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Experimental study on cooling of high-power laser diode arrays using hybrid microchannel and slot jet array heat sink
摘要： In this study, a hybrid microchannel and slot jet array heat sink is designed and fabricated to achieve a better thermal performance of the high-power laser diode arrays. A standard commercial laser bar with wavelength of 808 nm is packaged on the heat sink and experiments are performed to assess the cooling performance of the hybrid heat sink. In the experiments, the forward voltage method is used to measure the chip temperature and the structure function method is applied to obtain the thermal resistance of the heat sink. Using the deionized water as coolant, the heat sink deals with a heat flux of up to 506 W/cm2 and the thermal resistance of the heat sink is only 0.23 K/W when the flow rate is 0.8 L/min (The average jet velocity is 13.3 m/s). The optical power can be up to 135.5 W corresponding to the wall plug efficiency of 64.2%. Compared with the published solutions related to cooling similar laser chips, the thermal resistance reduces by over 15%, indicating that this hybrid heat sink is an interesting solution to improve the cooling of the high-power laser diode arrays.
关键词： High-power laser diode array,Cooling,Forward voltage method,Thermal resistance,Optical power
更新于2025-09-16 10:30:52
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Performance, Limits, and Thermal Stress Analysis of High Concentrator Multijunction Solar Cell under Passive Cooling Conditions
摘要： Concentration of solar radiation onto the surface of triple-junction solar cells causes high cell temperature and system failure. Recently, several cooling methods were proposed for these systems. However, quantitative evaluation of the essential heat transfer coefficients to maintain stable operation of these systems at different meteorological and operating conditions is not found in the literature. Therefore, in this study, a comprehensive three-dimensional coupled thermal and structural model is proposed for the latest triple-junction AZUR SPACE solar cell. The model is used to investigate the performance of an HCPV system under different solar concentration ratios (CRs), ambient temperature, direct solar irradiance, wind speed, backside heat transfer coefficient, and copper-II substrate area ratios. In addition, a new structure of the solar cell is proposed by modifying the typical solar cell assembly by changing the area of the rear copper layer. The results indicate that by increasing the ambient temperature, CR and direct solar irradiance significantly increase the predicted cell temperature at the same backside heat transfer coefficient. In addition, increasing copper-II substrate area ratios significantly reduces the average cell temperature at the same backside heat transfer coefficient and CR. At the highest backside heat transfer coefficient, when the copper-II substrate area increased, the cell temperature decreased to a certain limit and subsequently remained constant. Critical values of the highest backside heat transfer coefficient were about 200, 600, 1000, and 1600 W/m2 K at CRs of 50, 500, 1000, and 1500 Suns, respectively. In addition, at the highest backside heat transfer coefficient of 1600 W/m2 K, the critical area ratio values were about 2, 3, 4, and 6 at CRs of 50, 500, 1000, and 1500 Suns, respectively.
关键词： Passive cooling,Concentrator photovoltaic,Thermal stress,Triple-junction solar cell
更新于2025-09-16 10:30:52
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The cooling rate controlled (040) facets of BiVO<sub>4</sub> particles and its characterization
摘要： The photogenerated carriers of BiVO4 are easily recombined and desired to be improved effectively. In this paper, the separation degree was improved by prolonging the cooling time in the process of BiVO4 synthesis. When the cooling rate was 50℃/h, the performance of BiVO4 particles was significantly optimized, including the highest peak of (040) facets, the improvement of morphology, the increase of carriers separation and the optimum degradation of doxycycline. When the degradation time was only 15min, doxycycline in water could be effectively removed with a removal rate of 63%. These studies are valuable for improving the chemical properties of BiVO4 and broadening its application.
关键词： degradation,(040) facets,BiVO4,cooling rate
更新于2025-09-16 10:30:52
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Assessment of Existing Photovoltaic System with Cooling and Cleaning System: Case Study at Al-Khobar City
摘要： There is no denial that renewable energy is considered to be the most cost-competitive source of clean power in many parts of the world. Saudi Arabia’s vision 2030 aims at achieving the best by using di?erent sources of renewable energy such as solar energy, wind energy, and others. The use of solar energy in particular for power generation will decrease the dependency on oil, and thus, decrease the greenhouse gasses. Solar panels e?ciency tends to decrease with the accumulation of dust on their surface. Thus, a cleaning process requires assigning and employing labor, which increases the cost of running as well as high cost of machinery. The current study focuses on assessing and designing a simple auto self-cleaning system in order to improve the e?ciency of the solar panel. The results showed that for the Al-Khobar region, Eastern Province, Kingdom of Saudi Arabia, the e?ciency of the solar panels after cleaning was increased from 6% to an average of 12% at nominal temperature of 27 C. In addition, the average power output was increased by 35% during the day time. In addition, the normal e?ciency of the solar panels before cooling was between 10% to 15% at 42 C and the e?ciency increased by 7%. Moreover, the output power was increased by 31% with maximum e?ciency of 32% at noon time. After cooling, the temperature of solar cells decreased to 20 C.
关键词： cooling,real case study,e?ciency,photovoltaic systems,renewable energy,cleaning
更新于2025-09-16 10:30:52
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Water cooling assisted laser dissimilar welding with filler wire of nickel-based alloy/austenitic stainless steel
摘要： To clarify the e?ects of water cooling on solidi?cation behavior of pulsed laser welding of Nickel-based alloy/austenitic stainless steel with ?ller wire, and to improve the mechanical properties of laser welded joints, the analyses of morphology, microstructure, anti-peel property and micro-hardness were carried out. The results indicated that adding water cooling increased cooling rate and temperature gradient of the weld. And the addition of water cooling made constitutional supercooling of the weld easier, so that the solidi?cation rate increased with the increase of the temperature gradient. Therefore, the weld grain was re?ned by about 28%, and the average width of unmixed zone decreased by 35%, with a low volume fraction of Mo-rich precipitated phase consisting of p phase and μ phase. The μ phase was discovered in laser welding Nickel-based alloy/austenitic stainless. Both p phase and μ phase had a good coherent relationship with the matrix, which resulted in the low phase boundary energy between precipitated phase and matrix. The coherent relationship is described as [1 4 3] p // [5 3 1] γ between the p phase and the matrix. And the coherent relationship is described as [1 2 0] μ // [2 2 1] γ between the μ phase and the matrix. There are the stacking faults in the μ phase along the direction of [1 1 0], which is one of the slip system in μ phase. At the same time coherent relationship between p phase and matrix is better than that of μ phase. The micro-hardness, load capacity per length, and anti-peel stress were improved by 10.5%, 8.1%, and 11.8%, respectively.
关键词： Ni-based alloy,Precipitated phase,Filler wire,Water cooling assisted,Laser dissimilar welding
更新于2025-09-16 10:30:52
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Photovoltaic panel integrated with phase change materials (PV-PCM): technology overview and materials selection
摘要： In recent years, the utilization of phase change materials (PCMs) in photovoltaic (PV) module for thermal regulation has attracted wide attention in this field, as the hybrid PV-PCM technology can not only achieve higher photoelectric conversion efficiency but also make it possible to extract thermal energy stored in PCMs for cascade utilization. Although substantial research has been carried out on PV-PCM systems, the promise of practical application is still far from clear with some barriers unsolved, such as PCMs which need further improvements in both technical and economical view. In this paper, a comprehensive literature review of the state-of-the-art aspects of PV-PCM systems is presented, with the focus on technology overview and materials selection. The concept of hybrid PV-PCM system is first discussed with its general configuration and energy balance, to figure out the key factors affecting its performance. Besides, the development route of PV-PCM research is outlined through a comprehensive review of 104 research articles during 2004–2018, clarifying the representative achievements and existing problems in each stage. Furthermore, PCMs are highlighted in this paper with details on their classification, properties, and application in previous PV-PCM research. In particular a triangle about materials selection criteria and determination strategy of phase transition temperature is proposed. Finally, the challenges and prospects of future research on PV-PCM systems are raised, advocating that more attention should be addressed on new strategies to overcome the existing problems such as insufficient reliability and economic feasibility.
关键词： Phase change material (PCM),PV cooling,PV-PCM,Solar photovoltaic (PV),Review
更新于2025-09-16 10:30:52
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Annual Energy Harvesting of Passively Cooled Hybrid Thermoelectric Generator-Concentrator Photovoltaic Modules
摘要： Approximately 60% of the incident energy is dissipated as heat in conventional concentrator photovoltaic modules. The hybridization with thermoelectric generators (TEGs) aims to recover part of the waste heat and transform it to electricity. Recently, the feasibility of passively cooled designs has been assessed for small sized solar cells (3 mm × 3 mm). It is expected that novel prototypes will be developed according to this concept. However, the existing feasibility studies are based on reference operating conditions, while the behavior of the hybrid modules under changing atmospheric conditions remains unknown. In this article, real atmospheric data of Jaén, Southern Spain, including irradiance, temperature, and spectral data, are used to analyze the behavior of four designs of TEG-concentrator photovoltaic modules: low ZT-low temperature (A), low ZT-high temperature (B), high ZT-low temperature (C), and high ZT-high temperature (D). This behavior is compared with that of a typical concentrator photovoltaic-only module. Results show that, while the global ef?ciency at reference conditions can be enhanced up to 4.75%, the annual averaged global ef?ciency can only be increased up to 4.30%. The results of this article will help to understand the impact of the atmospheric conditions on the real behavior of these structures.
关键词： concentrator photovoltaics (CPV),efficiency improvement,Annual energy,thermoelectric generator (TEG),hybrid system,passive cooling
更新于2025-09-16 10:30:52
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Manufacture of the Transceiver Housing for an Active Phased Array Antenna with Built-In Cooling Channels by Selective Laser Melting
摘要： A cooled transceiver housing of an active phased array antenna is produced by 3D printing from aluminum, on the basis of selective laser melting (SLM). The housing walls contain cooling channels, whose geometry ensures effective heat transfer from the active electronic components of the transceiver and also permits the manufacture of high-quality samples on existing 3D printing systems and facilitates cleaning of the channels after printing. The housing is made of AlSi10Mg aluminum, with an acceptable content of closed pores (no more than 1%). Its physicomechanical properties correspond to those of regular aluminum alloys used in the traditional manufacturing technology for such components. This housing may be used in advanced radar systems. The research permits recommendations for further development of the technology.
关键词： cooling channels,3D printing,transceiver housing,active phased array antenna,AlSi10Mg aluminum
更新于2025-09-16 10:30:52
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Theoretical and Numerical Study of a Photovoltaic System with Active Fluid Cooling by a Fully-Coupled 3D Thermal and Electric Model
摘要： The paper deals with the three-dimensional theoretical and numerical investigation of the electrical performance of a Photovoltaic System (PV) with active fluid cooling (PVFC) in order to increase its efficiency in converting solar radiation into electricity. The paper represents a refinement of a previous study by the authors in which a one-dimensional theoretical model was presented to evaluate the best compromise, in terms of fluid flow rate, of net power gain in a cooled PV system. The PV system includes 20 modules cooled by a fluid circulating on the bottom, the piping network, and the circulating pump. The fully coupled thermal and electrical model was developed in a three-dimensional geometry and the results were discussed with respect to the one-dimensional approximation and to experimental tests. Numerical simulations show that a competitive mechanism between the power gain due to the cell temperature reduction and the power consumption of the pump exists, and that a best compromise, in terms of fluid flow rate, can be found. The optimum flow rate can be automatically calculated by using a semi-analytical approach in which irradiance and ambient temperature of the site are known and the piping network losses are fully characterized.
关键词： thermal–electrical model,solar energy,photovoltaic modules,active cooling,computational fluid dynamics (CFD)
更新于2025-09-16 10:30:52
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A novel solar system integrating concentrating photovoltaic thermal collectors and variable effect absorption chiller for flexible co-generation of electricity and cooling
摘要： Traditional single effect and double effect absorption chillers have relatively narrow working temperature ranges, which limits their application of solar systems. This study proposes a novel solar system integrating concentrating photovoltaic and thermal collectors, and a variable effect absorption chiller, for more flexible and efficient co-generation of electricity and cooling. In this study, variable effect chiller was optimized, showing that three working modes, combined with optimized control, make variable effect chillers a superior choice to the single effect and double effect types. Then, dynamic simulations of the solar co-generation system were performed, in order to study the effects of temperature control on system performance. The results showed that, a high turn-off temperature for the chiller generally results in higher cooling power, shorter working hours for the chiller, and in some cases, a frequent on–off cycling of chiller. With the increase in working temperature level, the cooling exergy efficiency increases, but total exergy efficiency decreases due to the photovoltaic cell’s degraded performance. The total exergy efficiency is approximately 32%–33%. A larger difference between turn-on and turn-off temperatures delays the start time of the chiller while ensuring the full use of solar energy. By adjusting the temperature control strategy, the novel solar co-generation system can offer a cooling-electricity ratio from 1.4 to 2.0, which is capable of meeting the demands in many cases. The proposed system offers flexible co-generation of cooling and electricity.
关键词： Exergy efficiency,Solar cooling,Concentrating photovoltaic and thermal (CPV/T) collector,Dynamic simulation,Variable effect absorption refrigeration cycle
更新于2025-09-16 10:30:52