Review
Energy & Fuels
Shahryar Zare, A. R. Tavakolpour-saleh, A. Aghahosseini, M. H. Sangdani, Reza Mirshekari
Summary: This paper discusses the application of soft computing methods in the optimization and design of Stirling engines, including genetic algorithms, particle swarm optimization, fuzzy logic, and artificial neural networks. These soft computing methods can effectively address the main concerns of researchers, and optimizing parameters can improve the performance of Stirling engines.
Article
Green & Sustainable Science & Technology
Moh'd Al-Nimr, Saud A. Khashan, Hashem Al-Oqla
Summary: This paper presents three novel techniques to enhance Stirling engines (SE). The use of Phase-Change Material (PCM) regenerators instead of conventional regenerators improves the performance of both the regenerator and the engine. Replacing the plate receiver of a Solar-Dish Stirling engine (SDSE) with a glass receiver increases direct radiation absorption and reduces energy losses. Coupling an SDSE system with a PCM Thermal Storage Reservoir (PCMTSR) allows for the storage and extraction of rejected heat energy during the day and night, utilizing either ambient air or geothermal water for night-time engine cooling. Theoretical models evaluate the impact of these modifications on SE performance.
Article
Multidisciplinary Sciences
Raphael Paul, Karl Heinz Hoffmann
Summary: This paper introduces a method to optimize the piston paths of non-equilibrium Stirling engines using an indirect iterative gradient algorithm for different objectives such as power and efficiency. By exploiting limit cycles to solve the optimal control problem, significant gains in power and efficiency are achieved compared to harmonic piston paths. At the maximum power point, the power-optimal control results in a relative power gain of approximately 28%, while the efficiency-optimal control at the maximum efficiency point leads to a relative efficiency gain of around 10%.
Editorial Material
Chemistry, Physical
Alberto Boretti
Summary: Current alpha-Stirling engine designs have not reached Carnot cycle efficiency, but by using hydrogen as working fluid and adopting specific structures, higher energy conversion efficiencies can be achieved. Compared to current air microturbines, the efficiency is significantly higher.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Review
Energy & Fuels
Jiale Huang, Rui Yang, Yupeng Yang, Qiang Zhou, Ercang Luo
Summary: Thermoacoustic heat engines convert thermal energy into acoustic power or vice versa, offering high reliability and low environmental impact. Unconventional working substances, such as liquid, transcritical fluid, two-phase fluid, fluid with wall mass transfer, and solid, have been explored in recent decades to improve thermoacoustic conversion. This review critically examines the progress, mechanisms, existing prototypes, operation characteristics, and potential applications of generalized thermoacoustic engines and refrigerators using unconventional working substances. These systems demonstrate unique advantages, such as better performance at low temperature difference operation, larger pressure amplitudes, or more compact heat exchangers, making them promising for low-grade heat recovery, household air conditioning, etc.
Article
Multidisciplinary Sciences
Changjun Fan, Mutian Shen, Zohar Nussinov, Zhong Liu, Yizhou Sun, Yang-Yu Liu
Summary: Finding the ground states of spin glasses is challenging, and the authors propose a deep reinforcement learning framework that can be trained on small-scale instances and applied to larger ones. This framework displays better scalability and can help solve hard combinatorial optimization problems.
NATURE COMMUNICATIONS
(2023)
Article
Computer Science, Interdisciplinary Applications
Chen-Xu Liu, Gui-Lan Yu
Summary: This study introduces a new deep learning model for the design of periodic wave barriers, which is proven to be effective in quickly generating designs that meet specific targets. The deep learning model makes the design of periodic wave barriers smarter and more efficient.
COMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING
(2022)
Article
Computer Science, Artificial Intelligence
Raphael Pestourie, Youssef Mroueh, Chris Rackauckas, Payel Das, Steven G. Johnson
Summary: This study introduces a 'physics-enhanced deep-surrogate' (PEDS) approach for developing fast surrogate models for complex physical systems described by partial differential equations (PDEs). The PEDS approach combines a low-fidelity physics simulator and a neural network generator, trained end-to-end to match the output of a high-fidelity numerical solver. Experiments demonstrate that the PEDS surrogate is more accurate than a limited-data ensemble of feedforward neural networks and reduces the training data requirement.
NATURE MACHINE INTELLIGENCE
(2023)
Article
Multidisciplinary Sciences
Katharina Dobs, Joanne Yuan, Julio Martinez, Nancy Kanwisher
Summary: Using deep convolutional neural networks (CNNs), this study reveals that the behavioral signatures of human face perception can be explained as the result of optimization for the task of face recognition, suggesting that the nature of the computations underlying this task may not be so special after all.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Thermodynamics
A. R. Tavakolpour-Saleh, Shahryar Zare
Summary: This paper presents a novel lumped mechanical model incorporating modern control theory to investigate performance and startup condition of thermo-acoustic Stirling engines (TASEs). The study reveals that TASEs can be considered as physical regulators from the viewpoint of modern control theory. Design parameters and quality index are analyzed to evaluate resonance phenomenon in the TASEs, and the proposed mathematical model incorporating the control-based design technique is validated using practical data of three prototype engines.
Article
Thermodynamics
H. Yousefzadeh, A. R. Tavakolpour-Saleh
Summary: This paper presents a novel method to calculate and predict the damping coefficient and overall performance of a kinematic Stirling engine. Through a comprehensive model and experimental validation, the effectiveness of the model was confirmed.
Article
Mathematics, Interdisciplinary Applications
Shahryar Zare, A. R. Tavakolpour-Saleh, T. Binazadeh
Summary: This paper presents an analytical and parametrical scheme based on practical stability and dynamic error to evaluate the existence of a stable limit cycle in free piston Stirling engines (FPSEs). Nine parametric conditions are provided to satisfy the sufficient condition for a stable oscillation of the FPSE. Additionally, a design criterion for evaluating design accuracy is proposed. The method is evaluated through two experimental case studies and shown to accurately predict the sufficient condition of the FPSEs.
CHAOS SOLITONS & FRACTALS
(2023)
Article
Thermodynamics
Hang-Suin Yang, Hao-Qiang Zhu, Xian-Zhong Xiao
Summary: This study investigates the dynamic characteristics and performance of beta-type Stirling engines (BTSEs) with five driving mechanisms. A thermodynamic model is used to predict the variations in the thermal properties of the working fluid, and friction losses are considered in the dynamic models. The results show that the trajectories of the piston and displacer significantly affect the performance of BTSEs. Among the five mechanisms, BTSEs with the bell crank mechanism achieve the highest shaft power (1533 W) at 550 rpm, with a mechanical efficiency of 80.5%.
Article
Multidisciplinary Sciences
Zhengcai Li, Xinmin Hu, Chun Chen, Chenyang Liu, Yalu Han, Yuanfeng Yu, Lizhi Du
Summary: This paper investigates the optimization algorithms based on machine learning for settlement prediction. By comparing the performance of different algorithms, the study finds that Sparrow Search Algorithm (SSA) significantly improves the optimization effect of the gradient descent model and enhances its stability to a certain degree.
SCIENTIFIC REPORTS
(2022)
Article
Computer Science, Artificial Intelligence
Adedamola Wuraola, Nitish Patel, Sing Kiong Nguang
Summary: This study introduces a family of square-based activation functions for embedded devices with high computational efficiency and resource utilization. The family demonstrates universal ability across various neural network architectures, improving performance and speed-up in applications such as support vector machines, recurrent neural networks, etc.
Article
Energy & Fuels
Chin-Hsiang Cheng, Duc-Thuan Phung
Summary: The study presents a three-dimensional CFD model for simulating a compact 100-W beta-type Stirling engine, and explores the influence of various parameters on engine performance in terms of power and thermal efficiency. Results show that heating temperature, cooling temperature, and piston length have significant effects on both power output and thermal efficiency of the engine.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2021)
Article
Thermodynamics
Chin-Hsiang Cheng, Jian-Hua Feng, Jhen-Syuan Huang
Summary: This paper focuses on the development of a thermodynamic model and a heat-driven Vuilleumier refrigerator, analyzing the thermodynamic properties and performance. A prototype Vuilleumier refrigerator with a crank drive mechanism was built and its performance measured. The effects of various parameters on the cold head temperature were evaluated and numerical results were validated against experimental data.
INTERNATIONAL JOURNAL OF REFRIGERATION
(2021)
Article
Energy & Fuels
Chin-Hsiang Cheng, Jhen-Syuan Huang
Summary: This study aimed to develop a tri-generation system that converts thermal energy into mechanical power, cooling, and heating. By combining a Stirling cooler and a Stirling engine, the system achieved high overall efficiency of approximately 91%, as demonstrated by experiments closely aligning with numerical predictions.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2021)
Article
Green & Sustainable Science & Technology
Chin-Hsiang Cheng, Surender Dhanasekaran
Summary: This study focuses on the development of a Permanent Magnet Linear Alternator (PMLA) and parametrically analyzes it to predict its limitations and performance. By varying operable conditions and material choice, the machine is analyzed and tested for its extreme limitations. The introduction of spacing between slots also increases the power density.
Article
Green & Sustainable Science & Technology
Chin-Hsiang Cheng, Yi-Han Tan, Tzu-Sung Liu
Summary: This research developed a numerical model for a double-acting four-cylinder alpha-type Stirling engine, combining thermodynamic and dynamic models to study its performance. Experimental results showed that under specific temperature, pressure, and torque conditions, the engine can achieve a certain shaft power. The model can also validate and further simulate the thermal properties and transient behavior of the engine.
Article
Thermodynamics
Chin-Hsiang Cheng, Hang-Suin Yang, Yi-Han Tan
Summary: This paper proposes an energy method to solve the relationship between the crank angle of the main shaft and the work generated by the working fluid in a double-acting Stirling engine with a wobble yoke mechanism. The study also employs a modified non-ideal adiabatic model to predict the transient variation in thermal properties of the working fluid. The simulation results demonstrate the potential of the proposed engine in terms of maximum shaft power and performance prediction.
Article
Thermodynamics
Hang-Suin Yang, Chin-Hsiang Cheng, Muhammad Aon Ali
Summary: This study proposes a theoretical model for analyzing the performance and operating modes of a thermal-lag Stirling engine. The model is solved by the method of multiple scales, and it predicts the performance, operating regions, and transitions between different modes. The performance of the engine under stable operating state and the dependence of the indicated power on engine speed are evaluated. An optimal loading and a minimum operating speed are also predicted.
APPLIED THERMAL ENGINEERING
(2022)
Article
Energy & Fuels
Chin-Hsiang Cheng, Yu-Ting Lin
Summary: This study aimed to develop an algorithm for the computational optimization of free-piston Stirling engines. The algorithm includes an optimization method and compatible strategies, which can handle multiple-parameter optimization and provide faster convergence.
Article
Engineering, Manufacturing
Chin-Hsiang Cheng, Cherng-Chyi Loh, Yi-Jie Zhang
Summary: This study uses a composite material with copper powder added in Polylactide (PLA) to manufacture metallic parts via 3D printing, and sintering process is applied for PLA removal and mechanical strengthening. Numerical simulation is conducted to investigate the heat transfer characteristics of the system during heating process.
PROGRESS IN ADDITIVE MANUFACTURING
(2022)
Article
Chemistry, Physical
Chin-Hsiang Cheng, Yi-Shen Chen, Hsin-Yu Tsai, Yu-Ling Liang, David T. W. Lin, Yitung Chen
Summary: The present study aims to develop and test a cost-effective and efficient printing method for fabricating flexible metamaterial film with high electromagnetic wave absorptivity. Numerical and experimental results show that the flexible metamaterial film fabricated using a silver nanoparticles ink jet printer has a high absorptivity.
Article
Energy & Fuels
Chin-Hsiang Cheng, Duc-Thuan Phung
Summary: Thermal-lag engines are external combustion engines with a single moving piston, resulting in lower manufacturing and maintenance costs. This study focuses on the performance of thermal-lag engines by developing a three-dimensional computational fluid dynamics model and validating it with experimental data. The study finds that the CFD model's predictions align well with the experimental data and highlights the significant impact of engine speed and temperature on engine power.
Article
Energy & Fuels
Chin-Hsiang Cheng, Surender Dhanasekaran
Summary: This research focuses on reducing the cogging force acting on the translator of a slot-spaced Permanent Magnet Linear Alternator (PMLA) by making geometrical changes to the machine structure. The aim is to align the cogging force profile with the displacement profile of the translator to minimize vibrations and prevent damage to the piston of the Free Piston Stirling Engine (FPSE). The outcome of this work is achieving a balance between reduced voltage and cogging force through minor geometrical changes and a sinusoidal cogging force profile.
Article
Energy & Fuels
Chin-Hsiang Cheng, Shang-Ting Huang
Summary: This study aims to model a hybrid power system that can continuously generate power by switching between solar radiation and combustion energy from synthesis gases. The system includes a hybrid energy receiver, solar dish, Stirling generator, fluidized-bed gasifier, boiler, and water tank. The modeling results indicate that switching can result in a continuous power output ranging from 600 to 1200 W.
ENERGY SCIENCE & ENGINEERING
(2023)
Article
Thermodynamics
Jhen-Syuan Huang, Chin-Hsiang Cheng
Summary: This paper presents a theoretical model for analyzing the performance of a rotary-integral Stirling cryocooler. Transient variations of thermodynamic properties are used to predict cooling temperature and capacity. A precise evaluation method for the regenerator is introduced, and temperature and pressure dependent thermophysical properties are considered. An experimental prototype is manufactured and numerical results from the model are validated. The results show good agreement between the predicted and measured values, indicating the effectiveness of the proposed model. Parametric studies are also conducted to explore performance enhancements.
THERMAL SCIENCE AND ENGINEERING PROGRESS
(2023)
Article
Energy & Fuels
Chin-Hsiang Cheng, Surender Dhanasekaran
Summary: This research focuses on the design and development of a tubular slot-spaced Permanent Magnet Linear Alternator coupled with Free-Piston Stirling Engines. By studying parameters, the power density of the machine has been increased, and the performance variation of the machine under different conditions has been studied.
