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This work compares the performance and emissions of two dual-mode combustion concepts over different driving cycles by means of vehicle systems simulations. The dual-mode concept relies on switching between the dual-fuel concept known as reactivity controlled compression ignition (RCCI) and conventional diesel combustion (CDC) to cover the whole engine map. The experimental RCCI maps obtained with...
The concept of urban CO2 networks has been developed to deploy heat pump based district heating and cooling systems in dense urban areas. The use of the CO2 phase change reduces the cost of the heat distribution while allowing to recover waste heat that is typically rejected to the environment. The use of heat pumps to harvest heat from the environment and to supply heat to buildings allows one to...
The energy management of buildings currently offers a powerful opportunity to enhance energy efficiency and reduce the mismatch between the actual and expected energy demand, which is often due to an anomalous operation of the equipment and control systems. In this context, the characterisation of energy consumption patterns over time is of fundamental importance. This paper proposes a novel methodology...
With the integration of intermittent resources, more reserves are required for uncertainties. Traditionally, reactive power optimization in transmission network focuses on loss minimization problems, regarding loads as voltage-independent injections. In fact, the bus voltage magnitude affects the load active/reactive injection, providing a possibility for system operators to regulate the power of...
The impact of exhaust gas recirculation (EGR) on combustion and emissions in direct injection (DI) diesel engine is examined in a predominately computational study, where the influence of EGR rate and temperature at various injection timings and loads is addressed using an in-house, comprehensive, two-zone model of diesel combustion, which divides the cylinder contents into a non-burning zone (air)...
A new design named as integrated azimuth tracking solar tower is presented in which all of the heliostats and receiver are installed on an azimuth tracking device, multi heliostats are fixed to one horizontal shaft which rotate to track the solar elevation variance to reduce the number of tracking device. An optical and thermal performance model is developed and validated for it. Its annual performance...
Power transmission expansion planning (TEP) is a process affected by uncertainty that requires a long-term vision to anticipate requirements of interconnections among generators and load centers. Flexibility is an alternative to cope with uncertainty that increases social welfare. This article seeks for estimating the value of this flexibility and interpreting its meaning in the Colombian power system...
In this study, the influence of turbulence intensity on flame local structural and local propagation characteristics was studied. In order to achieve this, 50% H2/50% CO with equivalence ratio of 0.8 were conducted under different turbulence intensities ranging from 0 to 1.31 m/s at atmospheric pressure and temperature. The distribution of the flame local radius and flame local propagation speed and...
Coal-to-olefin (CTO) projects, an energy strategy, are increasing in number in China but suffer from high consumption and pollution. In this study, a life cycle assessment is studied to determine whether oil field gas-assisted CTO systems have the potential to solve these problems. Oil-to-olefin is presented for comparison. Results showed that the current CTO scenario generally exerts a higher environmental...
When supercritical carbon dioxide (SCO2) Brayton cycle is used for coal fired power plant, the significantly increased flow rate causes extremely large boiler pressure drops, and residual flue gas energy extraction becomes difficult. This paper contains two consecutive parts to resolve these issues. The first part deals with general analysis. Results show that, introducing intercooling and/or reheating...
A theoretical and experimental study was carried out on performance of a Tubular Solar Still (TSS) under vacuum operation condition, based on which a modified model was proposed. Theoretical analysis shows that a vacuum operation pressure augments the concentration differential of humid vapour around the trough and that around the condensation surface, intensifying the diffusion and natural convection...
Biogas, which primarily consists of methane (CH4) and carbon dioxide (CO2), is a renewable energy carrier, and can be upgraded to a natural gas substitute after removing trace impurities and CO2. Among the various CO2 separation technologies, amine absorption is generally considered to be energy intensive as regenerating the rich solution need additional heat to strip CO2. However, it could hardly...
The flame is very hard to keep steadily symmetrical for a wide flammability limit under some extreme combustion conditions (such as large heat loss and fuel of low caloric value). Recently, we manufacture a mesoscale combustor with a plate flame holder and preheating channels, which could take the advantage of the flow recirculation and heat recirculation effects. The experimental results show that...
The production of carbon-neutral, renewable, and environment-friendly biofuels is currently being implemented worldwide to mitigate the excessive use of petroleum-based fuels. Fast-growing lipid-producing microalgae, such as Scenedesmus obliquus, are considered ideal feedstocks for biofuel production. In this study, the separation of lipids from Scenedesmus obliquus microalgae was done through ultrasound-assisted...
Activated aluminum composites Al-X(X = Sn, Bi, Bi-Sn) were prepared by high-energy milling, and characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Their hydrogen generation was systematically investigated in tap water. The experimental results suggest that the ternary Al-Bi-Sn composites show the better hydrolysis properties than...
Dynamic economic dispatch (DED), mathematically, is a typical highly complex nonlinear multivariable strongly coupled optimization problem with equality and inequality constraints, especially considering valve-point effects. In this paper, a hybrid method named BBOSB by combining biogeography-based optimization (BBO) with brain storm optimization (BSO) is proposed. BBO has good local exploitation...
The influences of VVT on engine power performance were well summarized in previous studies from various aspects. However, most of the previous investigations were qualitative analysis and focused on the total effects of VVT without decoupling the influence factors. The primary cause is due to lack of an effective mathematic model to predict the IMEP of VVT engine. In this study, an approach to detect...
In this study, biodiesel production from castor oil has been investigated. Five independent variables including; methanol to oil (M:O) molar ratio, catalyst concentration, reaction temperature, time and stirring rate have been chosen to investigate their effect on biodiesel yield. Response Surface Methodology (RSM) via Rotatable Central Composite Design (RCCD) has been used to evaluate the influence...
Different configurations of a 100% renewable electricity system are possible, but not all are equally desirable in terms of the scale of material resources required to sustain them. This study compares different approaches for developing a 100% renewable electricity system on the basis of the material mass investment required to sustain their physical components. Electric grid modeling accounting...
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