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Total Energy Consumption (total + energy_consumption)
Selected AbstractsHydrogen for the Mobility of the Future Results of GM/Opel's Well-to-Wheel Studies in North America and EuropeFUEL CELLS, Issue 3 2003U. Winter Abstract General Motors conducted two well-to-wheel studies for fundamental clarification on the question of which is the cleanest and most environmentally sustainable source of energy for the mobility of the future. In both studies the complete energy chains were analyzed from fuel production using primary energy to the actual consumption of the fuel in the car, i.e. from the well up to the wheels of the vehicle (well to wheel). The aim of the studies was to evaluate total energy consumption on the one hand and, on the other, the total greenhouse gas emissions arising between the production of a fuel and its final use to power an automobile. The results of the studies clearly show that fuel cell vehicles can greatly reduce greenhouse gas emissions from passenger cars or, if they run on hydrogen from renewable energy sources, they can eliminate them entirely. Regenerative fuels, however, will be more expensive than current products. With the fuel cell, because of its superior efficiency (35 , 45% less energy consumption well to wheel), it will be possible to keep individual mobility affordable in the future. [source] Optimization of Train Speed Profile for Minimum Energy ConsumptionIEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 3 2010Masafumi Miyatake Member Abstract The optimal operation of railway systems minimizing total energy consumption is discussed in this paper. Firstly, some measures of finding energy-saving train speed profiles are outlined. After the characteristics that should be considered in optimizing train operation are clarified, complete optimization based on optimal control theory is reviewed. Their basic formulations are summarized taking into account most of the difficult characteristics peculiar to railway systems. Three methods of solving the formulation, dynamic programming (DP), gradient method, and sequential quadratic programming (SQP), are introduced. The last two methods can also control the state of charge (SOC) of the energy storage devices. By showing some numerical results of simulations, the significance of solving not only optimal speed profiles but also optimal SOC profiles of energy storage are emphasized, because the numerical results are beyond the conventional qualitative studies. Future scope for applying the methods to real-time optimal control is also mentioned. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source] Energy Saving Speed and Charge/Discharge Control of a Railway Vehicle with On-board Energy Storage by Means of an Optimization ModelIEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 6 2009Masafumi Miyatake Member Abstract The optimal operation of rail vehicle minimizing total energy consumption is discussed in this paper. In recent years, the energy storage devices have enough energy and power density to use in trains as on-board energy storage. The on-board storage can assist the acceleration/deceleration of the train and may decrease energy consumption. Many works on the application of the energy storage devices to trains were reported, however, they did not deal enough with the optimality of the control of the devices. The authors pointed out that the charging/discharging command and vehicle speed profile should be optimized together based on the optimality analysis. The authors have developed the mathematical model based on a general optimization technique, sequential quadratic programming. The proposed method can determine the optimal acceleration/deceleration and current commands at every sampling point under fixed conditions of transfer time and distance. Using the proposed method, simulations were implemented in some cases. The electric double layer capacitor (EDLC) is assumed as an energy storage device in our study, because of its high power density etc. The trend of optimal solutions such as values of control inputs and energy consumption is finally discussed. Copyright © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source] Risk factors for prostate cancer incidence and progression in the health professionals follow-up studyINTERNATIONAL JOURNAL OF CANCER, Issue 7 2007Edward Giovannucci Abstract Risk factors for prostate cancer could differ for various sub-groups, such as for "aggressive" and "non-aggressive" cancers or by grade or stage. Determinants of mortality could differ from those for incidence. Using data from the Health Professionals Follow-Up Study, we re-examined 10 factors (cigarette smoking history, physical activity, BMI, family history of prostate cancer, race, height, total energy consumption, and intakes of calcium, tomato sauce and ,-linolenic acid) using multivariable Cox regression in relation to multiple subcategories for prostate cancer risk. These were factors that we previously found to be predictors of prostate cancer incidence or advanced prostate cancer in this cohort, and that have some support in the literature. In this analysis, only 4 factors had a clear statistically significant association with overall incident prostate cancer: African,American race, positive family history, higher tomato sauce intake (inversely) and ,-linolenic acid intake. In contrast, for fatal prostate cancer, recent smoking history, taller height, higher BMI, family history, and high intakes of total energy, calcium and ,-linolenic acid were associated with a statistically significant increased risk. Higher vigorous physical activity level was associated with lower risk. In relation to these risk factors, advanced stage at diagnosis was a good surrogate for fatal prostate cancer, but high-grade (Gleason , 7 or Gleason , 8) was not. Only for high calcium intake was there a close correspondence for associations among high-grade cancer, advanced and fatal prostate cancer. Tomato sauce (inversely) and ,-linolenic acid (positively) intakes were strong predictors of advanced cancer among those with low-grade cancers at diagnosis. Although the proportion of advanced stage cancers was much lower after PSA screening began, risk factors for advanced stage prostate cancers were similar in the pre-PSA and PSA era. The complexity of the clinical and pathologic manifestations of prostate cancer must be considered in the design and interpretation of studies. © 2007 Wiley-Liss, Inc. [source] Error-aware and energy-efficient routing approach in MANETsINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 1 2009Liansheng Tan Abstract The lifetime of a network is the key design factor of mobile ad hoc networks (MANETs). To prolong the lifetime of MANETs, one is forced to attain a tradeoff of minimizing the energy consumption and load balancing. In MANETs, energy waste resulting from retransmission due to high bit error rate (BER) and high frame error rate (FER) of wireless channel is significant. In this paper, we propose two novel protocols termed multi-threshold routing protocol (MTRP) and enhanced multi-threshold routing protocol (EMTRP). MTRP divides the total energy of a wireless node into multiple ranges. The lower bound of each range corresponds to a threshold. The protocol iterates from the highest threshold to the lowest one and chooses those routes with bottleneck energy being larger than the current threshold during each iteration. This approach thus avoids overusing certain routes and achieves load balancing. If multiple routes satisfy the threshold constraint, MTRP selects a route with the smallest hop count to further attain energy efficiency. Based on MTRP, EMTRP further takes channel condition into consideration and selects routes with better channel condition and consequently reduces the number of retransmissions and saves energy. We analyze the average loss probability (ALP) of the uniform error model and Gilbert error model and give a distributed algorithm to obtain the maximal ALP along a route. Descriptions of MTRP and EMTRP are given in pseudocode form. Simulation results demonstrate that our proposed EMTRP outperforms the representative protocol CMMBCR in terms of total energy consumption and load balancing. Copyright © 2008 John Wiley & Sons, Ltd. [source] Computational energy analysis of an innovative isothermal chamber for testing of the special equipment used in the transport of perishable productsINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 10 2004S. K. Chatzidakis Abstract This paper describes an improved numerical simulation study of an isothermal chamber recently constructed at Zografou Campus of the National Technical University of Athens (NTUA) for the testing of special equipment used for transporting perishable foodstuffs in accordance with the United Nations ATP agreement. Using a transient finite difference model, a simulation is developed for a modern ATP test chamber and a typical specimen refrigerated vehicle to be tested. The simulation results are compared to experimental measurements taken under real conditions by a data acquisition system and a refrigerated semi-trailer as specimen. Proportional,integral control is employed for the regulation of the cooling and heating system. The impact of various parameters on the time required to reach the set-point temperature (tset) is investigated and the energy consumption is simulated for a period of 22 h. In particular, the impact of specimen insulation thickness and the thickness of the chamber insulation floor are considered in detail. The total energy consumption increases by approximately 16% when the concrete floor layer thickness is increased from 8 to 16 cm for typical initial conditions and desired chamber and specimen temperatures of 32.5 and 7.5°C, respectively. Using a floor insulation of 6 cm extruded heavy strain-resistant polystyrene reduces the energy consumption by at least 13%. Specimen insulation thickness increase from U -value of 0.35 W m,2 K to 0.75 W m,2 K result to an increase in energy consumption by a percentage of 28%. Thermal capacity, temperature of car body and specimen dimensions are also treated as variables that affect the total duration of an ATP test and its total energy consumption. Copyright © 2004 John Wiley & Sons, Ltd. [source] Impact of energy efficiency upgrade retrofits on the residential energy consumption in CanadaINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 9 2001Burak Guler Abstract The impact of various energy efficiency upgrade scenarios on the annual energy consumption of the Canadian housing stock is assessed using the Canadian Residential Energy End-use Model (CREEM). The energy efficiency upgrade scenarios that are considered include major retrofits, such as the improvement of the house envelope by adding insulation, and the replacement of the existing heating system and appliances by higher efficiency units, as well as minor retrofits, such as lighting fixture, thermostat, showerhead and aerator upgrades that reduce energy consumption. The economic feasibility of each upgrade was assessed using the indicator ,energy savings per dollar investment'. The results indicate that the energy savings potential of the retrofits is rather small, resulting in savings of 0,8 per cent of the total energy consumption of the Canadian housing stock. Copyright © 2001 John Wiley & Sons, Ltd. [source] Endurance swimming of European eelJOURNAL OF FISH BIOLOGY, Issue 2 2004G. Van Den Thillart A long-term swim trial was performed with five female silver eels Anguilla anguilla of 0·8,1·0 kg (c. 80 cm total length, LT) swimming at 0·5 body lengths (BL) s,1, corresponding to the mean swimming speed during spawning migration. The design of the Blazka-type swim tunnel was significantly improved, and for the first time the flow pattern of a swim tunnel for fish was evaluated with the Laser-Doppler method. The velocity profile over three different cross-sections was determined. It was observed that 80% of the water velocity drop-off occurred over a boundary layer of 20 mm. Therefore, swim velocity errors were negligible as the eels always swam outside this layer. The fish were able to swim continuously day and night during a period of 3 months in the swim tunnel through which fresh water at 19° C was passed. The oxygen consumption rates remained stable at 36·9 ± 2·9 mg O2 kg,1 h,1 over the 3 months swimming period for all tested eels. The mean cost of transportation was 28·2 mg O2 kg,1 km,1. From the total energy consumption the calculated decline in fat content was 30%. When extrapolating to 6000 km this would have been 60%, leaving only 40% of the total energy reserves for reproduction after arriving at the spawning site. Therefore low cost of transport combined with high fat content are crucial for the capacity of the eel to cross the Atlantic Ocean and reproduce. [source] Comparative Energy, Environmental, and Economic Analysis of Traditional and E-commerce DVD Rental NetworksJOURNAL OF INDUSTRIAL ECOLOGY, Issue 3 2007Deepak Sivaraman This study is a comparative life-cycle assessment (LCA) of two competing digital video disc (DVD) rental networks: the e-commerce option, where the customer orders the movies online, and the traditional business option, where the customer goes to the rental store to rent a movie. The analytical framework proposed is for a customer living in the city of Ann Arbor, Michigan in the United States. The primary energy and environmental performance for both networks are presented using a multicriterion LCA. The package selected by the traditional network is responsible for 67% of the difference in total energy consumption of the two alternatives. Results show that the e-commerce alternative consumed 33% less energy and emitted 40% less CO2 than the traditional option. A set of sensitivity analyses test the influence of distance traveled, transportation mode, and reuse of DVD and DVD packaging on the final results. The mode of transportation used by the customer in the traditional business model also affects global emissions and energy consumption. The customer walking to the store is by far the best option in the traditional network; however, the e-commerce option performed comparatively better despite all transportation modes tested. A novel economic indicator, ESAL, is used to compare different transportation modes based on the level of stress exerted on the pavement. The two networks are compared on the basis of cost accounting; consistent with its energy and environmental advantages, the e-commerce network also exerts lesser economic impact, by $1.17, for the functional unit tested. [source] Correlation between energy usage and the rate of economic developmentOPEC ENERGY REVIEW, Issue 1 2006Salman Saif Ghouri This paper reviews the correlation between per capita GDP and per capita consumption of different sources of energy for OPEC Member Countries, the G-7 and three Asian countries, both with and without natural logarithm. In addition, the paper estimates the ratios for total GDP and total energy consumption of different sources of energy and also estimates GDP energy consumption elasticities. The paper concludes that on a per capita basis most OPEC Countries exhibit negative and weak relationships for all forms of energy, including electricity. For the G-7 and Asian countries, this relationship is positive and strong, with the exception of oil for G-7 countries, where there is a weak correlation. Surprisingly, most OPEC Countries showed a comparatively strong and positive correlation when tested for total GDP in relation to total energy consumption of the respective energy sources. The relationship for the rest of the countries remains unchanged. Population might have distorted the results in OPEC Countries. These results suggest that one should be cautious when drawing conclusions and not ignore the aggregate comparison, as this could otherwise lead to wrong results. For G-7 countries, there has been a significant shift in the pattern of energy consumption in relation to GDP when comparing 1960,73 and 1973,2001. All adjusted downward in the later period. However, the greatest adjustment was associated with petroleum consumption. The general conclusion is that wealth creation in G-7 countries is directly associated with the efficient use of all forms of energy. In contrast, most OPEC Countries exhibit a weaker linkage between energy consumption and economic development on a per capita basis, probably due to inefficient usage of resources or due to disproportionate distribution of wealth and thus energy usage. [source] An integrated analysis of prospects for advanced coal-fired power technology in ChinaASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 3 2010Aijun Li Abstract With energy-saving and pollution abatement policy becoming stricter and stronger, advanced coal-fired power technology will undoubtedly play a significant role in China for the new style in industrialization of power industry. In order to forecast coal consumption for power generation from the view of Chinese economic development, firstly this paper simulates total energy consumption and loss during energy transformation in 2030 by computable general equilibrium model. Then power generation by various advanced coal-fired power technologies such as air pollution controlling, green coal-fired power and combined heat and power (CHP) in 2030 is estimated, thus their effects on abatement of air pollution emissions are assessed. Finally, some policy suggestions are given for developing highly efficient and super clean coal-fired power technology in China. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] | ||||||||||||||||