Photovoltaic receiver with phase-change material heat sink

Abstract

A photovoltaic (PV) receiver for power beaming and an associated heat dissipation method are disclosed. The PV receiver can include a PV cell array configured to receive a transmission beam having a non-uniform beam irradiance profile and convert the transmission beam into electrical power, with the non-uniform beam irradiance profile resulting in non-uniform heating of the PV cell array. The PV receiver can also include a heat sink configured to absorb and dissipate heat generated by the PV cell array. The heat sink can include a phase- change material (PCM) arrangement having a non-uniform heat dissipation profile configured to counteract the non-uniform heating of the PV cell array. The PCM arrangement can be provided with a plurality of PCM regions characterized by different values of a physical property, such as PCM composition or density, affecting heat dissipation to define the non-uniform heat dissipation profile of the PCM arrangement.

Description

PHOTOVOLTAIC RECEIVER WITH PHASE-CHANGE MATERIAL HEAT SINKRELATED PATENT APPLICATION

[0001] The present application claims priority to U.S. Provisional Patent Application No. 63 / 580,597 filed on September 5, 2023, the disclosure of which is incorporated herein by reference in its entirety.TECHNICAL FIELD

[0002] The technical field pertains to photovoltaic (PV) receivers for power beaming, and specifically to a PV receiver with a phase-change material (PCM) heat sink configured to reduce the effect of non-uniform beam heating on receiver performanceBACKGROUND

[0003] Power beaming, a form of point-to-point wireless power transfer, employs directed beams of electromagnetic radiation, such as laser and microwave beams, to transmit electrical energy from a transmitter to a receiver, often over considerable distances (e.g., hundreds or even thousands of kilometers). Laser power beaming, in particular, offers the potential for high-intensity, low-divergence, long-range transmission, with applications spanning various fields and industries, both on Earth and in space. In these systems, a laser transmitter emits laser radiation toward a photovoltaic (PV) receiver, which is configured to capture the laser radiation and convert it into electricity. Despite ongoing advancements, numerous challenges persist in the field of power beaming.SUMMARY

[0004] The present description relates to a PV receiver for power beaming, including a PV cell array and a phase-change material (PCM) heat sink. The PCM heat sink features a non-uniform heat dissipation profile configured to counteract the effects of non-uniform heating of the PV cell array caused by non-uniform illumination.

[0005] In accordance with an aspect, there is provided a photovoltaic (PV) receiver, including: a PV cell array configured to receive a transmission beam having a non-uniform beam irradiance profile and convert the transmission beam into electrical power, the non-uniform beam irradiance profile resulting in non-uniform heating of the PV cell array; and a heat sink configured to absorb and dissipate heat generated by the PV cell array, the heat sink including a phase-change material (PCM) arrangement having a non-uniform heat dissipation profile configured to counteract the non-uniform heating of the PV cell array.

[0006] In some embodiments, the PCM arrangement includes a plurality of PCM regions characterized by different values of a physical property affecting heat dissipation, the plurality of PCM regions defining the non- uniform heat dissipation profile of the PCM arrangement. In some embodiments, the physical property affectingheat dissipation includes thermal conductivity, specific heat capacity, volumetric heat capacity, specific heat of fusion, phase transition temperature, or any combination thereof. In some embodiments, the PCM regions differ from one another in PCM composition to provide the different values of the physical property affecting heat dissipation. In some embodiments, the PCM regions differ from one another in PCM density to provide the different values of the physical property affecting heat dissipation.

[0007] In some embodiments, the non-uniform beam irradiance profile has a radially decreasing intensity distribution with a stronger intensity illuminating a central portion of the PV cell array and a weaker intensity illuminating a peripheral portion of the PV cell array disposed around the central portion; the plurality of PCM regions includes a first PCM region located under the central portion and a second PCM region located under the peripheral portion; and the non-uniform heat dissipation profile of the PCM arrangement has a higher heat dissipation efficiency in the first PCM region is than in the second PCM region. In some embodiments, the non-uniform beam irradiance profile has a Gaussian distribution. In some embodiments, the first PCM region has a circular shape and the second PCM region has an annular shape.

[0008] In some embodiments, the non-uniform beam irradiance profile has a first intensity level across a first portion of the PV cell array and a second intensity level across a second portion of the PV cell array, with the first intensity level being higher than the second intensity level; the plurality of PCM regions includes a first PCM region located under the first portion and a second PCM region located under the second portion; and the non-uniform heat dissipation profile of the PCM arrangement has a higher heat dissipation efficiency in the first PCM region than in the second PCM region.

[0009] In some embodiments, the first PCM region has a first PCM composition and the second PCM region has a second PCM composition different from the first PCM composition. In some embodiments, the first PCM region has a first PCM density and the second PCM region has a second PCM density less than the first PCM density. In some embodiments, the first PCM region includes at least one first PCM compartment, each first PCM compartment configured to receive a respective amount of PCM, and the second PCM region includes at least one second PCM compartment, each second PCM compartment configured to receive a respective amount of PCM.

[0010] In some embodiments, the PCM arrangement is configured to undergo reversible solid-to-liquid transitions.

[0011] In some embodiments, the heat sink further includes heat pipes in thermal contact with the PCM arrangement and configured to provide further dissipation of the heat generated by the PV cell array.

[0012] In some embodiments, the transmission beam is transmitted from a beam transmitter, the beam transmitter and the PV receiver forming a power beaming system. In some embodiments, the transmission beam is a laser beam. In some embodiments, the transmission beam includes sunlight.

[0013] In accordance with another aspect, there is provided a power beaming system including: a beam transmitter configured to transmit a transmission beam; and a PV receiver as disclosed herein, wherein the PV receiver is configured to receive the transmission beam from the beam transmitter and convert the transmission beam into electrical power.

[0014] In accordance with another aspect, there is provided method for heat dissipation in PV power generation, the method including: receiving a transmission beam on a PV cell array to convert the transmission beam into electrical power, the transmission beam having a non-uniform beam irradiance profile that causes non-uniform heating of the PV cell array; and disposing a heat sink in thermal contact with the PV cell array to absorb and dissipate heat generated by the PV cell array over time under illumination by the transmission beam, the heat sink including a phasechange material (PCM) arrangement with a non-uniform heat dissipation profile configured to counteract the non-uniform heating of the PV cell array.

[0015] In some embodiments, the method further includes: providing the PCM arrangement with a plurality of PCM regions characterized by different values of a physical property affecting heat dissipation, the plurality of PCM regions defining the non-uniform heat dissipation profile of the PCM arrangement. In some embodiments, providing the PCM arrangement with the plurality of PCM regions includes: selecting the physical property affecting heat dissipation from thermal conductivity, specific heat capacity, volumetric heat capacity, specific heat of fusion, phase transition temperature, or any combination thereof.

[0016] In some embodiments, providing the PCM arrangement with the plurality of PCM regions includes: configuring the PCM regions to differ from one another in PCM composition to provide the different values of the physical property affecting heat dissipation. In some embodiments, providing the PCM arrangement with a plurality of PCM regions includes: configuring the PCM regions to differ from one another in PCM density to provide the different values of the physical property affecting heat dissipation.

[0017] In some embodiments, the non-uniform beam irradiance profile has a radially decreasing intensity distribution with a stronger intensity illuminating a central portion of the PV cell array and a weaker intensity illuminating a peripheral portion of the PV cell array disposed around the central portion; and providing the PCM arrangement with a plurality of PCM region includes: providing a first PCM region located under the central portion and a second PCM region located under the peripheral portion; and configuring the non-uniformheat dissipation profile of the PCM arrangement to have a higher heat dissipation efficiency in the first PCM region is than in the second PCM region. In some embodiments, the non-uniform beam irradiance profile has a Gaussian distribution. In some embodiments, providing the first PCM region and the second PCM region includes: providing the first PCM region with a circular shape and the second PCM region with an annular shape.

[0018] In some embodiments, the non-uniform beam irradiance profile has a first intensity level across a first portion of the PV cell array and a second intensity level across a second portion of the PV cell array, with the first intensity level being higher than the second intensity level; and providing the PCM arrangement with a plurality of PCM region includes: providing a first PCM region located under the first portion and a second PCM region located under the second portion; and providing the non-uniform heat dissipation profile of the PCM arrangement with a higher heat dissipation efficiency in the first PCM region is than in the second PCM region.

[0019] In some embodiments, providing the first PCM region and the second PCM region includes: providing the first PCM region with a first PCM composition and the second PCM region with a second PCM composition different from the first PCM composition. In some embodiments, providing the first PCM region and the second PCM region includes: providing the first PCM region with a first PCM density and the second PCM region with a second PCM density less than the first PCM density. In some embodiments, providing the first PCM region and the second PCM region includes: providing the first PCM region with at least one first PCM compartment, each first PCM compartment configured to receive a respective amount of PCM; and providing the second PCM region with at least one second PCM compartment, each second PCM compartment configured to receive a respective amount of PCM.

[0020] In some embodiments, the PCM arrangement is configured to undergo reversible solid-to-liquid transitions.

[0021] In some embodiments, the method further includes: providing the heat sink with heat pipes in thermal contact with the PCM arrangement and configured to provide further dissipation of the heat generated by the PV cell array.

[0022] In some embodiments, the method further includes receiving the transmission beam from a beam transmitter, the beam transmitter and the PV receiver forming a power beaming system. In some embodiments, transmission beam is a laser beam. In some embodiments, the transmission beam includes sunlight.

[0023] In accordance with another aspect, there is provided a PV receiver, including: a PV cell array configured to receive a transmission beam having a non-uniform beam irradiance profile and convert the transmission beam into electrical power, the non-uniform beam irradiance profile resulting in non-uniform heating of the PV cell array; and a heat sink configured to absorb and dissipate heat generated by the PV cell array, the heat sink including a phase-change material (PCM) arrangement having a non-uniform heat dissipation profile configured to counteract the non-uniform heating of the PV cell array.

[0024] In accordance with another aspect, there is provided a method for heat dissipation in photovoltaic (PV) power generation, the method including: receiving, on a PV cell array, a transmission beam to convert the transmission beam into electrical power, the transmission beam having a non-uniform beam irradiance profile that causes non-uniform heating of the PV cell array; and disposing a heat sink in thermal contact with the PV cell array to absorb and dissipate heat generated by the PV cell array over time under illumination by the transmission beam, the heat sink including a phasechange material (PCM) arrangement having a non-uniform heat dissipation profile configured to counteract the non-uniform heating of the PV cell array.

[0025] Other method and process steps may be performed prior, during or after the steps described herein. The order of one or more steps may also differ, and some of the steps may be omitted, repeated, and / or combined, as the case may be. It is also to be noted that some steps may be performed using various analysis and processing techniques, which may be implemented in hardware, software, firmware, or any combination thereof.

[0026] Other objects, features, and advantages of the present description will become more apparent upon reading of the following non-restrictive description of specific embodiments thereof, given by way of example only with reference to the appended drawings. Although specific features described in the above summary and in the detailed description below may be described with respect to specific embodiments or aspects, it should be noted that these specific features may be combined with one another unless stated otherwise.BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Fig. 1 is a schematic representation of a power beaming system including a beam transmitter and a PV receiver, in accordance with an embodiment.

[0028] Fig. 2 is a schematic representation of a heat sink with a PCM arrangement for use in PV receiver, in accordance with another embodiment.

[0029] Fig. 3 is a schematic representation of a heat sink with a PCM arrangement for use in PV receiver, in accordance with another embodiment.

[0030] Fig. 4 is a schematic representation of a heat sink with a PCM arrangement for use in PV receiver, in accordance with another embodiment.

[0031] Fig. 5 is a schematic representation of a heat sink with a PCM arrangement for use in PV receiver, in accordance with another embodiment.

[0032] Fig. 6 is a flow diagram of a method for heat dissipation in PV power generation, in accordance with another embodiment.DETAILED DESCRIPTION

[0033] The present description pertains to thermal management techniques for heat dissipation in photovoltaic (PV) receivers exposed to non-uniform illumination in power beaming and other applications. These techniques are applicable across a wide range of fields and industries where enhanced heat dissipation is desired or necessary. Non-limiting examples include space-based solar power; space and astronomical body exploration and mining; Earth-orbit applications; telecommunications; land and aerial transportation; climate and environmental monitoring; remote area power supply; post-disaster aid and recovery; and energy decarbonization. The present techniques can be implemented in various environments and settings, including on Earth (encompassing ground, marine, and aerial applications), in space, or on other astronomical bodies such as the Moon or other planets.

[0034] Various aspects and implementations of the present techniques are described below with reference to the accompanying figures.

[0035] Referring to Fig. 1, a PV receiver 100 configured to use in power beaming applications is depicted, in accordance with an embodiment. The PV receiver 100 generally includes a PV cell array 102 and a heat sink 104 that is in thermal contact with the PV cell array 102. The heat sink 104 is configured to absorb heat from the PV cell array 102 and dissipate the absorbed heat to the surrounding environment. The PV receiver 100 operates in conjunction with a beam transmitter 106, which is configured to emit a transmission beam 108 with a non-uniform beam irradiance profile and direct the transmission beam 108 onto the PV cell array 102. Together, the beam transmitter 106 and the PV receiver 100 form a power beaming system 110. The PV cell array 102 is configured to receive the transmission beam 108 and convert it into electrical power. However, the non-uniform beam irradiance profile of the transmission beam 108 causes uneven heating of the PV cell array 102, leading to a non-uniform temperature distribution across the PV cell array 102. To address this, the heat sink 104 includes a phase-change material (PCM) arrangement 112 with a non-uniform heat dissipation profile, which is configured to counteract the effect of the non-uniform heating of the PV cell array 102 under non-uniform illumination. PCMs are substances that releases or absorbs latent heat energy at a steady or near-constant temperature during phase transitions, thereby providing heating or cooling as needed.

[0036] The term “counteract” as used herein refers to the function of the PCM arrangement 112 in the heat sink 104, which is designed to at least partially reduce temperature non-uniformities across the PV cell array 102 that arise due to non-uniform beam -induced heating during power beaming. This term does not necessarily imply complete suppression of temperature non-uniformities but encompass a range of where such non-uniformities are mitigated, adjusted, offset, compensated for, attenuated, or otherwise reduced to an appropriate or sufficient degree. The acceptable level of reduction depends on the specific application. For example, in some embodiments, temperature non-uniformities may be considered “counteracted” if they do not significantly or adversely affect the operation of the PV receiver 100.

[0037] The PV receiver 100 can be employed in various power beaming configurations, both on Earth and beyond. Non-limiting examples of such configurations include Earth-to-Earth, space-to-Earth, Earth-to-space, space -to-space, Moon-to-Moon, space-to-Moon, and Moon-to-space power beaming. In some embodiments, the PV receiver 100 can be separated from the beam transmitter 106 by a beam transmission distance ranging from about one or a few hundred meters to about one or a few hundred kilometers, for example, from about 40 km to about 200 km, although distances outside these ranges may be used in other embodiments. Additionally, either or both of the PV receiver 100 and the beam transmitter 106 may be configured for spacebome operations or, alternatively, for landbome, waterborne, or airborne operations on the Earth, the Moon, another planet, or another astronomical body. For example, in solar-based solar power applications, the beam transmitter 106 may be positioned in space (e.g., on a satellite), while the PV receiver 100 may be located on Earth (at a ground-based site).

[0038] In some embodiments, the PV receiver 100 and the beam transmitter 106 may each be mounted, integrated, or otherwise provided on a respective transmitter and receiver platform (not shown in Fig. 1). The term “platform” broadly encompasses any suitable type of landbome, waterborne, airborne, or spacebome devices, vehicles, infrastructures, or equipment — whether manned or unmanned, mobile or fixed — on which the PV receiver 100 and the beam transmitter 106 may be installed during a power beaming operation. Nonlimiting examples of platforms that can be used in space-based power beaming applications include launchers, landers, rovers, satellites, space probes, spaceplanes, space capsules, and space stations.

[0039] The structure, configuration, and operation of these and other possible components of, or coupled to, the PV receiver 100 are detailed below. It is appreciated that Fig. 1 is a schematic representation that aims to illustrate various components and features of the PV receiver 100 and its environment, such that additional components and features that may be useful or beneficial for its practical operation might not be depicted. Nonlimiting examples of such additional features and components include optical components such as lenses, mirrors, and optical filters.

[0040] The beam transmiter 106 can include a light source 114 configured to generate the transmission beam 108, and transmiter conditioning optics 116 configured to condition the transmission beam 108 before it exits the beam transmiter 106.

[0041] The terms “light” and “optical”, along with their variants and derivatives, encompass radiation across any appropriate region of the electromagnetic spectrum. This includes not only visible light but also extends to invisible regions such as the microwave (MW), terahertz (THz), infrared (IR), and ultraviolet (UV) spectral bands.

[0042] The light source 114 can be any device or combination of devices capable of generating the transmission beam 108 with characteristics suitable for power beaming in accordance with the present techniques, including a non-uniform irradiance profile. In some embodiments, the light source 114 is a laser source configured to emit the transmission beam 108 as a laser beam. For example, the light source 114 may be a high-power, single-mode laser source configured to emit the transmission beam 108 as a collimated (e.g., nearly diffraction limited) and narrowband (e.g., quasi-monochromatic) laser beam that can travel over long distances due to its low beam divergence. Non-limiting examples of laser sources for power beaming applications include solid-state lasers, including bulk crystal lasers and fiber lasers; semiconductor lasers, including laser diodes; gas lasers, including carbon dioxide lasers and chemical oxygen-iodine lasers dye lasers. However, non-laser light sources such as light-emiting diodes (LEDs) may also be used in other embodiments. Depending on the specific application, the light source 114 may be operated in a continuous-wave or pulsed regime, and may or may not be modulated. The selection of the light source 114 may be based on various factors, including the operation wavelength; the beam irradiance; the spatial, temporal, and spectral beam profiles; the beam quality and divergence; the degree of coherence; the compactness, reliably, and ruggedness; and for pulsed light sources, pulse characteristics such as peak power, repetition rate, duration, and temporal shape. The theory, instrumentation, and operation of beam transmiters used in conventional power beaming applications are generally known in the art and need not be described in detail herein, except as necessary to understand the present techniques.

[0043] In some embodiments, the light source 114 is configured to emit the transmission beam 108 with a beam wavelength(e.g., a center wavelength) within a waveband ranging from about 400 nm to about 2500 nm, encompassing the visible or near-IR portions of the electromagnetic spectrum. For example, in some cases, the beam wavelengthmay range from about 500 nm to about 1500 nm (e.g., from about 1000 nm to about 1110 nm), or from about 1900 nm to about 2100 nm. However, the present techniques can operate outside these ranges, including at shorter wavelengths (e.g., UV power beaming) or longer wavelengths (e.g., mid-IR, far-IR, THz, and MW power beaming). Furthermore, all descriptions provided herein as a function of wavelength could also be formulated as a function of frequency, wave number, energy, or other pertinent spectral parameters.

[0044] In some embodiments, the light source 114 is configured to emit the transmission beam 108 with any suitable non-uniform irradiance profile, for example, with stronger intensity at the beam center and radially decreasing intensity away from the beam center, such as a Gaussian or quasi-Gaussian profile. However, other non-uniform irradiance profiles can be used in other embodiments, including non-Gaussian irradiance profiles (e.g., flat-top profiles).

[0045] The transmitter conditioning optics 116 may include any optical component or combination of optical components capable of shaping, focusing, concentrating, filtering, steering, collimating, expanding, or otherwise acting on the transmission beam 108 to achieve accurate, efficient, and safe beamed power transfer. Non-limiting examples of optical components for the transmitter conditioning optics 116 include lens, prisms, mirrors, diffraction gratings, and optical filters. Some of these optical components may function integrally, such as beam expanders (e.g., telescopes) or beam steering or pointing devices. The theory, instrumentation, and operation of transmitter conditioning optics used in conventional power beaming applications are generally known in the art and need not be described in detail herein, except as necessary to understand the present techniques.

[0046] Referring still to Fig. 1, the PV cell array 102 can be based on any suitable PV cell technology. The PV cells can have various sizes, shapes, compositions, structures, and configurations (e.g., fill factor, cell packing density, array geometry), as well as electrical and thermal characteristics and circuitry arrangements. In some embodiments, the PV cell array 102 may be designed for terrestrial use, while in other embodiments, the PV cell array 102 may be configured for use in space or other extraterrestrial environments. The PV cell array 102 may include single-junction PV cells in certain embodiments, or multi -junction cells in others, such as vertical multi-junction (VMJ) cells. Multi-junction PV cells include stacked layers of PV materials, with each layer having a different bandgap energy tailored for opto-electronic conversion of photons in different energy ranges.

[0047] The PV cells may be composed of various PV materials, including both direct-bandgap and indirect- bandgap semiconductor materials capable of absorbing light and convert it into electrical power. Non-limiting examples of possible PV materials include silicon (e.g., monocry stalline, polycrystalline, or amorphous silicon), germanium, III-V semiconductors and related alloys (e.g., GaAs, InP, InGaAs, InGaP, GalnP, InAlGaAs, InGaAsP, GaAlInAsSb), thin-film PV materials (e.g., CdTe, CIGS), and organic PV materials. The theory, instrumentation, and operation of PV cellsAsare generally known in the art and need not be described in detail herein, except as necessary to understand the present techniques.

[0048] The PV receiver 100 may also include receiver conditioning optics 118 configured to collect, shape, concentrate, focus, direct, homogenize, or otherwise act on the transmission beam 108 before it reaches the PV cells. Non-limiting examples of optical components for the receiver conditioning optics 118 include lens,prisms, mirrors, diffraction gratings, and optical filters. The theory, instrumentation, and operation of conventional receiver conditioning optics used in power beaming applications are generally known in the art and need not be described in detail herein, except as necessary to understand the present techniques.

[0049] In solar power applications, whether spaced-based or ground-based, a PV cell array is typically illuminated substantially uniformly by sunlight, resulting in a largely uniform temperature distribution across the array. In contrast, in laser power beaming, the laser bean illuminating a PV cell array often exhibits as non- uniform time-averaged irradiance profile, such as a Gaussian profile, to efficiently transmit optical over long distances. Under non-uniform illumination, different parts of the PV cell array experience varying irradiance levels, leading to suboptimal photoelectric conversion efficiency. The highest photoelectric conversion efficiency is expected when the photon energy matches or slightly exceeds the bandgap energy of PV material. Laser power beaming can achieve high photoelectric conversion efficiencies because the beam wavelength Abeam can be closely matched to the PV material’s bandgap energy, or vice versa. This makes laser power beaming an attractive method for point-to-point wireless power transfer. However, the peak conversion efficiency wavelength Apeak of a PV cell array depends not only on the beam wavelength Abeam, but also on the array’s temperature, especially at the high irradiance levels typical of laser power beaming. This is because the bandgap energy of semiconductor materials varies with temperature, generally decreasing as temperature increases. As a result of temperature -induced changes in bandgap energy, the peak conversion efficiency wavelength Apeak is generally expected to increase as the temperature of the PV cell array rises due to beam heating. Because non-uniform irradiation causes a non-uniform temperature profile across the PV cell array, some PV cells operate suboptimally due a mismatch between their temperature -dependent peak conversion efficiency wavelengths Apeak and the beam wavelength Abeam. This can create bottlenecks within the PV cell array’s electrical circuit, limiting the overall photoelectric conversion efficiency and leading to reduced performance.

[0050] In this context, the PV receiver 100 depicted in Fig. 1 incorporates a heat sink 104, which serves as a substrate for the PV cell array 102. The heat sink 104 includes a PCM arrangement 112 characterized by a non- uniform heat dissipation profile designed to reduce temperature non-uniformities across the PV cell array 102 by counteracting non-uniform heating effects. Depending on the specific application, the PCM arrangement 112 can be configured in various ways to achieve this non-uniform heat dissipation profile, as detailed below.

[0051] Referring to Fig. 2, an example of a heat sink 104 featuring a PCM arrangement 112 is depicted, in accordance with an embodiment. The PCM arrangement 112 includes a plurality of PCM regions 1201-1203, each characterized by a different value of a physical property affecting heat dissipation. These regions 120i- 120s collectively create the non-uniform heat dissipation profile of the PCM arrangement 112. In this example, the first PCM region 120i is circular and located in a central region of the heat sink 104, the second PCM region1202 is annular and surrounds the first PCM regions 120i , and the third PCM region 120;. which is also annular, surrounds the second PCM regions 1202. Of course, other embodiments may utilize PCM regions of varying sizes, shapes, and arrangements. Furthermore, while Fig. 2 depicts three PCM regions 120i- I2O3 for illustrative purposes, other embodiments may include two or more than three PCM regions with different heat-dissipation- related properties, depending on the specific application.

[0052] In some embodiments, the PCM arrangement 112 is configured to undergo reversible solid-to-liquid transitions. In such cases, the PCM arrangement 112 may include multiple PCM compartments 122, each hermetically sealed to contain a specific amount of PCM, thereby preventing leakage during and after the solid- to-liquid transition. For example, in Fig. 2, the first PCM region 120i includes a single PCM compartment 122, while the second and third PCM regions 1202, 120s each include eight PCM compartments 122. The total number of PCM compartments 122, the number per PCM region, as well as their sizes, shapes, and arrangements may vary depending on the specific application.

[0053] While solid-to-liquid PCMs offer advantages in heat dissipation applications due to their large energy storage capacity and relatively small volume change during phase transitions, the present techniques are not limited to this type. The disclosed techniques can also be implemented with PCMs exhibiting solid-to-solid transitions, liquid-to-liquid transitions, liquid-to-gas transitions, and transitions between intermediate states of matter (e.g., crystalline structures) and between reversible chemical reactions (e.g., thermochemical energy storage).

[0054] In some embodiments, the physical property affecting heat dissipation can include thermal conductivity, specific heat capacity, volumetric heat capacity, specific heat of fusion, phase transition temperature, or any combination thereof. In the illustrated embodiment, the PCM regions 120i - 120s differ from one another in PCM composition to provide different values of the physical property affecting heat dissipation. Specifically, the first PCM region 120i contains a first PCM with a first composition M\, the second PCM region 1202 contains a second PCM with a second composition M2, and the third PCM region I2O3 contains a third PCM with a third composition M3, where the first, second, and third compositions Mi, M2, and M3 are all different from one another.

[0055] In another embodiment depicted in Fig. 3, the PCM regions 120i - I2O3 may differ from one another in PCM density, while maintaining the same PCM composition, to achieve varying heat dissipation properties. Specifically, the first PCM region 120i contains a first PCM with a first density p\, the second PCM region 1202 contains a second PCM with a second composition pi, and the third PCM region I2O3 contains a third PCM with a third composition pi, where the first, second, and third densities p\, pi, and pi are all different from one another. In yet other embodiments, any combination of composition, density, or other PCM parameters (e.g., mass or volume) may be used to create different heat dissipation profiles across the PCM regions.

[0056] Referring to Figs. 1 and 2, in some embodiments, the transmission beam 108 illuminating the PV cell array 102 may have a non-uniform beam irradiance profde with a radially decreasing intensity distribution (e.g., a Gaussian profde), where a stronger intensity illuminates the central portion of the PV cell array 102, and a weaker intensity illuminates the peripheral portion of the PV cell array 102 disposed around the central portion. As a result, the PV cell array 102 is therefore expected to exhibit a non-uniform temperature profde with a radially decreasing intensity distribution, with temperatures higher in the central portion compared to the peripheral portion. To counteract this non-uniform heating, the PCM arrangement 112 may include at least one region (e.g., the first PCM region 120i in Fig. 2) located under the central portion of the PV cell array 102, and at least one other PCM region (e.g., the second and third PCM regions 1202, 1203in Fig. 2) located under the peripheral portion. In this configuration, the non-uniform heat dissipation profde of the PCM arrangement 112 may exhibit a radially decreasing heat dissipation efficiency, with the heat dissipation efficiency of the first PCM region 120i being higher than of the second PCM region 1202, and the heat dissipation efficiency of the second PCM region 1202being higher than that of the third PCM region 1203.

[0057] It should be noted that the present techniques can be applied to counteract the effects of any non- uniform beam irradiance profde and are not limited to Gaussian or similar distributions with peak intensity at the beam center and radially decreasing intensity outward. For example, in some embodiments, if the non- uniform beam irradiance profde has a first intensity level across a first portion of the PV cell array 102 and a second, weaker intensity level across a second portion, the PCM arrangement 112 may include at least one first PCM region located under the first portion and at least one second PCM region located under the second portion, where the heat dissipation efficiency of the at least one first PCM region is higher.

[0058] Referring to Figs. 4 and 5, in some embodiments, the heat sink 104 may further include heat pipes 124 (or other heat dissipating structures) in thermal contact with the PCM arrangement 112. The heat pipes 124 are configured to enhance thermal conductivity and further dissipate the heat generated by the PV cell array 102. The number, size shape, and arrangement of the heat pipes 124 depicted in Figs. 4 and 5 may be varied depending on the specific application. Except for the addition of the heat pipes 124, the embodiments of Figs. 4 and 5 may otherwise correspond to the embodiments of Figs. 2 and 3, respectively.

[0059] Various types of PCMs can be used to implement the present techniques. Non-limiting examples of PCMs include organic PCMs (e.g., paraffins, fatty acids, esters, sugar alcohols), inorganic PCMs (e.g., salts, salt hydrates, metals, alloys), and combinations of organic and / or inorganic PCMs (e.g., eutectic PCMs). The phase transition temperature (e.g., melting temperature) of the one or more PCMs included in the PCM arrangement 112 can be adjusted based on various operating parameters and conditions of the PV receiver 100 (e.g., operating temperature, ambient temperature, irradiance levels). For example, in some embodiments, the phase transition temperature can range from about -150 °C to about 50 °C, although values outside this range can be used in other embodiments.

[0060] Referring to Fig. 6, a flow diagram of a method 200 for heat dissipation in PV power generation. The method 200, as shown in Fig. 6, may be implemented in a PV receiver 100 as described with reference to Figs. 2 to 5 or another PV receiver. The method 200 includes a step 202 of receiving a transmission beam on a PV cell array to convert the transmission beam into electrical power, where the transmission beam has a non- uniform beam irradiance profde causing non-uniform heating of the PV cell array. The method 200 also includes a step 204 disposing a heat sink in thermal contact with the PV cell array to absorb and dissipate heat generated by the PV cell array over time under illumination by the transmission beam, the heat sink including a PCM arrangement characterized by a non-uniform heat dissipation profde configured to counteract the non- uniform heating of the PV cell array. Various aspects and features for implementing the method 200 are described above with respect to system implementations.

[0061] It is appreciated that while several embodiments described above involve PV receivers under non- uniform illumination from a transmission beam emitted from a beam transmitter (e.g., a laser beam emitted by a laser source in laser power beaming applications), other embodiments can include PV receivers illuminated by other sources of non-uniform illumination, such as in sunlight in solar-power applications.

[0062] Throughout the present description, similar features in drawings have been given similar reference numerals. To avoid cluttering certain figures, some elements may not be indicated if previously identified in preceding figures. Elements in drawings are not necessarily depicted to scale, emphasis being on clearly illustrating elements and structures of disclosed embodiments. Positional descriptors indicating the location or orientation of one element relative to another are used for ease and clarity of description. Unless indicated otherwise, these descriptors should be understood in the context of the figures and should not be considered limiting. Such spatially relative terms are intended to encompass different orientations in use or operation of disclosed embodiments, in addition to orientations exemplified in the figures. Furthermore, when a first element is referred to as being “on”, “above”, “below”, “over”, or “under” a second element, the first element can be directly or indirectly on, above, below, over, or under the second element, respectively, such that one or multiple intervening elements may be disposed between the first element and the second element.

[0063] The terms “a”, “an”, and “one” are defined herein to mean “at least one”, and do not exclude a plural number of elements, unless stated otherwise.

[0064] The term “or” is defined herein to mean “and / or”, unless stated otherwise.

[0065] Terms such as “substantially”, “generally”, and “about”, which modify a value, condition, or characteristic of a feature of an exemplary embodiment, should be understood to mean that the value, condition, or characteristic is defined within tolerances that are acceptable for the proper operation of this exemplary embodiment for its intended application, or that fall within an acceptable range of experimental error. Inparticular, the term “about” generally refers to a range of numbers that one skilled in the art would consider equivalent to the stated value (e.g., having the same or nearly the same function or result). In some instances, the term “about” means a variation of ±10% of the stated value. It is noted that all numerical values used herein are assumed to be modified by the term “about”, unless stated otherwise.

[0066] The term “based on” as used herein is intended to mean “based at least in part on”, whether directly or indirectly, and to encompass both “based solely on” and “based partly on”. In particular, the term “based on” may also be understood as meaning “depending on”, “representative of’, “indicative of’, “associated with”, “relating to”, and the like.

[0067] The terms “match”, “matching”, and “matched” refer herein to a condition in which two or more elements are either the same or within some predetermined tolerance of one another. These terms are meant to encompass not only “exactly” or “identically” matching the two or more elements, but also “substantially”, “approximately”, or “subjectively” matching the elements, as well as providing a higher or best match among a plurality of matching possibilities.

[0068] The terms “connected” and “coupled”, and derivatives and variants thereof, refer herein to any connection or coupling, either direct or indirect, between two or more elements, unless stated otherwise. For example, the connection or coupling between the elements may be mechanical, optical, electrical, magnetic, thermal, chemical, logical, fluidic, operational, or any combination thereof.

[0069] The term “concurrently” refers herein to the simultaneous or overlapping occurrence of two or more processes. The term “concurrently” does not necessarily imply complete synchronicity but encompasses various scenarios. These scenarios include the simultaneous occurrence of two processes; a first process that both begins and ends during the duration of a second process; and a first process that starts during the duration of a second process but ends after the second process is completed.

[0070] The term “measured” when referring to a quantity or parameter is intended to mean that the quantity or parameter can be measured either directly or indirectly. In the case of indirect measurement, the quantity or parameter can be derived, retrieved, inferred or otherwise determined from directly measured data.

[0071] Numerous modifications could be made to the embodiments described above without departing from the scope of the appended claims.

Claims

CLAIMS1. A photovoltaic (PV) receiver, comprising: a PV cell array configured to receive a transmission beam having a non-uniform beam irradiance profile and convert the transmission beam into electrical power, the non-uniform beam irradiance profile resulting in non-uniform heating of the PV cell array; and a heat sink configured to absorb and dissipate heat generated by the PV cell array, the heat sink comprising a phase-change material (PCM) arrangement having a non-uniform heat dissipation profile configured to counteract the non-uniform heating of the PV cell array.

2. The PV receiver of claim 1, wherein the PCM arrangement comprises a plurality of PCM regions characterized by different values of a physical property affecting heat dissipation, the plurality of PCM regions defining the non-uniform heat dissipation profile of the PCM arrangement.

3. The PV receiver of claim 2, wherein the physical property affecting heat dissipation comprises thermal conductivity, specific heat capacity, volumetric heat capacity, specific heat of fusion, phase transition temperature, or any combination thereof.

4. The PV receiver of claim 2 or 3, wherein the PCM regions differ from one another in PCM composition to provide the different values of the physical property affecting heat dissipation.

5. The PV receiver of any one of claims 2 to 4, wherein the PCM regions differ from one another in PCM density to provide the different values of the physical property affecting heat dissipation.

6. The PV receiver of any one of claims 2 to 5, wherein: the non-uniform beam irradiance profile has a radially decreasing intensity distribution with a stronger intensity illuminating a central portion of the PV cell array and a weaker intensity illuminating a peripheral portion of the PV cell array disposed around the central portion; the plurality of PCM regions comprises a first PCM region located under the central portion and a second PCM region located under the peripheral portion; and the non-uniform heat dissipation profile of the PCM arrangement has a higher heat dissipation efficiency in the first PCM region is than in the second PCM region.

7. The PV receiver of claim 6, wherein the non-uniform beam irradiance profile has a Gaussian distribution.

8. The PV receiver of claim 6 or 7, wherein the first PCM region has a circular shape and the second PCM region has an annular shape.

9. The PV receiver of any one of claims 2 to 5, wherein: the non-uniform beam irradiance profile has a first intensity level across a first portion of the PV cell array and a second intensity level across a second portion of the PV cell array, with the first intensity level being higher than the second intensity level; the plurality of PCM regions comprises a first PCM region located under the first portion and a second PCM region located under the second portion; and the non-uniform heat dissipation profile of the PCM arrangement has a higher heat dissipation efficiency in the first PCM region than in the second PCM region.

10. The PV receiver of any one of claims 6 to 9, wherein the first PCM region has a first PCM composition and the second PCM region has a second PCM composition different from the first PCM composition.11 . The PV receiver of any one of claims 6 to 10, wherein the first PCM region has a first PCM density and the second PCM region has a second PCM density less than the first PCM density.

12. The PV receiver of any one of claims 6 to 11, wherein the first PCM region comprises at least one first PCM compartment, each first PCM compartment configured to receive a respective amount of PCM, and wherein the second PCM region comprises at least one second PCM compartment, each second PCM compartment configured to receive a respective amount of PCM.

13. The PV receiver of any one of claims 1 to 12, wherein the PCM arrangement is configured to undergo reversible solid -to-liquid transitions.

14. The PV receiver of any one of claims 1 to 13, wherein the heat sink further comprises heat pipes in thermal contact with the PCM arrangement and configured to provide further dissipation of the heat generated by the PV cell array.

15. The PV receiver of any one of claims 1 to 14, wherein the transmission beam is transmitted from a beam transmitter, the beam transmitter and the PV receiver forming a power beaming system.

16. The PV receiver of claim 15, wherein the transmission beam is a laser beam.

17. The PV receiver of any one of claims 1 to 14, wherein the transmission beam comprises sunlight.

18. A power beaming system comprising: a beam transmitter configured to transmit a transmission beam; and a PV receiver in accordance with any one of claims 1 to 14, wherein the PV receiver is configured to receive the transmission beam from the beam transmitter and convert the transmission beam into electrical power.

19. A method for heat dissipation in photovoltaic (PV) power generation, the method comprising: receiving a transmission beam on a PV cell array to convert the transmission beam into electrical power, the transmission beam having a non-uniform beam irradiance profile that causes non-uniform heating of the PV cell array; and disposing a heat sink in thermal contact with the PV cell array to absorb and dissipate heat generated by the PV cell array over time under illumination by the transmission beam, the heat sink comprising a phasechange material (PCM) arrangement with a non-uniform heat dissipation profile configured to counteract the non-uniform heating of the PV cell array.

20. The method of claim 19, further comprising: providing the PCM arrangement with a plurality of PCM regions characterized by different values of a physical property affecting heat dissipation, the plurality of PCM regions defining the non-uniform heat dissipation profile of the PCM arrangement.21 . The method of claim 20, wherein providing the PCM arrangement with the plurality of PCM regions comprises: selecting the physical property affecting heat dissipation from thermal conductivity, specific heat capacity, volumetric heat capacity, specific heat of fusion, phase transition temperature, or any combination thereof.

22. The method of claim 20 or 21, wherein providing the PCM arrangement with the plurality of PCM regions comprises: configuring the PCM regions to differ from one another in PCM composition to provide the different values of the physical property affecting heat dissipation.

23. The method of any one of claims 20 to 22, wherein providing the PCM arrangement with a plurality of PCM regions comprises: configuring the PCM regions to differ from one another in PCM density to provide the different values of the physical property affecting heat dissipation.

24. The method of any one of claims 20 to 23, wherein: the non-uniform beam irradiance profile has a radially decreasing intensity distribution with a stronger intensity illuminating a central portion of the PV cell array and a weaker intensity illuminating a peripheral portion of the PV cell array disposed around the central portion; and providing the PCM arrangement with a plurality of PCM region comprises: providing a first PCM region located under the central portion and a second PCM region located under the peripheral portion; andconfiguring the non-uniform heat dissipation profile of the PCM arrangement to have a higher heat dissipation efficiency in the first PCM region is than in the second PCM region.

25. The method of claim 24, wherein the non-uniform beam irradiance profile has a Gaussian distribution.

26. The method of claim 24 or 25, wherein providing the first PCM region and the second PCM region comprises: providing the first PCM region with a circular shape and the second PCM region with an annular shape.

27. The method of any one of claims 20 to 23, wherein: the non-uniform beam irradiance profile has a first intensity level across a first portion of the PV cell array and a second intensity level across a second portion of the PV cell array, with the first intensity level being higher than the second intensity level; and providing the PCM arrangement with a plurality of PCM region comprises: providing a first PCM region located under the first portion and a second PCM region located under the second portion; and providing the non-uniform heat dissipation profile of the PCM arrangement with a higher heat dissipation efficiency in the first PCM region is than in the second PCM region.

28. The method of any one of claims 24 to 27, wherein providing the first PCM region and the second PCM region comprises: providing the first PCM region with a first PCM composition and the second PCM region with a second PCM composition different from the first PCM composition.

29. The method of any one of claims 24 to 28, wherein providing the first PCM region and the second PCM region comprises: providing the first PCM region with a first PCM density and the second PCM region with a second PCM density less than the first PCM density.

30. The method of any one of claims 24 to 29, wherein providing the first PCM region and the second PCM region comprises: providing the first PCM region with at least one first PCM compartment, each first PCM compartment configured to receive a respective amount of PCM; and providing the second PCM region with at least one second PCM compartment, each second PCM compartment configured to receive a respective amount of PCM.

31. The method of any one of claims 19 to 30, wherein the PCM arrangement is configured to undergo reversible solid -to-liquid transitions.

32. The method of any one of claims 19 to 31, further comprising: providing the heat sink with heat pipes in thermal contact with the PCM arrangement and configured to provide further dissipation of the heat generated by the PV cell array.

33. The method of any one of claims 19 to 32, further comprising: receiving the transmission beam from a beam transmitter, the beam transmitter and the PV receiver forming a power beaming system.

34. The method of claim 33, wherein the transmission beam is a laser beam.

35. The method of any one of claims 19 to 32, wherein the transmission beam comprises sunlight.

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