Gotowe bibliografie tematyczne / Low temperature heat engine

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Gotowa bibliografia na temat „Low temperature heat engine”

Autor: Grafiati
Data publikacji: 4 czerwca 2021
Data aktualizacji: 19 lutego 2022

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Artykuły w czasopismach na temat "Low temperature heat engine"

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Chen, Lingen, Shengbing Zhou, Fengrui Sun i Chih Wu. "Optimal Configuration and Performance of Heat Engines with Heat Leak and Finite Heat Capacity". Open Systems & Information Dynamics 09, nr 01 (marzec 2002): 85–96. http://dx.doi.org/10.1023/a:1014235029474.

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The optimal configuration of a class of two-heat-reservoir heat engine cycles in which the maximum work output can be obtained under a given cycle time is determined with the considerations of heat leak, finite heat capacity high-temperature source and infinite heat capacity low-temperature heat sink. The heat engine cycles considered in this paper include: (1) infinite low- and high-temperature reservoirs without heat leak, (2) infinite low- and high-temperature reservoirs with heat leak, (3) finite high-temperature source and infinite low-temperature sink without heat leak, and (4) finite high-temperature source and infinite low-temperature sink with heat leak. It is assumed that the heat transfer between the working fluid and the reservoirs obeys Newton's law. It is shown that the existence of heat leak doesn't affect the configuration of a cycle with an infinite high-temperature source. The finite heat capacity of a high temperature source without heat leak makes the cycle a generalized Carnot heat engine cycle. There exists a great difference of the cycle configurations for the finite high-temperature source with heat leak and the former three cases. Moreover, the relations between the optimal power output and the efficiency of the former three configurations are derived, and they show that the heat leak affects the power versus efficiency characteristics of the heat engine cycles.
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Rokhmawati, Endang Dian, Irna Farikhah, Ummi Kaltsum, Harto Nuroso, Aan Burhanudin, Yuris Setyoadi, Muhammad Amiruddin i Irfan Abd Rahim. "Numerical Study on the Effect of Mean Pressure and Loop's Radius to the Onset Temperature and Efficiency of Traveling Wave Termoacustic Engine". Automotive Experiences 3, nr 3 (30.09.2020): 96–103. http://dx.doi.org/10.31603/ae.v3i3.3881.

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The thermoacoustic engine can be a device to convert waste heat energy in the engine car become useful energy such as for charging battery in car or Air conditioner of the car. This work can be done by experimentally and numerically. There are some parameters that have an impact on the performance of the engine. They are geometry of the engines, working fluid, and mean pressure. The performance of the engine depends on the efficiency and the heating temperature. In the car, waste heat energy is not high enough. Therefore, we need to utilize the low heating temperature to be converted into useful energy. This study contributes to numerically the effect of mean pressure and loop’s radius of the regenerator on the onset temperature and the efficiency of traveling wave thermoacoustic engines. The application that is used to solve numerical problems is fortran95. There are two codings that are used in fortran95. They are stability limits and efficiency codes. The lowest onset temperature that achieved is 153˚C with efficiency up to 38.1% that can be reached when the mean pressure is 4.0 MPa and the loop's radius is 5 cm. This result indicated that we can use low heating temperatures from waste heat of engine car to turn on electronics equipment inside the car.
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Likos, W. E., i T. W. Ryan. "Experiments With Coal Fuels in a High-Temperature Diesel Engine". Journal of Engineering for Gas Turbines and Power 110, nr 3 (1.07.1988): 444–52. http://dx.doi.org/10.1115/1.3240141.

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The combustion of 50 wt percent coal slurries, using water, diesel fuel, and methanol as carrier liquids, was investigated in a single-cylinder research engine. High temperatures were achieved in the engine cylinder using low-heat-rejection engine technology, electrically heated glow plugs, and heated inlet air. Comparisons of the fuels and different methods of providing high cylinder temperature were made using cylinder pressure data and heat release calculations. Autoignition of the coal/water slurries was attained using auxiliary heat input. The burning rates of all the autoignited slurries were significantly enhanced by using a pilot injection of diesel fuel. Under some operating conditions the engine thermal efficiency was equal to diesel fuel performance. It was apparent that engines designed for coal slurry should maximize the prechamber volume.
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Reddy, Ch Kesava, M. V. S. Murali Krishna, P. V. K. Murthy i T. Ratna Reddy. "Performance Evaluation of a Low-Grade Low-Heat-Rejection Diesel Engine with Crude Pongamia oil". ISRN Renewable Energy 2012 (15.03.2012): 1–10. http://dx.doi.org/10.5402/2012/489605.

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Investigations are carried out to evaluate the performance of a low heat rejection (LHR) diesel engine with ceramic coated cylinder head [ceramic coating of thickness 500 microns is done on inside portion of cylinder head] with different operating conditions [normal temperature and pre-heated temperature] of crude Pongamia oil (CPO) with varied injection pressure and injection timing. Performance parameters and pollution levels are determined at various magnitudes of brake mean effective pressure. Combustion characteristics at peak load operation of the engine are measured with special pressure-crank angle software package. Conventional engine (CE) showed deteriorated performance, while LHR engine showed improved performance with CPO operation at recommended injection timing and pressure and the performance of both version of the engine is improved with advanced injection timing and at higher injection pressure when compared with CE with pure diesel operation. The optimum injection timing is 31°bTDC for conventional engine while it is 29°bTDC with LHR engine with vegetable oil operation. Peak brake thermal efficiency increased by 5%, smoke levels decreased by 2% and NOx levels increased by 40% with CPO operation on LHR engine at its optimum injection timing, when compared with pure diesel operation on CE at manufacturer’s recommended injection timing.
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Mekhtiyev, A. D., V. V. Yugay, A. D. Alkina, Y. G. Neshina i D. E. Kapanova. "Studying a low-temperature engine with external heat supply". Journal of Physics: Conference Series 1843, nr 1 (1.03.2021): 012006. http://dx.doi.org/10.1088/1742-6596/1843/1/012006.

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Petkovic, Snezana, Radivoje Pesic i Jovanka Lukic. "Heat transfer in exhaust system of a cold start engine at low environmental temperature". Thermal Science 14, suppl. (2010): 209–20. http://dx.doi.org/10.2298/tsci100505070p.

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During the engine cold start, there is a significantly increased emission of harmful engine exhaust gases, particularly at very low environmental temperatures. Therefore, reducing of emission during that period is of great importance for the reduction of entire engine emission. This study was conducted to test the activating speed of the catalyst at low environmental temperatures. The research was conducted by use of mathematical model and developed computer programme for calculation of non-stationary heat transfer in engine exhaust system. During the research, some of constructional parameters of exhaust system were adopted and optimized at environmental temperature of 22?C. The combination of design parameters giving best results at low environmental temperatures was observed. The results showed that the temperature in the environment did not have any significant influence on pre-catalyst light-off time.
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Jiang, Wei Jiang. "The Study of Heat-Engines Based on Refrigerant Phase-Change Circulation". Applied Mechanics and Materials 66-68 (lipiec 2011): 649–53. http://dx.doi.org/10.4028/www.scientific.net/amm.66-68.649.

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This paper firstly introduces the principles of Stirling heat engines based on refrigerant phase-change circulation. This heat engines use two external heat reservoire. When the refrigerant in an engine cylinder absorbs heat from high-temperature heat sources, refrigerant is transformed from liquid to gas and the volume of the refrigerant expands to drive the piston apply work. When the refrigerant releases heat to low-temperature sources, the volume of the refrigerant shrinks. Therefore, phase change thermal engine technology using solar energy, industrial waste heat and heat produced by combustion of any fuel to work, no gas emissions, high thermal efficiency and environmental advantages. Thermal phase transition and thus the engine technology will be in the field of energy and power of a cutting-edge technology, great development potential and prospects.
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Chérel, Jérôme, Jean-Marc Zaccardi, Bernard Bouteiller i Alain Allimant. "Experimental assessment of new insulation coatings for lean burn spark-ignited engines". Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles 75 (2020): 11. http://dx.doi.org/10.2516/ogst/2020006.

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Clean and highly efficient internal combustion engines will still be necessary in the future to meet the ambitious CO2 emissions reduction targets set for light-duty vehicles. The maximal efficiency of stoichiometric Spark-Ignited (SI) gasoline engines has been steadily increasing in recent years but remains limited by the important relative share of cooling losses. Low heat rejection engines using ceramic barrier coatings have been presented in the past but smart insulation coatings are gaining a renewed interest as a more promising way to further increase the engine maximal thermal efficiency. This article is highlighting some important effects of smart insulation coatings developed for lean-burn spark-ignited gasoline engines. Five different coatings with low heat conductivity and capacity are applied on aluminum engine parts with the atmospheric plasma spray technique and are tested with two different engines. The laser induced phosphorescence technique is firstly used in an optical single cylinder engine to quantify the thermal performance of these coatings in terms of temperature swing during combustion. A maximal increase in the piston surface temperature of around 100 °C is measured at low load, confirming thus the expected impact of the low heat conductivity and capacity, and suggesting thus a positive impact on fuel consumption. Thanks to the tests performed with a similar metal single cylinder engine, it is shown that the unburned hydrocarbon emissions can significantly increase by up to 25% if the open porosity on top of the coating is not properly sealed, while the surface roughness has no impact on these emissions. When applied on both the piston and the cylinder head, the optimized coating displays some distinct effects on the maximal heat release rate and NOx emissions, indicating that the thermal environment inside the combustion chamber is modified during combustion. Thanks to the temperature swing between cold and hot engine phases the volumetric efficiency can also be kept constant. However, no increase in efficiency can be measured with this optimized coating which suggests that the heat balance is not affected only by the reduction in the temperature differential between the walls and the gas.
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Kawaguchi, Akio, Yoshifumi Wakisaka, Naoki Nishikawa, Hidemasa Kosaka, Hideo Yamashita, Chikanori Yamashita, Hiroki Iguma, Kenji Fukui, Noriyuki Takada i Terutoshi Tomoda. "Thermo-swing insulation to reduce heat loss from the combustion chamber wall of a diesel engine". International Journal of Engine Research 20, nr 7 (10.06.2019): 805–16. http://dx.doi.org/10.1177/1468087419852013.

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Cooling heat loss is one of the most dominant losses among the various engine losses to be reduced. Although many attempts to reduce it by insulating the combustion chamber wall have been carried out, most of them have not been successful. Charge air heating by the constantly high temperature insulating wall is a significant issue, because it deteriorates charging efficiency, increases the emissions of soot and NOx in diesel engines, and promotes the knock occurrence tendency in gasoline engines. A new concept heat insulation methodology which can reduce cooling heat loss without heating the charging air has been developed. Surface temperature of insulation coating on the combustion chamber wall changes rapidly, according to the quickly changing in-cylinder gas temperature in each engine stroke. During the compression and expansion stroke, the surface temperature of the insulation coating goes up rapidly, and consequently, the heat transfer becomes lower by the reduced temperature difference between the surface and the gas. During the intake stroke, the surface temperature goes down rapidly, and it prevents intake air heating from the wall. To realize the above-mentioned functionality, a thin coating layer with low thermal conductivity and low heat capacity was developed. It was applied on the pistons of diesel engines, and showed improvement in thermal efficiency. It also showed a reduction of unburnt fuel emission in low temperature engine starting condition. The energy balance analysis showed reduction of cooling heat loss and, on the contrary, increase in the brake power and the exhaust loss.
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Amann, C. A. "Promises and Challenges of the Low-Heat-Rejection Diesel". Journal of Engineering for Gas Turbines and Power 110, nr 3 (1.07.1988): 475–81. http://dx.doi.org/10.1115/1.3240145.

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The low-heat-rejection (LHR) diesel promises decreased engine fuel consumption by eliminating the traditional liquid cooling system and converting energy normally lost to the coolant into useful shaft work instead. However, most of the cooling energy thus conserved is transferred into the exhaust stream rather than augmenting crankshaft output directly, so exhaust-energy recovery is necessary to realize the full potential of the LHR engine. The higher combustion temperature of the LHR diesel favors increased emission of NOx, with published results on hydrocarbon and particulate emissions showing mixed results. The cylinder insulation used to effect low heat rejection influences convective heat loss only, and in a manner still somewhat controversial. The cyclic aspect of convective heat loss, and radiation from incandescent soot particles, also deserve attention. The temperatures resulting from insulating the cylinder of the LHR diesel require advancements in lubrication. The engine designer must learn to deal with the probabilistic nature of failure in brittle ceramics needed for engine construction. Whether ceramic monoliths or coatings are more appropriate for cylinder insulation remains unsettled. These challenges confronting the LHR diesel are reviewed.
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Rozprawy doktorskie na temat "Low temperature heat engine"

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Hoegel, Benedikt. "Thermodynamics-based design of stirling engines for low-temperature heat sources". Thesis, University of Canterbury. Mechanical Engineering, 2014. http://hdl.handle.net/10092/9344.

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Large amounts of energy from heat sources such as waste-eat and geothermal energy are available worldwide but their potential for useful power-generation is largely untapped. This is because they are relatively low temperature difference (LTD) sources, in the range from 100 to 200 °C, and it is thermodynamically diffcult, for theoretical and practical reasons, to extract useful work at these temperatures. This work explores the suitability of a Stirling engine (SE) to exploit these heat sources. Elsewhere much work has been done to optimise Stirling engines for high temperature heat sources, but little is known about suitable engine layouts, and their optimal design and operational aspects at lower temperature differences. With the reduced temperature difference, changes from conventional engine designs become necessary and robust solutions for this novel application have to be identified. This has been achieved in four major steps: identification of a suitable engine type; thermodynamic optimisation of operating and engine parameters; optimisation of mechanical efficiency; and the development of conceptual designs for the engine and its components informed by the preceding analysis. For the optimisation of engine and operating parameters a model was set up in the commercial Stirling software package, Sage, which also has been validated in this thesis; suitable parameter combinations have been identified. This work makes key contributions in several areas. This first is the identification of methods for better simulating the thermodynamic behaviour of these engines. At low temperature differences the performance of Stirling engines is very sensitive to losses by fluid friction (and thus frequency), adiabatic temperature rise during compression, and the heat transfer from and to the surroundings. Consequently the usual isothermal analytical approaches produce results that can be misleading. It is necessary to use a non-isothermal approach, and the work shows how this may be achieved. A second contribution is the identification of the important design variables and their causal effects on system performance. The primary design variable is engine layout. For an engine having inherently low efficiency due to the low temperature difference it is important to choose the engine layout that provides the highest power density possible in order to minimise engine size and to save costs. From this analysis the double-acting alpha-type configuration has been identified as being the most suitable, as opposed to the beta or gamma configurations. An-other key design variable is working fluid, and the results identify helium and hydrogen as suitable, and air and nitrogen as unsuitable. Frequency and phase angle are other design variables, and the work identifies favourable values. A sensitivity analysis identifies the phase angle, regenerator porosity, and temperature levels as the most sensitive parameters for power and efficiency. It has also been shown that the compression work in low-temperature difference Stirling engines is of similar magnitude as the expansion work. By compounding suitable working spaces on one piston the net forces on the piston rod can be reduced significantly. In double-acting alpha-engines this can be achieved by choosing the Siemens as opposed to the Franchot arrangement. As a result friction and piston seal leakage which are two important loss mechanisms are reduced significantly and longevity and mechanical efficiency is enhanced. Design implications are identified for various components, including pistons, seals, heat exchangers, regenerator, power extraction, and crankcase. The peculiarities of the heat source are also taken into account in these design recommendations. A third key contribution is the extraction of novel insights from the modelling process. For the heat exchangers it has been shown that the hot and cold heat exchangers can be identical in their design without any negative impact on performance for the low-temperature difference situation. In comparison the high temperature applications invariably require different materials and designs for the two heat exchangers. Also, frequency and phase angle are found to be quite different (lower frequency and higher phase angle) from the optimum parameters found in high temperature engines. Contrary to common belief the role of dead volume has been found to play a crucial and not necessary detrimental role at low temperature differentials. Taken together, the work is positioned at the intersection of thermodynamic analysis and engineering design, for the challenging area of Stirling engines at low temperature differences. The work extracts thermodynamic insights and extends these into design implications. Together these help create a robust theoretical and design foundation for further research and development in the important area of energy recovery.
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Lloyd, Caleb Charles. "A Low Temperature Differential Stirling Engine for Power Generation". Thesis, University of Canterbury. Department of Electrical and Computer Engineering, 2009. http://hdl.handle.net/10092/2916.

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There are many sources of free energy available in the form of heat that is often simply wasted for want of an effective way to convert it into useful energy such as electricity. The aim of this research project is to design and build a low temperature differential Stirling engine capable of generating electric power from heat sources such as waste hot water or geothermal springs. The engine that has been developed is a research prototype model of a new type of design featuring a rotating displacer which is actuated by a pair of stepper motors. The rotating displacer design enables the use of readily available and comparatively cheap and robust steam pipe as the housing for the engine, and it also avoids problems associated with sealing and heat exchange that would be present in a large engine of a more traditional configuration. Owing to the fact that this engine is a research prototype, it has the ability to have some of its critical operating parameters such as phase angle and stroke length adjusted to investigate the effects on performance. When the next phase of development takes place most of these parameters will be fixed at the optimum values which will make manufacture cheaper and easier. Unfortunately, construction of the prototype engine has not been completed at the time of writing so no power producing results have been achieved; however thorough results are presented on the operation of the control system for the stepper motors which actuate the displacer. Additionally, after a thorough history and background of Stirling engines was researched, the understanding gained of how these engines work has enabled a design process to take place which has hopefully led to a successful design. Analysis of various aspects of the engine have been carried out and results look promising for the engine to produce around 500 Watts of electrical power output whilst running on hot water up to around 90°C.
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Kalua, Tisaye Bertram. "Analysis of factors affecting performance of a low-temperature Organic Rankine Cycle heat engine". Thesis, Nelson Mandela Metropolitan University, 2017. http://hdl.handle.net/10948/17844.

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Organic Rankine Cycle (ORC) heat engines convert low-grade heat to other forms of energy such as electrical and mechanical energy. They achieve this by vaporizing and expanding the organic fluid at high pressure, turning the turbine which can be employed to run an alternator or any other mechanism as desired. Conventional Rankine Cycles operate with steam at temperatures above 400 ℃. The broad aspect of the research focussed on the generation of electricity to cater for household needs. Solar energy would be used to heat air which would in turn heat rocks in an insulated vessel. This would act as an energy storage in form of heat from which a heat transfer fluid would collect heat to supply the ORC heat engine for the generation of electricity. The objective of the research was to optimize power output of the ORC heat engine operating at temperatures between 25℃ at the condenser and 90 to 150℃ at the heat source. This was achieved by analysis of thermal energy, mechanical power, electrical power and physical parameters in connection with flow rate of working fluid and heat transfer fluids.
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Bryson, Matthew John, i mbryson@bigpond net au. "The conversion of low grade heat into electricity using the Thermosyphon Rankine Engine and Trilateral Flash Cycle". RMIT University. Aerospace, Mechanical and Manufacturing Engineering, 2007. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080130.162927.

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Low grade heat (LGH) sources, here defined as below 80ºC, are one group of abundant energy sources that are under-utilised in the production of electricity. Industrial waste heat provides a convenient source of concentrated LGH, while solar ponds and geothermal resources are examples of sustainable sources of this energy. For a number of years RMIT has had two ongoing, parallel heat engine research projects aimed at the conversion of LGH into electricity. The Thermosyphon Rankine Engine (TSR) is a heat engine that uses water under considerable vacuum. The other research stream uses a hydrocarbon based working fluid in a heat engine employing the Trilateral Flash Cycle (TFC). The TSR Mk V was designed and built as a low cost heat engine for the conversion of LGH into electricity. Its main design advantages are its cost and the employment of only one moving part. Using the data gained from the experimental rig, deviations from the expected results (those derived theoretically) were explored to gain insight for further development. The results from the TSR rig were well below those expected from the design specifications. Although the experimental apparatus was able to process the required heat energy, the efficiency of conversion fell well below the expected 3% and was approximately 0.2%. The inefficiency was explained by a number of contributing factors, the major being form drag upon the rotor that contributed around 2/3 of the losses. Although this was the major cause of the power loss, other factors such as the interference with the rotor by the condensate on its return path contributed to the overall poor performance of the TSR Mk V. The RMIT TFC project came about from exploration of the available academic literature on the subject of LGH conversion. Early work by researchers into applying Carnot's theory to finite heat sources led them to explore the merits of sensible heat transfer combined with a cycle that passes a liquid (instead of a gas) though an expander. The results showed that it was theoretically possible to extract and convert more energy from a heat source of this type using this method than using any other alternative. This previous research was targeted at heat sources above 80ºC and so exploration of the theoretical and empirical results for sources below this temperature was needed. Computer models and an experimental rig using isopentane (with a 28ºC boiling point at atmospheric pressure) were produced to assess the outcomes of employing low temperature heat sources using a TFC. The experimental results from the TFC research proved promising with the efficiency of conversion ranging from 0.8% to 2.4%. Although s uch figures seem poor in isolation, it should be noted that the 2.4% efficiency represents an achievement of 47% of the theoretical ideal conversion efficiency in a rig that uses mainly off-the-shelf components. It also confirms that the TFC shows promise when applied to heat sources less than 80ºC.
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Andruskiewicz, Peter Paul. "ANALYTICAL AND EXPERIMENTAL INVESTIGATION OF TEMPERATURE-SWING INSULATION ON ENGINE PERFORMANCE". Doctoral thesis, Universitat Politècnica de València, 2017. http://hdl.handle.net/10251/90467.

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In-cylinder thermal barrier materials have been thoroughly investigated for their potential improvements in thermal efficiency in reciprocating internal combustion engines. These materials show improvements both directly in indicated work and indirectly through reduced demand on the cooling system. Many experimental and analytical sources have shown reductions in heat losses to the combustion chamber walls, but converting the additional thermal energy to indicated work has proven more difficult. Gains in indicated work over the expansion stroke could be made, but these were negated by increased compression work and reduced volumetric efficiency due to charge heating. Typically, the only improvements in brake work would come from the pumping loop in turbocharged engines, or from additional exhaust energy extraction through turbine-compounding devices. The concept of inter-cycle wall-temperature-swing holds promise to reap the benefits of insulation during combustion and expansion, while not suffering the penalties incurred with hotter walls during intake and compression. The combination of low volumetric heat capacity and low thermal conductivity would allow the combustion chamber surface temperature to quickly respond to the gas temperature throughout combustion. Surface temperatures are capable of rising in response to the spike in heat flux, thereby minimizing the temperature difference between the gas and wall early in the expansion stroke when the greatest conversion of thermal energy to mechanical work is possible. The combination of low heat capacity and thermal conductivity is essential in allowing this temperature increase during combustion, and in enabling the surface to cool during expansion and exhaust to avoid harmfully affecting engine volumetric efficiency during the intake stroke and minimizing compression work performed on the next stroke. In this thesis, thermal and thermodynamic models are constructed in an attempt to predict the effects of material properties in the walls, and to characterize the effects of heat transfer at different portions of the cycle on indicated work, volumetric efficiency, exhaust energy and gas temperatures of a reciprocating internal combustion engine. The expected impact on combustion knock in spark-ignited engines was also considered, as this combustion mode was the basis for the experimental engine testing performed. Conventional insulating materials were evaluated to benchmark the current state-of-the-art, and to gain experience in the analysis of materials with temperature-swing capability. Unfortunately, the effects of permeable porosity within the conventional coating on heat losses, fuel absorption and compression ratio tended to mask the effects of temperature swing. The individual impact of each of these loss mechanisms on engine performance was analyzed, and the experience helped to further refine the necessary traits of a successful temperature-swing material Finally, from the learnings of this analysis phase, a novel material was created and applied to the piston surface, intake valve faces, and exhaust valve faces. Engine data was taken with these coated components and compared to an un-coated baseline. While some of the test pieces physically survived the testing, analysis of the data suggests that they were not fully sealed and suffered from the same permeability losses that affected the conventional insulation. Further development is necessary to arrive at a robust, effective solution for minimizing heat transfer through wall temperature swing in reciprocating internal combustion engines. The success of temperature-swing thermal barrier materials requires very low thermal conductivity, heat capacity, and appropriate insulation thickness, as well as resilient sealing of any porous volume within the coating to avoid additional heat and fuel energy losses throughout the cycle.
Los materiales aislantes han sido investigados a fondo por sus posibles mejoras en la eficiencia térmica de los motores de combustión interna alternativos. Estas mejoras se ven reflejadas tanto directamente en el trabajo indicado como indirectamente a través de la reducción del sistema de refrigeración del propio motor. Diferentes estudios, tanto experimentales como analíticos, han mostrado la reducción en la transferencia de calor a través de las paredes de la cámara de combustión mediante la utilización de estos materiales. Sin embargo, demostrar la conversión de la energía térmica adicional en trabajo indicado ha resultado más difícil. En ciertos estudios se pudieron obtener mejoras en el trabajo indicado durante la carrera de expansión, pero éstas fueron reducidas debido a un menor rendimiento volumétrico debido al calentamiento de la carga durante el proceso de admisión y un mayor trabajo en la carrera de compresión. Típicamente, las únicas mejoras en el trabajo al freno provendrían de la reducción de pérdidas por bombeo en los motores turboalimentados, o de la extracción de la energía adicional de los gases de escape a través de turbinas. El concepto de los materiales con oscilación de la temperatura durante el ciclo motor intenta aprovechar los beneficios del aislamiento durante los procesos de combustión y expansión, mitigando las perdidas por el incremento de la temperatura de las paredes durante la admisión y la compresión. La combinación de baja capacidad calorífica y baja conductividad térmica permitiría que la temperatura de la superficie de la cámara de combustión respondiera rápidamente a la temperatura del gas durante el proceso de combustión. Las temperaturas de la superficie son capaces de aumentar en respuesta al pico de flujo de calor, minimizando así la diferencia de temperatura entre el gas y la pared en la carrera de expansión cuando es posible la mayor conversión de energía térmica en trabajo mecánico. La combinación de baja capacidad calorífica y conductividad térmica es también esencial para permitir este aumento de temperatura durante la combustión y para permitir que la superficie se enfríe durante la expansión y el escape para no perjudicar así el rendimiento volumétrico del motor durante la carrera de admisión y minimizar el trabajo de compresión realizado en el siguiente ciclo. En esta tesis se han desarrollado modelos térmicos y termodinámicos para predecir los efectos de las propiedades de los materiales en las paredes y caracterizar los efectos de la transferencia de calor en diferentes partes del ciclo sobre el trabajo indicado, el rendimiento volumétrico, la energía en los gases de escape y las temperaturas del gas para un motor de combustión interna alternativo. También se ha evaluado el impacto del uso de estos materiales en el knock en motores de combustión de encendido provocado, ya que los estudios experimentales de esta tesis se realizaron en un motor de estas características. Durante la investigación se evaluaron materiales aislantes convencionales para comprender el estado actual de esta técnica y para adquirir también experiencia en el análisis de materiales aislantes con oscilación de temperatura. Desafortunadamente, los efectos de la permeabilidad a través de la porosidad del material en los recubrimientos convencionales, la absorción de combustible y la relación de compresión tendieron a ocultar los efectos de la oscilación de la temperatura y la reducción de la transferencia de calor a través de las paredes. Así pues, se analizó el impacto individual de cada uno de estos mecanismos y su influencia en el rendimiento del motor para así definir un nuevo material con las características necesarias que mejorasen el aislante con de oscilación de temperatura. Finalmente, a partir de los estudios de esta fase de análisis, se creó un nuevo material y se aplicó a la superficie del pistón y a la supe
Els materials aïllants han estat investigats a fons per les seves possibles millores en l'eficiència tèrmica en el motors de combustió interna alternatius. Aquestes millores es veuen reflectides tant directament en el treball indicat com indirectament a través de la reducció del sistema de refrigeració del propi motor. Diferents estudis, tant experimentals com analítics, han mostrat la reducció en la transferència de calor a través de les parets de la cambra de combustió mitjançant la utilització d'aquests materials. No obstant això, demostrar la conversió de l'energia tèrmica addicional en treball indicat ha resultat més difícil. En certs estudis es van poder obtenir millores en el treball indicat durant la carrera d'expansió, però aquestes van ser reduïdes a causa d'un menor rendiment volumètric causat de l'escalfament de la càrrega durant el procés d'admissió i un major treball en la carrera de compressió. Típicament, les úniques millores en el treball al fre provindrien de la reducció de pèrdues per bombeig en els motors turbo alimentats, o de l'extracció addicional de l'energia dels gasos d'escapament a través de turbines. El concepte dels materials amb oscil·lació de la temperatura durant el cicle motor intenta aprofitar els beneficis de l'aïllament durant els processos de combustió i expansió, mitigant les perdudes per l'increment de la temperatura de les parets durant l'admissió i la compressió. La combinació de baixa capacitat calorífica i baixa conductivitat tèrmica permetria que la temperatura de la superfície de la cambra de combustió respongués ràpidament a la temperatura del gas durant el procés de combustió. Les temperatures de la superfície són capaços d'augmentar en resposta al flux de calor, minimitzant així la diferència de temperatura entre el gas i la paret en la carrera d'expansió quan és possible la major conversió d'energia tèrmica en treball mecànic. La combinació de baixa capacitat calorífica i conductivitat tèrmica és també essencial per permetre aquest augment de temperatura durant la combustió i el refredament de la superfície durant l'expansió i l'escapament per no perjudicar així el rendiment volumètric del motor durant la carrera d'admissió i minimitzar el treball de compressió realitzat en el següent cicle. En aquesta tesi s'han desenvolupat models tèrmics i termodinàmics per predir els efectes de les propietats dels materials en les parets i caracteritzar els efectes de la transferència de calor en diferents parts del cicle sobre el treball indicat, el rendiment volumètric, l'energia en els gasos d'escapament i les temperatures del gas per un motor de combustió interna alternatiu. També s'ha avaluat l'impacte d'aquests materials en el knock en motors de combustió d'encesa provocada, ja que les proves experimentals d'aquesta tesi es van realitzar en un motor d'aquestes característiques. Durant la investigació es van avaluar materials aïllants convencionals per comprendre l'estat actual d'aquesta tècnica i per adquirir també experiència en l'anàlisi de materials aïllants amb oscil·lació de temperatura. Desafortunadament, els efectes de la permeabilitat a través de la porositat del material en el recobriment convencional, l'absorció de combustible i la relació de compressió van tendir a ocultar els efectes de l'oscil·lació de la temperatura i la reducció de la transferència de calor a través de les parets. Així doncs, es va analitzar l'impacte individual de cada un d'aquests mecanismes i la seva influència en el rendiment del motor per així definir un nou material amb les característiques necessàries que milloressin el aïllant d'oscil·lació de temperatura. Finalment, a partir dels estudis d'aquesta fase d'anàlisi, es va crear un nou material i es va aplicar a la superfície del pistó i a la superfície interna de les vàlvules d'admissió i d'escapament. Les dades de motor es van prendre a
Andruskiewicz, PP. (2017). ANALYTICAL AND EXPERIMENTAL INVESTIGATION OF TEMPERATURE-SWING INSULATION ON ENGINE PERFORMANCE [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/90467
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Hegana, Ashenafi B. "Low Temperature Waste Energy Harvesting by Shape Memory Alloy Actuator". University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1461631046.

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Moratal, Martínez Ausiás Alberto. "EXPERIMENTAL ANALYSIS OF THERMAL MANAGEMENT INFLUENCE ON PERFORMANCE AND EMISSIONS IN DIESEL ENGINES AT LOW AMBIENT TEMPERATURE". Doctoral thesis, Universitat Politècnica de València, 2018. http://hdl.handle.net/10251/111950.

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La regulación mundial de emisiones contaminantes en el sector de la automoción está siendo cada día más estricta. La implantación de nuevos procedimientos está presionando la industria hacia la búsqueda de nuevas tecnologías que cumplan los objetivos de reducción de emisiones contaminantes. En el medio plazo se espera que las pruebas de emisiones a baja temperatura ambiente sean obligatorias en el proceso de homologación. La combustión a bajas temperaturas influye de forma importante en la velocidad de la reacción conllevando un aumento de las emisiones y finalmente al apagado de llama. Bajo estas condiciones, se produce un aumento de las emisiones de hidrocarburos (HC) y monóxido de carbono (CO) así como un aumento del consumo de combustible. Además, en condiciones de baja temperatura ambiente las emisiones de óxidos de nitrógeno (NOx) pueden aumentar debido a la desactivación de los sistemas de recirculación de gases de escape. En la presente tesis, se ha analizado el efecto de la baja temperatura ambiente en un motor diesel HSDI. Los ensayos fueron realizados en ciclos de conducción NEDC y WLTC. La influencia directa de las bajas temperaturas en las emisiones se analizó por medio de las medida bruta de contaminantes, aguas arriba de los sistemas de postratamiento. El funcionamiento de los sistemas de postratamiento también fue evaluado a bajas temperaturas mediante la eficiencia de la oxidación catalítica de HC y CO. Los resultados de este estudio mostraron un deterioro de las emisiones y del rendimiento efectivo a bajas temperaturas. El efecto de las bajas temperaturas varió dependiendo de condiciones de carga. El ciclo NEDC se consolida como el peor escenario de conducción, para la realización de pruebas a baja temperatura, con un incremento del 270% en HC, 250% en NOx, 125% en CO y 20% en consumo específico. El mayor grado de carga junto con el carácter más transitorio del ciclo WLTC mostraron un efecto menor de las bajas temperaturas ambiente con un aumento del 150% en HC y 250% en NOx. A diferencia del ciclo NEDC, las emisiones de CO se redujeron en un 20% y no se detectó un aumento del consumo de combustible. Además del aumento de la formación de contaminates, el análisis del catalizador de oxidación mostró una reducción de la eficiencia en ambos ciclos de conducción NEDC y WLTC. El presente trabajo tiene por objetivo comparar dos sistemas de gestión térmica para la mejora del funcionamiento de MCIA a bajas temperaturas. El primer sistema estaba basado en la gestión del flujo de refrigerante para evitar subenfriamiento en condiciones de funcionamiento en frío. Por un lado, se propusieron estrategias de bajo y nulo flujo en el circuito de refrigerante motor. Por otro lado, se realizaron ensayos con 0 flujo en el circuito de refrigerante del WCAC para evitar el subenfriamiento del aire de admisión durante puntos de baja carga en condiciones de funcionamiento en frío. El otro sistema incluía la recuperación de energía térmica del escape (EGHR). El refrigerante del WCAC se empleó como fluido de recuperación conectándose con un intercambiador de escape. La primera parte de los resultados de la gestión térmica están centrados en el análisis individual de los distintos sistemas de gestión. En las conclusiones se comparan todos los sistemas propuestas explicando las diferencias entre ellos. Mediante el uso del EGHR las emisiones de HC fueron reducidas, durante los puntos de baja carga, en comparación con el resto de estrategias térmicas planteadas. El análisis energético del EGHR se centró en la eficiencia y en el estudio la recuperación por cambio de fase. El papel que la entalpia de cambio de fase juega en la recuperación de calor residual fue estudiado por medio de la medición de concentración de vapor de agua en el gas de escape en la entrada y salida del intercambiador del EGHR. La condensación del vapor de agua de escape representó el 25% de toda la
Automotive world-wide pollutant emissions regulations are getting more stringent every day. New testing procedures are pushing the automotive industry towards researching new technologies to accomplish the emissions targets. In the mid-term future is expected that low ambient temperature emissions testing will become mandatory for any engine model type approval. Low ignition temperature greatly influences on combustion rate leading to emissions increase and eventually to misfiring events. In these conditions, high emissions of unburned hydrocarbon (HC) and carbon monoxide (CO) are released along with fuel consumption penalties. In addition, nitrogen oxides (NOx) emissions may rise under cold conditions owing to the disabling of Exhaust Gas Recirculation (EGR) systems at cold conditions. In this thesis the effect of low ambient temperature in a High Speed Direct Injection (HSDI) Light Duty (LD) engine is analysed. Tests were performed in New European Driving Cycles (NEDC) and Worldwide harmonized Light vehicles Tests (WLTC). Direct influence of low temperature on engine emissions was addressed by engine out pollutants sampling. The effect on aftertreatment systems was also evaluated by the CO and HC oxidation efficiency. The results of this survey indicated a general detriment of pollutant emissions and brake thermal efficiency at low ambient temperatures. The effect of low temperature varied depending on the engine load test conditions. NEDC comes up as the worst scenario for low temperature testing with an increase of 270% in HC, 250% in NOx, 125% in CO and 20% in Brake Specific Fuel Consumption (BSFC). Running at higher engine loads and transient conditions, as it's performed in WLTC tests, showed a lower effect of ambient temperature with an increase of 150% in HC and 250% in NOx. In contrast to NEDC, CO emissions were reduced in 20% and no engine efficiency penalty was spotted. In addition to the pollutant emission formation increase, the aftertreatment analysis showed a significant reduction of the Diesel Oxidative Catalyst (DOC) efficiency in both NEDC and WLTC. This work is aimed to analyse and compare two different thermal management approaches for engine enhancement running at low ambient temperature. The first approach relied on coolant management aimed to avoid overcooling when running at cold conditions. On one hand, low flow and 0 flow engine coolant strategies were performed while Water Charge Air Cooled (WCAC) coolant is recirculated. On the other hand, WCAC 0 flow was applied for avoiding overcooling at low ambient temperatures. The other layout was based on an exhaust gas heat recovery system (EGHR). WCAC coolant was directed to an exhaust tail pipe heat exchanger for waste heat recovery. Recovered heat was released in the WCAC for speeding up the intake air temperature increase. The first part of the thermal management results is focused on the analysis by thermal layout. Comparison of both thermal management is discussed in the conclusions section of that chapter. By enabling an EGHR system, HC emissions were reduced during low load driving phases in comparison with the other of layouts. EGHR energy analysis was also conducted, focusing on energy efficiency and phase change recovery analysis. The role that latent enthalpy plays on waste heat recovery was addressed by measuring the water vapour concentration in the exhaust stream at both EGHR heat exchanger inlet and outlet. Water vapour condensation represented the 25% of the total recovered energy.
La regulació mundial d'emissions contaminants en el sector de l'automoció està sent cada vegada més estricta. La implantació de nous procediments està pressionant la indústria cap a la cerca de noves tecnologies que complisquen els objectius de reducció d'emissions contaminants. En el mig termini s'espera que les proves d'emissions a baixa temperatura ambient siguen obligatòries en el procés d'homologació. La combustió a baixes temperatures influeix de forma important en la velocitat de la reacció comportant un augment de les emissions i finalment a l'apagat de flama. Sota aquestes condicions, es produeix un augment de les emissions d'hidrocarburs (HC) i monòxid de carboni (CO) així com un augment del consum de combustible. A més, en condicions de baixa temperatura ambiente les emissions d'òxids de nitrogen (NOx) poden augmentar a causa de la desactivació dels sistemes de recirculació de gasos d'escapament. En la present tesi, s'ha analitzat l'efecte de la baixa temperatura ambiente en un motor dièsel HSDI. Els assajos van ser realitzats en cicles de conducció NEDC i WLTC. La influència directa de les baixes temperatures en les emissions es va analitzar per mitjà de la mesura bruta de contaminants, aigües a dalt dels sistemes de postractament. El funcionament dels sistemes de postractament també va ser avaluat a baixes temperatures mitjançant l'eficiència de la oxidació catalítica de HC i CO. Els resultats d'aquest estudi van mostrar una deterioració de les emissions i del rendiment efectiu a baixes temperatures. L'efecte de les baixes temperatures variava depenent de les condicions de càrrega. El cicle NEDC es consolida com el pitjor escenari de conducció, per a la realització de proves a baixa temperatura, amb un increment del 270% en HC, 250% en NOx, 125% en CO i 20% en consum específic. El major grau de càrrega juntament amb el caràcter més transitori del cicle WLTC van mostrar un efecte menor de les baixes temperatures ambient amb un augment del 150% en HC i 250% en NOx. A diferència del cicle NEDC, les emissions de CO es van reduir en un 20% i no es va detectar un augment del consum de combustible. A més de l'augment de la formació de contaminants, l'anàlisi del catalitzador d' oxidació va mostrar una reducció de l'eficiència en tots dos cicles de conducció NEDC i WLTC. El present treball té per objectiu comparar dos sistemes de gestió tèrmica per a la millora del funcionament dels MCIA a baixes temperatures. El primer sistema estava basat en la gestió del flux de refrigerant per a evitar subrefredament en condicions de funcionament en fred. D'una banda, es van proposar estratègies de baix i nul flux en el circuit de refrigerant motor. D'altra banda, es van realitzar assajos amb 0 flux en el circuit de refrigerant del WCAC per a evitar el subrefredament de l'aire d'admissió durant punts de baixa càrrega en condicions de funcionament en fred. L'altre sistema incloïa la recuperació d'energia tèrmica de l'escapament (EGHR). El refrigerant del WCAC es va emprar com fluït de recuperació connectant-se amb un bescanviador d'escapament. La primera part dels resultats de la gestió tèrmica estan centrats en l'anàlisi individual dels diferents sistemes de gestió. En les conclusions es comparen tots els sistemes proposats explicant les diferències entre ells. Mitjançant l'ús del EGHR les emissions de HC van ser reduïdes, durant els punts de baixa càrrega, en comparació de la resta d'estratègies tèrmiques plantejades. L'anàlisi energètic del EGHR es va centrar en l'eficiència i en l'estudi de la recuperació per canvi de fase. El paper que l'entalpia de canvi de fase juga en la recuperació de calor residual va ser estudiat per mitjà del mesurament de concentració de vapor d'aigua en el gas d'escapament en l'entrada i eixida del bescanviador del EGHR. La condensació del vapor d'aigua de l'escapament va representar el 25% de tota l'energia recuperada.
Moratal Martínez, AA. (2018). EXPERIMENTAL ANALYSIS OF THERMAL MANAGEMENT INFLUENCE ON PERFORMANCE AND EMISSIONS IN DIESEL ENGINES AT LOW AMBIENT TEMPERATURE [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/111950
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Pfaff, Michael. "Power Production from Low Temperature Heat Sources". Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for energi- og prosessteknikk, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18330.

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SummaryThis Master Thesis is a conclusion on work done as part of the Resource Optimizationand recovery in the Materials industry project (Roma). This project is involved in thedevelopment of a new technology for power production from low temperature heat sourcesfor off gases from aluminum production cells. The technology is based on an transcriticalRankine cycle with CO2 as a working fluid, as the work recovery circuit. The center ofthe test facility is the expander, a prototype provided by Obrist Engineering . 81 testswere perfomed to investigate the behavoir of the expander cycle. Effect of three mainparameters were investigated:• Effect CO2 massflow rate• Effect of heat source temperature• Effect of CO2 condensation pressureFor each parameter combination, the high pressure side of the expander cycle was variedin order to find the maximum power output.This study clearly showed limitation of the turbine which cannot maintain large pressuredifference probably due to large internal leakages. As a result, turbine outlet is highlysuperheated. This superheat is lost energy for the power cycle, and is simply dumpedinto the heat sink. One possible improvement would be to include a recuperator thatrecovers superheat after the pump.The results also indicate that the fan of the air loop is too small: increasing the CO2 flowrate to limit superheat at turbine outlet leads to turbine inlet temperature reduction.Last, for large CO2 mass flow rate (3.5 kgmin) which is required for proper operation ofthe turbine, the power generated is too large for the generator installed on the loop. Itstemperature reached 120 °C for some conditions. A new solution should be seeked.Based on experimental results, a mode of the power cycle was implemented in Pro/IIand simulations were run in order to find an improved design. The main goal is to beable to run the cycle at high CO2 mass flow rate: 3.5 kgmin. It was found that the airloop fan should be able to deliver up to 1 260 m3h . The new generator or braking systemshould be able to absorb up to 297 W.
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Midtsjø, Alexander. "Power Production from Low Temperature Heat Sources". Thesis, Norwegian University of Science and Technology, Department of Energy and Process Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9902.

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As part of the energy recovery part of the ROMA (Resource Optimization and recovery in the Materials industry) project, a laboratory prototype power production system is being built and completed in 2009. The laboratory prototype is based on a new technology for power production from low to medium temperature heat sources (the off gas from electrolysis cells in the aluminum industry) where CO2 is used as a working medium in a trans-critical Rankine cycle. The laboratory rig consists of the power cycle with a prototype expander as the core unit, an air loop to provide the heat, and an ethylene glycol loop to provide condensation of the working fluid in the power cycle. As a preparation to the assembling and instrumentation of the prototype rig, a simulation and an uncertainty analysis were conducted for the prototype rig in the autumn of 2008. This report focuses on the continuation of that work by an experimental investigation of the individual loops and the components of the prototype rig. The emphasis of this investigation has been put on the air loop and the expander unit of the power cycle. This is basically because these are of great importance to the performance of the power production prototype rig. The air loop was thoroughly tested, and from the investigations it was discovered that there was an unfavorable temperature distribution of the air going into the air-to-CO2 heat exchanger. This is the heat exchanger where heat is provided to the power cycle. The source for this temperature maldistribution was identified, and solutions were investigated to improve on the problem without results. The reduced performance of the air loop was incorporated in a new simulation of the power cycle in order to quantify the consequences for the optimization of the power cycle. The simulation was carried out for warm air temperature of 80 °C. The new calculations showed a reduction in maximum net work output of 27 % compared to the original simulation. The optimal conditions for the power cycle were also changed as a consequence of the reduced air loop performance. The investigation of the expander unit revealed that the expander isentropic efficiency was a strong function of the pressure difference across the expander, and a weak function of the expander inlet pressure. It also revealed that overall the isentropic efficiency was much less than the value of 80 % which was used in the original simulation. A new simulation of the power cycle was carried out where the expander isentropic efficiency was incorporated as a function of the pressure difference across the expander. This function was based on the data from the expander testing. The simulation showed a reduction in maximum net work output from 225 W to about 60 W, for warm air temperature of 80 °C. The new expander characteristics also affected the optimization of the power cycle. The simulation results and the results from the prototype investigation will be important in the optimization and control procedures of the assembled prototype power production system.

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Farrokhpanah, Sonia. "Design of heat integrated low temperature distillation systems". Thesis, University of Manchester, 2009. http://www.manchester.ac.uk/escholar/uk-ac-man-scw:228854.

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This work addresses the challenges in design of heat integrated low-temperature separation processes. A novel, systematic and robust methodology is developed, which contributes to the design practice of heat-integrated separation sequence and the refrigeration system in the context of low-temperature separation processes. Moreover, the methodology exploits the interactions between the separation and refrigeration systems systematically in an integrated design context. The synthesis and optimisation of heat-integrated separation processes is complex due to the large number of design options. In this thesis, task representation is applied to the separation system to accommodate both simple and complex distillation columns. The stream conditioning processes are simulated and their associated costs are included in the overall cost of the process. Important design variables in separation systems, such as the separation sequence, type and operating conditions of the separation units (e.g. the operating pressure, feed quality and condenser type) are optimised. Various refrigeration provision strategies, such as expansion of a process stream, pure and mixed multistage refrigeration systems and cascades of multistage refrigeration cycles, are considered in the present work. A novel approach based on refrigeration system database is proposed, which overcomes the complexities and challenges of synthesis and optimisation of refrigeration systems in the context of low-temperature separation processes. The methodology optimises the key design variables in the refrigeration system, including the refrigerant composition, the number of compression stages, the refrigeration and rejection temperature levels, cascading strategy and the partition temperature in multistage cascaded refrigeration systems. The present approach has selected a matrix based approach for assessing the heat integration potentials of separation and refrigeration systems in the screening procedure. Non-isothermal streams are not considered isothermal and stream splitting and heat exchangers in series are taken into account. Moreover, heat integration of reboiler and condenser of a distillation column through an open loop heat pump system can be considered in this work. This work combines an enhanced simulated annealing algorithm with MILP optimisation method and develops a framework for simultaneously optimising different degrees of freedom in the heat integrated separation and refrigeration processes. Case studies extend the approach to the design of heat integrated separation sequences in above ambient temperature processes. The robustness of the developed framework is further demonstrated when it is utilised to design the LNG and ethylene plant fractionation trains.
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Książki na temat "Low temperature heat engine"

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Cryogenic regenerative heat exchangers. New York: Plenum Press, 1997.

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Toal, Bernard Robert Hugh. The application of heat pumps to low temperature drying. [S.l: The Author], 1985.

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Coccia, Gianluca, Giovanni Di Nicola i Alejandro Hidalgo. Parabolic Trough Collector Prototypes for Low-Temperature Process Heat. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-27084-5.

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Cryogenic heat transfer. Philadelphia, PA: Taylor and Francis, 1999.

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Rhodes, RB, red. Low Temperature Lubricant Rheology Measurement and Relevance to Engine Operation. 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959: ASTM International, 1992. http://dx.doi.org/10.1520/stp1143-eb.

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O'Rourke, Gareth. The cryogenic heat treatment of tool steels. Dublin: University College Dublin, 1998.

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Verkin, B. I. Teploobmen pri kipenii kriogennykh zhidkosteĭ. Kiev: Nauk. dumka, 1987.

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Meeting, Materials Research Society. High temperature radiator materials for applications in the low earth orbital environment. Cleveland, Ohio: [National Aeronautics and Space Administration], Lewis Research Center, 1987.

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Yen, Yin-Chao. Sensible heat flux measurements near a cold surface. [Hanover, N.H.]: U.S. Army Corps of Engineers, Cold Regions Research & Engineering Laboratory, 1995.

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Yen, Yin-Chao. On the temperature distribution near a cold surface. [Hanover, N.H.]: U.S. Army Corps of Engineers, Cold Regions Research & Engineering Laboratory, 1993.

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Części książek na temat "Low temperature heat engine"

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Rijpkema, Jelmer, Karin Munch i Sven B. Andersson. "Combining Low- and High-Temperature Heat Sources in a Heavy Duty Diesel Engine for Maximum Waste Heat Recovery Using Rankine and Flash Cycles". W Energy and Thermal Management, Air-Conditioning, and Waste Heat Utilization, 154–71. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-030-00819-2_12.

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Thring, R. H. "Low Heat Rejection Diesel Engines". W Automotive Engine Alternatives, 167–82. Boston, MA: Springer US, 1987. http://dx.doi.org/10.1007/978-1-4757-9348-2_7.

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Collings, E. W. "Low-Temperature Specific Heat". W Applied Superconductivity, Metallurgy, and Physics of Titanium Alloys, 307–33. Boston, MA: Springer US, 1986. http://dx.doi.org/10.1007/978-1-4613-2095-1_8.

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Warnatz, Jürgen, Ulrich Maas i Robert W. Dibble. "Low Temperature Oxidation, Engine Knock". W Combustion, 227–36. Berlin, Heidelberg: Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/978-3-642-98027-5_16.

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Warnatz, Jürgen, Ulrich Maas i Robert W. Dibble. "Low Temperature Oxidation, Engine Knock". W Combustion, 227–36. Berlin, Heidelberg: Springer Berlin Heidelberg, 2001. http://dx.doi.org/10.1007/978-3-662-04508-4_16.

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Albin Rajasingham, Thivaharan. "Low-Temperature Combustion Engine Control". W Nonlinear Model Predictive Control of Combustion Engines, 195–212. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-68010-7_8.

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Denlinger, David L., Karl H. Joplin, Cheng-Ping Chen i Richard E. Lee. "Cold Shock and Heat Shock". W Insects at Low Temperature, 131–48. Boston, MA: Springer US, 1991. http://dx.doi.org/10.1007/978-1-4757-0190-6_6.

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Vasiliev, L. L., D. A. Mishkinis, A. A. Antukh, A. G. Kulakov i L. L. Vasiliev. "Multisalt-Carbon Portable Resorption Heat Pump". W Low Temperature and Cryogenic Refrigeration, 387–400. Dordrecht: Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-010-0099-4_22.

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Vasiliev, L. L., i A. G. Kulakov. "Heat Pipe Applications in Sorption Refrigerators". W Low Temperature and Cryogenic Refrigeration, 401–14. Dordrecht: Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-010-0099-4_23.

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Fisher, R. A., S. E. Lacy, C. Marcenat, J. A. Olsen, N. E. Phillips, Z. Fisk, A. L. Giorgi, J. L. Smith i G. R. Stewart. "Low-Temperature Specific Heat of UBe13". W Theoretical and Experimental Aspects of Valence Fluctuations and Heavy Fermions, 345–48. Boston, MA: Springer US, 1987. http://dx.doi.org/10.1007/978-1-4613-0947-5_40.

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Streszczenia konferencji na temat "Low temperature heat engine"

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Kumar, Raj, Ming Zheng, Usman Asad i Graham T. Reader. "Heat Release Based Adaptive Control to Improve Low Temperature Diesel Engine Combustion". W SAE World Congress & Exhibition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2007. http://dx.doi.org/10.4271/2007-01-0771.

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Knight, Bryan M., Joshua A. Bittle i Timothy J. Jacobs. "Efficiency Considerations of Later-Phased Low Temperature Diesel Combustion". W ASME 2010 Internal Combustion Engine Division Fall Technical Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/icef2010-35070.

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Low temperature diesel combustion offers an opportunity to simultaneously and substantially reduce exhaust nitrogen oxides and particulate matter emissions. One issue that remains an area of investigation is the improvement of engine efficiency (i.e., specific fuel consumption) for the novel mode of combustion. The objective of this article is to assess the several parameters (i.e., friction, pumping work, combustion phasing, heat transfer rate, and combustion efficiency) that affect the brake fuel conversion efficiencies of a medium-duty diesel engine as its combustion mode is transitioned from conventional to low temperature. The analysis reveals that, in this study’s development of low temperature combustion, late combustion phasing is the primary factor causing a decrease in brake fuel conversion efficiency. To enable low temperature combustion, combustion is retarded to a point where peak rate of heat release occurs at around 24° after top dead center. Such late combustion misses the opportunity to utilize the full expansion stroke of the piston. Although exhaust hydrocarbon and carbon monoxide concentrations increase as a result of the later-phased low temperature combustion mode, combustion efficiency only drops to around 90%. This decrease in combustion efficiency accounts for only about 18.7% of the corresponding decrease in brake fuel conversion efficiency (the balance decrease being caused by the later-phased combustion). Other factors that typically deteriorate brake fuel conversion efficiency (i.e., pumping work, friction, and rate of heat transfer) are all decreased with this study’s development of low temperature combustion. It is important to note that other implementations of low temperature combustion (e.g., advanced timing low temperature combustion) may not necessarily realize the same reductions in brake fuel conversion efficiency, or reductions may not necessarily be caused by the same dominant factors that are observed in this study’s later-phased low temperature combustion mode.
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Shibata, Gen, Koji Oyama, Tomonori Urushihara i Tsuyoshi Nakano. "Correlation of Low Temperature Heat Release With Fuel Composition and HCCI Engine Combustion". W SAE 2005 World Congress & Exhibition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2005. http://dx.doi.org/10.4271/2005-01-0138.

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Qiu, Lu, i Rolf D. Reitz. "Investigating Fuel Condensation Processes in Low Temperature Combustion Engines". W ASME 2014 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/icef2014-5458.

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Condensation of gaseous fuel is investigated in a low temperature combustion engine fueled with double direct-injected diesel and premixed gasoline at two load conditions. Possible condensation is examined by considering real gas effects with the Peng-Robinson equation of state and assuming thermodynamic equilibrium of the two fuels. The simulations show that three representative condensation events are observed. The first two condensations are found in the spray some time after the two direct injections, when the evaporative cooling reduces the local temperature until phase separation occurs. The third condensation event occurs during the late stages of the expansion stroke, during which the continuous expansion sends the local fluid into the two-phase region again. Condensation was not found to greatly affect global parameters, such as the average cylinder pressure and temperature mainly because, before the main combustion event, the condensed phase was converted back to the vapor phase due to compression and/or first stage heat release. However, condensed fuel is shown to affect the emission predictions, including engine-out particulate matter and unburned hydrocarbons.
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Ramachandran, Siddharth, Naveen Kumar i Mallina Venkata Timmaraju. "Parametric study of a low-temperature differential Stirling engine for low-grade thermal energy recovery". W Proceedings of the 25th National and 3rd International ISHMT-ASTFE Heat and Mass Transfer Conference (IHMTC-2019). Connecticut: Begellhouse, 2019. http://dx.doi.org/10.1615/ihmtc-2019.330.

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Sutor, Paul, Ernest E. Schwarz i Harold Pangilinan. "Major Advances in Tribology for Low Heat Rejection Engines: A Ten-Year Overview". W World Tribology Congress III. ASMEDC, 2005. http://dx.doi.org/10.1115/wtc2005-63742.

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In the last decade, Surfaces Research and the U.S. Army have made very significant advances in tribology for high-power-density, low-heat-rejection (LHR) diesel engines. High-temperature tribology issues, which had been major technological hurdles for LHR engine technology, have now been solved. We have developed totally new and economical Group V-based lubricants and self-lubricating coatings in our laboratories. These new lubricants enable reliable, long-term operation of diesel engines with oil sump and engine coolant more than 38°C (100°F) higher than conventional operating temperatures. Over 1300 hours of engine testing have provided detailed data on lubricant and engine component performance at high-temperature, high-BMEP LHR engine conditions.
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Broekaert, Stijn, Michel De Paepe i Sebastian Verhelst. "A Heat Transfer Model for Low Temperature Combustion Engines". W International Powertrains, Fuels & Lubricants Meeting. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2018. http://dx.doi.org/10.4271/2018-01-1662.

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Speer, Connor, David Miller, Calynn Stumpf, Jason Michaud i David Nobes. "Modification of an ST05G-CNC Stirling Engine to Use a Low Temperature Heat Source". W 15th International Energy Conversion Engineering Conference. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2017. http://dx.doi.org/10.2514/6.2017-4793.

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Aniello, Andrea, Lorenzo Bartolucci, Stefano Cordiner, Vincenzo Mulone, Sundar R. Krishnan i Kalyan K. Srinivasan. "CFD Analysis of Diesel-Methane Dual Fuel Low Temperature Combustion at Low Load and High Methane Substitution". W ASME 2018 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/icef2018-9649.

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Over the last few decades, emissions regulations for internal combustion engines have become increasingly restrictive, pushing researchers around the world to exploit innovative propulsion solutions. Among them, the dual fuel low temperature combustion (LTC) strategy has proven capable of reducing fuel consumption and while meeting emissions regulations for oxides of nitrogen (NOx) and particulate matter (PM) without problematic aftertreatment systems. However, further investigations are still needed to reduce engine-out hydrocarbon (HC) and carbon monoxide (CO) emissions as well as to extend the operational range and to further improve the performance and efficiency of dual-fuel engines. In this scenario, the present study focuses on numerical simulation of fumigated methane-diesel dual fuel LTC in a single-cylinder research engine (SCRE) operating at low load and high methane percent energy substitution (PES). Results are validated against experimental cylinder pressure and apparent heat release rate (AHRR) data. A 3D full-cylinder RANS simulation is used to thoroughly understand the influence of the start of injection (SOI) of diesel fuel on the overall combustion behavior, clarifying the causes of AHRR transition from two-stage AHRR at late SOIs to single-stage AHRR at early SOIs, low temperature heat release (LTHR) behavior, as well as high HC production. The numerical campaign shows that it is crucial to reliably represent the interaction between the diesel spray and the in-cylinder charge to match both local and overall methane energy fraction, which in turn, ensures a proper representation of the whole combustion. To that aim, even a slight deviation (∼3%) of the trapped mass or of the thermodynamic conditions would compromise the numerical accuracy, highlighting the importance of properly capturing all the phenomena occurring during the engine cycle. The comparison between numerical and experimental AHRR curves shows the capability of the numerical framework proposed to correctly represent the dual-fuel combustion process, including low temperature heat release (LTHR) and the transition from two-stage to single stage AHRR with advancing SOI. The numerical simulations allow for quantitative evaluation of the residence time of vapor-phase diesel fuel inside the combustion chamber and at the same time tracking the evolution of local diesel mass fraction during ignition delay — showing their influence on the LTHR phenomena. Oxidation regions of diesel and ignition points of methane are also displayed for each case, clarifying the reasons for the observed differences in combustion evolution at different SOIs.
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Tamilporai, P., S. Chandrasekaran, N. Baluswamy i J. Jancirani. "Simulation and Analysis of Combustion and Heat Transfer in Low Heat Rejection Diesel Engine Using Two Zone Combustion Model and Different Heat Transfer Models". W ASME 2002 Internal Combustion Engine Division Fall Technical Conference. ASMEDC, 2002. http://dx.doi.org/10.1115/icef2002-495.

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The quest for increasing the efficiency of an internal combustion engine has been going on ever since the invention of this reliable work equipment. In recent times much attention has been focused on achieving higher thermal efficiency by reducing the heat loss to the surroundings by the application of “low heat rejection” concept using ceramic coating for engine components or ceramic components itself. In this direction, the present analysis focused on the formulation and development of a two zone combustion model for the prediction of combustion, heat release and performance of the conventionally Water cooled and low heat rejection engines. The low heat rejection concept is introduced in this model by developing and formulating a wall heat transfer model to consider the effect of instantaneous inside surface temperature on combustion and heat release of an LHR engine. The gas wall heat transfer by means of convection and radiation is calculated using various gas wall heat transfer models. The predictions by the computer model and experimental findings are demonstrated. The capability of this model and the comparison of the predicted results with experimental findings are highly satisfactory.
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Raporty organizacyjne na temat "Low temperature heat engine"

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Wiczynski, T. A., i T. A. Marolewski. Development of high temperature liquid lubricants for low-heat rejection heavy duty diesel engines. Office of Scientific and Technical Information (OSTI), marzec 1993. http://dx.doi.org/10.2172/140583.

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Stillman, Greg, i Samuel P. Weaver. Low-temperature Stirling Engine for Geothermal Electricity Generation. Office of Scientific and Technical Information (OSTI), marzec 2013. http://dx.doi.org/10.2172/1073635.

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Frame, Edward A., Alan F. Montemayor i Edwin C. Owens. Low-Temperature Pumpability of U.S. Army Diesel Engine Oils. Fort Belvoir, VA: Defense Technical Information Center, grudzień 1987. http://dx.doi.org/10.21236/ada197847.

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Frame, E. A., i W. E. Likos. Low-Temperature Oil Pumpability Investigations in a 6.2L Diesel Engine. Fort Belvoir, VA: Defense Technical Information Center, sierpień 2000. http://dx.doi.org/10.21236/ada382457.

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Charoenphonphanich, Chinda, Wittawat Imerb, Preechar Karin, Nuwong Chollacoop i Katsunori Hanamura. Low Temperature Starting Techniques for Ethanol Engine without Secondary Fuel Tank. Warrendale, PA: SAE International, listopad 2011. http://dx.doi.org/10.4271/2011-32-0552.

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Anderson, James H. Jr, i Benjamin W. Dambly. Low Temperature Heat Source Utilization Current and Advanced Technology. Office of Scientific and Technical Information (OSTI), czerwiec 1992. http://dx.doi.org/10.2172/860859.

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Johnson, R. K. Measured Performance of a Low Temperature Air Source Heat Pump. Office of Scientific and Technical Information (OSTI), wrzesień 2013. http://dx.doi.org/10.2172/1260317.

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Thekdi, Arvind, Sachin Nimbalkar, Senthil Sundaramoorthy, Kristina Armstrong, Anthony Taylor, Jack Gritton, Thomas Wenning i Joe Cresko. Technology Assessment on Low-Temperature Waste Heat Recovery in Industry. Office of Scientific and Technical Information (OSTI), wrzesień 2021. http://dx.doi.org/10.2172/1819547.

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Clark, Nigel N., Francisco Posada, Clinton Bedick, John Pratapas, Aleksandr Kozlov, Martin Linck i Dmitri Boulanov. Low Temperature Combustion with Thermo-Chemical Recuperation to Maximize In-Use Engine Efficiency. Office of Scientific and Technical Information (OSTI), marzec 2009. http://dx.doi.org/10.2172/1044058.

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Hays, Lance G. Scale Resistant Heat Exchanger for Low Temperature Geothermal Binary Cycle Power Plant. Office of Scientific and Technical Information (OSTI), listopad 2014. http://dx.doi.org/10.2172/1183048.

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