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Silver ants-inspired flexible photonic architectures with improved transparency and heat radiation for photovoltaic devices
摘要： Silver ants forage at extremely high environmental temperatures, the hairs of which play a crucial role in reducing the body temperature via enhanced optical reflection and radiative heat dissipation as a passive daytime radiative cooler. Inspired by the hierarchical feature structure of the hairs, we fabricated the flexible photonic architectures (FPA) on polydimethylsiloxane (PDMS). With some modification to the feature structure, the FPA-PDMS exhibited not only a large emittance in the mid-infrared spectral range, comparable with that of state-of-the-art thermal emitters, but also the record-high transmittance and haze in the visible and near-infrared range, which would be particularly appealing to photovoltaic devices for maximizing sunlight absorption and minimizing parasitic heat. The ease of application of the FPA-PDMS was demonstrated in both emerging perovskite and mature commercial crystalline silicon solar cells, where the FPA-PDMS was electrostatically attached to their glass superstrates or covers and the improvements in photovoltaic characteristics as a result of enhanced light harvesting were confirmed through laboratory measurements. Though the synergetic effects of the improved transparency and heat radiation brought by the FPA-PDMS need to be characterized outdoors in the future, these findings pave the way for suppressing optical and thermal losses simultaneously in opto-electric-thermal coupled devices through learning sophistically evolved photonic architectures from nature.
关键词： Flexible photonic architectures,Photovoltaic devices,Silver ants,Light-thermal management
更新于2025-09-16 10:30:52
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Experimental study and exergy analysis of photovoltaic-thermoelectric with flat plate micro-channel heat pipe
摘要： Effective cooling of the photovoltaic can enhance electrical conversion efficiency of a photovoltaic system. The combination of photovoltaic and thermoelectric generator provides unique advantages because of their complementary characteristics. In addition, hybrid photovoltaic-thermoelectric can utilize a wider solar spectrum thereby harvesting more energy from the sun. Heat pipes are passive devices that can transfer heat efficiently over a long distance. Therefore, this study presents an experimental investigation and exergy analysis of a photovoltaic-thermoelectric with flat plate micro-channel heat pipe. The experiment is performed in a laboratory using a solar simulator and water-cooling is used for the thermoelectric generator. The effect of thermoelectric load resistance, micro-channel heat pipe back insulation and solar radiation on the performance of the hybrid system is presented and a comparison with a photovoltaic only system is provided. Results show that the hybrid system provides an enhanced performance compared to the photovoltaic only system and absence of insulation behind the micro-channel heat pipe enhances electrical performance of the hybrid system. Furthermore, results show the feasibility of the hybrid system for generating electricity and small hot water. This study will provide valuable guidance for design of photovoltaic-thermoelectric systems with heat pipe and verifies the feasibility of such systems.
关键词： Thermal management,Power generation,Exergy,Micro-channel heat pipe,Photovoltaic-thermoelectric
更新于2025-09-16 10:30:52
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Integrated microsensor for precise, real-time measurement of junction temperature of surface-mounted light-emitting diode
摘要： Light-emitting diodes (LEDs) are widely used in many industrial applications owing to their high performance and efficiency compared with conventional lighting systems. However, a considerable amount of input power is inevitably dissipated into heat at the LED junction, which can degrade the performance and reliability of the LED; thus, it is important to monitor the change in the junction temperature of the LED. In this study, we present a micro-temperature sensor-integrated surface-mounted device (SMD) for accurate and real-time measurement of the junction temperature of an LED. The LED is mounted on a microfabricated Pt sensor in a similar way to the typical SMD assembly. The heat generated at the LED junction is conductively transferred to the microsensor, increasing the temperature and changing its electrical resistance. In contrast to the conventional techniques for thermal characterization of LEDs, the integrated microsensor provides real-time information on the junction temperature with high precision, reproducibility, and simplicity. Additionally, the temperature of the solder, which is not easily accessible but is closely related to the reliability of the LED, can be estimated by analyzing the thermal resistance of the LED package. Experimental and numerical results indicate a linear correlation (R2 = 0.988) between the junction and sensor temperatures, which is practically useful for the thermal management of the miniaturized SMD-LED.
关键词： Junction temperature,Light-emitting diode,Thermal transient test,Microsensor,Surface-mounted device,Thermal management
更新于2025-09-12 10:27:22
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Performance analysis of a photovoltaic panel integrated with phase change material
摘要： The conversion efficiency of photovoltaic (PV) panels is reduced while the PV temperature rises. It is revealed that that every Celsius degree rise in PV temperature can result in as large as a 0.65% drop in the efficiency. This phenomenon attracts substantial scholar attentions in mitigating and controlling the PV temperature. Among those applied techniques, phase change material (PCM) is considered as a potential candidate to hold the PV temperature at a low degree because of its latent heat storage. The integrated system is therefore named PV-PCM system. In this study, the daily performance and viability of this system was evaluated through simulation, illustrating that the temperature of PV can be reduced by 24.9°C through adding PCM, and hence the electricity output increased by up to 11.02%. This study also demonstrates that the latent heat capacity of PCM and natural convection of melted PCM can control PV temperature and enhance the heat dissipation rate from PV to PCM rate by 4 to 5 times.
关键词： Photovoltaic,Phase change material,PV-PCM,Passive cooling,Thermal management
更新于2025-09-12 10:27:22
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Experimental study of active phase change cooling technique based on porous media for photovoltaic thermal management and efficiency enhancement
摘要： The photoelectric conversion efficiency of solar cells was significantly influenced by its operating temperature which promotes the studies in thermal management for photovoltaic (PV). This paper introduced a novel cooling method based on porous media applied in PV panel for thermal management and efficiency enhancement. An active phase change (APC) cooling system has been designed and fabricated to explore the possibility of cooling the PV panel, and ethanol was considered as the working fluid. By laboratory test, average temperature, temperature distribution, electrical performance of the PV panel as well as energy and exergy efficiency were analyzed in detail. The results demonstrated that the average temperature of the PV panel can be better managed by the APC cooling method compared with the uncooled conditions at different irradiation levels. Besides, increasing the non-condensable gas flow rates has a positive effect on the temperature reduction and maximum generated power of the PV panel. The obtained three-dimensional temperature distribution map proved that the temperature distribution was well uniform with the maximum temperature difference less than 5 °C. The maximum specific power improvement and percentage improvement in power generation were 21.37 W/m2 and 19.32%, respectively.
关键词： Photovoltaic,Efficiency enhancement,Active phase change,Thermal management,Porous media
更新于2025-09-12 10:27:22
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Experimental investigation of a photovoltaic thermal collector with energy storage for power generation, building heating and natural ventilation
摘要： A phase change material (PCM) can be used for thermal management of photovoltaics and thermal energy storage. This paper presents a photovoltaic thermal (PVT) system integrated with a PCM as a thermal storage medium for managing the photovoltaic temperature and together with a ventilation duct for preheating supply air or natural ventilation of a building. The novelty of the integrated PVT/PCM system lies in using the PCM as a passive technique not only for PV cooling but also for building heating and ventilation. Experiments have been carried out on a prototype PVT system for different sizes of PCM. The results show that a 30 mm thick PCM layer with a phase change temperature of 25oC can maintain the PV temperature below 45oC and improve the PV electrical efficiency by 10% for about 210 minutes under 600 W/m2 insolation. Increasing the PCM thickness by 10 mm increases the time for thermal control by 60 to 70 minutes. The PVT/PCM system is able to generate a 15 L/s ventilation rate in a vertical duct of 1100 mm wide, 1200 mm high and 100 mm deep during the melting phase and at least 20 L/s during the solidification phase. Use of metal fins to enhance heat transfer in the PCM can increase the PV electrical efficiency further by 3% and the ventilation rate by 30%.
关键词： energy storage,Photovoltaics,phase change material,natural ventilation,thermal management,solar absorber
更新于2025-09-12 10:27:22
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Exergo-economic analysis of a serpentine flow type water based photovoltaic thermal system with phase change material (PVT-PCM/water)
摘要： An investigation on PVT-PCM/water system has been carried out under the weather conditions at Kottayam (9.5425 °N, 76.8202 °E), India. In the present paper, experimentations have been done to compare the overall performance of PV and water-based PVT-PCM panels. The PVT-PCM/water system has been analysed under various outdoor environmental conditions and it has been recorded that the integration of PCM contributed to an improved thermal and overall efficiency of 26.87% and 40.59% respectively, along with a rise in electrical efficiency by 17.33% compared with conventional PV panel. It has been found that the payback time for the water-based PVT-PCM system is about 6 years on the overall exergy basis, which is 11.26% shorter compared to conventional PV panels. Also, the water-based PVT-PCM system has long-term lifecycle conversion efficiency compared to conventional PV panel by about 27%.
关键词： Photovoltaic,PCM,Exergy,Optimization,Thermal management
更新于2025-09-12 10:27:22
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AIP Conference Proceedings [AIP Publishing 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Fes, Morocco (25–27 March 2019)] 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Finite element analysis of cooling mechanism by flat heat-sinks in ultra-high CPV systems
摘要： The potential cost reduction of Concentrator photovoltaic (CPV) systems is closely related to the concentration factor because higher light concentrations imply lower amount of semiconductor material required for the solar cells. However, the thermal management at such ultra-high light fluxes is difficult. The use of small-sized solar cells is beneficial for improving the thermal management. Among the possible cooling strategies, the use of flat-plate heat-sinks for passive cooling, if feasible, would be the simplest way to dissipate heat and would accelerate the development of ultra-high CPV prototypes. In this work, a thermal 3D finite-element model is used to investigate the possibilities of flat-plate heat-sinks for passive cooling at concentration ratios within 2,000-10,000 suns. Results show that a micro solar cells of 1mm x 1mm area can be thermally handled with conventional Aluminium flat plate heat-sinks up to 10,000 suns.
关键词： ultra-high concentration,passive cooling,Concentrator photovoltaic (CPV),thermal management,flat-plate heat-sinks
更新于2025-09-11 14:15:04
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III-V-on-Silicon Integration: From Hybrid Devices to Heterogeneous Photonic Integrated Circuits
摘要： Heterogeneous integration of III-V materials onto silicon photonics has experienced enormous progress in the last few years, setting the groundwork for the implementation of complex on-chip optical systems that go beyond single device performance. Recent advances on the field are expected to impact the next generation of optical communications to attain low power, high efficiency and portable solutions. To accomplish this aim, intense research on hybrid lasers, modulators and photodetectors is being done to implement optical modules and photonic integrated networks with specifications that match the market demands. Similarly, important advances on packaging and thermal management of hybrid photonic integrated circuits (PICs) are currently in progress. In this paper, we report our latest results on hybrid III-V on Si transmitters, receivers and packaged optical modules for high-speed optical communications. In addition, a review of recent advances in this field will be provided for benchmarking purposes.
关键词： III-V on SOI photonic integrated circuits,on-chip silicon transmitters and receivers,lasers,thermal management,silicon photonics packaging
更新于2025-09-11 14:15:04
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Self-assembled monolayer for polymer-semiconductor interface with improved interfacial thermal management
摘要： Reliability and lifespan of highly miniaturized and integrated devices will be effectively improved if excessive accumulated heat can be quickly transported to heat sinks. In this study, both molecular dynamics (MD) simulations and experiments were performed to demonstrate that self-assembled monolayers (SAMs) have high potential in interfacial thermal management and can enhance thermal transport across polystyrene (PS) / silicon (Si) interface, modelling the common polymer/semiconductor interfaces in actual devices. The influence of packing density and alkyl-chain length of SAMs are investigated. Firstly, MD simulations show that the interfacial thermal transport efficiency of SAM is higher with high packing density. The interfacial thermal conductance (ITC) between PS and Si can be improved up to 127 ± 9 MW m-2 K-1, close to the ITC across metal and semiconductor interface. At moderate packing density, the SAMs with less than 8 carbon atoms in alkyl-chain show superior improvements over those with more carbons due to the assembled structure variation. Secondly, time-domain thermoreflectance technique was employed to characterize the ITCs of a bunch of Al/PS/SAM/Si samples. C6-SAM enhances the ITC by 5 folds, from 11 ± 1 MW m-2 K-1 to 56 ± 17 MW m-2 K-1. The interfacial thermal management efficiency will weaken when alkyl-chain exceeds 8 carbon atoms, which agrees with the ITC trend from MD simulations at moderate packing density. The relationship between SAM morphology and interfacial thermal management efficiency is also discussed in detail. This study demonstrates the feasibility of molecular level design for interfacial thermal management from both theoretical calculation and experiment, and may provide a new idea for improving the heat dissipation efficiency of micro devices.
关键词： polymer/semiconductor interface,time-domain thermoreflectance,molecular dynamics simulation,self-assembled monolayer,interfacial thermal management
更新于2025-09-11 14:15:04