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Showing papers on "Thermal efficiency published in 2013"


Journal ArticleDOI
TL;DR: In this paper, a review of the history of internal combustion engine exhaust waste heat recovery focusing on organic Rankine cycles is presented, with a focus on the selection of the cycle expander and working fluid, since they are regarded as having the largest impact on system performance.

404 citations


Journal ArticleDOI
TL;DR: In this paper, a thermal management system equipped with heat pipes was designed according to the heat generated character of power batteries to increase the cycle time of power battery and decrease the overall cost of electric vehicles.

370 citations


Journal ArticleDOI
01 Sep 2013-Fuel
TL;DR: In this paper, a single cylinder research engine was used to experimentally determine the effects of fuel injection strategies and injection timings on engine combustion, performance and emission characteristics, and the experiments were conducted at constant speed (2500-rpm) with two FIPs (500 and 1000 bars respectively) and different start of injection (SOI) timings.

366 citations


Journal ArticleDOI
TL;DR: In this paper, a comprehensive review on the impact of potential biodiesel feedstocks (edible and non-edible) on engine performance and exhaust emissions including details of engine and operating condition is presented.
Abstract: Global energy demand is increasing due to the population growth and industrialization. In order to fulfill the energy demand with considering global concern, it is necessary to find out alternative fuel sources. Biodiesel is one of the best choices because of its immense potential to be part of energy mix in the near future as well as the capability of reducing greenhouse gas emissions. This paper aims to provide information to the engineers, industrialists and researchers who are interested on biodiesel. The paper presents a comprehensive review on the impact of potential biodiesel feedstocks (edible and non-edible) on engine performance and exhaust emissions including details of engine and operating condition. A large number of literatures from highly rated journals in scientific indexes are reviewed including the most recent publications. Most of the authors showed that using biodiesel from various feedstocks in diesel engines slightly lowered brake power and brake thermal efficiency but increases BSFC than diesel fuel. It was also reported that biodiesel significantly reduced the PM, HC, CO and CO 2 emissions but gives slightly higher NOx emissions. It was shown that NOx can be reduced by some approaches such as blending with additives and EGR technique. The study concluded that biodiesel can be used in compression ignition engine with no or minor engine modification. Finally biodiesel can be used as a substitute of diesel fuel to fulfill the energy demand, reduce dependency on fossil fuel as well as the exhaust emissions of the engine.

268 citations


Journal ArticleDOI
Guopeng Yu1, Gequn Shu1, Hua Tian1, Haiqiao Wei1, Lina Liu1 
01 Mar 2013-Energy
TL;DR: In this paper, a simulation model based on an actual organic rankine cycle (ORC) bottoming system of a diesel engine is presented to recover waste heat both from engine exhaust gas and jacket water using R245fa as working fluid.

237 citations


Journal ArticleDOI
TL;DR: A comprehensive review of various fuel injection strategies viz varying injection pressure, injection rate shapes, injection timing and split/multiple injections for engine performance improvement and emissions control is presented in this paper.
Abstract: The call for reduction in pollution has been mandated by government′s policies worldwide. This challenges the engine manufacturer to strike an optimum between engine performance and emissions. However with growing technology in the field of fuel injection equipment, the task has become realizable. For past few years it has been the hot topic to improve combustion and emissions of compression ignition engines through optimizing the fuel injection strategies. Choosing between various injection strategies are potentially effective techniques to reduce emission from engines as injection characteristics have great influences on the process of combustion. For example, increasing the fuel injection pressure can improve the fuel atomization and subsequently improve the combustion process, resulting in a higher brake thermal efficiency, producing less HC, CO, PM emissions, but more NOx emission. Pilot injection help in reducing combustion noise and NOx emissions and immediate post injection may help in soot oxidation and late post injection helps in regeneration of diesel particulate filter. This article aims at a comprehensive review of various fuel injection strategies viz varying injection pressure, injection rate shapes, injection timing and split/multiple injections for engine performance improvement and emissions control. Although every strategy has its own merits and demerits, they are explained in detail, in view of helping researchers to choose the better strategy or combination for their applications.

234 citations


Journal ArticleDOI
01 Jul 2013-Energy
TL;DR: In this article, the performance, emissions and combustion characteristics of biodiesel derived from non-edible Karanja oil in an unmodified diesel engine and to compare the results with baseline results of diesel fuel.

229 citations


Journal ArticleDOI
TL;DR: In this article, a solar-powered high temperature differential Stirling engine was considered for optimization using multiple criteria, including the output power and overall thermal efficiency, and the Pareto optimal frontier was obtained and a final optimal solution was also selected using various decision-making methods.

227 citations


Journal ArticleDOI
TL;DR: In this paper, the authors present a review of technologies suitable for utilisation of waste heat energy, with specific focus on low grade heat, including: (i) chemical heat pumps, such as adsorption and absorption cycles for cooling and heating; (ii) thermodynamic cycles such as the organic Rankine cycle (ORC), the supercritical Rankine Cycle (SRC), and the trilateral cycle (TLC), with further focus on expander and zeotropic mixtures, and (iii) thermal energy storage, including sensible and latent thermal energy storages and

224 citations


Journal ArticleDOI
Dongxiang Wang1, Xiang Ling1, Hao Peng1, Lin Liu1, LanLan Tao1 
01 Feb 2013-Energy
TL;DR: In this paper, the authors proposed a thermal efficiency model theoretically based on an ideal ORC to analyze the influence of working fluid properties on the thermal efficiency, the optimal operation condition and exergy destruction for various heat source temperatures were also evaluated utilizing pinch point analysis and ex-ergy analysis.

217 citations


Journal ArticleDOI
TL;DR: In this paper, the output power and engine thermal efficiency were optimized and total pressure losses were minimized using NSGA algorithm and finite speed thermodynamic analysis on Stirling cycle and Stirling engine.

Journal ArticleDOI
TL;DR: In this paper, the dimensionless thermo-economic objective function, thermal efficiency and dimensionless power output are optimized for a dish-Stirling system using finite time thermoeconomic analysis and NSGA-II algorithm.

Journal ArticleDOI
01 Sep 2013-Energy
TL;DR: In this article, the optimal design of MW-size organic Rankine cycles by employing the multi-objective optimization with the genetic algorithm as the optimizer is proposed, where three objective functions are considered: thermal efficiency, total volume of the system and net present value.

Journal ArticleDOI
TL;DR: In this paper, an experimental study was conducted on a Euro IV diesel engine to evaluate the performance, combustion and emission characteristics of pure biodiesel and its blend fuels, and the results showed that the use of biodiesel/blend fuels resulted in a higher brake specific fuel consumption, especially at low engine speed and partial load conditions.

Journal ArticleDOI
TL;DR: In this paper, a review of the technologies involved in CCHP systems based on biomass combustion is presented, and some guidelines are proposed to develop small-scale C-CHP plants in an energy efficient way.

Journal ArticleDOI
TL;DR: In this paper, a mathematical model based on the finite-time thermodynamics has been developed so that the output power and thermal efficiency and the rate of entropy generation of the solar Stirling system with finite rate of heat transfer, regenerative heat loss, conductive thermal bridging loss and finite regeneration process time are obtained.

Journal ArticleDOI
TL;DR: In this paper, a small-scale organic Rankine cycle (ORC) was used to harness the waste heat from an internal combustion engine, and the performance of a light-duty diesel engine with a dual-loop ORC was analyzed.

Journal ArticleDOI
TL;DR: In this article, the effect of ethanol and methanol fumigation on engine performance and emission of diesel engine has been critically analyzed, and it has been found that the application of alcohol fumigated technique leads to a significant reduction in the more environment concerning emissions of carbon dioxide (CO₂) up to 7.2%, oxides of nitrogen (NO x ) up to 20% and particulate matter (PM), up to 57%. However, increase in carbon monoxide (CO) and hydrocarbon (HC) emission have been found after use of alcohol
Abstract: Fossil fuels are the most imperative parameters to flourish the every sphere of modern civilization including industrial development, transportation, power generation and easing the accomplishment of works. The rapid increase in usage of fossil fuel has unavoidable deleterious effect on environment. The international consciousness for environment protection is growing and ever more strict emission legislations are being enacted. Simultaneously the storage of fossil fuel is depleting. Hence, the above situations promote the scientists to find alternative sustainable fuels along with their suitable using technique which will reduce the pollutant emission and will be applicable for gaining satisfactory engine performance. In these perspectives, alcohol fumigation is getting high demand as an effective measure to reduce pollutant emission from diesel engine vehicles. Alcohol fumigation is a dual fuel engine operation technique in which alcohol fuels are premixed with intake air. The aim of this paper is to identify the potential use of alcohols in fumigation mode on diesel engine. In this literature review, the effect of ethanol and methanol fumigation on engine performance and emission of diesel engine has been critically analyzed. A variety of fumigation ratios from 5% to 40% have been applied in different types of engines with various types of operational mode. It has been found that the application of alcohol fumigation technique leads to a significant reduction in the more environment concerning emissions of carbon dioxide (CO₂) up to 7.2%, oxides of nitrogen (NO x ) up to 20% and particulate matter (PM) up to 57%. However, increase in carbon monoxide (CO) and hydrocarbon (HC) emission have been found after use of alcohol fumigation. Alcohol fumigation also increases the BSFC due to having higher heat of vaporization. Brake thermal efficiency decreases at low engine load and increases at higher engine load.

Journal ArticleDOI
TL;DR: In this paper, the authors studied the thermodynamic aspects of PTES, including energy and power density, and the various sources of irreversibility and their impact on round-trip efficiency.

Journal ArticleDOI
TL;DR: In this article, performance, emission and combustion characteristics of Karanja oil blends (K10, K20, K50 and K100) with mineral diesel were investigated in unheated conditions in a direct injection compression ignition (DICI) engine at different engine loads and constant engine speed (1500 rpm) vis-a-vis baseline data from mineral diesel.

Journal ArticleDOI
TL;DR: In this paper, the effect of ethanol on combustion and emissions in premixed low temperature combustion (LTC) was investigated in a four cylinders heavy-duty diesel engine, where the biodiesel was used as an additive to prevent the stratification of ethanol and diesel blends.

Journal ArticleDOI
TL;DR: In this paper, the energy utilization efficiency of a gasoline engine and the recovery potential for waste heat energy, energy distribution, and exergy energy characteristics of a naturally aspirated gasoline engine have been studied by combining the methods of energy and ex-ergy analysis.

Journal ArticleDOI
01 Apr 2013-Fuel
TL;DR: In this paper, an experimental investigation has been carried out to evaluate the effect of using diethyl ether as additive to biodiesel on the combustion, performance and emission characteristics in an unmodified diesel engine at different loads and constant engine speed.

Journal ArticleDOI
01 Nov 2013-Energy
TL;DR: In this article, the authors proposed a cascade Rankine cycle, which recovers LNG (liquefied natural gas) cold energy for power generation, optimizes the cycle by investigating the effects of key parameters on its performance, and compares its thermal efficiency, exergy efficiency and economic evaluation to those of the conventional alternatives.

Journal ArticleDOI
TL;DR: In this article, a supercritical carbon dioxide based Brayton cycle for possible concentrated solar power applications is investigated and compared with trans-and sub-critical operations of the same fluid, and it is found that supercritical cycle is capable of producing power with a thermal efficiency of >30% even at a lower source temperature (820K) and accounting for foreseeable non-idealities albeit with a higher turbine inlet pressure (similar to 300 bar).
Abstract: Supercritical carbon dioxide based Brayton cycle for possible concentrated solar power applications is investigated and compared with trans- and sub-critical operations of the same fluid. Thermal efficiency, specific work output and magnitude of irreversibility generation are used as some of the performance indicators. While the thermal efficiency increases almost linearly with low side pressure in the sub- and trans-critical cycles, it attains a maximum in the supercritical regime at 85 bar after which there are diminishing returns on increasing the low side pressure. It is also found that supercritical cycle is capable of producing power with a thermal efficiency of >30% even at a lower source temperature (820K) and accounting for foreseeable non-idealities albeit with a higher turbine inlet pressure (similar to 300 bar) which is not matched by a conventional sub-critical cycle even with a high source temperature of 978K. The reasons for lower efficiency than in an ideal cycle are extracted from an irreversibility analysis of components, namely, compressor, regenerator, turbine and gas cooler. Low sensitivity to the source temperature and extremely small volumetric flow rates in the supercritical cycle could offset the drawback of high pressures through a compact system.


Journal ArticleDOI
TL;DR: In this article, the influence of device geometry on thermal stress, thermal efficiency and output power of a thermo-electric power generator is examined, and the finite element method is incorporated to predict temperature and stress fields in the thermo electric device.

Journal ArticleDOI
TL;DR: In this article, the authors measured the performance of different biodiesel fuel blends and found that B50 gives the highest peak pressure at 1750-rpm, while B10 gives the higher peak pressure in low speed at low speed, 1000-rpm.
Abstract: Jatropha-curcas as a non-edible methyl ester biodiesel fuel source is used to run single cylinder, variable compression ratio, and four-stroke diesel engine. Combustion characteristics as well as engine performance are measured for different biodiesel – diesel blends. It has been shown that B50 (50% of biodiesel in a mixture of biodiesel and diesel fuel) gives the highest peak pressure at 1750 rpm, while B10 gives the highest peak pressure at low speed, 1000 rpm. B50 shows upper brake torque, while B0 shows the highest volumetric efficiency. B50 shows also, the highest BSFC by about (12.5–25%) compared with diesel fuel. B10 gives the highest brake thermal efficiency. B50 to B30 show nearly the lowest CO concentration, besides CO concentration is the highest at both idle and high running speeds. Exhaust temperature and NO x are maximum for B50. Delay period is measured and correlated for different blends. Modified empirical formulae are obtained for each blend. The delay period is found to be decreased with the increase of cylinder pressure, temperature and equivalence ratio.

Journal ArticleDOI
01 Feb 2013-Fuel
TL;DR: In this paper, a novel emulsion fuel with nano-organic additives is introduced, which is transparent and light green with superior stability, and the performance and emissions of a diesel engine with common-rail fuel supply system are tested and compared with pure diesel.

Journal ArticleDOI
TL;DR: In this article, a thermoelectric cooling and heating system using photovoltaic/thermal (PV/T) dual function modules is proposed to improve the thermal efficiency of buildings.