WO2015031135A1 - Collecteur d'énergie solaire à spectre divisé - Google Patents

Collecteur d'énergie solaire à spectre divisé Download PDF

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Publication number
WO2015031135A1
WO2015031135A1 PCT/US2014/051939 US2014051939W WO2015031135A1 WO 2015031135 A1 WO2015031135 A1 WO 2015031135A1 US 2014051939 W US2014051939 W US 2014051939W WO 2015031135 A1 WO2015031135 A1 WO 2015031135A1
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WO
WIPO (PCT)
Prior art keywords
receiver
heat
visible
solar
infrared
Prior art date
Application number
PCT/US2014/051939
Other languages
English (en)
Inventor
Gilad Almogy
Ratson Morad
Itai Suez
Original Assignee
Cogenra Solar, Inc.
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 Cogenra Solar, Inc. filed Critical Cogenra Solar, Inc.
Publication of WO2015031135A1 publication Critical patent/WO2015031135A1/fr

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Classifications

    • 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
    • F24—HEATING; RANGES; VENTILATING
    • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S23/00—Arrangements for concentrating solar-rays for solar heat collectors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S23/00—Arrangements for concentrating solar-rays for solar heat collectors
    • F24S23/70—Arrangements for concentrating solar-rays for solar heat collectors with reflectors
    • F24S23/74—Arrangements for concentrating solar-rays for solar heat collectors with reflectors with trough-shaped or cylindro-parabolic reflective surfaces
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S50/00—Arrangements for controlling solar heat collectors
    • F24S50/20—Arrangements for controlling solar heat collectors for tracking
    • 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
    • H01L31/0547—Optical elements directly associated or integrated with the PV cell, e.g. light-reflecting means or light-concentrating means comprising light concentrating means of the reflecting type, e.g. parabolic mirrors, concentrators using total internal reflection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02S—GENERATION OF ELECTRIC POWER BY CONVERSION OF INFRARED RADIATION, VISIBLE LIGHT OR ULTRAVIOLET LIGHT, e.g. USING PHOTOVOLTAIC [PV] MODULES
    • H02S40/00—Components or accessories in combination with PV modules, not provided for in groups H02S10/00 - H02S30/00
    • H02S40/40—Thermal components
    • H02S40/44—Means to utilise heat energy, e.g. hybrid systems producing warm water and electricity at the same time
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S20/00—Solar heat collectors specially adapted for particular uses or environments
    • F24S20/20—Solar heat collectors for receiving concentrated solar energy, e.g. receivers for solar power plants
    • 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
    • Y02E10/40—Solar thermal energy, e.g. solar towers
    • Y02E10/44—Heat exchange systems
    • 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
    • Y02E10/40—Solar thermal energy, e.g. solar towers
    • Y02E10/47—Mountings or tracking
    • 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
    • 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
    • Y02E10/60—Thermal-PV hybrids

Definitions

  • Described herein are systems, methods and apparatus relating generally to the collection of solar energy to provide electrical energy, thermal energy, or electrical energy and thermal energy.
  • Solar energy supply is sufficient in many geographical regions to satisfy energy demands, in part, by provision of electric power and useful heat.
  • Solar energy systems may be used to replace or augment traditional energy sources powered by fossil fuel. Improved solar energy systems are needed to satisfy increasing worldwide energy demands. Solar energy systems with improved efficiency are needed.
  • the systems, methods and apparatus utilize a split solar spectrum, in which solar radiation is split into at least a visible band and an infrared band.
  • the systems, methods and apparatus utilize at least two receivers: a first receiver tuned or optimized for generating useful electricity and/or heat from the visible band; and a second receiver tuned or optimized for generating useful heat and/or electricity from the infrared band.
  • a concentrating solar energy system comprising a trough reflector for focusing incident solar radiation to a linear focus.
  • the system comprises an optical filter capable of splitting the solar spectrum into at least a visible beam having a predetermined visible wavelength range and an infrared beam having a
  • the system comprises a first receiver capable of generating electricity and optionally heat from the visible beam, and a second receiver capable of generating heat and/or electricity from the infrared beam.
  • the reflector directs incident solar radiation to the optical filter that splits the solar radiation into at least the visible beam and the infrared beam, the visible beam is directed to the first receiver to generate electricity (and optionally heat), and the infrared beam is directed to the second receiver to generate heat and/or electricity.
  • the optical filter may direct the visible beam to the first receiver and the infrared beam to the second receiver.
  • one or more optical elements may be employed to direct the visible beam from the optical filter to the first receiver, and/or one or more optical elements may be employed to direct the infrared beam to the second receiver.
  • the first receiver may comprise photovoltaic solar cells for generating electricity from the visible beam and/or a solar thermal collector for collecting heat from the visible beam.
  • the first receiver comprises photovoltaic solar cells for generating electricity from the visible beam.
  • the first receiver is a photovoltaic receiver, and in other cases the first receiver is or comprises a photovoltaic -thermal solar receiver comprising photovoltaic solar cells for generating electricity from the visible beam and a solar thermal collector for collecting heat from the visible beam.
  • the second receiver may comprise photovoltaic solar cells for generating electricity from the infrared beam and/or a solar thermal collector for collecting heat from the infrared beam.
  • the second receiver is a solar thermal collector
  • the second receiver is a photovoltaic receiver
  • the second receiver is or comprises a photovoltaic -thermal solar receiver comprising photovoltaic solar cells for generating electricity from the infrared beam and a solar thermal collector for collecting heat from the infrared beam.
  • the first and second receivers in a system may be configured according to any one of the following variations: a) the first receiver comprises photovoltaic solar cells capable of generating electricity from the visible beam but does not collect heat, and the second receiver comprises photovoltaic solar cells capable of generating electricity from the infrared beam but does not collect heat; b) the first receiver comprises photovoltaic solar cells capable of generating electricity from the visible beam but does not collect heat, and the second receiver comprises a solar thermal collector capable of generating heat from the infrared beam but does not include photovoltaic solar cells; c) the first receiver comprises photovoltaic solar cells capable of generating electricity from the visible beam but does not collect heat, and the second receiver comprises a photovoltaic -thermal solar receiver capable of generating electricity and collecting heat from the infrared beam; d) the first receiver comprises a photovoltaic -thermal solar receiver capable of generating electricity and collecting heat from the visible beam, and the second receiver comprises photovoltaic solar cells capable of
  • a system may be configured for storing heat generated by the first receiver from the visible beam, if the first receiver is configured for collecting heat, and/or storing heat generated by the second receiver from the infrared beam, if the second receiver is configured for collecting heat.
  • a system may be capable of converting the stored heat into electricity.
  • heat collected by one or both of the first and second receivers may be stored, and subsequently converted into electricity upon demand, for example, at a time of high power demand, at a time of low sunlight or darkness, or at a time at which electricity has high commercial value.
  • a system's capability to store heat for later use, e.g., to generate electricity on demand may increase the commercial value of heat collected by the first and/or second receiver.
  • the solar spectrum may be split in such a manner as to increase the total commercial value of energy output (heat energy and electrical energy) from the first and second receivers.
  • a wavelength or a wavelength range at which the optical filter splits the solar spectrum into at least the visible band and the infrared band may be selected based on any one of or any combination of two or more of the following factors: a) a wavelength dependence of an external quantum efficiency of solar cells in the first receiver; b) a wavelength dependence of an external quantum efficiency of solar cells in the second receiver, if the second receiver comprises photovoltaic solar cells; c) the commercial value of heat collected by the first receiver, if the first receiver is configured for collecting heat; and d) the commercial value of heat collected by the second receiver, if the second receiver is configured for collecting heat.
  • one or more performance characteristics of the optical filter, the first receiver, and/or the second receiver is selected to increase, optimize or maximize the total commercial value of the electricity and/or heat generated by the first and second receivers over a predetermined time period. For example, if ⁇ is a characteristic wavelength of the optical filter that represents a boundary wavelength between the visible band and the infrared band, then ⁇ may be selected to be red-shifted toward the infrared to increase energy output (electrical and/or heat energy) from the second receiver, or ⁇ may be selected to be blue-shifted toward the visible to increase energy output (electrical energy and optionally heat energy) from the first receiver, to increase the total commercial value of electricity and heat that is generated by the first and second receivers combined, integrated over a desired time period (e.g., a day, a week, a month, a season, or a year). In some cases, the commercial value of heat generated by the first and/or second receivers is increased by an ability to store the heat for later use (e.
  • the first receiver upon which the visible beam is concentrated typically comprises solar cells having increased or optimized efficiency for generating usable electricity from the predetermined visible wavelength range of the visible beam.
  • the first receiver is a photovoltaic receiver
  • the first receiver is a photovoltaic- thermal solar receiver that comprises photovoltaic solar cells capable of generating usable electricity from the visible band and a solar thermal collector capable of generating usable heat from the visible band.
  • the first receiver comprises a solar thermal collector, any suitable type of solar thermal collector may be used.
  • the first receiver may comprise one or more fluid channels (e.g., one or more solar absorber pipes) carrying a working fluid to collect heat.
  • the second receiver upon which the infrared beam is concentrated may comprise a photovoltaic receiver and/or a solar thermal collector.
  • the second receiver comprises a photovoltaic -thermal solar receiver that comprises photovoltaic solar cells capable of generating usable electricity from the infrared band and a solar thermal collector capable of generating usable heat from the infrared band. If the second receiver comprises photovoltaic solar cells, the solar cells may have increased or optimized efficiency for generating usable electricity from the predetermined infrared wavelength range of the infrared beam. If the second receiver is or comprises a solar thermal collector, any type of solar thermal collector may be used.
  • a solar receiver may comprise one or more fluid channels (for example, one or more solar absorber pipes) carrying a working fluid to collect heat.
  • a solar selective coating may be applied to one or more components (e.g., solar absorber pipes) of a solar thermal collector to increase heat collection.
  • a solar selective coating applied to a solar absorber in the first receiver may be selected or tailored to collect heat from the visible beam
  • a solar selective coating applied to a solar absorber in the second receiver may be selected or tailored to collect heat from the infrared beam.
  • the first receiver and/or the second receiver comprises a thermo-electric device.
  • any suitable type of optical filter may be used to split the solar radiation into at least a visible band and an infrared band so that the resulting visible beam and infrared beam may be directed separately to the first and second receivers.
  • the optical filter may comprise a reflector or dichroic beam splitter (e.g., beam splitting cube) that selectively transmits visible light and reflects infrared radiation, or a reflector or dichroic beam splitter that selectively transmits infrared and reflects visible.
  • a reflector or dichroic beam splitter e.g., beam splitting cube
  • Some suitable optical filters that may be used are dichroic filters or dichroic thin film coatings that selectively transmit
  • an optical filter may be a single optical element or a group of optical elements that function together to split the solar spectrum as desired.
  • an optical filter may be or may comprise a prism or a diffraction grating that separates visible light from infrared radiation.
  • the optical filter may be or may comprise any type of chromatic dispersion element capable of spatially separating light of visible wavelengths from infrared wavelengths.
  • the optical filter transmits the visible portion of the solar radiation to the first receiver and reflects the infrared portion to the second receiver. In other variations, the optical filter transmits the infrared portion of the solar radiation to the second receiver and reflects the visible portion to the first receiver.
  • the optical filter may be positioned in any suitable location relative to the trough reflector and relative to the first and second receivers. In some cases, the optical filter is positioned adjacent the receiving surface of the first receiver. In some cases, the optical filter is positioned adjacent the receiving surface of the second receiver. In some cases, the optical filter comprises a thin film dichroic coating applied to a receiving surface of the first receiver, where the thin film selectively transmits the visible portion of the solar spectrum to the first receiver and selectively reflects the infrared portion of the spectrum to be separately directed to the second receiver.
  • the optical filter comprises a thin film dichroic coating applied to a receiving surface of the second receiver, where the thin film dichroic coating selectively transmits the infrared portion of the solar spectrum to the second receiver and selectively reflects the visible portion of the solar spectrum to be separately directed to the first receiver.
  • the system utilizes a focusing reflector to concentrate the solar radiation. Because the optical filter splits the solar spectrum to provide spatially displaced visible and infrared beams, the concentration of the visible light at the first receiver and the concentration of the infrared radiation at the second receiver may be independently varied. Radiation
  • concentration at the first receiver may be adjusted by placement of the first receiver relative to the focus of the visible beam
  • radiation concentration at the second receiver may be adjusted by placement of the second receiver relative to the focus of the infrared beam.
  • the visible beam is focused on the first receiver, so that the visible radiation is most concentrated at the first receiver.
  • the infrared beam is focused on the second receiver so that infrared radiation is most concentrated at the second receiver.
  • the visible beam is focused on the first receiver and the infrared beam is focused on the second receiver.
  • the visible beam is not focused on the first receiver, and instead, the first receiver is positioned to receive the visible beam at a location prior to or after the focus of the visible beam.
  • the infrared beam is not focused on the second receiver, and instead the second receiver is positioned to receive the infrared beam at a location other than its focus.
  • the visible beam is not focused on the first receiver and the infrared beam is focused on the second receiver.
  • the visible beam is focused on the first receiver and the infrared beam is not focused on the second receiver.
  • the visible beam is not focused on the first receiver and the infrared beam is not focused on the second receiver.
  • the system may comprise one or more additional optical elements for redirecting, filtering, diffusing and/or focusing the visible or infrared beams.
  • the first receiver may comprise a photovoltaic- thermal solar receiver and the second receiver may comprise a solar thermal collector or a photovoltaic -thermal solar receiver.
  • the first receiver comprises one or more fluid channels for carrying a working fluid.
  • the system may be configured so that during operation, the first receiver receives the visible beam to generate electricity and to preheat a working fluid carried in the one or more fluid channels of the first receiver, and the heat content of the preheated working fluid is boosted in the second receiver by heat collected from the infrared beam.
  • the second receiver is a photovoltaic-thermal solar receiver
  • the infrared beam may be used to generate electricity as well as to boost the heat of the preheated working fluid.
  • a method comprises reflecting incident solar radiation with a trough reflector, splitting the reflected solar radiation into at least a visible beam having a predetermined visible wavelength range and an infrared beam having a predetermined infrared wavelength range, receiving the visible beam with a first receiver to generate electricity and optionally heat, and receiving the infrared beam with a second receiver to generate heat and/or electricity.
  • the methods may allow increased collection efficiency and/or increase the total quantity of energy (electrical energy and heat energy) collected by the first and second receivers. For example, because infrared radiation is not incident on a photovoltaic receiver tailored for the visible, the method may allow a photovoltaic receiver to operate at cooler temperatures, thereby increasing efficiency. Further, reduction of extraneous radiation at the receiver may reduce damage, especially over extended periods.
  • a method may comprise splitting the solar spectrum in such a manner as to increase a total commercial value of energy output (heat energy and electrical energy) from the first and second receivers.
  • the first receiver employed by a method may comprise photovoltaic solar cells for generating electricity from the visible beam and/or a solar thermal collector for collecting heat from the visible beam.
  • the first receiver comprises photovoltaic solar cells capable of generating electricity from the visible beam.
  • the first receiver is a photovoltaic receiver, and in other cases the first receiver is a photovoltaic -thermal solar receiver comprising solar cells capable of generating electricity from the visible beam and a solar thermal collector capable of generating heat from the visible beam.
  • a solar thermal collector if present in the first receiver, may be any suitable solar thermal collector.
  • a first receiver may comprise one or more solar absorber pipes that optionally may be coated with a solar selective coating for absorbing the visible beam to produce heat.
  • the second receiver employed by the methods may comprise any suitable receiver capable of generating heat and/or electricity from the infrared beam.
  • the second receiver comprises photovoltaic solar cells capable of generating electricity from the infrared beam, a solar thermal collector capable of generating heat from the infrared beam, or a photovoltaic -thermal solar receiver capable of generating electricity and heat from the infrared beam.
  • a solar thermal collector, if present in the second receiver may be any suitable solar thermal collector.
  • a second receiver may comprise one or more solar absorber pipes that optionally may be coated with a solar selective coating for absorbing the infrared beam to produce heat.
  • the first receiver and/or the second receiver may comprise a thermo-electric device.
  • a method may comprise any of the following variations: a) generating electricity but not collecting heat with the first receiver and generating electricity but not collecting heat with the second receiver; b) generating electricity but not collecting heat with the first receiver and collecting heat but not generating electricity with the second receiver; c) generating electricity but not collecting heat with the first receiver and collecting heat and generating electricity with the second receiver; d) generating electricity and collecting heat with the first receiver and generating electricity but not collecting heat with the second receiver; e) generating electricity and collecting heat with the first receiver and collecting heat but not generating electricity with the second receiver; and f) generating electricity and collecting heat with the first receiver and generating electricity and collecting heat with the second receiver.
  • a method comprises collecting heat with the first receiver using the visible beam and/or collecting heat with the second receiver using the infrared beam, and storing the generated heat.
  • a method may comprise converting the stored heat into electricity upon demand, e.g., for use during high power demand periods, for use during darkness or low sunlight periods, or to produce electricity at a time when a market value for electricity is increased.
  • a method may comprise using a photovoltaic -thermal solar receiver as the first receiver and a solar thermal or photovoltaic -thermal solar receiver as the second receiver.
  • the first receiver receives visible light to generate electricity and to preheat a working fluid carried in one or more fluid channels of the first receiver, and a heat content of the preheated working fluid is boosted using heat generated by the second receiver from the infrared beam.
  • the second receiver is a photovoltaic -thermal solar receiver
  • a method may comprise using the infrared beam to generate electricity as well as to boost the heat of the preheated working fluid.
  • the methods may comprise splitting the solar radiation into at least the visible beam and infrared beam based on any one of or any combination of two or more of the following factors: a) a wavelength dependence of an external quantum efficiency of solar cells in the first receiver; b) a wavelength dependence of an external quantum efficiency of solar cells in the second receiver, if the second receiver comprises photovoltaic solar cells; c) the commercial value of heat collected by the first receiver, if the first receiver is configured for collecting heat; and d) the commercial value of heat collected by the second receiver, if the second receiver is configured for collecting heat.
  • the commercial value of heat collected by the first and/or second receiver may be increased by a capability to store the heat for later use, e.g., to generate electricity at a time when a commercial value of electricity is increased.
  • a method may comprise splitting the solar radiation into at least the visible beam and infrared beam to increase or optimize a total commercial value of electricity and/or heat generated by the first and second receivers over a predetermined time period (e.g., a day, a week, a month, a season, or a year).
  • a predetermined time period e.g., a day, a week, a month, a season, or a year.
  • one or more performance characteristics of the optical filter, the first receiver, and/or the second receiver is selected to increase, optimize or maximize the total commercial value of electricity and heat generated by the first and second receivers.
  • ⁇ is a characteristic wavelength of the optical filter that represents a boundary wavelength between the visible wavelength range and the infrared wavelength range
  • ⁇ may be selected to be red- shifted toward the infrared to increase energy output (electrical and/or heat energy) from the second receiver or ⁇ may be selected to be blue-shifted toward the visible to increase energy output (electrical and optionally heat energy) from the first receiver to increase the total commercial value of electrical and heat energy that is generated by the first and second receivers combined, integrated over a desired time period (e.g., a day, a week, a month, a season, or a year).
  • the commercial value of heat generated by the first and/or second receivers may be increased by an ability to store the heat for later use (e.g., for conversion to electricity at a time when a commercial value of electricity is high).
  • any suitable means or apparatus may be used to split the solar radiation into the visible beam and infrared beam.
  • a reflector or beam splitting cube that selectively transmits visible radiation and reflects infrared radiation, or a reflector that selectively transmits infrared radiation and reflects visible radiation may be used.
  • a dichroic beam splitter e.g., beam splitting cube
  • a prism or optical grating may be used as the optical filter.
  • a thin film dichroic coating is applied to a receiving surface of the first receiver that selectively transmits visible light to the first receiver and reflects infrared radiation that is directed to the second receiver.
  • a thin film dichroic coating is applied to a receiving surface of the second receiver that transmits infrared radiation to the second receiver and reflects visible light that is directed to the first receiver.
  • the methods disclosed herein provide for independently adjusting the concentration of the visible and infrared beams at the first receiver and at the second receiver, respectively.
  • the methods comprise receiving the visible beam at its focus with first receiver.
  • the methods comprise receiving the infrared beam at its focus with the second receiver.
  • the visible beam is not be focused on the first receiver to reduce intensity (e.g., to reduce operating temperature and/or damage to solar cells).
  • the infrared beam is not focused on the second receiver.
  • Some methods comprise receiving the visible beam at its focus with the first receiver and receiving the infrared beam at its focus with the second receiver.
  • Some methods comprise receiving the visible beam at a position other than its focus with the first receiver and receiving the infrared beam at its focus with the second receiver. Some methods comprise receiving the visible beam at its focus with the first receiver and receiving the infrared beam at a position other than its focus with the second receiver. Some methods comprise receiving the visible beam at a position other than its focus with the first receiver and receiving the infrared beam at a position other than its focus with the second receiver.
  • Figure 1 shows a cross-sectional view (section through trough reflector) of a non- limiting example of a solar energy collection system utilizing a split solar spectrum.
  • the system comprises a trough reflector, an optical filter for splitting the solar spectrum into a visible band and an infrared band, a first receiver capable of generating useful electricity from the visible band, and a second receiver capable of generating heat from the infrared band.
  • the detail view A shows an expanded view of the optical filter that splits solar radiation into a visible beam and an infrared beam, the first receiver and the second receiver.
  • Figure 2 shows a cross-sectional view (section through trough reflector) of another non-limiting example of a solar energy collection system utilizing a split solar spectrum.
  • the system comprises a trough reflector, an optical filter for splitting the solar spectrum into a visible band and an infrared band, a first receiver capable of generating useful electricity from the visible band, and a second receiver capable of generating useful electricity from the infrared band.
  • the detail view A shows an expanded view of the optical filter that splits solar radiation into a visible beam and an infrared beam, the first receiver and the second receiver.
  • Figure 3 shows a cross-sectional view (section through trough reflector) of yet another example of a solar energy collection system utilizing a split solar spectrum.
  • the system comprises a trough reflector, an optical filter for splitting the solar spectrum into a visible band and an infrared band, a first receiver capable of generating useful electricity from the visible band, and a second receiver capable of generating heat from the infrared band.
  • the first receiver is not located at the focus of the visible beam (e.g., to reduce operating temperature of solar cells and/or to reduce damage), and the second receiver is located at the focus of the infrared beam so that the infrared radiation is most concentrated at the solar thermal receiver.
  • Detail view A shows an expanded view of the optical filter that splits solar radiation into a visible beam and an infrared beam, the first receiver and the second receiver.
  • Figure 4 shows a cross-sectional view (section through trough reflector) of another non-limiting example of a solar energy collection system utilizing a split solar spectrum.
  • the system comprises a trough reflector, an optical filter for splitting the solar spectrum into a visible band and an infrared band, a first receiver for generating useful electricity from the visible band, and a second receiver for generating heat from the infrared band.
  • the optical filter comprises a thin film dichroic coating applied to a receiving surface of the first receiver, which is not located at the focus of the visible beam to allow for reduced intensity at the first receiver (e.g., to reduce operating temperature of solar cells and/or to reduce damage).
  • the second receiver is located at the focus of the infrared beam to receive infrared radiation at highest intensity.
  • Detail view A shows an expanded view of the optical filter that splits solar radiation into a visible beam and an infrared beam, the first receiver and the second receiver.
  • the concentrating solar energy collecting systems and methods described herein utilize at least one trough reflector to reflect and concentrate incident sunlight to a linear focus.
  • the sunlight reflected by the trough reflector is incident upon an optical filter (e.g., a dichroic reflector, dichroic beam splitting prism, optical grating, or the like) which splits the solar radiation into multiple wavelength bands.
  • the systems and methods utilize multiple receivers, with each receiver selected for and tuned or optimized for receiving radiation from one or more of the distinct wavelength bands and converting that radiation into useful electricity or heat.
  • the receivers may be independently selected and tuned or optimized for generating usable electricity and/or heat from their respective wavelength bands. For example, by splitting the spectrum into ultraviolet, visible and infrared bands, only the visible band may be directed to a visible photovoltaic receiver or a photovoltaic -thermal receiver selected to operate specifically for that wavelength range. By directing the infrared and ultraviolet wavelengths away from the receiver configured for receiving visible radiation, the receiver receives less extraneous radiation, which may reduce its operating temperature, thereby increasing efficiency, and reduce damage, especially after long term use. Further, each of the multiple receivers may be independently positioned to adjust the concentration of incident radiation. For example, one receiver may be placed at a focus of a beam having its corresponding wavelength band to receive highly concentrated radiation, and another receiver in the same system may be placed to receive a defocused beam of its corresponding wavelength band to receive less concentrated radiation.
  • one or more performance characteristics of the multiple receivers and/or of the optical filter that splits the solar radiation into multiple band may be tailored or optimized to increase energy output and/or a total quantity or total commercial value of electrical and thermal energy that is generated by the multiple receivers from the multiple wavelength bands.
  • the optical filter may be selected to split the solar radiation into a wavelength band having increased wavelength overlap with a wavelength dependent external quantum efficiency of the solar cells.
  • a solar selective coating may be selected or tuned for the wavelength band directed to that receiver.
  • heat optionally may be stored for later use to increase its commercial value. For example, stored heat may be converted electricity at a time when a commercial value of electricity is high.
  • concentrating solar energy collection systems comprising a trough reflector for focusing incident solar radiation to a linear focus.
  • the systems comprise an optical filter capable of splitting the solar spectrum into at least a visible band having a predetermined visible wavelength range and an infrared band having a predetermined infrared wavelength range.
  • the systems comprise a first receiver configured for generating electricity and/or heat from the visible band, and a second receiver configured for generating electricity and/or heat from the infrared band.
  • the optical filter may be capable of splitting the solar spectrum into more than two wavelength bands.
  • an optical filter may be used to split the solar spectrum into three bands: an ultraviolet band, a visible band, and an infrared band. The ultraviolet band may be reflected or transmitted along with the infrared band, for example.
  • the methods comprise reflecting and concentrating incident solar radiation with a trough reflector, splitting the reflected solar radiation into at least a visible beam having a predetermined visible wavelength range and an infrared beam having a predetermined infrared wavelength range, receiving the visible beam with a first receiver to generate usable electricity and optionally heat, and receiving the infrared beam with a second receiver to generate usable heat and/or electricity.
  • Some methods comprise splitting the solar radiation into more than two bands, e.g., a visible band having a predetermined visible wavelength range, an infrared band having a predetermined infrared wavelength range, and an ultraviolet band having a predetermined ultraviolet wavelength range.
  • the ultraviolet band may be reflected or transmitted along with the infrared band, for example.
  • the solar spectrum is split into at least a visible band having a predetermined visible wavelength range and an infrared band having a predetermined infrared wavelength range, and the systems and methods utilize at least two receivers.
  • the first receiver is any type of receiver (e.g., photovoltaic, solar thermal, photovoltaic -thermal, or thermoelectric) that is capable of or optimized for generating usable electricity and/or heat from the visible band
  • the second receiver is any type of receiver (e.g., solar thermal, photovoltaic, photovoltaic -thermal, or thermoelectric) that is capable of or optimized for generating heat and/or electricity from the infrared band.
  • the first receiver is or comprises a photovoltaic receiver comprising solar cells capable of generating electricity from the visible band, or a photovoltaic -thermal solar receiver comprising a photovoltaic receiver capable of generating electricity from the visible band and a solar thermal collector capable of generating heat from the visible band.
  • the second receiver is one of the following: a photovoltaic receiver comprising solar cells capable of generating electricity from the infrared band; a solar thermal collector capable of generating heat from the infrared band; or a photovoltaic-thermal solar receiver comprising solar cells capable of generating electricity from the infrared band and a solar thermal collector capable of generating heat from the infrared band.
  • the solar spectrum may be split into more than two wavelengths bands, and these systems may correspondingly comprise more than two receivers, where each receiver is selected for efficient generation of usable electricity and/or heat from its respective wavelength band of radiation.
  • one or more wavelength bands created during splitting of the solar spectrum may not be directed to a receiver, and instead may be discarded or put to an alternate use. For example, certain very short UV wavelengths that are not efficiently converted to electricity by solar cells and tend to damage solar cells may be split and directed away from a photovoltaic receiver.
  • the trough reflector directs incident solar radiation to an optical filter that splits the solar radiation into at least a visible beam having a predetermined visible wavelength range and an infrared beam having a
  • the trough reflector may direct incident solar radiation to one or more additional reflectors that, in turn, directs the solar radiation to the optical filter.
  • the visible beam is directed to the first receiver to generate electricity and optionally heat
  • the infrared beam is directed to the second receiver to generate heat and/or electricity.
  • the optical filter e.g., a dichroic reflector, a dichroic beam splitter, an optical prism, an optical grating, or the like
  • the optical filter that splits the solar radiation into the visible and infrared beam also directs the visible beam to the first receiver and directs the infrared beam to the second receiver.
  • one or more additional optical elements may be employed to direct (and optionally focus) the visible beam from the optical filter to the first receiver, and/or one or more additional optical elements (e.g., reflectors, prisms, lenses, and the like) may be employed to direct (and optionally focus) the infrared beam to the second receiver.
  • additional optical elements e.g., reflectors, prisms, lenses, and the like
  • the first and second receivers employed by the systems and methods described herein may be configured according to any one of the following variations: a) the first receiver comprises photovoltaic solar cells capable of generating electricity from the visible beam, and the second receiver comprises photovoltaic solar cells capable of generating electricity from the infrared beam; b) the first receiver comprises photovoltaic solar cells capable of generating electricity from the visible beam, and the second receiver comprises a solar thermal collector capable of generating heat from the infrared beam; c) the first receiver comprises photovoltaic solar cells capable of generating electricity from the visible beam, and the second receiver comprises a photovoltaic -thermal solar receiver capable of generating electricity and heat from the infrared beam; d) the first receiver comprises a photovoltaic -thermal solar receiver capable of generating electricity and heat from the visible beam, and the second receiver comprises photovoltaic solar cells capable of generating electricity from the infrared beam; e) the first receiver comprises a photovoltaic -thermal
  • heat generated by the first receiver from the visible beam (if the first receiver is configured for collecting heat) and/or heat generated by the second receiver from the infrared beam (if the second receiver is configured for collecting heat) may be stored for later use.
  • the stored heat is converted to electricity upon demand.
  • heat collected by one or both of the first and second receivers may be stored (e.g., in one or more reservoirs), and the stored heat may be subsequently converted to electricity upon demand, e.g., at a time of high power demand, at a time of low sunlight or darkness, or at a time at which electricity has high commercial value.
  • a capability to store heat for later use, e.g., to generate electricity on demand, may increase the commercial value of heat collected by operation of the systems and methods.
  • Non-limiting examples of systems and methods for storing heat for subsequent conversion to usable work (e.g., electrical work) that may be used in combination with the systems and methods described herein are described in U.S. Provisional Application
  • One or more performance characteristics of the optical filter that is used to split the solar spectrum and/or one or more performance characteristics of the multiple receivers that are used to receive the discrete wavelength bands of the split solar spectrum may be selected or tuned to increase an overall value of total energy (electrical energy and thermal energy) produced by the systems and methods described herein, over a predetermined time period (e.g., a day, multiple days, a week, multiple weeks, a month, multiple months, a season, multiple seasons, a year, or multiple years).
  • a predetermined time period e.g., a day, multiple days, a week, multiple weeks, a month, multiple months, a season, multiple seasons, a year, or multiple years.
  • ⁇ is a characteristic wavelength of the optical filter that represents a boundary wavelength between the visible band and the infrared band
  • ⁇ may be red-shifted toward the infrared to increase energy output (electrical and/or thermal energy output) from the second receiver, or ⁇ may be blue-shifted toward the visible to increase energy output (electrical and/or thermal energy output) from the first receiver to increase the total commercial value of energy (electrical and heat energy) that is being produced by the first and second receivers combined, integrated over a predetermined time period.
  • a characteristic boundary wavelength ⁇ at which the optical filter splits the solar radiation into at least the visible band and the infrared band may be selected based on any one of or any combination of two or more of the following factors: a) a wavelength dependence of an external quantum efficiency of solar cells in the first receiver, if the first receiver comprises photovoltaic solar cells; b) a wavelength dependence of an external quantum efficiency of solar cells in the second receiver, if the second receiver comprises photovoltaic solar cells; c) the commercial value of heat collected by the first receiver, if the first receiver is configured for collecting heat; and d) the commercial value of heat collected by the second receiver, if the second receiver is configured for collecting heat.
  • the commercial value of heat collected by the first receiver and/or by the second receiver may be increased by storing the heat for later use (e.g., by converting the stored heat to electricity at a time when a value of electricity is increased).
  • the trough reflector utilized in the systems and methods may be any type of linear trough reflector that focuses incident light to an approximately linear focus. In some cases, a parabolic trough reflector is used. In some cases, a cylindrical trough reflector is used.
  • the reflective surface of the trough reflector may be any surface that is capable of providing the desired quality of linear focus. Typically, the reflective surface is continuous, or
  • a reflective surface of the trough reflector may comprise facets, provided the facets are sufficiently small so that a desired linear focus can be achieved.
  • the trough reflector may comprise one or more gaps that do not reflect sunlight, with the gaps corresponding to regions that are shaded by the receivers during operation of the solar energy collector. If present, the gap may be a portion of the trough that has reduced or no reflectivity, or the gap may be a physical gap in the trough where that portion of the reflector is removed and the trough is composed of two sections on either side of the gap.
  • Non-limiting examples of a trough reflector comprising a gap along its longitudinal center are provided in Figures 1-3.
  • the first receiver upon which the visible beam is concentrated may comprise photovoltaic solar cells for generating electricity from the visible beam and/or a solar thermal collector for collecting heat from the visible beam.
  • the first receiver typically comprises solar cells having increased or optimized efficiency for generating usable electricity from the predetermined visible wavelength range of the visible beam.
  • the first receiver comprises a photovoltaic -thermal solar receiver that comprises photovoltaic solar cells that generate usable electricity from the visible band and a solar thermal collector capable of collecting usable heat from the visible band.
  • Solar cells in the first receiver may optionally be passively or actively cooled to maintain the solar cells within a desired range of operating temperatures.
  • the first receiver may be passively cooled by fins or other heat radiating elements that transfer heat to the ambient air.
  • the first receiver and the solar cells may be actively cooled by a heat transfer fluid circulated through channels in the first receiver. Heat collected from the first receiver in this manner may be subsequently transferred to the ambient environment or, if commercially valuable, stored or provided for some external use.
  • the first receiver comprises a solar thermal collector
  • any suitable type of solar thermal collector may be used.
  • the first receiver may comprise one or more fluid channels (e.g., one or more solar absorber pipes) carrying a working fluid to collect heat.
  • a solar selective coating may be applied to one or more components (e.g., solar absorber pipes) of a solar thermal collector to increase heat collection from the visible beam. If used, the solar selective coating may be selected or tuned specifically for use with the visible band.
  • the second receiver upon which the infrared beam is concentrated may comprise a photovoltaic receiver and/or a solar thermal collector.
  • the second receiver comprises a photovoltaic -thermal solar receiver that comprises photovoltaic solar cells that generate usable electricity from the infrared band and a solar thermal collector capable of generating usable heat from the infrared band.
  • a photovoltaic receiver is used in the second receiver, it may comprise solar cells having increased or optimized efficiency for generating electricity from the predetermined infrared wavelength range of the infrared beam.
  • Solar cells used in the second receiver may be passively or actively cooled to maintain the solar cells within a desired range of operating temperatures.
  • the second receiver may be passively cooled by fins or other heat radiating elements that transfer heat to the ambient air.
  • the second receiver and the solar cells may be actively cooled by a heat transfer fluid circulated through channels in the second receiver. Heat collected from the second receiver in this manner may be subsequently transferred to the ambient environment or, if commercially valuable, stored or provided for some external use.
  • the second receiver is or comprises a solar thermal collector, any type of solar thermal collector may be used.
  • a solar receiver may comprise one or more fluid channels (for example, one or more solar absorber pipes) carrying a working fluid to collect heat.
  • a solar selective coating may be applied to one or more components (e.g., solar absorber pipes) of a solar thermal collector to increase heat collection from the infrared beam.
  • a solar selective coating applied to a solar absorber in the second receiver may be selected or tailored for use with the infrared band. It should be understood that a solar selective coating used in the first receiver may be separately tuned or optimized for generating heat from the visible band, and a solar selective coating used in the second receiver may be separately tuned or optimized for generating heat from the infrared band to increase overall performance of the system.
  • the first receiver and/or the second receiver comprises a thermo-electric device.
  • the optical filter that is used to split the solar spectrum into a least a visible band having a predetermined visible wavelength range and an infrared band having a
  • the predetermined infrared wavelength range may be any suitable optical element or combination of optical elements that operates to spatially displace a visible portion of the solar spectrum from an infrared portion of the solar spectrum.
  • the optical filter may comprise a reflector or reflecting prism that selectively transmits visible light and reflects infrared radiation, or a reflector or reflecting prism that selectively transmits infrared and reflects visible.
  • suitable optical filters include dichroic filters, dichroic reflectors, dichroic beam splitters, or dichroic thin film coatings that selectively transmit predetermined wavelengths of light and reflect other wavelengths based on interference.
  • a prism or a diffraction grating may be used to spatially separate visible light from infrared radiation.
  • the optical filter may be or may comprise any type of chromatic dispersion element capable of spatially separating light of visible wavelengths from infrared wavelengths.
  • the predetermined visible wavelength of the split solar spectrum may be any suitable visible wavelength range that allows the first receiver to produce electricity with a desired efficiency, given the intensity of light incident on the photovoltaic receiver, the spectral response of the particular solar cells in the photovoltaic receiver, and the operating temperature.
  • the predetermined visible wavelength band may be from, for example, about 300 nanometers (nm) to about 900 nm, or from about 400 nm to about 900 nm. If the optical filter also produces an ultraviolet band having a predetermined ultraviolet wavelength range, the predetermined ultraviolet wavelength range may be any suitable wavelength range. In some variations, the predetermined ultraviolet wavelength range is any wavelength shorter than about 400 nm, or any wavelength shorter than about 350 nm.
  • the optical filter may be selected, tailored or optimized to split the solar spectrum into wavelength bands having sufficient wavelength overlap with wavelength-dependent external quantum efficiencies of photovoltaic solar cells that may be used in the first and/or second receivers.
  • the first receiver comprises a photovoltaic receiver or a photovoltaic-thermal receiver
  • the optical filter is configured to transmit the visible band and reflect the infrared band, with a wavelength ⁇ representing a boundary between the visible and infrared bands.
  • the wavelength ⁇ may be selected so that the transmitted visible band has increased or optimized wavelength overlap with the wavelength-dependent external quantum efficiency of photovoltaic solar cells in the first receiver.
  • the first receiver comprises a photovoltaic receiver or a photovoltaic -thermal receiver
  • the second receiver comprises a photovoltaic receiver, a photovoltaic -thermal receiver, or a solar thermal receiver.
  • the boundary wavelength ⁇ of the optical filter may be selected according to any one of or any combination of two or more of the following: a) to increase wavelength overlap between the visible band and a wavelength-dependent external quantum efficiency of solar cells in the first receiver; b) to increase wavelength overlap between the infrared band and a wavelength-dependent external quantum efficiency of solar cells in the second receiver, if the second receiver uses solar cells; c) to increase electrical output from the first receiver; d) to increase electrical output from the second receiver, if the second receiver is configured for generating electricity; e) to increase heat output from the first receiver, if the first receiver is capable of generating heat; f) to increase heat output from the second receiver, if the second receiver is capable of generating heat; g) to increase or optimize combined electrical outputs
  • the first receiver may be any type of receiver capable of generating heat and/or electricity from the visible band having the predetermined visible wavelength range.
  • the first receiver may comprise any one of or any combination of two or more of the following: a photovoltaic receiver, a solar thermal receiver, and a thermoelectric device.
  • a photovoltaic receiver may comprise any one of or any combination of two or more of the following: a photovoltaic receiver, a solar thermal receiver, and a thermoelectric device.
  • any type of solar cells may be used in a photovoltaic or photovoltaic -thermal first receiver that is used to convert the visible band to electricity.
  • Solar cells may be single junction cells, multi-junction cells, or heterojunction cells. Solar cells may be constructed from any suitable material to have an appropriate band gap to generate usable electricity with the desired efficiency at the intended operating temperature.
  • a photovoltaic receiver may utilize more than one type of solar cell in some applications.
  • Non-limiting examples of suitable solar cells that may be used in the first receiver include commercially available crystalline silicon solar cells (useful spectral response from about 400 nm to about 1 100 nm), amorphous silicon solar cells (useful spectral response from about 400 nm to about 800 nm), GaAsAl solar cells (useful spectral response from about 400 nm to about 900 nm), and GaAs solar cells (useful spectral response from about 400 nm to about 900 nm), and InGaP solar cell (useful spectral from 350nm to 700nm.
  • the predetermined infrared wavelength range of the infrared portion of the split solar spectrum may be any suitable infrared wavelength range that allows the second receiver to produce electricity and/or heat with a desired efficiency, given the intensity of light incident on the second receiver, and the type of receiver (e.g., solar thermal, photovoltaic, photovoltaic-thermal, or thermoelectric).
  • the predetermined infrared wavelength range is any wavelength longer than about 700 nm, or any wavelength longer than about 800 nm, or any wavelength longer than about 900 nm.
  • the second receiver may be any type of receiver capable of generating heat and/or electricity from the infrared band having the predetermined infrared wavelength range.
  • the second receiver may comprise any one of or any combination of two or more of the following: a photovoltaic receiver, a solar thermal receiver, and a thermoelectric device. If a photovoltaic receiver is used, it may comprise solar cells having increased or optimized efficiency for generating useful electricity from the predetermined infrared wavelength range of the infrared beam. Any suitable type of photovoltaic solar cells may be used in a photovoltaic or photovoltaic -thermal second receiver, where the type of solar cells may be selected based on the boundary wavelength ⁇ between the visible band and the infrared band.
  • ⁇ may be selected to be about 700 nm, where the visible band comprises wavelengths shorter than about 700 nm, and the infrared band comprises wavelengths longer than about 700 nm.
  • a photovoltaic or photovoltaic -thermal second receiver may comprise Si solar cells.
  • the first receiver may comprise a photovoltaic -thermal solar receiver and the second receiver may comprise a solar thermal collector or a photovoltaic -thermal solar receiver.
  • the first receiver comprises one or more fluid channels for carrying a working fluid.
  • the first receiver collects heat from the visible beam, and this heat is used to preheat the working fluid.
  • Heat generated in the second receiver from the infrared beam is used to boost the heat of the working fluid that has been preheated in the first receiver.
  • the fluid channels of the first receiver are in fluid communication with fluid channels of the second receiver, and the working fluid that has been preheated in the first receiver is directed to fluid channels in the second receiver, where it is further heated by the infrared beam.
  • a heat content of the preheated working fluid is boosted via heat exchange with a working fluid heated by the infrared beam in the second receiver.
  • the first receiver comprises a photovoltaic -thermal solar receiver
  • the visible beam may be used to generate electricity as well as to preheat the working fluid
  • the second receiver comprises a photovoltaic- thermal solar receiver
  • the infrared beam may be used to generate electricity as well as to boost heat of the preheated working fluid.
  • the systems and methods utilize a focusing trough reflector to concentrate the solar radiation. Because the optical filter splits the solar spectrum to provide spatially displaced visible and infrared beams, the degree of concentration of the visible light and the infrared radiation may be varied independently. Radiation concentration at the first receiver may be controlled by placement of the first receiver relative to the focus of the visible beam, and radiation concentration at the second receiver may be controlled by placement of the second receiver relative to the focus of the infrared beam. In some variations of the systems and methods, the visible beam is focused on the first receiver, so that the visible radiation is concentrated at the first receiver. In some variations of the systems and methods, the visible beam is not focused on the first receiver.
  • the first receiver is positioned to receive the visible beam at a location where it is not focused, for example to reduce heating of the solar cells and/or to reduce optical damage to the photovoltaic receiver.
  • the infrared beam is focused on the second receiver so that infrared radiation is concentrated at the second receiver. Focusing of the infrared radiation on the receiver may be especially appropriate when the second receiver is a solar thermal receiver.
  • the infrared beam is not focused on the second receiver, and instead the second receiver is positioned to receive the infrared beam at a location where it is not focused.
  • Such a configuration may be used, for example, when the second receiver comprises a photovoltaic receiver to reduce heating or damage of infrared-sensitive solar cells.
  • the visible beam is focused on the first receiver and the infrared beam is focused on the second receiver. In some variations, the visible beam is not focused on the first receiver and the infrared beam is focused on the second receiver. In some variations, the visible beam is focused on the first receiver and the infrared beam is not focused on the second receiver. In some variations, the visible beam is not focused on the first receiver and the infrared beam is not focused on the second receiver.
  • the systems and methods may utilize one or more additional optical elements for redirecting, filtering, diffusing and/or focusing the visible and/or infrared beams.
  • the optical filter may be positioned in any suitable position relative to the reflector and the first and second receivers. In some cases, the optical filter is positioned adjacent to the receiving surface of the first receiver. In some cases, the optical filter is positioned adjacent to the receiving surface of the second receiver. In some cases, the optical filter comprises a thin film dichroic coating applied to a receiving surface of the first receiver, where the thin film selectively transmits the visible portion of the solar spectrum to the first receiver and selectively reflects the infrared portion of the spectrum to be separately directed to the second receiver.
  • the optical filter comprises a thin film dichroic coating applied to a receiver surface of the second receiver, where the thin film dichroic coating selectively transmits the infrared portion of the solar spectrum to the second receiver (e.g., where the second receiver comprises a photovoltaic receiver) and selectively reflects the visible portion of the solar spectrum to be separately directed to the first receiver.
  • a solar energy collection system 100 comprises a trough reflector 110.
  • the trough reflector 1 10 may be a parabolic or cylindrical reflector.
  • the reflector 1 10 may be divided into two sections as illustrated in Figure 1, with a physical gap 120 centered at the low point of the trough 110 (e.g., vertex for a parabolic trough) and extending longitudinally along its length (perpendicular to the cross-sectional view in Figure 1). This gap may correspond to a region shaded by the receivers during operation of the solar energy collector.
  • the trough reflector 110 is a continuous structure without gap 120. Incident solar radiation (indicated by rays 105) is reflected by the trough reflector 110. The reflected concentrated rays 115 are incident on an elevated optical filter 140.
  • the optical filter 140 splits the solar spectrum to produce at least a visible band having a predetermined visible wavelength range and an infrared band having a predetermined infrared wavelength range.
  • the optical filter 140 transmits the visible beam (indicated by rays 125) to a receiving surface of an elevated first receiver 150.
  • First receiver 150 may be a photovoltaic receiver that is capable of generating useful electricity from the visible band, or a photovoltaic -thermal receiver that is capable of generating electricity and heat from the visible band.
  • the optical filter 140 reflects the infrared beam (indicated by rays 135) to the second receiver 160.
  • second receiver 160 is a solar thermal collector that generates heat from the infrared beam reflected by the optical filter.
  • Filter 140 may also reflect an ultraviolet beam to second receiver 160.
  • a receiving surface of the first receiver 150 is located approximately at the linear focus of the visible beam.
  • the linear focus of the visible beam corresponds approximately to the linear focus of the trough reflector 110.
  • the second receiver is located approximately at the linear focus of the infrared beam.
  • the second receiver may be or may comprise a solar absorbing pipe, as illustrated in Figure 1, so that the linear focus of the infrared beam may be positioned approximately at a longitudinal center of the solar absorbing pipe.
  • the reflector, optical filter and first and second receivers may be mounted on a frame that is rotated to track the sun.
  • the reflector, optical filter, and first and second receivers may be rotated together to track the sun.
  • any one of the first receiver, optical filter, and second receiver may be rotated or positioned
  • a solar energy collection system comprises a first receiver capable of generating useful electricity from the visible beam and a second receiver capable of generating useful electricity from the infrared beam.
  • a solar energy collection system 200 comprises a trough reflector 210.
  • the trough reflector 210 may be a parabolic or cylindrical reflector.
  • the reflector 210 may be divided into two sections as illustrated in Figure 2, with a physical gap 220 centered at the low point of the trough 210 (e.g., vertex for a parabolic trough) and extending longitudinally along its length (perpendicular to the cross-sectional view in Figure 2).
  • the gap may correspond to regions shaded by the receivers during operation of the solar energy collector.
  • the trough reflector 210 is a continuous structure without gap 220.
  • Incident solar radiation (shown by downward directed rays 205) is reflected by the trough reflector 210.
  • the concentrated reflected rays 215 are incident on an elevated optical filter 240.
  • the optical filter 240 splits the solar spectrum to produce at least a visible band having a predetermined visible wavelength range and an infrared band having a predetermined infrared wavelength range.
  • the optical filter 240 transmits the visible beam (indicated by rays 225) to an elevated first receiver 250.
  • First receiver 250 may be a photovoltaic receiver capable of generating electricity from the visible beam, or a photovoltaic-thermal receiver capable of generating electricity and heat from the visible beam.
  • the optical filter 240 reflects the infrared beam (indicated by rays 235) to a second receiver 260.
  • Second receiver 260 may be a photovoltaic receiver capable of generating electricity from the infrared beam, or a photovoltaic -thermal receiver capable of generating electricity and heat from the infrared beam.
  • Filter 240 may also reflect an ultraviolet beam to the second receiver.
  • a receiving surface of the first receiver 250 is located approximately at the linear focus of the visible beam.
  • the linear focus of the visible beam corresponds approximately to the linear focus of the trough reflector 210.
  • a receiving surface of the second receiver is located approximately at the linear focus of the infrared beam.
  • the reflector, optical filter and first and second receivers may be mounted on a frame that may be rotated to track the sun.
  • the reflector, optical filter, and first and second receivers may be rotated together to track the sun.
  • any one of the first receiver, optical filter, and second receiver may be rotated or positioned independently of each other or independently of the trough reflector to increase collection efficiency.
  • typical relative dimensions (in millimeters) for the various components for one particular example of solar energy collection system 200 are provided in Figure 2, any suitable relative dimensions may be used.
  • a solar energy collection system comprises a first receiver capable of generating useful electricity from the visible beam, where the visible beam is not fully concentrated (i.e., not completely focused on) a receiving surface of the first receiver.
  • a solar energy collection system 300 comprises a trough reflector 310.
  • the trough reflector 310 may be a parabolic or cylindrical reflector.
  • the reflector 310 may be divided into two sections as illustrated in Figure 1, with a physical gap 320 centered at the low point of the trough 310 (e.g., vertex for a parabolic trough) and extending longitudinally along its length (perpendicular to the cross-sectional view in Figure 3).
  • the gap may correspond to regions shaded by the receivers during operation of the solar energy collector.
  • the trough reflector 310 is a continuous structure without gap 320.
  • Incident solar radiation (shown by downward directed arrows 305) is reflected by the trough reflector.
  • Concentrated reflected rays 315 are incident on an elevated optical filter 340.
  • the optical filter 340 splits the solar spectrum to produce at least a visible band having a predetermined visible wavelength range and an infrared band having a predetermined infrared wavelength range.
  • the optical filter 340 transmits the visible beam (indicated by rays 325) to an elevated first receiver 350.
  • First receiver 360 may be a photovoltaic receiver that is capable of generating useful electricity from the visible band, or a photovoltaic-thermal receiver that is capable of generating electricity and heat from the visible band.
  • the optical filter 340 reflects the infrared beam (indicated by rays 335) to a second receiver 360. Filter 340 may also reflect an ultraviolet beam to the second receiver.
  • a receiving surface of the first receiver 350 is positioned in a somewhat defocused region of the visible beam (rays 325) before the linear focus F 1 of the visible beam, which corresponds approximately to the linear focus of trough reflector 310, and extends perpendicularly to the cross-sectional view of Figure 3.
  • the receiver 350 may be positioned in the visible beam beyond the focus F l of the visible beam, so that the visible beam incident on the receiver 350 is somewhat defocused.
  • the second receiver 360 is located approximately at the linear focus of the infrared beam.
  • the second receiver may be or may comprise a solar absorber pipe, as illustrated in Figure 3, so that the linear focus of the infrared beam may be positioned approximately at a longitudinal center of the pipe.
  • the second receiver may be a photovoltaic receiver or a photovoltaic -thermal receiver.
  • the second receiver may be positioned at the linear focus of the infrared beam to receive the most concentrated radiation, or alternatively, positioned before or after the focus of the infrared beam to receive less concentrated radiation.
  • the reflector, optical filter and first and second receivers may be mounted on a frame that may be rotated to track the sun.
  • the reflector, optical filter, and first and second receivers may be rotated together to track the sun.
  • any one of the first receiver, optical filter, and second receiver may be rotated or positioned independently of each other or independently of the trough reflector to increase collection efficiency.
  • typical relative dimensions (in millimeters) for the various components of the particular example of a solar energy collection system 300 are provided in Figure 3, any suitable relative dimensions may be used.
  • the optical filter may be a thin film dichroic coating applied to a receiving surface of the first receiver or second receiver (e.g., if the second receiver is or comprises an infrared sensitive photovoltaic receiver).
  • a solar energy collection system 400 comprises a trough reflector 410.
  • the trough reflector 410 may be a parabolic or cylindrical reflector.
  • reflector 410 is illustrated as a continuous reflector in Figure 4, optionally, the reflector 410 may be divided into two sections as illustrated in Figure 3, with a longitudinally extending gap positioned at the low point of the reflector 410. The gap may correspond to regions shaded by the receivers during operation of the solar energy collector.
  • Incident solar radiation (shown by downward directed rays 405) is reflected by the trough reflector 410.
  • the reflected concentrated rays 415 are incident on an optical filter 440 which is a thin film dichroic coating applied to a receiving surface of an elevated first receiver 450.
  • the optical filter 440 splits the solar spectrum to produce at least a visible band having a predetermined visible wavelength range and an infrared band having a predetermined infrared wavelength range.
  • the optical filter 440 transmits the visible beam to the first receiver 450.
  • First receiver 450 may be a photovoltaic receiver that is capable of generating useful electricity from the visible band, or a
  • the optical filter 440 reflects the infrared beam (indicated by rays 435) to a second receiver 460. Filter 440 may also reflect an ultraviolet beam to the second receiver.
  • a receiving surface of the first receiver 450 is located before the linear focus Fl of the visible beam, so that the intensity of visible light on the receiver 450 is reduced.
  • the first receiver 450 is positioned beyond the focus Fl to receive defocused visible light, or positioned at the focus Fl to receive the most concentrated visible light.
  • the second receiver is located approximately at the linear focus of the infrared beam.
  • the second receiver may be or may comprise a solar absorber pipe, as illustrated in Figure 4, so that the linear focus of the infrared beam may be positioned approximately at a longitudinal center of the solar absorber pipe.
  • the second receiver may be a photovoltaic receiver capable of generating useful electricity from the infrared band, or a photovoltaic -thermal receiver capable of generating electricity and heat from the infrared band.
  • the second receiver may be positioned at the linear focus of the infrared beam to receive the most concentrated radiation, or alternatively, positioned before or after the focus of the infrared beam to receive less concentrated radiation.
  • the reflector, optical filter and first and second receivers may be mounted on a frame that may be rotated to track the sun.
  • the reflector, optical filter, and first and second receivers may be rotated together to track the sun.
  • any one of the first receiver, optical filter, and second receiver may be rotated or positioned independently of each other or independently of the trough reflector to increase collection efficiency.
  • the trough reflector in the solar energy collection systems described herein can be mounted on any type of frame or support.
  • the trough reflector can be mounted on a space frame or a torque tube.
  • a system includes a rotation mechanism to automatically rotate the reflector to track the sun.
  • the first receiver, the optical filter and the second receiver are mounted in such a manner that the receivers and the optical filter rotate together with the trough reflector. In other cases, one or more of the receivers and/or the optical filter do not rotate with the trough reflector.
  • one or more of the receivers and/or the optical filter are controlled by a rotation control that allows them to be rotated independently of the trough reflector. In some cases, the receivers and the optical filter rotate together with the reflector, and one or more of the receivers and/or the optical filter is controlled by an additional rotational control that allows for rotation independent of the trough reflector.
  • the optical filter may produce more than one visible beam or more than one infrared beam
  • two or more (e.g., identical) optical filters may produce two or more visible beams and/or two or more infrared beams
  • one or more beam splitters may be employed to produce multiple visible beams from a single visible beam produced by the optical filter
  • one or more beam splitters may be employed to produce multiple infrared beams from a single infrared beam produced by the optical filter.
  • a system may comprise multiple visible photovoltaic receivers, where each visible receiver receives one or more of the multiple visible beams, or multiple infrared receivers (photovoltaic and/or solar thermal), where each infrared receiver receives one or more of the multiple infrared beams.
  • an optical filter may be configured as a "V" shape, transmit the visible band through the V-shaped filter, and reflect two infrared beams, with one infrared beam directed outward and downward towards one outside edge 380 of reflector 310 and the other infrared beam directed outward and downward towards an opposite outside edge 381 of reflector 310.
  • Two parallel solar absorber pipes perpendicular to the plane of the page may be placed near the edges 380 and 381 of the reflector.
  • a vertical position of the V-shaped filter may be adjusted to focus the two infrared beams on the parallel solar absorbing tubes.
  • first receiver and the second receiver are depicted as elevated relative to the trough reflector in Figures 1-4, other variations are contemplated in which the first receiver, the second receiver, or both the first and second receivers may be positioned at approximately the same vertical height as the trough reflector, or at a lower vertical height than the trough reflector. Further, other variations are contemplated in which a first and/or second receiver is positioned outside a direct reflection region of the trough reflector (e.g., outside the region defined by rays 415 in Figure 4).
  • the first receiver, onto which visible light is concentrated, is typically a
  • the first receiver may optionally be passively or actively cooled to maintain the solar cells within a desired range of operating temperatures.
  • the first receiver may be passively cooled by fins or other heat radiating elements that transfer heat to the ambient air.
  • the first receiver and the solar cells may be actively cooled by a heat transfer fluid circulated through channels in the receiver. Heat collected from the first receiver in this manner may be subsequently transferred to the ambient environment or, if commercially valuable, stored or provided for some external use.
  • the second receiver onto which infrared solar energy is concentrated
  • the second receiver may be similarly actively or passively cooled.
  • the first receiver is a solar thermal receiver configured for generating only heat from the visible light.
  • the systems and methods described herein may employ any one of the following configurations: the first receiver is a solar thermal receiver capable of generating heat from the visible beam and the second receiver comprises photovoltaic solar cells capable of generating electricity from the infrared beam; the first receiver is a solar thermal receiver capable of generating heat from the visible beam and the second receiver comprises a photovoltaic -thermal solar receiver capable of generating electricity and heat from the infrared beam; or the first receiver is a solar thermal receiver capable of generating heat from the visible beam and the second receiver comprises a solar thermal receiver capable of generating heat from the infrared beam.
  • a solar energy collector system may comprise multiple single reflector/first receiver/optical filter/second receiver modules, which may be arranged in a variety of configurations. For example, a series of multiple single reflector/first
  • receiver/optical filter/second receiver modules may be arranged lengthwise to form a row of modules. In some cases, multiple rows of modules may be arranged to form a solar energy collector. The modules may be coupled together in any manner to collect electrical energy produced by photovoltaic cells and heat collected by heat transfer fluid flowing through solar thermal receivers.
  • heat that is generated may be stored.
  • Stored heat may be used as heat, or optionally converted to mechanical or electrical work.
  • the stored heat may provide a source of dispatchable energy that may be used, for example, during periods of low sunlight, high demand, or periods when the energy has increased commercial value.
  • Non-limiting examples of heat storage systems and methods that may be used with the solar energy collection systems and methods described herein are provided in U.S.
  • Provisional Patent Application 61/845,541 filed July 12, 2013 and entitled “Photovoltaic- Thermal Solar Energy Collection System With Energy Storage”; and U.S. Provisional Patent Application 61/860,720 filed July 31, 2013 and entitled “Solar Energy Collection System with Energy Storage”, each of which is incorporated by reference herein in its entirety as if put forth fully below.
  • Non-limiting examples of suitable photovoltaic -thermal solar energy collectors that may be employed with the systems, apparatus and methods disclosed herein are described in the following publications: U.S. Patent Application 12/712, 122 filed February 24, 2010 and entitled “Designs for 1-D Concentrated Photovoltaic Systems”; U.S. Patent Application 12/788,048 filed May 26, 2010 and entitled “Concentrating Solar Photovoltaic-Thermal Systems”; U.S. Patent Application 12/622,416 filed November 19, 2009 and entitled “Receiver for Concentrating Solar Photovoltaic-Thermal System”; U.S. Patent Application 12/774,436 filed May 5, 2010 and entitled “Receiver for Concentrating Solar Photovoltaic- Thermal System; U.S.
  • Patent Application 12/781,706 filed May 17, 2010 and entitled “Concentrating Solar Energy Collector”; U.S. Patent Application 13/079, 193 filed April 4, 2011 and entitled “Concentrating Solar Energy Collector”; U.S. Patent Application 13/291,531 filed November 8, 2011 and entitled “Photovoltaic-Thermal Solar Energy Collector with Integrated Balance of System”; U.S. Patent Application 13,371,790 filed February 13, 2012 and entitled “Solar Cell with Metallization Compensating for or

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Abstract

Systèmes, procédés et appareil permettant de collecter l'énergie solaire pour fournir de l'électricité et/ou de la chaleur.
PCT/US2014/051939 2013-08-27 2014-08-20 Collecteur d'énergie solaire à spectre divisé WO2015031135A1 (fr)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5902417A (en) * 1996-12-12 1999-05-11 Hughes Electornics Corporation High efficiency tandem solar cells, and operating method
US20070107769A1 (en) * 2005-12-19 2007-05-17 Cobb Joshua M Apparatus for obtaining radiant energy
US20080276929A1 (en) * 2007-03-06 2008-11-13 Dave Gerwing Solar collector
US20100319684A1 (en) * 2009-05-26 2010-12-23 Cogenra Solar, Inc. Concentrating Solar Photovoltaic-Thermal System

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5902417A (en) * 1996-12-12 1999-05-11 Hughes Electornics Corporation High efficiency tandem solar cells, and operating method
US20070107769A1 (en) * 2005-12-19 2007-05-17 Cobb Joshua M Apparatus for obtaining radiant energy
US20080276929A1 (en) * 2007-03-06 2008-11-13 Dave Gerwing Solar collector
US20100319684A1 (en) * 2009-05-26 2010-12-23 Cogenra Solar, Inc. Concentrating Solar Photovoltaic-Thermal System

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