Artykuły w czasopismach: „Low temperature heat engine”

1

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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TAKEUCHI, Makoto, i Shinji SUZUKI. "Characteristics of Low Temperature Stirling Engine at Heat Pump Operation". Proceedings of the Symposium on Stirlling Cycle 2000.4 (2000): 157–60. http://dx.doi.org/10.1299/jsmessc.2000.4.157.

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Kurhe, Niranjan, Adinath Funde, Pritesh Gokhale, Sandesh Jadkar, Subhash Ghaisas i Abhijit Date. "Development of Low Temperature Heat Engine for Water Pumping Application". Energy Procedia 110 (marzec 2017): 292–97. http://dx.doi.org/10.1016/j.egypro.2017.03.142.

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Smith, James E., i Randy Churchill. "A Concept Review of Low-Heat-Rejection Engines". Applied Mechanics Reviews 42, nr 3 (1.03.1989): 71–90. http://dx.doi.org/10.1115/1.3152422.

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Insulated engines have become popular ideas with the development of new materials and material processing techniques. Several research groups have been involved and are producing needed, quality information about low-heat-rejection engines. To date, a comprehensive review has not been presented, like the work included here, that identifies and discusses the various programs and results, or even the breadth of the different topics being undertaken. This paper presents a comprehensive literature review of low-heat-rejection engine concepts and brief discussions of some modeling techniques, both heat transfer models and engine models, being used to further the knowledge base in this field. The general, established concepts and history of low-heat-rejection engines are briefly covered before each individual area of interest is presented. These are temperatures of low-heat-rejection engines, new material requirements, new construction techniques to facilitate the new materials, tribology, emissions, noise concerns, new fuel capabilities, and exhaust heat utilization. The importance of a “whole system” approach is stressed. Inconsistencies in the literature are also discussed.

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Hoegel, Benedikt, Dirk Pons, Michael Gschwendtner, Alan Tucker i Mathieu Sellier. "Thermodynamic peculiarities of alpha-type Stirling engines for low-temperature difference power generation: Optimisation of operating parameters and heat exchangers using a third-order model". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 228, nr 11 (20.11.2013): 1936–47. http://dx.doi.org/10.1177/0954406213512120.

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Low-temperature heat sources such as waste heat and geothermal energy in the range from 100 ℃ to 200 ℃ are widely available and their potential is largely untapped. Stirling engines are one possibility to convert this heat to a usable power output. Much work has been done to optimise Stirling engines for high-temperature heat sources such as external combustion or concentrated solar energy but only little is known about suitable engine layouts at lower temperature differences. With the reduced temperature difference, changes become necessary not only in the heat exchangers and the regenerator but also in the operating parameters such as frequency and phase angle. This paper shows results obtained from a third-order simulation model that help to identify beneficial parameter combinations, and explains the differences of low and high-temperature engines.

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Menacer, Brahim, Naima Khatir, Mostefa Bouchetara, Ahmed Amine Larbi i Cherif Belhout. "The Heat Transfer Study in the Diesel Engine Combustion Chamber Using a Two-Zone Combustion Model". Mathematical Modelling of Engineering Problems 7, nr 4 (18.12.2020): 614–20. http://dx.doi.org/10.18280/mmep.070414.

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The study of heat transfer phenomena in diesel engines is a very complex task considering the number of engine components such as intake and exhaust manifolds, lubricant oil and coolant subsystems, the different heat transfer mechanisms (conduction, convection, and radiation). This paper presents simulation results using a dual-zone model associated to GT-Suite simulation software for the calculation of convective heat transfer from gas to the cylinder wall, radiation heat transfer, gas pressure and temperature for low, partial and full load engine as a function of crank angle for a single-cylinder diesel engine. In this present article, a numerical simulation model was created to foresee the main combustion characteristics, and the simulated results were approved through the reference experiment data. Simulation results showed that any increase in the mass of fuel injected into the combustion chamber would generate a significant increase in the level of pressure and temperature of the combustion gases in the cylinder. This means that despite the improved power performance, excessive fuel consumption would have a negative effect on the thermal behavior and consequently on the life of the engine. The essential objective of any combustion engine development is to reduce fuel consumption while maintaining or improving the engine's power output.

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KATO, Yoshitaka, i Fumio SHIMADA. "113 Conversion of low temperature differential Stirling engine for lower temperature heat source". Proceedings of the Tecnology and Society Conference 2014 (2014): 5–6. http://dx.doi.org/10.1299/jsmetsd.2014.5.

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Liu, Yang, Yituan He, Cuijie Han i Chenheng Yuan. "Combustion and energy distribution of hydrogen-enriched compressed natural gas engines with low heat rejection based on Atkinson cycle". Advances in Mechanical Engineering 11, nr 1 (styczeń 2019): 168781401881958. http://dx.doi.org/10.1177/1687814018819580.

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In order to reduce the heat loss and improve the indicated thermal efficiency of hydrogen-enriched compressed natural gas engines, this article presents a combination of Atkinson cycle with high compression ratio and low heat rejection on the hydrogen-enriched compressed natural gas prototype engine with 55% hydrogen blend. The combustion characteristics and energy distribution of the prototype and modified engines were investigated by simulation, and the conclusions are as follows: the pressure and temperature of modified engines are higher than those of the prototype during the combustion process. Compared with the prototype, the modified engines present lower peak heat release rate, but faster combustion after ignition, and their CA50 are closer to top dead center. Although the high compression ratio engine with Atkinson cycle generates more heat loss, its indicated thermal efficiency still increases by 0.6% with the decrease in the exhaust energy. Furthermore, the high compression ratio engine with low heat rejection and Atkinson cycle combines the advantages of low heat loss and relatively longer expansion stroke, so its heat loss reduces obviously, and 61.6% of the saved energy from low heat rejection and Atkinson cycle can be converted into indicated work that indicates a 4.5% improvement in indicated thermal efficiency over the prototype, which makes it perform better in terms of power and fuel economy simultaneously.

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Kaiser, Sascha, Markus Nickl, Christina Salpingidou, Zinon Vlahostergios, Stefan Donnerhack i Hermann Klingels. "Investigations of the synergy of Composite Cycle and intercooled recuperation". Aeronautical Journal 122, nr 1252 (15.05.2018): 869–88. http://dx.doi.org/10.1017/aer.2018.46.

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ABSTRACTThe synergistic combination of two promising engine architectures for future aero engines is presented. The first is the Composite Cycle Engine, which introduces a piston system in the high pressure part of the core engine, to utilise closed volume combustion and high temperature capability due to instationary operation. The second is the Intercooled Recuperated engine that employs recuperators to utilise waste heat from the core engine exhaust and intercooler to improve temperature levels for recuperation and to reduce compression work. Combinations of both architectures are presented and investigated for improvement potential with respect to specific fuel consumption, engine weight and fuel burn against a turbofan. The Composite Cycle alone provides a 15.6% fuel burn reduction against a turbofan. Options for adding intercooler were screened, and a benefit of up to 1.9% fuel burn could be shown for installation in front of a piston system through a significant, efficiency-neutral weight decrease. Waste heat can be utilised by means of classic recuperation to the entire core mass flow before the combustor, or alternatively on the turbine cooling bleed or a piston engine bypass flow that is mixed again with the main flow before the combustor. As further permutation, waste heat can be recovered either after the low pressure turbine – with or without sequential combustion – or between the high pressure and low pressure turbine. Waste heat recovery after the low pressure turbine was found to be not easily feasible or tied to high fuel burn penalties due to unfavourable temperature levels, even when using sequential combustion or intercooling. Feasible temperature levels could be obtained with inter-turbine waste heat recovery but always resulted in at least 0.3% higher fuel burn compared to the non-recuperated baseline under the given assumptions. Consequently, only the application of an intercooler appears to provide a considerable benefit for the examined thermodynamic conditions in the low fidelity analyses of various engine architecture combinations with the specific heat exchanger design. Since the obtained drawbacks of some waste heat utilisation concepts are small, innovative waste heat management concepts coupled with the further extension of the design space and the inclusion of higher fidelity models may achieve a benefit and motivate future investigations.

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Radchenko, Andrii, Mykola Radchenko, Andrii Konovalov i Anatolii Zubarev. "Increasing electrical power output and fuel efficiency of gas engines in integrated energy system by absorption chiller scavenge air cooling on the base of monitoring data treatment". E3S Web of Conferences 70 (2018): 03011. http://dx.doi.org/10.1051/e3sconf/20187003011.

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An advanced scavenge air cooling system for reciprocating gas engines of integrated energy system for combined electricity, heat and refrigeration generation has been developed. New method of deep scavenge air cooling and stabilizing its temperature at increased ambient air temperatures and three-circuit scavenge air cooling system with absorption lithium-bromide chiller and wet-type cooling tower was proposed. Such cooling method does not require essential constructive changes in the existing scavenge air cooling system but only an addition heat exchanger for chilling scavenge air cooling water of scavenge air low-temperature intercooler closed contour by absorption chiller. A chilled water from absorption chiller is used as a coolant. To evaluate the effect of gas engine scavenge air deeper cooling compared with its typical radiator cooling, data on the dependence of fuel consumption and power output of gas engine on ambient air temperature at the inlet of the radiator are analized. The efficiency of engine scavenge air deep cooling at increased ambient air temperatures was estimated by reducing the gas fuel consumption compared with radiator cooling.

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KATO, Yoshitaka, i Fumio SHIMADA. "M06 Low Temperature Differential Stirling Engine Using Channel Shaped Heat Exchanger". Proceedings of the Symposium on Stirlling Cycle 2012.15 (2012): 73–74. http://dx.doi.org/10.1299/jsmessc.2012.15.73.

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Meir, Avishai, Avshalom Offner i Guy Z. Ramon. "Low-temperature energy conversion using a phase-change acoustic heat engine". Applied Energy 231 (grudzień 2018): 372–79. http://dx.doi.org/10.1016/j.apenergy.2018.09.124.

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Sun, Wei Dong, Qi Fen Li, Lin Hui Zhao, Li Fei Song i Xin Zhao. "The Study of Medium/Low-Temperature Stirling Engine Power Output Characteristics". Advanced Materials Research 860-863 (grudzień 2013): 1431–35. http://dx.doi.org/10.4028/www.scientific.net/amr.860-863.1431.

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Stirling engine has the characteristics of diversification of heat source and high thermal power conversion efficiency. It has broad application prospects in using low-grade energy, such as solar energy, biomass emergy and industrial waste heat. In this paper, Schmidt Method used in the Stirling engine working cycle is analyzed theoretically, and the Stirling engine power output is calculated. The effects of temperature and the average cycle pressure on the output characteristics of the system are analyzed. Theoretical calculations show that the output characteristics can be improved significantly by adjusting the heating temperature and the average cycle pressure. An experiment station is then designed and constructed for the research on Stirling engine power output characteristics. Experimental results show that by improving pre-charge pressure in the working chamber with low temperature conditions, the system can achieve higher power output and thermal efficiency. Pre-charge pressure in the working chamber is adjusted to 2MPa, when the heater tube wall temperature reaches 650 °C, the output power exceeds 1750W, and the effective efficiency will be 23.3%.

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Sedlák, Josef, Adam Glváč i Andrej Czán. "Design of stirling engine operating at low temperature difference". MATEC Web of Conferences 157 (2018): 04003. http://dx.doi.org/10.1051/matecconf/201815704003.

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There are many sources of free energy available in the form of heat that is often simply wasted. The aim of this paper is to design and build a low temperature differential Stirling engine that would be powered exclusively from heat sources such as waste hot water or focused solar rays. A prototype is limited to a low temperature differential modification because of a choice of ABSplus plastic as a construction material for its key parts. The paper is divided into two parts. The first part covers a brief history of Stirling engine and its applications nowadays. Moreover, it describes basic principles of its operation that are supplemented by thermodynamic relations. Furthermore, an analysis of applied Fused Deposition Modelling has been done since the parts with more complex geometry had been manufactured using this additive technology. The second (experimental) part covers 4 essential steps of a rapid prototyping method - Computer Aided Design of the 3D model of Stirling engine using parametric modeller Autodesk Inventor, production of its components using 3D printer uPrint, assembly and final testing. Special attention was devoted to last two steps of the process since the surfaces of the printed parts were sandpapered and sprayed. Parts, where an ABS plus plastic would have impeded the correct function, had been manufactured from aluminium and brass by cutting operations. Remaining parts had been bought in a hardware store as it would be uneconomical and unreasonable to manufacture them. Last two chapters of the paper describe final testing, mention the problems that appeared during its production and propose new approaches that could be used in the future to improve the project.

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Shrirao, Pankaj N., Parvezalam I. Shaikh, Farazuddin Zafaruddin i A. N. Pawar. "An Experimental Investigation on Engine Exhaust Emissions of a Low Heat Rejection (Mullite Coated) Single Cylinder Diesel Engine". Advanced Materials Research 588-589 (listopad 2012): 344–48. http://dx.doi.org/10.4028/www.scientific.net/amr.588-589.344.

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Tests were performed on a single cylinder, four stroke, direct injection, diesel engine whose piston crown, cylinder head and valves were coated with a 0.5 mm thickness of 3Al2O3.2SiO2(mullite) (Al2O3= 60%, SiO2= 40%) over a 150 µm thickness of NiCrAlY bond coat. The working conditions for the conventional engine (without coating) and LHR (mullite coated) engine were kept exactly same to ensure a comparison between the two configurations of the engine. This paper is intended to emphasis on emission characteristics of diesel engine with and without mullite coating under identical conditions. Tests were carried out at same operational constraints i.e. air-fuel ratio and engine speed conditions for both conventional engine (without coating) and LHR (mullite coated) engines. The results showed that, there was as much as29.41% and 24.35% decreasing on CO and HC emissions respectively for LHR (mullite coated) engine compared to conventional engine (without coating) at full load. The average decrease in smoke density in the LHR engine compared with the conventional engine was 13.82 % for full engine load. However, there was as much as 20% increasing on NOx emission for LHR engine compared to conventional engine at full load. Also the results revealed that, there was as much as 22% increasing on exhaust gas temperature for LHR engine compared to conventional engine at full engine load.

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Радченко, Микола Іванович, Дмитро Вікторович Коновалов, Чжан Цян, Лю Шаоцзюнь, Луо Зевей i Джі Ран. "ОХОЛОДЖЕННЯ НАДДУВНОГО ПОВІТРЯ ГОЛОВНОГО СУДНОВОГО ДВИГУНА ЕЖЕКТОРНОЮ ХОЛОДИЛЬНОЮ МАШИНОЮ В ЕКВАТОРІАЛЬНИХ ШИРОТАХ". Aerospace technic and technology, nr 2 (27.04.2020): 24–29. http://dx.doi.org/10.32620/aktt.2020.2.04.

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The efficiency of cooling the scavenge air of the main low-speed engine of the transport vessel during operation in the equatorial tropical latitudes is analyzed. The peculiarity of the tropical climate is the high relative humidity of the air at the same time its high temperatures and temperatures of seawater. The cooling of the s scavenge air with a refrigerant ejector chiller was investigated by transforming the scavenge air heat into the cold. With this, the potentially possible minimum temperature of the cooled air was determined considering the boiling temperature of the refrigerant and the temperature differences in the heat exchangers of the intermediate water cooling circuit. Refrigerant ejector chiller is used as the most simple and reliable in design. However, the efficiency of converting the heat to cold by ejector chillers is low: their coefficients of performance are approximately 0.3. Circuit-design solution of three-stage cooling system of scavenging air of ship's main engine - in high-temperature (cogeneration) stage using the extracted heat of scavenging air to get cold with ejector chiller and traditional stage for cooling scavenge air by seawater and low-temperature cooling stage by ejector chiller. The effect of deeper cooling of the scavenge air was determined in comparison with the cooling of the scavenge air with seawater, taking into account the changing climatic conditions during the route of the vessel. It is shown that because of the insufficiently high efficiency of transformation of the scavenge air heat by the ejector chiller (low coefficients of performance) the obtained cooling capacity is not sufficient to cool the scavenge air to a potentially possible minimum temperature of 22 °C when operating the ship engine in tropical climates. However, the heat deficit is relatively small and can be covered by the use of additional exhaust gas heat.

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Sadowski, Tomasz, i Przemysław Golewski. "The Analysis of Heat Transfer and Thermal Stresses in Thermal Barrier Coatings under Exploitation". Defect and Diffusion Forum 326-328 (kwiecień 2012): 530–35. http://dx.doi.org/10.4028/www.scientific.net/ddf.326-328.530.

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Effectiveness of internal combustion turbines in aero-engines is limited by comparatively low temperature of exhaust gas at the entry to turbine of the engine. A thermal efficiency and other capacities of turbine strongly depend on the ratio of the highest to the lowest temperature of a working medium. Continuous endeavour to increase the thermal resistance of engine elements requires, apart from laboratory investigations, also numerical studies in 3D of different aero-engine parts. In the present work, the effectiveness of the protection of turbine blades by thermal barrier coating and internal cooling under thermal shock cooling was analysed numerically using the ABAQUS code. The phenomenon of heating the blade from temperature of combustion gases was studied. This investigation was preceded by the CFD analysis in the ANSYS Fluent program which allows for calculation of the temperature of combustion gases. The analysis was conducted for different levels of the shock temperature, different thickness of applied TBC, produced from different kinds of materials.

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Gu, Xiaoyong, Guohe Jiang, Zhenghua Guo i Shangzhi Ding. "Design and Experiment of Low-Pressure Gas Supply System for Dual Fuel Engine". Polish Maritime Research 27, nr 2 (1.06.2020): 76–84. http://dx.doi.org/10.2478/pomr-2020-0029.

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AbstractA low-pressure gas supply system for dual fuel engines was designed to transport liquid natural gas from a storage tank to a dual fuel engine and gasify it during transportation. The heat exchange area and pressure drop in the spiral- wound heat exchanger, the volume of the buffer tank and the pressure drop in the pipeline of the gas supply system were calculated by programming using Python. Experiments were carried out during the process of starting and running the dual fuel engine using this gas supply system. Experimental data show that the gas supply system can supply gas stably during the process and ensure the stable operation of the dual fuel engine. The effects of the parameters of natural gas and ethylene glycol solution on the heat exchange area of the spiral-wound heat exchanger and the volume of the buffer tank in the gas supply system were studied. The results show that the heat exchange area calculated according to pure methane can adapt to the case of non-pure methane. The temperature difference between natural gas and ethylene glycol solution should be increased in order to reduce the heat exchange area. The heat exchange area selected according to the high pressure of natural gas can adapt to the low pressure of natural gas. The volume of the buffer tank should be selected according to the situation of the minimum methane content to adapt to the situation of high methane content. The main influencing factor in selecting the volume of the buffer tank is the natural gas flow. The results can provide guidance for the design of the gas supply system for dual fuel engines.

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Kropiwnicki, Jacek, i Aleksandra Szewczyk. "Stirling Engines Powered by Renewable Energy Sources". Applied Mechanics and Materials 831 (kwiecień 2016): 263–69. http://dx.doi.org/10.4028/www.scientific.net/amm.831.263.

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Stirling engine is a device that produces mechanical energy using heat from any source of energy, without the need of combustion of any fuel inside the device. Renewable energy sources, which are mostly low-temperature energy sources, can be used to produce mechanical and electrical energy in Stirling engines. The paper presents an overview of the existing prototype Stirling engines designed for using of low-temperature energy sources, including renewable energy sources. Commercial devices for electric power generation offered for use in home, usually do not exceed 1 kW. Using the Schmidt model, the analyze of influence of temperature working fluid in the expansion space (heater) on the efficiency and the electric power generated in the Stirling engine of alpha type has been presented in the paper.

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Ciniviz, Murat. "PERFORMANCE AND ENERGY BALANCE OF A LOW HEAT REJECTION DIESEL ENGINE OPERATED WITH DIESEL FUEL AND ETHANOL BLEND". Transactions of the Canadian Society for Mechanical Engineering 34, nr 1 (marzec 2010): 93–104. http://dx.doi.org/10.1139/tcsme-2010-0006.

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In this study, it was aimed to investigate the effect of ceramic coating on a turbocharged diesel engine performance and energy balance. For this purpose, cylinder head, valves and pistons of the engine were coated with yttria stabilized zirconia layer with a thickness of 0.35 mm nickel-chromium- aluminium bond coat, as well as the atmospheric plasma spray coating method with a thickness of 0.15 mm. Then, the engines were tested for full load. The heating values of the diesel fuel and ethanol were 46.2 and 25.182 MJ/kg, respectively. Because of the lower heating values of the ethanol, compared with the diesel fuel, it appears to have lower following to engine power, torque and SFC. Compare to engine power of SDE, LHRe has increased about 2%, LHReth has decreased about 22% at all engine speed. Compare to engine torque of SDE, LHRe has increased about 2.5%, LHReth has decreased about 23 % at all engine speeds. Compare to SFC of SDE, LHRe has decreased about 1.1 %, LHReth has increased about 54 % at all engine speeds. Compare to exhaust turbine inlet temperature of SDE, LHRe has increased about 15 %, LHReth has decreased about 17 % at all engine speeds.

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Zeeshan, Muhammad Uzair Mehmood i Sungbo Cho. "Optimization of a Thermomagnetic Heat Engine for Harvesting Low Grade Thermal Energy". Energies 14, nr 18 (13.09.2021): 5768. http://dx.doi.org/10.3390/en14185768.

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Thermomagnetic energy harvesters are one form of technology that can be effectively used to extract energy from low grade heat sources, without causing damage to the environment. In this study, we investigated the output performance of our previously designed thermomagnetic heat engine, which was developed to extract thermal energy by exploiting the magnetocaloric effect of gadolinium. The proposed heat engine uses water as the heat transfer fluid, with heat sources at a temperature in the range 20–65 °C. Although this method turned out to be a promising solution to extract thermal energy, the amount of energy extracted through this geometry of thermomagnetic engine was limited and depends on the interaction between magnetic flux and magnetocaloric material. Therefore, in this paper we carry out an in-depth analysis of the designed thermomagnetic heat engine with an integrated approach of numerical simulation and experimental validation. The computational model improved recognition of the critical component to developing an optimized model of the thermomagnetic heat engine. Based on the simulation result, a new working model was developed that showed a significant improvement in the rpm and axial torque generation. The results indicate that the peak RPM and torque of the engine are improved by 34.3% and 32.2%, respectively.

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Радченко, Андрій Миколайович, Дмитро Вікторович Коновалов, Іван Володимирович Калініченко, Чен Нінь i Хан Баочен. "ОХОЛОДЖЕННЯ НАДДУВНОГО ПОВІТРЯ ГОЛОВНОГО СУДНОВОГО ДВИГУНА АБСОРБЦІЙНОЮ БРОМИСТОЛІТІЄВОЮ ХОЛОДИЛЬНОЮ МАШИНОЮ В ЕКВАТОРІАЛЬНИХ ШИРОТАХ". Aerospace technic and technology, nr 2 (27.04.2020): 30–35. http://dx.doi.org/10.32620/aktt.2020.2.05.

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The efficiency of cooling the scavenge air of the main low-speed engine of the transport vessel during operation in the equatorial tropical latitudes is analyzed. The peculiarity of the tropical climate is the high relative humidity of the air at the same time its high temperatures and temperatures of seawater. The cooling of the scavenge air with an absorption lithium bromide chiller by transforming the scavenge air heat into the cold was investigated. With this, the potentially possible minimum temperature of the cooled air was determined considering the temperature of the cold water (coolant) from the absorption lithium bromide chiller and the temperature differences in the heat exchangers of the intermediate water circuit of cooling. Absorption lithium bromide chillers are characterized by high efficiency of transformation of waste heat into cold - high coefficients of performance. Circuit-design solution of three-stage cooling system of scavenging air of ship's main engine - in high-temperature (cogeneration) stage using the extracted heat of scavenging air to get cold with absorption chiller and traditional stage for cooling scavenge air by seawater and low-temperature cooling stage by absorption chiller. The effect of deeper cooling of the scavenge air was determined in comparison with the cooling of the scavenge air with seawater, taking into account the changing climatic conditions during the route of the vessel. It is shown that due to the high efficiency of heat transformation in absorption chillers (high coefficients of performance 0.7…0.8), there is a significant amount of excess heat of scavenging air over the heat required to cool it to 22 °C, which reaches almost half of the available scavenge air heat on the Shanghai-Singapore-Shanghai route. This reveals the possibility of additional cooling the inlet of the turbocharger of the engine with the achieving almost double fuel economy due to the cooling of all cycle air of the low-speed engine, including the air at the inlet.

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Kim, Yeongmin, Wongee Chun i Kuan Chen. "Thermal-Flow Analysis of a Simple LTD (Low-Temperature-Differential) Heat Engine". Energies 10, nr 4 (21.04.2017): 567. http://dx.doi.org/10.3390/en10040567.

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Kim, Yeongmin, Won Sik Kim, Haejun Jung, Kuan Chen i Wongee Chun. "Thermal-flow analysis of a simple LTD (Low-Temperature-Differential) heat engine". Journal of Energy Engineering 26, nr 1 (31.03.2017): 9–22. http://dx.doi.org/10.5855/energy.2017.26.1.009.

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Izumida, Yuki. "Nonlinear dynamics analysis of a low-temperature-differential kinematic Stirling heat engine". EPL (Europhysics Letters) 121, nr 5 (1.03.2018): 50004. http://dx.doi.org/10.1209/0295-5075/121/50004.

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TODA, Fujio, Takahiro WATANABE i Terumasa SHIRAKI. "M02 Development of LED Exhaust-Heat-Recovering Low-temperature Difference Stirling Engine". Proceedings of the Symposium on Stirlling Cycle 2013.16 (2013): 59–60. http://dx.doi.org/10.1299/jsmessc.2013.16.59.

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TODA, Fujio, Sota OKADA, Tsubasa HIGANO i Honami USUI. "M03 Development of LED Exhaust-Heat-Recovering Low-temperature Difference Stirling Engine". Proceedings of the Symposium on Stirlling Cycle 2014.17 (2014): 83–84. http://dx.doi.org/10.1299/jsmessc.2014.17.83.

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Mumith, J. A., C. Makatsoris i T. G. Karayiannis. "Design of a thermoacoustic heat engine for low temperature waste heat recovery in food manufacturing". Applied Thermal Engineering 65, nr 1-2 (kwiecień 2014): 588–96. http://dx.doi.org/10.1016/j.applthermaleng.2014.01.042.

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Ahn, Joon, i Seok Yeon Kim. "Performance of Novel High Temperature Heat Exchanger for 1 kW Class Stirling Engine Considering Heat Recovery". International Journal of Air-Conditioning and Refrigeration 24, nr 01 (marzec 2016): 1650007. http://dx.doi.org/10.1142/s2010132516500073.

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This research proposed a novel shape design by integrating the geometry that showed the best performance including fin length, pitch and angle on the high temperature heat exchanger of Stirling engine designed for the prime mover of 1kW cogeneration system for home. First, the numerical simulation was conducted on the new design and existing shape, and the performance improvement according to the shape optimization was checked. Next, the validity of its performance was verified by additionally considering the heat loss from the recuperation and low-temperature heat exchanger. As a result, when the high temperature heat exchanger is optimized, a great amount of heat quantity is absorbed from the fuel gas from the upstream part where negative heat flux occurred in the cylinder head part. This was judged to be because of the fixed temperature of the high-temperature part in the thermodynamic cycle. Thus, when researching the shape of the high-temperature heat exchanger, an optimized geometry can be obtained when combining cycle interpretation of system rather than interpreting independently.

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Li, Da, Qiang Sun, Ke Sun, Guodong Zhang, Shuzhan Bai i Guoxiang Li. "Diesel engine waste heat recovery system comprehensive optimization based on system and heat exchanger simulation". Open Physics 19, nr 1 (1.01.2021): 331–40. http://dx.doi.org/10.1515/phys-2021-0039.

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Abstract To further improve the thermal efficiency of diesel engines, a waste heat recovery system model utilizing organic Rankine cycle (ORC) is constructed and verified through system bench test and heat exchanger bench test. To recover waste heat from diesel engine exhaust, ethanol, cyclopentane, cyclohexane, R1233zd (E), and R245fa were selected for comparison. The quality of heat source, the quality of evaporator, the system output, and the system complicity were taken as variables for comparison. Analysis shows that for ORC systems without recuperator, ethanol system has the best system output of the five in a wide operation temper range, with the highest exergy efficiency of 24.1%, yet the exergy efficiency increase after the application of recuperator, 9.0%, is limited. For low temperature exhaust, cyclopentane system has the best performance with or without recuperator, and the cyclopentane system with recuperator has the best performance in terms of exergy efficiency, 27.6%, though complex heat exchangers are also required for high power output. The system output of the R1233zd system is better than the R245fa system, yet the advantage of low evaporate temperature can be better utilized for low quality waste heat recovery.

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Janardhan, N., M. V. S. Murali Krishna, P. Ushasri i P. V. K. Murthy. "Performance Evaluation of a Low Heat Rejection Diesel Engine with Jatropha Oil". International Journal of Engineering Research in Africa 11 (październik 2013): 27–44. http://dx.doi.org/10.4028/www.scientific.net/jera.11.27.

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Investigations were carried out to evaluate the performance of a low heat rejection (LHR) diesel engine consisting of air gap insulated piston with 3-mm air gap, with superni (an alloy of nickel) crown, air gap insulated liner with superni insert and ceramic coated cylinder head with different operating conditions of crude jatropha oil (CJO) with varied injection timing and injector opening pressure . Performance parameters [brake thermal efficiency, exhaust gas temperature, coolant load and volumetric efficienc and exhaust emissions [smoke and oxides of nitroge were determined at various values of brake mean effective pressure (BMEP). Combustion characteristics [ peak pressure, time of occurrence of peak pressure and maximum rate of pressure ris of the engine were at peak load operation of the engine. Conventional engine (CE) showed deteriorated performance, while LHR engine showed improved performance with vegetable operation at recommended injection timing and pressure. The performance of both versions of the engine improved with advanced injection timing and higher injector opening pressure when compared with CE with pure diesel operation. Relatively, peak brake thermal efficiency increased by 14%, smoke levels decreased by 27% and NOx levels increased by 49% with vegetable oil operation on LHR engine at its optimum injection timing, when compared with pure diesel operation on CE at manufacturers recommended injection timing.

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Labik, Linus Kweku, Bright Kwakye-Awuah, Baah Sefa-Ntiri, Eric Kwabena Kyeh Abavare, Isaac Nkrumah i Craig Williams. "Electricity Generation Using a Hybridized Zeolite Adsorption Heat Pump and Heat Engine". Applied Physics Research 12, nr 4 (31.07.2020): 75. http://dx.doi.org/10.5539/apr.v12n4p75.

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The use of adsorption in Thermal Energy Storage has gained considerable research interest of late. Some applications have focused on the use of TES for transformation of low temperature heat in applications such as cooling and heating. Zeolite and water have been studied as suitable materials. Their characteristics as environmentally friendly materials and high affinity makes them conspicuous. The unique properties of zeolites to hold adsorbed water/heat with very minimal loss is also significant. With the aid of a dynamo, a Stirling engine as heat engine and the adsorption energy storage system serving as heat pump was used to generate electricity. The relationship between electricity generation and temperature was investigated. The obtained average temperature and pressure of the zeolite - water adsorption heat pump was also compared with the basic adsorption cycle.

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Brzeski, L., i Z. Kazimierski. "A New Concept of Externally Heated Engine—Comparisons with the Stirling Engine". Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 210, nr 5 (październik 1996): 363–71. http://dx.doi.org/10.1243/pime_proc_1996_210_060_02.

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This paper presents a new concept of the externally heated valve (EHV) engine. Air can be used as a working medium in the closed cycle of this engine. Heat delivered to the working air can come from a combustion chamber or another heat generator of an arbitrary type. The engine construction and the thermodynamic cycle performed by it are original and entirely different from the well-known Stirling engine. The main disadvantage of the Stirling engine is its low power density, that is the low power obtained per litre of the engine cylinder volume. In the case of the engine presented here it is possible to achieve power density and efficiency similar to those typical of advanced internal combustion engines. Comparisons between the power of the Stirling engine and the power of the new engine have been performed for the same engine capacity, rotational frequency and maximum and minimum temperatures of the cycle. At the same minimum pressure of the working gas in both engines, the power of the EHV engine is several times higher than that of the Stirling engine, while, on the other hand, at the same maximum pressure of the working gas in both engines, the power of the EHV engine is 20 per cent higher than that of the Stirling engine power. The efficiencies of both engines do not differ significantly from each other.

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Zhou, Canzong, Shuyi Chen, Wei Cui i Zhengmao Yao. "System Design of Electricity Generation Using Waste Heat from LNG Automobile". E3S Web of Conferences 145 (2020): 02062. http://dx.doi.org/10.1051/e3sconf/202014502062.

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According to the research, thermoelectricity generation can recycle the heat contained in the cooling system of internal combustion engine. This paper is about taking advantage of the feature in the huge temperature difference at about 560 °C which is formed between high-temperature engine and LNG (Liquefied Natural Gas) in low temperature and the ability that LNG provides semiconductor with thermoelectric conversion material so as to produce the maximum output voltage in low temperature. We take advantage of lead telluride materials that adapt to the high temperature environment and bismuth telluride materials that adapt to the low temperature environment, both of which forms a circuit and are designed as a thermoelectric power generation device. Also, we confirm the possibility of applying the device to cars.

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Mayorov, V. A., i V. F. Shcherbakov. "Power Plants Based on a Steam Drive with a Working Body Closed Circulation". Agricultural Machinery and Technologies 15, nr 1 (24.03.2021): 71–77. http://dx.doi.org/10.22314/2073-7599-2021-15-1-71-77.

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The authors investigated the heat carriers thermodynamic characteristics and the power plant structural components, which ensured the efficient conversion of thermal energy into mechanical and electrical energy.(Research purpose) To conduct modeling for calculating the structure manufacturing technology and studying the power plant characteristics based on a steam engine with given energy parameters.(Materials and methods) The authors carried out mathematical modeling based on the heat and mass transfer laws. To create a prototype model of a steam engine, the recuperation principle based on the “liquid–vapor–liquid” cycle with the use of low-temperature heat carriers was used.(Results and discussion) The authors showed that double transformation of the aggregation state of the working body was much more efficient than its heating. They calculated the characteristics connecting the energy processes of low-temperature heat carriers vaporization (freon R-134a) in the radiator and engine. They revealed dependencies: the radiator heating time from 30 degrees Celsius (ambient temperature) to 100 degrees (maximum operating temperature) at different powers of the heating source (3; 4; 5 kilowatts); density and average density of steam in the radiator from temperature; the steam engine power and the freon steam consumption from the pressure of 0-3.97 megapascals.(Conclusions) The authors determined that the working steam amount, proportional to its density at a temperature of 90 degrees and a pressure of 3.6 megapascals, was 4.75 times less than the liquid freon amount, proportional to its density, at 100 degrees Celsius and a pressure of 3.97 megapascals, the working steam amount was 2 times less than liquid freon. They revealed a limited range of operating temperatures in a steam engine. It was proved that these calculation methods and characteristics determined the structural and energy parameters of the developed power plants based on a steam engine.

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Shih, Hua-Ju. "An Analysis Model Combining Gamma-Type Stirling Engine and Power Converter". Energies 12, nr 7 (6.04.2019): 1322. http://dx.doi.org/10.3390/en12071322.

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Waste heat is a potential source for powering our living environment. It can be harvested and transformed into electricity. Ohmic heat is a common type of waste heat. However, waste heat has the following limitations: wide distribution, insufficient temperature difference (ΔT < 70 K) for triggering turbines, and producing voltage below the open voltage of the battery. This paper proposes an energy harvester model that combines a gamma-type Stirling engine and variable capacitance. The energy harvester model is different from Tavakolpour-Saleh’s free-piston-type engine [7.1 W at ΔT = 407 K (273–680 K)]. The gamma-type Stirling engine is a low-temperature-difference engine. It can be triggered by a minimum ΔT value of 12 K (293–305 K). The triggering force in the variable capacitance is almost zero. Furthermore, the gamma-type Stirling engine is suitable for harvesting waste heat at room temperature. This study indicates that 21 mW of energy can be produced at ΔT = 30 K (293–323 K) for a bias voltage of 70 V and volume of 103.25 cc. Because of the given bias voltage, the energy harvester can break through the open voltage of the battery to achieve energy storage at a low temperature difference.

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NAKAJIMA, Katsuaki, Fujio TODA, Yoshinori OHYAGI i Kazuhiko KIKUCHI. "Performance Characteristic of the Low Temperature Difference Stirling Engine : Influence of a Low Heat Source". Proceedings of the Symposium on Stirlling Cycle 2003.7 (2003): 53–54. http://dx.doi.org/10.1299/jsmessc.2003.7.53.

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Nie, Lei, Donghai Mei, Haifeng Xiong, Bo Peng, Zhibo Ren, Xavier Isidro Pereira Hernandez, Andrew DeLaRiva i in. "Activation of surface lattice oxygen in single-atom Pt/CeO2 for low-temperature CO oxidation". Science 358, nr 6369 (14.12.2017): 1419–23. http://dx.doi.org/10.1126/science.aao2109.

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To improve fuel efficiency, advanced combustion engines are being designed to minimize the amount of heat wasted in the exhaust. Hence, future generations of catalysts must perform at temperatures that are 100°C lower than current exhaust-treatment catalysts. Achieving low-temperature activity, while surviving the harsh conditions encountered at high engine loads, remains a formidable challenge. In this study, we demonstrate how atomically dispersed ionic platinum (Pt2+) on ceria (CeO2), which is already thermally stable, can be activated via steam treatment (at 750°C) to simultaneously achieve the goals of low-temperature carbon monoxide (CO) oxidation activity while providing outstanding hydrothermal stability. A new type of active site is created on CeO2 in the vicinity of Pt2+, which provides the improved reactivity. These active sites are stable up to 800°C in oxidizing environments.

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Zahari, Faisal, Muhammad Murtadha Othman, Ismail Musirin, Amirul Asyraf Mohd Kamaruzaman, Nur Ashida Salim i Bibi Norasiqin Sheikh Rahimullah. "Design of a Small Renewable Resource Model based on the Stirling Engine with Alpha and Beta Configurations". Indonesian Journal of Electrical Engineering and Computer Science 8, nr 2 (1.11.2017): 360. http://dx.doi.org/10.11591/ijeecs.v8.i2.pp360-367.

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<p>This paper presents the conceptual design of Stirling engine based Alpha and Beta configurations. The performances of Stirling engine based Beta configuration will be expounded elaborately in the discussion. The Stirling engines are durable in its operation that requires less maintenance cost. The methodology for both configurations consists of thermodynamic formulation of Stirling Cycle, Schmidt theory and few composition of flywheel and Ross-Yoke dimension. Customarily, the Stirling engine based Beta configuration will operate during the occurrence of low and high temperature differences emanating from any type of waste heat energy. A straightforward analysis on the performance of Stirling engine based Beta configuration has been performed corresponding to the temperature variation of cooling agent. The results have shown that the temperature variation of cooling agent has a direct effect on the performances of Stirling engine in terms of its speed, voltage and output power. </p>

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Yusof, Mohamad, Z. A. Zainal, N. A. Farid i M. A. Miskam. "An Investigation of a Self-Pressurized Alpha V-Type Stirling Engine Converted Diesel Engine". Applied Mechanics and Materials 699 (listopad 2014): 695–701. http://dx.doi.org/10.4028/www.scientific.net/amm.699.695.

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This study reports the investigation results of 194cc. alpha V-type Stirling engine converted from a four-stroke diesel engine that operated in self-pressurized mode. Tests were conducted with air as the working gas and liquefied petroleum gas (LPG) as the heat source. The engine started operating at 600 °C for hot cylinder temperature and 60 °C for cold cylinder temperature, respectively. At heat input of 1100 J/s, the engine performance was successfully tested at both no load and load conditions. For mechanical shaft power assessment, the engine approximately produced a maximum brake power of 7 W, brake thermal efficiency of 0.6% at 717 rpm speed, 811 °C hot cylinder temperature and 96 °C cold cylinder temperature. For electrical power assessment, the engine was capable of generating a maximum electrical output power of 1.7 We at 657 rpm speed, 855 °C hot cylinder temperature and 98 °C cold cylinder temperature. Despite its low engine performance, the study of alpha V-type Stirling engine is a worthwhile step towards clean and sustainable energy in mass production.

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Boisclair, M. E., D. P. Hoult i V. W. Wong. "Piston Ring Thermal Transient Effects on Lubricant Temperatures in Advanced Engines". Journal of Engineering for Gas Turbines and Power 111, nr 3 (1.07.1989): 543–52. http://dx.doi.org/10.1115/1.3240289.

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One class of advanced diesel engines operates with low heat rejection and high operating temperatures; piston-ring / liner lubrication is a major problem for these engines. This study attempts to illustrate the time-dependent thermal environment around the top piston ring and lubricant in these advanced engines. Particular emphasis will be placed on the maximum lubricant temperature. The analysis starts with a standard cycle simulation and a global finite-element analysis of the piston and liner in relative motion. A more detailed finite-element model, which considers variable oil film thickness on the liner, focuses on the top ring and lubricant and uses the groove and liner temperatures generated in the global analysis as boundary conditions. Results for different heat rejection engine configurations are presented. We observe that because of major transient effects, high lubricant temperature is experienced not only at top ring reversal but also down the liner to bottom ring reversal.

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