Numerical and experimental study on temperature control of solar panels with form-stable paraffin/expanded graphite composite PCM

Luo, Zelun; Huang, Zhaowen; Xie, Ning; Gao, Xuenong; Xu, Tao; Fang, Yutang; Zhang, Zhengguo

doi:10.1016/j.enconman.2017.07.046

Cited by 149 publications

(26 citation statements)

References 32 publications

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“…A variety of heat dissipation approaches, including fin heat sink18–20 and materials phase change,21,22 have been applied to low down the operation temperature of the semiconductor devices. However, the low capacity of heat dissipation using these methods can hardly satisfy the requirements of high‐energy‐density devices 23,24. Radiative cooling technology is promising and can passively dissipate heat from Earth into outer space, but it is only notable at night and the application is limited in outdoor situations 25–27.…”

Section: Figurementioning

confidence: 99%

Promoting Energy Efficiency via a Self‐Adaptive Evaporative Cooling Hydrogel

et al. 2020

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of the temperature, quasi-Fermi levels of holes and electrons become closer to each other under some working conditions, [10,11] and the barrier height of the P-N junction decreases. [10] Moreover, the band gap of the P-N junction reduces and carrier transition from the valence band to conduction band becomes easier. [12,13] These effects bring adverse impacts on a variety of the energy conversion processes including photoelectric conversion, [14,15] electroluminescence, [16] voltage controlled tunneling, [10,17] and so on. Hence, efficiently dissipating the waste heat and maintaining the operation temperature at a low level is essentially important for the semiconductor devices to achieve efficient, reliable, and safe operations.A variety of heat dissipation approaches, including fin heat sink [18][19][20] and materials phase change, [21,22] have been applied to low down the operation temperature of the semiconductor devices. However, the low capacity of heat dissipation using these methods can hardly satisfy the requirements of high-energy-density devices. [23,24] Radiative cooling technology is promising and can passively dissipate heat from Earth into outer space, but it is only notable at night and the application is limited in outdoor situations. [25][26][27] Although active cooling devices such as forced air circulation [28,29] and hydro-cooling, [30,31] show high cooling performance, they have high energy consumptions and require complex auxiliary accessories (e.g., fans or water pumps). These limitations render them little adaptability in either large-scale or portable applications. Simply structured cooling technology with high capacity of heat dissipation remains a great challenge.Herein, we present a universal, simple, efficient, low-cost, and passive cooling strategy to adaptively low down the working temperature of the semiconductor devices. By using its evaporative cooling capability, a thin layer of lithium-and bromine enriched polyacrylamide (PAAm) hydrogel can efficiently dissipate the waste heat induced by nugatory carrier transport in the P-N junctions of a semiconductor device. When attaching the hydrogel onto the semiconductors, it will absorb the heat from the semiconductors, which results in the rising of the hydrogel temperature. And the water molecules will be released and quickly dissipate the waste heat into the ambient air due to the large latent heat of water. This can efficiently cool down the semiconductors for a better working efficiency. In the standby mode, the hydrogel can spontaneously harvest water from its High temperature brings adverse impacts on the energy efficiency, and even destroys a semiconductor device. Here, a novel and cost-effective strategy is proposed to boost the energy efficiency of semiconductor devices by using the self-adaptive evaporative cooling of a lithium-and bromine-enriched polyacrylamide hydrogel. Water inside the hydrogel can quickly evaporate to dissipate the waste heat generated by the nugatory carrier transport in the P-N junction. In dormancy,...

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Section: Figurementioning

confidence: 99%

Promoting Energy Efficiency via a Self‐Adaptive Evaporative Cooling Hydrogel

et al. 2020

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“…The increase of the through-holes diameter reached a maximum cooling effect on the PV modules, above which less cooling occurred. Also, PCM has been proposed as a potential solution, although further cost-effective studies need to be conducted [16][17][18]. Several researchers have proposed the use of thin layers attached to the PV modules, similar to the research carried out by Stropnik et al [17] which achieved an increase of the electrical power by 9.2% under experimental conditions.…”

Section: Pv Modulementioning

confidence: 98%

“…However, the configuration has to be validated experimentally under real conditions, and the volume reduction has to be considered. Other researchers used a PV/PCM system with form-stable paraffin/Expanded Graphite (EG) to improve the uniformity of the temperature distribution of the PV modules and thus improve their power output [18]. The PCM/EG helped to control the temperature and the temperature distribution of the PV modules.…”

Section: Pv Modulementioning

confidence: 99%

Evaluation of New PCM/PV Configurations for Electrical Energy Efficiency Improvement through Thermal Management of PV Systems

et al. 2021

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Photovoltaic modules during sunny days can reach temperatures 35 °C above the ambient temperature, which strongly influences their performance and electrical efficiency as power losses can be up to −0.65%/°C. To minimize and control the PV panel temperature, the scientific community has proposed different strategies and innovative approaches, one of them through passive cooling with phase change materials (PCM). However, further investigation, including the effects of geometric shape, insulation, phase change temperature, ambient temperature, and solar radiation on the PV module power output and efficiency, needs further optimization and research. Therefore, the current work aims to investigate several system configurations and different PCMs (RT42, RT31, and RT25) and compare the system with and without insulation through computational fluid dynamic (CFD) tools. The final goal is to optimise and control the temperature of PV modules and evaluate their system efficiency and energy generation. The results showed that compared with a rectangular shape of the PCM container, the trapezoid-one exhibits a considerably better cooling performance with a negligible variation of the PV temperature, even when the melting temperature of the PCM was lower than the average ambient temperature. Moreover, the study showed that having insulation in the PCM container increases the amount of PCM needed, compared with no insulation case, and the increased amount depends on the PCM type. The newly proposed PV/PCM system configuration shows an efficiency and power generation enhancement of 17% and 14.6%, respectively, at peak times.

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“…Besides, they indicated that the PCM aids to increase efficiency. Luo et al 25 carried out a numerical and experimental study on the temperature management of PV panels using a thermally high conductive composite PCM. They found that the electrical efficiency of PV panels can be significantly increased by PCMs.…”

Section: Introductionmentioning

confidence: 99%

Implications of boundary conditions on natural convective heat transfer of molten phase change material inside enclosures

Arıcı

Yıldız

Nižetić³

et al. 2020

Int J Energy Res

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Summary Considering the significance of the appropriate selection of boundary conditions (BCs) in modelling step for practical engineering applications, this study presents a numerical work focusing on the impacts of BCs on the natural convection of molten phase change material (PCM) used for cooling of photovoltaics (PV). A rectangular enclosure loaded with liquid PCM (Pr = 41.22) is considered at an inclination angle of θ = 30° to simulate a PV‐PCM system. Heat flux is applied to the top wall, and impacts of two different BCs at the bottom wall, namely isothermal and convective BCs, on the flow and heat transfer characteristics are compared by taking six different Biot numbers (0.1 ≤ Bi ≤ 100) into account, while the reference case is considered as isothermal BC. Furthermore, the effects of various aspect ratios (AR = 1, 2 and 4) and Rayleigh numbers (Ra = 104, 105 and 106) are also included. The results revealed that Biot number has a significant effect on mean Nusselt number. Compared to the isothermal case, low Biot numbers (Bi < 10) significantly restrict convection motions inside the enclosure and result in remarkably different mean Nusselt numbers, while high Biot numbers give significantly similar results due to low thermal resistance outside the bottom wall. Moreover, the heat transfer enhancement by increasing AR and Ra is considerably high at high Biot numbers, while it is remarkably constricted at low Biot numbers. As a result of comprehensive analyses, it is deduced that utilization of isothermal BCs instead of convective BC for easiness of modelling can be a reasonable approach providing that Biot number is sufficiently large (Bi > 10). Although the inspiration of the present study is PV/PCM systems, the results can be generalized for any kind of fluids used in similar natural convection applications.

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Numerical and experimental study on temperature control of solar panels with form-stable paraffin/expanded graphite composite PCM

Cited by 149 publications

References 32 publications

Promoting Energy Efficiency via a Self‐Adaptive Evaporative Cooling Hydrogel

Promoting Energy Efficiency via a Self‐Adaptive Evaporative Cooling Hydrogel

Evaluation of New PCM/PV Configurations for Electrical Energy Efficiency Improvement through Thermal Management of PV Systems

Implications of boundary conditions on natural convective heat transfer of molten phase change material inside enclosures

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