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Journal articles on the topic 'Low temperature heat engine'
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1
Kim, Yeongmin, Muhammad Uzair Mehmood, Hyun Joo Han, Yu Jin Kim, Seung Jin Oh, and Sang-Hoon Lim. "Reclaiming Power Potential from Low Temperature Waste Heat by Thermomagnetic Heat Engines." Energies 15, no. 8 (April 12, 2022): 2817. http://dx.doi.org/10.3390/en15082817.
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Thermomagnetic heat engines were designed, constructed, and tested, where numbers of gadolinium (Gd) blocks were used to exploit low temperature waste heat. Gadolinium is a rare earth material whose magnetic property changes with temperature, altering between ferromagnetic and paramagnetic. A motion develops in the thermomagnetic heat engine as Gd blocks are exposed to different temperatures causing changes in their magnetic property. A change in the magnetic property of any Gd block is directly related to the resultant torque driving the thermomagnetic heat engine for power production. Among heat engines studied to date, the cylindrical thermomagnetic heat engine was able to develop a maximum mechanical power of 1.1 W at a temperature difference of 45 °C between hot and cold thermal resources. Furthermore, depending on the effectiveness of an electromagnetic generator (EMG) combined with a triboelectric nanogenerator (TENG), the electric power output can be notably improved.
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Hasanovich, Linda, and David Nobes. "Investigation of effect of heat exchanger size on power output in low-temperature difference Stirling engines." E3S Web of Conferences 313 (2021): 03002. http://dx.doi.org/10.1051/e3sconf/202131303002.
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The Stirling engine is capable of converting any source of thermal energy into kinetic energy, which makes it an attractive option for utilizing low-temperature sources such as geothermal or waste heat below 100 °C. However, at these low temperatures, the effects of losses are proportionally higher due to the lower thermal potential available. One such significant loss is excess dead volume, wherein a significant contributor is the heat exchangers. The heat exchangers must be selected to optimize power output by minimizing the dead volume loss while maximizing the heat transfer to and from the engine. To better understand what the optimal geometry of the heat exchanger components is, a Stirling engine is modelled using a third-order commercial modelling software (Sage) and trends of engine properties of power, temperature, and pressure for different heat exchanger geometries are observed. The results indicate that there is an optimum heat exchanger volume and geometry for low temperature Stirling engines. This optimum is also affected by other engine properties, such as regenerator size and engine speed. These results provide insight into the optimal geometry of these components for low-temperature Stirling engines, as well as providing design guidance for future engines to be built.
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Enomoto, Takeshi, Atsushi Matsuguchi, and Noboru Kagawa. "A Study of Mesh Sheets of 3-kW Stirling Engine." E3S Web of Conferences 313 (2021): 05001. http://dx.doi.org/10.1051/e3sconf/202131305001.
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In recent years, the interest in low-pollution and high-efficiency heat engines has been increasing due to the growing awareness of environmental protection, and power generation at relatively low temperatures, such as use of exhaust heat and sunlight, has been attracting attention. Compared with other heat engines, Stirling engine is very important because it can be driven by any heat source at low temperatures, such as exhaust heat, and it does not emit exhaust gas. In order to realize a more efficient Stirling engine, it is essential to design a heat exchange system that is suitable for each component. Performance measurement and analysis on a new mesh regenerator material at low temperature difference using a 2-piston alpha-type 3-kW Stirling engine, NS03T are carried out. Mesh sheets developed for high performance Stirling engines can be designed with CAD and CAM technologies by etching process. For this study, M5 and M7 mesh sheets which are thin sheets of stainless steel with square holes in a grid arrangement, are used. With nitrogen and helium as the working fluid, the engine performance is measured by changing the charge pressure, heating temperature, and engine speed to clarify the flow resistance and heat transfer characteristics of the M5 and M7.
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Goudarzi, Koorosh, and Mohammad Reza Zare. "Improving the Engine Efficiency Using a New Combined Refrigeration Cycle for Low-Temperature Heat Source (Waste Heat Recovery)." Journal of Energy and Power Technology 4, no. 2 (April 19, 2022): 1. http://dx.doi.org/10.21926/jept.2202020.
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Passenger and commercial internal combustion engines have relatively large dissipated thermal energy sources that can be used for initiating thermodynamic refrigeration cycles at low temperatures while improving engine efficiency. Researchers have focused on combined power-refrigeration cycles in past studies. This paper presents the operation and performance of a new combined refrigeration system driven by waste heat recovery within the internal combustion engines. For this purpose, the effects of several parameters on the performance of the cycle are examined. Results show that an increase in the engine water temperature, exhaust gas temperature, part-load ratio (PLR), generator temperature, as well as adsorption evaporator temperature had a positive effect on the performance of the cycle. However, the rise in condenser temperature of the adsorption cooling system leads to bad performance. Also, the results indicate that the application of the adsorption refrigeration cycle in the combined cooling cycle, along with the increase in the refrigeration cycle performance by up to 65%, also improves the efficiency of the internal combustion engine.
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Chen, Lingen, Shengbing Zhou, Fengrui Sun, and Chih Wu. "Optimal Configuration and Performance of Heat Engines with Heat Leak and Finite Heat Capacity." Open Systems & Information Dynamics 09, no. 01 (March 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, and 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, no. 3 (September 30, 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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Hu, Jianjun, Zijia Wu, and Changchun Li. "Research on Energy Management Strategy of Range Extender Electric Vehicle considering Temperature Effect under Different Heat Demands." International Journal of Energy Research 2023 (February 6, 2023): 1–15. http://dx.doi.org/10.1155/2023/9903856.
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In order to further improve the energy utilization of the range extender electric vehicle (REEV), the energy management strategy of the REEV under different heat demands and operating temperatures is studied. Firstly, for reducing the extra fuel consumption caused by engine operating temperature, the influence of engine lubricating oil temperature on the equivalence factor is analyzed, and a novel method is proposed, which can determine the equivalence factor by three parameters, including engine temperature, operating condition type, and battery state of charge (SOC). Secondly, to reduce the influence of frequent engine start/stop on fuel consumption, a method to establish the penalty factor based on battery SOC is proposed. Finally, the engine temperature rise law under low-temperature environment and the compressor drive mode determination method under high-temperature environment are studied according to the heat demand under different ambient temperatures. An adaptive equivalent consumption minimization strategy (ECMS) considering the effect of temperature under different heat demands is proposed on the basis of the above research. The simulation under the worldwide harmonized light vehicle test cycle (WLTC) drive cycle reveals that by using the adaptive ECMS, the vehicle operating cost is reduced by 5.69% in normal temperature environment, 0.53%-2.39% in a low-temperature environment, and 0.2%-2.01% in a high-temperature environment.
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Likos, W. E., and T. W. Ryan. "Experiments With Coal Fuels in a High-Temperature Diesel Engine." Journal of Engineering for Gas Turbines and Power 110, no. 3 (July 1, 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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Hu, Lei, Yangfan Chen, and Qiang Luo. "Simulation and verification of cylinder head’s temperature field for marine low-speed engine." Journal of Physics: Conference Series 2791, no. 1 (July 1, 2024): 012023. http://dx.doi.org/10.1088/1742-6596/2791/1/012023.
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Abstract The high load capacity of marine low-speed engines poses a challenge to the thermal load of the cylinder head and temperature field simulation can guide its structural design and optimization. The 3-dimensional models of the fluid domain for the cooling water and the solid domain for the cylinder head are established and meshed, the fluid domain model is simulated to research the heat transfer pattern by Fluent software, and the surface temperature and heat transfer coefficient of the cooling water is calculated. The thermal boundary conditions of the gas in the cylinder are simulated through the analysis of the engine working process. The temperature of the cylinder head is calculated based on the fluid-structure interaction model with the thermal boundary conditions by Workbench software. The validation of the model is carried out by comparing the simulated and measured temperature data in the heated inner wall of the cylinder head. The research results show that compared with the measured value, the error of simulation results is small, which shows that the model and method are reasonable. The temperature in the inner wall of the combustion chamber is low, which can provide possibilities to appropriately improve the power density of the low-speed engine and reduce the risk of low-temperature corrosion.
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Jiang, Wei Jiang. "The Study of Heat-Engines Based on Refrigerant Phase-Change Circulation." Applied Mechanics and Materials 66-68 (July 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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Nicol-Seto, Michael, and David Nobes. "Experimental evaluation of piston motion modification to improve the thermodynamic power output of a low temperature gamma Stirling engine." E3S Web of Conferences 313 (2021): 04002. http://dx.doi.org/10.1051/e3sconf/202131304002.
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Stirling engines are a variety of heat engines which are capable of using heat from various sources including low temperature renewables. This work examines performance of a lab scale low temperature gamma type Stirling engine with a drive train modified with oval elliptical gears. The gears were added to dwell the engine piston motion to attempt to improve the thermodynamic performance of the engine by better replicating the ideal Stirling cycle. A variety of dwelling piston configurations were tested on both the displacer and power piston. It was observed that that the piston dwelling had the anticipated effect of changing the engine indicator diagrams to more closely resemble the ideal cycle, however there were no substantial improvements to maximum engine power. It was observed that dwelling the displacer piston caused substantial reductions to engine running speeds and resulted in maximum power being reduced. In the case of power piston dwelling the indicator diagram was enlarged and there were slight increases to maximum power production. Overall the added complexity of dwelled piston motion systems is not likely an advantageous method of increasing the power output of low temperature difference Stirling engines.
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Chérel, Jérôme, Jean-Marc Zaccardi, Bernard Bouteiller, and 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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HONDA, Shogo, and Akira HOSHI. "Prototype Stirling Engine using Low Temperature Heat Source." Proceedings of the Tecnology and Society Conference 2022 (2022): 323. http://dx.doi.org/10.1299/jsmetsd.2022.323.
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Kawaguchi, Akio, Yoshifumi Wakisaka, Naoki Nishikawa, Hidemasa Kosaka, Hideo Yamashita, Chikanori Yamashita, Hiroki Iguma, Kenji Fukui, Noriyuki Takada, and Terutoshi Tomoda. "Thermo-swing insulation to reduce heat loss from the combustion chamber wall of a diesel engine." International Journal of Engine Research 20, no. 7 (June 10, 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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Kornienko, Victoria, Roman Radchenko, Mykola Radchenko, Andrii Radchenko, Anatoliy Pavlenko, and Dmytro Konovalov. "Cooling Cyclic Air of Marine Engine with Water-Fuel Emulsion Combustion by Exhaust Heat Recovery Chiller." Energies 15, no. 1 (December 30, 2021): 248. http://dx.doi.org/10.3390/en15010248.
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The fuel efficiency of marine diesel engine as any combustion engine falls with raising the temperature of air at the suction of its turbocharger. Therefore, cooling the engine turbocharger intake air by recovering exhaust gas heat to refrigeration capacity is a very perspective trend in enhancing the fuel efficiency of marine diesel engines. The application of water-fuel emulsion (WFE) combustion enables the reduction of a low-temperature corrosion, and, as a result, provides deeper exhaust gas heat utilization in the exhaust gas boiler (EGB) to the much lower temperature of 90–110 °C during WFE instead of 150–170 °C when combusting conventional fuel oil. This leads to the increment of the heat extracted from exhaust gas that is converted to refrigeration capacity by exhaust heat recovery chiller for cooling engine turbocharger sucked air accordingly. We experimentally investigated the corrosion processes on the condensation surfaces of EGB during WFE combustion to approve their intensity suppression and the possibility of deeper exhaust gas heat utilization. The fuel efficiency of cooling intake air at the suction of engine turbocharger with WFE combustion by exhaust heat recovery chiller was estimated along the voyage line Mariupol–Amsterdam–Mariupol. The values of available refrigeration capacity of exhaust heat recovery chiller, engine turbocharger sacked air temperature drop, and corresponding reduction in specific fuel consumption of the main low-speed diesel engine at varying actual climatic conditions on the voyage line were evaluated.
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Reddy, Ch Kesava, M. V. S. Murali Krishna, P. V. K. Murthy, and T. Ratna Reddy. "Performance Evaluation of a Low-Grade Low-Heat-Rejection Diesel Engine with Crude Pongamia oil." ISRN Renewable Energy 2012 (March 15, 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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Petkovic, Snezana, Radivoje Pesic, and 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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Hoegel, Benedikt, Dirk Pons, Michael Gschwendtner, Alan Tucker, and 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, no. 11 (November 20, 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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Granovskiy, Mikhail. "An Adsorption-Desorption Heat Engine for Power Generation from Waste Heat." Journal of Energy and Power Technology 05, no. 04 (November 14, 2023): 1–16. http://dx.doi.org/10.21926/jept.2304034.
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According to the United States Department of Energy, waste heat recovery would allow up to a 20% reduction in greenhouse gases (GHG) emission. Most of the waste energy is discharged as a low-grade heat at temperatures less than 250°C. Therefore, the development of new technologies and the enhancement of existing ones to convert low-grade heat into electrical or mechanical energy are of great importance. The working principle of adsorption-desorption heat pumps with cyclic switching between adsorption and desorption is adapted in the proposed heat engine to generate electrical power from low-temperature heat. Thermodynamic analysis of the heat engine cycle is carried out for the pair adsorbant-adsorbent: CO<sub>2</sub>-activated carbon. Its efficiencies are calculated accepting the ideal gas law and an adsorption-desorption equilibrium at the key points of the cycle. The cycle consists of two isochores and two isotherms like the Stirling engine, but at the same temperature range and without heat regeneration, its thermal efficiency (work per heat supplied) can reach 11.3% vs. 5.0% and specific work 50.7 vs. 3.55 in the latter. The proposed unit has thermal efficiency in the range of Organic Rankine Cycle units and can be utilized in small-scale applications up to 40kWe, where manufacturing cost of turbines or expanders for ORCs increases dramatically. Accounting for quality (temperature) of utilized heat, the proposed cycle’s exergy efficiency, <em>ζ<sub>ex</sub></em> = 34.5% approaches that of water-steam Rankine cycles utilizing natural gas or coal combustion.
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Treacy, Mark, Leilei Xu, Hesameddin Fatehi, Ossi Kaario, and Xue-Song Bai. "Performance of a Methanol-Fueled Direct-Injection Compression-Ignition Heavy-Duty Engine under Low-Temperature Combustion Conditions." Energies 17, no. 17 (August 28, 2024): 4307. http://dx.doi.org/10.3390/en17174307.
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Low-temperature combustion (LTC) concepts, such as homogeneous charge compression ignition (HCCI) and partially premixed combustion (PPC), aim to reduce in-cylinder temperatures in internal combustion engines, thereby lowering emissions of nitrogen oxides (NOx) and soot. These LTC concepts are particularly attractive for decarbonizing conventional diesel engines using renewable fuels such as methanol. This paper uses numerical simulations and a finite-rate chemistry model to investigate the combustion and emission processes in LTC engines operating with pure methanol. The aim is to gain a deeper understanding of the physical and chemical processes in the engine and to identify optimal engine operation in terms of efficiency and emissions. The simulations replicated the experimentally observed trends for CO, unburned hydrocarbons (UHCs), and NOx emissions, the required intake temperature to achieve consistent combustion phasing at different injection timings, and the distinctively different combustion heat release processes at various injection timings. It was found that the HCCI mode of engine operation required a higher intake temperature than PPC operation due to methanol’s low ignition temperature in fuel-richer mixtures. In the HCCI mode, the engine exhibited ultra-low NOx emissions but higher emissions of UHC and CO, along with lower combustion efficiency compared to the PPC mode. This was attributed to poor combustion efficiency in the near-wall regions and engine crevices. Low emissions and high combustion efficiency are achievable in PPC modes with a start of injection around a crank angle of 30° before the top dead center. The fundamental mechanism behind the engine performance is analyzed.
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Radchenko, Andrii, Dariusz Mikielewicz, Mykola Radchenko, Serhiy Forduy, Oleksandr Rizun, and Viktor Khaldobin. "Innovative combined in-cycle trigeneration technologies for food industries." E3S Web of Conferences 323 (2021): 00029. http://dx.doi.org/10.1051/e3sconf/202132300029.
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The majority of integrated energy systems (IES) for combined electricity, heat and refrigeration generation, or trigeneration, are based on gas engines. The fuel efficiency of gas engines are strictly influenced by intake air temperatures. Practically in all IES the absorption lithium-bromide chillers (ACh) are applied for conversing the heat removed from the engine into refrigeration in the form of chilled water. The peculiarity of trigeneration in food industries is the use of chilled water of about 12°C for technological needs instead of 7°C as typical for ACh. This leads to a considerable great potential of engine intake air deeper cooling not realized by ACh, that can be used by ejector chiller (ECh) as the low temperature stage of two-stage absorption-ejector chiller (AECh) to provide engine cyclic air deep cooling and enhancing engine fuel efficiency. To evaluate the effect of gas engine cyclic air cooling the data on fuel consumption and power output of gas engine JMS 420 GS-N.L were analyzed.
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PROF., GOPAL REDDY K. "PRODUCTION OF ELECTRICITY BY SOLAR STIRLING ENGINE." IJIERT - International Journal of Innovations in Engineering Research and Technology 4, no. 7 (July 20, 2017): 12–15. https://doi.org/10.5281/zenodo.1459092.
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<strong>The Stirling engine is both practically and theoretically a significant device,its practical virtue is simple,reliable and safe. The engine operates on a closed thermodynamic cycle,which is reversible. Today Stirling cycle - based systems are in commercial use as a heat pump,cryogenic refrigeration and air liquefaction. As a prime mover,Stirling cycles remain the subject of research and development efforts. A number of attempts have been made to build and improve the performance of Stirling engines. For successful operation of engine system with good efficiency,a careful design of heat exchangers,proper selection of drive mechanism and engine configuration is essential. Our Discussion indicates that a Stirling cycle engine working with relatively low temperature with air of helium as working fluid is potentially attractive engines of the future,especially solar - powered low - temperature differential Stirling engines with vertical,double acting,and gamma configuration. It is pollution free engine and use of any type of fuel characteristics and it shows a greater potential over any other type of engine existing today. This paper represents adetailed review of the past efforts taken for the development of the Stirling cycle engine and techniques used for engine analysis.</strong> <strong>https://www.ijiert.org/paper-details?paper_id=141063</strong>
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Mekhtiyev, A. D., V. V. Yugay, A. D. Alkina, Y. G. Neshina, and D. E. Kapanova. "Studying a low-temperature engine with external heat supply." Journal of Physics: Conference Series 1843, no. 1 (March 1, 2021): 012006. http://dx.doi.org/10.1088/1742-6596/1843/1/012006.
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Kaiser, Sascha, Markus Nickl, Christina Salpingidou, Zinon Vlahostergios, Stefan Donnerhack, and Hermann Klingels. "Investigations of the synergy of Composite Cycle and intercooled recuperation." Aeronautical Journal 122, no. 1252 (May 15, 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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Kaiser, Sascha, Markus Nickl, Christina Salpingidou, Zinon Vlahostergios, Stefan Donnerhack, and Hermann Klingels. "Investigations of the synergy of Composite Cycle and intercooled recuperation." Aeronautical Journal 122, no. 1252 (May 15, 2018): 869–88. https://doi.org/10.5281/zenodo.1489114.
Full textAbstract:
The 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 utilize closed volume combustion and high temperature capability due to instationary operation. The second is the Intercooled Recuperated engine that employs recuperators to utilize 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 piston system through a significant, efficiency-neutral weight decrease. Waste heat can be utilized 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 utilization 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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Avinash, Gangadhar Virale, and Tukaram Nitnaware Pravin. "EXPERIMENTAL ANALYSIS OF JACKET COOLING OF S I ENGINE AND STUDY OF OPERATING PARAMETERS AND EMISSIONS." International Journal of Advances in Engineering & Technology 10, no. 1 (July 24, 2020): 113–21. https://doi.org/10.5281/zenodo.3958630.
Full textAbstract:
<em>About 17-26% of input energy to the spark ignition engine is lost as heat energy though the engine. This heat energy is removed by means of jacket cooling water. The temperature of the engine is required to be maintained within an optimum range for proper operation of the engine. Very high temperature of the engine leads to increase in the emissions and friction power (losses). Low engine temperature leads to improper vaporization of the fuel and thus starting problems. So the engine temperature needs to be maintained at an optimum value. The effects on various operating parameters and emission characteristics have been studied with the variation in the Engine Temperature maintained by varying the temperature of cooling water. Operating parameters like Friction Power, Mechanical Efficiency, Brake Thermal Efficiency, Brake Specific Fuel Consumption, Brake Mean Effective Pressure, and Emission characteristics like NO<sub>x</sub>, CO, HC’s and Exhaust Gas Temperatures were observed and graphically represented. In this study it was attempted to deduce the temperature range of proper operation of the 3-cylinder Spark Ignited engine.</em>
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Murti, Prastowo, Ikhsan Setiawan, Jihan Zeinyuta Rosafira, Adhika Widyaparaga, Wijayanti Dwi Astuti, and Tetsushi Biwa. "Analysis of a standing wave thermoacoustic engine with multiple unit stages." International Journal of Renewable Energy Development 13, no. 4 (May 15, 2024): 708–15. http://dx.doi.org/10.61435/ijred.2024.60098.
Full textAbstract:
The thermoacoustic engine is an eco-friendly technology capable of harnessing solar and waste energy for electricity generation, in conjunction with a linear alternator, and can function as a heat pump. This engine type holds significant appeal due to its simplistic design, devoid of any mechanical moving components, comprising only a stack sandwiched between heat exchangers within a resonator. When the temperature gradient across the stack reaches the critical threshold (onset temperature), the working gas undergoes spontaneous oscillation. Typically, a high onset temperature is necessary to induce gas oscillation in a thermoacoustic engine due to viscous losses within the system. A method to lower the onset temperature by increasing the number of unit stages consisting of stacks and heat exchangers so that the engine can utilize low-grade thermal sources has been developed to overcome this challenge. However, this method has only been applied to traveling-wave thermoacoustic engines. Its application in standing-wave engines, which offer a more compact and straightforward structure, remains unexplored. This research aims to examine how the number of unit stages in a standing-wave thermoacoustic engine influences the onset temperature and acoustic field. The onset temperature is estimated using a fundamental hydrodynamics equation and the investigation of the acoustic field throughout the engine using DeltaEC software. Results showed that the strategic positioning of multiple unit stages is essential to achieve a low onset temperature. The minimum onset temperature, approximately 92°C, is obtained when three- or four-unit stages are installed. Additionally, increasing the number of unit stages does not affect the acoustic impedance and phase difference between pressure and velocity in the stack, while simultaneously enhancing both acoustic power output and thermal efficiency.
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Radchenko, Andrii, Mykola Radchenko, Andrii Konovalov, and 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.
Full textAbstract:
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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Liu, Yang, Yituan He, Cuijie Han, and 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, no. 1 (January 2019): 168781401881958. http://dx.doi.org/10.1177/1687814018819580.
Full textAbstract:
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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Amann, C. A. "Promises and Challenges of the Low-Heat-Rejection Diesel." Journal of Engineering for Gas Turbines and Power 110, no. 3 (July 1, 1988): 475–81. http://dx.doi.org/10.1115/1.3240145.
Full textAbstract:
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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Elagin, Mikhail Y., and Roman N. Khmelev. "Numerical simulation of the diesel engine starting considering air pre-heating in the intake system." Izvestiya MGTU MAMI 17, no. 3 (December 25, 2023): 209–16. http://dx.doi.org/10.17816/2074-0530-375320.
Full textAbstract:
BACKGROUND: Low temperature of the intake air is one of the reasons of difficult starting of a cold diesel engine in conditions of negative outside temperatures. For a reliable staring of a cold diesel engine, it is necessary to have the temperature at the end of the compression stroke higher than the fuel self-ignition temperature. As the temperature at the end of the compression stroke is defined, first, by the temperature at the end of the intake stroke, the mentioned condition can be satisfied with preliminary warming of the air entering in a cylinder.
 AIMS: The article is devoted to solving the task related to development of a mathematical model of a diesel engine taking into account air pre-heating in the intake system and ensuring simulation of the pre-starting mode, starting and operation of a diesel engine in conditions of low negative outside temperature.
 METHODS: The enhanced mathematical model of a diesel engine basing on heat mechanics (thermodynamics of opened systems) which reflects main features of an internal combustion engine (ICE) as the system transforming energy in time domain is proposed in the article. The mathematical model’s equation system is based on laws of conservation of energy and mass, solid bodies’ motion equation and includes differential equations of changing of temperature and density of the working body in a cylinder, in the intake system and in the ICE’s crankcase, the ideal gas state equation as well as differential equations of changing of rotation velocity and rotation angle of an engine’s crankshaft.
 RESULTS: The mathematical model was tried out on the example of the 1Ch9.5/8.0 multi-purposed air-cooled diesel engine. The results of simulation of the pre-starting mode, starting and operation of the diesel engine taking into account air pre-heating in the intake system are presented in the article.
 CONCLUSIONS: Implementation of air pre-heating at the intake in the design of diesel engines is the most effective way of ensure starting of the engines at low negative outside temperature. The obtained results help to develop recommendations of choosing power and operation modes of pre-heating devices for ensuring starting and operation of diesel engines in conditions of low negative outside temperatures.
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Yang, Zongming, Roman Radchenko, Mykola Radchenko, Andrii Radchenko, and Victoria Kornienko. "Cooling Potential of Ship Engine Intake Air Cooling and Its Realization on the Route Line." Sustainability 14, no. 22 (November 14, 2022): 15058. http://dx.doi.org/10.3390/su142215058.
Full textAbstract:
A fuel efficiency of a ship engine increases with cooling inlet air. This might be performed by the chillers, which transform the heat of engine exhaust gas and scavenge air for refrigeration. The effect gained due to cooling depends on the intake air temperature drop and the time of engine operation at decreased intake air temperature. Thus, the cooling degree hour (CDH) number, calculated as air temperature depression multiplied by the duration of engine operation at reduced intake air temperature, is used as a primary criterion to estimate the engine fuel efficiency enhancement due to intake air cooling over the ship routes. The engine intake air cooling potential is limited by its value, available according to engine exhaust heat and the efficiency of heat conversion to refrigeration in the chiller, evaluated by the coefficient of performance (COP). Therefore, it should be determined by comparing both the needed and available values of CDH. The ejector chiller (ECh) was chosen for engine exhaust gas heat recovery to refrigeration as the simplest and cheapest, although it has a relatively low COP of about 0.3 to 0.35. However, the ECh generally consists of heat exchanges which are mostly adapted to be placed in free spaces and can be mounted on the transverse and board side bulkheads in the ship engine room. The values of sucked air temperature depression and engine fuel consumption reduction at varying temperatures and humidity of ambient air on the route were evaluated.
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Nik Kechik Mujahidah Nik Abdul Rahman, Syamimi Saadon, and Mohd Hasrizam Che Man. "Heat Transfer Enhancement of Biomass Based Stirling Engine." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 100, no. 1 (December 6, 2022): 1–10. http://dx.doi.org/10.37934/arfmts.100.1.110.
Full textAbstract:
Stirling engine as an external combustion engine with high efficiencies and able to use any types of heat source is the best candidate to recover waste heat of the exhausted gas by converting it into power. Thus, in this study Stirling engine was introduced to evaluate the possibility of recovering waste heat from biomass to produce power. For this reason, Computational Fluid Dynamic (CFD) simulation test was performed to design an initial computational model of Stirling engine for low temperature heat waste recovery. The CFD model was validated with the experiment model and shows 6.11% of average deviation. This result proves that the computational model can be further used to evaluate the performance of Stirling engine as waste heat recovery of biomass-based industrial boilers for low-grade temperature heat source.
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Merzlikin, V. G., A. R. Makarov, S. V. Smirnov, A. V. Kostukov, and Marcos Ojeda Gutierrez. "Low-cost, eco-friendly diesel with a thermally insulated combustion chamber." Traktory i sel hozmashiny 85, no. 5 (October 15, 2018): 56–68. http://dx.doi.org/10.17816/0321-4443-66419.
Full textAbstract:
The performance of a diesel engine has been studied using well-known types of ceramic thermal insulating HIC or thermal barrier TBC coatings. This problem is relevant for a diesel engine with low thermal losses of the combustion chamber, in which the intense radiant component (in the near-IR range) reaches ∼ 50 % of the total heat flow. In this paper, the authors continued to study these coatings, but as translucent (SHICs or STBCs) with bulk absorption of penetrating radiant energy. The spectrophotometric modeling of the optical parameters of these coatings made it possible to estimate the characteristics of the temperature field being formed with a reduced near-surface temperature gradient (compared to opaque coatings), causing a significant decrease in heat loss through the heat-insulated piston. A translucent STBC coating based on partially stabilized zirconia (PSZ ceramics ZrO2 + 8 % Y2O3) was chosen, determining the formation of the optimum temperature profile in the piston head. For bench testing was used experimental single-cylinder tractor diesel. With a rotation frequency of n > 2800 1/min, the heat loss did not exceed 0,2 MW/m2 through the bottom of the piston with the heat-shielding layer. The tests performed showed a lower specific fuel consumption of ∼ 2-3 % in comparison with the combustion chamber of a diesel engine with an uncoated ceramic piston. At the same time, torque and effective power increased by ∼ 2-5 %.
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Радченко, Микола Іванович, Дмитро Вікторович Коновалов, Чжан Цян, Лю Шаоцзюнь, Луо Зевей та Джі Ран. "ОХОЛОДЖЕННЯ НАДДУВНОГО ПОВІТРЯ ГОЛОВНОГО СУДНОВОГО ДВИГУНА ЕЖЕКТОРНОЮ ХОЛОДИЛЬНОЮ МАШИНОЮ В ЕКВАТОРІАЛЬНИХ ШИРОТАХ". Aerospace technic and technology, № 2 (27 квітня 2020): 24–29. http://dx.doi.org/10.32620/aktt.2020.2.04.
Full textAbstract:
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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Вахрамеев, Д. А., И. А. Дерюшев, Е. А. Потапов, А. А. Мартюшев, and Ф. Р. Арсланов. "JUSTIFICATION OF AIR CHARGE PARAMETERS AT DIESEL START-UP UNDER LOW TEMPERATURES." Bulletin of Izhevsk State Agricultural Academy, no. 2(74) (June 30, 2023): 64–70. http://dx.doi.org/10.48012/1817-5457_2023_2_64-70.
Full textAbstract:
Существенным недостатком при эксплуатации дизельных двигателей является затрудненный пуск в зимний период. Целью работы было создание в цилиндрах дизельного двигателя топливовоздушной смеси с показателями, обеспечивающими его гарантированный пуск в условиях низких температур. Для обеспечения точности теоретических расчетов температуры топливовоздушной смеси предложено ввести поправочный коэффициент К, учитывающий пониженное значение фактической компрессии в процессе пуска дизеля. На базе установленного на открытой площадке стенда проведена серия испытаний по исследованию эффективности применения разработанного теплового аккумулятора для предпусковой подготовки двигателя Д-243. В работе представлены результаты экспериментальных исследований изменения компрессии в цилиндрах дизельного двигателя при пуске в зависимости от его температуры, изменение предстартовых температурных параметров дизеля в результате подогрева охлаждающей жидкости, моторного масла и топлива путем применения энергии теплового аккумулятора. Предлагаемая конструкция теплового аккумулятора показала достаточно высокую эффективность в течение межсменного хранения техники. Температура хранения рабочих жидкостей в тепловом аккумуляторе за 15 часов снижалась с +90 до +54 ℃. При начальной пусковой температуре двигателя -15 ℃ и подаче в его системы охлаждающей жидкости и моторного масла из теплового аккумулятора уже через 3 минуты температура головки цилиндров составляет +18 ℃, а температура моторного масла +45 ℃, что полностью обеспечивает гарантированный процесс пуска дизельного двигателя. Установка в систему воздухоподачи дизельного двигателя пусковой турбины позволит компенсировать снижение давления воздушного заряда при пуске. Питание турбины должно осуществляться от бортовой сети трактора. Diesel engines have a significant drawback – a difficult start-up when operating them in the winter season. The aim of the work was to create a fuel-air mixture in the cylinders of a diesel engine with indicators that ensure its guaranteed start-up at low temperatures. To ensure the accuracy of theoretical calculations of the temperature of the fuel-air mixture, it is proposed to introduce a correction factor "K", taking into account the reduced value of the actual compression during the diesel start-up process. A series of tests was carried out to study the effectiveness of the use of the developed thermal accumulator for pre-launch preparation of the D-243 engine on the basis of the open area stand. The paper presents the results of experimental studies of changes in compression in the cylinders of a diesel engine during start-up depending on its temperature, a change in the pre-start temperature parameters of a diesel engine as a result of heating the coolant, engine oil and fuel by using the energy of a thermal accumulator. The proposed design of the heat accumulator showed a fairly high efficiency during the inter-shift storage of equipment. The temperature of storage of working fluids in a thermal accumulator decreased from +90 ℃ to +54 ℃ within 15 hours. With an initial starting temperature of the engine of -15 ℃ and the supply of coolant and engine oil from the heat accumulator to its systems, after 3 minutes the temperature of the cylinder head is +18 ℃, and the temperature of the engine oil is +45 ℃, which fully ensures the guaranteed process of starting the diesel engine. Installing a starting turbine in the air supply system of a diesel engine will make it possible to compensate for the decrease in air charge pressure during start-up. The turbine must be powered from the on-board network of the tractor.
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Lyu, Long. "Modeling and Optimization of Ship Waste Heat Utilization System Based on Genetic Algorithm and Sensing." International Transactions on Electrical Energy Systems 2022 (August 29, 2022): 1–8. http://dx.doi.org/10.1155/2022/9917212.
Full textAbstract:
In order to solve the optimization problem of ship waste heat utilization system, the modeling and optimization method of ship waste heat utilization system based on genetic algorithm and sensing is proposed. The 6S50ME-C8.2 volume method model was established based on Matlab/Simulink simulation platform. According to the test data of the 6S50ME-C8.2 diesel engine, the simulation value is very close to the test value, which verifies the accuracy of the simulation model. The experimental results show that the thermal efficiency of high-power medium and low-speed two-stroke diesel engines is high, the exhaust temperature of the main engine is generally maintained at about 230°C, and the energy content of exhaust gas is relatively low. If no other measures are taken, the waste gas is directly channeled into the waste heat boiler, which cannot effectively recover the heat in the waste gas. Conclusion. The model can well simulate the actual working condition of the diesel engine, and the exhaust temperature has reached 298°C. The energy quality of waste gas at the inlet of the waste heat boiler is improved to meet the requirements of the waste heat recovery system.
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Allmägi, Roland, Risto Ilves, and Jüri Olt. "COMPREHENSIVE REVIEW OF INNOVATION IN PISTON ENGINE AND LOW TEMPERATURE COMBUSTION TECHNOLOGIES." Transport 39, no. 1 (May 21, 2024): 86–113. http://dx.doi.org/10.3846/transport.2024.21333.
Full textAbstract:
Global transport today is mainly powered by the Internal Combustion Engine (ICE) and throughout its century and a half of development it has become considerably more efficient and cleaner. Future prospects of the ICE rely on the scientific work conducted today to keep this trend of higher efficiency and cleaner emissions in new engines going. The aim of this article is to give a comprehensive review of development directions in novel piston engine designs, which seek to overcome the drawbacks of the ubiquitous 4-stroke piston engine. One of the directions of development is devoted to improving the mechanisms and the general layout of the piston engine to reduce losses within the engine. Research teams working with alternative engine work cycles like the 5- and 6-stroke engine and technologies for extracting waste heat seek to reduce thermal losses while novel layouts of valve trains and crank assemblies claim to significantly improve the mechanical and Volumetric Efficiency (VE) of piston engines. These novel ideas include camless or Variable Valve Action (VVA) and engines with Variable Compression Ratio (VCR) or opposed pistons. One alternative approach could also be to totally redesign the reciprocating mechanism by replacing the piston with some other device or mechanism. Additional scientific work is investigating Low Temperature Combustion (LTC) technologies such as Turbulent Jet Ignition (TJI) and Homogeneous Charge Compression Ignition (HCCI) and its derivatives like Premixed Charge Compression Ignition (PCCI) and Reactivity Controlled Compression Ignition (RCCI) that have shown improvements in thermal and fuel conversion efficiency while also significantly reducing harmful emissions. These combustion strategies also open the path to alternative fuels. The contemporary work in the combustion engine fields of research entail technical solutions from the past that have received a modern approach or are a completely novel idea. Nonetheless, all research teams work with the common goal to make the piston engine a highly efficient and environmentally friendly device that will continue to power our transport and industry for years to come. For this, solutions must be found to overcome the mechanical limitations of the traditional layout of the piston engine. Similarly various improvements in combustion technology are needed that implement state of the art technology to improve combustion characteristics and reduce harmful emissions.
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Smith, James E., and Randy Churchill. "A Concept Review of Low-Heat-Rejection Engines." Applied Mechanics Reviews 42, no. 3 (March 1, 1989): 71–90. http://dx.doi.org/10.1115/1.3152422.
Full textAbstract:
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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Lottmann, Matthias, Zachary de Rouyan, Linda Hasanovich, Steven Middleton, Michael Nicol-Seto, Connor Speer, and David Nobes. "Development of a 100-Watt-Scale Beta-Type Low Temperature Difference Stirling Engine Prototype." E3S Web of Conferences 313 (2021): 08004. http://dx.doi.org/10.1051/e3sconf/202131308004.
Full textAbstract:
This paper documents the ongoing design process of a Stirling engine prototype for a source temperature of 95 °C, aiming to achieve shaft power on the order of 100 Watts. The engine will serve to produce experimental data for the validation of a numerical low temperature Stirling model. The higher-level motivation is to assess the technical and economical potential of producing power from abundant sources of low temperature heat by using Stirling engines. Design decisions are governed by the goals of minimizing energy losses and maximizing the variability of operating points through variable heat exchanger geometry, compression ratio and charge pressure. The resulting design is a beta engine with a total gas volume around 100 liters. It features displacer and power pistons in a combined cylindrical working space and a mechanism using pivoting links similar to a bellcrank. The stroke of the power piston is adjustable while maintaining a constant top dead center position. A component critical for friction is the power piston seal, for which a low friction rolling seal and a conventional sliding seal were considered. As of June 2021, the development is at an advanced state and the first set of components are entering production.
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Радченко, Андрій Миколайович, Дмитро Вікторович Коновалов, Іван Володимирович Калініченко, Чен Нінь та Хан Баочен. "ОХОЛОДЖЕННЯ НАДДУВНОГО ПОВІТРЯ ГОЛОВНОГО СУДНОВОГО ДВИГУНА АБСОРБЦІЙНОЮ БРОМИСТОЛІТІЄВОЮ ХОЛОДИЛЬНОЮ МАШИНОЮ В ЕКВАТОРІАЛЬНИХ ШИРОТАХ". Aerospace technic and technology, № 2 (27 квітня 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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TAKEUCHI, Makoto, and 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, and Abhijit Date. "Development of Low Temperature Heat Engine for Water Pumping Application." Energy Procedia 110 (March 2017): 292–97. http://dx.doi.org/10.1016/j.egypro.2017.03.142.
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Gonsalves, Sheetal, and Swapna Gabbur. "Enhancing convective heat transfer in engine oil: a comparative study of various nanoparticles." Structural Integrity and Life 25, Special Issue A (March 16, 2025): S9—S15. https://doi.org/10.69644/ivk-2025-sia-0009.
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The study explores heat transfer properties of five different nanofluid flows past an oil cooling system. The numerical investigation is carried out by developing mathematical model by utilising nanofluids volume fraction in engine oil based nanofluid containing solid particles of molybdenum disulfide (MoS2), aluminium oxide (Al2O3), titanium oxide (TiO2), graphene oxide (GO), and copper (Cu). The system of PDE is converted to ODE using appropriate similarity transformations and then solved by employing the FEM. The influence of different nanoparticles on temperature and velocity distributions are analysed graphically. Additionally, the impact of various nanoparticles for the key parameters on the rate of heat transfer and coefficient of skin friction are presented in tabular form. The GO nanoparticles suspended in engine oil exhibit the comparatively lowest temperature and skin friction coefficient, and highest heat transfer capabilities. It may therefore be considered as the best lubricant for engines as it offers low friction and temperature, potentially extending the engine component's lifespan.
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Yin, Yuwei. "Study on the Circulation Efficiency of Different Nonideal Gases." Highlights in Science, Engineering and Technology 5 (July 7, 2022): 75–85. http://dx.doi.org/10.54097/hset.v5i.726.
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The thermodynamic properties of two kinds of representative non-ideal real gases van der Waals gas and Onnes gas are expounded and discussed by common thermodynamic methods, and the specific expressions of heat engine efficiency based on Carnot cycle, Stirling cycle and Otto cycle with these two real gases as working fluids are derived through theoretical derivation and calculation. On this basis, the variation rules of various thermal efficiency corresponding to heat engine with cycle parameters (such as high-temperature heat source temperature T1, low-temperature heat source temperature T2, the isovolumetric molar heat capacity of gas, initial volume V in the cycle process, gas volume expansion ratio r) are analyzed, and the general rules which are helpful to improve the efficiency of heat engine are found. This work will provide some theoretical reference for the optimal design of the actual operating conditions of the heat engine.
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Lebedevas, Sergejus, and Tomas Čepaitis. "Complex Use of the Main Marine Diesel Engine High- and Low-Temperature Waste Heat in the Organic Rankine Cycle." Journal of Marine Science and Engineering 12, no. 3 (March 21, 2024): 521. http://dx.doi.org/10.3390/jmse12030521.
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The decarbonization problem of maritime transport and new restrictions on CO2 emissions (MARPOL Annex VI Chapter 4, COM (2021)562) have prompted the development and practical implementation of new decarbonization solutions. One of them, along with the use of renewable fuels, is the waste heat recovery of secondary heat sources from a ship’s main engine, whose energy potential reaches 45–55%. The organic Rankine cycle (ORC), which uses low-boiling organic working fluids, is considered one of the most promising and energy-efficient solutions for ship conditions. However, there remains uncertainty when choosing a rational cycle configuration, taking into account the energy consumption efficiency indicators of various low-temperature (cylinder cooling jacket and scavenging air cooling) and high-temperature (exhaust gas) secondary heat source combinations while the engine operates within the operational load range. It is also rational, especially at the initial stage, to evaluate possible constraints of ship technological systems for ORC implementation on the ship. The numerical investigation of these practical aspects of ORC applicability was conducted with widely used marine medium-speed diesel engines, such as the Wartsila 12V46F. Comprehensive waste heat recovery of all secondary heat sources in ORC provides a potential increase in the energy efficiency of the main engine by 13.5% to 21% in the engine load range of 100% to 25% of nominal power, while individual heat sources only achieve 3% to 8%. The average increase in energy efficiency over the operating cycle according to test cycles for the type approval engines ranges from 8% to 15% compared to 3% to 6.5%. From a practical implementation perspective, the most attractive potential for energy recovery is from the scavenging air cooling system, which, both separately (5% compared to 6.5% during the engine’s operating cycle) and in conjunction with other WHR sources, approaches the highest level of exhaust gas potential. The choice of a rational ORC structure for WHR composition allowed for achieving a waste heat recovery system energy efficiency coefficient of 15%. Based on the studied experimental and analytical relationships between the ORC (generated mechanical energy) energy performance (Pturb) and the technological constraints of shipboard systems (Gw), ranges for the use of secondary heat sources in diesel operational characteristic modes have been identified according to technological limits.
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DOLGUSHIN, А. А., A. F. KURNOSOV, and R. V. CHERNUKHIN. "HEAT EXCHANGE OF THE TRANSMISSION UNITS OF TRUCK ENGINE." Tekhnicheskiy servis mashin 62, no. 2 (June 21, 2024): 65–70. http://dx.doi.org/10.22314/2618-8287-2024-62-2-65-70.
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A significant share of goods in agriculture are transported by road at low ambient temperatures. Changing the properties of oils in these conditions significantly reduces the efficiency of the machines and requires additional measures for the thermal preparation of the units. (Research purpose) The research purpose is identifying heat flows between the engine and the transmission units of a truck and their effect on the thermal mode of the middle and rear axles. (Materials and methods) We performed experimental studies on a KamAZ 65115 car. Convective heat flows and heat transfer through thermal conductivity in the "engine-transmission units" system, as well as their effect on the thermal mode of transmission gearboxes, were studied. (Results and discussion) The effect of the engine on the thermal mode of the gearbox was established: the oil temperature rise was five degrees; the oil temperature stabilization time was 70-74 minutes. The effect of the engine on the thermal mode of the middle and rear axles was not revealed. It was shown that the main heat flows causing the gearbox to heat up are the air flows washing the block and crankcase of the engine. An increase in the air flow velocity to 25 meters per second leads to a decrease in temperature near the engine block by 2.5 percent to 278 kelvin, and near the crankcase by 3 percent to 253 kelvin. (Conclusions) Engine temperature has a significant effect only on the temperature of the gearbox. At air speeds above 10 meters per second, stabilization of transmission temperature is observed. Heat flows that cause additional heating of the gearbox are formed on the side surfaces of the cylinder block and the engine oil sump.
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Yang, Lining, Xiaoxia Sun, and Tao Zhang. "Performance Simulation Analysis of Modular Heat Dissipation Unit." Journal of Physics: Conference Series 2160, no. 1 (January 1, 2022): 012063. http://dx.doi.org/10.1088/1742-6596/2160/1/012063.
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Abstract In this paper, GT suite software is used to model the cooling system of military special vehicles with multiple power sources. The power drive system is composed of main engine, auxiliary engine and four hub motors. By constructing modular cooling unit, the volume of radiator and the layout of cooling unit are changed. While the total volume of radiator is unchanged, the cooling capacity of cooling system is improved. Firstly, the problem is simplified and modeled by high-temperature and low-temperature double circuit. The main engine with power of 600kW and auxiliary engine with power of 200kW are combined into a high-temperature circuit. The water temperature of the circuit is higher, about 90 ºC; Four hub motors with power of 440kw and their electrical components are combined into a low temperature circuit. The water temperature of this circuit is about 60 ºC. By modifying the volume, layout and number of radiators, the temperature of the dual circuit is analyzed, and it is found that when the total radiator volume remains the same, the cooling effect of the multi-radiator layout is better.
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Kropiwnicki, Jacek, and Aleksandra Szewczyk. "Stirling Engines Powered by Renewable Energy Sources." Applied Mechanics and Materials 831 (April 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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Faităr, C., D. Jugănaru, N. Buzbuchi, L.-C. Stan, and V. Poenaru. "Study of the functional parameters of main engine turbocharger for a tanker ship." IOP Conference Series: Materials Science and Engineering 1182, no. 1 (October 1, 2021): 012024. http://dx.doi.org/10.1088/1757-899x/1182/1/012024.
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Abstract To correctly understand the requirements of a system, we must first study its schematics. In the case of energy systems, they require a detailed diagram of energy performance. Heat losses can be classified into high-temperature losses, medium-temperature and low-temperature losses. On board ships with low-speed propulsion engines, heat recovery systems operate in the range of 100-400 °C. Many residual energy recovery systems from internal combustion engines are under development: for example the MAN WHR development program for Tier III technologies. In this paper, I will treat both theoretical calculation elements and real elements of the operation of the turbocharging system, for the main reference engine. I chose to treat this system because it is a main subassembly for the engine, in terms of operation and thus its efficiency. In the theoretical calculation, I will start from the initial calculation data and I will expose the geometric and functional parameters of the turbocharger. The exhaust gases up to a temperature of 650 °C passes continuously through the turbine and heat its components, without its system of contraction cooling. In particular, the shaft bearing must withstand high operating temperatures without ever breaking the lubrication device. On the compressor side, the air is heated to over 200 °C. High temperatures lead to extreme thermal loads of the material in many locations. Speeds are extremely high: METxxSE turbochargers, as in figure 1, run at speeds between 10000 and 35000 rpm, depending on size. In this respect, the tangential speeds of 560 m / s and even more are reached at the compressor turbine, which rises to 1.7 times the speed of sound or 2000 km / h. The efficiency of the operation of the turbocharger system related to the main propulsion engine depends on the internal processes that take place in its operation, and also on the environmental conditions. In this way, the direction of processing on the installation is dictated by the engine load, taking into account the extreme situations, corresponding to the operation of the ship in special conditions (overload, tropical temperature, arctic temperature etc.).