iScience
·
2022
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IF 6.107
Jiliang Zhu,Zhiqiang An,Anxun Zhang,Yike Du,Xuan Zhou,Yizhao Geng,Guifeng Chen
Porous polymer radiative cooling coatings (PPCs) have attracted attention due to their ability of drawing and radiating heat from a hot object into the outer space, without any energy consumption. However, high performance of PPCs has yet to be achieved and the large-scale production of radiative cooling technology is still facing high cost and complex manufacturing constraints. Here, we propose a simple, inexpensive, scalable approach to fabricate anisotropic (P(VdF-HFP)) ap PPCs (TPCs) by dissolution and diffusion between solvent and non-solvent-induced phase separation. By adjusting the porosity, pore size, and geometry, a sub-ambient temperature drop of ∼6.3°C in daytime and 10.1°C in night-time was achieved under a solar reflectance of 0.92 and an atmospheric window emittance of 0.96. A thermoelectric generator with an output voltage of almost zero reached 7 V/m 2 after coating with TPCs. This could provide a convenient, economical, and environment-friendly way for PPCs materials toward efficient cooling and power generations.
研究领域:
材料科学
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环境科学
✓ 已验证
DOI
高影响因子
Journal of the American Chemical Society
·
2024
·
IF 14.4
Bingjie Wang,Xinyang Liu,Fengxia Hu,Jian-tao Wang,Junsen Xiang,Peijie Sun,Jing Wang,Jirong Sun,Tongyun Zhao,Zhaojun Mo,Jun Shen,Yunzhong Chen,Qingzhen Huang,Baogen Shen
Adiabatic demagnetization refrigeration (ADR) based on the magnetocaloric effect (MCE) is a promising technique to achieve cryogenic temperature. However, magnetic entropy change (ΔSM), the driving force of ADR, remains far below theoretical −ΔSM = nRln(2J + 1)/MW for most magnetic refrigerants. Here, we report giant MCE in orthorhombic EuCl2, where a ferromagnetic ground state with excellent single-ion behavior of Eu2+ and free spins has been demonstrated by combining ab initio calculations with Brillouin function analysis and magnetic measurements. Consequently, a record-high −ΔSM ∼ 74.6 J·kg–1·K–1 (1.8 K) at 5 T was experimentally achieved, approaching 96% of the theoretical limit (77.5 J·kg–1·K–1). At a lower field of 1 T, EuCl2 also achieves the highest-ever record of −ΔSM ∼ 36.8 J·kg–1·K–1. Further, direct quasi-adiabatic demagnetization measurements demonstrate that its large −ΔSM allows EuCl2 to maintain a long holding time at sub-Kelvin temperature (∼346 mK), surpassing all previously reported materials. These superior magnetocaloric performances position EuCl2 as an attractive cryogenic refrigerant.
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
International Journal of Refrigeration
·
2021
·
IF 3.629
Zhenghao Jin,Shuhong Li,Runfa Zhou,Mengkai Xu,Weixue Jiang,Kai Du
The newly NH 3 – H 2 O – LiBr working fluid can decrease the power wasted in the generator, thus improves the COP of the ammonia absorption refrigeration system. But the applying of NH 3 – H 2 O – LiBr working fluid decreases the ammonia absorption efficiency, so the COP of the system is still unsatisfactory. To further enhance the COP of the NH 3 – H 2 O - LiBr absorption refrigeration system, TiO 2 nanoparticles are added to the NH 3 – H 2 O - LiBr working fluid in this study. And the effects of TiO 2 nanoparticles concentration on the performances of the generator, absorber, evaporator, condenser, and solution heat exchanger are tested in an ARS experimental system. The experimental results indicate that the addition of TiO 2 nanoparticles increases the P g , P e , P a , and P c , meaning that the value of ammonia produced in the generator increases. Therefore, the COP and iCOP of the system are improved by adding TiO 2 nanoparticles, and the COP is maximum improved by 18.96% compared with the ammonia-water absorption refrigeration system. When the x TiO2 is increased from 0.3% to 0.5%, the increase rate of the COP decreases because the newly added nanoparticles do not disperse well. So 0.3% is a better choice for the TiO 2 nanoparticles concentration when comprehensively considering the dispersion stability of nanoparticles and the COP.
研究领域:
工程热物理
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制冷技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
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IF 6.371
Huicai Xie,Quanyi Liu,Xiaohua Luo,Shengcan Ma,Xinqiang Gao,Zhenxing Li,Zhaojun Mo,Jun Shen
For more practical applications, research on magnetic refrigeration has been gradually focused on developing refrigerants with large magnetocaloric effect (MCE) under low magnetic fields (≤2 T). EuTiO 3 exhibits considerable low-field MCE near ordering temperature, meanwhile the magnetic switch from antiferromagnetic to ferromagnetic (AFM-FM) in it provides the feasibility of improving the magnetocaloric performance. In this study, a series of Eu(Ti,Nb,M)O 3 (M=Cu or Zn) compounds were synthesized, and the crystal structure, magnetic properties together with cryogenic MCEs were investigated in detail. The co-substitution contributes to an FM coupling domination in all the compounds. Besides, significantly enhanced and giant low-field MCEs were detected in these compounds. Under the field change of 1 T, all the samples possess remarkable magnetic entropy change (>15 J·kg -1 ·K -1 ) around 5 K without hysteresis. The corresponding refrigerating capacities are calculated to be 68.0, 72.6, 76.0, and 69.6 J·kg -1 , respectively, exhibiting an increase of 149–178% than EuTiO 3 . The outstanding magnetocaloric performances make the Eu(Ti,Nb,M)O 3 (M=Cu or Zn) compounds competitive candidates for cryogenic magnetic refrigeration.
研究领域:
材料科学
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凝聚态物理
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功能材料
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低温工程
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磁学
✓ 已验证
DOI
高影响因子
APPLIED THERMAL ENGINEERING
·
2025
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IF 6.9
Yufan Yang,Chunhuan Luo,Chunting Zhou,Muran He
To enhance the performance of low-temperature proton exchange membrane fuel cells (LT-PEMFC) and meet cooling demands, this study proposes an absorption-compression cycle using R1336mzz(Z)/TEGDME as the working pair, coupled with LT-PEMFC. The thermal properties of this working pair, including saturation vapor pressure and specific heat capacity, were measured and regressed, while the mixing enthalpy and specific enthalpy were calculated using the NRTL model. Based on the obtained thermal properties, MATLAB simulations were performed to evaluate the performance of the coupled system under varying operating conditions representative of both winter and summer environments. The results indicate that this coupled system can effectively utilize the low-temperature waste heat generated by LT-PEMFC to provide cooling at −20 °C. When LT-PEMFC produces 60 kW of usable electric power, the cooling capacity can reach 32.5 kW in winter and 60.1 kW in summer. Under typical winter and summer operating conditions, the coefficient of performance of the coupled system is approximately 0.73, representing a 9 % improvement over the compression cycle and a 65.5 % increase compared to the standalone LT-PEMFC, which is significant for enhancing vehicle performance.
研究领域:
能源工程
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热力学
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燃料电池技术
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITE INTERFACES
·
2025
·
IF 2.4
Zhenyu Zhu,Xinxing Nie,Yuheng Fu,Yibo Zhang,Zhiwei Ye,Hongmei Qin,Chuanxi Xiong,Shixian Zhang
With the increasing demand for refrigeration in modern society, the environmental costs associated with traditional vapor compression refrigeration have become increasingly significant. In this context, polymer elastomers based on the elastocaloric effect have emerged as a promising alternative due to their high energy efficiency, ease of processing, and low cost. However, the elastocaloric response of current polymer elastomers still falls short of practical application levels, and effective methods to enhance the elastocaloric effect are lacking. Here, we investigated the elastocaloric effect of poly(styrene-b-ethylene-co-butylene-b-styrene) (SEBS) based composites from the perspective of conformational changes through in situ testing. We demonstrated that the introduction of SiO2 increases the conformational entropy of the composites in the relaxed state while reducing it in the stretched state, resulting in greater conformational changes during deformation. With the optimal composition, the adiabatic temperature change of the composites reached −16 K, and the isothermal entropy change reached 163.1 J kg−1 K−1, representing a 30% improvement compared to SEBS. This study provides a novel approach for enhancing the elastocaloric effect of polymer elastomers, potentially advancing the commercialization of polymer-based elastocaloric refrigeration.
研究领域:
材料科学
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能源技术
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高分子化学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2024
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IF 13.3
Jun-Heng Fu,Qigong Zhang,Minglei Yan,Wei Tang,Yun Zeng,Yuntao Cui,Mingkuan Zhang,Hongwei Deng,Hao Kang,Xinlong Sun,Liang Qiao,Hongzhang Wang,Yang Zhao
Passive radiative cooling which dissipates heat from surfaces by reflecting sunlight and emitting radiation towards outer space, has garnered growing attention as an eco-friendly cooling strategy with zero-energy consumption. However, few studies focus on low-cost and multifunctional composite film fabricated by a straightforward and environmentally friendly method that is crucial for their large-scale applications. Herein, we introduce a facile, efficient, and scalable approach to fabricate a hydrophobic and polymer-dielectric poly (vinylidene fluoride)-hexafluoropropylene (P(VDF-HFP)@PVA hydrogel Janus film (DPP), exhibiting exceptional radiative cooling and thermal management capabilities for diverse practical applications. With the introduction of ZnO, DPP showcases the optical capability with a solar reflectance of ≈93 % and an infrared emittance of ≈96 %, endowing it with remarkable radiative cooling performance. The synergistic integration of hydrogel phase change and radiation cooling capabilities offered by the P(VDF-HFP) layer enables the DPP to achieve a subambient cooling of 8.62 °C under direct sunlight. Moreover, when applied to the thermal management of electronic devices and fruit preservation due to the phase change property, the DPP effectively reduced surface temperatures by 10 °C and 15.5 °C respectively. Its simplicity and versatility suggest that it could be widely adopted for daytime passive radiation cooling, thereby expanding its practical applications across various fields.
研究领域:
材料科学
·
能源与环境科学
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Physics
·
2024
·
IF 10
Yulong Qiao,Mengyang Wang,Hewei Ding,Jin Li,Junmei Zhang,Guiguang Qi,Xiongbo Yang,Xinyu Tan
When using high-power devices outdoors, especially in sunny summers, power losses coupled with direct sunlight can cause devices to overheat. This overheating not only disrupts their normal functioning but also increases the risk of fire accidents. To address this issue, the flexible polyvinylidene fluoride (PVDF)/strontium titanate (SrTiO 3 , denoted as ST) composite films (abbreviated as P-S-x where x represents the mass ratio of PVDF to ST, x = 0.5, 1, 1.5, 1.75) were developed through a simple mixing method. Outdoor Radiant Cooling tests demonstrate that the P-S-1.75 sample exhibits an average cooling effect ∼14.2 °C compared with pure PVDF sample and an average cooling effect ∼20.2 °C compared with a bare Al sample. The P-S-1.75 sample with a thickness of 115 μm achieves exceptional performance in the broadband mid-infrared range from 2.5 to 25 μm with an average emissivity reaching about 97 %. And the max reflectance of P-S-1.75 sample reaches 90 % in the range of 0.5–2.0 μm. Furthermore, P-S-1.75 sample obtains a thermal conductivity ∼1.97 W/(m·K) which is about ten times higher than that of pure PVDF (0.2 W/(m·K)), and a cooling effect of 11.7 °C on the ceramic heating plate was obtained. The outstanding cooling performance exhibited by P-S-1.75 coating can be attributed to its exceptional radiative cooling capacity and high thermal conductivity. This work provides a new idea to obtain polymer/ceramic composite materials with excellent radiative cooling performance in cooling applications.
研究领域:
材料科学
·
能源工程
·
热管理技术
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Physics
·
2025
·
IF 9.7
Jiwei Yao,Weijun Ren,Qing Guo,Peng Liu,Ziqi Guan,Changjiang Bao,Zhenquan Zhang,Dan Huang,Kun Zhang,Yanxu Wang,Dongliang Zhao,Jun He,Bing Li
Magnetic refrigeration is a promising technology capable of achieving sub-Kelvin temperatures without using 3 He. However, conventional magnetocaloric materials suffer from drawbacks such as high driving magnetic fields, low magnetic entropy change (Δ S M ), and structural instability, limiting their practical application. In this work, KGdF 4 with different crystal structures was synthesized, and the structure dependence of the magnetocaloric effect (MCE) was investigated. Notably, in the cubic KGdF 4 (C-KGdF 4 ), the chemical disorder of Gd 3+ /K + , increases the Gd 3+ -Gd 3+ distance and weakens the dipolar interactions, and thus leads to a large -Δ S M = 30.5 J kg −1 K −1 at 1.3 K at the magnetic field change of 10 kOe, which is more than three times of that of the commercial Gadolinium Gallium Garnet (Gd 3 Ga 5 O 12 , GGG) under the same conditions. Furthermore, the magnetic ordering temperature of 0.6 K of the C-KGdF 4 is lower than most reported Gd-based magnetocaloric materials. These excellent magnetocaloric performances suggest that C-KGdF 4 is a highly promising candidate for ultra-low-temperature magnetic refrigeration.
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
高影响因子
ENERGY
·
2021
·
IF 7.147
Xiao Zhang,Liang Cai,Tao Chen,Jingyi Qiao,Xiaosong Zhang
This research aims to develop novel binary working pairs using low-GWP refrigerants (R32, R152a, or R161) and one chemical absorbent (DMETEG) for absorption refrigeration systems . The solubility data were determined from 293.15 to 343.15 K using a static method and were correlated with the five-parameter non-random two-liquid (NRTL) activity coefficient model with an average relative absolute error of <2.4%. All three binary mixtures exhibited negative deviations from Raoult’s law. DMETEG was further assessed with other organic solvents that were previously measured to verify its highest affinity with HFCs. Based on the obtained VLE data, the thermodynamic performances in both the single-stage absorption refrigeration system (ARS) and the absorption-compression hybrid refrigeration system (ACHRS) were assessed. R161 yielded the highest cooling COP of 0.519–0.555 when the generation temperature was above 135 °C, followed by the R152a at 0.231–0.518 when below 135 °C. Different from the trends of COP variations, R152a had the highest ECOP of 0.091–0.158 when the generation temperature was below 135 °C while R161 showed the highest ECOP of 0.116–0.137 over 135 °C. ACHRS can effectively enhance the cooling performances of ARS via compression and its compression ratios got optimized. Overall, the R161 + DMETEG showed the best potential as the working pair.
研究领域:
化学工程
·
制冷技术
✓ 已验证
产品关联
DOI
高影响因子
POLYHEDRON
·
2022
·
IF 2.975
Na Qiao,Xiao-Xiao Li,Ying Chen,Xiao-Yan Xin,Chen Yang,Shan-Shan Dong,Yan-Zi Wang,Xing-Jin Li,Yu-Peng Hua,Wen-Min Wang
Three dinuclear Ln 2 compounds, [Ln 2 (dbm) 4 (L - ) 2 ]·4CH 3 CN (Ln = Gd ( 1 ), Tb ( 2 ), Dy ( 3 ), HL = (E)-N'-(2-hydroxybenzylidene)benzohydrazide and dbm = dibenzoylmethane), have been obtained by a solvent evaporation method. The structural analyses indicate that the three Ln 2 compounds (Gd 2 , Tb 2 and Dy 2 ) are isostructural with a Ln 2 O 2 center. Magnetic investigations show the presence of magnetic refrigeration in the Gd-based compound with a -ΔS m value of 17.62 J kg −1 K −1 ( T = 2.0 K and Δ H = 7.0 T); for compound 3 , however, single-molecular magnet behavior (SMM) was observed ( U eff /k B = 0.84 K and τ 0 = 1.08 × 10 −5 s).
研究领域:
化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
·
IF 6.371
Quanyi Liu,Junfeng Wang,Huicai Xie,Qi Fu,XinQiang Gao,Zhenxing Li,JinLiang Zhao,Zhaojun Mo
A modified solid-phase reaction method was used to synthesize the polycrystalline Eu 3 B 2 O 6 -as a novel cryogenic magnetocaloric material. In addition, investigations into the magnetocaloric effect (MCE), magnetic properties and crystal structure of compound have been precisely completed. The results indicate that the compound undergoes a second-order magnetic-phase transition from ferromagnetic to paramagnetic at 8 K and has a hexagonal structure that belongs to the R-3c space group. Meanwhile, the MCE was evaluated by using magnetic entropy change (-Δ S M ), temperature averaged entropy change ( TEC ) as well as the refrigeration capacity ( RC ) for Eu 3 B 2 O 6 . Under the field change from 0 to 5 T, the maximal values of -Δ S M and TEC (5) are 38.6 and 35.7 J kg −1 K −1 , respectively, while the corresponding RC reaches 435.9 J kg −1 . The giant low-field MCE facilitates device miniaturization and cost reduction, making Eu 3 B 2 O 6 compound a promising candidate for cryogenic magnetic refrigeration.
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）