期刊：
Journal of Energy Storage,2023年59:106367 ISSN：2352-152X
通讯作者：
Chuanchang Li
作者机构：
[Li, Chuanchang; Xie, Baoshan] Changsha Univ Sci & Technol, Sch Energy & Power Engn, Changsha 410114, Peoples R China.;[He, Ya-Ling] Xi An Jiao Tong Univ, Sch Energy & Power Engn, Key Lab Thermo Fluid Sci & Engn, Minist Educ, Xian 710049, Shaanxi, Peoples R China.
通讯机构：
[Chuanchang Li] S;School of Energy and Power Engineering, Changsha University of Science and Technology, Changsha 410114, China
关键词：
Thermal energy storage;Phase change material;Microcrystalline graphite;Templated assembly technique;Electro-heat conversion
摘要：
Form-stable composite phase change material (PCM) with high latent heat is widely used in thermal energy storage application. The skeleton structure and thermophysical properties of the supporting material are greatly important to the energy efficiency of the composite PCM. This work is to design the supporting material with specific 3D carbon framework for composite PCMs using the CaCO3-templated assembly technique, following to explore the electro-heat conversion ability of composites. Microcrystalline graphite is used as the skeleton, CaCO3 as the template, and monocrystal white sugar as the carbon source. By designing the content of template, the 3D framework structure of supports can be tailored. Results show the designed support material has a higher cumulative pore volume than the raw material of 64 %, leading to an increment of the loading capacity of 12-20 %, due to the formation of the cotton-shaped carbonization connection products. Then, the stearic acid-type composite shows the thermal conductivity is improved by 104.86 % than the pure PCM, causing faster heat storage and release rate. At last, it proved that the electro-heat conversion of the composite can be achieved at low trigger voltage. The conversion efficiency increases with the voltage rising and the bulk density improving, reaching to 75.61 % at a voltage of 4.5 V with a bulk density of 0.774 g cmi 3.
关键词：
Mg-RE alloy;Hot tensile deformation;Microstructure;Fracture damage model
摘要：
Hot tensile tests are employed herein to explore the microstructural evolution and fracture damage of a hot-extruded Mg-9.1Y-1.8Zn (wt%) alloy at deformation temperatures of 250-400 degrees C and strain rates of 0.005-0.1 s(-1). The deformed microstructure and fracture morphology are systematically studied using electron backscatter diffraction (EBSD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The flow stress tends to decline with increasing tensile temperature or decreasing strain rate. Under all the tested conditions, discontinuous dynamic recrystallization (DDRX) is characterized by a bulged grain boundary and plays a critical role. Particle-stimulated nucleation (PSN) induced by the twisted long-period stacking ordered structure (LPSO) is another essential nucleation mechanism for DRX, especially at low strain rates. Since DRX is more straightforward at high temperatures, the fracture mechanism can be easily observed to change from intergranular to transcrystalline at tensile temperatures exceeding 250 degrees C. However, the effects of strain rate on the fracture mechanism seem inconspicuous at strains rates of 0.005-0.1 s(-1). Based on the Oyane-Sato criterion, a fracture damage model is established based on the experimental and numerically simulated results. The results signify that the developed damage model can accurately forecast fracture damage during hot tensile deformation, which is valuable for optimizing the hot forming processing of the tested Mg-RE alloy.
摘要：
The optimal control of heating, ventilation, and air-conditioning (HVAC) systems affects people's living and building energy consumption. Many studies have introduced personal thermal sensation into the air-conditioning system to reduce energy consumption while improving the indoor thermal environment. However, there are limitations that require multiple adjusted temperature settings to create a room thermal environment that meets personal thermal comfort needs, and the impact of room temperature set values on air-conditioning energy consumption is often ignored. This study proposes an indoor temperature preference setting control method (ITPSCM) for thermal comfort and energy saving based on reinforcement learning (RL), which uses personal thermal comfort and the energy-saving effect of the system as the reward function. Q-learning is employed to obtain optimized room temperature settings to meet users' temperature preferences. Several comparative experiments are carried out in an indoor environment control testbed, and the experimental data is used to train the RL algorithm. As the results show, compared with the temperature set value-based control method, the ITPSCM can realize an indoor thermal environment that meets personal thermal comfort preferences in the early stages of air-conditioning system operation. With just the thermal comfort as a reward, 22.34% of daily energy consumption can be saved; with both the thermal comfort reward and energy-saving effect reward are considered, 26.48% of daily energy consumption can be saved.
作者机构：
[Zhou, Jifei; Wen, Ke; He, Yecong; Sun, Jie] Changsha Univ Sci & Technol, Sch Energy & Power Engn, Changsha 410114, Peoples R China.;[Deng, Qi] TICA China Co Ltd, Nanjing 210046, Peoples R China.
会议名称：
International Conference on Smart Energy (ICSNRG)
会议时间：
SEP 17-18, 2022
会议地点：
ELECTR NETWORK
会议主办单位：
[Wen, Ke;He, Yecong;Sun, Jie;Zhou, Jifei] Changsha Univ Sci & Technol, Sch Energy & Power Engn, Changsha 410114, Peoples R China.^[Deng, Qi] TICA China Co Ltd, Nanjing 210046, Peoples R China.
会议论文集名称：
Journal of Physics Conference Series
摘要：
In order to explore the energy performance of a university building integrated with solar PV and energy storage, in this paper, DesignBuilder was used to establish the teaching building model and calculate the load based on the characteristics of the teaching building of a university, a simulation model of the photovoltaic & energy storage integrated system was built with TRNSYS. Then analysing the energy performance and economy of the system. The results show that, from the overall demand, the solar electricity generation capacity of the photovoltaic & energy storage integrated teaching building can basically meet the demand for air conditioning electricity, and there is more remaining electricity for the electricity grid. The energy performance of the system in different seasons (summer, spring and autumn transition season, winter) and the complementarity among various electric quantities are studied, including electricity consumption, electricity generation, municipal electricity supply, remaining electricity on grid, battery charge, battery discharge. The economic analysis of the system shows that Solar fraction (SF)=0.93, Self-Consumption Ratio (SCR)=0.13, Return on Investment (ROI)=0.219 years, Payback Period (PBP)=4.75 years, which proves its feasibility.
摘要：
Lubricant coating is an efficient method for preventing ice formation on the surface of wind turbine blades. However, lubricants are frequently lost during the freezing and deicing cycles, along with the migration of frost or ice. As a result, developing a lubricating anti-icing coating with high wear resistance and stability is critical for resolving the icing problem on fan blades. In this paper, 3-Aminopropyltriethoxysilane (KH-550) coupling agent was used to modify the nano-SiO2 particles to construct the micro-nano rough surface of the coating. Then, liquid paraffin lubricant was injected to obtain a new type of self-supplemented lubricating micro-nano composite coating, and its mechanical wear resistance and anti-icing performance were explored. The experimental results show that the contact angle of the liquid lubricating liquid micro-nano composite coating is still >105 degrees and the sliding angle is <15 degrees after 50 wear tests, showing good ice repellency, indicating that its wear resistance is enhanced. According to the standard ISO 2049, the mechanical adhesion reaches grade 0, showing good mechanical stability. The ice adhesion of the composite coating is 85.6% lower than that of the unlubricated sample, and the mechanical interlock between ice and the rough surface was greatly reduced. In comparison to the non-lubricating liquid coating, the micro-nano composite coating effectively extends the total freezing time of water droplets, reaching 821 s and demonstrating good anti-icing performance.
摘要：
The microstructure evolution of near p-Ti alloys with initially lamellar and equiaxed microstructures subjected to dynamic loading was investigated. Results showed that during high strain rate compression, shear failure is more likely to occur in equiaxed micro-structure. Owing to temperature rise and stress concentration, the lamellar a phase in adiabatic shear band (ASB) zone was recrystallized and re-melted, while the equiaxed a phase transformed in strip-shaped following the propagating direction of adiabatic shear band. During high strain rate loading, the twinning transfer was observed between p matrix and a phase, which demonstrates that twinning is the dominant deformation mode to accommodate plastic deformation.(c) 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
期刊：
Journal of Alloys and Compounds,2023年948:169720 ISSN：0925-8388
通讯作者：
Liwei Lu
作者机构：
[Lu, Liwei; Wei, Yuhui; Ma, Min; Li, Minhao] Hunan Univ Sci & Technol, Sch Mech Engn, Xiangtan 411201, Peoples R China.;[Wu, Ruizhi; Huang, Weiying; Lu, Liwei; Ma, Min] Hunan Jinfeng Mech Technol Co Ltd, Loudi 417700, Peoples R China.;[Huang, Weiying] Changsha Univ Sci & Technol, Sch Energy & Power Engn, Key Lab Efficient & Clean Energy Utilizat, Changsha 410114, Peoples R China.;[Zhao, Xi] North Univ China, Sch Aeronaut & Astronaut, Taiyuan 030051, Peoples R China.;[Wu, Ruizhi] Harbin Engn Univ, Key Lab Superlight Mat & Surface Technol, Minist Educ, Harbin 150001, Peoples R China.
通讯机构：
[Liwei Lu] S;School of Mechanical Engineering, Hunan University of Science and Technology, Xiangtan 411201, China<&wdkj&>Hunan Jinfeng Mechanical Technology Co., Ltd., Loudi 417700, China
关键词：
AZ31 magnesium alloy sheet;Forging -bending repeated deformation;Finite element method;Microstructure and hardness
摘要：
In this paper, a novel method of severe plastic deformation (SPD), i.e., forging-bending repeated de-formation process, was proposed to prepare AZ31 magnesium alloy sheets. The effects of the new process on the equivalent strain, flow rate, microstructure, and hardness at different passes were investigated by finite element method (FEM), electron backscatter diffraction (EBSD) and Zwick/roll hardness tester. The results showed that the effective strain and flow velocity increased with the increase of the pass. Due to the transition path, the shear deformation was sufficient at each position and the uniformity was improved. After 4 deformation passes, the refined grain size was 5.02 mu m on average. The dynamic recrystallization (DRX) mechanism in the first pass was discontinuous dynamic recrystallization (DDRX), and the interaction of twins-induced DRX and continuous dynamic recrystallization (CDRX) completed the microstructure evolution in the second pass. Meanwhile, {10-12} extension twins promoted the subsequent CDRX process by dividing coarse grains and changing grain orientation. In addition, slip-dominated pyramidal < c+a > slip was also committed to grain refinement, which can achieve high plasticity. Ultimately, the hardness of AZ31 magnesium alloy can reach 77.6HV after processing and deformation, and the grain size and high-density dislocation had significant effects on the distribution of hardness.(c) 2023 Elsevier B.V. All rights reserved.
摘要：
Jet injection technology has become the alternative drug delivery method of conventional needle-based injection due to its obvious advantages. In order to meet the demand for larger volume injection, the pneumatic jet injection systems have efficiently administrated vaccine up to 1mL in human. Our recent study has also demonstrated that controlling the driving pressure enabled the pneumatic jet injection system to deliver larger volumes of drugs to target sites at desired rates and times. This work continues to explore the optimal two-phase driving pressure combination with better injection efficiency for typical larger-volume (1.0mL) jet injection with controllable pneumatic jet injection system. Under the combination of a first phase driving pressure of 1.00MPa and a second phase driving pressure ranging from 0.25 to 0.90MPa, dynamic characteristics, dispersion characteristics and pharmacokinetic characteristics of this controllable jet injection system were quantitatively analyzed. In all experiments, it was confirmed that the optimal driving pressure combination of 1.0mL ejection volume was close to (1.00-0.50) MPa. That is, the injection velocities of 151.85m/s and 102.01m/s for the first and second phase respectively facilitated better injection performance with a controlled release of 1.0mL ejection volume. This strategy is practical for facilitating the clinical application of large-volume controllable jet injection systems.
作者机构：
[Mai, Yaohua; Yang, Yuzhao; Wu, Shaohang; Yu, Bohao] Jinan Univ, Inst New Energy Technol, Coll Informat Sci & Technol, Guangzhou 510632, Peoples R China.;[Yang, Yuzhao] Guangdong Univ Technol, Sch Chem Engn & Light Ind, Guangzhou 510006, Peoples R China.;[Lambertz, Andreas; Duan, Weiyuan; Ding, Kaining] Forschungszentrum Julich, IEK 5 Photovolta, D-52425 Julich, Germany.;[Tang, Fei; Lu, Feiping] Tianshui Normal Univ, Dept Phys, Tianshui 741000, Peoples R China.;[Huang, Jincheng] Changsha Univ Sci & Technol, Coll Energy & Power Engn, Changsha 410114, Peoples R China.
通讯机构：
[Yuzhao Yang; Shaohang Wu; Weiyuan Duan; Yaohua Mai] I;IEK-5 Photovoltaik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany<&wdkj&>Institute of New Energy Technology, College of Information Science and Technology, Jinan University, Guangzhou, 510632 China<&wdkj&>School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006 China<&wdkj&>Institute of New Energy Technology, College of Information Science and Technology, Jinan University, Guangzhou, 510632 China
关键词：
atomic deposition layer;buffer layer;perovskite solar cell;semi-transparent solar cell;tandem solar cell
摘要：
Abstract Atomic layer deposition (ALD) turns out to be particularly attractive technology for the sputtering buffer layer when preparing the semi‐transparent (ST) perovskite solar cells (PSCs) and the tandem solar cells. ALD process turns to be island growth when the substrate is unreactive with the ALD reactants, resulting in the pin‐hole layer, which causes an adverse effect on anti‐sputtering. Here, p–i–n structured PSCs with ALD SnOx as sputtering buffer layer are conducted. The commonly used electron transportation layer (ETL) PCBM in the p–i–n structured PVK solar cell is an unreactive substrate that prevents the layer‐by‐layer growth for the ALD SnOx. We activate PCBM layer by introducing reaction sites to form impermeable ALD layers. By introducing reaction sites/ALD SnOx as sputtering buffer layer, we succeed to fabricate ST‐PSCs and perovskite/silicon (double‐side polished) tandem solar cells with PCE of 20.25% and 23.31%, respectively. Besides, the unencapsulated device with reaction sites maintains more than 99% of the initial power conversion efficiency (PCE) after aging over 5100 hours. This work opens a promising avenue to prepare impermeable layer for stable PSCs, ST‐PSCs, tandem solar cells and the related scale‐up solar cells. This article is protected by copyright. All rights reserved
作者机构：
[Peng, Jinqing; Peng, JQ; Wang, Shuhao; Luo, Yimo] Hunan Univ, Coll Civil Engn, Changsha 410082, Hunan, Peoples R China.;[Peng, Jinqing; Wang, Shuhao; Luo, Yimo] Hunan Univ, Key Lab Bldg Safety & Energy Efficiency, Minist Educ, Changsha, Hunan, Peoples R China.;[Wang, Meng] Changsha Univ Sci & Technol, Sch Energy & Power Engn, Changsha 410114, Hunan, Peoples R China.;[Wang, Meng] Xian Univ Architecture & Technol, State Key Lab Green Bldg, Xian, Shanxi, Peoples R China.;[Zhao, Yifan; Xue, Peng] Beijing Univ Technol, Beijing Key Lab Green Built Environm & Efficient T, Beijing 100124, Peoples R China.
通讯机构：
[Peng, JQ ] H;[Wang, M ] C;Hunan Univ, Coll Civil Engn, Changsha 410082, Hunan, Peoples R China.;Changsha Univ Sci & Technol, Sch Energy & Power Engn, Changsha 410114, Hunan, Peoples R China.
关键词：
Average photon energy;PV materials;Spectral measurements;Power conversion performance
摘要：
Solar spectral irradiance distributions have a great impact on the photoelectric conversion performance of photovoltaic materials. By average photon energy, this paper assessed the practical conversion performance of ten types of photovoltaic materials based on the spectral measurements of Beijing and Changsha, China. Photon energy utilization efficiency was proposed to assess the practical conversion performance of photovoltaic materials at the same aperture area. Monocrystalline silicon had the best energy utilization efficiency when the spectrum is the red-rich or close to the reference spectrum. However, gallium arsenide would outperform it if the average photon energy exceeded 1.95 eV. Mismatch factor was used at the same rated output power of photovoltaic materials. It is found that the mismatch factor of perovskite with a 1.22 eV bandgap energy ranks the first place when the spectrum is the red-rich or close to the reference spectrum. However, the perovskite with a 1.83 eV bandgap energy has the optimal conversion performance at the average photon energy over 1.83 eV. Moreover, an ideal photovoltaic material with advanced properties was proposed for optimal performance with the regional spectra, which might provide useful instruction for photovoltaic industries to produce the most suitable photovoltaic material considering the annual regional spectrum.
作者机构：
[Qing, Mengxia; Zheng, Yang; Liu, Liang; Huang, Sibiao; Zeng, Hongliang; Tian, Hong] School of Energy and Power Engineering, Changsha University of Science and Technology, Changsha;410114, China;Hunan Zhongding Thermal Technology Co., Ltd, Yueyang;414000, China;[Xiang, Jun] State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan
通讯机构：
[Liang Liu; Jun Xiang] S;School of Energy and Power Engineering, Changsha University of Science and Technology, Changsha 410114, China<&wdkj&>State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
关键词：
Density functional theory;Food waste;NOx precursor;Pyrolysis
