Academic literature on the topic 'PISTON EXPANDER'

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Journal articles on the topic "PISTON EXPANDER"

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Wang, Wei, Yu Ting Wu, Chong Fang Ma, and Jian Yu. "Efficiency Analysis on Low Temperature Energy Conversion System Based on Organic Rankine Cycle." Advanced Materials Research 347-353 (October 2011): 498–503. http://dx.doi.org/10.4028/www.scientific.net/amr.347-353.498.

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The amount of low temperature heat resources is very huge, efficient utilization that energy is very important issue for improving energy efficiency, saving energy and protecting environment. Due to the small available energy of low temperature heat source, how to improve thermodynamic efficiency is the key problem. In this paper, the thermodynamic model of low temperature thermal power conversion system based on organic Rankine cycle was described firstly. Turbine, single screw and piston expanders were briefly described. R123, R245fa and R134a were chose as working fluid because of quite different critical temperature. Based on this model, the influence of thermodynamic property of organic working fluid on the efficiency of low temperature thermal power conversion system was discussed. The calculating result showed that R123 is the best choice if no considering the impact of expander types and that R245fa is the best choice if considering the impact of expander. This conclusion indicated that it is very important to investigate the match relationship between working fluid and expander. Moreover, single screw expander was proved to be more suitable than turbine and piston expanders for low temperature heat power conversion system.
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Panesar, Angad S., and Marco Bernagozzi. "Two-Phase Expander Approach for Next Generation of Heat Recovery Systems." International Journal of Renewable Energy Development 8, no. 3 (October 25, 2019): 203–13. http://dx.doi.org/10.14710/ijred.8.3.203-213.

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This study presents the numerical adaptations to the semi-empirical expander model in order to examine the feasibility of piston expanders under off-design and two-phase scenarios. This expander model considers supply valve pressure drop, condensation phenomena, heat losses, leakage losses and friction losses. Using Aspen HYSYS©, the expander model is utilised in simulating the next generation of integrated engine cooling and exhaust heat recovery system for future heavy-duty engines. The heat recovery system utilises water-propanol working fluid mixture and consists of independent high pressure (HP) and low pressure (LP) expander. The results of off‑design and two-phase operation are presented in terms of expander efficiency and the different sources of loss, under two distinctive engine speed-load conditions. The heat recovery system, operating with the LP expander at two-phase and the HP expander at superheated condition, represented the design point condition. At the design point, the system provided 15.9 kW of net power, with an overall conversion efficiency of 11.4%, representing 10% of additional engine crankshaft power. At the extreme off-design condition, the two-phase expander operation improved the system performance as a result of the nullification of leakage losses due to the much denser working fluid. The optimised two-phase operation of the LP expander (x=0.55) and the HP expander (x=0.9) at the extreme-off design condition improved the system power by nearly 50% (17.4 vs. 11.7 kW) compared to the reference state. Finally, adapting piston air motors as two-phase expanders for experimental evaluation and reduction in frictional losses was a recommended research direction. ©2019. CBIORE-IJRED. All rights reserved
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Wu, Zhong, Hongguang Zhang, Zhongliang Liu, Guohong Tian, Xiaochen Hou, and Fubin Yang. "Force and energy analysis of single-piston free-piston expander—linear generator." Energy 251 (July 2022): 123926. http://dx.doi.org/10.1016/j.energy.2022.123926.

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Cha, Jeongmin, Jiho Park, Kyungjoong Kim, and Sangkwon Jeong. "Free-piston reciprocating cryogenic expander utilizing phase controller." IOP Conference Series: Materials Science and Engineering 171 (February 2017): 012079. http://dx.doi.org/10.1088/1757-899x/171/1/012079.

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Haiqing, Guan, Ma Yitai, and Li Minxia. "Some design features of CO2 swing piston expander." Applied Thermal Engineering 26, no. 2-3 (February 2006): 237–43. http://dx.doi.org/10.1016/j.applthermaleng.2005.05.011.

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Wu, Zhong, Hongguang Zhang, Zhongliang Liu, Xiaochen Hou, Jian Li, Fubin Yang, and Jian Zhang. "Experimental study on the performance of single-piston free-piston expander—linear generator." Energy 221 (April 2021): 119724. http://dx.doi.org/10.1016/j.energy.2020.119724.

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Smorodin, Anatoliy I., and Artur I. Gimadeev. "Optimization of a compressed gaseous CO2 energy recovery dry ice pelletizer." MATEC Web of Conferences 324 (2020): 02008. http://dx.doi.org/10.1051/matecconf/202032402008.

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The disadvantages of the existing dry ice electromechanical pelletizers have been revealed. A schematic flow diagram of the new dry ice energy recovery pelletizer and a carbon dioxide TS diagram with the processes of the new pelletizer have been presented. The functions of the diameter of the piston expander of the new dry ice pelletizer and dry ice pressing pressure depending on the pressure of compressed gaseous CO2 have been derived. The optimal diameters of a piston expander for the dry ice pelletizer have been determined.
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Patel, Raj C., Diego C. Bass, Ganza Prince Dukuze, Angelina Andrade, and Christopher S. Combs. "Analysis and Development of a Small-Scale Supercritical Carbon Dioxide (sCO2) Brayton Cycle." Energies 15, no. 10 (May 13, 2022): 3580. http://dx.doi.org/10.3390/en15103580.

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Carbon dioxide’s (CO2) ability to reach the supercritical phase (7.39 MPa and 304.15 K) with low thermal energy input is an advantageous feature in power generation design, allowing for the use of various heat sources in the cycle. A small-scale supercritical carbon dioxide (sCO2) power cycle operating on the principle of a closed-loop Brayton cycle is currently under construction at The University of Texas at San Antonio, to design and develop a small-scale indirect-fired sCO2 Brayton cycle, acquire validation data of the cycle’s performance, and compare the cycle’s performance to other cycles operating in similar conditions. The power cycle consists of four principal components: A reciprocating piston compressor, a heating source, a reciprocating piston expander to produce power, and a heat exchanger to dissipate excess heat. The work explained in the present manuscript describes the theory and analysis conducted to design the piston expander, heating source, and heat exchanger in the cycle. Theoretical calculations indicate that using sCO2 for the Brayton cycle generates 4.5 kW of power with the inlet pressure and temperature of 17.23 MPa and 358.15 K to the piston expander. Based on the fully isentropic conditions, the thermal efficiency of the system is estimated to be 12.75%.
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Preetham, B. S., and L. Weiss. "Investigations of a new free piston expander engine cycle." Energy 106 (July 2016): 535–45. http://dx.doi.org/10.1016/j.energy.2016.03.082.

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Burugupally, Sindhu Preetham, and Leland Weiss. "Design and performance of a miniature free piston expander." Energy 170 (March 2019): 611–18. http://dx.doi.org/10.1016/j.energy.2018.12.158.

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Dissertations / Theses on the topic "PISTON EXPANDER"

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Kodakoglu, Furkan. "Performance analysis on Free-piston linear expander." UNF Digital Commons, 2017. http://digitalcommons.unf.edu/etd/766.

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The growing global demand for energy and environmental implications have created a need to further develop the current energy generation technologies (solar, wind, geothermal, etc.). Recovering energy from low grade energy sources such as waste heat is one of the methods for improving the performance of thermodynamic cycles. The objective of this work was to achieve long-term steady state operation of a Free-Piston Linear Expander (FPLE) and to compare the FPLE with the currently existing expander types for use in low temperature energy recovery systems. A previously designed FPLE with a single piston, two chambers, and linear alternator was studied and several modifications were applied on the sealing and over expansion. An experimental test bench was developed to measure the inlet and outlet temperatures, inlet and outlet pressures, flow rate, and voltage output. A method of thermodynamic analysis was developed by using the first and second law of thermodynamics with air as the working fluid. The experimental tests were designed to evaluate the performance of the FPLE with varying parameters of inlet air pressure, inlet air temperature, and electrical resistance. The initial and steady-state operation of the FPLE were successfully achieved. An uncertainty analysis was conducted on the measured values to determine the accuracies of the calculated parameters. The trends of several output parameters such as frequency, average root mean square (RMS) voltage, volumetric efficiency, electrical-mechanical conversion efficiency, isentropic efficiency, irreversibility, actual expander work, and electrical power were presented. Results showed that the maximum expander frequency was found to be 44.01 Hz and the frequency tended to increase as the inlet air pressure increased. The FPLE achieved the maximum isentropic efficiency of 21.5%, and produced maximum actual expander work and electrical work of 75.13 W and 3.302 W, respectively.
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Jones, Ryan Edward 1974. "Design and testing of experimental free-piston cryogenic expander." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/80237.

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Chaudhry, Gunaranjan. "Modelling of a floating piston expander employed in a 10 K cryocooler." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/33903.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.
Includes bibliographical references (p. 81).
A single stage of a 3-stage Collins-type cryocooler designed to provide I W of cooling at 10 K was constructed and tested. A single stage of the cryocooler consists of a compressor, a counter-flow heat exchanger, and an expander to expand the working fluid. The work of the expanding cold gas is transmitted up a floating piston and is dissipated by gas flows in and out of a warm volume. Flow through the cold volume is controlled by smart electromagnetic valves. Models were developed to describe the thermodynamic processes that make up the expander cycle. In the first iteration, models were developed to determine the equilibrium states at various points in the cycle by assuming the thermodynamic processes that made up the expander cycle to be quasi-static. These models were used to determine appropriate values of parameters such as the cut-off volume, the recompression volume, and warm end reservoir pressures for expander operation. Experiments were done to determine the efficiency of the floating-piston expander. Tests were also done to determine the characteristics of the heat exchanger and compare them with the design characteristics. Finally, the stage was run as a refrigerator with zero heat-load. It was observed that the quasi-static models did not adequately describe the performance of the expander as most of the processes did not go to equilibrium.
(cont.) Therefore, these models were improved by incorporating the dynamics of the piston motion, the fluid flow through the warm and cold volumes, and the fluid flow through the high-pressure passages of the heat exchanger.
by Gunaranjan Chaudhry.
S.M.
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Hogan, Jake (Jake R. ). "Development of a floating piston expander control algorithm for a Collins-type cryocooler." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/70459.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 96).
The multi-stage Collins-type cryocooler uses a floating piston design for the working fluid expansion in each stage. The piston floats between a cold volume, where the working fluid is expanded, and a warm volume. The piston's motion is controlled by opening and closing valves connecting several reservoirs at various pressures to the warm volume. Ideally, these pressures should be distributed between the high and low system pressure to gain good control of the piston motion. In past prototypes, helium flow through the piston-cylinder gap resulted in a loss of pressure in the reservoirs causing the piston to become immobile. A more complex control algorithm is required to maintain a net zero helium flow through this gap to allow for steady expander operation. A numerical quasi-steady thermodynamic model is developed for the piston cycle. The model determines the steady state pressure distribution of the reservoirs for an ideal expander with no helium flow through the piston-cylinder gap. This pressure distribution is dependent on the total mass of helium in pressure reservoirs as well as the points at which the warm helium intake as well as the cold helium exhaust end. The pressures in the pressure reservoirs show varying levels of dependence on the lengths of the intake and exhaust strokes. The model is extended to include helium flow through the gap and the inertia of the piston. The model is then used to determine how helium can be added to or removed from the reservoirs in the case that there is too much helium flow through the gap. These results are then integrated into a control algorithm that maintains zero net mass flow through the gap in each expander stage.
by Jake Hogan.
S.M.
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Dib, Ghady. "Thermodynamic simulation of compressed air energy storage systems." Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEI092.

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Le développement des énergies renouvelables pose la question du stockage de l’énergie électrique. L’utilisation du stockage par air comprimé semble une solution prometteuse dans le domaine du stockage d'énergie : elle se caractérise par une grande fiabilité, un faible impact environnemental et une remarquable densité énergétique stockée (kWh/m3). Jusqu’à présent, l'air comprimé a été utilisé dans de nombreux domaines comme vecteur d’énergie pour stocker différentes formes d'énergies (transport routier, poste pneumatique, plongée sous-marine). Néanmoins, actuellement de nombreux chercheurs se concentrent sur le développement de stockage d'énergie par air comprimé (CAES) à petite échelle couplé à une application de bâtiment en se basant sur les travaux développés pour les multiples systèmes de CAES à grande échelle installés dans le monde. Un modèle numérique global du système de stockage par air comprimé à petite échelle, couplé à un modèle de bâtiment et à des modules d’énergie renouvelable a été développé dans le but de modéliser différents compresseurs/détendeurs et structures d’installation développés par plusieurs startups (LightSail Energy et Enairys Powertech) et chercheurs. Les compresseurs et détendeurs adiabatiques ont d’abord été sélectionnés pour étudier le système de trigénération de stockage d'énergie par air comprimé adiabatique avancé (AA-CAES) couplé au bâtiment et aux réseaux avec les différents scénarios décrits ci-dessus. Les compresseurs et détendeurs quasi-isothermes développés par LightSail Energy et Enairys Powertech ont été modélisés pour chaque phase de la compression et de la détente. Ces modèles analytiques ont permis une meilleure compréhension du fonctionnement principal de ces technologies et d'avoir l’ordre de grandeur de différents paramètres physiques. Les systèmes I-CAES et AA-CAES sont comparés d'un point de vue financier en se référant à une analyse du marché des systèmes de production/utilisation de l'air comprimé. Trois prototypes différents ont été étudiés: deux systèmes AA-CAES (idéal et virtuel (basés sur des unités commerciales trouvées sur le marché de l'air comprimé)) et un système I-CAES (basé sur le prototype LightSail Energy CAES)
In the context of developing renewable energies, storing energy improves energy efficiency and promotes the insertion of intermittent renewable energies. It consists of accumulating energy for later use in a place that may be the same or different from the place of production. Converting electrical energy to high-pressure air seems a promising solution in the energy storage field: it is characterized by a high reliability, low environmental impact and a remarkable stored energy density (kWh/m3). Currently, many researchers are focusing on developing small scale of the compressed air energy storage system (CAES) coupled to a building applications based on the work done for multiple large scale CAES systems installed in the world. A global numerical model of trigeneration CAES system coupled to a building model and renewable energy modules was developed in order to analyze the CAES system behavior responding to electrical, hot and cold energy building demand. Different energy scenarios (autonomous and connected to the grid modes), geographical locations and building typologies were proposed and analyzed. The CAES numerical model development is based on solving energy and heat transfer equations for each system component (compressor/expander, heat exchanger, high pressure air reservoir, thermal water storage tank). Adiabatic compressor and expander were firstly selected to investigate the trigeneration advanced adiabatic compressed air energy system (AA-CAES) coupled to the building and to grids with the different scenarios described above. Similar to adiabatic components, quasi-isothermal compressor and expander developed by LightSail Energy and Enairys Powertech were also analyzed by solving the energy and heat transfer equations for each phase of the compression and expansion processes. These analytical models allowed us to have a better understanding of these technologies operations and to have several orders of magnitudes of different physical parameters. I-CAES and AA-CAES were also compared from a financial point of view based on compressed air market analysis. Three different prototypes were studied: Two AA-CAES systems (ideal and virtual (some of which are based on commercial units found in the compressed air market)) and one I-CAES system (based on LightSail Energy CAES prototype)
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Tokař, Stanislav. "Mechanismus jednoválcového zážehového motoru s prodlouženou expanzí." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2009. http://www.nusl.cz/ntk/nusl-228842.

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This thesis concentrates on the design of crank-type mechanism of engine with elongated expansion. The main attention is paid to examination of the progress of kinematic quantities and inertial forces in mechanism. Further on in the thesis, the analysis of piston-rod stress is carried out and is compared to the piston-rod of standard engine. In the last part of the thesis, there is an evaluation of advantages and disadvantages of the proposed mechanism solution.
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GALOPPI, GIOVANNI. "DEVELOPMENT OF A RADIAL PISTON EXPANDER FOR VAPOR COMPRESSION CYCLES." Doctoral thesis, 2017. http://hdl.handle.net/2158/1082547.

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In recent years, heat pumps and refrigeration systems are widely used in both residential and industrial applications. The possibility of recovering the large throttling losses by using an expander could give a substantial contribution to the performance improvement. In this thesis, a reciprocating expander developed from a hydraulic motor was numerically and experimentally analyzed. A numerical model was developed to identify the needed small modifications to be made on the expander without change its architecture. Successively, an extensive experimental activity on the modified expander has been carried out to characterize it in detail and evaluate the effective performance. With this aim, a dedicated test rig and a measurement system have been developed. The expander was tested in a R134a heat pump cycle and in a CO2 refrigeration cycles. Despite of the mechanical losses due to the different original application of the machine, the thermodynamic cycles showed very promising results with the adoption of this solution. For this reason, a redesign and manufacturing of the machine was done in order to improve the efficiency in HFC cycles and to decrease the mechanical losses. The new version of the expander was tested in a "hot-gas bypass cycle", which has been designed and manufactured. The aim of this cycle is to obtain high stability and flexibility, and lower size due to the lack of the evaporator. The results showed improvement in both the thermodynamic behavior and mechanical losses. Finally, a 1D thermal conduction model has been developed to study the two-phase expansion with R134a with an improved accuracy.
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Books on the topic "PISTON EXPANDER"

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Bailey, P. B. A free piston expander for a direct fired Rankine cycle heat pump. [s.l.]: typescript, 1986.

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Roberts, Joseph Boxley. Firearms Assembly : The NRA Guide to Rifles and Shotguns (Revised and Expanded) (Item #01600) (Revised and Expanded). Natl Rifle Assn, 1993.

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Derby, Harry. Japanese Military Cartridge Handguns 1893-1945: A Revised and Expanded Edition of Hand Cannons of Imperial Japan. Schiffer Publishing, 2007.

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David Joseph, Attard, Fitzmaurice Malgosia, and Ntovas Alexandros XM, eds. The IMLI Treatise On Global Ocean Governance. Oxford University Press, 2018. http://dx.doi.org/10.1093/law/9780198823964.001.0001.

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In 1994, a long-debated compromise on the issue of seabed mining became the starting pistol for the development of modern ocean law and its complex interrelations. Now, over twenty years later, the framework set by such agreements as the 1982 United Nations Convention on the Law of the Sea (UNCLOS) has been expanded to cover contemporary concerns of environmental sustainability, economic development, social justice, human rights, security, marine pollution, and even the challenges of climate change. Yet the journey is not smooth. This book forms part of a three-volume series that looks to examine the more successful ocean law schemes and the less effective, and presses the need for change, as scientific and technological innovation, the surge in human population, and pressing moral concerns open new spaces for ocean law. In the second volume in the series, autonomous organisations working under the auspices of the UN are the target, from the World Intellectual Property Organization to the United Nations Office on Drugs and Crime: are they ensuring sustainable development, are efforts adequately administrated, and how much co-ordination is there between different legal bodies?
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Prieto, Hernán. Lecciones de teoría política: la democracia de los atenienses entre la stásis y la diálysis. Universidad Libre Sede Principal, 2020. http://dx.doi.org/10.18041/978-958-5578-29-6.

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La carne del país (Brasil, pero también Colombia y tantos otros) se desgarra y se zurce, se deshilacha y se vuelve a coser, una y otra vez, hasta que, por más abnegadas que sean las mujeres, la mano, la aguja y el hilo, ya no pueden más, “porque se había matado demasiado”. ¿Qué hacer? ¿Sí, qué hacer los que no sabemos, ni queremos, matar? Para los que en cambio sí sabemos que “matar un hombre por defender una idea, no es defender una idea sino matar un hombre” (Castello contra Calvino, de Zweig) ¿Qué hacer? Aprender de los matemáticos: «comencemos con las ecuaciones diferenciales parciales con frontera libre. Imagínese que hay una represa con muros, se rompe y empieza a regarse el agua. El suelo alrededor comienza a mojarse. Una frontera libre es esa frontera entre el piso seco y el mojado. Los matemáticos queremos saber a qué velocidad se expande, y otras características para tratar de contener y prever qué va a ocurrir para detenerla». Así nos enseña, a los no iniciados, la gran matemática colombiana Tatiana Toro. ¿Qué hacer cuando una represa se rompe y empieza a inundarlo todo? Aprender a qué velocidad se expande, entre muchísimas otras cosas, para tratar de contener el daño y saber qué es lo que hay que hacer para detener la catástrofe. Una «frontera libre», en política, sería esa delgada línea situada entre matones y asesinos de ambos lados, para decirles a los unos y a los otros: «no pasarán». Eso fue lo que enseñó hace más de dos mil quinientos años atrás Solón, el sabio poeta en torno al cual gira la invención de la política en su versión ateniense. Cuando terminó su labor de palabrero, ¿cómo quiso ser recordado? No hice viudas a las mujeres, no cercené la vida de los jóvenes. ¿Qué gobernantes, qué políticos, de uno y otro bando pueden decir algo que alcance a las plantas de los pies de Solón?
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Book chapters on the topic "PISTON EXPANDER"

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Jones, R. E., and J. L. Smith. "Design and Testing of Experimental Free-Piston Cryogenic Expander." In Advances in Cryogenic Engineering, 1485–92. Boston, MA: Springer US, 2000. http://dx.doi.org/10.1007/978-1-4615-4215-5_68.

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Daccord, Rémi, Julien Melis, Antoine Darmedru, Edouard Davin, Antoine Debaise, Brice Mandard, Alexandre Bouillot, Stéphane Watts, and Xavier Durand. "Integration of a Piston Expander for Exhaust Heat Recovery in a Long Haul Truck." In Energy and Thermal Management, Air Conditioning, Waste Heat Recovery, 53–62. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-47196-9_5.

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Subiantoro, Alison, and Kim Tiow Ooi. "Expansion Power Recovery in Refrigeration Systems." In Handbook of Research on Advances and Applications in Refrigeration Systems and Technologies, 720–51. IGI Global, 2015. http://dx.doi.org/10.4018/978-1-4666-8398-3.ch019.

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Vapor-compression systems are the most popular method of refrigeration. However, the throttling loss at the expansion valve is one of the “energy parasites” of such systems. This is especially acute in systems with large operating pressure differences like the transcritical CO2 refrigeration systems. In this chapter, a method to solve this issue by using an expander to recover the expansion energy of refrigeration systems is explained. Relevant research works are then discussed to provide a general overview about the state of the art technology. Various types of expander mechanisms, including reciprocating, rolling piston, rotary vane, scroll, screw, turbine, swing piston and revolving vane, are discussed. Works on the various aspects of expanders are also discussed. These include heat transfer, exergy analysis, expansion process, internal leakage, lubrication, integration with refrigeration systems and the economic aspects.
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Mckenna, S., G. Mccullough, R. Douglas, and S. Glover. "Mathematical modelling of a reciprocating piston expander." In Vehicle Thermal Management Systems Conference Proceedings (VTMS11), 183–92. Elsevier, 2013. http://dx.doi.org/10.1533/9780857094735.4.183.

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Avery, William H., and Chih Wu. "Closed-Cycle OTEC Systems." In Renewable Energy from the Ocean. Oxford University Press, 1994. http://dx.doi.org/10.1093/oso/9780195071993.003.0011.

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The Rankine closed cycle is a process in which beat is used to evaporate a fluid at constant pressure in a “boiler” or evaporator, from which the vapor enters a piston engine or turbine and expands doing work. The vapor exhaust then enters a vessel where heat is transferred from the vapor to a cooling fluid, causing the vapor to condense to a liquid, which is pumped back to the evaporator to complete the cycle. A layout of the plantship shown in Fig. 1-2. The basic cycle comprises four steps, as shown in the pressure-volume (p—V) diagram of Fig. 4-1. 1. Starting at point a, heat is added to the working fluid in the boiler until the temperature reaches the boiling point at the design pressure, represented by point b. 2. With further heat addition, the liquid vaporizes at constant temperature and pressure, increasing in volume to point c. 3. The high-pressure vapor enters the piston or turbine and expands adiabatically to point d. 4. The low-pressure vapor enters the condenser and, with heat removal at constant pressure, is cooled and liquefied, returning to its original volume at point a. The work done by the cycle is the area enclosed by the points a,b,c,d,a. This is equal to Hc–Hd, where H is the enthalpy of the fluid at the indicated point. The heat transferred in the process is Hc–Ha Thus the efficiency, defined as the ratio of work to heat used, is: . . . efficiency(η)=Hc–Hd/Hc–Ha (4.1.1) . . . Carnot showed that if the heat-engine cycle was conducted so that equilibrium conditions were maintained in the process, that the efficiency was determined solely by the ratio of the temperatures of the working fluid in the evaporator and the condenser. . . . η=TE–Tc/TE (4.1.2) . . . The maximum Carnot efficiency can be attained only for a cycle in which thermal equilibrium exists in each phase of the process; however, for power to be generated a temperature difference must exist between the working fluid in the evaporator and the warm-water heat source, and between the working fluid in the condenser and the cold-water heat sink.
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Schwalbach, Jon R., and Kevin M. Bohacs. "An observational approach to mudstone sequence stratigraphy: The Monterey Formation of California." In Understanding the Monterey Formation and Similar Biosiliceous Units across Space and Time. Geological Society of America, 2022. http://dx.doi.org/10.1130/2022.2556(02).

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ABSTRACT Sequence stratigraphy has proven to be an invaluable tool for the analysis of coarse-clastic depositional systems and the integration of observations across scales from reflection seismic to scanning electron microscope. Applications to mudstone-dominated depositional sequences have been more limited, despite the fact that mudstones make up more than 60% of the global sedimentary volume and generally provide the most complete record of sedimentation in a basin. During the late 1970s and through the 1980s, Bob Garrison and his students at the University of California–Santa Cruz conducted numerous studies that revealed the basic sedimentary and stratigraphic framework of the Monterey Formation in California, advancing our understanding of the sedimentary processes at work in these deep-margin basins. We expanded on that framework using direct observations from outcrops and cores that have been integrated with other subsurface data, as well as a wide variety of information derived from paleontologic, chronostratigraphic, geochemical, and compositional analyses to illustrate a sequence-stratigraphic approach to interpreting fine-grained rocks and their associated depositional systems in these settings. These were some of the earliest investigations of mudstone sequence stratigraphy focused on slope and basinal environments. In this study, observations from outcrops in the Pismo Basin, California, provided the basis for developing a detailed sequence-stratigraphic framework for the Monterey Formation, expanding on the broad-scale characterization of Garrison and his colleagues. These outcrops represent deposition during different phases of basin evolution and in different borderland-type basin settings (slope and basin depocenters). Comparison of coeval strata from different depositional settings and locations documented variation at both the sequence and parasequence scale. Variation of parasequence character, in particular, provided a valuable tool for enhanced understanding of deposition and diagenesis in these margin basins. Extrapolation to the subsurface using gamma-ray logs greatly enhanced basinwide application compared to limited, partial-stratigraphic-section outcrops, and it facilitated the lateral characterization of mudstone depositional sequences. These elements served as the building blocks for improved models of deposition in margin-basin settings.
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Conference papers on the topic "PISTON EXPANDER"

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Smith, J. L., J. G. Brisson, M. J. Traum, C. Hannon, and J. Gerstmann. "Description of a High-Efficiency Floating-Piston Expander for a Miniature Cryocooler." In ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-33402.

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A cryogenic expander employing low-temperature helium is under development. This expander employs a floating piston operating between a warm variable volume and a cold variable volume to expand the working fluid. The piston’s position is dynamically regulated through an active control routine that actuates electromechanical valves. These valves control helium flow in and out of the variable volumes. Throttling through the warm-end valves regulates the piston’s velocity. The cold-end valves, operating at cryogenic temperatures, are of novel design to achieve system miniaturization and high efficiency at range of operating points.
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2

Kornhauser, Alan A. "Dynamics and Thermodynamics of a Free-Piston Expander-Compressor." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-63517.

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In a free-piston expander-compressor (FPEC) the work of an expanding gas or vapor is used to compress another gas or vapor through a direct connection of one piston-cylinder assembly to another, without rotary motion. Each section of the FPEC operates like the piston-cylinder of a shaft-connected reciprocating machine. The expander section operates like that of a steam engine: high-pressure gas or vapor is freely admitted through part of the expansion process, but stopped at the “cutoff” part way through the expansion. The compressor section is like that of a shaft-driven reciprocating compressor: low-pressure gas is admitted during the intake stroke, compressed during the compression stroke, and then discharged when it has reached the downstream high pressure. The design of an FPEC is complicated by the fact that the expander and compressor have different relationships between force and position. The force on the expander piston decreases as the stroke progresses, while that on the compressor piston increases. The force difference must be made up by momentum change of the pistons and connecting rod, which accelerate in the early part of the stroke and decelerate in the latter part. The balance between the expanding fluid, the moving mass, and the compressed fluid can be described either dynamically (force and momentum) or thermodynamically (work and energy). It is shown that the mechanical design (piston areas, stroke, oscillating mass, and frequency) of an idealized FPEC is highly constrained by the thermodynamics of the high-pressure stream expansion and the low-pressure stream compression. For simple cases, dynamic models in differential equation form can be compared to thermodynamic analyses in algebraic form. The thermodynamic models provide a baseline design point for an ideal FPSE. The dynamic models can then be used to study non-ideal cases.
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3

Chiong, Meng Choung, Srithar Rajoo, and Alessandro Romagnoli. "Nozzle Steam Piston Expander for Engine Exhaust Energy Recovery." In The 11th International Conference on Automotive Engineering. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2015. http://dx.doi.org/10.4271/2015-01-0126.

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4

Daccord, Rémi, Antoine Darmedru, and Julien Melis. "Oil-Free Axial Piston Expander for Waste Heat Recovery." In SAE 2014 World Congress & Exhibition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2014. http://dx.doi.org/10.4271/2014-01-0675.

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5

Champagne, C., and L. Weiss. "Investigation of a MEMS-Based Boiler and Free Piston Expander for Energy Harvesting." In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-86289.

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Initial investigations of a small-scale Free Piston Expander (FPE) are presented. In final form, the FPE will be a MEMS-based device capable of operation from low temperature waste heat sources. In this present study, a millimeter scale device is constructed and tested to yield insight into critical operational parameters. Different constructions and operating conditions are considered as are the effects on basic piston motion and performance. These include piston length and mass. In addition, different sealing and lubricating fluids are considered. Construction of this testbed device is via concentric copper tubing, allowing an effective baseline study of these determining parameters. Results show that, while thick lubricants seal well in a static test, piston motion is decreased in a dynamic test indicating leakages. By contrast, reduced viscosity lubricants dont seal as well in a static test, but yield increased piston motion in dynamic testing. This indicates effective sealing. The trends established by the study of varying viscosity lubricants hold true for pistons of increasing mass and length as well. A mixture of isopropanol and water performed well in these tests, and represented a low viscosity sealing fluid. Compared to conditions where no lubricant was used, maximum velocity was increased up to 50%. These results indicate that a thin, wetting fluid will be the best lubricant for the FPE, due to increased sealing and performance when in dynamic operation.
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6

Champagne, C., and L. Weiss. "Design and Optimization of Free Piston Expander for Energy Harvesting." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-64798.

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There is a growing opportunity and need for research that investigates alternate power sources. One such source is low temperature waste heat, or energy cast off to the environment as part of some larger process. Through the capture and use of this abundant energy source for power production, it is possible to enhance the overall operating efficiency of the larger system. This presents significant potential for sustainability increase and energy savings. One potential system that can operate from these sources is a low temperature, small-scale steam expander. Investigations of one such device called a Free Piston Expander (FPE) are presented in this work. In final form, the FPE will be a MEMS based device capable of operation as part of a complete low temperature steam system. In this present study, a millimeter scale device is constructed and tested to yield insight into critical operational parameters for future microfabricated designs. Construction of this testbed device is via concentric copper tubing, allowing an effective baseline study of these determining parameters. Parameters studied include device cross sectional area and shape as well as operational pressure. Once consistent parameters are determined, three separate variations of circular FPE design are further tested. These FPEs are designed to either constrain piston rotation or allow for rotational freedom during operation. Testing is performed on these devices for consistency in piston motion. Piston motion is characterized based on a single expansion and reaction of the piston.
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Schmitt, Joshua, and Jordan Nielson. "Modeling and Testing of a Novel Ultra-Low Temperature sCO2 Opposing Piston Expander." In ASME Turbo Expo 2021: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/gt2021-60251.

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Abstract Southwest Research Institute (SwRI) along with Thermal Tech Holdings (TTH) have modeled, built, and tested a piston expander for generating power from low temperature heat sources. The piston was developed with the goal of creating an engine that operates as a recuperated sCO2 Ericsson cycle. A cycle model based on fluid properties from REFPROP is applied for various hot and cold temperatures to demonstrate the potential of the novel expander to improve cycle efficiency. Cycle modeling results demonstrate the potential improvements in cycle efficiency when compared to the sCO2 Brayton cycle. Small-scale bench testing is used to validate the novel piston concept for achieving a sCO2 Ericsson cycle. The concept is scaled up to a full-sized, opposing piston cylinder that acts as an expander in the theoretical Ericsson cycle. Testing is performed on the full-scale piston cylinder for a variety of inlet temperatures and pressures. The full-scale tests are run continuously to track the transient effects. The results of the full-scale test are discussed. The expander piston cylinder test results show high temperatures at the outlet, better than the ideal sCO2 Brayton cycle, but less than an ideal recuperated sCO2 Ericsson cycle. Comparisons are made to demonstrate the projected cycle efficiency improvements over a sCO2 Brayton cycle.
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Peng, Baoying, Kai Zhang, Pengjia Wang, and Liang Tong. "Research on Constant Load of Double Acting Free Piston Expander-Linear Generator." In 2022 5th International Conference on Energy, Electrical and Power Engineering (CEEPE). IEEE, 2022. http://dx.doi.org/10.1109/ceepe55110.2022.9783277.

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9

Fiaschi, Daniele, Riccardo Secchi, Giovanni Galoppi, Duccio Tempesti, Giovanni Ferrara, Lorenzo Ferrari, and Sotirios Karellas. "Piston Expanders Technology as a Way to Recover Energy From the Expansion of Highly Wet Organic Refrigerants." In ASME 2015 9th International Conference on Energy Sustainability collocated with the ASME 2015 Power Conference, the ASME 2015 13th International Conference on Fuel Cell Science, Engineering and Technology, and the ASME 2015 Nuclear Forum. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/es2015-49427.

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The design of expanders for organic fluids is gaining an increasing attention due to the large opportunities opened by the ORC as a way to recover low grade heat. The possibility of recovering at least a fraction of the energy related to throttling in inverse cycles could have interesting relapses on the market of heating (heat pumps) and refrigeration machines. The main challenge to be faced is the management of a highly wet fluid (typical quality is in the 0–0.6 range), which puts off side dynamic expanders like turbines. For this reason, piston technology is proposed and analyzed. The potential recovery from the throttling of a 20 kW target domestic heat pump cycle is determined by modeling the real expansion cycle with two different codes, a commercial one (largely widespread and very easy to use) and a purposely developed one, which is much more customizable and may include different approaches to the physical behavior of the two–phase expansion. The results show interesting possibility of energy recovery from this generally wasted source, which opens the way to improvements of the heat pump COP from 4% to about 7%, depending on the working (i.e. seasonal) conditions. The analysis also points out the agreement in the results of two different adopted simulation tools (commercial AMESim® and self-made customizable EES®), which can be thus considered valuable in the design, analysis and optimization of the proposed expander. Due to the biphasic nature of the working fluid, the performance of the expander is strongly influenced by the inlet conditions of the fluid from the condenser of the heat pump to the cylinders, such as throttling of the inlet/outlet valves and friction through the ducts. On the whole, this expander technology has very interesting chances to effectively manage fluids under highly wet conditions, like those related to the throttling from upper to lower pressure of inverse cycles.
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10

Saadat, Mohsen, Farzad A. Shirazi, and Perry Y. Li. "Nonlinear Controller Design With Bandwidth Consideration for a Novel Compressed Air Energy Storage System." In ASME 2013 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/dscc2013-4069.

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Maintaining the accumulator pressure regardless of its energy level and tracking the power demanded by the electrical grid are two potential advantages of the Compressed Air Energy Storage (CAES) system proposed in [1, 2]. In order to achieve these goals, a nonlinear controller is designed motivated by an energy-based Lyapunov function. The control inputs of the storage system include displacement of the pump/motor in the hydraulic transformer and displacement of the liquid piston air compressor/expander. While the latter has a relatively low bandwidth, the former is a faster actuator with a higher bandwidth. In addition, the pneumatic path of the storage vessel that is connected to the liquid piston air compressor/expander has a high energy density, whereas the hydraulic path of the storage vessel is power dense. The nonlinear controller is then modified to achieve a better performance for the entire system according to these properties. In the proposed approach, the control effort is distributed between the two pump/motors based on their bandwidths: the hydraulic transformer reacts to high frequency events, while the liquid piston air compressor/expander performs a steady storage/regeneration task. As a result, the liquid piston air compressor/expander will loosely maintain the accumulator pressure ratio and the pump/motor in the hydraulic transformer will precisely track the desired generator power. This control scheme also allows the accumulator to function as a damper in the storage system by absorbing power disturbances from the hydraulic path generated by wind gusts.
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