Review
Construction & Building Technology
Ziyan Fu, Jorge Corker, Theodosios Papathanasiou, Yuxuan Wang, Yonghui Zhou, Omar Abo Madyan, Feiyu Liao, Mizi Fan
Summary: This review examines the thermal conductivity and related models of aerogels and their composites, investigates the impact of the nanoporous structure and nano-skeleton on heat transfer, evaluates the progress and remaining challenges in the field, and proposes directions for further research and development.
JOURNAL OF BUILDING ENGINEERING
(2022)
Article
Chemistry, Multidisciplinary
Yafen Han, Shuai Li, Haidong Liu, Yucong Li
Summary: In order to study the heat conduction of nanoporous aerogel, a gas-solid heat conduction model was established based on the microstructure of aerogel. The model was divided into two subdomains and simulated using the lattice Boltzmann method. It was found that the temperature distribution of the solid phase became more uniform with increasing scale, and the temperature jump on the gas-solid interface decreased with increasing gas-phase scale. Additionally, the thermal conductivity of gas-solid coupling varied with the scale of the gas phase or solid phase, showing a scale effect.
Article
Thermodynamics
Tianmi Wang, Qiaoling Si, Yang Hu, Guihua Tang, Kian Jon Chua
Summary: This study proposes a novel aerogel composited with plasmonic nanoparticles and opacifiers for high-efficiency photothermal conversion. The radiative characteristics of the aerogel composite were numerically investigated and it was found that the opacifiers promote extinction characteristics in the infrared range while the plasmonic nanoparticles enhance absorption efficiency in the solar spectrum. Silica aerogels doped with silver nanoparticles and indium tin oxide particles were prepared and tested, showing a high absorption efficiency in the solar spectrum and reduced heat loss in the infrared range.
Article
Nanoscience & Nanotechnology
Shunyao Zhang, Lukai Wang, Junzong Feng, Yonggang Jiang, Liangjun Li, Jian Feng
Summary: A template orientation strategy was proposed for fabricating nanoporous aerogel-like silica monoliths (ASMs) using low-cost, rapid ambient drying technology. The silica slurry composed of commercial fumed silica, hydrolyzed methyltrimethoxysilane (MTMS), and water solvent solidified through a controlled polycondensation reaction catalyzed by ammonia. The resulting ASMs exhibited typical nanopore features with high specific surface area and pore diameter distribution concentrated at around 40 nm. This simple and low-cost preparation strategy could promote the large-scale applications and industrial production of nanoporous silica for thermal insulation materials.
ACS APPLIED NANO MATERIALS
(2023)
Article
Thermodynamics
He Liu, Jia'ao Liu, You Tian, Xuehong Wu, Zengyao Li
Summary: Pure silica aerogel has high transmittance at high temperature, so ceramic fibers with a diameter comparable to the wavelength of incident thermal radiation are introduced to reduce the radiative thermal conductivity. Aligning the fibers perpendicular to the incident radiation is the most effective way to minimize the radiative thermal conductivity, and the optimal fiber diameter decreases with increasing temperature. There exists an optimal mass fraction of doped fibers to achieve the minimized thermal conductivity due to the trade-off relationship between the conductive and radiative thermal conductivities.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Thermodynamics
He Liu, Jia'ao Liu, You Tian, Xuehong Wu, Zengyao Li
Summary: Silica aerogel is a promising material for thermal insulation applications due to its low thermal conductivity and density. To improve its performance, ceramic fibers are introduced into the pure silica aerogel. This study developed a theoretical model to investigate the thermal conductivity of fiber-reinforced aerogel composites at high temperature, considering the inclination angle, diameter, and mass fraction of the doped fibers.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Chemistry, Multidisciplinary
Bingjie Ma, Yingying Cheng, Peiying Hu, Dan Fang, Jin Wang
Summary: The passive radiative cooling behavior of traditional silica aerogels prepared from methyltrimethoxysilane (MTMS) and dimethyldimethoxysilane (DMDMS) was investigated in outdoor environments. The study found that silica aerogels showed excellent thermal insulation performance in room environments, but could achieve sub-ambient cooling of 12 degrees Celsius on a clear night and up to 7.5 degrees Celsius in the daytime.
Article
Materials Science, Ceramics
Haoran Du, Shijie Wang, Yiqiang Xing, Xiang Li, Mengbo Pan, Wenhao Qi, Chengliang Ma
Summary: Zirconia fiber enhances the strength and reduces the radiative heat transfer of the fumed silica-based thermal insulation material, resulting in lower density, high porosity, and lower thermal conductivity at high temperatures.
CERAMICS INTERNATIONAL
(2022)
Article
Polymer Science
Fengfei Lou, Sujun Dong, Yinwei Ma, Bin Qi, Keyong Zhu
Summary: This study investigated the thermal transport mechanism in aerogels of metal thermal protection system (MTPS) using CFD numerical simulation, particularly focusing on the impact of emissivity on thermal insulation performance. The results indicated that reducing emissivity can significantly enhance thermal insulation performance, especially for materials with small extinction coefficients at high temperatures.
Article
Polymer Science
Conal Thie, Sean Quallen, Ahmed Ibrahim, Tao Xing, Brian Johnson
Summary: Energy consumption in buildings is expected to increase, and one potential way to reduce it is by using silica aerogels as a thermal insulator. To study their benefits, simulations were performed on a model of a residential house using ANSYS FLUENT 2019 R2. The results showed that using aerogels in walls and windows could lead to significant energy savings.
Article
Chemistry, Multidisciplinary
Sichao Li, Robert E. Simpson, Sunmi Shin
Summary: Researchers used a new measurement platform to quantify thermal signals in a Ge2Sb2Te5/SiO2 nanoribbon structure. They were able to separate and quantify the radiated and conducted heat transfer mechanisms. The thermal emission from the Ge2Sb2Te5/SiO2 nanoribbons was enhanced by 3.5x compared to that of a bare SiO2 nanoribbon. This enhancement was directly due to polaritonic heat transfer enabled by the large and lossless dielectric permittivity of Ge2Sb2Te5 at mid-IR frequencies.
Article
Thermodynamics
Ke Yang, Maoquan Huang, Rifeng Zhou, Qingli Cheng, Jin Huan Pu, G. H. Tang, Mu Du
Summary: This study addresses the issue of compromised high-temperature performance of silica aerogel by investigating the influence of opacifier shape. Non-spherical carbon black opacifiers and ellipsoidal Carbon@SiC core-shell opacifiers are introduced to enhance the insulation properties of aerogels. The findings provide a pragmatic approach to fabricating aerogels with enhanced insulation properties at high temperatures.
THERMAL SCIENCE AND ENGINEERING PROGRESS
(2023)
Article
Thermodynamics
Rajesh Mishra, B. K. Behera, Miroslav Muller, Michal Petru
Summary: This study examined the thermal insulation properties of nonwoven samples embedded with silica aerogel using finite element simulations and experimental measurements. The results showed a high correlation between the FEM based simulations and experimental measurements, providing theoretical support for the use of aerogel blankets in house buildings at sub-zero temperatures.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2021)
Article
Engineering, Environmental
Zuzanna Kantor, Tingting Wu, Zhihui Zeng, Sabyasachi Gaan, Sandro Lehner, Milijana Jovic, Anne Bonnin, Zhengyuan Pan, Zahra Mazrouei-Sebdani, Dorina M. Opris, Matthias M. Koebel, Wim J. Malfait, Shanyu Zhao
Summary: Polymer aerogels are a promising alternative to brittle silica aerogels, but they lack high-temperature stability. Researchers have developed a new type of aerogel composite with unique structure and excellent properties, which could be used in applications requiring high mechanical strength, low thermal conductivity, and low dielectric constant.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Materials Science, Multidisciplinary
Fuwei Yang, Bai Song
Summary: Active control of heat flow is important in thermal management and energy conversion. The study focuses on thermal radiation between twisted bilayer graphene (TBLG), showing that near-field heat flow can vary significantly with twist angle, chemical potential, and temperature. The findings suggest potential for manipulating radiative heat flow through surface plasmons in TBLG.
Article
Thermodynamics
Hai Zhao, Puzhen Gao, Xiaochang Li, Ruifeng Tian, Hongyang Wei, Sichao Tan
Summary: This study numerically investigates the interaction between flow-induced vibration and forced convection heat transfer in a tube bundle. The results show that the impact of flow-induced vibration on heat transfer varies in different flow velocity regions.
APPLIED THERMAL ENGINEERING
(2024)
Article
Thermodynamics
Rohit Chintala, Jon Winkler, Sugirdhalakshmi Ramaraj, Xin Jin
Summary: The current state of fault detection and diagnosis for residential air-conditioning systems is expensive and not suitable for widespread implementation. This paper proposes a cost-effective solution by introducing an automated fault detection algorithm as a screening step before more expensive tests can be conducted. The algorithm uses home thermostats and local weather information to identify thermodynamic parameters and detect high-impact air-conditioning faults.
APPLIED THERMAL ENGINEERING
(2024)
Article
Thermodynamics
A. Azimi, N. Basiri, M. Eslami
Summary: This paper presents a novel optimization algorithm for improving the water-film cooling system of photovoltaic panels, resulting in a significant increase in net energy generation.
APPLIED THERMAL ENGINEERING
(2024)
Article
Thermodynamics
Duc-Thuan Phung, Chin-Hsiang Cheng
Summary: In this study, a novel CFDMD model is used to analyze and investigate the behavior of thermal-lag engines (TLE). The study shows that the CFDMD model effectively captures the thermodynamic behavior of the working gas and the dynamic behavior of the engine mechanism. Additionally, the study explores the temporal evolution of engine speed and the influence of various parameters on shaft power and brake thermal efficiency. The research also reveals the existence of a thermal-lag phenomenon in TLE.
APPLIED THERMAL ENGINEERING
(2024)
Article
Thermodynamics
Haiying Yang, Yinjie Shen, Lin Li, Yichen Pan, Ping Yang
Summary: The purpose of this article is to find a measure to improve the interfacial thermal transfer of graphene/silicon heterojunction. Through molecular dynamics simulation, it is found that surface modification can significantly reduce the thermal resistance, thereby improving the thermal conductivity of the graphene/silicon interface.
APPLIED THERMAL ENGINEERING
(2024)
Article
Thermodynamics
Qiong Wu, Yancheng Wang, Haonan Zhou, Xingye Qiu, Deqing Mei
Summary: This article introduces a visible methanol steam reforming microreactor, which uses an optical crystal as an observation window and measures the reaction temperature in real-time using infrared thermography. The results show that under lower oxygen to carbon ratio conditions, the microreactor has a higher heating rate and a stable gradient in temperature distribution.
APPLIED THERMAL ENGINEERING
(2024)
Review
Thermodynamics
Giulia Manco, Umberto Tesio, Elisa Guelpa, Vittorio Verda
Summary: In the past decade, there has been a growing interest in studying energy systems for the combined management of power vectors. Most of the published works focus on finding the optimal design and operations of Multi Energy Systems (MES). However, for newcomers to this field, understanding how to achieve the desired optimization details while controlling computational expenses can be challenging and time-consuming. This paper presents a novel approach to analyzing the existing literature on MES, with the aim of guiding practical development of MES optimization. Through the discussion of six case studies, the authors provide a mathematical formulation as a reference for building the model and emphasize the impact of different aspects on the problem nature and solver selection. In addition, the paper also discusses the different approaches used in the literature for incorporating thermal networks and storage in the optimization of multi-energy systems.
APPLIED THERMAL ENGINEERING
(2024)
Article
Thermodynamics
Xuepeng Yuan, Caiman Yan, Yunxian Huang, Yong Tang, Shiwei Zhang, Gong Chen
Summary: In this study, a multi-scale microgroove wick (MSMGW) was developed by laser irradiation, which demonstrated superior capillary performance. The surface morphology and performance of the wick were affected by laser scan pitch, laser power, repetition frequency, and scanning speed. The MSMGW showed optimal capillary performance in alumina material and DI water as the working fluid.
APPLIED THERMAL ENGINEERING
(2024)
Article
Thermodynamics
Maofei Mei, Feng Hu, Chong Han
Summary: This paper proposes an effective local search method based on detection of droplet boundaries for understanding the dynamic process of droplet growth during dropwise condensation. The method is validated by comparing with experimental data. The present simulation provides an effective approach to more accurately predict the nucleation site density in future studies.
APPLIED THERMAL ENGINEERING
(2024)
Article
Thermodynamics
Rahul Kumar Sharma, Ashish Kumar, Dibakar Rakshit
Summary: The study explores the use of phase change materials (PCM) as a retrofit with Heating Ventilation and Air-conditioning systems (HVAC) to reduce energy consumption and improve air quality. By incorporating PCM with specific thickness and fin configurations, significant energy savings can be achieved in comparison to standard HVAC systems utilizing R134a. This research provides policymakers with energy-efficient and sustainable solutions for HVAC systems to combat climate change.
APPLIED THERMAL ENGINEERING
(2024)
Article
Thermodynamics
Zhenhua Ren, Xiangjin Meng, Xingang Qi, Hui Jin, Yunan Chen, Bin Chen, Liejin Guo
Summary: This paper investigates the heat transfer mechanism and factors influencing thermal radiation in the process of supercritical water gasification (SCWG) of coal, and proposes a comprehensive numerical model to simulate the process. Experimental validation results show that thermal radiation accounts for a significant proportion of the total heat exchange in the reactor and a large amount of radiant energy exists in the important spectral range of supercritical water. Enhancing radiative heat transfer can effectively increase the temperature of the reaction medium and the gasification rate.
APPLIED THERMAL ENGINEERING
(2024)
Article
Thermodynamics
Mauro Abela, Mauro Mameli, Sauro Filippeschi, Brent S. Taft
Summary: Pulsating Heat Pipes (PHP) are passive two-phase heat transfer devices with a simple structure and high heat transfer capabilities. The actual unpredictability of their dynamic behavior during startup and thermal crisis hinders their large-scale application. An experimental apparatus is designed to investigate these phenomena systematically. The results show that increasing the number of evaporator sections and condenser temperature improves the performance of PHP. The condenser temperature also affects the initial liquid phase distribution and startup time.
APPLIED THERMAL ENGINEERING
(2024)
Article
Thermodynamics
Ke Gan, Ruilian Li, Yi Zheng, Hui Xu, Ying Gao, Jiajie Qian, Ziming Wei, Bin Kong, Hong Zhang
Summary: A 3-dimensional enhanced heat pipe radiator has been developed to improve heat dissipation and temperature uniformity in cooling high-power electronic components. Experimental results show that the radiator has superior heat transfer performance compared to a conventional aluminum fin radiator under different heating powers and wind speed conditions.
APPLIED THERMAL ENGINEERING
(2024)
Article
Thermodynamics
Xinyi Zhang, Shuzhong Wang, Daihui Jiang, Zhiqiang Wu
Summary: This study focuses on recovering waste heat from blast furnace slag using dry centrifugal pelletizing technology. A comprehensive two-dimensional model was developed to analyze heat transfer dynamics and investigate factors influencing heat exchange efficiency. The findings have important implications for optimizing waste heat recovery and ensuring safe operations.
APPLIED THERMAL ENGINEERING
(2024)
Article
Thermodynamics
Xincheng Wu, An Zou, Qiang Zhang, Zhaoguang Wang
Summary: The boosting heat generation rate of high-performance processors is challenging traditional cooling techniques. This study proposes a combined design of active jet intermittency and passive surface modification to enhance heat transfer.
APPLIED THERMAL ENGINEERING
(2024)