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Showing papers on "Thermal efficiency published in 2005"


Journal ArticleDOI
TL;DR: In this article, the effects of different ethanol-diesel blended fuels on the performance and emissions of diesel engines have been evaluated experimentally and compared in a water-cooled single-cylinder Direct Injection (DI) diesel engine.

401 citations


Journal Article
TL;DR: In this article, the influence of cetane number improver on heat release rate and emissions of a high-speed diesel engine fueled with ethanol-diesel blend fuel was investigated.
Abstract: The influence of cetane number improver on heat release rate and emissions of a high-speed diesel engine fueled with ethanol-diesel blend fuel was investigated.Different percentages of cetane number enhancer(0~0_0,0.2~0_0,0.4~0_0) were added to blends,and the engine tests were performed on a high speed diesel engine.The results show that the engine power decreases slightly; the thermal efficiency improves remarkably,and the NO_x and smoke emissions decrease simultaneously when diesel engine is fueled with blends.Besides, the engine power can be recovered,NO_x and smoke emissions are further reduced when cetane number improver is added to blends.By the combustion analysis,it can be found that the ignition delay prolongs;the total combustion duration shortens,and the maximum heat release rate increases for ethanol-diesel blend fuel when compared to diesel fuel; in addition,the combustion characteristics of ethanol-diesel blend fuel at large load may be recovered to diesel fuel by cetane number improver. However a large difference still exists at lower load.

327 citations


Journal ArticleDOI
TL;DR: In this article, the performance of single and double slope multi-wick solar distillation systems in quasi-steady state conditions has been analyzed based on the basic energy balance for both the systems.

171 citations


Reference BookDOI
23 Aug 2005
TL;DR: In this article, the authors present a classification of thermal processes based on temperature, velocity, and humidity properties of the air, as well as their relationship with heat and mass transfer.
Abstract: INTRODUCTION BACKGROUND BASICS Units, Dimensions, Conversions, Common Terms, Definitions Mass Balance Energy Balance Heat Transfer Fundamentals Fluid Flow Rheological Properties Thermophysical Properties THERMAL PROCESSING Introduction Historical Perspectives Classification of Thermal Processes Principles of Thermal Processing Thermal Resistance of Microorganisms Lethality Concept Characterization of Heat Penetration Data Thermal Process Calculations Thermal Process Calculations for Pasteurization Commercial Canning Operations Thermal Process Equipment Commercial Retorts Quality Improvement in Thermally Processed Foods Novel Thermal Processing Techniques LOW TEMPERATURE PRESERVATION Introduction Refrigerated Storage Food Freezing FOOD DEHYDRATION Introduction Dehydration Fundamentals Drying Curve Mass and Energy Balance in Air Drying Air-Moisture Relationships Effect of Air Temperature, Velocity, and Humidity on Drying Effect of Product Characteristics on Drying Dryer Selection Common Drying Systems Novel Drying Techniques Energy Aspects and Thermal Efficiency Quality and Storage Stability of Dehydrated Foods Trends SEPARATION AND CONCENTRATION Introduction Evaporation Membrane Processing Freeze Concentration Extraction Supercritical Fluid Extraction Osmotic Dehydration (OD) Future Trends APPENDIX A: Conversion Factors APPENDIX B: Thermophysical Properties APPENDIX C: Heat and Mass Transfer Charts REFERENCES CITED ADDITIONAL READING MATERIAL INDEX

168 citations


Journal ArticleDOI
TL;DR: In this paper, the authors modeled the air gap membrane distillation process as a two-dimensional conjugate problem in which a simultaneous numerical solution of the momentum, energy and diffusion equations of the feed and cold solutions have been carried out.

153 citations


Journal ArticleDOI
TL;DR: In this paper, a fuel processor, which incorporates a catalytic autothermal reformer (ATR), a sulfur trap, and a water-gas-shift (WGS) bed engineered to thermally integrate the ATR and WGS processes for improved thermal efficiency, was developed and tested with natural gas as a hydrogen generator for fuel cell applications.

147 citations


Journal ArticleDOI
TL;DR: In this article, a model of a two-stage semiconductor thermoelectric-generator with external heat-transfer is built, and performance of the generator, assuming Newton's heat transfer law applies, is analyzed using a combination of finite-time thermodynamics and non-equilibrium thermodynamics.

143 citations


Patent
27 Jul 2005
TL;DR: In this article, a heat absorbing radiator and a gas turbine engine or a reciprocating piston engine are used to recapture and reconvert wasted heat energies into electric power and finally into hydrogen-deuterium fuel by having the engine's tailpipes submerged in cold compressed air inside the heat absorbing radiators.
Abstract: A heat absorbing radiator and a gas turbine engine or a reciprocating piston engine are used to recapture and reconvert wasted heat energies into electric power and finally into hydrogen-deuterium fuel by having the engine's tailpipes submerged in cold compressed air inside the heat absorbing radiator pipes in reverse air flow to further drive the same engine. In order to capture fusion heat energy a hydrogen bomb is detonated in deep ocean to catch flames by water and the hot water energizes compressed air inside heat absorbing radiator pipes. In order to produce fusion energy an electric arc is passed across liquid or gaseous deuterium by an electro-plasma torch and a sparkplug in an internal combustion engine, or by detonating dynamite inside liquid deuterium. Diamond is produced by placing carbon inside a hydrogen bomb. Deuterium fusion flame is used first in smelting glass to large sizes before running an engine.

134 citations


Journal ArticleDOI
TL;DR: In this article, a 10 to 20MWth Synthetic Natural Gas (SNG) production process from wood has been performed, which combines process modeling and process integration techniques to achieve a thermal efficiency of 57.9% based on the Lower Heating Value (LHV).

127 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of insulated combustion chamber surfaces on the turbocharged, direct injection Diesel engine performance was experimentally investigated, and it was concluded that the exhaust gas process was the most important source of available energy, which must be recovered via secondary heat recovery devices.

122 citations


Journal ArticleDOI
TL;DR: In this paper, the authors studied the influence of ambient temperature on the performance of a thermal-power plant with a multiple-shaft configuration, and the most relevant results obtained from a thermodynamic simulation, in which the Gate Cycle Software version 5.51.0.r was used, are the curves of generated power, as well as the heat rate and thermal efficiency as functions of ambient temperatures and the supplementary firing.

Journal ArticleDOI
TL;DR: In this paper, the performance of an air-standard Otto cycle with heat transfer loss and variable specific heat of working fluid is analyzed by using finite-time thermodynamics, and the relationship between the power output and the compression ratio is derived by detailed numerical examples.

Journal ArticleDOI
TL;DR: In this article, an exergy loss based economic analysis of biomass utilization is proposed, which shows the opportunity of using biomass in plants with a thermodynamic efficiency higher than a minimum value.

Journal ArticleDOI
TL;DR: In this paper, the authors evaluate the use of a genetic algorithm optimization scheme to control a commercially available thermal reservoir simulator in order to optimize the steam injection strategy to reduce the cumulative oil to steam ratio (cSOR).
Abstract: Many field tests of the steam assisted gravity drainage (SAGD) process have been conducted and have shown that the process is a technically effective one at extracting oil from heavy oil and bitumen reservoirs. However, it has not been firmly established whether the technology is operated at optimized conditions to yield maximum economic returns. This is especially important because typically SAGD depends on the combustion of natural gas to generate steam and this is the dominant cost. The cost of natural gas can be significant when natural gas prices are high. This research evaluates the use of a genetic algorithm optimization scheme to control a commercially available thermal reservoir simulator in order to optimize the steam injection strategy to reduce the cumulative oil to steam ratio (cSOR). The reservoir description is typical of that from a low to medium quality Athabasca reservoir. The results show that the injection strategy can be altered to reduce the cSOR up to 50% from a uniform injection pressure strategy to 1 after the steam injection strategy has been optimized. The optimized profile has high steam injection pressure at the beginning of the process before the steam chamber reaches the top of the oil-rich zone. Before the chamber reaches the oil pay, with high injection pressure, the saturation temperature is high and there are no thermal losses to the overburden. After the chamber reaches the top of the formation, the injection pressure is lowered throughout the remainder of the process. This reduction of injection pressure implies that the saturation temperature falls and consequently the losses to the overburden are lowered. Thus the overall thermal efficiency of the process is enhanced. The optimized strategy is compared to processes operating at 1,000 and 2,000 kPa constant injection pressure.

Journal ArticleDOI
TL;DR: In this paper, the authors have shown that the Integrated Solar Combined Cycle System with 67MW e solar field (ISCCS-67) is the most suitable plan for the first solar power plant in Iran.

Journal ArticleDOI
TL;DR: In this paper, an alternative method of heat extraction from salinity-gradient solar ponds is investigated with the aim of increasing the overall energy efficiency of collecting solar radiation, storing heat and delivering this heat to an application.

Journal ArticleDOI
TL;DR: In this article, an approach to predict ash deposits in coal-fired boilers by means of artificial neural networks is described. But the approach is of a grey box nature, decomposing the problem into logical parts, and avoiding the use of sophisticated data.

Journal ArticleDOI
TL;DR: In this article, the thermal stability and mechanical properties of these parts have been studied, and the high-temperature strength and thermal stability of components were also no changes after heat treatment for 500h at 1700°C in an air atmosphere.
Abstract: Melt growth composites (MGCs) have a microstructure, in which continuous networks of single-crystal Al 2 O 3 phases and single-crystal oxide compounds (YAG (Y 3 Al 5 O 12 ), GAP (GdAlO 3 )) interpenetrate without grain boundaries. Therefore, the MGCs have excellent high-temperature strength characteristics, creep resistance, superior oxidation resistance and thermal stability in the air atmosphere at very high temperature. To achieve ultra-high thermal efficiency and low NO x emission for gas turbine systems, we produced turbine nozzle vanes that does not require cooling and heat shield panels for combustor liners. The thermal stability and mechanical properties of these parts have been studied. The high-temperature strength characteristics and the thermal stability of components were also no changes after heat treatment for 500 h at 1700 °C in an air atmosphere. The favorable properties of melt growth composite have been discussed for possible application in gas turbine system.

Patent
14 Jun 2005
TL;DR: In this paper, an absorption refrigeration system is used to pre-cool an air-gas mixture before it enters the high-pressure compressor, thereby increasing the thermal efficiency of the turbine engine.
Abstract: A turbine engine system and a method for using the turbine engine system that includes at least one low-pressure compressor, at least one high-pressure compressor, at least one low-pressure turbine, and at least one high-pressure turbine. In addition, the turbine engine system includes an absorption refrigeration system that is used to pre-cool an air-gas mixture before it enters the high-pressure compressor. As such, the pre-cooled mixture is easier to compress, thereby increasing the thermal efficiency of the turbine engine. Additionally, the exhaust heat from the air-gas mixture that is pre-cooled may be used to drive the absorption refrigeration system. Lastly, water, may be extracted from the evaporator of the absorption refrigeration cycle.

Journal ArticleDOI
Seref Soylu1
TL;DR: In this article, a zero-dimensional thermodynamic model that contains a simple heat release sub-model and an autoignition model was used in a predictive fashion to better understand the in-cylinder processes and the efficiency potential of a natural gas engine in the HCCI mode.

Journal ArticleDOI
TL;DR: In this article, the performance of a generalized irreversible reciprocating heat engine cycle model consisting of two heating branches, two cooling branches and two adiabatic branches with heat-transfer loss and friction-like term loss was analyzed using finite-time thermodynamics.

Journal ArticleDOI
TL;DR: In this article, an experiment study was carried out in order to investigate feasibility of CO 2 -based Rankine cycle powered by solar energy, which achieved a cogeneration of heat and power, consisting of evacuated solar tube collectors, power generating turbine, heat recovery system, and feed pump.
Abstract: An experiment study was carried out in order to investigate feasibility of CO 2 -based Rankine cycle powered by solar energy. The proposed cycle is to achieve a cogeneration of heat and power, which consists of evacuated solar tube collectors, power generating turbine, heat recovery system, and feed pump. The Rankine cycle of the system utilizes solar collectors to convert CO 2 into high-temperature supercritical state, used to drive a turbine and produce electrical power. The cycle also recovers thermal energy, which can be used for absorption refrigerator, air conditioning, hot water supply so on for a building. A set of experimental set-up was constructed to investigate the performance of the CO 2 -based Rankine cycle. The results show the cycle can achieve production of heat and power with reasonable thermodynamics efficiency and has a great potential of the application of the CO 2 -based Rankine cycle powered by solar energy. In addition, some research interests related to the present study will also be discussed in this paper.

Journal ArticleDOI
Rongrong Zhang1, Xuesheng Lu1, S. Li1, Wensheng Lin1, Aiqin Gu1 
TL;DR: In this article, the authors analyzed the heating performance of a gas engine driven air to water heat pump using a steady state model and showed that engine waste heat can provide about 1/3 of the total heating capacity in this gas engine-driven air-to-water heat pump.

Journal ArticleDOI
TL;DR: The design, fabrication, and testing of a novel system for thermal management for electric/hybrid vehicles based on Peltier-effect heat pumps are described, which shows the applicability of this type of technology for the thermal management of these type of vehicles.
Abstract: Assuring the right temperature in battery compartments of an electric or hybrid vehicle is crucial for the safe operation and the achievement of optimal performance of the batteries. This paper is about the design, fabrication, and testing of a novel system for thermal management for electric/hybrid vehicles. This system is based on Peltier-effect heat pumps. The experiment results show the applicability of this type of technology for the thermal management for this type of vehicles.

Journal ArticleDOI
TL;DR: In this article, the effects of hydrogen enriched LPG fueled engine on exhaust emission, thermal efficiency and performance were investigated, and the test engine was run at 1400rpm with a compression ratio of 8.8.

Journal ArticleDOI
TL;DR: In this article, an extended chemical looping combustion integrated in a steam-injected gas turbine cycle has been studied, which can achieve a thermal efficiency of 54% while 96% of the CO2 is captured and compressed to 110 bar.
Abstract: SUMMARY In this article, a novel cycle configuration has been studied, termed the extended chemical looping combustion integrated in a steam-injected gas turbine cycle. The products of this system are hydrogen, heat, and electrical power. Furthermore, the system inherently separates the CO2 and hydrogen that is produced during the combustion. The core process is an extended chemical looping combustion (exCLC) process which is based on classical chemical looping combustion (CLC). In classical CLC, a solid oxygen carrier circulates between two fluidized bed reactors and transports oxygen from the combustion air to the fuel; thus, the fuel is not mixed with air and an inherent CO2 separation occurs. In exCLC the oxygen carrier circulates along with a carbon carrier between three fluidized bed reactors, one to oxidize the oxygen carrier, one to produces and separate the hydrogen, and one to regenerate the carbon carrier. The impacts of process parameters, such as flowrates and temperatures have been studied on the efficiencies of producing electrical power, hydrogen, and district heating and on the degree of capturing CO2. The result shows that this process has the potential to achieve a thermal efficiency of 54% while 96% of the CO2 is captured and compressed to 110 bar. Copyright # 2004 John Wiley & Sons, Ltd.

Journal ArticleDOI
TL;DR: In this article, the performance characteristics of two types of regenerative steam-injection gas-turbine (RSTIG) systems are analyzed and they are compared with the performances of the simple, regenerative, water injection and steam injected gas-to-power cycles.

Journal ArticleDOI
Adnan Parlak1
TL;DR: In this paper, a Diesel cycle analysis taking combustion and heat transfer into account on performance has been performed, where the effect of heat transfer from the cylinder on exhaust temperature was also investigated for different heat transfer and combustion modes.

Journal ArticleDOI
TL;DR: In this article, a hybrid pneumatic power system (HPPS) was proposed to improve the energy efficiency and exhaust emission of an internal-combustion engine under different driving conditions.

Journal ArticleDOI
TL;DR: In this paper, the performance of an air standard Miller cycle with heat transfer loss and friction-like term loss was analyzed by using finite-time thermodynamics, and the relation between the power output and the compression ratio, between the thermal efficiency and compression ratio was derived.