Article
Thermodynamics
Luan Nguyen Thanh
Summary: This study investigates the influence of baffle configuration and flow parameters on heat transfer and entropy generation in a baffled channel. Numerical simulation and optimization analysis were conducted, revealing that Reynolds number has the highest impact on Nusselt number, thermo-hydraulic performance, and dimensionless entropy generation.
CASE STUDIES IN THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Antash Najib, Angelo Zarrella, Vinod Narayanan
Summary: This paper introduces a new approach to calculate the transfer functions for large diameter, shallow bore helical Ground Heat Exchangers using mean fluid temperature. The proposed method shows promising results in estimating the performance of Helical GHEs by analyzing the mean fluid temperature for different mass flowrates. The study provides mathematical formulations and a simplified resistance-based model for calculating the g-functions, demonstrating the effectiveness of the approach in predicting the thermal performance of the systems.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Junhao Shen, Chaohui Zhou, Yongqiang Luo, Zhiyong Tian, Shicong Zhang, Jianhua Fan, Zhang Ling
Summary: This study introduces an analytical model based on the Segmented Finite Line Source (SFLS) method to analyze the heat transfer process of a U-type deep borehole heat exchanger (UDBHE). The model is validated by comparing it with experimental data. Results show that the heat extraction capacity of the UDBHE is influenced by design and operation parameters such as the thermal conductivity of the backfill material, pipe diameter, and flow rate.
Review
Environmental Sciences
Syed Noman, Harinarayana Tirumalachetty, Muthu Manokar Athikesavan
Summary: This paper provides an extensive review on geothermal heating and cooling systems, focusing on Earth-Air Heat Exchangers (EAHE) and Ground Source Heat Pump (GSHP) systems. The study identifies that the thermal conductivity of soil and the water content in the ground have significant effects on system performance.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2022)
Article
Thermodynamics
Siyuan Wu, Rijing Zhao, Xinghua Wei, Zhiheng Ma, Dong Huang, Yongfeng Zhao
Summary: This article uses CFD to analyze the air-side thermal-hydraulic performance of vertical-fin microchannel heat exchangers (VMHXs) under dry conditions. The model is verified with experimental results, showing an error of less than 20%. The effects of fin pitch, fin length, tube pitch, and fin thickness are investigated, and parameter optimization is conducted using the Taguchi method. The best performance is obtained with a combination of 1.8 mm fin pitch, 25.6 mm fin length, 12.0 mm flat tube pitch, and 0.12 mm fin thickness, when considering the comprehensive index performance evaluation criteria (PEC).
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Hao-fei Cai, Yu-yan Jiang, Tao Wang, Shi-qiang Liang, Cong Guo, Yu-ming Zhu
Summary: This paper presents a new simulation method with lower computation consumption for microtube heat exchangers used for supercritical CO2 cooling. By analyzing heat transfer characteristics and relationships, the study focuses on optimizing baffles arrangement to reduce pressure loss and enhance heat transfer performance.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Emre Turgut, Ugurcan Yardimci
Summary: This study analyzes the effects of semicircular striped turbulators inserted into the inner tube of a coaxial heat exchanger on heat transfer, friction factor, and thermal performance factor. The results show that this design significantly improves heat transfer and reduces the friction factor, resulting in improved thermal performance. Taguchi Experimental Design, Analysis of Variance, and Grey Relational Analysis are applied to determine optimal parameter levels and evaluate the effects of different parameters. The Reynolds number is found to have the most significant impact on heat transfer, while the pitch has the weakest effect. The arrangement style of the turbulators has the strongest effect on the friction factor. Overall, this study provides valuable insights for optimizing heat transfer performance in coaxial heat exchangers with turbulators.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2022)
Article
Energy & Fuels
Hongtao Li, Shuai Zhang, Yunguang Ji, Mingxu Sun, Xudong Li, Yonggang Sheng
Summary: This study investigates the variation of the comprehensive heat transfer performance index for heat exchangers at different Reynolds numbers through numerical simulation, showing that extending the inlet and outlet of the external passage can enhance heat transfer performance, with limited impact from extending the outlet.
Review
Construction & Building Technology
Ramy H. Mohammed, Mohamed El-Morsi, Omar Abdelaziz
Summary: Indirect evaporative cooling (IEC) is an eco-friendly technology that can significantly reduce energy consumption. However, its application is limited in humid environments and arid environments with limited water resources. Past research has mainly focused on IEC device performance and configuration, while current studies are addressing issues such as device size and nonuniform wettability of the wet channel surface. With further research and development, IEC technology is expected to play a greater role in the air conditioning market in the next few decades, aiming to reduce energy consumption and carbon footprint in the building sector.
JOURNAL OF BUILDING ENGINEERING
(2022)
Article
Green & Sustainable Science & Technology
Sajjan Pokhrel, Agus P. Sasmito, Atsushi Sainoki, Toshiyuki Tosha, Tatsuya Tanaka, Chiaki Nagai, Seyed Ali Ghoreishi-Madiseh
Summary: This study investigates a 500 m deep coaxial borehole heat exchanger system for geothermal power generation through experimental and computational analyses. The numerical model accurately predicts the underground temperature distribution and the output power of the geothermal system. A parametric study shows that the total thermal energy generated by the geothermal system can reach up to 194 MWh, and after extraction is terminated, the ground temperature can recover to around 86% of the initial temperature within 456 hours.
Article
Energy & Fuels
Yuting Zhuo, Siwoo Jung, Yansong Shen
Summary: Efficient heat transfer is crucial for hydrogen desorption in metal hydride-based hydrogen storage systems. A 3D transient-state CFD model was developed to describe heat/mass transfer phenomena in a metal hydride-based hydrogen storage tank, validated with temperature evolution data. New tank designs with heating tubes, copper fins, and aluminum foam were proposed to enhance heat transfer efficiency and hydrogen desorption. Simulation results showed significantly improved desorption performance in terms of heating rate and hydrogen desorption rate with the new designs.
Article
Thermodynamics
Kim Leong Liaw, Jundika C. Kurnia, Agus P. Sasmito
Summary: This study investigates the convective heat transfer performance of Newtonian fluid in a helical twisted multilobe tube using computational fluid dynamics (CFD) simulations. The results show that the combination of number of lobes and tube twisting has a significant effect on the heat transfer coefficient, while increasing the number of lobes alone has a minimal impact. The helical coiled tube outperforms the straight tube within a certain range of Reynolds numbers, while twisting is recommended primarily for straight tubes.
CASE STUDIES IN THERMAL ENGINEERING
(2022)
Article
Green & Sustainable Science & Technology
Faraz Afshari, Emre Mandev, Fatih Yildiz, Fatih Yildiz
Summary: This study analyzes the influence of the base thickness of the external heat exchanger on the cooling performance of air-to-air thermoelectric cooling systems, and evaluates it through experimental and numerical methods. The experimental results show that reducing the thickness from 4.5mm to 1.5mm led to a 14% difference in temperature in the cooling chamber under different working conditions. The numerical simulation reveals the airflow structure and temperature distribution inside and outside the refrigerator.
SUSTAINABLE ENERGY TECHNOLOGIES AND ASSESSMENTS
(2022)
Article
Thermodynamics
Jinhui Liu, Mengmeng Ai
Summary: This paper focuses on the improvement of heat transfer efficiency of air cooled high voltage motor heat exchanger. A mathematical and physical model of the heat exchanger is established based on hydrodynamics and numerical heat transfer theory. The model is validated with experimental data and optimized to enhance the heat transfer capacity of the heat exchanger.
CASE STUDIES IN THERMAL ENGINEERING
(2022)
Article
Green & Sustainable Science & Technology
Michal Chwieduk
Summary: This paper presents a new numerical model of the vertical U-tube ground heat exchanger, describing different approaches for modeling GHE and emphasizing a new thermal resistance model. The simulation results show a 3% difference compared to in-situ data.
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)