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As population grows considerably in the world, the correlation between intensity of population in urban areas and energy intensity becomes an important issue in energy field. This paper aims at examining the effects of urbanization on energy intensity for 10 Asian countries by employing annual data from 1990 to 2014. The Asian countries are Bangladesh, China, India, Indonesia, Malaysia, Nepal, Philippines,...
The Korean government has given efforts to reduce green-house gas emissions. In order to avoid the monolithic system that only focuses on reducing the emission without considering operational environments of firms, the government should encourage respective firms to improve their energy efficiency which wastes less energy but produces maximum economic revenue. This paper employed a DEA (Data Envelopment...
In the present investigation, electrochemically nitrided surface was developed on 316L stainless steel (SS) through potentiostatic method using an aqueous solution containing 0.1 M HNO3 and 0.5 M KNO3 at room temperature. The formation of nitrides was confirmed by X - ray photoelectron spectroscopy (XPS) and the formed nitrides existed in the form of mixed nitrides viz, CrN, Cr2N and nitrogen incorporated...
Following new and innovative concepts of energy recovery which use micro-hydro impulse turbines in drinking water systems, more sophisticated turbine designs become essential to improve energy recovery efficiency. In the case of implementing a hydraulic impulse turbine with tailwater depression in such systems, one major challenge to optimising overall efficiency is the reduction of the turbine's...
Direct ethanol fuel cells (DEFCs) are promising substitute power sources for compact and mobile applications. Passive feed systems are especially desirable because they are less expensive, more compact and simpler than the active systems. Aiming for the introduction of passive DEFCs in the market, this work describes a steady-state and one-dimensional model considering the electrochemical reactions...
An experimental evaluation of HFO-1336mzz-Z as a low global warming potential working fluid for ORC systems in micro-scale low temperature applications has been conducted. The energy performance in a fully monitored ORC module has been analyzed varying the heat source temperatures between 140 °C and 160 °C and heat sink temperatures between 25 °C and 40 °C. The ORC module uses a regenerative configuration...
Task/ambient air conditioning (TAC) system is reported to be an energy efficient technology with available methods to control thermal comfortable level for sleeping environments. Better performance in energy saving for TAC systems in sleeping environment has been demonstrated in previous studies. However, it should be noticed that the building envelope thermal load affects the indoor thermal environment...
This paper highlights the use of metaheuristic approaches to perform the energy management of a hybrid Fuel Cell/Ultra-Capacitor Electric Vehicle considering hydrogen consumption, Fuel Cell durability and computational time as key performance criteria. The considered architecture is an integrated rule-based metaheuristic approach that combines the simplicity and the effectiveness of rule based and...
Direct steam generation in parabolic-trough solar collector requires reliable and efficient two-phase flow modelling tools. One-dimensional models based on 6 equations are a suitable approach. The present article aims to show that RELAP5 is able to simulate a single-loop system including transients caused by sudden events like solar collector defocusing or fast changes in direct solar irradiance....
The VIV (Vortex Induced Vibration) energy harvesting of two bluff bodies in tandem arrangement is investigated using two-dimensional numerical simulations in the spacing range of 2–50 diameters. Five groups of bluff bodies with different cross sections (Triangular prism, Square prism, Pentagon prism, Circular cylinder and Cir-Tria prism) are analyzed. To satisfy the needs of practical application,...
A numerical model of a thermoelectric generator (TEG) is developed using the finite element method, and the convective heat-transfer coefficient and back pressure are calculated. The effect of the back pressure on the engine power loss is analyzed at different rotating speeds using GT-POWER simulation software. The optimal thermoelectric performance is analyzed considering the maximum net power output...
Performance of transcritical CO2 Rankine cycles with and without reheat process is investigated thermo-economically in low-grade waste heat recovery applications. Two reheating scenarios are proposed to evaluate the effect of bounded and unbounded reheats on the cycle. In the first method, the constant available heat flow is distributed between the evaporator and the reheater via an optimized ratio,...
Nanofluid application as the working fluid is proposed as a way for improving the solar system performance. In this study, a dish concentrator with a cylindrical cavity receiver was numerically modeled. Four different nanofluids including Al2O3/thermal oil, Cu/thermal oil, SiO2/thermal oil, and TiO2/thermal oil, were investigated as the working fluid of the solar system. The effects of the nanoparticles...
The aim of this study is to establish an energy use efficiency and GHG emissions (EUE-GHG) model to promote ecological agriculture, not only examining these indicators on crop production in Anhui Province from 1990 to 2014, but also comparing them among 16 provincial cities in 2014. The results reveal that energy use efficiency decreased significantly from 3.75 to 1.87 during 1990–2005, and then increased...
The demand for more efficient energy utilization is leading to the need for efficient thermal energy storage (TES) systems. High temperature, low thermal conductivity concrete has been widely used in solid TES modules. The thermal conduction in concrete is improved by adding a fixed amount of high thermal conductivity materials into the original material with the characteristic time for thermal storage...
The development of the new economic normal is influencing the total economy, the industrial structure and the layout in China to a great extent. The pillar industry faces a transformation from factor-driven to innovation-driven. The traditional electricity demand prediction model is no longer applicable due to these new factors. Thus, this paper makes a quantitative analysis of the new influencing...
Organic Rankine Cycle (ORC) is regarded as a very suitable method to recover the waste heat of internal combustion engines. Engines often operate under variable working conditions, so ORC systems are also under unstable state which means it is important to research the dynamic response. There are many kinds of working fluids and various dynamic response characters are reflected owing to their different...
This manuscript analyzes the influencing factors of energy consumption growth in Guangdong Province using the logarithmic mean Divisia index I (LMDI) decomposition method developed based on the physical processes of energy utilization from the primary energy supply to end-use sectors. By introducing the input-output method for mapping the energy allocation diagrams of Guangdong Province, we derive...
A chemical kinetic mechanism of n-butanol/iso-octane blends (Model BI) was established on the basis of a n-butanol reaction submechanism and part of a high-temperature oxidation mechanism of iso-octane. Model BI was validated against laminar flame speeds, ignition delay times and JSR data, and proved to be applicable and reliable. It also found that the laminar flame speed of blends increased linearly...
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