetermined threshold.
  • the arrangement lb may further comprise at least one second dichroic filter
  • the arrangement lb may have two or more second dichroic filters 6a, 6b.
  • the disclosed embodiment are not limited to a particular number of second dichroic filters. According to embodiments the number of second dichroic filters 6a, 6b may be the same as the number of energy converting elements 5a, 5b.
  • the at least one second dichroic filter 6a, 6b may be located over the surface area of the at least one energy converting element 5 a, 5b.
  • the at least one second dichroic filter may be arranged to receive light from at least one of the first opening 12a as well as from the at least one first dichroic filter 7a, 7b.
  • the at least one second dichroic filter 6a, 6b may, in relation to the first opening 12a, be positioned in front of the at least one energy converting element 5 a, 5b such that visible light received by the at least one second dichroic filter 6a, 6b is reflected towards the at least one first dichroic filter 7a, 7b and infrared light received by the at least one second dichroic filter 6a, 6b is transmitted towards the at least one energy converting element 5a, 5b.
  • the at least one second dichroic filter 6a, 6b may thus be arranged to reflect light having a wavelength shorter than 800 nm.
  • the at least one second dichroic filter 6a, 6b may be arranged to transmit light having a wavelength longer than 800 nm.
  • the at least one second dichroic filter 6a, 6b is thus arranged to reflect visible light and to transmits infrared light, such that it can be absorbed by the at least one energy converting element 5 a, 5b. This is done, because the sunlight can enter the dome 3 under all kinds of angles and the visible light should be guided into the building (i.e. be outputted from the second opening 12b of the arrangement lb, see also Fig. 8) and not be absorbed by the at least one energy converting element 5 a, 5b. As noted above the power generated in the at least one energy converting element 5 a, 5b can be stored in an energy storing element 8 for later use.
  • the arrangement la By repositioning the at least one second dichroic filter 6a, 6b the arrangement la, lb can be switched to collect all the incident light onto the at least one energy converting element 5 a, 5b. This increases the electricity generated at times when the direct solar light is not needed, inter alia when the area to be illuminated is empty. Thus, when there is no desire for daylight to be transmitted through the arrangement la, lb the visible part of the incident light may also be redirected towards the at least one energy converting element 5 a, 5b for energy conversion. This may inter alia be accomplished by bringing the at least one second dichroic filter 6a, 6b covering the at least one energy converting element 5 a, 5b down, as is schematically illustrated by the arrangement lc in Fig. 3.
  • Tilting of the at least one second dichroic filter 6a, 6b that reflects the visible part of the spectrum on top of the at least one first dichroic filter 7a, 7b that reflects the infrared part of the spectrum thus creates a geometry where all incident light is redirected towards the at least one energy converting element 5a, 5b.
  • Tilting of the at least one second dichroic filter 6a, 6b may be achieved by mechanically pivoting the at least one second dichroic filter 6a, 6b, as is illustrated in Fig. 3.
  • the movement of the at least one second dichroic filter 6a, 6b may be controlled by a controller 15 coupled to the at least one second dichroic filter 6a, 6b.
  • FIG. 5 An arrangement le with tilted at least one second dichroic filter 6a, 6b is illustrated in Fig. 5 where incident light 2 is received by the arrangement le at the first opening, where the visible part of the incident light is reflected by the at least one second dichroic filter 6a, 6b and where the infrared part of the incident light is reflected by the at least one first dichroic filter 7a, 7b.
  • the at least one second dichroic filter 6a, 6b may be arranged to receive light from the first opening, to reflect visible light and to transmit infrared light, wherein the at least one second dichroic filter 6a, 6b is in relation to the first opening positioned in front of the at least one first dichroic filter 7a, 7b such that visible light received by the at least one second dichroic filter 6a, 6b is reflected towards the at least one energy converting element 5a, 5b, thereby enabling both visible light and infrared light to be reflected towards the at least one energy converting element 5 a, 5b.
  • the result of the changed position of the at least one second dichroic filter 6a, 6b as illustrated in Fig. 5 is that all the light that is incident in the arrangement le is redirected to the solar cell and is thus used to generate electrical power.
  • This setting may thus be used when the user is not at home and/or there is no need or desire to have daylight in the building to be illuminated by means of the arrangement le. The daylight can then still be used effectively by converting it to electrical power via the at least one energy converting element 5 a, 5b.
  • the at least one first dichroic filter 7a, 7b (which reflects light having a wavelength above 800 nm) can be tilted up towards the at least one energy converting element 5 a, 5b and the at least one second dichroic filter 6a, 6b to allow all light to pass through the arrangement, without any light hitting the at least one energy converting element 5a, 5b.
  • the at least one first dichroic filter 7a, 7b may also be movable.
  • An arrangement If with tilted at least one first dichroic filter 7a, 7b is illustrated in Fig. 6 where incident light 2 is transmitted through the arrangement If from the first opening 12a to the second opening 12b.
  • the at least one first dichroic filter 7a, 7b may be arranged to be switched between a first operating state in which infrared light is reflected towards the at least one energy converting element 5 a 5b and a second operating state in which infrared light is transmitted towards the second opening.
  • the switch between the first operating state and the second operating state may be achieved my mechanically pivoting the at least one first dichroic filter 7a, 7b.
  • the switch may also be achieved by changing the internal state of the at least one first dichroic filter 7a, 7b.
  • the at least one first dichroic filter 7a, 7b may comprise components enabling the at least one first dichroic filter 7a, 7b to be internally switched upon receiving an activation or deactivation signal from the controller 15.
  • the controller 15 may thus be arranged to control the opacity at a given wavelength for the at least one first dichroic filter 7a, 7b.
  • the at least one second dichroic filter 6a, 6b may be internally switched.
  • Fig. 7 illustrates an arrangement lg having at least one first dichroic filter 7a, 7b which has been controlled by the controller 15 to transmit light at all wavelengths.
  • an anidolic integrated light system may comprise one or more arrangements la, lb, lc, Id, le, If, lg as disclosed above.
  • Fig. 8 illustrates one example of how an arrangement may lh be integrated with a building structure 13. Incident light 2 is received at the first opening 12a of the arrangement lh. Infrared light is received by the at least one energy converting element 5 a, 5b and visible light is transmitted out from the arrangement lh at the second opening 12b to illuminate a space inside the building. In the configuration illustrated in Fig. 8 the at least one energy converting element 5 a, 5b are obscured from view on the rooftops of buildings since the at least one energy converting element 5a, 5b is built into the arrangement lh which is placed inside the building.
  • dichroic filters include, but are not limited to so-called hot and cold mirrors.
  • Figs. 9a and 9b illustrate transmission versus wavelength for two dichroic filters.
  • Fig. 9a illustrates a filter response 14a for the above defined second dichroic filter; the transparency is close to 0 % for wavelengths below 800 nm and close to 100 % for wavelengths above 800 nm.
  • Fig. 9b illustrates a filter response 14b for the above defined first dichroic filter; the transparency is close to 100 % for wavelengths below 800 nm and close to 0 % for wavelengths above 800 nm.
  • the actual filter responses will depend on the actual dichroic filters used.
  • metal nanoantenna filters may be used.
  • the disclosed embodiments relate to a daylight harvesting system comprising a light tube.
  • the light tube may comprise at least one energy converting element, at least one first dichroic filter and at least one second dichroic filter.
  • the first dichroic filter may be arranged to transmit visible light and to reflect infrared light.
  • the second dichroic filter may be arranged to transmit infrared light and to reflect visible light.
  • the first dichroic filter may be located within the light tube so that incident infrared light is reflected towards the at least one energy converting element.
  • the at least one second dichroic filter may be located within the light tube so that in a first mode the at least one energy converting element is covered by the at least one second dichroic filter such that incident visible light is reflected away from the at least one energy converting element.
  • the at least one second dichroic filter may also be located within the light tube so that in a second mode incident visible light is reflected towards the at least one energy converting element.
  • the first dichroic filter and the second dichroic filter may cooperate to block daylight from reaching the outlet of the light tube, and to direct all daylight that enters the light tube towards the at least one energy converting element.
  • the at least one energy converting element is arranged to convert light into electrical energy.
  • the light tube may further comprises an energy storing element for storing the electrical energy, and for providing electrical power to one or more artificial light sources, such as LEDs, which may also be comprised in the light tube.

Abstract

There is provided an arrangement for light energy conversion which enables integration of one or more energy converting elements combined with one or more dichroic filters in a solar tube. A first set of dichroic filters may be mechanically aligned such that they direct infrared light towards the energy converting elements whilst the visible daylight is directed into an area to be illuminated. Alternatively all light may be directed towards the energy converting element or transmitted through the solar tube. The one or more energy converting elements may store the light into an energy storing element that in turn may be drained by artificial light under constant voltage. In this manner daylight is directly transmitted into the area to be illuminated when there is a demand.

Description

Arrangement for light energy conversion
FIELD OF THE INVENTION
The present invention relates in general to a daylight harvesting system, and in particular to an arrangement for light energy conversion in such a daylight harvesting system.
BACKGROUND OF THE INVENTION
There is a lot of daylight available during the day which currently is hardly used in windowless spaces. In professional buildings in areas like washrooms, halls and stairs often artificial light is constantly burning during working hours.
Additionally it is often desired by people to have natural light wherever possible. Also, having more natural light available inter alia in hospitals is known to be welcomed by personnel as well as patients.
Several options are known where daylight is put to more effective use such as the well known solar cell for energy conversion and storage, but also the use of anidolic ceilings, redirecting window blinds and light tubes.
Governmental rules are under way to ask for zero carbon buildings and as lighting is one of the big contributors to electrical power consumption in the building the reduction of this consumption required.
SUMMARY OF THE INVENTION
Photovoltaic elements receiving daylight have been used to generate electricity. This electricity may inter alia be used to power artificial light sources. However, in using photovoltaic elements to power artificial light sources most of the aspects of daylight that people prefer are lost. These aspects may include the broad spectrum, which yields light with a high color rendering index, the omnipresence of daylight, because 50 % of the daylight is diffuse light, the dynamics during the day in terms of color and direction, as well as the fact that daylight may be regarded as a highly collimated large area light source. All these aspects cannot be efficiently reproduced with artificial light sources. An undesired aspect of daylight however is that, due to the broad spectrum which extends into the far infrared part of the spectrum, also often undesired heat is allowed into the building through direct daylight systems. Also, the dynamic aspect of daylight can make it difficult to ensure a certain minimum level of light in the building at all times, thus requiring artificial light sources to replenish the daylight if needed, in an efficient way. It is an object of the present invention to overcome these problems, and to provide an improved lighting system that retains the desirable aspects of daylight and uses the non-visible part of the solar spectrum for light energy conversion.
The inventors of the disclosed embodiments have discovered that all the desirable aspects of daylight can be retained, whilst the infrared part of the collected daylight is received by an energy converting element thereby preventing heat exchange with the area to be illuminated. In this way also the, often undesired, the thermal radiation part of the solar spectrum (i.e. light from the infrared range of the spectrum) does not enter the building but is converted into energy that can be stored and used later, whilst the visible part of the solar spectrum is allowed into the building in a controlled way. Additionally, the generated energy can be used to power artificial light sources that can replenish the daylight, inter alia if the daylight levels are considered to be too low. It is an object of the present invention to provide such an arrangement.
Generally, the above objectives are achieved by an arrangement for light energy conversion according to the attached independent claim. According to a first aspect of the invention, this and other objects are achieved by an arrangement for light energy conversion, the arrangement having a first opening arranged to receive incident light entering the arrangement and a second opening arranged to emit output light from the arrangement, the arrangement comprising: at least one energy converting element arranged to convert light energy to electrical energy, and at least one first dichroic filter arranged to receive light from the first opening, to transmit visible light and to reflect infrared light, the at least one first dichroic filter being positioned such that received visible light is transmitted towards the second opening and such that received infrared light is reflected towards the at least one energy converting element.
Advantageously such an arrangement may provide an integrated solar light tube that transmits the visible part of the solar spectrum and captures the infrared part of the solar spectrum with the energy converting element. This has a twofold advantage. Firstly the heat associated with the received light is kept isolated from the area to be illuminated.
Secondly the energy (as contained in the infrared part of the received light) is converted efficiently to electricity. This electricity can be stored for later usage. According to embodiments the arrangement further comprises at least one second dichroic filter arranged to receive light from at least one of the first opening and the at least one first dichroic filter, wherein the at least one second dichroic filter is in relation to the first opening positioned in front of the at least one energy converting element such that visible light received by the at least one second dichroic filter is reflected towards the at least one first dichroic filter and infrared light received by the at least one second dichroic filter is transmitted towards the at least one energy converting element.
Since the at least one second dichroic filter reflects visible light towards the at least one first dichroic filter (which transmits visible light), advantageously this enables an increased amount of visible light to be outputted from the arrangement.
According to embodiments the arrangement further comprises at least one second dichroic filter arranged to receive light from the first opening, to reflect visible light and to transmit infrared light, wherein the at least one second dichroic filter is in relation to the first opening positioned in front of the at least one first dichroic filter such that visible light received by the at least one second dichroic filter is reflected towards the at least one energy converting element, thereby enabling both visible light and infrared light to be reflected towards the at least one energy converting element.
Advantageously such an arrangement enables a large portion of the received incident light at all wavelengths to be refiected towards and received by the energy converting element, thereby increasing the amount of energy to be converted.
According to embodiments at least one of the at least one first dichroic filter and/or the at least one second dichroic filter is mechanically movable. Advantageously this enables the arrangement to be switched between different energy conversion configurations. For example, in one state the energy converting element may receive both infrared and visible light, in another state the energy converting element may receive exclusively either infrared or visible light, and in yet another state the energy converting element may receive neither infrared nor visible light.
According to embodiments the arrangement further comprises an LED array, the LED array being powered with energy from the at least one energy converting element.
According to embodiments the arrangement further comprises a light sensor arranged to sense flux of incident light received by the arrangement, the light sensor being arranged such that the LED array is powered with energy from the energy storing element if and only if the sensed flux is below a predetermined threshold. Thus artificial light (such as light emitted by a LED array) may also fill in seamlessly. For example the artificial light may be emitted whenever the daylight is obstructed from reaching the energy converting element (such as when a cloud passes the sun). Artificial light may also be emitted at a fixed time of the day or whenever the daylight level (as defined by the sensed flux of incident light) is below requirements. Thus the arrangement may be also provided with LEDs to add illumination if the received daylight is not providing enough light to illuminate the area to be illuminated. For example, the LEDs may be powered in the evening using the electricity that was generated by the energy converting element by the received daylight.
According to a second aspect of the invention, the above object and other objects are achieved by a luminaire comprising an arrangement as disclosed above.
According to a third aspect of the invention, the above object and other objects are achieved by an anidolic integrated light system, comprising an arrangement as disclosed above.
It is noted that the invention relates to all possible combinations of features recited in the claims. Thus, all features and advantages of the first aspect likewise apply to the second and third aspects, respectively.
BRIEF DESCRIPTION OF THE DRAWINGS
The various aspects of the invention, including its particular features and advantages, will be readily understood from the following detailed description and the accompanying drawings, in which:
Figs. 1-8 illustrate arrangements for light energy conversion according to embodiments; and
Figs. 9a-9b illustrate filter responses for dichroic filters according to embodiments.
DETAILED DESCRIPTION OF THE EMBODIMENTS
The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and fully convey the scope of the invention to the skilled addressee. Like reference characters refer to like elements throughout.
Fig. 1 illustrates an arrangement la for light energy conversion according to an embodiment. The arrangement la may be (part of) a solar tube. The arrangement la may also be part of a luminaire. The arrangement la comprises at least one energy converting element 5a, 5b and at least one first dichroic filter 7a, 7b. The arrangement la has a first opening 12a and a second opening 12b. Incident light 2a, 2b {inter alia in the form of daylight from the sun) is received at the first opening 12a and output light is emitted from the arrangement 1 at the second opening 12b. The first opening 12a and the second opening 12b may thus be said to be positioned along a light axis 16. In general, the incident light 2a, 2b comprises visible light and infrared light of the light spectrum. In principal, visible light may be defined as light having a wavelength shorter than 800 nm. Infrared light may be defined as light having a wavelength longer than 800 nm. In Fig. 1 the infrared part of the incident light 2a, 2b is illustrated by solid lines. Similarly, visible light is illustrated by dotted, dash-dotted and dashed lines.
Upon entering the arrangement la at the first opening 12a the incident light is received by the at least one first dichroic filter, in Fig. 1 illustrated by two dichroic filters 7a, 7b. Thus the sunlight first hits a dichroic filter, that is positioned under an angle with respect to the axis of the incident light, in order to reflect the light with a wavelength longer than 800 nm (the infrared light) towards the at least one energy converting element, and to transmit the light with a wavelength shorter than 800 nm (the visible light). More particularly the at least one first dichroic filter 7a, 7b is arranged to receive light 2a, 2b from the first opening 12a and to transmit visible light (towards the second opening 12b) and to reflect infrared light (towards the at least one energy converting element 5a, 5b). The at least one first dichroic filter 7a, 7b is thus positioned such that received visible light is transmitted towards the second opening 12b and such that received infrared light is reflected towards the at least one energy converting element 5a, 5b. For example, the at least one first dichroic filter 7a, 7b may be arranged between the first opening 12a and the second opening 12b at an angle a larger than 0 degrees and smaller than 90 degrees, preferably 45 degrees, with respect to the light axis 16.
The infrared portion of the incident light is thus received by the at least one energy converting element 5a, 5b which is arranged to convert light energy to electrical energy. The at least energy converting element 5a, 5b may comprise one or more
photovoltaic cells. Alternatively to the one or more photovoltaic cells the at least energy converting element 5a, 5b may comprise a photo-luminescent concentrator connectable to a solar cell. The photo-luminescent concentrator then converts the light to longer wavelengths and guides it to a solar cell that is then mounted to the side of the photo-luminescent concentrator plate.
Although two first dichroic filters 7a, 7b are illustrated in Fig. 1 the arrangement la may, depending on the configuration of the arrangement la, have two or more first dichroic filters 7a, 7b. The disclosed embodiment are not limited to a particular number of first dichroic filters. Similarly, two energy converting elements 5a, 5b are illustrated in Fig. 1. Depending on the configuration of the arrangement la the arrangement la may have two or more energy converting elements 5a, 5b. The disclosed embodiment are not limited to a particular number of energy converting elements. According to embodiments the number of first dichroic filters 7a, 7b may be the same as the number of energy converting elements 5 a, 5b.
Fig. 2 illustrates an arrangement lb for light energy conversion according to an embodiment. The arrangement lb in Fig. 2 is similar to the arrangement la in Fig. 1 as disclosed above. The arrangement lb thus has a first opening 12a wherein incident light 2a, 2b is received and a second opening 12b from which output light is emitted. Incident light is received by at least one first dichroic filter 7a, 7b which is arranged to reflect infrared light towards at least one energy converting element 5 a, 5b and to transmit visible light towards the second opening 12b. The at least one energy converting element 5 a, 5b is thus arranged to convert the received infrared light into electrical energy.
The inner walls of the arrangement lb may be provided with a reflective surface being highly reflective for all wavelengths of light to allow light at all wavelengths to be efficiently reflected through the arrangement lb. The at least one energy converting element 5a, 5b may be arranged on the light reflective sidewalls.
The arrangement lb may further comprise a light collecting dome 3. The light collecting dome 3 is positioned at the first opening 12a. As the collecting dome 3 collects and redirects incident light 2a, 2b into the arrangement lb there is no need for weather protection covers to be integrated on top of the at least one energy converting element 5 a, 5b. Wear may thereby be minimized as the at least one energy converting element 5a, 5b is integrated inside the arrangement lb (which may be in a building structure, see Fig. 8). Particularly the collecting dome 3 may be arranged to collimate the entering incident light 2a, 2b towards the at least one first dichroic filter 7a, 7b. The arrangement lb may further comprise a diffuser 11. The diffuser 11 is positioned at the second opening 12b. The diffuser 11 is arranged to receive visible light from the at least one first dichroic filter 7a, 7b and to emit output light from the arrangement lb. The diffuser 11 may thereby enable the output light in a desired direction. The diffuser 11 is but one example of elements or devices which may be attached to the second opening 12b. As the skilled person understand additional filters, collimators, and the like may be equally provided at the second opening 12b in order to provide a specified light effect.
In addition, user requirements may dictate that the light output should be irrespective of the light conditions outside the arrangement lb (i.e. independent of the flux of the incident light 2a, 2b) and hence integrated artificial light sources, such as one or more LEDs 9a, 9b, 9c, 9d, 9e, 9f forming one or more LED arrays, are generally provided as well as a daylight dimming option. Thus, LEDs 9a, 9b, 9c, 9d, 9e, 9f may be comprised in the arrangement lb to compensate for reduced solar lighting (e.g. due to clouds, or at night). The power generated by the at least one energy converting element 5 a, 5b can be used to drive these LEDs. For powering artificial light (such as the one or more LEDs 9a, 9b, 9c, 9d, 9e, 9f) and many other appliances one may otherwise require AC/DC converters that generate energy losses. However, by connecting the at least one energy converting element 5a, 5b to an energy storing element 8, such as a battery, the artificial light can be powered without these losses. The arrangement lb may thus further comprise an energy storing element 8 arranged to store electrical energy received from the at least one energy converting element 5 a, 5b. The LED array may then be powered with energy from the at least one energy converting element 5 a 5b or with energy stored in the energy storing element 8. Thus no AC/DC conversion is needed in this case, which simplifies the drive system for the LEDs. Dimming may generally be provided by inserting a light reflecting or absorbing plate in the light collecting dome 3 that as a result would lead to spectral waste of the already collected solar radiation.
In order to enable the light output to be irrespective of the light conditions outside the arrangement lb the arrangement lb may further comprise a light sensor 4. The light sensor 4 may be arranged to sense flux of incident light received by the arrangement lb. The light sensor 4 may be operatively connected to a switch 10 positioned between the energy storing element 8 and the one or more LEDs 9a, 9b, 9c, 9d, 9e, 9f. The position of the switch may be determined by the sensed flux of incident light. For example, the light sensor 4 may be arranged such that the switch enables a current to be established between the energy storing element 8 and the one or more LEDs 9a, 9b, 9c, 9d, 9e, 9f if and only if the sensed flux of incident light is below a predetermined threshold, thereby enabling the one or more LEDs 9a, 9b, 9c, 9d, 9e, 9f to provide artificial light. Thus the light sensor 4 may thereby be arranged such that the LED array is powered with energy from the energy storing element 8 if and only if the sensed flux is below a predetermined threshold.
The arrangement lb may further comprise at least one second dichroic filter
6a, 6b. Depending on the configuration of the arrangement lb the arrangement lb may have two or more second dichroic filters 6a, 6b. The disclosed embodiment are not limited to a particular number of second dichroic filters. According to embodiments the number of second dichroic filters 6a, 6b may be the same as the number of energy converting elements 5a, 5b.
The at least one second dichroic filter 6a, 6b may be located over the surface area of the at least one energy converting element 5 a, 5b. In particular the at least one second dichroic filter may be arranged to receive light from at least one of the first opening 12a as well as from the at least one first dichroic filter 7a, 7b. The at least one second dichroic filter 6a, 6b may, in relation to the first opening 12a, be positioned in front of the at least one energy converting element 5 a, 5b such that visible light received by the at least one second dichroic filter 6a, 6b is reflected towards the at least one first dichroic filter 7a, 7b and infrared light received by the at least one second dichroic filter 6a, 6b is transmitted towards the at least one energy converting element 5a, 5b. The at least one second dichroic filter 6a, 6b may thus be arranged to reflect light having a wavelength shorter than 800 nm. Similarly the at least one second dichroic filter 6a, 6b may be arranged to transmit light having a wavelength longer than 800 nm. The at least one second dichroic filter 6a, 6b is thus arranged to reflect visible light and to transmits infrared light, such that it can be absorbed by the at least one energy converting element 5 a, 5b. This is done, because the sunlight can enter the dome 3 under all kinds of angles and the visible light should be guided into the building (i.e. be outputted from the second opening 12b of the arrangement lb, see also Fig. 8) and not be absorbed by the at least one energy converting element 5 a, 5b. As noted above the power generated in the at least one energy converting element 5 a, 5b can be stored in an energy storing element 8 for later use.
By repositioning the at least one second dichroic filter 6a, 6b the arrangement la, lb can be switched to collect all the incident light onto the at least one energy converting element 5 a, 5b. This increases the electricity generated at times when the direct solar light is not needed, inter alia when the area to be illuminated is empty. Thus, when there is no desire for daylight to be transmitted through the arrangement la, lb the visible part of the incident light may also be redirected towards the at least one energy converting element 5 a, 5b for energy conversion. This may inter alia be accomplished by bringing the at least one second dichroic filter 6a, 6b covering the at least one energy converting element 5 a, 5b down, as is schematically illustrated by the arrangement lc in Fig. 3. Tilting of the at least one second dichroic filter 6a, 6b that reflects the visible part of the spectrum on top of the at least one first dichroic filter 7a, 7b that reflects the infrared part of the spectrum thus creates a geometry where all incident light is redirected towards the at least one energy converting element 5a, 5b. Tilting of the at least one second dichroic filter 6a, 6b may be achieved by mechanically pivoting the at least one second dichroic filter 6a, 6b, as is illustrated in Fig. 3. The movement of the at least one second dichroic filter 6a, 6b may be controlled by a controller 15 coupled to the at least one second dichroic filter 6a, 6b.
An arrangement le with tilted at least one second dichroic filter 6a, 6b is illustrated in Fig. 5 where incident light 2 is received by the arrangement le at the first opening, where the visible part of the incident light is reflected by the at least one second dichroic filter 6a, 6b and where the infrared part of the incident light is reflected by the at least one first dichroic filter 7a, 7b. More particularly, the at least one second dichroic filter 6a, 6b may be arranged to receive light from the first opening, to reflect visible light and to transmit infrared light, wherein the at least one second dichroic filter 6a, 6b is in relation to the first opening positioned in front of the at least one first dichroic filter 7a, 7b such that visible light received by the at least one second dichroic filter 6a, 6b is reflected towards the at least one energy converting element 5a, 5b, thereby enabling both visible light and infrared light to be reflected towards the at least one energy converting element 5 a, 5b.
The result of the changed position of the at least one second dichroic filter 6a, 6b as illustrated in Fig. 5 is that all the light that is incident in the arrangement le is redirected to the solar cell and is thus used to generate electrical power. This setting may thus be used when the user is not at home and/or there is no need or desire to have daylight in the building to be illuminated by means of the arrangement le. The daylight can then still be used effectively by converting it to electrical power via the at least one energy converting element 5 a, 5b.
Furthermore, if there is a need of the consumer to bring in the solar heat (i.e. the infrared radiation) along with the visible light then, in a similar manner the at least one first dichroic filter 7a, 7b (which reflects light having a wavelength above 800 nm) can be tilted up towards the at least one energy converting element 5 a, 5b and the at least one second dichroic filter 6a, 6b to allow all light to pass through the arrangement, without any light hitting the at least one energy converting element 5a, 5b. Thus as is schematically illustrated in the arrangement Id of Fig. 4 the at least one first dichroic filter 7a, 7b may also be movable. An arrangement If with tilted at least one first dichroic filter 7a, 7b is illustrated in Fig. 6 where incident light 2 is transmitted through the arrangement If from the first opening 12a to the second opening 12b.
In general the at least one first dichroic filter 7a, 7b may be arranged to be switched between a first operating state in which infrared light is reflected towards the at least one energy converting element 5 a 5b and a second operating state in which infrared light is transmitted towards the second opening.
As illustrated above the switch between the first operating state and the second operating state may be achieved my mechanically pivoting the at least one first dichroic filter 7a, 7b. However, the switch may also be achieved by changing the internal state of the at least one first dichroic filter 7a, 7b. For example, the at least one first dichroic filter 7a, 7b may comprise components enabling the at least one first dichroic filter 7a, 7b to be internally switched upon receiving an activation or deactivation signal from the controller 15. The controller 15 may thus be arranged to control the opacity at a given wavelength for the at least one first dichroic filter 7a, 7b. Similarly the at least one second dichroic filter 6a, 6b may be internally switched. Thereby the need to mechanically pivot the at least one first dichroic filter 7a, 7b and/or the at least one second dichroic filter 6a, 6b may be eliminated. Fig. 7 illustrates an arrangement lg having at least one first dichroic filter 7a, 7b which has been controlled by the controller 15 to transmit light at all wavelengths.
The above disclosed arrangement la, lb, lc, Id, le, If, lg may be part of an anidolic integrated light system. In general, an anidolic integrated light system may comprise one or more arrangements la, lb, lc, Id, le, If, lg as disclosed above. Fig. 8 illustrates one example of how an arrangement may lh be integrated with a building structure 13. Incident light 2 is received at the first opening 12a of the arrangement lh. Infrared light is received by the at least one energy converting element 5 a, 5b and visible light is transmitted out from the arrangement lh at the second opening 12b to illuminate a space inside the building. In the configuration illustrated in Fig. 8 the at least one energy converting element 5 a, 5b are obscured from view on the rooftops of buildings since the at least one energy converting element 5a, 5b is built into the arrangement lh which is placed inside the building.
Examples of dichroic filters include, but are not limited to so-called hot and cold mirrors. Figs. 9a and 9b illustrate transmission versus wavelength for two dichroic filters. Fig. 9a illustrates a filter response 14a for the above defined second dichroic filter; the transparency is close to 0 % for wavelengths below 800 nm and close to 100 % for wavelengths above 800 nm. Fig. 9b illustrates a filter response 14b for the above defined first dichroic filter; the transparency is close to 100 % for wavelengths below 800 nm and close to 0 % for wavelengths above 800 nm. As the skilled person understands these are just illustrative filter responses. The actual filter responses will depend on the actual dichroic filters used. As an alternative to dichroic filters also metal nanoantenna filters may be used.
In summary the disclosed embodiments relate to a daylight harvesting system comprising a light tube. According to the embodiments, the light tube may comprise at least one energy converting element, at least one first dichroic filter and at least one second dichroic filter. The first dichroic filter may be arranged to transmit visible light and to reflect infrared light. The second dichroic filter may be arranged to transmit infrared light and to reflect visible light. The first dichroic filter may be located within the light tube so that incident infrared light is reflected towards the at least one energy converting element. The at least one second dichroic filter may be located within the light tube so that in a first mode the at least one energy converting element is covered by the at least one second dichroic filter such that incident visible light is reflected away from the at least one energy converting element. The at least one second dichroic filter may also be located within the light tube so that in a second mode incident visible light is reflected towards the at least one energy converting element. In the second mode, the first dichroic filter and the second dichroic filter may cooperate to block daylight from reaching the outlet of the light tube, and to direct all daylight that enters the light tube towards the at least one energy converting element. The at least one energy converting element is arranged to convert light into electrical energy. The light tube may further comprises an energy storing element for storing the electrical energy, and for providing electrical power to one or more artificial light sources, such as LEDs, which may also be comprised in the light tube.
The person skilled in the art realizes that the present invention by no means is limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims. For example, the disclosed arrangement can be applied to other daylight guiding systems, such as anidolic ceilings, light pipes, and the like.

Claims

CLAIMS:
1. An arrangement (la, lb, lc, Id, le, If, lg, lh) for light energy conversion, the arrangement having a first opening (12a) arranged to receive incident light (2, 2a, 2b) entering the arrangement and a second opening (12b) arranged to emit output light from the arrangement, the arrangement comprising:
at least one energy converting element (5a, 5b) arranged to convert light energy to electrical energy, and
at least one first dichroic filter (7a, 7b) arranged to receive light from the first opening, to transmit visible light and to reflect infrared light, the at least one first dichroic filter being positioned such that received visible light is transmitted towards the second opening and such that received infrared light is refiected towards the at least one energy converting element.
2. The arrangement according to claim 1, wherein the first opening and the second opening are positioned along a light axis (16) and wherein the at least one first dichroic filter is arranged between the first opening and the second opening at an angle (a) larger than 0 degrees and smaller than 90 degrees with respect to the light axis.
3. The arrangement according to claim 1 or 2, wherein the at least one dichroic filter is arranged to be switched between a first operating state in which infrared light is reflected towards the at least one energy converting element and a second operating state in which infrared light is transmitted towards the second opening.
4. The arrangement according to any one of claims 1-3, further comprising at least one second dichroic filter (6a, 6b) arranged to receive light from at least one of the first opening and the at least one first dichroic filter, wherein the at least one second dichroic filter is in relation to the first opening positioned in front of the at least one energy converting element such that visible light received by the at least one second dichroic filter is reflected towards the at least one first dichroic filter and infrared light received by the at least one second dichroic filter is transmitted towards the at least one energy converting element.
5. The arrangement according to any one of claims 1-4, further comprising at least one second dichroic filter (6a, 6b) arranged to receive light from the first opening, to reflect visible light and to transmit infrared light, wherein the at least one second dichroic filter is in relation to the first opening positioned in front of the at least one first dichroic filter such that visible light received by the at least one second dichroic filter is reflected towards the at least one energy converting element, thereby enabling both visible light and infrared light to be reflected towards the at least one energy converting element.
6. The arrangement according to claim 4 or 5, wherein the at least one first dichroic filter is arranged to reflect light having a wavelength longer than 800 nm, and wherein the at least one second dichroic filter is arranged to reflect light having a wavelength shorter than 800 nm.
7. The arrangement according to any one of claims 1-6, wherein the energy converting element comprises a photovoltaic cell or a photo-luminescent concentrator, the photo-luminescent concentrator being connectable to a solar cell.
8. The arrangement according to any one of claims 1-7, further comprising a light collecting dome (3) positioned at the first opening, the collecting dome being arranged to collimate the entering incident light towards the at least one first dichroic filter.
9. The arrangement according to any one of claims 1-8, further comprising a diffuser (11) positioned at the second opening, the diffuser and arranged to receive visible light from the at least one first dichroic filter and to emit output light from the arrangement.
10. The arrangement according to any one of claims 1-9, further comprising an energy storing element (8), the energy storing element being arranged to store electrical energy received from the energy converting element.
11. The arrangement according to any one of claims 1-10, further comprising an LED array (9a, 9b, 9c, 9d, 9e, 9f), the LED array being powered with energy from the at least one energy converting element.
12. The arrangement according to claim 11 when dependent on claim 10, further comprising a light sensor (4) arranged to sense flux of incident light received by the arrangement, the light sensor being arranged such that the LED array is powered with energy from the energy storing element if and only if the sensed flux is below a predetermined threshold.
13. The arrangement according to any one of claims 1-12, further comprising light reflective sidewalls, wherein the at least one energy converting element is arranged on said light reflective sidewalls.
14. A luminaire comprising an arrangement according to any one of claims 1-13.
15. An anidolic integrated light system comprising an arrangement according to any one of claims 1-13.
PCT/IB2011/053751 2010-09-06 2011-08-26 Arrangement for light energy conversion WO2012032431A2 (en)

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