{"title":"Improving efficiency of non-fullerene polymer solar cells by using non-halogenated solvents","authors":"K. An, Lei Ying, Fei Huang, Yong Cao","doi":"10.1117/12.2602631","DOIUrl":"https://doi.org/10.1117/12.2602631","url":null,"abstract":"","PeriodicalId":16781,"journal":{"name":"Journal of Photonics for Energy","volume":"11 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2021-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84279295","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. The efficiency and performance of solar cells and modules are typically evaluated and reported at normal incidence under peak solar radiation. We present a simple clear-sky model for solar irradiance that can be used to study the angular and annual performance of new photovoltaic materials. Using this model, we study the effect of solar module orientation for fixed-tilt module installations and different types of tracking (seasonal, 1D, and 2D) as a function of latitude. For fixed-tilt modules, the optimum tilt as a fraction of latitude varies from 0.83 at 1 deg to 0.73 at 60 deg. The effect of tilt misorientation for panels at the optimum azimuth is not very strong as the solar irradiance is about 94.5% of its optimum at ±20 deg mistilt. Both azimuth misorientation and tilt misorientation are studied. Optimized tilts and times of year for tilting are also obtained for modules that are seasonally adjusted twice and three times a year. The annual solar insolation of fixed modules is compared with modules that are seasonally adjusted twice and three times a year, continuously tracked in the north/south direction, continuously tracked in the east/west direction, and continuously tracked in two directions. The use of single-axis tracking in the east/west direction is preferable to north/south tracking and potentially improves overall energy collection by 16.2% to 31.0%. Continuous dual-axis tracking enhances overall annual energy collection by 36.0% to 45.5%. The model and provision of open source code provides for a way to assess the performance of new materials.
{"title":"Solar module orientation and tracking type performance and optimization","authors":"Sooraj Sharma, Paul W. Leu","doi":"10.1117/1.JPE.11.045501","DOIUrl":"https://doi.org/10.1117/1.JPE.11.045501","url":null,"abstract":"Abstract. The efficiency and performance of solar cells and modules are typically evaluated and reported at normal incidence under peak solar radiation. We present a simple clear-sky model for solar irradiance that can be used to study the angular and annual performance of new photovoltaic materials. Using this model, we study the effect of solar module orientation for fixed-tilt module installations and different types of tracking (seasonal, 1D, and 2D) as a function of latitude. For fixed-tilt modules, the optimum tilt as a fraction of latitude varies from 0.83 at 1 deg to 0.73 at 60 deg. The effect of tilt misorientation for panels at the optimum azimuth is not very strong as the solar irradiance is about 94.5% of its optimum at ±20 deg mistilt. Both azimuth misorientation and tilt misorientation are studied. Optimized tilts and times of year for tilting are also obtained for modules that are seasonally adjusted twice and three times a year. The annual solar insolation of fixed modules is compared with modules that are seasonally adjusted twice and three times a year, continuously tracked in the north/south direction, continuously tracked in the east/west direction, and continuously tracked in two directions. The use of single-axis tracking in the east/west direction is preferable to north/south tracking and potentially improves overall energy collection by 16.2% to 31.0%. Continuous dual-axis tracking enhances overall annual energy collection by 36.0% to 45.5%. The model and provision of open source code provides for a way to assess the performance of new materials.","PeriodicalId":16781,"journal":{"name":"Journal of Photonics for Energy","volume":"11 1","pages":"045501 - 045501"},"PeriodicalIF":1.7,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49051182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Meijie Chen, Shuang Li, Dan Pang, Yanwei Zhao, Yuan Yang, Hong-jie Yan
Abstract. Dielectric microsphere coatings for passive daytime radiative cooling (PDRC) are gaining attention owing to their low cost and potential for mass production. The cooling performance could be further enhanced to effectively reflect solar radiation and emit thermal radiation to the cold sky by designing microspheres suitable for PDRC applications. Hollow dielectric structures were numerically designed to enhance the PDRC performance of dielectric microsphere coatings. The maximum solar reflectance (R¯solar = 0.96) was obtained with a fill rate f = 0.6, outer radius rout = 0.5 μm, core–shell rate φ = rin / rout = 0.3, thickness t = 300 μm, and thermal infrared emittance ε¯LWIR = 0.90. Furthermore, by controlling the multisize sphere distribution within φ = 0.1 to 0.5, the cooling performance at t = 300 μm was enhanced to R¯solar = 0.98, ε¯LWIR = 0.95, and a net cooling power of 77 W / m2 was achieved at a temperature of 25°C, which was ∼38 % higher than that achieved with the single-size sphere coating (φ = 0.3) and ∼64 % higher than that of the solid SiO2 sphere coating (φ = 0). These results indicate that hollow structures can effectively enhance the cooling performance of dielectric microsphere coatings by increasing the number of interfaces between the air and dielectric materials.
{"title":"Numerically enhancing daytime radiative cooling performance of random dielectric microsphere coatings by hollow structures","authors":"Meijie Chen, Shuang Li, Dan Pang, Yanwei Zhao, Yuan Yang, Hong-jie Yan","doi":"10.1117/1.JPE.11.042108","DOIUrl":"https://doi.org/10.1117/1.JPE.11.042108","url":null,"abstract":"Abstract. Dielectric microsphere coatings for passive daytime radiative cooling (PDRC) are gaining attention owing to their low cost and potential for mass production. The cooling performance could be further enhanced to effectively reflect solar radiation and emit thermal radiation to the cold sky by designing microspheres suitable for PDRC applications. Hollow dielectric structures were numerically designed to enhance the PDRC performance of dielectric microsphere coatings. The maximum solar reflectance (R¯solar = 0.96) was obtained with a fill rate f = 0.6, outer radius rout = 0.5 μm, core–shell rate φ = rin / rout = 0.3, thickness t = 300 μm, and thermal infrared emittance ε¯LWIR = 0.90. Furthermore, by controlling the multisize sphere distribution within φ = 0.1 to 0.5, the cooling performance at t = 300 μm was enhanced to R¯solar = 0.98, ε¯LWIR = 0.95, and a net cooling power of 77 W / m2 was achieved at a temperature of 25°C, which was ∼38 % higher than that achieved with the single-size sphere coating (φ = 0.3) and ∼64 % higher than that of the solid SiO2 sphere coating (φ = 0). These results indicate that hollow structures can effectively enhance the cooling performance of dielectric microsphere coatings by increasing the number of interfaces between the air and dielectric materials.","PeriodicalId":16781,"journal":{"name":"Journal of Photonics for Energy","volume":"11 1","pages":"042108 - 042108"},"PeriodicalIF":1.7,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46131055","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. The quality of the perovskite film highly affects the performance of perovskite solar cells (PSCs). To deposit uniform and dense perovskite films, the fabrication processes are usually conducted in a controlled environment such as a glove box, which limits the future commercial development. High-quality perovskite films were fabricated in high humidity using mixed antisolvent consisting of ethyl acetate (EA) and diethyl ether (DE). It is found that the speed of perovskite crystallization could be controlled by adjusting the volume ratio of EA and DE in the mixed antisolvent, enhancing the grain size of perovskite films. The PSC fabricated in a humidity of 70% treated with an optimal ratio EA and DE exhibits an enhanced efficiency of 18.77% from 11.07%. Our work provides a convenient strategy for fabricating highly efficient PSCs in a high-humidity environment.
{"title":"Highly efficient perovskite solar cells fabricated in high humidity using mixed antisolvent","authors":"Jun He, Shengyu Jiang, Shunmin Ding, Minlin Jiang","doi":"10.1117/1.JPE.11.045502","DOIUrl":"https://doi.org/10.1117/1.JPE.11.045502","url":null,"abstract":"Abstract. The quality of the perovskite film highly affects the performance of perovskite solar cells (PSCs). To deposit uniform and dense perovskite films, the fabrication processes are usually conducted in a controlled environment such as a glove box, which limits the future commercial development. High-quality perovskite films were fabricated in high humidity using mixed antisolvent consisting of ethyl acetate (EA) and diethyl ether (DE). It is found that the speed of perovskite crystallization could be controlled by adjusting the volume ratio of EA and DE in the mixed antisolvent, enhancing the grain size of perovskite films. The PSC fabricated in a humidity of 70% treated with an optimal ratio EA and DE exhibits an enhanced efficiency of 18.77% from 11.07%. Our work provides a convenient strategy for fabricating highly efficient PSCs in a high-humidity environment.","PeriodicalId":16781,"journal":{"name":"Journal of Photonics for Energy","volume":"11 1","pages":"045502 - 045502"},"PeriodicalIF":1.7,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44045807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. We demonstrate switchable polarized thermal emission from VO2 nanofin stacks fabricated by co-deposition, etching, and oxidation. We find that reverse switching of the thermal emission is enabled by a reflecting underlayer and induced by either short oxidation time or additional deposition of a reflecting underlayer. Observed thermal emission is well explained by a biaxial Bruggeman effective medium model, which predicts the strong polarization change for aligned fin layers in the micron thickness range. The dominant polarization of the emission is modulated by the presence of a reflector, oxidation of the fins, fin fill-factor, and structural anisotropy. Normal incidence polarized emittance change of up to 0.6 is theoretically possible, and we were able to demonstrate a change of 0.34, similar to that predicted by the model.
{"title":"Dynamic control of polarized thermal emission from VO2 nanofins","authors":"Caleb Estherby, M. Arnold, M. Tai, A. Gentle","doi":"10.1117/1.JPE.11.042111","DOIUrl":"https://doi.org/10.1117/1.JPE.11.042111","url":null,"abstract":"Abstract. We demonstrate switchable polarized thermal emission from VO2 nanofin stacks fabricated by co-deposition, etching, and oxidation. We find that reverse switching of the thermal emission is enabled by a reflecting underlayer and induced by either short oxidation time or additional deposition of a reflecting underlayer. Observed thermal emission is well explained by a biaxial Bruggeman effective medium model, which predicts the strong polarization change for aligned fin layers in the micron thickness range. The dominant polarization of the emission is modulated by the presence of a reflector, oxidation of the fins, fin fill-factor, and structural anisotropy. Normal incidence polarized emittance change of up to 0.6 is theoretically possible, and we were able to demonstrate a change of 0.34, similar to that predicted by the model.","PeriodicalId":16781,"journal":{"name":"Journal of Photonics for Energy","volume":"11 1","pages":"042111 - 042111"},"PeriodicalIF":1.7,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45672005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Daytime radiative cooling technology can cool objects to sub-ambient temperatures under direct sunlight without energy consumption. The technology relies on high reflectance of solar irradiation and high emissivity in the atmospheric window (infrared emission with 8 to 13 μm wavelengths). We report a bilayer structured coating for passive daytime sub-ambient radiative cooling. The bilayer radiative cooling coating has high solar reflectance (0.94), and high infrared emissivity (0.96) in the atmospheric window. The bilayer coating achieved a sub-ambient temperature of 3.6°C under solar irradiance of 990 W / m2 at an ambient temperature of 26.6°C, and the averaged sub-ambient cooling temperature of ∼8 ° C during the night. A test with two model rooms shows that the indoor air temperature reached a maximum difference of 9.7°C between the one with the bilayer coating and that with normal white coating.
摘要日间辐射冷却技术可以在阳光直射下将物体冷却到低于环境温度，而无需能耗。该技术依赖于太阳辐射的高反射率和大气窗口的高发射率（波长为8-13μm的红外发射）。我们报道了一种用于被动日间亚环境辐射冷却的双层结构涂层。双层辐射冷却涂层在大气窗口中具有高太阳反射率（0.94）和高红外发射率（0.96）。双层涂层在990的太阳辐照度下达到3.6°C的亚环境温度 W / m2，环境温度为26.6°C，平均亚环境冷却温度为~8 ° C在晚上。对两个模型室的测试表明，双层涂层和普通白色涂层的室内空气温度之间的最大差值为9.7°C。
{"title":"Bilayer structured coating for radiative cooling applications","authors":"Rongbing Wan, Zhihao Ma, Weiping Xu, Wenbo Zhao, Jingtao Xu, Ronggui Yang","doi":"10.1117/1.JPE.11.042109","DOIUrl":"https://doi.org/10.1117/1.JPE.11.042109","url":null,"abstract":"Abstract. Daytime radiative cooling technology can cool objects to sub-ambient temperatures under direct sunlight without energy consumption. The technology relies on high reflectance of solar irradiation and high emissivity in the atmospheric window (infrared emission with 8 to 13 μm wavelengths). We report a bilayer structured coating for passive daytime sub-ambient radiative cooling. The bilayer radiative cooling coating has high solar reflectance (0.94), and high infrared emissivity (0.96) in the atmospheric window. The bilayer coating achieved a sub-ambient temperature of 3.6°C under solar irradiance of 990 W / m2 at an ambient temperature of 26.6°C, and the averaged sub-ambient cooling temperature of ∼8 ° C during the night. A test with two model rooms shows that the indoor air temperature reached a maximum difference of 9.7°C between the one with the bilayer coating and that with normal white coating.","PeriodicalId":16781,"journal":{"name":"Journal of Photonics for Energy","volume":"11 1","pages":"042109 - 042109"},"PeriodicalIF":1.7,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46568133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lyu Zhou, Jacob Rada, Haomin Song, B. Ooi, Zongfu Yu, Qiaoqiang Gan
Abstract. Daytime radiative cooling has attracted extensive research interest due to its potential impact for energy sustainability. To achieve subambient radiative cooling during the daytime, a white surface that strongly scatters incident solar light is normally desired. However, in many practical applications (e.g., roofing materials and car coatings), colored surfaces are more popular. Because of this, there is a strong desire to develop colorful surfaces for radiative cooling. We summarize the general design criteria of radiative cooling materials with different colors and discuss the limitations in cooling performance. Major efforts on this specific topic are reviewed with some suggested topics for future investigation.
{"title":"Colorful surfaces for radiative cooling","authors":"Lyu Zhou, Jacob Rada, Haomin Song, B. Ooi, Zongfu Yu, Qiaoqiang Gan","doi":"10.1117/1.JPE.11.042107","DOIUrl":"https://doi.org/10.1117/1.JPE.11.042107","url":null,"abstract":"Abstract. Daytime radiative cooling has attracted extensive research interest due to its potential impact for energy sustainability. To achieve subambient radiative cooling during the daytime, a white surface that strongly scatters incident solar light is normally desired. However, in many practical applications (e.g., roofing materials and car coatings), colored surfaces are more popular. Because of this, there is a strong desire to develop colorful surfaces for radiative cooling. We summarize the general design criteria of radiative cooling materials with different colors and discuss the limitations in cooling performance. Major efforts on this specific topic are reviewed with some suggested topics for future investigation.","PeriodicalId":16781,"journal":{"name":"Journal of Photonics for Energy","volume":"11 1","pages":"042107 - 042107"},"PeriodicalIF":1.7,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44538801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. The history of quantitative measurements of radiative cooling is briefly reviewed, starting with Count Rumford in 1804. The cooling results from upward emission of thermal infrared radiation (wavelengths of 5 to 50 μm) that is not fully offset by downward atmospheric emission. The downward emission is characterized by the apparent atmospheric (sky) emittance and the surface air temperature. In 1984, an equation was published that describes the clear sky emittance as a function of the surface dew point temperature. At the time, this equation was merely one of many empirical relations. Now that time has passed, experimental and theoretical advances support its validity. Further refinements can include improved corrections for time-of-day and the lower air pressure at elevated locations. Complex computer codes for predicting atmospheric radiation have reached quantitative maturity. Given profiles of air temperature, water vapor, CO2, O3, CH4, N2O, and aerosols, they can compute spectral radiances with an accuracy of ∼3 % . The effect of clouds in reducing radiative cooling remains more uncertain.
{"title":"Retrospective on the resource for radiative cooling","authors":"P. Berdahl","doi":"10.1117/1.JPE.11.042106","DOIUrl":"https://doi.org/10.1117/1.JPE.11.042106","url":null,"abstract":"Abstract. The history of quantitative measurements of radiative cooling is briefly reviewed, starting with Count Rumford in 1804. The cooling results from upward emission of thermal infrared radiation (wavelengths of 5 to 50 μm) that is not fully offset by downward atmospheric emission. The downward emission is characterized by the apparent atmospheric (sky) emittance and the surface air temperature. In 1984, an equation was published that describes the clear sky emittance as a function of the surface dew point temperature. At the time, this equation was merely one of many empirical relations. Now that time has passed, experimental and theoretical advances support its validity. Further refinements can include improved corrections for time-of-day and the lower air pressure at elevated locations. Complex computer codes for predicting atmospheric radiation have reached quantitative maturity. Given profiles of air temperature, water vapor, CO2, O3, CH4, N2O, and aerosols, they can compute spectral radiances with an accuracy of ∼3 % . The effect of clouds in reducing radiative cooling remains more uncertain.","PeriodicalId":16781,"journal":{"name":"Journal of Photonics for Energy","volume":"11 1","pages":"042106 - 042106"},"PeriodicalIF":1.7,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43792566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. The erratum corrects the affiliations listed in the originally published article.
摘要勘误表更正了最初发表的文章中列出的从属关系。
{"title":"Erratum: Performance enhancement of ultrathin graded Cu(InGa)Se2 solar cells through modification of the basic structure and adding antireflective layers","authors":"M. Amiri, A. Eskandarian, A. A. Ziabari","doi":"10.1117/1.jpe.11.049901","DOIUrl":"https://doi.org/10.1117/1.jpe.11.049901","url":null,"abstract":"Abstract. The erratum corrects the affiliations listed in the originally published article.","PeriodicalId":16781,"journal":{"name":"Journal of Photonics for Energy","volume":"11 1","pages":"049901 - 049901"},"PeriodicalIF":1.7,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45912259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Leroy, B. Bhatia, U. T. Njike, Geoffrey Vaartstra, E. Wang
Abstract. Optically selective and thermally insulating (OSTI) covers, such as polyethylene aerogels (PEAs), have recently been proposed to improve subambient daytime radiative cooling performance by minimizing parasitic solar absorption and heat gain at the emitter. We investigate the addition of zinc sulfide (ZnS) nanoparticles inside PEAs to improve their optical selectivity. Solving for multiple scattering effects using the radiative transfer equation and Mie theory, we model the optical properties of PEA covers with different ZnS concentrations and particle diameters. Our theoretical and experimental results show that ZnS particles inside PEAs can significantly reduce solar transmittance (<0.01) while maintaining high infrared transmittance (>0.8). Our modeling also demonstrates that ZnS-pigmented PEA covers enable higher subambient cooling powers (up to 53.8 W / m2 higher) and lower stagnation temperatures than conventional PEA under direct solar radiation (1000 W / m2). Finally, we investigate spatial distribution of ZnS within the cover and show that confining the ZnS near the air–cover boundary can reduce the total ZnS mass required by 59% or can enable 4% higher cooling power. Our findings promise to improve the performance of subambient radiative coolers and enable their application in passive cooling of buildings and refrigeration of food produce.
摘要光学选择性和隔热（OSTI）覆盖物，如聚乙烯气凝胶（PEA），最近被提出通过最小化发射器处的寄生太阳能吸收和热增益来改善亚环境日间辐射冷却性能。我们研究了在PEA中添加硫化锌（ZnS）纳米颗粒以提高其光学选择性。利用辐射传输方程和Mie理论求解多重散射效应，我们对不同ZnS浓度和粒径的PEA覆盖层的光学性质进行了建模。我们的理论和实验结果表明，PEA中的ZnS颗粒可以显著降低太阳透过率（0.8）。我们的模型还表明，ZnS着色的PEA覆盖物可以实现更高的亚环境冷却功率（高达53.8 W / m2更高）和比直接太阳辐射下的传统PEA更低的停滞温度（1000 W / m2）。最后，我们研究了ZnS在覆盖层内的空间分布，并表明将ZnS限制在空气-覆盖层边界附近可以将所需的总ZnS质量减少59%，或者可以使冷却功率提高4%。我们的发现有望提高亚环境辐射冷却器的性能，并使其能够应用于建筑物的被动冷却和食品冷藏。
{"title":"Zinc sulfide-pigmented polyethylene aerogel covers for daytime radiative cooling","authors":"A. Leroy, B. Bhatia, U. T. Njike, Geoffrey Vaartstra, E. Wang","doi":"10.1117/1.JPE.11.042110","DOIUrl":"https://doi.org/10.1117/1.JPE.11.042110","url":null,"abstract":"Abstract. Optically selective and thermally insulating (OSTI) covers, such as polyethylene aerogels (PEAs), have recently been proposed to improve subambient daytime radiative cooling performance by minimizing parasitic solar absorption and heat gain at the emitter. We investigate the addition of zinc sulfide (ZnS) nanoparticles inside PEAs to improve their optical selectivity. Solving for multiple scattering effects using the radiative transfer equation and Mie theory, we model the optical properties of PEA covers with different ZnS concentrations and particle diameters. Our theoretical and experimental results show that ZnS particles inside PEAs can significantly reduce solar transmittance (<0.01) while maintaining high infrared transmittance (>0.8). Our modeling also demonstrates that ZnS-pigmented PEA covers enable higher subambient cooling powers (up to 53.8 W / m2 higher) and lower stagnation temperatures than conventional PEA under direct solar radiation (1000 W / m2). Finally, we investigate spatial distribution of ZnS within the cover and show that confining the ZnS near the air–cover boundary can reduce the total ZnS mass required by 59% or can enable 4% higher cooling power. Our findings promise to improve the performance of subambient radiative coolers and enable their application in passive cooling of buildings and refrigeration of food produce.","PeriodicalId":16781,"journal":{"name":"Journal of Photonics for Energy","volume":"11 1","pages":"042110 - 042110"},"PeriodicalIF":1.7,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49128170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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