Showing papers on "Thermal efficiency published in 2012"
TL;DR: In this paper, the authors systematically review the engine knock phenomenon, including the mechanisms, influencing factors, consequences and detection methods, and propose some new suggestions on the weakness in the researches of knocking combustion.
363 citations
TL;DR: In this article, a thermal energy storage system, consisting of a packed bed of rocks as storing material and air as high-temperature heat transfer fluid, is analyzed for concentrated solar power (CSP) applications.
304 citations
TL;DR: In this paper, an organic rankine cycle (ORC) system used in the internal combustion engine (ICE) exhaust heat recovery was proposed and techno-economically analyzed based on various working fluids.
242 citations
TL;DR: A comprehensive overview of the field of gas turbine coatings can be found in this article, where the authors present a detailed overview of methods of application and characterization, degradation mechanisms and indicative future directions which are of use to a practicing industrial engineer.
232 citations
TL;DR: In this article, the performance, combustion and emission characteristics of diesel engine fueled by biodiesel at partial load conditions were investigated, and the results showed that biodiesel/blend fuels have significant impacts on the engine's brake specific fuel consumption (BSFC) and brake thermal efficiency (BTE).
225 citations
TL;DR: In this paper, the authors proposed a novel selection scheme of energy efficient distillation technologies, with a special focus on heat pumps, which considers as the main selection criteria the type of separation tasks, product flow and specifications, operating pressure, difference in boiling points, reboiler duty and its temperature level.
217 citations
TL;DR: In this paper, a typical tubular vertical recuperative heat exchanger is designed in order to integrate into the gas turbine cycle as an air preheater for thermal efficiency improvement, and the final optimal solution has been selected using three decision-making approaches including the fuzzy Bellman-Zadeh, LINMAP and TOPSIS methods.
199 citations
TL;DR: In this article, the effect of injection pressure and timing on performance, emission and the combustion characteristics of a single cylinder, four-stroke direct injection diesel engine at a constant speed of 1500rpm was investigated.
Abstract: Due to the depleting amount of petroleum reserves and the increasing awareness on environmental concerns, biodiesel has become one of the most demanding and promising substitutes for the petroleum based fossil fuels. In this study, the biodiesel derived from waste cooking oil through the transesterification process was optimized using Response Surface Methodology. The biodiesel derived under optimum conditions was used for investigating the effect of injection pressure and timing on performance, emission and the combustion characteristics of single cylinder, four-stroke direct injection diesel engine at a constant speed of 1500 rpm. On varying the injection pressure and timing, it was found that the combined effect of higher injection pressure of 280 bar and an advanced injection timing of 25.5°bTDC had significant improvement in the brake thermal efficiency, cylinder gas pressure and heat release rate. Reduction in nitric oxide (NO) and smoke emission was also observed.
170 citations
TL;DR: In this article, a comparison and optimization of 8 mostly-applied organic working fluids for ORC-based combined heat and power (CHP) systems with organic Rankine cycle (ORC) is presented.
147 citations
TL;DR: In this article, a dual-loop organic Rankine cycle (ORC) was used to harness the wasted heat from an internal combustion engine, and the performance of the combined engine-ORC system was evaluated.
145 citations
TL;DR: In this paper, a single cylinder diesel engine was modified to operate as a biogas operated spark ignition engine and the performance, emission and combustion characteristics with different compression ratios are compared.
TL;DR: In this paper, the performance of two different pre-commercial MD desalination modules developed by the Singaporean enterprise Keppel Seghers tested under real conditions intermittently for at least 2400h during two years, directly coupled with a static collector's solar field.
TL;DR: In this article, the effect of syngas on the performance, combustion and emission characteristics of a diesel engine was studied at different loads, and three different volumetric compositions were examined in the diesel engine under dual fuel modes.
TL;DR: In this paper, a new combined cooling, heating and power (CCHP) system was proposed to produce cooling output, heating output and power output simultaneously by combining a Brayton cycle and a transcritical CO2 refrigeration cycle with ejector-expansion device.
TL;DR: In this article, the authors studied the energy, economic and environmental implications of using complex small scale trigeneration energy conversion systems, starting with the results of an intensive theoretical and experimental research activity, and concluded that these systems, in comparison with conventional system, based on separate energy production, can guarantee a primary energy saving up to 28% and a reduction of equivalent CO 2 emissions up to 36%.
TL;DR: In this article, the effect of adding small amounts of hydrogen to gasoline-air mixtures on the performance and exhaust emission characteristics of a spark ignition engine was investigated, including thermal efficiency, specific fuel consumption, cyclic variations of the IMEP, and emissions of CO, NO and unburned hydrocarbons.
TL;DR: In this paper, the energy efficiency of an updated ORC (organic Rankine cycle) was investigated at different heat source temperatures of about 100, 90, 80, and 70°C.
TL;DR: In this paper, a theoretical study is conducted to investigate the potential improvement of the overall efficiency of a heavy-duty truck diesel engine equipped with a Rankine bottoming cycle for recovering heat from the exhaust gas.
TL;DR: In this article, a design method for ORCs is proposed to fully couple the ORC with the heat source, which is characterized by the mass flow rate, inlet and outlet heat carrier fluid temperatures.
TL;DR: In this article, the authors performed a comprehensive experimental characterization of a state-of-the-art porous media combustion in terms of thermal efficiency and pollutant emissions and assessed its operating limits.
TL;DR: In this article, the use of neat cashew nut shell oil (CSNO) as a fuel in direct injection diesel engine suffers from the problems of incomplete combustion and low brake thermal efficiency due to high viscosity.
TL;DR: In this paper, the impact of ethanol addition on combustion characteristics such as combustion duration, ignition delay and emissions levels from diesel engines fuelled with blends of ethanol, diesel and jatropha methyl ester (JME) through port injection is investigated in order to determine its effect fuel viscosity reduction on diesel engine performance.
TL;DR: In this paper, a single-cylinder, four-stroke, direct-injection, diesel engine operated on methyl esters of waste fried oil blended with mineral diesel was considered as the baseline data.
TL;DR: In this paper, a combined heat and power (CHP) biomass bubbling fluidized bed gasification unit coupled with an internal combustion engine (ICE) was evaluated using a comprehensive mathematical model based on the Aspen Plus® process simulator.
TL;DR: In this paper, the effect of oxygen enriched air was tested for a diesel-biogas dual fuel engine, and the operation and performance characteristics, such as thermal efficiency, pollutant emissions and combustion parameters were determined.
Abstract: The effect of oxygen enriched air was tested for a diesel-biogas dual fuel engine. The operation and performance characteristics, such as thermal efficiency, pollutant emissions and combustion parameters were determined. Experiments have been carried out with a stationary compression ignition (CI) engine coupled with a generator in dual mode using a typical biogas composition of 60 vol. %CH4 and 40% vol. %CO2. For every engine load evaluated, the oxygen concentration in the intake air engine was varied from 21% to 27% O2 v/v. Ignition delay time and methane emissions were decreased when using oxygen enriched air with respect to normal air (21%O2), whereas the thermal efficiency was increased.
TL;DR: In this paper, the authors presented some experimental investigations on dual fuel operation of a 4 cylinder (turbocharged and intercooled) 62.5kW gen-set diesel engine with hydrogen, liquefied petroleum gas (LPG) and mixture of LPG and hydrogen as secondary fuels.
TL;DR: In this article, a reaction controlled compression ignition (RCCI) operation in a light-duty multi-cylinder engine at three operating points was investigated. And the results showed that with the new piston bowl profile and an optimized injection schedule, RCCI brake thermal efficiency was increased from 37% with the stock EURO IV configuration, to 40% at the 2,600 rev/min, 6.9 bar BMEP condition, and NOx and PM emissions targets were met without the need for exhaust after-treatment.
Abstract: Reactivity Controlled Compression Ignition (RCCI) is an engine combustion strategy that that produces low NO{sub x} and PM emissions with high thermal efficiency. Previous RCCI research has been investigated in single-cylinder heavy-duty engines. The current study investigates RCCI operation in a light-duty multi-cylinder engine at 3 operating points. These operating points were chosen to cover a range of conditions seen in the US EPA light-duty FTP test. The operating points were chosen by the Ad Hoc working group to simulate operation in the FTP test. The fueling strategy for the engine experiments consisted of in-cylinder fuel blending using port fuel-injection (PFI) of gasoline and early-cycle, direct-injection (DI) of diesel fuel. At these 3 points, the stock engine configuration is compared to operation with both the original equipment manufacturer (OEM) and custom machined pistons designed for RCCI operation. The pistons were designed with assistance from the KIVA 3V computational fluid dynamics (CFD) code. By using a genetic algorithm optimization, in conjunction with KIVA, the piston bowl profile was optimized for dedicated RCCI operation to reduce unburned fuel emissions and piston bowl surface area. By reducing these parameters, the thermal efficiency of the engine was improved while maintaining low NOx and PMmore » emissions. Results show that with the new piston bowl profile and an optimized injection schedule, RCCI brake thermal efficiency was increased from 37%, with the stock EURO IV configuration, to 40% at the 2,600 rev/min, 6.9 bar BMEP condition, and NOx and PM emissions targets were met without the need for exhaust after-treatment.« less
TL;DR: In this paper, the valuation of waste fish fat by pyrolysis technique with the presence of catalyst to produce biofuel for diesel engines is discussed and a small quantity of diesel with biofuel is added to diesel engine to reduce NOx emissions.
Patent•
18 May 2012TL;DR: In this paper, a working medium for heat cycle comprising 1-chloro-2,3, 3,3-tetrafluoropropene and a mineral oil is employed for a heat cycle system.
Abstract: To provide a working medium for heat cycle, of which combustibility is suppressed, which has less influence over the ozone layer, which has less influence over global warming and which provides a heat cycle system excellent in the cycle performance (efficiency and capacity), and a heat cycle system, of which the safety is secured, and which is excellent in the cycle performance (efficiency and capacity). A working medium for heat cycle comprising 1-chloro-2,3,3,3-tetrafluoropropene and a mineral oil is employed for a heat cycle system (such as a Rankine cycle system, a heat pump cycle system, a refrigerating cycle system 10 or a heat transport system).
TL;DR: In this paper, a 330MWth integral nuclear reactor is considered as a potential candidate for applying the S-CO2 Brayton cycle and advantages and disadvantages of the proposed system are discussed in detail.