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Observations of UV radiation (290–400 nm) at Yanting, China (31°16′ N, 105°27′ E and 420 m above sea level) from 2005 to 2012 were used for investigating UV variability and its relationship with global solar radiation in Southwest China. Daily UV/G ratios generally increased from 3.7% in January to 4.5% in July with annual mean value of 4.2%. Clearness index was used for characterizing sky conditions...
In this paper the impact of flat plate reflectors (bottom, top, left and right reflectors) made of Al, on total solar radiation on a solar collector during a day time over a whole year is analyzed. An analytical model for determining optimum tilt angles of a collector and reflectors for any point on the Earth is proposed. Variations of reflectors' optimal inclination angles with changes of the collector's...
This paper examines the role of state level institutional differences in attracting FDI (foreign direct investment) in wind energy in India. The role of institutional differences is measured by means of constructing a policy index using five key policies in wind energy: feed-in-tariff, open access transmission, third party sale, banking, and wheeling charges. Panel data techniques are then employed...
This paper assesses the natural gas supply security of 23 importing countries from divergent regions of the world for the period between 2001 and 2013. The indicators used for the study are the volume of imported natural gas, the number of natural gas suppliers, the level of dependency on one country, import dependency, the fragility of supplier countries, and the share of natural gas in primary energy...
The purpose of this work is to collect and interrelate the fundamental concepts about exergy transfer analysis and local exergy cost applied to the analysis of microwave heating systems. First, thermoeconomics and exergoeconomics are reviewed. Local exergy analysis is presented next, including local efficiency, and local cost associated. Emphasis is put on local cost that an electromagnetic field...
Over the past three years Italy has seen a rapid growth in the PV (photovoltaic) energy market, followed by an equally sudden decline when the government decided to reduce the incentives. This sharp change in the trend of the market calls into question the achievement of the so called Grid Parity and the possibility that the market is able to develop independently. The motivation of this paper is...
In this study, the life span of people living in seven regions of Turkey is estimated by applying the first and second laws of thermodynamics to the human body. The people living in different regions of Turkey have different food habits. The first and second laws of thermodynamics are used to calculate the entropy generation rate per unit mass of a human due to the food habits. The lifetime entropy...
The international regulations on fuel efficiency and NOx emissions of commercial ships motivate the investigation of new system layouts, which can comply with the regulations. In combustion engines, measures to reduce the fuel consumption often lead to increased NOx emissions and careful consideration of this trade-off mechanism is required in the design of marine propulsion systems. This study investigates...
The dynamic behavior of the PEM (proton exchange membrane) fuel cell stack has great effect on the safety and effective operation of its applications. In this paper, a self-designed bulb-array is used to simulate the various loading conditions and study the dynamic behavior of a 2 kW PEM fuel cell stack. An evaluation index, including oscillation rate, pressure variation and dynamic resistance factor,...
Dissection of the power output in a row of working turbines and the reliance on wind course in respect to the column heading is examined. The point is to portray the extent of the wake impacts and give a sign of the indication of wind bearing. The target is to delineate whether the uniting of wakes inside extensive wind homesteads can be depicted by basic direct models or whether the consideration...
A new, symmetrical, high rate, solid-state EDLC (electrical double layer capacitor) has been fabricated employing a plastic crystal SN (succinonitrile) based GPE (gel polymer electrolyte) and GNPs (graphene nano-platelets) as electrodes. The free-standing GPE film containing poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) exhibits the excellent suitability as electrolyte in EDLC due to...
Analysing different future trajectories of technological developments we assess the prospects for Nordic carbon-intensive industries to significantly reduce direct CO2 emissions in the period 2010–2050. This analysis covers petroleum refining, integrated iron and steel production, and cement manufacturing in the four largest Nordic countries of Denmark, Finland, Norway, and Sweden. Our results show...
A large number of indices claim to quantify the performance of a country in attaining the goal of energy security and energy sustainability. The paper compares three different indices, viz., ‘Energy Sustainability Index’, ‘International Index of Energy Security Risk’ and ‘Energy Architecture Performance Index’ along with their variants to examine if they provide consistent results for various countries...
Barley straw was successfully converted to bio-crude by hydrothermal liquefaction at temperature of 280–400 °C using an alkali catalyst (K2CO3) in our previous work, and the maximum bio-crude yield was obtained at 300 °C. This paper extends previous work on studying liquefaction behavior of barley straw without and with K2CO3 at 300 °C. The effect of alkali catalyst on product distribution was investigated,...
Load following is the potential for a power plant to adjust its power output as demand and price for electricity fluctuates throughout the day. In nuclear power plants, this is done by inserting control rods into the reactor pressure vessel. This operation is very inefficient as nuclear power generation is composed almost entirely of fixed and sunk costs; therefore, lowering the power output doesn't...
This article discusses the policy of opportunistic maintenance, considering more than one decision criterion by using a multi-attribute value function, for a study developed for a cogeneration system that uses sugarcane bagasse at a power plant in northeastern Brazil, where policy defines what maintenance tasks should be adopted. These policies include minimal repairs, opportunistic maintenance, and...
In this paper, an economic system optimization of an air-cooled organic Rankine cycle, powered by geothermal heat, is performed. The goal is to find the configuration of the ORC (organic Rankine cycle) which gives the highest possible net present value for the project. The cycle parameters, heat exchanger geometry and air-cooled condenser geometry are optimized together. The developed method is applied...
This paper presents energy and exergy assessments of a new integrated system with different psychrometric processes for HVAC&R applications. The mass, energy, entropy and exergy balance equations for all system components and processes are developed for analysis and performance assessment purposes. In addition, a novel integrated system with psychrometric processes is proposed and thermodynamically...
In the present study, the combustion and emission characteristics under various equivalence ratio up to stoichiometric condition were experimentally investigated in a CI (compression ignition) engine. In order to control the equivalence ratio, the O2 mole fraction of intake gas was reduced from 21 to 11.16 % by adding only N2 to intake gas while the injected fuel quantity was held constant. The test...
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