SPLIT BAND-BASED REVERSELY DIFFERENT LIGHT PATH SOLAR THERMAL COMPOUND DEVICE

Abstract

The present application provides a split band-based reversely different light path (RDLP) solar thermal compound device. The device includes, but not limited to: a split band RDLP component, a mid-infrared radiative cooler, and a sunlight converter. The split band RDLP component is disposed above the mid-infrared radiative cooler and the sunlight converter, and is suspended by using a support, so that the split band RDLP component is kept from contacting with the components below, to prevent heat conduction. A cavity is provided between the mid-infrared radiative cooler and the sunlight converter below. The cavity is provided to prevent heat conduction between the two. Such a design implements the simultaneous and efficient use of a solar heat source and a radiative cooling source.

Claims

1. A split band-based reversely different light path (RDLP) solar thermal compound device, comprising: a split band RDLP component, a mid-infrared radiative cooler, and a sunlight converter, wherein the split band RDLP component is disposed above the mid-infrared radiative cooler and the sunlight converter, and is configured to converge and focus incident sunlight band electromagnetic waves and converge and focus mid-infrared band electromagnetic waves emitted by the mid-infrared radiative cooler, and a cavity is provided between the mid-infrared radiative cooler and the sunlight converter.

2. The split band-based RDLP solar thermal compound device according to claim 1, further comprising: a support, the support being used for fixing the split band RDLP component, and keeping the split band RDLP component from contacting with the mid-infrared radiative cooler and the sunlight converter.

3. The split band-based RDLP solar thermal compound device according to claim 1, wherein the split band RDLP component has a spherical shape, or, the split band RDLP component has a nonspherical semi-enclosed structure.

4. The split band-based RDLP solar thermal compound device according to claim 1, wherein an overall area of the sunlight converter is smaller than an area of the mid-infrared radiative cooler, and the sunlight converter is disposed in a central region of the mid-infrared radiative cooler.

5. The split band-based RDLP solar thermal compound device according to claim 1, wherein the split band RDLP component comprises two optical surfaces on an inner side and an outer side, and a light way of sunlight being propagated from the outer side to the inner side is different from a light way of infrared light being propagated from the inner side to the outer side.

6. The split band-based RDLP solar thermal compound device according to claim 1, wherein a material of the split band RDLP component is selected from the group consisting of zinc selenide, polyethylene, hafnium oxide, barium fluoride, and any combination thereof.

7. The split band-based RDLP solar thermal compound device according to claim 1, wherein the split band RDLP component is selected from a conventional lens, a Fresnel lens or a superlens with a micro-nano structure.

8. The split band-based RDLP solar thermal compound device according to claim 7, wherein the split band RDLP component has a certain transmittance in a full band, and has a focal power in both a solar band and a mid-infrared band.

9. The split band-based RDLP solar thermal compound device according to claim 7, wherein the superlens comprises a super surface with the micro-nano structure, and the super surface comprises: a base, wherein an upper surface is provided on one side of the base, and the upper surface is configured to converge and focus the incident sunlight band electromagnetic waves; and a lower surface is provided on the other side opposite to the upper surface, and the lower surface is configured to converge and focus the mid-infrared band electromagnetic waves emitted by the mid-infrared radiative cooler.

10. The split band-based RDLP solar thermal compound device according to claim 1, wherein the sunlight converter is a solar cell or a solar thermal collector.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG. 1 is a schematic diagram of a split band-based RDLP solar thermal compound device according to an embodiment of the present application;

[0035] FIG. 2 is a schematic diagram of a solar thermal compound device using an infrared lens according to an embodiment of the present application;

[0036] FIG. 3 is a schematic diagram of a solar thermal compound device using a super surface structure according to an embodiment of the present application;

[0037] FIG. 4 is a schematic diagram of a super surface structure according to an embodiment of the present application; and

[0038] FIG. 5 is a schematic cross-sectional view of a bottom of a solar thermal compound device according to an embodiment of the present application.

[0039] In the accompanying drawings: 1. split band RDLP component, 2. mid-infrared radiative cooler, 3. sunlight converter, 4. cavity, 5. mid-infrared electromagnetic wave emitted by the mid-infrared radiative cooler, 6. electromagnetic wave in a solar band, 7. infrared lens, 8. support, 9. super surface, 10. upper surface of the super surface, 11. base, and 12. lower surface of the super surface.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] The above solutions are further described below with reference to specific embodiments. It should be understood that these embodiments are intended to describe the present application and are not limited to limit the scope of the present application. The implementation conditions used in the embodiments can be further adjusted as in the specific manufacturer's conditions, and the implementation conditions not indicated are usually those used in routine experiments.

[0041] The present application provides a split band-based RDLP solar thermal compound device. The device includes: a split band RDLP component, a mid-infrared radiative cooler, and a sunlight converter. The split band RDLP component is disposed above the mid-infrared radiative cooler and the sunlight converter, and is suspended by using a support, so that the split band RDLP component is kept from contacting with the components below, to prevent heat conduction. A cavity is provided between the mid-infrared radiative cooler and the sunlight converter below to prevent heat conduction between the two. The split band RDLP component may have a spherical shape, or may be designed into a nonspherical semi-enclosed structure as required. The split band RDLP component includes two optical surfaces on an inner side and an outer side. A light way of sunlight being propagated from the outer side to the inner side is different from a light way of infrared light being propagated from the inner side to the outer side. Such a component is referred to as a split band RDLP component. The material of the component may be selected from the group consisting of zinc selenide, polyethylene, hafnium oxide, barium fluoride, and any combination thereof. The type of the component may be a conventional lens, a Fresnel lens or a superlens with a micro-nano structure, and may have a certain transmittance in a full band and have a focal power in two bands (a solar band and a mid-infrared band).

[0042] The sunlight converter is a component converting solar energy into thermal energy or electrical energy, and is mainly a solar cell or a solar thermal collector.

[0043] The sunlight converter is disposed at the central of the mid-infrared radiative cooler. The area of the sunlight converter needs to cover a sunlight focal point of the split band RDLP component, and has a relatively small overall area. The mid-infrared radiative cooler generally occupies a relatively large area. As a component converting thermal energy into infrared light, the mid-infrared radiative cooler radiates heat thereof to outer space in the form of electromagnetic waves through an atmospheric transparency window, to implement that the temperature of the mid-infrared radiative cooler is lower than ambient temperature.

[0044] The split band RDLP component with the semi-enclosed structure completely covers the region above the solar thermal combination components, and is fixed thereon by a support or in another manner with a small gap therebetween to prevent direct heat conduction. The component has an important characteristic of having a focal power for electromagnetic waves in a mid-infrared band and a solar band and having a certain transmittance, so that the electromagnetic waves in the two bands can penetrate the material. Parallel incident sunlight passes through the split band RDLP component to focus on the sunlight converter, to converge original sunlight to focus and irradiate a relatively small region of the solar conversion component, and convert solar energy into energy in another form for output. Because the mid-infrared radiative cooler at the periphery has a relatively high mid-infrared emissivity, infrared radiation emitted by the mid-infrared radiative cooler passes through the split band RDLP component to be collimated and converged in a very small solid angle, so that all thermal radiation can pass through an atmospheric window smoothly, thereby eventually enhancing the effect of radiative cooling.

[0045] It needs to specifically noted that because sunlight passes through the split band RDLP component to completely focus in the region of the sunlight converter, there is basically no solar energy in the mid-infrared radiative cooler. Therefore, the design requirement of low absorptivity of the mid-infrared radiative cooler in the solar band can be greatly simplified. Because it is not necessary to shield against solar energy for the mid-infrared radiative cooler and the split band RDLP component has already transferred original solar energy, it is only necessary to achieve the objective of high emissivity in an infrared atmospheric window band. This greatly simplifies the manufacturing of the mid-infrared radiative cooler, and the effect of radiative cooling is not reduced.

[0046] Next, the solar thermal compound device provided in the embodiments of the present application is described with reference to the accompanying drawings.

[0047] FIG. 1 is a schematic diagram of a split band-based RDLP solar thermal compound device.

[0048] The device includes: [0049] a split band RDLP component 1, a mid-infrared radiative cooler 2, and a sunlight converter 3.

[0050] The split band RDLP component 1 is disposed above the mid-infrared radiative cooler 2 and the sunlight converter 3, and is suspended by using a support 8, so that the split band RDLP component is kept from contacting with the components below, to prevent heat conduction. A cavity 4 is provided between the mid-infrared radiative cooler 2 and the sunlight converter 3 below the split band RDLP component 1. The cavity 4 prevents heat conduction between the mid-infrared radiative cooler 2 and the sunlight converter 3. In this implementation, the support 8 is kept from contacting with the mid-infrared radiative cooler 2 and prevents heat conduction.

[0051] As a variant of the foregoing implementation, angle regulation in two bands is implemented by using an infrared lens 7.

[0052] After the compound device is placed on an object that requires temperature reduction, parallel incident electromagnetic waves 6 in the solar band from outside irradiate the device. Light in the solar band is focused into a relatively small range by using the focusing and convergence capability of the lens 2, that is, is focused at the position of the mid-infrared radiative cooler 2 in the lower components. This part of sunlight energy can be used for thermal energy collection and supply, and may be used for electrical energy collection by using a solar cell panel.

[0053] After the thermal energy of the object that requires temperature reduction is transferred to the mid-infrared radiative cooler 2, because the mid-infrared radiative cooler has a strong mid-infrared emission capability, the thermal energy is converted into mid-infrared electromagnetic waves and transferred to outer space through an atmospheric window. In this implementation, the lens is made of an infrared material and can converge emission angles of anisotropic radiators to some extent. For the angle convergence, the mid-infrared electromagnetic waves may be propagated to the outer space through the atmospheric window in the form of perpendicular incidence, to reduce the blockage by cloud layers, thereby maximizing the efficiency of radiative cooling. Distances from the infrared lens 7 to the mid-infrared radiative cooler 2 and the cavity 4 below are dependent on the optimal focal length of the lens. The distance between the mid-infrared radiative cooler 2 and the cavity 4 is to avoid contact and prevent heat conduction.

[0054] A variant of the implementation in FIG. 1 is shown in FIG. 3 and FIG. 4. In the split band-based RDLP solar thermal compound device, a super surface 9 is used in place of the infrared lens 7. In the scheme in FIG. 1, the infrared lens is used to converge electromagnetic waves in two bands. However, because the ranges of the bands are relatively far from each other, it is very difficult to use a conventional infrared lens to adequately regulate the two bands. Therefore, a superlens (the super surface 9) is used to replace the infrared lens 7. The superlens has a super surface with a micro-nano structure. The super surface is a relatively flexible electromagnetic wave regulation measure with a high degree of design freedom, thereby resolving the problem that it is difficult to use a conventional lens to respectively perform convergence in two bands. An upper surface portion of the super surface converges and focuses the incident sunlight band electromagnetic waves. A lower surface portion of the super surface converges and focuses the mid-infrared band electromagnetic waves emitted by the mid-infrared radiative cooler. In this way, the superlens is used to implement the function of beam focusing and at the same time satisfy the effect of bidirectional two-band light way convergence.

[0055] The structure of the (two-sided) super surface is described below with reference to FIG. 4.

[0056] The super surface includes: a base 11. An upper surface 10 is configured to on one side of the base 11, and a lower surface 12 is provided on the opposite other side. In the structure, sunlight may first pass through the upper surface 10 of the super surface from above to the structure below. The sunlight may be focused on the sunlight converter below by regulating the phase of the solar band. Mid-infrared electromagnetic waves emitted by the mid-infrared radiative cooler below first pass through the lower surface of the super surface, and achieves the effect of converging emission angles through phase regulation.

[0057] As shown in FIG. 5, the support 8 supports the split band RDLP component for suspension thereof. The cavity 4 is provided between the mid-infrared radiative cooler 2 and the sunlight converter 3 to prevent heat conduction between the two.

[0058] The foregoing embodiments are only used to describe the technical concept and characteristics of the present application, and are intended to enable a person skilled in the art to understand the content of the present application and achieve implementation, but shall not be used to limit the protection scope of the present application. Any equivalent variations or modifications made according to the spirit and essence of the present application shall fall within the protection scope of the present application.