Constructal thermodynamic optimization for dual-pressure organic Rankine cycle in waste heat utilization system
TL;DR: In this article, a constructal thermodynamic optimization (CTO) based on a combination of constructal theory and finite-time thermodynamics is proposed for the dual-pressure organic Rankine cycle (DPORC) to solve energy problems.
About: This article is published in Energy Conversion and Management.The article was published on 2021-01-01. It has received 62 citations till now. The article focuses on the topics: Organic Rankine cycle & Constructal law.
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TL;DR: In this paper, an improved irreversible closed modified simple Brayton cycle model with one isothermal heating process is established by using finite time thermodynamics, and the impacts of the irreversible losses on the optimization results are analyzed.
Abstract: An improved irreversible closed modified simple Brayton cycle model with one isothermal heating process is established in this paper by using finite time thermodynamics. The heat reservoirs are variable-temperature ones. The irreversible losses in the compressor, turbine, and heat exchangers are considered. Firstly, the cycle performance is optimized by taking four performance indicators, including the dimensionless power output, thermal efficiency, dimensionless power density, and dimensionless ecological function, as the optimization objectives. The impacts of the irreversible losses on the optimization results are analyzed. The results indicate that four objective functions increase as the compressor and turbine efficiencies increase. The influences of the latter efficiency on the cycle performances are more significant than those of the former efficiency. Then, the NSGA-II algorithm is applied for multi-objective optimization, and three different decision methods are used to select the optimal solution from the Pareto frontier. The results show that the dimensionless power density and dimensionless ecological function compromise dimensionless power output and thermal efficiency. The corresponding deviation index of the Shannon Entropy method is equal to the corresponding deviation index of the maximum ecological function.
45 citations
TL;DR: In this paper, an irreversible thermionic refrigerator model based on van der Waals heterostructure with various irreversibilities is established by utilizing combination of non-equilibrium thermodynamics and finite time thermodynamics.
Abstract: In this paper, an irreversible thermionic refrigerator model based on van der Waals heterostructure with various irreversibilities is established by utilizing combination of non-equilibrium thermodynamics and finite time thermodynamics. The basic performance characteristics of the refrigerator are obtained. The effects of key factors, such as bias voltages, Schottky barrier heights and heat leakages, on the performance are studied. Results show that cooling rates and coefficients of performances (COPs) can attain the double maximum with proper modulation of barrier heights and bias voltages. Increasing cross-plane thermal resistance as well as decreasing electrode-reservoir thermal resistance and reservoir-reservoir thermal resistance can enhance the performance of the device. The optimal performance region is the interval between the maximum cooling rate point and the maximum COP point. By modulating the bias voltage, the working state of the device can fall into the optimal performance region. The optimal performance of the refrigerator when using single layer graphene and a few layers graphene as electrode material is also compared.
43 citations
TL;DR: In this paper, a bilinear interpolation algorithm is introduced to analyze the waste heat sources of the CNG engine and the thermodynamic, economic, and environmental performances of the DORC system.
37 citations
TL;DR: In this article , the optimal configurations of the membrane reactor of steam methane reforming (MR-SMR) for two optimization objectives, that is, heat exchange rate minimization and power consumption minimization, were obtained.
35 citations
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TL;DR: Entropy generation minimization (finite time thermodynamics, or thermodynamic optimization) is the method that combines into simple models the most basic concepts of heat transfer, fluid mechanics, and thermodynamics as mentioned in this paper.
Abstract: Entropy generation minimization (finite time thermodynamics, or thermodynamic optimization) is the method that combines into simple models the most basic concepts of heat transfer, fluid mechanics, and thermodynamics. These simple models are used in the optimization of real (irreversible) devices and processes, subject to finite‐size and finite‐time constraints. The review traces the development and adoption of the method in several sectors of mainstream thermal engineering and science: cryogenics, heat transfer, education, storage systems, solar power plants, nuclear and fossil power plants, and refrigerators. Emphasis is placed on the fundamental and technological importance of the optimization method and its results, the pedagogical merits of the method, and the chronological development of the field.
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TL;DR: In this paper, the authors propose a model of the natural form, questioning, and theory of the human body and the structure of a human body in terms of the following: 1. Natural Form, questioning and theory 2. Mechanical structure 3. Thermal structure 4. Heat trees 5. Fluid trees 6. Ducts and rivers 7. Turbulent structure 8. Convective trees 9. Structure in time: rhythm 11. Transportation and economics structure 12. Shapes with constant resistance
Abstract: 1. Natural form, questioning, and theory 2. Mechanical structure 3. Thermal structure 4. Heat trees 5. Fluid trees 6. Ducts and rivers 7. Turbulent structure 8. Convective trees 9. Structure in power systems 10. Structure in time: rhythm 11. Transportation and economics structure 12. Shapes with constant resistance About the author Author index Subject index.
1,195 citations
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23 Feb 2000TL;DR: In this article, the authors introduce heat exchangers -introduction, classification and selection heat exchanger thermohydraulic and thermodynamic properties of heat exchange, and design of shell and tube heat exchange.
Abstract: Heat exchangers - introduction, classfication and selection heat exchanger thermohydraulic fundamentals heat exchanger design compact heat exchangers shell and tube heat exchanger design regenerators plate heat exchangers and spiral plate heat exchangers heat-transfer augmentation fouling flow-induced vibration of shell and tube heat exchangers mechanical design of shell and tube heat exchangers corrosion material selection and fabrication quality control and quality assurance and nondestructive testing heat exchanger fabrication
998 citations
TL;DR: In this paper, the authors developed a solution to the fundamental problem of how to collect and "channel" to one point the heat generated volumetrically in a low conductivity volume of given size.
771 citations