WO2010132955A1

WO2010132955A1 - Apparatus, system and method for photosynthesis

Info

Publication number: WO2010132955A1
Application number: PCT/AU2010/000617
Authority: WO
Inventors: Scott R. Edwards; Ian S. Fitzpatrick
Original assignee: Omega 3 Innovations Pty Ltd
Priority date: 2009-05-21
Filing date: 2010-05-21
Publication date: 2010-11-25

Abstract

A photosynthetic growth apparatus including: photosynthetic material defining a preferred photosynthesis absorption band of optical wavelengths for performing photosynthesis; and a wavelength converter for emitting growth light in the preferred photosynthesis absorption band, for absorption by the photosynthetic material, by absorbing solar radiation in a converter absorption band different to the preferred photosynthesis absorption band, based on Stokes fluorescence.

Description

APPARATUS, SYSTEM AND METHOD FOR PHOTOSYNTHESIS

FIELD

The present invention relates to apparatuses, systems and methods for providing photosynthesis, for example for growing algae with a photobioreactor (PBR).

BACKGROUND

The climate of planet Earth is changing as increasing volumes of carbon dioxide (CO2) accumulate in the environment, in particular the atmosphere, lakes and oceans. Much of the CO2 released into the environment is generated by technologies and industries that have become important to national economies and people's way of life. For example, coal- fired electricity generation plants provide cheap electricity that is essential for modern society, but are increasingly under pressure to reduce the amount of CO2 they emit into the atmosphere. Governments and companies are in desperate need to reduce the amount of CO2 being released into the environment, and to reduce the amount of CO2 already released, using so-called "carbon capture" techniques. For example, photosynthetic growth captures CO2 to build structures of plants, such as its biological cells. However, there is insufficient growing photosynthetic matter (e.g., plants on land and in the ocean) on Earth, or at least insufficient photosynthetic matter that is conveniently located, to capture enough CO2 to reverse its accumulation in the environment at current rates of emission.

There is a need for an increase in the Earth's capacity to capture CO2, including a need for more photosynthetic material performing photosynthesis, and more efficient use of available solar radiation in photosynthesis, in particular using solar radiation directly, in more efficient facilities. There is a need to provide high-efficiency photosynthesis concentrated in particular locations, e.g., near CO2-emitting facilities. There is a need for containing photosynthetic materials in non-contaminating facilities, e.g., through ingress or egress of materials / pollutants. There is a need for more robust and simpler apparatuses for supporting photosynthesis.

It is desired to address or ameliorate one or more of the problems, disadvantages and limitations associated with the prior art, or to at least provide a useful alternative.

SUMMARY

In accordance with the present invention, there is provided a photosynthetic growth apparatus including: at least one solar collector configured to collect solar radiation; at least one growth area configured for photosynthetic material to perform photosynthesis using radiation having at least one selected wavelength; a wavelength converter configured to convert at least a portion of the collected solar radiation having at least one wavelength different from the at least one selected wavelength to radiation with the at least one selected wavelength for the photosynthetic material; and a light modulator configured to control irradiation of the photosynthetic material by the radiation with the at least one selected wavelength to at least substantially reduce photoinhibition of the photosynthesis.

In some embodiments, the irradiation of the photosynthetic material uses light arising from the solar radiation.

In some embodiments, the light modulator modulates the amplitude of the irradiation of the photosynthetic material. In some embodiments, the light modulator modulates the amplitude of the irradiation between zero and a maximum.

In some embodiments, the light modulator includes a distributor configured to distribute the collected radiation and the converted radiation between a plurality of different portions of the photosynthetic material in the at least one growth area. In some embodiments, the distributor includes a moving distributor configured to selectively and sequentially direct the collected radiation and the converted radiation to the plurality of different portions of the photosynthetic material. In some embodiments, the moving distributor is a rotating distributor including a rotating reflector. In some embodiments, the moving distributor is a switching distributor including a plurality of switching reflectors. In some embodiments, the plurality of different portions of the photosynthetic material are in respective different growth areas of the at least one growth area.

In some embodiments, the light modulator is controlled by a modulation controller to control the intensity at a selectable maximum intensity, minimum intensity, modulation frequency, and/or modulation duty cycle. In some embodiments, the modulation frequency is about 1 Hz to 20 kHz, or about 25 Hz to 250 Hz. In some embodiments, the duty cycle is between about 10% and about 50%.

In some embodiments, the light modulator is controlled by a modulation controller to control the intensity to at least substantially reduce self-shadowing of the photosynthetic material due to excessive growth of the photosynthetic material.

In some embodiments, the at least one solar collector includes at least one reflective surface for concentrating the solar radiation. In some embodiments, the at least one reflective surface is moveable to track movement of the sun. In some embodiments, the at least one reflective surface is fixed relative to movement of the sun, and the at least one solar collector includes at least one respective tilting arm receiver moveable to track movement of the concentrated solar radiation caused by movement of the sun. In some embodiments, the at least one solar collector forms a fixed roofing structure, and the at least one reflective surface concentrates the solar radiation to a radiation capture device substantially protected from environmental and mechanical damage. In some embodiments, the at least one reflective surface includes two surfaces, and the first surface is shaped to concentrate the solar radiation to the receiver behind the second surface. In some embodiments, the first surface has a compound parabolic concentrator shape.

In some embodiments, the at least one selected wavelength includes one or more wavelengths respectively corresponding to one or more of the lowest photosynthetic absorption states of the photosynthetic material. In some embodiments, the at least one selected wavelength includes one or more wavelengths corresponding to red light. In some embodiments, the red light includes wavelengths from about 620 nm to about 780 nm. In some embodiments, the red light includes wavelengths from about 660 nm to about 750 nm. In some embodiments, the photosynthetic growth apparatus includes an artificial light source configured to generate artificial radiation having at least one selected wavelength for irradiating the photosynthetic material to perform photosynthesis when the solar radiation is not available, to at least substantially reduce respiration by the photosynthetic material. In some embodiments, the artificial light source includes light-emitting diodes (LEDs) emitting red light. In some embodiments, the artificial light source is powered by electricity generated photovoltaicly from portions of the solar radiation not including the at least one selected wavelength.

In some embodiments, the photosynthetic growth apparatus includes a light guide configured to receive and guide the collected radiation and the converted radiation from the solar collector to the photosynthetic material. In some embodiments, the light guide includes a plurality of reflector elements for receiving the collected radiation from a first direction and for directing the received radiation in a second direction generally perpendicular to the first direction. In some embodiments, each reflector element includes two curved reflective faces with an open end for receiving the collected radiation, and wherein a first curved reflective face is shaped to direct radiation behind a second curved reflective face at a narrow end of the reflector element. In some embodiments, the light guide includes a plurality of wavelength convertor elements of the wavelength convertor for converting the portion of the solar radiation as the collected radiation is guided by the light guide. In some embodiments, the light guide is configured to separate the wavelength convertor and/or the at least one solar collector from the photosynthetic material to at least substantially reduce any effect of heat from the wavelength convertor and/or the at least one solar collector on the photosynthetic material. In some embodiments, the light guide includes a plurality of light panels to spatially distribute light across the at least one growth area.

In some embodiments, the at least one growth area includes at least one growth chamber configured to transmit the collected radiation and the converted radiation from the light guide to the photosynthetic material. In some embodiments, the at least one growth chamber includes a plurality of transparent side walls. In some embodiments, the at least one growth chamber is configured to allow fluid flow to and from the photosynthetic material. In some embodiments, the at least one growth chamber is in the form of a replaceable container. In some embodiments, sparging features are integrally formed in the replaceable container. In some embodiments, the sparging features include perforations between separate compartments of the at least one growth chamber.

In some embodiments, the photosynthetic growth apparatus includes at least one wavelength separator configured to separate portions of the solar radiation that do not have the at least one selected wavelength for use in heat generation and/or photovoltaic electricity generation. In some embodiments, the photosynthetic growth apparatus includes at least one wavelength separator having at least one wavelength-selective surface configured to separate portions of solar radiation having the at least one selected wavelength from portions not having the at least one selected wavelength. In some embodiments, the at least one wavelength-selective surface includes a dichroic reflective coating.

In some embodiments, the wavelength converter uses Stokes fluorescence to convert the solar radiation. In some embodiments, the photoluminescence is provided by a semiconductor material, and the semiconductor material includes a plurality of semiconductor quantum dots (QDs). In some embodiments, the converted radiation has a wavelength based on a morphology and/or dielectric environment of the QDs.

In some embodiments, the photosynthetic material includes microalgae.

The present invention also provides a photosynthetic growth system including: the photosynthetic growth apparatus; and a fluidic processing system for supplying the photosynthetic material with input matter for the photosynthesis.

The present invention also provides a photosynthetic growth facility for capturing carbon dioxide using photosynthesis including: a plurality of the photosynthetic growth systems; and a control system for controlling the photosynthetic growth apparatuses and the fluidic processing systems. In some embodiments, the at least one solar collector includes an array of solar collectors forming a roof. In some embodiments, the roof is substantially sealed to fluid and/or temperature.

The present invention also provides a method of performing photosynthesis including the steps of: collecting solar radiation; converting at least a portion of the collected solar radiation having one or more wavelengths different from at least one selected wavelength to radiation with the at least one selected wavelength; performing photosynthesis using photosynthetic material and the radiation having the at least one selected wavelength; and controlling irradiation of the photosynthetic material by the radiation having the at least one selected wavelength to at least substantially reduce photoinhibition of the photosynthesis.

The present invention also provides a method of performing photosynthesis including the steps of: collecting solar radiation; converting a portion of the solar radiation that does not have at least one preferred wavelength for photosynthesis by a photosynthetic material into light having at least one preferred wavelength; controlling the intensity of the collected radiation and the converted radiation to at least substantially reduce photoinhibition of the photosynthesis; and performing the photosynthesis using the collected radiation and the converted radiation.

The present invention also provides a photosynthetic growth apparatus including: at least one solar collector configured to collect solar radiation; a wavelength converter configured to convert a portion of the solar radiation that does not have at least one preferred wavelength for photosynthesis by a photosynthetic material into radiation having at least one preferred wavelength for photosynthesis by the photosynthetic material; a light modulator configured to control the intensity of the collected radiation and the converted radiation to at least substantially reduce photoinhibition of the photosynthesis; and photosynthetic material for performing the photosynthesis using the collected radiation and the converted radiation.

The present invention also provides a solar collector including: at least one reflector, fixed relative to movement of the sun, configured to concentrate solar radiation to a moving region; and at least one moving receiver configured to move to receive the concentrated solar radiation in the region.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present invention are hereinafter further described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a block diagram of a photosynthetic growth system;

Figure 2 is a diagram of a perspective view of a photosynthetic growth apparatus of the photosynthetic growth system;

Figure 3 A is a schematic diagram of a perspective view of an optical system of the photosynthetic growth apparatus;

Figure 3 B is a diagram of a perspective view of the optical system;

Figure 3C is a schematic diagram of a cross-sectional view of a tracking collector of the optical system;

Figure 4 is a diagram of a perspective view of a distributor and a light guide of the optical system;

Figure 5 is a schematic diagram of a perspective view of a reflector and a lamp in the optical system;

Figure 6 is a schematic diagram of a cross-sectional view of a switching device of the distributor;

Figure 7A is a diagram of a plurality of light panels of the optical system; Figure 7B is a schematic diagram of a switching distributor of the optical system;

Figure 8 is a diagram of a perspective view of a photosynthetic growth chamber of the photosynthetic growth apparatus;

Figure 9 is a diagram of a perspective view of an array of a plurality of the photosynthetic growth chambers;

Figure 10 is a diagram of a perspective view of a frame of the photosynthetic growth apparatus;

Figure 11 is a diagram of a perspective view of a photosynthetic growth facility including a plurality of the photosynthetic growth systems;

Figure 12 is a schematic diagram of a fluidic system of the photosynthetic growth system;

Figure 13 is a schematic diagram of a profile of a guide element of a waveguide assembly of the optical system;

Figure 14 is a schematic diagram of a side view of the waveguide assembly;

Figure 15 is a diagram of a perspective view of a tilting-arm collector of the optical system;

Figure 16 is a diagram of a perspective view of an array of tilting-arm collectors;

Figures 17A to 17E are schematic diagrams of side views of the tilting-arm collector in different positions;

Figure 17F is a chart of collection efficiency as a function of the angle of incident solar radiation;

Figure 18 is a schematic diagram of a profile of a concentrating collector of the optical system;

Figures 19A to 19C are diagrams of perspective views of arrays of the concentrating collectors; and

Figure 19D is a diagram of a perspective view of a facility including an array of the concentrating collectors. DETAILED DESCRIPTION

Overview

As shown in Figure 1, a photosynthetic growth system 100 includes at least one solar collector 102 configured to collect solar radiation 104, a wavelength separator 106 for separating the solar radiation 104 into components (or "ports") based on their wavelengths and including preferred radiation 108 (including selected preferred wavelengths for photosynthesis) and non-preferred radiation 100 (including non-preferred wavelengths, and not including the selected wavelengths). The at least one solar collector 102 includes at least one reflective surface for concentrating the solar radiation.

The photosynthetic growth system 100 includes at least one growth area, including one or more growth chambers 116, configured for photosynthetic material to perform photosynthesis using the preferred radiation 108 (i.e., radiation having at least one of selected preferred wavelength).

The photosynthetic growth system 100 includes a wavelength converter 112 configured to convert at least a portion of collected solar radiation having at least one wavelength different from the at least one selected preferred wavelength (also referred to as the non- preferred radiation 1 10) into radiation with the at least one selected wavelength for the photosynthetic material (also referred to as additional preferred radiation 108). The photosynthetic growth system 100 includes a light modulator configured to control irradiation of the photosynthetic material by the radiation with the at least one selected wavelength (the preferred radiation 108) to at least substantially reduce photoinhibition of the photosynthesis. Modulating the irradiation includes modulating the amplitude of the irradiation of the photosynthetic material, e.g., zero and a maximum amplitude, and can be referred to as "flashing" the irradiation (or growth light), or photomodulating the light.

The photosynthetic growth system 100 includes a light guide 113 for guiding light to the modulator. The light guide 1 13 is configured to receive and guide the collected radiation and the converted radiation from the solar collector 102 to the photosynthetic material. The light guide 1 13 is configured to separate the wavelength convenor 112 and/or the at least one solar collector 102 from the photosynthetic material in the growth area(s) to at least substantially reduce any effect of heat from the wavelength convertor 112 and/or the at least one solar collector 102 on the photosynthetic material: the temperature of the photosynthetic material may need to be controlled at a level insulated from extremes of temperature in the wavelength convertor 1 12 and/or the solar collector 102 due to heat generated in the conversion process, or heat due to absorption of the collected solar radiation, respectively.

The light modulator can include a distributor 1 14, as shown in Figure 1, configured to distribute the collected radiation and the converted radiation between a plurality of different portions of the photosynthetic material in the at least one growth area. The distributor 114 directs the preferred radiation 108 (including the collected radiation and the converted radiation) to a plurality of different growth areas comprising the plurality of growth chambers 116 for growing photosynthetic material.

The solar radiation may be referred to as sunlight, solar irradiance, etc. The photosynthetic material, also referred to as "phototrophs" or "photoautotrophs", performs processes of biosequestration and photosynthesis. The photosynthetic material absorbs CO2 when growing based on the solar radiation and generates biomass. The photosynthetic growth system and or the photosynthetic growth apparatus may be referred to as including a "photobioreactor" (PBR). In some embodiments, the photosynthetic growth system 100 is used for growth of particular photosynthetic material that generate pharmaceutically useful by-products, such as generally modified algal species, e.g., micro-algae (or "microalgae).

The apparatus can improve the economics of microalgae growth by reducing the cost of photon delivery to the algae.

Photosynthetic Material

The photosynthetic material can include photosynthetic species having chlorophyll (e.g., green plants), plant species having phycobilins (e.g., red algae), photosynthetic bacteria (Cyanobacteria, also known as blue-green algae, blue-green bacteria or Cyanophyta) and microalgae. The microalgae include: Archaeplastida, Chlorophyta (Green algae), Rhodophyta (Red algae), Glaucophyta, Rhizaria, Excavata, Chlorarachniophytes, Euglenids, Chromista, Alveolata, Heterokonts, Cryptophyta, Dinoflagellates, and Haptophyta. The Heterokonts include Bacillariophyceae (Diatoms), Axodine, Bolidomonas, Eustigmatophyceae, Phaeophyceae (Brown algae), Chrysophyceae (Golden algae), Raphidophyceae, Synurophyceae, and Xanthophyceae (Yellow-green algae).

Preferred Radiation

Each type of photosynthetic material has a preferred photosynthesis absorption band of optical wavelengths for performing photosynthesis for which the process of photosynthesis is more performed more efficiently, i.e., less optical power is wasted as heat energy. The preferred photosynthesis absorption band is defined by specific species or characteristics of the photosynthetic material. Thus the at least one selected wavelength is selected to include one or more wavelengths respectively corresponding to one or more of the lowest photosynthetic absorption states of the photosynthetic material, thus providing a high photon efficiency for the photosynthesis.

The preferred radiation 108 is preferred as it includes wavelengths that are substantially utilised in photosynthesis by growing photosynthetic material, and therefore substantially (or wholly) stimulates photosynthesis and carbon dioxide capture, while also corresponding to the lower (or lowest) excited state(s) of the "photosystem" (e.g. , chlorophyll and/or accessory pigments). The colours (i.e., wavelengths) of the incident light on the photosynthetic material preferably match the absorption band which corresponds to the lowest excited state of the photosystem of the photosynthetic material. In the case of chlorophyll, absorption bands are present in the blue as well as in the red spectral regions. In terms of energy economy, the less energetic red photons which, on a per-quantum base, serve photosynthesis equally well as the energy richer blue photons, are preferred. Red light substantially corresponds to the photon energy needed to reach the first excited state of chlorophylls a and b, which are the pigments present in the light- harvesting-antenna complexes (LHC) of green algae. An electron present in the chlorophyll's first excited state contains enough potential energy to impart a trans- membrane charge separation at the photochemical reaction centre. From this intermediate status it may subsequently enter into the photosynthetic electron transfer chain. Blue light (blue photons contain about 40% more energy than red photons) can be absorbed by chlorophyll as well. With blue photons, electrons are elevated toward the second excited state of chlorophyll. However, this second excited state is just as effective for charge separation as the first excited one; in fact, the second excited state needs to relax to the first excited state before charge separation can occur. The excess energy present in the blue photons is wasted as heat. For example, microalgae can photosynthesise at their maximum rate when receiving only red light, which represents about 10% of the solar spectrum, rather than blue light which corresponds to a higher excited state.

The preferred radiation 108 represents portions of the spectrum of the solar radiation 104 selected to sustain the photosynthesis of the photosynthetic material, for.

In the described embodiment, the preferred radiation 108 includes a narrow band of the red spectrum of sunlight, representing about 10% of the incident solar power, that can sustain photosynthesis of plants such as microalgae. For example, the selected wavelengths can be in red light, from about 620 nm to about 780 nra, or from about 640 nm to about 750 nm, from about 660 nm to about 750 nm, for green algae.

In other embodiments, a low dose of blue light can be used to increase the rate of photosynthesis in certain algal species: the low dose of blue light (with wavelengths from about 455 nm to about 492 nm; or about 470 nm) can be from about 1% to about 20% of the total intensity. Blue light can play an essential role in regulation of cell growth and metabolism for certain photosynthetic materials, e.g., to promote growth and/or partition of nutrients within algae of certain species.

Heating and Power

As shown in Figure 1, the wavelength separator 106 separates from the solar radiation 104 two further components of radiation, namely heating radiation 130, which is directed to a heater 132 of the photosynthetic growth system 100, and photovoltaic (PV) radiation 134, which is directed to a photovoltaic (PV) cell 136. The heater 132 generates heat 138 based on the heating radiation 130, and the heat 138 can be directed to the plurality of growth chambers 116 to maintain a selected temperature of the photosynthetic material in the plurality of growth chambers 1 16, under control of a system controller to control the rate of photosynthesis and growth.

The PV cell 136 generates electrical power 140 from the PV radiation 134, and the electrical power 140 is stored in electrical storage 142, e.g., a battery or capacitive storage. The electrical power 140 in the electrical storage 142 is used by the lamp 126 to generate the artificial preferred radiation 128. As the electrical power 140 is stored in the electrical storage 142, the lamp 126 can generate the artificial preferred radiation 128 at some time after the PV cell 136 has received the PV radiation 134, for example, the lamp 126 may provide the artificial preferred radiation 128 during the night after the PV cell 136 has generated the electrical power 140 during a preceding day.

Wavelength Converter

The wavelength converter 112 generates additional photons in the preferred wavelength of the preferred radiation 108 based on photons in the non-preferred radiation 1 10 in a process referred to as "wavelength shifting". The wavelength converter emits growth light in the preferred photosynthesis absorption band based on photoluminescence, for absorption by the photosynthetic material, by absorbing solar radiation in a converter absorption band at least partially different from the preferred photosynthesis absorption band, e.g., using Stokes fluorescence.

The non-preferred radiation 110 includes a converter absorption band of wavelengths corresponding to a respective plurality of semiconductor quantum dots with absorption bands across this spectrum and emission spectrum between 640 nm and 750 nm (e.g., CdTe quantum dots), for the converter 112; and the heating radiation 130 and the PV radiation 134 includes a band of wavelengths, e.g., from about 750 nm to about 1000 nm for PV cells 136 and heater 132 configured to absorb over this band. The wavelength shifting in the wavelength converter 112 can be based on photoluminescent semiconductor quantum dots which absorb for example about 30% of the incident solar radiation 104 as the non-preferred radiation 110, and generate the preferred radiation 108 with an efficiency of for example about 30%, thereby providing an additional source of the preferred radiation 108. The quantum- dots in the wavelength converter 112 are in optical communication via their tunnel barriers with light pipes, which provide photon channelling towards the distributor 1 14. In the plurality of quantum dots, different sized quantum dots are selected to emit different preferred wavelengths (also referred to as differently "coloured" light) based on the energy spectra of the quantum dots. The energy spectra of the quantum dots are selected by controlling the geometrical size, shape, and the strength of the confinement potential. For example, the larger the dot, the more red (lower energy) its luminescence spectrum, which allows the quantum dot to absorb photons containing less energy, i.e., those closer to the red end of the spectrum, because electron-hole pairs in larger dots live longer causing larger dots to show a longer lifetime. Thus, the emitted growth light has an emission wavelength based on a morphology and dielectric environment of the QDs.

The quantum dots can be produced by chemical methods or by ion implantation, or using lithographic techniques with about 100 to 100,000 atoms within the quantum dot volume and diameters of 10 to 50 atoms. The quantum dots manufactured using a wet chemical process are fixed in a transparent material in the wavelength converter 112. The quantum dots may include CdSe. Alternatively, the quantum dots may be free of heavy metals with bright emissions in the visible far-red region of the spectrum with similar optical properties to CdSe quantum dots, for example, based on Indium phosphide (InP), an InGaP core coated with a ZnS lattice, copper, indium, gallium, selenium, Mn²⁺-doped ZnSe, and the organic semiconductor tetrabenzoporphyrin.

The quantum dots can be preferable to luminescent organic dyes in the wavelength converter 112 due to their improved brightness (owing to the high quantum yield) and stability (allowing much less photo destruction). Quantum dots can have broader absorption bandwidths to convert a broader range of non-preferred wavelengths to preferred wavelengths. An advantage of using a semiconductor-based wavelength converter, and in particular of using a converter including QDs, can be that the absorption wavelengths and emission wavelengths of the converter can be substantially controlled by selection of QD parameters such as morphology and surrounding environment. Furthermore, QDs can be more stable and less reactive than other wavelength converters, such as fluorescent dyes.

In some embodiments, alternative or additional photoluminescent materials are included in the wavelength converter 112, such as fluorescent monomers, fluorescent polymers, metal complex dopants and dyes, light-emitting dopants, and fluorescent dyes (from Sigma- Aldrich Co., 3050 Spruce St. St. Louis, MO 63103, USA), or phosphor materials.

The photoluminescent materials can include materials that convert non-visible parts of solar radiation, e.g., ultraviolet (UV) radiation (such as UVC with wavelengths from about 100 nm to 280 nm, UVB with wavelengths from about 280 nm to 315 nm, and UVA with wavelengths from about 315 nm to 400 nm) to radiation having the preferred wavelength(s).

Modulator

The modulator provides for intermittent exposure of a plurality of areas of the photosynthetic material to the preferred radiation 108 in a process referred to as "light flashing". The light flashing effect of the irradiation is applied to both the solar preferred radiation 108 and the artificial preferred radiation 128.

The light flashing can increase the growth rates of the photosynthetic material by reducing the incidence of photoinhibition. The term "photoinhibition" as used herein refers to any reduction in the quantum yield of photosynthesis, including saturation in the photosynthetic material causing a reduction in the photosynthesis in the photosynthetic material, and potentially damaging the photosynthetic material. Photoinhibition is reduced or avoided by only exposing the photosynthetic material to a limited number of photons, by limiting the time of exposure by the light flashing: by flashing the preferred radiation 108, each area of the photosynthetic material is exposed to the preferred radiation 108 for only a selected time for each flashing period. The flashing occurs at regular intervals, having a flashing frequency and a flashing duty cycle. The flashing frequency and flashing duty cycle are selected to provide sufficient light for photosynthetic growth while avoiding photoinhibition, and thus to stimulate a maximum level of photosynthesis. The kinetic resolution of time ranges at play in light trapping in the photosynthetic material are in the subpicosecond region, and charge separation proceeds in the subnanosecond domain. Even if light becomes trapped, its usage in charge separation can only occur if a reaction centre to which such an exciton is delivered is open (i.e., the primary electron acceptor involved in charge separation Q_A, is oxidized). The state of oxidation of Q_A is largely determined by the balance of the rates at which the photosynthetic electron flow from PS II reduces Q_A and the efflux toward PS I which oxidizes Q_A.. PS Il and PS I are functionally linked in series according to the Z-scheme of photosynthesis, which describes the electron transport chain used in photosynthesis. Electron flow via PS I also requires photons. In normal photosynthesis conditions, the PS I acceptor side does not restrain photosynthesis. If a PS Il reaction centre is closed for charge separation, the excited state of chlorophyll is relaxed via nonproductive heat release or fluorescence. Time-modulated photon delivery at a selected frequency (e.g., the flashing of the modulator) matches (or synchronised with) the light/dark rhythm in which most PS Il reaction centres would be open (oxidized) at the time of photon delivery. The photon flux density is selected to be no more than enough to saturate the maximum rate of growth. Trapped surplus light due to a photon flux density above saturation is preferably avoided to avoid unwanted heat, fluorescence and possible damage to the photosynthetic apparatus (also referred as "photoinhibition" or saturation).

The light modulator is controlled by a modulation controller to control the intensity at a selectable maximum intensity, minimum intensity, modulation frequency, and/or modulation duty cycle. For microalgae, the flashing frequency is selected to be between about 1 Hertz (Hz) to about 20 kilohertz (kHz), and the duty cycle is selected to have the preferred radiation 108 incident on the photosynthetic material for between about 8% or 10% to about 30% or 50% of each flashing period, or a ratio between about 1 :10 and about 1 :2 for on:off. For alternative photosynthetic material, the modulation frequency is between about 25 Hz to about 250 Hz. The flashing of an approximately constant photon flux across areas of the photosynthetic material, or across the plurality of growth chambers 116, may allow the photosynthetic material to grow at a rate matching, or better than, a rate of growth for the photosynthetic material exposed to the constant photon flux without flashing areas of the photosynthetic material. The number of photons required for photosynthesis can be reduced by the duty cycle relative to constant illumination without overall loss of growth, thus increasing the overall efficiency or rate of CO2 capture by photosynthesis.

Distributor

The modulator can be in the form of the distributor 1 14 for selectively distributing the solar radiation, the emitted growth light, and/or artificial light to a plurality of the one or more growth areas. The distributing provides a flash of solar radiation to each growth area, timed to substantially avoid, or at least reduce, photoinhibition, and/or sustained periods of dark that cause a substantial reduction of CO2 biosequestration, e.g., due to respiration of the photosynthetic material. In some embodiments, the distributor operates with a duty cycle of about 1 :10 (on:off) at a frequency of about 1 Hz to 20 kHz. The duty cycle can be selected to be between about 1 :2 and about 1 : 10 for microalgal species. The distributing action avoids waste of solar radiation through the use of multiple algae areas, in the chambers 116, that are exposed to the flashes of sunlight.

Artificial Radiation

As shown in Figure 1, the photosynthetic growth system 100 includes an artificial light source, in the form of a lamp 126. The artificial preferred radiation 128 is used to provide photo-stimulation to maintain photosynthesis in the photosynthetic material when the solar radiation 104 is insufficient to stimulate photosynthesis, e.g., at night. The lamp 126 is configured to generate artificial radiation having the at least one selected wavelength for irradiating the photosynthetic material to perform photosynthesis when the solar radiation is not available, to at least substantially reduce respiration by the photosynthetic material. The lamp 126 generates at least sufficient artificial preferred radiation 128 to substantially limit the onset of photorespiration by the photosynthetic material. "Photorespiration" (or "respiration") refers to the reverse of photosynthesis, where algae mass is lost and CO2 released. The lamp 126 can generate sufficient artificial preferred radiation 128 to stimulate photosynthesis at a level up to the substantial onset of photoinhibition. For microalgae, a constant low level illumination, with a photon flux in the range of about 9 to about 13 micro-mol per m² per second, can be sufficient to avoid photorespiration. When flashing artificial radiation, there is the potential to reduce the total energy required to avoid photorespiration by flashing the light at the above-mentioned intensity. The duty cycle can range from about 1.5:1 to about 10:1 depending on the microalgae species.

The artificial preferred radiation 128 is directed to the distributor 1 14. The artificial preferred radiation 128 includes the same preferred wavelengths as in the preferred radiation 108. The lamp 126 can include one or more light-emitting diodes (LEDs) generating the preferred wavelengths, e.g., in red light.

Manufacture

In a manufacturing process of the system 100, firstly the species or type of photosynthetic matter is selected, based on availability, photosynthetic rate, longevity, etc. The type of photosynthetic matter defines values of parameters in the optical system of the system 100, such as: the absorption band of wavelengths, and thus the materials and morphology of the quantum dots and the dielectric coatings required; the photoinhibition threshold, and e.g., the flashing frequency and duty cycle; and the photorespiration threshold, and thus the required flux of artificial light (which in turn determines electrical power requirements). The type of photosynthetic material and the optical system values determine the growth rate of the photosynthetic material, and thus values of parameters in the fluidic system of the system 100, including: gas (CO2) flow rate, nutrient (water) flow rate, and a growth rate of the photosynthetic material (including generating "biomass"), etc. Growth Areas

As shown in Figure 1 , the growth system 100 includes a nutrient source 118 for supplying input matter 120 to the one or more growth areas, in the plurality of growth chambers 116, to support the photosynthesis, and a drain 122 for draining output matter 124 from the plurality of growth chambers 116, for example grown plants and waste matter. The input matter 120 includes water, carbon dioxide and associated trace minerals including NaNO₃ K₂HPO₄, CaCl₂, C₆H₈O₇, C₆H₅₊4yFe_xN_yO₇, EDTA, ,Na₂CO_3, H₃BO₃ MnSO₄, ZnSO₄, CuSO₄,(NH₄)₆Mo₇O₂₄ to support the photosynthesis. In alternative embodiments, the input matter 120 includes brine. The output matter 124 includes oxygen gas and grown algae, (natural or genetically modified strains,) in the form of algae biomass, and may include hydrogen gas which is generated by some algae species in certain culturing conditions. The photosynthetic material is contained in a substantially sealed and closed processing system that avoids cross-contamination between the external environment and the photosynthetic material itself (e.g., due to environmental pollution leaking in, or biological material leaking out).

Each chamber 116 is substantially sealed to fluids, apart from the input and output ports. Each chamber 116 can be formed by a supported recyclable plastic container or bag. The recyclable container can be formed on-site under sterile conditions. The container can be single use, which eliminates the need for cleaning of the growth chamber 1 16, or can be multi-use, with the container being cleaned using toxic cleaning agents (e.g., a hydroxide) and agitation. The container can be made of a transparent (at least for the preferred radiation 108), cleanable and recyclable plastic material, such as polypropylene, polyethylene, or polycarbonate.

Each chamber 116 defines a light-penetration depth selected based on absorption of the light into the photosynthetic material (e.g., a transmission distance of about 75 mm or 100 mm) to avoid the self-shadowing (also referred to as "shading"), due to growth of the photosynthetic material (e.g. algal growth can limit the penetration of light into the algal material to a depth of about 75 mm to 100 mm). The chambers 1 16 may be arranged in an array, as described hereinafter. In some embodiments, the intensity, the period and the duty cycle of the modulation are also selected to substantially avoid self-shadowing of the photosynthetic material.

Tracking Collector and Guide System

As shown in Figure 2, a photosynthetic growth apparatus 200 of the photosynthetic growth system 100 includes the collector 102, in the form of a tracking collector 201, connected by a light guide, including delivery waveguide 202, to the distributor 1 14 which distributes the preferred radiation 108 to a plurality of light panels 204, which in turn spatially distribute the preferred radiation 108 to and across the plurality of growth chambers 1 16 respectively. In the tracking collector 201, the at least one reflective surface of the collector 102 is moveable to track movement of the sun.

The apparatus 200 includes a frame 206 for holding the tracking collector 201, the delivery waveguide 202, the distributor 1 14, the light panels 204 and the chambers 1 16 in their relative configuration. The frame 206 allows movement of the tracking collector 201 to follow the sun while supporting the chambers 116 when filled with fluid. The delivery waveguide 202 provides for substantial spatial separation of the tracking collector 201 and the growth chambers 116 to allow for the growing photosynthetic material to be generally separated from the solar radiation 104, to thereby allowing management of the environment of the photosynthetic material separate from external conditions. For example, the photosynthetic material is isolated in the growth chambers 116 from excessive heating by direct impingement of the solar radiation 104 and excess cooling due to radiation loss during the night or during cold weather.

The configuration of the photosynthetic growth apparatus 200 allows for the apparatus 200 to positioned with the tracking collector 201 on top of a roof, e.g., of a building or vehicle, and the growth chambers 1 16 positioned underneath the roof and therefore protected from the external environment. Furthermore, any heat generation associated with the wavelength converter 112 is generally separated from the growth chambers 116, allowing for better temperature control of the photosynthetic material. As shown in Figures 3 A and 3 B, in some embodiments the apparatus 200 includes an optical system 300 including the tracking collector 201, the delivery waveguide 202, the distributor 114 and the light panels 204. The tracking collector 201 includes a reflector 302 for reflecting the solar radiation 104 onto the light guide 1 13 in the form of waveguide beam 316 that directs light through the delivery waveguide 202 and the distributor 114 to a plurality of chamber waveguides 404 which guide the distributed light to the corresponding plurality of light panels 204.

The light panels 204 are shaped and oriented to fit on both sides of each chamber 116, substantially along the two extended faces of each chamber 1 16, for providing light into both sides of each chamber 116 substantially over the surface area of each chamber 116. The chambers 1 16 slidingly fit between the light panels 204 and the chambers 1 16 are substantially in contact with corresponding light panels 204 to provide substantial light conduction from each light panel 204 into its one or more corresponding chambers 116. A refractive-index matching material, such as a gel or thin film may lie between each light panel 204 and its corresponding chamber(s) 116 to improve light conduction from the light panels 204 to the chambers 116. The light panels 204 and chambers 116 are held in generally static contact by the frame 206.

As shown in Figure 3C, the tracking collector 201 includes the reflector 302 for receiving the solar radiation 104 and directing it to a first wavelength separator 304.

The reflector 302 is curved to act as a concentrator for focusing the solar radiation 104 into a small area of the first wavelength separator 304. The tracking collector 201 is mounted on a mechanical tracking system for tracking the reflector 302 to collect solar radiation 104 incident directly from the sun. Should the captured solar energy be so intense that photo inhibition of the algae is likely to occur, the tracking system is altered by a process management control system to reduce its photon capture efficiency, e.g., by turning the reflector 302 at least partially away from the sun. Waveguide Beam

The first wavelength separator 304 separates components of the solar radiation 104 into two groups: a first group, including the preferred radiation 108 and the non-preferred radiation 110, is directed into a first wave guide 306 of the tracking collector 201; a second group of components is directed to a heat and photovoltaic collector 308 of the tracking collector 201 which receives a heating radiation 130 and/or the PV radiation 134. The PV/heat collector 308 includes at least components of the heater 132 and the PV cell 136. As shown in Figure 3B, the PV/heat collector 308 includes a black-coloured pipe designed to absorb heat into fluid passing through the pipe, and being directed to a hot water storage system for example. The PV cell 136 includes a strip of photovoltaic devices for capturing the focussed, residual PV radiation 134. The photovoltaic devices are cooled by the fluid passing through the supporting structure of the PV/heat collector 308. The fluid may be a supply stream to the growth chamber 116 being partially diverted according to the particular photosynthetic material's temperature control requirements.

The first waveguide 306 directs the preferred radiation 108 and the non-preferred radiation 110 to a second waveguide separator 310 in the form of a dichroic coating on a surface of the first waveguide 306 that separates the preferred radiation 108 from the non-preferred radiation 110 by substantially reflecting the preferred radiation 108 back into the first waveguide 306 while transmitting the non-preferred radiation 110 into the wavelength converter 112. The wavelength converter 112 includes a material doped with semiconductor quantum dots that operate as photoluminescent compounds to transform at least a portion of the non-preferred radiation 1 10 into the preferred radiation 108. The non- preferred radiation 1 10 and any generated preferred radiation 108 propagates through the wavelength converter 1 12 to a second waveguide 312 and through the second waveguide 312 to a third wavelength separator 314 which reflects at least the preferred radiation 108 back to the first waveguide 306. The third wavelength separator 314 is a dichroic layer on the surface of the second waveguide 312. The generated preferred radiation 108 is reflected back through the second waveguide 312, back through the wavelength converter 112 and back through the second wavelength separator 310 to the first waveguide 306. The first waveguide 306 guides the preferred radiation 108 to the delivery waveguide 202 for use in photosynthesis. The first waveguide 306 includes secondary coatings and angled optical features to direct light along the first waveguide 306 in a direction transverse to the direction of the solar radiation 104. The non-preferred radiation 1 10 in the second waveguide 312 is either reflected by the third wavelength separator 314 back into the wavelength converter 1 12 for further conversion to further preferred radiation 108; alternatively, at least some wavelengths of the non-preferred radiation 1 10 are transmitted through the third wavelength separator 314 and out of the tracking collector 201. The dichroic coatings are specific to the wavelengths of the preferred photosynthesis absorption band, e.g., 640 nm to 750 nm for green algae.

The reflector 302 includes a curved metal sheet with a reflective coating on the inner curved surface. The reflector 302 may be of an elongate parabolic shape with an elongate focal line along the length of the tracking collector 201. The PV/heat collector 308, as shown in Figure 3C, has an approximately circular cross-section, and also extends the length of the tracking collector 201, as shown in Figures 3 A and 3B. The first wavelength separator 304 has a curved and elongated surface for receiving the solar radiation 104 and for focusing the heating radiation 130 and/or the PV radiation 134 onto the PV/heat collector 308.

As shown in Figure 3 C, the wavelength converter 112 may be in the waveguide beam 316, which also includes the first waveguide 306, the second waveguide 312 and the three wavelength separators 304, 310, 314. The waveguide beam 316 is an assembly of lateral waveguide components with coatings to manage light transmission through the surfaces. The coatings are thin films applied by vacuum sputtering onto polymer or glass substrates. The components are bonded together with optical adhesives such as used for camera lens manufacture. The waveguide beam 316 and the PV/heat collector 308 are supported along the length of the tracking collector 201 by support struts 303 connected to the reflector 302, as shown in Figures 3A and 3B. In some embodiments, the waveguide beam 316 is replaced by an alternative guide system 113 in the form of a waveguide assembly 1400, described hereinafter with reference to Figures 13 and 14.

Rotating Distributor

As shown in Figure 4, the distributor 114 receives light of the preferred radiation 108 from the collector 102 through the delivery waveguide 202. The delivery waveguide 202 is coupled to the collector 102 by a collector coupling 402 which is in optical communication with at least the first waveguide 306 and carries light from the collector 102 into the distributor 114.

The delivery waveguide 202 can be composed of a waveguide with an approximately circular cross-section, as shown in Figure 4, and may include a light pipe as manufactured by "3M" Corporation. The preferred radiation 108 is directed from the distributor 114 via a plurality of chamber waveguides 404 which guide the distributed preferred radiation 108 to the corresponding plurality of growth chambers 116. The chamber waveguides 404 have emitting faces 406 for emitting the distributed preferred radiation 108 to the plurality of growth chambers 1 16. The chamber waveguides 404 include polymer waveguides with an approximately rectangular cross-section and varying lengths selected to guide light to the corresponding plurality of light panels 204 and respective growth chambers 116, which are arranged to be generally mutually parallel, as shown in Figure 2.

As shown in Figure 5, the distributor 114 can be a moving distributor configured to selectively and sequentially direct the collected radiation and the converted radiation to the plurality of different portions of the photosynthetic material. The moving distributor is a rotating distributor including a rotating reflector. The rotating distributor includes a rotating switch mechanism for distributing the preferred radiation 108 to the chamber waveguides 404 including a rotating mirror mounted in alignment with the path of the preferred radiation 108. The switching device includes a switch 502 for switching the light using an angled mirror in the form of a solar reflector 504 that receives light from the delivery waveguide 202 and directs it into receiving faces 506 of the corresponding chamber waveguides 404. The receiving faces 506 of the chamber waveguides 404 are formed directly adjacent each other so as to form a substantially complete circle around the switch 502 to allow the incident preferred radiation 108 falling on the reflector 504 to be conducted into at least one of the chamber waveguides 404 at any rotational angle of the switch 502 (and thus any rotational angle of the solar reflector 504). The solar reflector 504 is supported at an angle on the switch 502 by a mechanical support 508. The switch 502 is rotationally mounted on a collar 510 which provides for the generally constant axial alignment of the solar reflector 504 at its various rotation angles, allowing for light to be directed from the delivery waveguide 202 into at least one of the chamber waveguides 404.

The switch 502 also directs light from the lamp 126 into the plurality of chamber waveguides 404 in a manner equivalent to the distribution of the solar preferred radiation 108 by having a further reflector on the underside of the solar reflector 504 (referred to as the lamp reflector 602, as shown in Figure 6) and oriented to direct the artificial preferred radiation 128 from the lamp 126 sequentially into at least one of the chamber waveguides 404 as the switch 502 rotates. The lamp 126 is housed in a lamp housing 512. The switch 502 is driven by an electric motor to rotate at a frequency selected to correspond to the flashing frequency described above. In some embodiments, the solar reflector 504 and the lamp reflector 602 in the switch 502 are replaced by surfaces that provide reflection through dielectric contrast, such as one or more prisms.

As shown in Figure 6, the solar reflector 504 directs the solar preferred radiation 108, following a solar light path 604 from the delivery waveguide 202 to the chamber waveguides 404 while using the same switch 502, the lamp reflector 602 reflects light from the lamp 126 along an artificial light path 606 from the lamp 126 to the plurality of chamber waveguides 404. The switch 502 can simultaneously supply solar preferred radiation 108 along the solar light path 604 and artificial preferred radiation 128 along the artificial light path 606 to different chamber waveguides 404, thereby allowing for a combination of artificial preferred radiation 128 and solar preferred radiation 108 to be combined by the distributor 114 at the flashing frequency. This may allow for artificial preferred radiation 128 generated at a low power to provide a photon flux to contribute to the solar preferred radiation 108 when the solar preferred radiation 108 is insufficient for the desired level of photosynthesis but the solar radiation 104 is still available, e.g., at dawn and dusk.

As shown in Figure 7 A, the optical system 300 substantially conducts the preferred radiation 108 from the distributor 114 to the photosynthetic matter by guiding light from the emitting faces 406 of the chamber waveguides 404 into receiving faces 708 of the plurality of light panels 204, and along the light panels 204 on a corresponding plurality of input radiation paths 710. The receiving faces 708 are configured to fit closely with the emitting faces 406 of the chamber waveguides 404 to allow for a substantial fraction of the light in the chamber waveguides 404 to be conducted into the growth chambers 116. The light panels 204 also include scattering mechanisms, such as angled reflectors, to scatter the input light in towards the areas between the light panels 204 where the chambers 116 are received. The light panels 204 are manufactured of a polymer material that is substantially transparent at least to the preferred absorption wavelengths. The reflecting surfaces in the transparent walls 706 are embossed into the surface of the transparent walls 706.

Switching Distributor

In the described embodiment, a rotating switching device is used in the distributor 114 to direct the preferred radiation 108 to the plurality of growth chambers 116. In some alternative embodiments, the moving distributor can be a switching distributor including a plurality of switching reflectors. The distributor 1 14 can include an alternative switching device including a plurality of switching reflectors. In some embodiments, the switching reflectors rely on total internal reflection effects and liquid crystal switching, as described in a journal paper by A. Zhang, K. T. Chan, M. S. Demokan, V. W. C. Chan, P. C. H. Chan, H. S. Kwok and A. H. P. Chan, entitled "Integrated liquid crystal optical switch based on total internal reflection" (published in Applied Physics Letters, 86, 211 108, 1-3, 2005). In other alternative embodiments, the switching reflectors may be based on switching techniques associated with the optical communications industry such as modular micro-electromechanical system (MEMS) switches, as described in a journal paper by A. Fernandez, B. P. Staker, W. E. Owens, P. Lawrence, L. P. Muray, P. James, J. P. Spallas and W. C. Banyai, entitled "Modular MEMS Design and Fabrication for an 80 x 80 Transparent Optical Cross-Connect Switch" (published in Optomechatronic Micro/Nano Components, Devices, and Systems, Ed. Yoshitada Katagiri, Proc. SPIE, Vol. 5604, 208- 217, 2004).

As shown in Figure 7B, in some embodiments, the distributor 114 includes switching reflectors including MEMS switches in a MEMS distributor 720 which includes a plurality of MEMS mirrors 722 A, 722B, 722C, etc. The distributor 114 includes a combiner 724 which combines the preferred radiation 108 from the wavelength separator 106 and the wavelength converter 112 and the artificial preferred radiation 128 from the lamp 126 and directs the combined light into the MEMS distributor 720 where it falls on a primary mirror 722E in the centre of the MEMS distributor 720. The primary mirror 722E is switched, by a control system, to direct the combined light to one of a plurality of further mirrors, in the first case being either the secondary mirror 722D or the secondary mirror 722F. Both secondary mirrors 722D and 722F are also active reflectors and these secondary mirrors 722D, 722F are controlled to direct the light to: either the receiving face 708 of corresponding light panels 204 optically coupled to the MEMS distributor 720, as shown in Figure 7B by a broken arrow; or one of a plurality of reflective surfaces 726 in the MEMS distributor 720, as shown in Figure 7B by a solid arrow. The reflective surfaces 726 in turn further direct the light to tertiary MEMS mirrors 722C or 722G. As with the secondary mirrors 722D, 722F, the tertiary mirrors 722C, 722G are controlled to direct light to either their corresponding light panels 224 (shown by the broken arrows) or to further mirrors 726 of the main distributor 720 (shown by the solid arrows), and to quaternary MEMS reflectors 722B, 722H, etc. Through electronic control of the MEMS mirrors 722A, 722B, 722C etc., the main distributor 720 sequentially switches the preferred radiation 108 into the plurality of light panels 204, via corresponding receiving faces 708, and thus into the respective growth chambers 1 16, in a similar manner to the switch 502 described above with reference to Figure 5. Example Growth Chambers

Each growth chamber 116 is configured to allow fluid flow to and from the photosynthetic material to provide nutrients etc. to allow it to perform photosynthesis and grow. As shown in Figure 8, each chamber 116 is generally rectangular in cross-section and elongate in a mutually parallel direction to provide for a large volume while having closely spaced parallel walls. Each chamber 116 is configured to receive the preferred radiation 108 from the light panels 204 along two sides of each chamber 116 through substantially mutually parallel transparent side walls 706, thereby providing the photosynthetic material with the preferred radiation 108 from two directions. As each chamber 116 is generally flat and rectangular, having a width of about 75 mm to 150 mm between the side walls 706 — and the preferred radiation 108 is generally incident from both sides of the width — the photosynthetic material in the chamber 116 is generally no more than half the width of the chamber 116 distant from an input of light to the chamber 1 16. By providing light from both sides of the chamber 116, the photosynthetic growth apparatus 200 allows for twice the thickness of the chamber 116 while substantially avoiding self-shadowing of the light, and a consequent reduction in photosynthesis, by growing of the photosynthetic material.

As shown in Figure 8, the chamber 1 16 includes an inlet pipe 802 along two edges of the chamber 1 16 for providing a flow of gas and/or fluid into the chamber 116 via a plurality of perforations 806 or holes (which act as sparging features) between the inlet pipe 802 and the body of the chamber 116, which is defined by the sidewalls 706. The perforations 806 allow sparging, which is the process of bubbling a gas (e.g.,CO2) through a liquid {e.g., the grown medium of the photosynthetic material), between the inlet pipe 802 and the body, which form two separate compartments of the chamber 1 16. The chamber 116 includes an outlet 804 at a corner of the chamber 1 16 to provide an outlet for fluid, gas and/or the photosynthetic matter.

The chamber 116 can be a replaceable container, formed of a material such as polyethylene with a higher transmit ability for selected wavelengths (e.g., red light for photosynthetic green microalgae). The chamber 1 16 is constructed by welding sheets of material and blowing to form the inlet pipe 802, the outlet 804 and the body between the sidewalls 706 to be substantially sealed except for the perforations 806 between the inlet pipe 802 and the body. The sparging features are formed integrally as part of each chamber 1 16. The integrated forming of the sparging features in each two-compartment chamber 116 can be advantageous in efficient manufacture and operation of each chamber 1 16.

Array

As shown in Figure 9, a growth array 900 includes a plurality of chambers 116 arranged to be mutually parallel, to allow the light panels 204 to fit between adjacent chambers 116 and to be supported in the frame 206 of the apparatus 200. The inlet pipes 802 of the chambers 116 are joined by a gas inlet manifold 902 which provides inlet gas to the inlet pipe 802 and by a fluid inlet manifold 904 which provides fluid inlet to the inlet pipe 802. The outlets 804 of each chamber 116 are connected by an outlet manifold 906 for receiving fluids, gases and material from the chambers 116. The array 900 is arranged and held in the frame 206 in an upright configuration with reference to Figure 9, such that the fluid level in the plurality of chambers 116 is controlled by overflow into the output manifold 906, which is referred to as a "weir configuration". The chambers 116 are substantially sealed apart from the inlet pipe 802 and the outlet 804, thereby providing for control of environmental contamination e.g., from external photosynthetic matter, fluids and/or gases.

As shown in Figure 10, the frame 206 includes a base 1002 for supporting the light panels 204 and the chambers 1 16 in their mutual configuration, and stands 1004 for supporting the collector 102 to move for controlling the quantity of incident sunlight to the collector 102, while being fixed relative to the distributor 114, e.g., by allowing rotation of a collector 102 in the stands 1004 while fixing the delivery waveguide 202 along the axis of rotation of the collector 102 (as shown in Figure 2). The frame 206 is configured to support the configuration of the chambers 116 and optical system 300 by resisting forces due to the weight of fluid in the chambers 116 and flow of fluid through the chambers 116.

Facility

As shown in Figure 11 , a plurality of growth apparatuses 200 are combined to form a photosynthetic growth facility 1100, arranged in an array to collect incident radiation and to allow for fluidic control of the contents of the chambers 1 16 via the inlet and outlet manifolds 902, 904, 906.

The facility 1100 can include the array of solar collectors 102 forming a roof, which is substantially sealed to fluid and/or temperature. The facility 1100 can thus be substantially sealed to provide a contained or "functionally closed" environment to protect and contain the photoluminescent material, which may be genetically modified plants/algae that need to be kept in a closed system.

Fluidic System

As shown in Figure 12, a fluidic processing system 1200 provides a generally closed system. The growth chambers 1 16 are linked to a water supply 1202 and a sparge gas supply 1204 which supply the input matter 120. "Sparge gas" refers to gas for sparging in the photosynthetic growth system 100, such as CO2 and flue gas. The output matter 124, including the photosynthetic material, is diluted out of the growth chamber 116 via the outlet 804, and delivered with a fluid stream to a separator 1206 where the photosynthetic material is concentrated, and delivered to a biomass collection 1208, while clarified water is returned to a water recycle tank 1210 in a water recirculation circuit. The water supply 1202 includes a pump 1212 for controlling the pressure and flow rate of water into the inlet pipe 802 of each chamber 116. The sparge gas supply 1204 includes a blower 1214 for receiving flue gas, e.g., from an industrial CO₂ generator, and for controlling the pressure and flow rate of the sparge gas into a gas inlet pipe 1216 of the inlet pipe 802. Sparge gas stripped of its CO2 in the bioreactor, and augmented with oxygen and/or hydrogen released by the photosynthetic process in the growth chambers 116, flows through the chamber 116 and out through the outlet 804 where it is collected by a vent 1218 and may be recirculated into the sparge gas supply 1204.

The water supply 1202, supplemented where necessary with trace minerals, and the sparge gas supply 1204 comprise the "nutrient source" 1 18. The vent 1218 and the separator 1206 comprise the "drain" 122. In the described embodiment, the C02 is directed with the sparge gas into the chamber 116 by the gas inlet pipe 1216. In alternative embodiments, the C02 may be delivered to the chamber pre-absorbed into the fluid pumped by the water supply 1202 into the inlet pipe 802.

Water flow rates in the fluidic system 1200 are controlled to manage a concentration of photosynthetic material in the chamber 116 close to a maximum level limited by the self- shadowing effect. During periods of low light availability, such as in winter or at night, the photosynthetic material concentration may be reduced through control of the water supply 1202 to minimise the amount of artificial radiation 128 required to avoid respiration.

The fluids in the closed water recirculation circuit 1202 are monitored for pH and temperature, and compensation for pH and temperature change is introduced if required. For example, controlling the CO2 concentration is used for managing pH, particularly with brine water. A brine-based system allows CO2 to be directly delivered with the water supply 1202.

An electronic control system 1220 controls the rates of liquid and gas flow in the fluidic system 1200 by controlling the pump 1212, the blower 1214, etc. The control system 1220 uses electronic signals received from sensors, e.g., representing gas partial pressures and biomass weights, together with preset operating parameters (e.g., temperature etc., associated with the growth system 100) to control the fluidic system 1200, and aspects of the growth system {e.g., properties of light incident on the photosynthetic material).

Alternative Light Guide System

In some embodiments, the light guide 113 is in the form of the waveguide assembly 1400 including a plurality of guide elements 1300, as shown in Figures 13 and 14. The wave guide assembly 1400 operates to receive concentrated photons of light from the collector 102 and guide them to the distributor 114. The waveguide assembly 1400 includes elements of the wavelength converter 1 12 in the form of photoluminescent material in the waveguide assembly 1400, as described hereinafter. The guide element 1300 includes a curved main reflective surface 1306 (or face), as shown in cross-section in Figure 13, which reflects light incident on the guide element 1300 from an input direction 1302 having an effective input cross-section 1304 as shown in Figure 13, and partially focuses or concentrates the light into a region having an output direction 1308 and effective output cross-section 1310. The main surface 1306 is formed such that the output direction 1308 for a substantial majority of input light rays that is generally perpendicular to the input direction 1302. Thus the guide element 1300 guides lights coming from the input direction 1302, or at least generally falling into the guide element 1300 through its input face 1312, through an output face 1316 of the guide element 1300 in the output direction 1308, which is generally perpendicular to the input direction 1302. The main surface can include a compound parabolic concentrator (CPC) shape, e.g., as described in the document "Modelling of 3D-CPCs for Concentrating Photovoltaic Systems", by A. Parretta, P. Morvillo, C. Privato, G. Martinelli and R. Winston (from the "PV in Europe from PV Technology to Energy Solutions" Conference and Exhibition, at the Palazzo dei Congressi in Rome, Italy, from 7 to 11 October 2002). For some input directions 1302, the input rays may fall incident upon a secondary curved reflective surface 1314 (or face) of the guide element 1300, which lies opposed main surface 1306, and together with the main surface 1306 defines the input face 1312 and a narrow end of the reflector element 1300. The secondary surface 1314 is reflective as the main surface 1306, and directs input light to the main surface 1306, whence the light is directed to the output face 1316 in the output direction 1308 at the narrow end of the element 1300. The main surface 1306 thus directs the collected radiation behind the secondary surface 1314.

The guide element 1300 can accept light from a plurality of different input direction 1302 and direct light from each direction to the output face 1316 in at least generally the output direction 1308. The guide element 1300 can therefore concentrate solar radiation incident in the input direction 1302 as the sun moves relative to the guide element 1300 during the day and/or during the year. The inner surfaces of the main surface 1306 and the secondary surface 1314 are coated with broad-spectrum optically reflective materials. The waveguide assembly 1400 includes a plurality of reflective guide elements 1404, each formed according to the guide element 1300, arranged on one side of the waveguide assembly 1400, as shown in Figure 14, to receive light falling on an input surface 1402 of the waveguide assembly 1400 and to direct it along the waveguide assembly 1400 into a main output direction 1408. The main output direction 1408 is longitudinally along the waveguide 1400. The plurality of reflective guide elements 1404 are aligned in an array along the input surface 1402, as shown in Figure 14, with their input faces aligned in the same direction and their output directions aligned in generally the same direction, towards the main output direction 1408. The reflective guide elements 1404 include transparent bodies 1406 (e.g., glass) which allow transmission of the input radiation. Light is transmitted from the reflective guide elements 1404 into a main guide 1410 of the waveguide assembly 1400 which is transparent to conduct the light (e.g., being air-filled).

The waveguide assembly 1400 includes a plurality of dichroic guide elements 1412 aligned in an array in the waveguide assembly 1400 on the opposed side of the main guide 1410 from the reflective guide elements 1404. The dichroic guide elements 1412 are shaped each with a dichroic surface similar to the main surface 1306 of the guide element 1300. The dichroic surface is coated (e.g., by sputtering) with layers and/or structures to reflect light of the preferred radiation 108 and to transmit light of the non-preferred radiation 110, at least for light incident on the main surfaces of the dichroic guide elements 1412 in the main output direction 1408 (i.e. light coming from and guided by the reflective guide elements 1404). The dichroic guide elements 1412 are arranged to direct preferred radiation 108 along the main output direction 1408 and to receive non-preferred radiation 1 10 into the body, i.e., the photoluminescent bodies 1414 as shown in Figure 14 of the dichroic guide elements 1412. The dichroic guide elements 1412 include photoluminescent material in the photoluminescent bodies 1414 which acts as the wavelength converter 1124 for converting a substantial portion of non-preferred radiation 110 to preferred radiation 108. Non-preferred radiation 110 entering the photoluminescent bodies 1414 is at least partially converted into the preferred radiation 108. The dichroic guide elements 1412 reflect converted radiation from the photoluminescent bodies 1414 into waveguide assembly 1400 in the main output direction 1408. The dichroic guide elements 1412 are arranged with output faces directed in the same direction as the output faces of the reflective guide elements 1404, thus guiding the preferred radiation 108 in the main output direction 1408. The dichroic guide elements 1412 include primary dichroic surfaces 1418 for receiving the non-preferred radiation 110 into the photoluminescent bodies 1414 and for reflecting the preferred radiation 108, as shown in Figure 14. The primary dichroic surfaces 1418 are shaped as the main surface 1306 of the guide element 1300. The dichroic guide elements 1412 include secondary dichroic surfaces 1420 which reflect preferred radiation 108 that is generated in the photoluminescent bodies 1414 back into the photoluminescent bodies 1414 and thus through the output faces of the dichroic guide elements 1412, and thus into the main guide 1410 in the main output direction 1408. The secondary dichroic surfaces 1420 allow transmission of the non-preferred radiation 110, which is not converted by the photoluminescent material in the photoluminescent bodies 1414, and thus is transmitted by the secondary dichroic surfaces 1420 through a non- preferred output interface 1416 of the waveguide assembly 1400. The non-preferred output interface 1416 is on an opposed side of the waveguide assembly 1400 to the input surface 1402: thus, solar radiation incident on the input surface 1402 is collected by the reflective guide elements 1404 and directed along the main output direction 1408. Preferred radiation 108 in the guided light in the main guide 1410 is reflected by the reflective guide elements 1404 and dichroic guide elements 1412 which form the sides of the main guide 1410. Non- preferred radiation 110 in the guided solar radiation is transmitted by the dichroic guide elements 1412 into the photoluminescent bodies 1414 which at least partially convert the non-preferred radiation 110 into preferred radiation 108, which is then reflected back into the main guide 1410 for transmission in the main output direction 1408. The main output direction 1408 is defined by the common alignment of the output faces of the reflective guide elements 1404 and the dichroic guide elements 1412.

Light guided by one of the reflective guide elements 1404 into the main guide 1410 can follow one of a plurality of paths in the waveguide assembly 1400, depending on its wavelength. For example, light can follow path "A", as shown in Figure 14, which passes through the uncoated external face of the input surface 1402 into one of the reflective guide elements 1404, and is reflected by the main surface of the reflective guide element 1404 into the main guide 1410 in the main output direction 1408. As the light on path A does not lie exactly in the main output direction 1408, it reaches the side of the main guide 1410 opposite the reflective guide elements 1404 and is reflected by the dichroic guide element 1412 since it is of the preferred wavelength. Light of the non-preferred wavelength can follow along a path "B", which is directed in the same way as the preferred wavelengths by the reflective guide elements 1404, but is transmitted into one of the photoluminescent bodies 1414 by a corresponding one of the dichroic guide elements 1412 which has a dichroic coating. The at least one photon on path B is converted into a photon of the preferred wavelength, and is reflected by internal dichroic coatings on the secondary dichroic surfaces 1420 into the main guide 1410, as shown in Figure 14. A solar light ray following path "C" of the non-preferred wavelength is transmitted by the primary dichroic surface 1418 of one of the dichroic guide elements 1412, and is not converted by the photoluminescent bodies 1414 and therefore remains at the non-preferred wavelength, and is therefore transmitted by the secondary dichroic surface 1412 out of the non-preferred output interface 1416 of the waveguide assembly 1400.

Light transmitted from the non-preferred output interface 1416 is used for generating heat and/or generating electricity from photovoltaic cells as described hereinbefore.

The waveguide assembly 1400 can be formed from a plurality of the transparent bodies 1406, formed in the geometry of the guide element 1300, coated in reflective materials on the main surface and a secondary surface, and arranged in an array having the same orientation, as shown in Figure 14. The photoluminescent bodies 1414 are formed of material that exhibits Stokes fluorescence, e.g., a transparent material incorporating a Stokes fluorescent material, such as quantum dots in a transparent substrate. The photoluminescent bodies 1414 (also referred to as "Stokes fluorescent bodies" in some embodiments) are coated with dichroic surfaces, arranged to reflect the preferred radiation 108 and transmit the non-preferred radiation 110 into the photoluminescent bodies 1414 through the main surface 1306 and out of the photoluminescent bodies 1414 through the secondary dichroic surfaces 1420. The dichroic guide elements 1412 are arranged in an array having the same orientation along the non-preferred output interface 1416. The main guide 1410 can be formed as a cavity between the reflective guide elements 1404 and the dichroic guide elements 1412. The reflective guide elements 1404 and the dichroic guide elements 1412 can be polished cast glass components, coated using sputter coating, and assembled into the waveguide assembly and held in a generally fixed geometrical relationship by an external frame or holder. Other transparent materials and coatings can be used that can withstand the heat generated in the waveguide assembly 1400 during use.

Tilting-Arm Collector

In some embodiments, the collector 102 can be in the form of a tilting-arm collector 1500, which includes a fixed, or non-moving reflector 1502 and a moving light guide 1504 for receiving solar radiation from the sun via the reflector 1502, as shown in Figure 15. The at least one reflective surface of the tilting-arm collector 1500 is fixed relative to movement of the sun. The moving light guide 1504 is a form of tilting arm receiver (or radiation capture device) moveable (or configured to move) to track movement of the concentrated solar radiation caused by movement of the sun.

The reflector 1502 is generally fixed in relation to the Earth, and the light guide 1504 is moved by a motor and controller to track the approximate focus or concentration area of the reflector 1502 as the sun moves relative to the reflector 1502. The reflector 1502 is a longitudinal trough reflector, which gathers light to a linear area by reflecting above the surface of the reflector 1502. The light guide 1504 is held by a tilting arm 1508 and support arm 1510 above the reflector 1502 and is tilted by the control system to the position above the reflector 1502 where the solar light is being concentrated. The light guide 1504 receives solar radiation from the reflector 1502, and directs it, e.g., using the waveguide assembly 1400, to a delivery waveguide 1506, which delivers the light to the distributor 114.

The light guide 1504 is positioned by the control system at a height and angle above the reflector 1502 to collect the majority of reflected rays, thus collecting a plurality of incident rays 1706 as collected rays 1704, as shown as for a plurality of positions of the sun and the light guide 1504 in Figures 17A to 17E. As shown in Figures 17A to 17E, a substantial portion of the incident rays 1706 are collected by the light guide 1504, for a substantial plurality of positions of the light guide 1504. As the light guide 1504 itself has a surface area much smaller than the surface area of the reflector 1502, it does not substantially obscure or block the incident rays 1706 from falling on the reflector 1502, or from falling on an adjacent reflector in an array of the reflectors 1502. Preliminary experimental results indicate that an array of tilting-arm collectors 1500 can have substantially the same efficiency of solar collection as an array of the tracking collectors 201, e.g., an example tilting-arm collector efficiency 1708, for capturing solar radiation, is similar to a tracking mirror collector efficiency 1710 over a full 180-degree range of angles of the sun relative to the horizon, as shown in Figure 17F.

A tilting-arm collector array 1600, as shown in Figure 16, is formed of a plurality of tilting-arm collectors 1500, and the plurality of reflectors 1502 form a reflector array 1602. The collector array 1602 captures a substantial portion of all instant radiation on the tilting- arm collector array 1600, thus forming a high-efficiency solar collector array. The tilting- arm collector array 1600 can also form a roof, as the reflectors 1502 do not move.

An example non-moving reflector 1502 can have parabolic shape with a width of about 1200 mm and conform to the parabolic shape defined by Y = 0.0004 X². The tilting arm 1508 can be about 650 mm long with a pivot point about 100 mm below the bottom of the parabolic surface. The width of the light guide 1504 can be about 200 mm, which is sufficiently wide to gather a substantial amount of the reflected solar radiation, while being sufficiently narrow to avoid substantial shadowing of the reflector 1502 and/or an adjacent reflector 1502.

Having the reflector array 1602 form a roof can be advantageous as the roof can be substantially sealed against environmental influences, such as external temperature fluctuations, wind, dust etc. , and against contamination of the external environment by materials in a growth chamber array 1604 beneath the reflector array 1602, such as genetically modified algae forms. Genetically formed algae may be a preferable photosynthetic material, but may need containment in a facility for environmental safety reasons, etc. The reflector array 1602 may also be manufactured and installed relatively simply and cheaply.

Concentrating Collector

The collector 102 may be in the form of an concentrating collector 1800 with at two reflective surfaces: a primary face 1802 forming a first surface, and a secondary face 1808 forming a second surface.

The primary face 1802 receives incident solar rays 1804 and gathering and reflecting them into collected rays 1806 in a narrowing part of the concentrating collector 1800, which has a wide input aperture for the incident rays 1804 defined by the primary face 1802 and the secondary face 1808, and a narrow region for the collected rays 1806 defined by the primary face 1802 and the secondary face 1808 drawing closer together. The collected rays 1806 pass through a gap between the narrow ends of the primary face 1802 and the secondary face 1808, and effectively enter behind the secondary face 1808. The secondary face 1808 is generally shorter than the primary face 1802. The primary face 1802 can have a compound parabolic concentrator (CPC) shape.

A concentrating collector array 1900 can be provided by a plurality of concentrating collectors 1800 formed as longitudinal troughs, which are mutually parallel as shown in Figures 19A, 19B and 19C. Each concentrating collector 1800 has a generally parabolic concentrator geometry and can be locked into an adjacent concentrating collector 1800 to form a fixed industrial roofing structure or decking. The concentrating collector array 1900 is assembled using a plurality of curved reflective sheets forming the primary face 1802 or the secondary face 1808 of the concentrating collectors 1800, each sheet being supported by a plurality of support struts 1902 which conform to the geometry of the concentrating collector 1800, the support struts 1902 being supported on a plurality of support beams 1904 which form the roof and run perpendicular to the troughs of the concentrating collector array 1900, as shown in Figure 19B. The support beams 1904 can be commercially available steel support structures, and the support struts 1902 can be formed of steel or aluminium for connection to the support beams 1904. The reflective material for the faces of the concentrating collector 1800 can be formed of coated shaped plastic or metal sheets for gathering the solar radiation. The troughs 1908 in the narrow bend of the primary face 1802, as shown in Figure 19C, are configured for receiving water run-off such as rain incident on the concentrating collector array 1900.

The concentrating collector array 1900 includes a plurality of light guides 1906, such as guides 1 13 as described hereinbefore, for receiving the collected rays 1806 of each concentrating collector 1800. The at least one reflective surface of each primary face 1802 concentrates the solar radiation to each light guide 1906, which forms a the receiver (or radiation capture device) substantially protected from environmental and mechanical damage. The light guide 1906 is protected from physical or environmental damage, e.g., due to rain or storms, by being protected under the secondary face 1808 of each concentrating collector.

In an example configuration, the concentrating collector array 1900 has the concentrating collectors 1800 forming troughs oriented in an east-west direction. The concentrating collector array 1900 can be suspended as a roof over a plurality of growth chambers 116 as shown in Figure 19D to form a concentrating collector facility 1912. The facility 1912 includes a plurality of distributors 114 with light guided from the concentrating collectors 1800 through a plurality of light guides 1906. The light from the light guides 1906 may be combined in a plurality of combiners 1910 in the guide 113 for guiding light to the plurality of distributors 1 14. The growth chambers 1 16 are supported in the facility 1912 as described hereinbefore.

Interpretation

Many modifications will be apparent to those skilled in the art without departing from the scope of the present invention as hereinbefore described with reference to the accompanying drawings.

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

CROSS REFERENCE TO RELATED APPLICATIONS

The disclosure of US Provisional Application No. 61/180240, filed 21 May 2009, is hereby incorporated by cross reference.

REFERENCE SIGNS LIST

Claims

CLAIMS:

1. A photosynthetic growth apparatus including: at least one solar collector configured to collect solar radiation; at least one growth area configured for photosynthetic material to perform photosynthesis using radiation having at least one selected wavelength; a wavelength converter configured to convert at least a portion of the collected solar radiation having at least one wavelength different from the at least one selected wavelength to radiation with the at least one selected wavelength for the photosynthetic material; and a light modulator configured to control irradiation of the photosynthetic material by the radiation with the at least one selected wavelength to at least substantially reduce photoinhibition of the photosynthesis.

2. The photosynthetic growth apparatus of claim 1, wherein the irradiation of the photosynthetic material uses light arising from the solar radiation.

3. The photosynthetic growth apparatus of any one of claims 1-2, wherein the light modulator modulates the amplitude of the irradiation of the photosynthetic material.

4. The photosynthetic growth apparatus of claim 3, wherein the light modulator modulates the amplitude of the irradiation between zero and a maximum.

5. The photosynthetic growth apparatus of any one of claims 1—4, wherein the light modulator includes a distributor configured to distribute the collected radiation and the converted radiation between a plurality of different portions of the photosynthetic material in the at least one growth area.

6. The photosynthetic growth apparatus of claim 5, wherein the distributor includes a moving distributor configured to selectively and sequentially direct the collected radiation and the converted radiation to the plurality of different portions of the photosynthetic material.

7. The photosynthetic growth apparatus of claim 6, wherein the moving distributor is a rotating distributor including a rotating reflector.

8. The photosynthetic growth apparatus of claim 6, wherein the moving distributor is a switching distributor including a plurality of switching reflectors.

9. The photosynthetic growth apparatus of any one of claims 5-8, wherein the plurality of different portions of the photosynthetic material are in respective different growth areas of the at least one growth area.

10. The photosynthetic growth apparatus of any one of claims 1-9, wherein the light modulator is controlled by a modulation controller to control the intensity at a selectable maximum intensity, minimum intensity, modulation frequency, and/or modulation duty cycle.

11. The photosynthetic growth apparatus of claim 10, wherein the modulation frequency is about 1 Hz to 20 kHz, or about 25 Hz to 250 Hz.

12. The photosynthetic growth apparatus of any one of claims 10 and 1 1, wherein the duty cycle is between about 10% and about 50%.

13. The photosynthetic growth apparatus of any one of claims 1-12, wherein the light modulator is controlled by a modulation controller to control the intensity to at least substantially reduce self-shadowing of the photosynthetic material.

14. The photosynthetic growth apparatus of any one of claims 1-13, wherein the at least one solar collector includes at least one reflective surface for concentrating the solar radiation.

15. The photosynthetic growth apparatus of claim 14, wherein the at least one reflective surface is moveable to track movement of the sun.

16. The photosynthetic growth apparatus of claim 14, wherein the at least one reflective surface is fixed relative to movement of the sun, and the at least one solar collector includes at least one respective tilting arm receiver moveable to track movement of the concentrated solar radiation caused by movement of the sun.

17. The photosynthetic growth apparatus of claim 14, wherein the at least one solar collector forms a fixed roofing structure, and wherein the at least one reflective surface concentrates the solar radiation to a receiver substantially protected from environmental and mechanical damage.

18. The photosynthetic growth apparatus of claim 17, wherein the at least one reflective surface includes two surfaces, and the first surface is shaped to concentrate the solar radiation to the receiver behind the second surface.

19. The photosynthetic growth apparatus of claim 18, wherein the first surface has a compound parabolic concentrator shape.

20. The photosynthetic growth apparatus of any one of claims 1-19, wherein the at least one selected wavelength includes one or more wavelengths respectively corresponding to one or more of the lowest photosynthetic absorption states of the photosynthetic material.

21. The photosynthetic growth apparatus of claim 20, wherein the at least one selected wavelength includes one or more wavelengths corresponding to red light.

22. The photosynthetic growth apparatus of claim 21, wherein the red light includes wavelengths from about 620 run to about 780 nm.

23. The photosynthetic growth apparatus of claim 22, wherein the red light includes wavelengths from about 660 nm to about 750 nm.

24. The photosynthetic growth apparatus of any one of claims 1-23, including an artificial light source configured to generate artificial radiation having at least one selected wavelength for irradiating the photosynthetic material to perform photosynthesis when the solar radiation is not available, to at least substantially reduce respiration by the photosynthetic material.

25. The photosynthetic growth apparatus of claim 24, wherein the artificial light source includes light-emitting diodes (LEDs) emitting red light.

26. The photosynthetic growth apparatus of any one of claims 24 and 25, wherein the artificial light source is powered by electricity generated photovoltaicly from portions of the solar radiation not including the at least one selected wavelength.

27. The photosynthetic growth apparatus of any one of claims 1-26, including a light guide configured to receive and guide the collected radiation and the converted radiation from the solar collector to the photosynthetic material.

28. The photosynthetic growth apparatus of claim 27, wherein the light guide includes a plurality of reflector elements for receiving the collected radiation from a first direction and for directing the received radiation in a second direction generally perpendicular to the first direction.

29. The photosynthetic growth apparatus of claim 28, wherein each reflector element includes two curved reflective faces with an open end for receiving the collected radiation, wherein a first curved reflective face is shaped to direct radiation behind a second curved reflective face at a narrow end of the reflector element.

30. The photosynthetic growth apparatus of any one of claims 27-29, wherein the light guide includes a plurality of wavelength convertor elements of the wavelength convertor for converting the portion of the solar radiation as the collected radiation is guided by the light guide.

31. The photosynthetic growth apparatus of any one of claims 27-30, wherein the light guide is configured to separate the wavelength convertor and/or the at least one solar collector from the photosynthetic material to at least substantially reduce any effect of heat from the wavelength convertor and/or the at least one solar collector on the photosynthetic material.

32. The photosynthetic growth apparatus of any one of claims 27-31, wherein the light guide includes a plurality of light panels to spatially distribute light across the at least one growth area.

33. The photosynthetic growth apparatus of any one of claims 1-32, wherein the at least one growth area includes at least one growth chamber configured to transmit the collected radiation and the converted radiation from the light guide to the photosynthetic material.

34. The photosynthetic growth apparatus of claim 33, wherein the at least one growth chamber includes a plurality of side walls transparent to radiation of the at least one selected wavelength.

35. The photosynthetic growth apparatus of any one of claims 33 and 34, wherein the at least one growth chamber is configured to allow fluid flow to and from the photosynthetic material.

36. The photosynthetic growth apparatus of any one of claims 33-35, wherein the at least one growth chamber is in the form of a replaceable container.

37. The photosynthetic growth apparatus of claim 36, wherein sparging features are integrally formed in the replaceable container.

38. The photosynthetic growth apparatus of claim 37, wherein the sparging features include perforations between separate compartments of the at least one growth chamber.

39. The photosynthetic growth apparatus of any one of claims 1-38, including at least one wavelength separator configured to separate portions of the solar radiation that do not have the at least one selected wavelength for use in heat generation and/or photovoltaic electricity generation.

40. The photosynthetic growth apparatus of any one of claims 1-39, including at least one wavelength separator having at least one wavelength-selective surface configured to separate portions of solar radiation having the at least one selected wavelength from portions not having the at least one selected wavelength.

41. The photosynthetic growth apparatus of claim 40, wherein the at least one wavelength- selective surface includes a dichroic reflective coating.

42. The photosynthetic growth apparatus of any one of claims 1-41, wherein the wavelength converter uses Stokes fluorescence to convert the solar radiation.

43. The photosynthetic growth apparatus of claim 42, wherein the Stokes fluorescence is provided by a semiconductor material, and the semiconductor material includes a plurality of semiconductor quantum dots (QDs).

44. The photosynthetic growth apparatus of claim 43, wherein the converted radiation has a wavelength based on a morphology and/or dielectric environment of the QDs.

45. The photosynthetic growth apparatus of any one of claims 1—44, wherein the photosynthetic material includes microalgae.

46. A photosynthetic growth system including: the photosynthetic growth apparatus of any one of the preceding claims; and a fluidic processing system for supplying the photosynthetic material with input matter for the photosynthesis.

47. A photosynthetic growth facility for capturing carbon dioxide using photosynthesis including: a plurality of the photosynthetic growth systems of claim 46; and a control system for controlling the photosynthetic growth apparatuses and the fluidic processing systems.

48. The photosynthetic growth facility of claim 47, wherein the at least one solar collector includes an array of solar collectors forming a roof.

49. The photosynthetic growth facility of claim 48, wherein the roof is substantially sealed to fluid and/or temperature.

50. A method of performing photosynthesis including the steps of: collecting solar radiation; converting at least a portion of the collected solar radiation having one or more wavelengths different from at least one selected wavelength to radiation with the at least one selected wavelength; performing photosynthesis using photosynthetic material and the radiation having the at least one selected wavelength; and controlling irradiation of the photosynthetic material by the radiation having the at least one selected wavelength to at least substantially reduce photoinhibition of the photosynthesis.

51. A method of performing photosynthesis including the steps of: collecting solar radiation; converting a portion of the solar radiation that does not have at least one preferred wavelength for photosynthesis by a photosynthetic material into light having at least one preferred wavelength; controlling the intensity of the collected radiation and the converted radiation to at least substantially reduce photoinhibition of the photosynthesis; and performing the photosynthesis using the collected radiation and the converted radiation.

52. A photosynthetic growth apparatus including: at least one solar collector configured to collect solar radiation; a wavelength converter configured to convert a portion of the solar radiation that does not have at least one preferred wavelength for photosynthesis by a photosynthetic material into radiation having at least one preferred wavelength for photosynthesis by the photosynthetic material; a light modulator configured to control the intensity of the collected radiation and the converted radiation to at least substantially reduce photoinhibition of the photosynthesis; and photosynthetic material for performing the photosynthesis using the collected radiation and the converted radiation.

53. A solar collector including: at least one reflector, fixed relative to movement of the sun, configured to concentrate solar radiation to a moving region; and at least one moving receiver configured to move to receive the concentrated solar radiation in the region.