阅读说明：本技术 用于缓解太阳能加热的系统 (System for mitigating solar heating ) 是由 N·F·博雷利 G·L·布切尔 W·塞钠拉特纳 S·Y·坦 于 2019-01-10 设计创作，主要内容包括：运载工具的顶部包括被动冷却层,其铺盖顶部的向外表面,使得所述层暴露于运载工具外部的日光。所述层包括分子结构具有Si-O-Si连接的聚合物。所述层在太阳能加热的峰值波谱内具有相对较高的发射率。(The roof of the vehicle includes a passive cooling layer that covers the outward facing surface of the roof such that the layer is exposed to sunlight outside the vehicle. The layer includes a polymer having a molecular structure with Si-O-Si linkages. The layer has a relatively high emissivity in the peak spectrum of solar heating.)

1. A vehicle having solar heating mitigation, comprising:

a body having a top, wherein at least a portion of the top is opaque to sunlight in a visible range; and

a passive cooling layer overlaying the portion of the roof on an outward surface of the roof to expose the layer to light outside the vehicle,

wherein the layer comprises a polymer,

wherein the layer comprises a molecular structure having Si-O-Si linkages, and

wherein the layer has a thickness and a concentration of Si-O-Si connections such that the layer has an absorption of greater than 80% for light at a wavelength of 10 μm.

2. The vehicle of claim 1 wherein the portion of the top that is opaque to sunlight comprises painted metal, wherein the layer overlies the painted metal, wherein the transmission of light through the layer is at least 80% over at least a majority of the spectrum between 390nm to 700nm wavelengths, whereby the painted metal is visible through the layer.

3. The vehicle of claim 1, wherein the polymer comprises a molecular structure with Si-O-Si linkages, and the polymer has the general formula [ RSiO [ ]_3/2]_nWherein n represents an integer and R represents hydrogen and/or an organic group bonded to the Si-O-Si linkage.

4. The vehicle of claim 3 wherein R in at least some of the polymers is an organic group and the organic group is bonded to the Si-O-Si linkage via a carbon-silicon bond.

5. The vehicle of claim 1 wherein the passive cooling layer has a thickness of at least 50 μ ι η.

6. The vehicle of claim 5 wherein the passive cooling layer has a thickness of no more than 200 μm.

7. The vehicle of claim 6, wherein a thickness of the passive cooling layer and a concentration of the Si-O-Si connections are such that the layer has an absorption of greater than 99% for light at a wavelength of 10 μm.

8. A vehicle having solar heating mitigation, comprising:

a body having a top; and

a passive cooling layer that covers an outward surface of the roof such that the layer is exposed to light outside the vehicle,

wherein the layer comprises a polymer,

wherein the polymer comprises a molecular structure having Si-O-Si linkages,

wherein the polymer has the general formula [ RSiO_3/2]_nWherein n represents an integer and R represents hydrogen and/or an organic group bonded to Si-O-Si linkage,

wherein R in at least some of the polymers is an organic group, and the organic group is bonded to the Si-O-Si linkage via a carbon-silicon bond.

9. The vehicle of claim 8, wherein the transmission of light through the layer is at least 80% over at least a majority of the spectrum between 390nm and 700nm wavelength.

10. The vehicle of claim 8 wherein the passive cooling layer has a thickness of at least 50 μm and no more than 200 μm.

11. The vehicle of claim 8, wherein a thickness of the passive cooling layer and a concentration of Si-O-Si links are such that the layer has an absorption of greater than 99% for light at a wavelength of 10 μ ι η.

12. A method of manufacturing a vehicle having solar heating mitigation, the method comprising:

the top of the vehicle is coated with a passive cooling layer,

wherein the layer comprises a polymer,

wherein the polymer comprises a molecular structure having Si-O-Si linkages,

wherein the polymer has the general formula [ RSiO_3/2]_nWherein n represents an integer and R represents hydrogen and/or an organic group bonded to Si-O-Si linkage, and

wherein R in at least some of the polymers is an organic group, and the organic group is bonded to the Si-O-Si linkage via a carbon-silicon bond.

13. The method of claim 12, further comprising, after the coating step, heating the polymer to at least 100 ℃ to facilitate bonding of the layer to the top.

14. The method of claim 13, wherein during the heating step, at least some R as an organic group is removed from the polymer while leaving a corresponding Si-O-Si linkage bonded to the top.

15. The method of claim 14, further comprising, after the heating step, cooling the layer to less than 50 ℃, wherein the thickness of the layer after cooling is at least 50 μ ι η and no more than 200 μ ι η.

16. The method of claim 14, wherein the thickness of the passive cooling layer and the concentration of Si-O-Si links are such that the layer has an absorption of greater than 99% for light at a wavelength of 10 μ ι η.

17. The method of claim 16, wherein the polymer is or is a liquid prior to the coating step, and wherein the coating step comprises: the top of the vehicle is sprayed with a passive cooling layer.

18. An article of manufacture, comprising:

the outwardly-facing surface of the article,

a passive cooling layer that covers an outward facing surface of the article such that the layer is exposed to light external to the article,

wherein the layer comprises a polymer,

wherein the polymer comprises a molecular structure having Si-O-Si linkages,

wherein the polymer has the general formula [ RSiO_3/2]_nWherein n represents an integer and R represents hydrogen and/or an organic group bonded to Si-O-Si linkage,

wherein R in at least some of the polymers is an organic group and said organic group is bonded to the Si-O-Si linkage through a carbon-silicon bond, and

wherein the layer has a thickness and a concentration of Si-O-Si connections on the outward facing surface such that the layer has an absorption of light at a wavelength of 10 μm of greater than 80%.

19. The article of claim 18, wherein the passive cooling layer has a thickness of at least 50 μ ι η and no more than 200 μ ι η.

20. The article of claim 18, wherein the thickness of the passive cooling layer and the concentration of its Si-O-Si linkages are such that the layer has an absorption of greater than 99% for light at a wavelength of 10 μ ι η.

Background

Vehicles exposed to sunlight often become hot, which may be undesirable, for example, when the temperature within the vehicle increases or when stresses within the vehicle body are caused by thermal expansion. There is a need for an effective system that mitigates solar heating.

Disclosure of Invention

Applicants have discovered that certain molecular structures as disclosed herein mitigate solar heating by avoiding or dissipating thermal energy in a passive manner without an electromotive force. A layer having this molecular structure (e.g., a film, a thin film coating) can facilitate high emission of thermal energy if applied in sufficient thickness and concentration. Further, applicants have found that the molecular structure may be present in polymeric materials, which may be particularly effective in coating vehicles and other structures for passive cooling.

Aspects of the present disclosure generally relate to a vehicle having solar heating mitigation. The vehicle has a body having a roof, wherein at least a portion of the roof is opaque to sunlight in the visible range. The vehicle also includes a passive cooling layer that overlies the portion of the roof on an outward surface of the roof to expose the layer to light external to the vehicle. The layer comprises (e.g., is formed from, is predominantly) a polymer having a molecular structure with silicon-oxygen-silicon (Si-O-Si) linkages (e.g., bonds, atomic bonds, covalent bonds in the molecule) which applicants believe facilitates the radiative cooling effect. The layer has a thickness and concentration of Si-O-Si bonds such that the layer has an absorption of greater than 80% for light having a wavelength of 10 μm.

Other aspects of the present disclosure generally relate to a vehicle with solar heat mitigation, wherein the vehicle has a body with a top and the vehicle further includes a bagA passive cooling layer covering the outward facing surface of the roof is included such that the layer is exposed to light outside the vehicle. The layer includes a polymer having a molecular structure with Si-O-Si linkages. More specifically, the polymer has the general formula [ RSiO_3/2]_nWherein n represents an integer and R represents hydrogen (H) and/or an organic group bonded to Si-O-Si linkage. R in at least some polymers is an organic group, and the organic group is bonded to the Si-O-Si linkage through a carbon-silicon bond.

Additional aspects of the present disclosure generally relate to methods of manufacturing a vehicle having solar heating mitigation. The method includes the step of coating the top of the vehicle with a passive cooling layer. The layer includes a polymer having a molecular structure with Si-O-Si linkages. Further, the polymer may have the general formula [ RSiO ]_3/2]_n。

Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments as described in the written description and claims hereof, as well as the appended drawings. For example, other aspects of the present disclosure relate to articles other than vehicles having a passive cooling layer as described herein. Further aspects of the present disclosure relate to methods of making such articles. It is to be understood that both the foregoing general description and the following detailed description are exemplary and are intended to provide an overview or framework for understanding the nature and character of the claims.

Drawings

The accompanying drawings are included to provide a further understanding, and are incorporated in and constitute a part of this specification. The drawings in the accompanying drawings illustrate one or more embodiments and, together with the detailed description, serve to explain the principles and operations of the various embodiments. The disclosure, therefore, is best understood from the following detailed description when read in connection with the accompanying drawings, wherein:

FIG. 1 is a perspective view from above of a vehicle having a roof according to an exemplary embodiment.

Fig. 2 is a conceptual sectional view of a portion of the top of fig. 1.

FIG. 3 is a graph of percent emissivity of a material versus wavelength according to an example embodiment.

FIG. 4 is a graph of percent reflectance versus wavelength for a material according to an example embodiment.

FIG. 5 is a digital image of a polymer film according to an exemplary embodiment.

Fig. 6 is a graph of the transmittance of light through the film of fig. 5.

Detailed Description

Before reading the following detailed description and drawings that detail exemplary embodiments, it should be understood that the technology of the present invention is not limited to the details or methodology set forth in the detailed description or illustrated in the drawings. For example, as will be understood by one of skill in the art, features and attributes associated with embodiments shown in one of the figures or described in the text relating to one of the embodiments may also be applicable to other embodiments shown in another of the figures or described elsewhere in the text.

In view of the spectral distribution of blackbody energy, applicants believe that peak energy flux occurs at 2400 to 3600 μm · K, which is the product of absolute temperature and wavelength of light. For room temperature of about 300K, applicants believe that the peak energy occurs at a wavelength of about 8 to 12 μm. Passive cooling of the body by radiation may therefore benefit from a material having a high emissivity in this wavelength region, since emissivity is related to absorption. The applicants have found that silica absorbs strongly in this wavelength region. However, silica has a relatively high reflectance at 10 μm, which is about 30%.

Dilution of the silica in the polymer avoids high reflection by changing the effective refractive index of the silica/polymer composite. In addition, the applicant believes that the dispersion in optical constants produces a strong reflection of the silica, which in turn produces what is known as Florisil at the interface between the silica and the polymerPhenomenon of effect, which resonance phenomenon increases absorption. Such a composite comprising silica is therefore highly emissive and can be used for passive cooling, wherein the silica strongly absorbs light in the 8-12 μm wavelength region and the absorption leads to a high emissivity in this region, which is the desired spectral location for radiative cooling.

Surprisingly, applicants have found that polymers alone can benefit from the above-described radiative cooling effect. General formula [ RSiO ]_3/2]_nSome silicate materials of (a) may be polymers, wherein n represents an integer and R is H or an organic group bound to silica. Such polymers include Si-O-Si linkages in a network interlaced with Si-R, and applicants have found that the Si-O-Si linkages are sufficiently silica-like structures to benefit from the radiative cooling effects described above. More specifically, the applicant believes that the 9 μm absorption in the silica network results from the antisymmetric stretching of the Si-O-Si bond, and therefore, polymeric networks containing these structures exhibit strong absorption characteristics in the same spectral range as silica, and can retain the low reflectivity associated with other polymers, resulting in relatively high emissivity in the 8-12 μm region compared to bulk silica, silicon or other materials.

Referring to fig. 1-2, a vehicle 110 (e.g., car, truck, boat, airplane, trailer) having solar heating mitigation effects, the vehicle 110 includes a body 112 (e.g., cab, cabin, housing, enclosure) of the vehicle having a structure (e.g., wall, roof, covering) in the form of a roof 114. According to an exemplary embodiment, the top 114 is at least partially formed from metal 116 or other structural material (e.g., stucco, slate, composite fibers) that is generally opaque to sunlight in the visible range. In some embodiments, the vehicle 110 also includes a passive cooling layer 118 (e.g., a radiative cooling layer, a thermal energy dissipation layer) that cools the vehicle 110 without an electromotive force. The layer 118 may be overlaid (e.g., indirectly overlaid with one or more intermediate layers, directly bonded, at least covering a majority) with the metal 116 on an outward facing surface of the top 114 and/or other surfaces of the vehicle 110 in fig. 1 to expose the layer 118 to light (e.g., sunlight) external to the vehicle 110, e.g., directly exposed or exposed through a translucent layer overlaid on the layer 118.

According to an exemplary embodiment, layer 118 includes (e.g., is, primarily, substantially) a silicate material such that the material includes an anionic silica compound or group in a compound. In some embodiments, layer 118 includes a molecular structure with Si-O-Si linkages as described above, which can absorb light in the 8-12 μm wavelength region. For example, in some embodiments, layer 118 has a thickness T and a concentration of Si-O-Si junctions such that layer 118 absorbs light at a wavelength of 10 μm by greater than 50%, such as greater than 80%, such as greater than 90%, such as greater than 95%, such as greater than 99%. Since emissivity is absorption related, applicants believe that layer 118 provides passive cooling to underlying body 112.

Materials having Si-O-Si linkages (e.g., silica, silicate materials) may include additional molecular compounds or groups that reduce or control material reflection as described above. Further, applicants have discovered certain polymer compounds that do not require the addition of silica or other silicate materials to the composite. Instead, these polymers themselves have Si-O-Si linkages and relatively low reflectivity, and can provide the benefits of passive cooling without relying on, for example, the fleichg effect. In other words, embodiments disclosed herein include a single polymer that provides the benefits of low reflectivity and high emissivity without the need for combination, mixing, dispersion, etc. of material combinations. Additionally, these polymers can be spray coated and thermally cured, using UV light or otherwise, making them particularly effective and convenient for use in manufacturing and other applications.

In some embodiments, the material of layer 118 includes or is an organic component, e.g., it is an organometallic material, having a chemical bond between carbon and a metal of an organic compound, where organic compounds or groups (e.g., alkyl, aryl, alkoxy) are common to or made by living systems, and are chemical compounds having one or more carbon atoms covalently linked to atoms of other elements, such as hydrogen, oxygen, or nitrogen. In some such embodiments, the material of layer 118 includes or is an organosilicon material and has a chemical bond between carbon and silicon of the organic compound. According to an exemplary embodiment, the material of layer 118 includes Si-O-Si linkages, which may be present in a silicon dioxide or silicate material, for example, wherein the linkages may form rings of Si-O-Si linkages, cage structures of Si-O-Si linkages, ladder structures of Si-O-Si linkages, or more random configurations with Si-O-Si linkages.

For example, in some embodiments, the material of layer 118 includes or is a silicate material and has the general formula [ RSiO_3/2]_nWherein n represents an integer and R represents H and/or an organic group bonded to Si-O-Si linkage, for example, wherein Si-O-Si has a cage structure, a random structure, a ladder structure, or a partial cage structure. In some such embodiments, the R includes or is an organic group, and the organic group is bonded to the Si-O-Si linkage via a carbon-silicon bond. Some examples of such organosilicon materials may include silsesquioxanes, octahedral polysilsesquioxanes, decahedral polysilsesquioxanes, dodecahedral polysilsesquioxanes, cubic silsesquioxanes, imine-silsesquioxanes, polysilsesquioxanes, hydridosiloxanes, organosilsesquioxanes, poly (methylsilsesquioxanes), poly (phenylsilsesquioxanes), poly (hydridosilsesquioxanes), methylsilsesquioxanes, polyhedral oligomeric silsesquioxanes, and the like. In some embodiments, the material of layer 118 includes or is a polymer (i.e., a molecule having a chain of repeating subunits), e.g., having the general formula [ RSiO ] as described herein_3/2]_nThe polymer of (1).

Applicants tested various compositions in accordance with the present disclosure. For example, the weight percent (wt%) of Si and C for each polymer in the table below was determined using a standard inductively coupled plasma optical emission spectroscopy (ICP/OES) analysis test for silicon and a standard Instrument Gas Analysis (IGA) analysis test for carbon.

When these materials are used for layer 118, they may have a sufficient concentration of Si-O-Si linkages to absorb sunlight and corresponding light emission as described herein. If the thickness T is increased, the concentration of Si-O-Si can be decreased. In some embodiments, the thickness of the layer is at least 20 μm, such as at least 50 μm, such as at least 100 μm, such as at least 200 μm, and/or not more than 10mm, such as not more than 5mm, such as not more than 3mm, such as not more than 1mm, such as not more than 500 μm, such as not more than 200 μm. In at least some contemplated embodiments, the thickness T may be less than 20 μm or greater than 10 mm. In some embodiments, the emissivity is at least about 50%, such as at least 70%, such as at least 80%, such as at least about 90%, for wavelengths in the 8 to 12 μm region, such as for a majority of wavelengths therein, such as for at least 90% of wavelengths therein, such as for all wavelengths therein.

Providing passive cooling as disclosed herein and having the general formula [ RSiO_3/2]_nMay be used for layer 118 because the polymer may be in liquid form and sprayed or otherwise relatively easily applied to a surface, such as the top 114 of the vehicle 110. By spraying, the applicant means that the liquid may be driven through a nozzle and formed into small particles or droplets (i.e. atomized), e.g. formed into a mist, and which is blown or otherwise driven by air or another gas to the surface. Some such polymers may be thermosetting or cured by UV light. For example, some manufacturing processes include heating the coating to at least 100 ℃ to facilitate bonding of the layer 118 to the underlying structure, e.g., the metal 116 of the top portion 114. Further, in contemplated embodiments, at least some such polymers may be treated so that the organic groups of the compounds may be burned off or otherwise removed while leaving the Si-O-Si linkages, e.g., to reduce the thickness T of the layer 118 and increase the concentration of the Si-O-Si linkages. Applicants believe that even the organic component of layer 118 is displacedIn addition to or over time, layer 118 may retain the passive cooling benefits.

Applicants have found that without the use of additional materials (e.g., index matching polymers that reduce the reflection of silicon dioxide as described above), it is possible to achieve a polymer having the general formula [ RSiO ]_3/2]_nPassive cooling benefits of the polymeric form of the silicone material of (a). The high emissivity values that occur with such polymers disclosed herein appear to originate from the polymer network of such materials themselves. For example, FIG. 3 shows emissivity data for a 100 μm thick silsesquioxane film. FIG. 4 further demonstrates a compound having the general formula [ RSiO ] as disclosed herein_3/2]_nFig. 4 compares the reflectance of methacryloyl-polyhedral oligomeric silsesquioxanes 210 with the reflectance of bulk high purity fused silica 212 (polymer matrix without index matching). As can be seen, applicants have found that polymers with Si-O-Si linkages have about five times less reflectivity than bulk silica.

Although fig. 1 includes a vehicle 110, layer 118 may be in the form of a film, e.g., a thin film, that may be applied to a variety of surfaces to provide radiant cooling. For example, the layers may be bonded to a metal, such as the metal of the top portion 114, or silicon, or other substance. Some embodiments disclosed herein, for example, a liquid polymer including Si-O-Si linkages can be sprayed onto a surface and cured, for example, by heat or light. Precursor materials to at least some of these materials are commercially available. In some such embodiments, the material may be applied directly to the surface of the article, e.g., the surface of a vehicle, roof, structure, etc., and cured. Further, the material may be used to form a layer similar to layer 118 on an article of manufacture or an already manufactured and/or configured article, for example, on a roof of a building, a sink, a storage unit, a solar cell, an equipment enclosure, etc., that may benefit from passive cooling.

Figure 5 shows a free standing photopolymerizable silsesquioxane polymer 310 with a thickness of 100 μm. To produce the film, the Applicant turned the nailAdding a photoinitiator into acrylate (or acrylate) octahedral polysilsesquioxane, wherein the silsesquioxane is in the [ RSiO ] state_3/2]_nThe corners of the molecular cage have organic methacrylate groups and applicants next photopolymerize this material to form a crosslinked polysilsesquioxane, as shown in FIG. 5. Alternatively, these formulations can be mixed with a solvent for application by spraying, dipping, aerosol spraying, roll coating, knife coating, or other methods, followed by uv or thermal curing.

As can be seen in fig. 5, the polymer film is relatively transparent. Fig. 6 shows the percent transmission of light through the polymer film of fig. 5 over a portion of the electromagnetic spectrum. The transmission of light through the film is at least 50%, such as at least 80%, such as at least 90%, over at least some of the visible spectrum, such as at least a majority of the spectrum between wavelengths of 390nm and 700nm, such as the entire spectrum between wavelengths of 390nm and 700 nm.

Applicants tested the percent emissivity of a similarly thin coating of a phenyl silsesquioxane dimethylsiloxane copolymer and found similar performance and advantages over high purity fused silica, wherein the emissivity is at least 80%, such as at least 85%, such as at least 90%, for at least some light in the 8 to 12 μm wavelength range, such as at least a majority of light in the 8 to 12 μm wavelength range, such as for at least 80% and at least 85% emissivity, for all light in the 8 to 12 μm wavelength range. Applicants have also found that, through empirical experimentation, increasing the thickness of layer 118 above 100 μm increases the emissivity in at least some of the 8 to 12 μm wavelength range.

Thus, films of polymers having Si-O-Si linkages as disclosed herein may be used with articles that may benefit from or require transmission of some or all of the visible spectrum of light therethrough, such as windows (e.g., windshields, skylights), transparent housings (e.g., greenhouses), photovoltaic cells, and the like. Articles comprising paint, text, or other decoration may benefit from a passive cooling layer as disclosed herein that covers the decoration, but through which the decoration is still visible. In addition to vehicles, articles such as outdoor seats (e.g., stadium seats, park chairs), armrests, barefoot walkways, and the like may be uncomfortable to the user when exposed to excessive solar heat, but these articles may also benefit from being coated with the passive cooling layer disclosed herein.

The construction and arrangement of the methods and products as shown in the various exemplary embodiments are illustrative only. Although only a few embodiments have been described in detail in this disclosure, many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations) without materially departing from the novel teachings and advantages of the subject matter described herein. Some elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be interchanged or otherwise varied, and the nature or number of discrete elements or positions may be changed or altered. The order or sequence of any process, logic algorithm, or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes and omissions may also be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the technical scope of the present invention.