WO2023094970A1

WO2023094970A1 - Transparent photo-to-thermal energy conversion module and method

Info

Publication number: WO2023094970A1
Application number: PCT/IB2022/061229
Authority: WO
Inventors: Derya Baran; Daniel Thomas James BRYANT; Ashley PURSGLOVE
Original assignee: King Abdullah University Of Science And Technology
Priority date: 2021-11-23
Filing date: 2022-11-21
Publication date: 2023-06-01

Abstract

A photo-to-thermal energy conversion module (100) includes first and second walls (102, 104) that extend in different, parallel planes, plural separation walls (106- I) that contact both the first and second walls (102, 104) and extend perpendicular to the first and second walls (102, 104), an internal chamber (110) defined by the first wall (102), second wall (104), and first and second separation walls of the plural separation walls (106-1), and a particulate mixture (211) distributed around the internal chamber (110), the particulate mixture (211) including an organic component (212) and an inorganic component (214). The organic component (212) is configured to absorb a first amount of near infrared light, NIR, (424) having a wavelength larger than 700 nm and to generate a first amount of heat, the inorganic component (214) is configured to absorb a second amount of the NIR (424) having a wavelength larger than 700 nm and to generate a second amount of heat, and the first and second walls include a polymeric matrix (210) that is configured to allow visible light (422) to pass through, where the visible light (422) has a wavelength between 400 and 700 nm.

Description

TRANSPARENT PHOTO-TO-THERMAL ENERGY CONVERSION

MODULE AND METHOD

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application No. 63/264,487, filed on November 23, 2021 , entitled “TRANSPARENT SOLARTHERMAL CONVERTERS,” the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

TECHNICAL FIELD

[0002] Embodiments of the subject matter disclosed herein generally relate to a module and method for transforming solar photo-energy into thermal energy, and more particularly, to a photo-to-thermal energy conversion module that may be used as part of a building for allowing the visible light to enter the building, but simultaneously transforming a broad spectrum of the near-infrared portion of the solar spectrum into heat and then channeling the heat away from the interior of the building.

DISCUSSION OF THE BACKGROUND

[0003] Currently, in hot climates such as the Gulf countries, the removal of heat from a building requires a large amount of energy, which is the biggest domestic energy use. Buildings such as residential buildings, office buildings, some commercial buildings, greenhouses, and livestock environments require natural visible sunlight having a spectrum between 400-700 nm to enter the building (as visible light for humans or photosynthetically active radiation (PAR) light for plants) through windows or otherwise transparent building panel materials. However, the near infrared region (NIR) portion of the sun’s emitted solar spectrum, between 700- 2500 nm, is the biggest contributor to solar heat gain in a building and this portion of the sun spectrum is undesired for these buildings.

[0004] Blocking as much of the NIR spectrum as possible, before it enters the building, whilst leaving the visible and PAR spectrum as high as is required, remains a challenge for the construction industry. Similarly, if the NIR is absorbed by the window/panels it would cause the window/panels to increase their temperature and get hot. Thus, the thermal energy radiates inside the building, contributing to its heating, unless the heat is somehow removed from the panel. To this extent, the absorbed NIR is currently deemed as ‘waste heat’ and one that currently offers little value.

[0005] Today, most of the windows used in the commercial and residential buildings are two-pane windows, where a gas is hold between two glass plates. However, there is currently no mechanism in place to either prevent the NIR spectrum from entering the building or to remove the heat carried by the NIR spectrum through the two-pane window.

[0006] Thus, there is a need for a new structure that allows visible light to enter into a building but simultaneously, to prevent the heat associated with the NIR spectrum from entering the same building.

SUMMARY OF THE INVENTION

[0007] According to an embodiment, there is a photo-to-thermal energy conversion module that includes first and second walls that extend in different, parallel planes, plural separation walls that contact both the first and second walls and extend perpendicular to the first and second walls, an internal chamber defined by the first wall, second wall, and first and second separation walls of the plural separation walls, and a particulate mixture distributed around the internal chamber, the particulate mixture including an organic component and an inorganic component. The organic component is configured to absorb a first amount of near infrared light, NIR, having a wavelength larger than 700 nm and to generate a first amount of heat, the inorganic component is configured to absorb a second amount of the NIR having a wavelength larger than 700 nm and to generate a second amount of heat, and the first and second walls include a polymeric matrix that is configured to allow visible light to pass through, where the visible light has a wavelength between 400 and 700 nm.

[0008] According to another embodiment, there is a heat extraction system that includes a photo-to-thermal energy conversion module including a particulate mixture distributed around an internal chamber, the particulate mixture including an organic component and an inorganic component. The organic component is configured to absorb a first amount of near infrared light, NIR, having a wavelength larger than 700 nm and to generate a first amount of heat, and the inorganic component is configured to absorb a second amount of the NIR having a wavelength larger than 700 nm and to generate a second amount of heat. The system further includes an inlet port configured to receive a fluid, the inlet port being fluidly connected to the internal chamber, an outlet port configured to discharge a heated fluid, the outlet port being fluidly connected to the internal chamber, and a motor fluidly connected to the inlet or outlet port and configured to move the fluid through the internal chamber to collect the first and second amounts of heat and to generate the heated fluid.

[0009] According to yet another embodiment, there is a method for making a photo-to-thermal energy conversion module, and the method includes selecting an organic component to absorb a first amount of near infrared light, NIR, having a wavelength larger than 700 nm and to generate a first amount of heat, selecting an inorganic component to absorb a second amount of the NIR having a wavelength larger than 700 nm and to generate a second amount of heat, blending the organic and inorganic components with a polymeric material to form a blend, extruding the blend to form a masterbatch, mixing the masterbatch with a bulk polymer, and extruding the module from the masterbatch and the bulk polymer. The module has first and second walls that are configured to allow visible light to pass through, where the visible light has a wavelength between 400 and 700 nm.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] For a more complete understanding of the present invention, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

[0011] Figure 1 is a schematic diagram of a photo-to-thermal energy conversion module that absorbs NIR light and transmits visible light, and the NIR light is transformed into thermal energy;

[0012] Figure 2A schematically illustrates a polymeric matrix holding organic and inorganic components within walls of the module;

[0013] Figure 2B schematically illustrates the organic and inorganic components coating an exterior of the walls of the module;

[0014] Figure 3 schematically illustrates an internal chamber of the module fluidly connected to inlet and outlet ports for receiving a fluid flow to remove the thermal energy from the module;

[0015] Figure 4 illustrates a heat extraction system that uses the module of

Figure 1 to extract heat from incoming solar radiation;

[0016] Figure 5 illustrates another heat extraction system that uses the module of Figure 1 to extract heat from the incoming solar radiation;

[0017] Figure 6 is a flow chart of a method for making a solution that includes the organic and inorganic components and the solution can coat the module; [0018] Figure 7 is a flow chart of a method for forming the module to have the organic and inorganic components distributed within its walls;

[0019] Figure 8 is a flow chart of a method for forming the module by extruding the organic and inorganic components and a bulk polymer;

[0020] Figure 9 illustrates the light transmission of a module formed with a first particulate mixture of the organic and inorganic components;

[0021] Figure 10 illustrates the light transmission of a module formed with a second particulate mixture of the organic and inorganic components;

[0022] Figure 11 illustrates the temperatures inside a reference module and a module made as illustrated in Figure 1 ; and

[0023] Figure 12 illustrates the instantaneous energy flux and the cumulative energy generated by the module of Figure 1 when exposed to solar radiation.

DETAILED DESCRIPTION OF THE INVENTION

[0024] The following description of the embodiments refers to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. The following detailed description does not limit the invention. Instead, the scope of the invention is defined by the appended claims. The following embodiments are discussed, for simplicity, with regard to a photo-to-thermal energy conversion module that is used as part of a roof of a building, for absorbing the NIR light and removing the heat associated with it before entering the building.

However, the embodiments to be discussed next are not limited to using the photo- to-thermal energy conversion module onto the roof of a building, but may be applied to any other structure that require visible solar light but not heat associated with the NIR spectrum of the solar light. For example, the photo-to-thermal energy conversion module may be used as a window or a stand-alone module/panel. In one application, the photo-to-thermal energy conversion module is used with non-solar light, i.e. , artificially generated light.

[0025] Reference throughout the specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrases “in one embodiment” or “in an embodiment” in various places throughout the specification is not necessarily referring to the same embodiment. Further, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.

[0026] It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first object or step could be termed a second object or step, and, similarly, a second object or step could be termed a first object or step, without departing from the scope of the present disclosure. The first object or step, and the second object or step, are both, objects or steps, respectively, but they are not to be considered the same object or step.

[0027] The terminology used in the description herein is for the purpose of describing particular embodiments and is not intended to be limiting. As used in this description and the appended claims, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the term "and/or" as used herein refers to and encompasses any possible combinations of one or more of the associated listed items. It will be further understood that the terms "includes," "including," "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. Further, as used herein, the term "if" may be construed to mean "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. [0028] According to an embodiment, a novel photo-to-thermal energy conversion module includes a hollow two-walled structure embedded or painted with a particulate mixture that includes (1 ) a light absorbing organic component (simply called herein the “organic component”) which absorbs light having a wavelength larger than 750 nm and (2) an inorganic material (simply called herein the “inorganic component”) which absorbs light having a wavelength larger than 750 nm. The twowalled structure absorbs in the NIR range and transmits in the visible/PAR range. In one application, the particulate mixture of the photo-to-thermal energy conversion module is selected so that the organic component absorbs in the region close to the visible/PAR in the 700-1000 nm range, and the inorganic component absorbs in the 1000-2500 nm. Those skilled in the art would understand that the organic and inorganic components discussed above may be selected such that the two ranges vary between 10 and 30%, i.e., the boundary value of 1000 nm can be smaller or larger. By using both components in combination within a single host polymer matrix, a broad NIR absorption spectrum can be achieved. In addition, in one application, a sharp absorption peak due to the direct band gap of the organic component, allows for an absorption close to the edge of 700 nm without a significant compromise in the absorption of the red portion of the spectrum. All selected materials exhibit a high visible/PAR transmission, even when used in combination, due to their small density per surface area of the module.

[0029] The photo-to-thermal energy conversion module is now discussed in more detail with regard to the figures. In terms of its shape, a photo-to-thermal energy conversion module 100 can have a multi-wall shape, as shown in Figure 1 . The module 100 has a first (or bottom) wall 102, a second (or top) wall 104, and plural separation walls 106-I (where I is an integer equal to or larger than 2) that separate the first wall from the second wall. In one embodiment, the first and second walls extend in parallel planes, and the separation walls extend perpendicular to the parallel planes. A distance d between the two walls 102 and 104 can be in mm or cm range. Two adjacent separation walls 106-1 and 106-1, together with the first and second walls, define an internal chamber 110. The device module may have one or more such internal chambers 1 10. In one application, plural internal chambers are connected in series among them while in another embodiment, the plural internal chambers are fluidly connected in parallel to each other.

[0030] The first wall, the second wall, and the separation walls may be made of a transparent matrix 210 (see Figure 2A), for example, a polymer like a low- density polyethylene LDPE, polycarbonate (PC) or polymethyl methacrylate (PMMA). In one application, it is possible to use glass or other transparent material for the transparent matrix 210. The transparent matrix 210 is configured to hold a particulate mixture 21 1 , which includes the organic component 212 and the inorganic component 214. In one application, the particulate mixture 211 is uniformly distributed within the transparent matrix 210. In another embodiment, the particulate mixture is coating an exterior of the transparent matrix. In yet another embodiment, the particulate mixture is located only on the first and second walls. In still another embodiment, the particulate matrix is located only on the top wall.

[0031] The organic component 212 may be small-molecules, oligomers and polymers. In one application, the organic component 212 has a main absorption peak beyond (higher than) 750 nm. For example, the organic component may include: Metal Dithiolene, Napthacyanine, Phatlacyanies, Diimonium Salts, Perylene, Quaterrylene, Metal-Complexes, polythiophenes, Cyanines. In one application, the selected organic material may be low-radiative, and has a high molar extinction coefficient. The inorganic component 214, which is also hold by the matrix 210, is selected to be a material with a strong absorption above 750 nm. For example, the inorganic component is selected to have polaron absorption and localized surface plasmonic resonance. Both of these properties require the material to be a conductor or semi-conductor. Such materials include: doped tungsten oxides, copper sulphides, tin oxides. The materials for the NIR absorption are desired to have low photoelectric and re-emission properties, i.e., to not reemit the absorbed NIR spectrum, so that they efficiently convert the photo energy into thermal energy.

[0032] In one application, additional materials 216 may optionally be added to the particulate mixture 211 , in the matrix 210, for example, materials which absorb in the mid-IR and far-IR. These materials can absorb IR radiation any reemit radiation in those regions, such as reemitted mid-IR from the greenhouse materials and the ground. Such a material may include aluminosilicates such as sodium aluminosilicates (trade name Sipernat 802A). In one application, the additional material 216 may include scattering particles (beneficial for horticulture and areas where humans are behind), anti-drop (wetting agents which stop droplets forming on the panels, causing roof-rain), anti-static (makes the material easier to clean), other wavelength specific absorbing materials (dyes which absorb in the visible for applications which might not need so much visible light, e.g., green light). [0033] Figure 2A shows the organic component 212, the inorganic component 214, and the optional additional materials 216, i.e., the particulate mixture 211 , as being distributed into the structure of the matrix 210. However, as illustrated in Figure 2B, it is possible to integrate the particulate mixture 211 into a solution 220 and to apply the solution, similar to a paint, to the walls 102, 104 and/or 106 instead of incorporating the materials into the structure of the walls. In this way, an existing structure that includes transparent walls that forms an internal chamber can be painted with the materials 212 and 214 to achieve the photo-to-thermal energy conversion function of the module 100.

[0034] By using a multi-walled module 100 having one or more internal chambers 110, it allows a liquid or gas 310 to be flowed through the internal chambers of the module as illustrated in Figure 3. For this purpose, the internal chambers 110 of the module 100 may be fluidly connected to each other in series (they also can be connected in parallel), as schematically illustrated in Figure 3. An input port 320 is fluidly attached to the beginning of a first internal chamber 110 and an output port 322 is fluidly attached to the end of a last internal chamber 110 (if plural internal chambers are present). In this way, the fluid 310 enters at one end of the module 110 and exits at the same or opposite end of the module. The fluid 310 can then act as a thermal transfer medium whereby the excess heat of the module 100 generated within the internal chambers 110, from absorbing the incoming NIR radiation, can be transferred to the medium 310 and then physically transported away, outside the module 100. [0035] In one application, the hot medium 312 discharged at output port 322 may be collected as it exits the module 100 and can be utilized as an energy source, e.g., for processes such as adsorption and absorption chilling. Thus, in this application, the module 100 can act to have a multi-function purpose, as a transparent solar thermal collector, a visible/PAR light window, and a heat-blocking window. More specifically, as shown in Figure 4, the module 100 is integrated with a heat exchanger 410 and corresponding piping 412 and 414 in a heat extraction system 400 for using the removed heat from the module to heat a cooled air or liquid stream 416 from a process, to generate a heated air or liquid stream 418. For example, the cooled stream 416 maybe cold air in air conditioning system and the heated stream 418 may be heated air in the same system. The solar radiation 420 interacts with the module 100 and most of the NIR radiation is absorbed by the particulate mixture 21 1 and transformed into heat. The medium 310, air in this case, is taking this heat and is moving it along the pipe 414 to the heat exchanger 410, to heat the stream 416. The cooled air stream is then returned along pipe 412 to the module 100, to further remove heat. In one application, the heat exchanger 410 includes a pump or motor 41 1 which pushes the air stream through the module 100. This process may be controlled by a controller 430, i.e. , for how long the air stream is flown through the module 100 (e.g., only during the day) and how large the air flow is through the module (e.g., small when cloudy, but large when sunny). The controller 430 may be located in a chamber 440, where it is controlled by the operator by the chamber, and this chamber may be configured to receive the heated stream 418. The chamber may be a residential room, an office, a barn, a shop, etc. Note that Figure 4 shows that only the visible radiation 422 passes through the module 100 while most of the NIR radiation 424 is absorbed by the particulate mixture 211 . Figure 5 shows another heat extraction system 500 that uses the heated air from the module 100 to heat a cold water stream 416 to generate hot water 418. Thus, in this system, the chamber 440 is replaced by a hot water tank 510, that holds water 512. In both embodiments, the systems 400 and 500 are integrated into a building/structure 450. More specifically, as shown in Figure 4, the module 100 is integrated into the roof 452 of the building 450. However, it is also possible to implement the module 100 as a window into a wall 454 of the building 450. As previously discussed, the building 450 may be a residential, commercial, industrial, agricultural or farm related building.

[0036] The above discussed embodiments highlight that the particulate composition 211 and associated module 100 can be used as structural panels to be manufactured with conventional cross-sections and thicknesses as appropriate for the construction field. This results in the transparent-NIR absorbing module 100 being able to be used in a building fabrication, creating a building integrated solar collector (BISC). Thus, it is possible to use the module 100 within the regular building construction environment.

[0037] A method for making the solution 220 discussed above is now presented with regard to Figure 6. The method includes a step 600 of selecting the inorganic component so that is absorbs at least a part of the spectrum from 700 to 2200 nm. In one application, plural inorganic materials are selected, e.g., a first inorganic material for absorbing the NIR in the 1000 to 1700 nm range and a second inorganic material for absorbing the NIR in the 1700 to 2200 nm range. One skilled in the art would understand that these numbers are provided as an example, and any range in the 700 to 2200 nm range may be selected for the first inorganic material and any other range (overlapping or not the first range) may be selected for the second inorganic material. Any range may be targeted in the 700 to 2200 nm range. Also, those skilled in the art would understand that the selection of the inorganic material is dependent on the selection of the organic material, so that their combined ranges cover the 700 to 2200 nm range. In step 602, the inorganic particles (commonly nanoparticles) are milled with a surfactant. For example, CsWOa nanoparticles (the inorganic component) are placed in a ball mill with Anti-Terra-U surfactant (BYK) and milled. In step 604, a solvent binder solution is made by dispersing an acrylate-based polymer in a solvent, e.g., Paraloid B-72 in acetone. In step 606 the surfactant covered CsWOa nanoparticles are added to the solvent binder solution formed in step 604 and stirred. In step 608, an organic component is selected to absorb the NIR radiation in the range of 700 to 1000 nm. Other ranges may be used as long as the organic and inorganic components cover the 700 to 2200 nm or even 2500 nm range. Note that the 2200 nm upper limit of this range is not a hard upper limit, i.e. , this upper limit of the desired range can vary upward or downward by about 50%. Thus, in this application, the term “about” is used to refer to a specific number that can vary up or down by 50%. The organic component (more than one is possible to be added, for example, IEICO-4F (2,2'-((2Z,2'Z)- (((4,4,9,9-tetrakis(4-hexylphenyl)-4,9-dihydro-sindaceno[1 ,2-b:5,6-b']dithiophene-2,7- diyl)bis(4-((2-ethylhexyl)oxy)thiophene-5,2-diyl))bis(methanylylidene))bis(5,6- difluoro-3-oxo-2,3-dihydro-1 /-/-indene-2,1-diylidene))dimalononitrile), Epolight 4019 (from Epolin), and/or Lumogen 788 (Quaterrylene dye, BASF) is added in step 610 to the solution and further mixed. This solution (or paint 220) can then be coated onto a substrate, such as glass or a transparent polymer, via traditional methods such as spray, brush, roller and bar coating to fix the particulate mixture 211 to that substrate.

[0038] However, if the particulate mixture 211 is desired to be formed within the walls of the module 100, as shown in Figure 2A, then a different method is used, as now discussed with regard to Figure 7. Two methods, masterbatching or compounding, are commonly used for polymer processing. Masterbatching is a cheaper method as less mass of polymer has to be processed across the 2-steps, i.e., in masterbatching, 1 kg is made in step 1 for every 166 kg of product extruded in step 2, but in compounding, 100 kg of compound needs to be made in step 1 for every 100 kg of product extruded in step 2. However, compounding gives more control over the exact composition and distribution of the organic and inorganic components that end up in the module 100.

[0039] With regard to the masterbatching, a dispersed concentrated pellet is made, which is added to a polymer extrusion processing. More specifically, in step 700, the NIR absorbing components 212 and 214 are selected, and in step 702 these components and other contributing materials (e.g., material 216) are blended with a carrier material in a twin screw extruder. In one application, a concentration in % of the total components in the carrier material are 4-10%wt in 90-96%wt polymer carrier, e.g., 5% the inorganic component 214 (CsWOa nanoparticles) + 1% the organic component 212 (e.g., Epolight 4019 (Metal Dithiolene dye, Epoli n)) in 94% PC 0703R (polycarbonate resin, SABIC). The resulting material is extruded from the twin screw extruder in step 704, forming a material known as the masterbatch. In step 706, the masterbatch is added to a bulk polymer (for example, so that a final concentration of the particulate mixture is about 0.001 to 0.1% of the total polymer), during an extrusion process, either with a single screw or twin-screw extruder, and extruded in step 708 into a finished product, e.g., 0.6%wt of masterbatch is added to 99.4% polymer PC 0703R (polycarbonate resin, SABIC) into a single screw extruder, where it is heated, melted and forced through a die into a hollow-multiwall profile of a fixed width, which is then cut into the desired panel length.

[0040] The other method, compounding, uses the final polymer pellet made in step 704 directly into step 708 with no other additions or mixing needed. More specifically, in step 800 of Figure 8, the NIR absorbing components 212 and 214 are selected. In step 802, the NIR absorbing components 212 and 214 and other contributing materials are blended with the bulk polymer material in a twin screw extruder, e.g., 0.03% for the inorganic component (for example, CsWOa nanoparticles) + 0.006% for the organic component (for example, Epolight 4019 (Metal Dithiolene dye, Epolin)) in 99.964% PC 0703R (polycarbonate resin, SABIC). This is known as the compound or compounded material. Then, in step 804, the compound is fed into a single or twin-screw extruder, and extruded into a finished product 100, e.g., 100% of the compound is fed into a single screw extruder, where it is heated, melted and forced through a die into a hollow-multiwall profile of a fixed width, which is then cut into the desired panel length. [0041] The bulk polymers tested by the inventors for the matrix 210 include Acrylic/Polyacrylate (PMMA), Polycarbonate (PC), Polyethylene, high-density, low- density and linear low density (HDPE, LDPE, LLDPE), Ethylene Vinyl Acetate (EVA), and polyvinyl butyral (PVB). However, other polymers or combinations of polymers may be used as long as at least 80% of the incident visible light to such a polymer passes through the formed module 100.

[0042] For a module 100 having a wall thickness of 6mm, and being extruded from polycarbonate (1 ,300g/m²), containing about 0.6%wt NIR masterbatch of about 6% CsWC>3 and about 0.6% Epolight 4019, the transmission light in percentage versus the wavelength of the incident light was found to be as illustrated in Figure 9. It is noted that the high transmission of the visible light (up to about 700 nm) and the good absorption of the NIR spectrum (between 750 and 2200 nm) validates the above discussed characteristics of the module 100. When the same measurements were repeated for a 16mm thick module 100, extruded from PMMA (4,400g/m²), containing 0.5%wt addition of NIR masterbatch of 6% CsWOa and 0.6% Epolight 4019, the measured transmission was found as illustrated in Figure 10. It is noted that the NIR spectrum is almost extinguished in the region from 1000 to 2500 nm. In yet another example, a module 100 was made of a 2mm thick PVB film with about 0.01 wt% Epolight 4019, about 0.02wt% Cesium Tungsten Oxide and about 1% Sipernat 820a.

[0043] It is noted that a mass of the organic component 212 in the module 100 ranges from 1 -1000 mg per meter square of polymer (independent of polymer thickness) and a mass of the inorganic component 214 ranges from 100-1000 mg per meter square of polymer (independent of polymer thickness). Thus, for a multiwalled NIR absorbing solar thermal module 100 with 2mm thickness walls, the expected % additions would be: organic component 212 in the range 0.005-0.02wt% and the inorganic component in the range of 0.01 -0.04wt% respective to the polymer matrix.

[0044] To estimate the efficiency of the module 100, PMMA multi-walled panels with and without NIR absorbing materials were made. The two panels were fabricated as follows: Panel 1 ): a transparent reference panel was fabricated from 1 x1 m sheets of 4mm transparent PMMA acrylic sheets. At 25 cm distances, 10 mm transparent PMMA spacer bars were added to the length of the sheets, adhered with 1 mm acrylic VHB tape on both sides. Another 1 x 1 m 4 mm PMMA sheet was layered on top to create the reference multi-walled PMMA panel with overall dimensions: 1000x1000x20 mm and with 4x internal cavities of dimensions 1000x240x12 mm. Panel 2), which is a NIR-absorbing multi-walled panel, was fabricated in the same fashion as Panel 1 , however, the internal cavity was coated with the particulate mixture 211 , which included a blend of CsWOa and IEICO-4F with an acrylate-based coating, to form a layer of NIR absorbing acrylate material on the surface of the internal cavity.

[0045] On both panels, the open parts of the internal cavity (top and the bottom) were sealed with a length of tubing with a section cut-out for the panel. Both panels were left outside at KAUST University (Thuwal, KSA) and exposed to the sun at an angle parallel to the ground. The temperature of the panels was allowed to stabilize for approximately 30 minutes and then the internal temperature of the panels was measured. The panels achieved the following temperatures as an average of the 4 internal cavities measured at 3 different locations inside the panel:

[0046] Panel 1 (reference): 42.6°C

[0047] Panel 2 (NIR material): 63.3°C

[0048] Ambient Air Temperature: 37.8°C

[0049] It is noted from these measurements that the NIR particulate mixture 211 used for the Panel 2 transforms part of the NIR radiation into heat, which results in the increased temperature inside the panel. The panels in this experiment were not connected to a pump for moving a gas or liquid through the cavities to remove that heat.

[0050] In another experiment, the Panel 2 (which corresponds to module 100 of Figure 1 ) was placed on the roof a structure and the ambient air temperature 11 10 and the panel’s temperature 11 12 were measured over a certain time, as illustrated in Figure 11. It is noted that the temperature of the panel was about 24 °C higher than the ambient air temperature. For this experiment, a pump was run so that the heated air inside the cavities of the panel was continuously replaced with fresh air. In this experiment, the airflow through the module 100 was about 4.2 m/s, indicated by curve 11 14 in the figure. Converting the volumetric airflow to a mass airflow via the air density at the given temperature, it is possible to calculate the instantaneous heat flux with respect to the change in temperature, as illustrated in Figure 12 by curve 1210. If the instantaneous energy flux 1210 is integrated, it is possible to obtain the cumulative energy harvested by the module 100, as illustrated by curve 1220 in Figure 12. [0051] These experiments prove the energy harvesting function of the modules 100, in addition to the capability of allowing the visible light to pass through, which make these materials suitable for the construction sector (residential, commercial, industrial or farm buildings). Thus, a photo-to-thermal energy conversion module may be made to include first and second walls 102, 104 that extend in different, parallel planes, plural separation walls 106-1 that contact both the first and second walls 102, 104 and extend perpendicular to the first and second walls 102, 104, an internal chamber 110 defined by the first wall 102, second wall 104, and first and second separation walls of the plural separation walls 106-1, and a particulate mixture 21 1 distributed around the internal chamber 1 10, the particulate mixture 21 1 including an organic component 212 and an inorganic component 214. The organic component 212 is configured to absorb a first amount of near infrared light, NIR, 424 having a wavelength larger than 700 nm and to generate a first amount of heat, the inorganic component 214 is configured to absorb a second amount of the NIR 424 having a wavelength larger than 700 nm and to generate a second amount of heat, and the first and second walls include a polymeric matrix 210 that is configured to allow visible light 422 to pass through, where the visible light 422 has a wavelength between 400 and 700 nm

[0052] The disclosed embodiments provide a visible light transparent module that acts as an energy collector for the NIV radiation and this module has enough strength to be used in the construction sector. It should be understood that this description is not intended to limit the invention. On the contrary, the embodiments are intended to cover alternatives, modifications and equivalents, which are included in the spirit and scope of the invention as defined by the appended claims. Further, in the detailed description of the embodiments, numerous specific details are set forth in order to provide a comprehensive understanding of the claimed invention. However, one skilled in the art would understand that various embodiments may be practiced without such specific details.

[0053] Although the features and elements of the present embodiments are described in the embodiments in particular combinations, each feature or element can be used alone without the other features and elements of the embodiments or in various combinations with or without other features and elements disclosed herein.

[0054] This written description uses examples of the subject matter disclosed to enable any person skilled in the art to practice the same, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the subject matter is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims.

Claims

24 WHAT IS CLAIMED IS:

1 . A photo-to-thermal energy conversion module (100) comprising: first and second walls (102, 104) that extend in different, parallel planes; plural separation walls (106-1) that contact both the first and second walls (102, 104) and extend perpendicular to the first and second walls (102, 104); an internal chamber (1 10) defined by the first wall (102), second wall (104), and first and second separation walls of the plural separation walls (106-1); and a particulate mixture (21 1 ) distributed around the internal chamber (110), the particulate mixture (211 ) including an organic component (212) and an inorganic component (214), wherein the organic component (212) is configured to absorb a first amount of near infrared light, NIR, (424) having a wavelength larger than 700 nm and to generate a first amount of heat, wherein the inorganic component (214) is configured to absorb a second amount of the NIR (424) having a wavelength larger than 700 nm and to generate a second amount of heat, and wherein the first and second walls include a polymeric matrix (210) that is configured to allow visible light (422) to pass through, where the visible light (422) has a wavelength between 400 and 700 nm.

2. The module of Claim 1 , wherein the particulate mixture is distributed within the polymeric matrix.

3. The module of Claim 1 , wherein the particulate mixture is coating an exterior of the polymeric matrix.

4. The module of Claim 1 , wherein the particulate mixture is located only on the first and second walls.

5. The module of Claim 1 , wherein the inorganic component includes CsWOa nanoparticles.

6. The module of Claim 1 , wherein the organic component includes metal dithiolene.

7. The module of Claim 1 , wherein the organic component is selected to absorb NIR having a range of about 700 to 1000 nm while the inorganic component is selected to absorb NIR having a range of about 1000 to 2500 nm.

8. The module of Claim 1 , wherein a mass of the organic component ranges between 1 and 1000 mg per meter square of the polymeric matrix.

9. The module of Claim 1 , wherein a weight percentage of the organic component ranges from 0.005 to 0.02 of a weight of the polymeric matrix.

10. The module of Claim 1 , wherein a mass of the inorganic component ranges between 100 and 1000 mg per meter square of the polymeric matrix.

1 1 . The module of Claim 1 , wherein a weight percentage of the inorganic component ranges from 0.01 to 0.04 of a weight of the polymeric matrix.

12. The module of Claim 1 , further comprising: an input port fluidly connected to the internal chamber; and an output port fluidly connected to the internal chamber, wherein the input port is configured to receive a fluid and the output port is configured to discharge the fluid after passing the internal chamber and removing heat generated by the absorption of the NIR.

13. A heat extraction system (400) comprising: a photo-to-thermal energy conversion module (100) including a particulate mixture (21 1 ) distributed around an internal chamber (110), the particulate mixture (211 ) including an organic component (212) and an inorganic component (214), wherein the organic component (212) is configured to absorb a first amount of near infrared light, NIR, (424) having a wavelength larger than 700 nm and to generate a first amount of heat, wherein the inorganic component (214) is configured to absorb a second amount of the NIR (424) having a wavelength larger than 700 nm and to generate a second amount of heat; 27 an inlet port (320) configured to receive a fluid (310), the inlet port (320) being fluidly connected to the internal chamber (110); an outlet port (322) configured to discharge a heated fluid (312), the outlet port (322) being fluidly connected to the internal chamber (110); and a motor (411 ) fluidly connected to the inlet or outlet port and configured to move the fluid (310) through the internal chamber (1 10) to collect the first and second amounts of heat and to generate the heated fluid (312).

14. The system of Claim 13, wherein the module includes: first and second walls (102, 104) that extend in different, parallel planes; plural separation walls (106-1) that contact both the first and second walls

(102, 104) and extend perpendicular to the first and second walls (102, 104); and the internal chamber (110) defined by the first wall (102), second wall (104), and first and second separation walls of the plural separation walls (106-1), wherein the first and second walls include a polymeric matrix (210) that is configured to allow visible light (422) to pass through, where the visible light (422) has a wavelength between 400 and 700 nm.

15. The system of Claim 14, wherein the particulate mixture is distributed within the polymeric matrix.

16. The system of Claim 14, wherein the particulate mixture is coating an exterior of the polymeric matrix. 28

17. The system of Claim 14, wherein the inorganic component includes CsWC>3 nanoparticles.

18. The system of Claim 14, wherein the organic component includes metal dithiolene.

19. The system of Claim 14, wherein the organic component is selected to absorb NIR having a range of about 700 to 1000 nm while the inorganic component is selected to absorb NIR having a range of about 1000 to 2500 nm.

20. A method for making a photo-to-thermal energy conversion module (100), the method comprising: selecting (700) an organic component (212) to absorb a first amount of near infrared light, NIR, (424) having a wavelength larger than 700 nm and to generate a first amount of heat; selecting (700) an inorganic component (214) to absorb a second amount of the NIR (424) having a wavelength larger than 700 nm and to generate a second amount of heat; blending (702) the organic and inorganic components (212, 214) with a polymeric material to form a blend; extruding (704) the blend to form a masterbatch; mixing (706) the masterbatch with a bulk polymer; and 29 extruding (708) the module (100) from the masterbatch and the bulk polymer, wherein the module has first and second walls that are configured to allow visible light (422) to pass through, where the visible light (422) has a wavelength between 400 and 700 nm.