Net load forecasting for high renewable energy penetration grids

International Nuclear Information System (INIS)

Kaur, Amanpreet; Nonnenmacher, Lukas; Coimbra, Carlos F.M.

2016-01-01

We discuss methods for net load forecasting and their significance for operation and management of power grids with high renewable energy penetration. Net load forecasting is an enabling technology for the integration of microgrid fleets with the macrogrid. Net load represents the load that is traded between the grids (microgrid and utility grid). It is important for resource allocation and electricity market participation at the point of common coupling between the interconnected grids. We compare two inherently different approaches: additive and integrated net load forecast models. The proposed methodologies are validated on a microgrid with 33% annual renewable energy (solar) penetration. A heuristics based solar forecasting technique is proposed, achieving skill of 24.20%. The integrated solar and load forecasting model outperforms the additive model by 10.69% and the uncertainty range for the additive model is larger than the integrated model by 2.2%. Thus, for grid applications an integrated forecast model is recommended. We find that the net load forecast errors and the solar forecasting errors are cointegrated with a common stochastic drift. This is useful for future planning and modeling because the solar energy time-series allows to infer important features of the net load time-series, such as expected variability and uncertainty. - Highlights: • Net load forecasting methods for grids with renewable energy generation are discussed. • Integrated solar and load forecasting outperforms the additive model by 10.69%. • Net load forecasting reduces the uncertainty between the interconnected grids.

Assessing the performance of reinforced concrete structures under impact loads

International Nuclear Information System (INIS)

Sharma, Akanshu; Reddy, G.R.; Vaze, K.K.; Ozbolt, Josko; Hofmann, J.

2011-01-01

Reinforced concrete (RC) structures housing nuclear facilities must qualify against much stringent requirements of operating and accidental loads than conventional structures. One such accidental load that must be considered while assessing the performance of safety related RC structures is impact load. It is known that the behavior of concrete/reinforced concrete structures is strongly influenced by the loading rate. The RC structural members subjected to impact loads behave quite differently as compared to the same subjected to quasi-static loading due to the strain-rate influence on strength, stiffness, and ductility as well as to the activation of inertia forces. Moreover, for concrete structures, which exhibit damage and fracture phenomena, the failure mode and cracking pattern depend significantly on loading rate. In general, there is a tendency that with the increase of loading rate the failure mode changes from mode-I to mixed mode. In order to assess the performance of existing structures against impact loads that may be generated mainly due to man-made accidental conditions, it is important to have models that can realistically predict the impact behavior of concrete structures. The present paper focuses on a relatively new approach for 3D finite element analysis of RC structures under impact loads. The approach uses rate sensitive micro-plane model as constitutive law for concrete, while the strain-rate influence is captured by the activation energy. Inertia forces are implicitly accounted for through dynamic finite element analysis. It is shown with the help of different examples that the approach can very well simulate the behavior of RC structural elements under high rate loading. (author)

Targeting Net Zero Energy at Fort Carson: Assessment and Recommendations

Energy Technology Data Exchange (ETDEWEB)

Anderson, K.; Markel, T.; Simpson, M.; Leahey, J.; Rockenbaugh, C.; Lisell, L.; Burman, K.; Singer, M.

2011-10-01

The U.S. Army's Fort Carson installation was selected to serve as a prototype for net zero energy assessment and planning. NREL performed the comprehensive assessment to appraise the potential of Fort Carson to achieve net zero energy status through energy efficiency, renewable energy, and electric vehicle integration. This report summarizes the results of the assessment and provides energy recommendations. This study is part of a larger cross-laboratory effort that also includes an assessment of renewable opportunities at seven other DoD Front Range installations, a microgrid design for Fort Carson critical loads and an assessment of regulatory and market-based barriers to a regional secure smart grid.

Assessment of high temperature nuclear energy storage systems for the production of intermediate and peak-load electric power

International Nuclear Information System (INIS)

Fox, E.C.; Fuller, L.C.; Silverman, M.D.

1977-01-01

Increased cost of energy, depletion of domestic supplies of oil and natural gas, and dependence on foreign suppliers, have led to an investigation of energy storage as a means to displace the use of oil and gas presently being used to generate intermediate and peak-load electricity. Dedicated nuclear thermal energy storage is investigated as a possible alternative. An evaluation of thermal storage systems is made for several reactor concepts and economic comparisons are presented with conventional storage and peak power producing systems. It is concluded that dedicated nuclear storage has a small but possible useful role in providing intermediate and peak-load electric power

Assessment of extreme design loads for modern wind turbines using the probabilistic approach

DEFF Research Database (Denmark)

Abdallah, Imad

There is a large drive to reduce the cost of energy of wind energy generators. Various tracks are being considered such as enhanced O&M strategies through condition monitoring, increased manufacturing efficiency through higher production volumes and increased automation, improved resource...... and drag coefficients showed (a) a tangible reduction in the load partial safety factor for a blade and (b) generally a larger impact on extreme loads during power production compared to stand-still. Therefore, the way forward is for wind turbine manufactures to further update the stochastic model...... assessment through turbine-mounted real-time site assessment technologies, improved components reliability by increased laboratory testing, increased number of prototype test turbines before serial production, larger rotor and tower concepts for both onshore and offshore installations, advanced drive train...

Absorption of short-pulse electromagnetic energy by a resistively loaded straight wire

International Nuclear Information System (INIS)

Miller, E.K.; Deadrick, F.J.; Landt, J.A.

1975-01-01

Absorption of short-pulse electromagnetic energy by a resistively loaded straight wire is examined. Energy collected by the wire, load energy, peak load currents, and peak load voltages are found for a wide range of parameters, with particular emphasis on nuclear electromagnetic pulse (EMP) phenomena. A series of time-sequenced plots is used to illustrate pulse propagation on wires when loads and wire ends are encountered

Comparison of Building Energy Modeling Programs: Building Loads

Energy Technology Data Exchange (ETDEWEB)

Zhu, Dandan [Tsinghua Univ., Beijing (China); Hong, Tianzhen [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Yan, Da [Tsinghua Univ., Beijing (China); Wang, Chuang [Tsinghua Univ., Beijing (China)

2012-06-01

This technical report presented the methodologies, processes, and results of comparing three Building Energy Modeling Programs (BEMPs) for load calculations: EnergyPlus, DeST and DOE-2.1E. This joint effort, between Lawrence Berkeley National Laboratory, USA and Tsinghua University, China, was part of research projects under the US-China Clean Energy Research Center on Building Energy Efficiency (CERC-BEE). Energy Foundation, an industrial partner of CERC-BEE, was the co-sponsor of this study work. It is widely known that large discrepancies in simulation results can exist between different BEMPs. The result is a lack of confidence in building simulation amongst many users and stakeholders. In the fields of building energy code development and energy labeling programs where building simulation plays a key role, there are also confusing and misleading claims that some BEMPs are better than others. In order to address these problems, it is essential to identify and understand differences between widely-used BEMPs, and the impact of these differences on load simulation results, by detailed comparisons of these BEMPs from source code to results. The primary goal of this work was to research methods and processes that would allow a thorough scientific comparison of the BEMPs. The secondary goal was to provide a list of strengths and weaknesses for each BEMP, based on in-depth understandings of their modeling capabilities, mathematical algorithms, advantages and limitations. This is to guide the use of BEMPs in the design and retrofit of buildings, especially to support China’s building energy standard development and energy labeling program. The research findings could also serve as a good reference to improve the modeling capabilities and applications of the three BEMPs. The methodologies, processes, and analyses employed in the comparison work could also be used to compare other programs. The load calculation method of each program was analyzed and compared to

Energy efficiency indicators for high electric-load buildings

Energy Technology Data Exchange (ETDEWEB)

Aebischer, Bernard; Balmer, Markus A.; Kinney, Satkartar; Le Strat, Pascale; Shibata, Yoshiaki; Varone, Frederic

2003-06-01

Energy per unit of floor area is not an adequate indicator for energy efficiency in high electric-load buildings. For two activities, restaurants and computer centres, alternative indicators for energy efficiency are discussed.

Energy conservation prospects through electric load management

Energy Technology Data Exchange (ETDEWEB)

El-Shirbeeny, E H.T.

1984-04-01

In this paper, concepts of electric load management are discussed for effective energy conservation. It is shown that the conservation program must be comprehensive to provide solutions to the problems facing the electric consumer, the electric utility and the society by reducing the rate of growth of energy consumption and power system peak demand requirements. The impact of energy management programs on electric energy conservation is examined, with emphasis on efficiency, storage, cogeneration and controls with computers.

Efficient Energy Consumption Scheduling: Towards Effective Load Leveling

Directory of Open Access Journals (Sweden)

Yuan Hong

2017-01-01

Full Text Available Different agents in the smart grid infrastructure (e.g., households, buildings, communities consume energy with their own appliances, which may have adjustable usage schedules over a day, a month, a season or even a year. One of the major objectives of the smart grid is to flatten the demand load of numerous agents (viz. consumers, such that the peak load can be avoided and power supply can feed the demand load at anytime on the grid. To this end, we propose two Energy Consumption Scheduling (ECS problems for the appliances held by different agents at the demand side to effectively facilitate load leveling. Specifically, we mathematically model the ECS problems as Mixed-Integer Programming (MIP problems using the data collected from different agents (e.g., their appliances’ energy consumption in every time slot and the total number of required in-use time slots, specific preferences of the in-use time slots for their appliances. Furthermore, we propose a novel algorithm to efficiently and effectively solve the ECS problems with large-scale inputs (which are NP-hard. The experimental results demonstrate that our approach is significantly more efficient than standard benchmarks, such as CPLEX, while guaranteeing near-optimal outputs.

Multifunctional Structures for High-Energy Lightweight Load-Bearing Storage

Science.gov (United States)

Loyselle, Patricia L.

2018-01-01

This is a pull-up banner of the Multifunctional Structures for High-Energy Lightweight Load-bearing Storage (M-SHELLS) technology that will be on display at the SciTech Conference in January 2018. Efforts in Multifunctional Structures for High Energy Load-Bearing Storage (M-Shells) are pushing the boundaries of development for hybrid electric propulsion for future commercial aeronautical transport. The M-Shells hybrid material would serve as the power/energy storage of the vehicle and provide structural integrity, freeing up usable volume and mass typically occupied by bulky batteries. The ultimate goal is to demonstrate a system-level mass savings with a multifunctional structure with energy storage.

ENERGY EFFICIENCY DETERMINATION OF LOADING-BACK SYSTEM OF ELECTRIC TRACTION MACHINES

Directory of Open Access Journals (Sweden)

A. M. Afanasov

2014-03-01

Full Text Available Purpose.Acceptance post-repair testsof electric traction machinesare conducted onloading-backstandsthat reducethe overall power costsfor the tests.Currentlya numberof possiblecircuit designs of loading-backsystems of electric machines are known, but there is nomethod of determiningtheir energy efficiency. This in turn makes difficult the choiceof rationaloptions. The purpose of the article is the development of the corresponding methodo-logy to make easier this process. Methodology. Expressions for determining theenergy efficiency ofa stand for testingof electric traction machineswere obtained using the generalizedscheme analysisof energy transformationsin the loading-backsystems of universal structure. Findings.Thetechnique wasoffered and the analytical expressions for determining the energy efficiency of loading-backsystemsof electric traction machines wereobtained. Energy efficiency coefficientofloading-backsystemisproposed to consider as the ratio of the total actionenergy of the mechanical and electromotive forces, providing anchors rotation and flowof currents in electric machines, which are being tested,to the total energy, consumed during the test from the external network. Originality. The concept was introduced and the analytical determination method of the energy efficiency of loading-backsystem in electric traction machines was offered. It differs by efficiency availability of power sources and converters, as well as energy efficiency factors of indirect methods of loss compensation. Practical value. The proposed technique of energy efficiency estimation of a loading-backsystemcan be used in solving the problem of rational options choice of schematics stands decisions for electric traction machines acceptance tests of main line and industrial transport.

Fragility assessment method of Concrete Wall Subjected to Impact Loading

International Nuclear Information System (INIS)

Hahm, Daegi; Shin, Sang Shup; Choi, In-Kil

2014-01-01

These studies have been aimed to verify and ensure the safety of the targeted walls and structures especially in the viewpoint of the deterministic approach. However, recently, the regulation and the assessment of the safety of the nuclear power plants (NPPs) against to an aircraft impact are strongly encouraged to adopt a probabilistic approach, i.e., the probabilistic risk assessment of an aircraft impact. In Korea, research to develop aircraft impact risk quantification technology was initiated in 2012 by Korea Atomic Energy Research Institute (KAERI). In this paper, for the one example of the probabilistic safety assessment approach, a method to estimate the failure probability and fragility of concrete wall subjected to impact loading caused by missiles or engine parts of aircrafts will be introduced. This method and the corresponding results will be used for the total technical roadmap and the procedure to assess the aircraft impact risk (Fig.1). A method and corresponding results of the estimation of the failure probability and fragility for a concrete wall subjected to impact loadings caused by missiles or engine parts of aircrafts was introduced. The detailed information of the target concrete wall in NPP, and the example aircraft engine model is considered safeguard information (SGI), and is not contained in this paper

Supervisory Control of Loads and Energy Storage in Next-Generation Zero Energy Buildings

Energy Technology Data Exchange (ETDEWEB)

Kung, Feitau [National Renewable Energy Lab. (NREL), Golden, CO (United States); Frank, Stephen [National Renewable Energy Lab. (NREL), Golden, CO (United States); Scheib, Jennifer [National Renewable Energy Lab. (NREL), Golden, CO (United States); Bernal Heredia, Willy [National Renewable Energy Lab. (NREL), Golden, CO (United States); Pless, Shanti [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2016-09-01

A zero energy building (ZEB)—also known as a net zero energy or zero net energy building—is a building that exports as much renewable energy as the total energy it imports from other sources on an annual basis (DOE 2015). Large-scale and commercially viable ZEBs are now in the marketplace, and they are expected to become a larger share of the commercial building footprint as government and private sector policies continue to promote the development of buildings that produce more on-site energy than they use. However, the load profiles of ZEBs are currently perceived by electric utilities to be unfavorable and unpredictable. As shown in Figure ES-1, ZEB load profiles can have abrupt changes in magnitude, at times switching rapidly between exporting and importing electricity. This is a challenge for utilities, which are responsible for constantly balancing electricity supply and demand across the grid. Addressing these concerns will require new strategies and tools.

Load Situation Awareness Design for Integration in Multi-Energy System

DEFF Research Database (Denmark)

Cai, Hanmin; You, Shi; Bindner, Henrik W.

2017-01-01

Renewable Energy Sources (RESs) have been penetrating in power system at a staggering pace in recent years. Their intermittent nature is, however, posing great threat to system operation. Recently, active load management has been suggested as a tool to counteract these side effects. In multi......-energy system, thermal load management will benefit not only electric network but also district heating network. Electric heater will be the main focus of this paper as a common thermal load. A situation awareness framework for its integration into electric and district heating network will be proposed...

Analysis of recurrent neural networks for short-term energy load forecasting

Science.gov (United States)

Di Persio, Luca; Honchar, Oleksandr

2017-11-01

Short-term forecasts have recently gained an increasing attention because of the rise of competitive electricity markets. In fact, short-terms forecast of possible future loads turn out to be fundamental to build efficient energy management strategies as well as to avoid energy wastage. Such type of challenges are difficult to tackle both from a theoretical and applied point of view. Latter tasks require sophisticated methods to manage multidimensional time series related to stochastic phenomena which are often highly interconnected. In the present work we first review novel approaches to energy load forecasting based on recurrent neural network, focusing our attention on long/short term memory architectures (LSTMs). Such type of artificial neural networks have been widely applied to problems dealing with sequential data such it happens, e.g., in socio-economics settings, for text recognition purposes, concerning video signals, etc., always showing their effectiveness to model complex temporal data. Moreover, we consider different novel variations of basic LSTMs, such as sequence-to-sequence approach and bidirectional LSTMs, aiming at providing effective models for energy load data. Last but not least, we test all the described algorithms on real energy load data showing not only that deep recurrent networks can be successfully applied to energy load forecasting, but also that this approach can be extended to other problems based on time series prediction.

Assessment of wind turbine load measurement instrumentation

Energy Technology Data Exchange (ETDEWEB)

Morfiadakis, E; Papadopoulos, K [CRES (Greece); Borg, N van der [ECN, Petten (Netherlands); Petersen, S M [Risoe, Roskilde (Denmark); Seifert, H [DEWI, Wilhelmshaven (Germany)

1999-03-01

In the framework of Sub-Task3 `Wind turbine load measurement instrumentation` of EU-project `European Wind Turbine Testing Procedure Development`, the load measurement techniques have been assessed by laboratory, full scale and numerical tests. The existing methods have been reviewed with emphasis on the strain gage application techniques on composite materials and recommendations are provided for the optimisation of load measurement techniques. (au) EU. 14 refs.

Web based system for renewable energy sources assessment

International Nuclear Information System (INIS)

Shtrakov, Stanko; Ivanov, Lachezar South

2011-01-01

The RES A ssess software is developed to assist in the preliminary assessment of potential renewable energy projects. The first release includes water pumping solar systems, passive solar systems, wind, and geothermal energy and biomass. The program guides the users in the design of their systems, by providing initial estimates. By changing the system’s parameters, users are able to quickly screen an effective technology and system size depending on load, climatic conditions, and season of use. This paper describes scope of models (radiation, wind, geothermal, heat transfer) used to predict energy production from energy resource systems, climatic variables and system parameters and software technology for realising the project. Keywords: Energy projects, Renewable energy, Web system

How to count and assess different energies, in particular renewable energies: methodological reflections and examples

International Nuclear Information System (INIS)

Bacher, Pierre

2013-01-01

After having recalled the meaning of the concepts of primary energy and of final energy, as well as their relationships which are conventionally adopted at the international level, the author shows that these concepts are not suitable to the assessment of economic and energetic efficiency of energy systems, notably those comprising several transformations of an energy into another. He also shows that the methodology developed by the Academy of Technologies in its 'Vecteurs' report is perfectly adapted. This is illustrated by two examples: the main uses of biomass, and the use of peak productions of wind energy which is essentially intermittent. With this method, it is possible to identify the main factors which must be quantified when assessing the technical-economic relevance of such or such choice, notably thermodynamic efficiencies of each step, capitals to be invested and expectable load factors, or impact in terms of CO 2 emissions. Appendices proposes energetic statistics for France (energy assessment, consumption of primary energy), an assessment of methanization, and an analysis of wind energy production in Europe while taking its intermittency into account, for the production of hydrogen

Wind loads on solar energy roofs

NARCIS (Netherlands)

Geurts, C.P.W.; Bentum, C.A. van

2007-01-01

This paper presents an overview of the wind loads on roofs, equipped with solar energy products, so called Active Roofs. Values given in this paper have been based on wind tunnel and full scale measurements, carried out at TNO, and on an interpretation of existing rules and guidelines. The results

Emergy-based sustainability assessment of different energy options for green buildings

International Nuclear Information System (INIS)

Luo, Zhiwen; Zhao, Jianing; Yao, Runming; Shu, Zhan

2015-01-01

Highlights: • We apply Emergy to assess environmental impact of different energy options. • We develop a new index to assess the anthropogenic heat emission. • The way of electricity produced is crucial to the total environmental load. • The direct-fired lithium-bromide absorption type shows highest environmental load. - Abstract: It is necessary to minimize the environmental impact and utilize natural resources in a sustainable and efficient manner in the early design stage of developing an environmentally-conscious design for a heating, ventilating and air-conditioning system. Energy supply options play a significant role in the total environmental load of heating, ventilating and air-conditioning systems. To assess the environmental impact of different energy options, a new method based on Emergy Analysis is proposed. Emergy Accounting, was first developed and widely used in the area of ecological engineering, but this is the first time it has been used in building service engineering. The environmental impacts due to the energy options are divided into four categories under the Emergy Framework: the depletion of natural resources, the greenhouse effect (carbon dioxide equivalents), the chemical rain effect (sulfur dioxide equivalents), and anthropogenic heat release. The depletion of non-renewable natural resources is indicated by the Environmental Load Ratio, and the environmental carrying capacity is developed to represent the environmental service to dilute the pollutants and anthropogenic heat released. This Emergy evaluation method provides a new way to integrate different environmental impacts under the same framework and thus facilitates better system choices. A case study of six different kinds of energy options consisting of renewable and non-renewable energy was performed by using Emergy Theory, and thus their relative environmental impacts were compared. The results show that the method of electricity generation in energy sources, especially

Assessment of Replacement Bridge using Proof Load Test

Science.gov (United States)

Sundru, Saibabu

2017-11-01

This work begins with an overview of the condition assessment of old bridge and explained reasons for demolishing of the bridge. Briefly presented flexural analysis of two stage post-tensioned prestressed concrete girder, which will be replace the old (new bridge). Construction of I-girder and composite girder at first stage and second stage prestressing respectively is explained with figures. Assessment of the load-caring capacity of the one span of the replacement bridge with simple supports using proof load test is presented which is mandatory according to Indian standards. Weighted sand bags were used to load the bridge up to a predetermined service load with impact factor. Deflections of the I-girders of the bridge were measured at selected locations along and across the bridge span and compared with computed values. Linear response was observed during loading and unloading. Considering the load test results, theoretical estimation and criteria as stipulated in codes of practice, it can be inferred that prestressed concrete I-girder bridge span has adequate capacity to carry the loads and hence, deemed to have passed the test.

Fast Reliability Assessing Method for Distribution Network with Distributed Renewable Energy Generation

Science.gov (United States)

Chen, Fan; Huang, Shaoxiong; Ding, Jinjin; Ding, Jinjin; Gao, Bo; Xie, Yuguang; Wang, Xiaoming

2018-01-01

This paper proposes a fast reliability assessing method for distribution grid with distributed renewable energy generation. First, the Weibull distribution and the Beta distribution are used to describe the probability distribution characteristics of wind speed and solar irradiance respectively, and the models of wind farm, solar park and local load are built for reliability assessment. Then based on power system production cost simulation probability discretization and linearization power flow, a optimal power flow objected with minimum cost of conventional power generation is to be resolved. Thus a reliability assessment for distribution grid is implemented fast and accurately. The Loss Of Load Probability (LOLP) and Expected Energy Not Supplied (EENS) are selected as the reliability index, a simulation for IEEE RBTS BUS6 system in MATLAB indicates that the fast reliability assessing method calculates the reliability index much faster with the accuracy ensured when compared with Monte Carlo method.

Modeling electric load and water consumption impacts from an integrated thermal energy and rainwater storage system for residential buildings in Texas

International Nuclear Information System (INIS)

Upshaw, Charles R.; Rhodes, Joshua D.; Webber, Michael E.

2017-01-01

Highlights: • Hydronic integrated rainwater thermal storage (ITHERST) system concept presented. • ITHERST system modeled to assess peak electric load shifting and water savings. • Case study shows 75% peak load reduction and 9% increase in energy consumption. • Potable rainwater collection could provide ∼50–90% of water used for case study. - Abstract: The United States’ built environment is a significant direct and indirect consumer of energy and water. In Texas, and other parts of the Southern and Western US, air conditioning loads, particularly from residential buildings, contribute significantly to the peak electricity load on the grid, straining transmission. In parallel, water resources in these regions are strained by growing populations and shrinking supplies. One potential method to address both of these issues is to develop integrated thermal energy and auxiliary water (e.g. rainwater, greywater, etc.) storage and management systems that reduce peak load and freshwater consumption. This analysis focuses on a proposed integrated thermal energy and rainwater storage (ITHERST) system that is incorporated into a residential air-source chiller/heat pump with hydronic distribution. This paper describes a step-wise hourly thermodynamic model of the thermal storage system to assess on-peak performance, and a daily volume-balance model of auxiliary water collection and consumption to assess water savings potential. While the model is generalized, this analysis uses a case study of a single family home in Austin, Texas to illustrate its capabilities. The results indicate this ITHERST system could reduce on-peak air conditioning electric power demand by over 75%, with increased overall electric energy consumption of approximately 7–9%, when optimally sized. Additionally, the modeled rainwater collection reduced municipal water consumption by approximately 53–89%, depending on the system size.

A heuristic-based approach for reliability importance assessment of energy producers

International Nuclear Information System (INIS)

Akhavein, A.; Fotuhi Firuzabad, M.

2011-01-01

Reliability of energy supply is one of the most important issues of service quality. On one hand, customers usually have different expectations for service reliability and price. On the other hand, providing different level of reliability at load points is a challenge for system operators. In order to take reasonable decisions and obviate reliability implementation difficulties, market players need to know impacts of their assets on system and load-point reliabilities. One tool to specify reliability impacts of assets is the criticality or reliability importance measure by which system components can be ranked based on their effect on reliability. Conventional methods for determination of reliability importance are essentially on the basis of risk sensitivity analysis and hence, impose prohibitive calculation burden in large power systems. An approach is proposed in this paper to determine reliability importance of energy producers from perspective of consumers or distribution companies in a composite generation and transmission system. In the presented method, while avoiding immense computational burden, the energy producers are ranked based on their rating, unavailability and impact on power flows in the lines connecting to the considered load points. Study results on the IEEE reliability test system show successful application of the proposed method. - Research highlights: → Required reliability level at load points is a concern in modern power systems. → It is important to assess reliability importance of energy producers or generators. → Generators can be ranked based on their impacts on power flow to a selected area. → Ranking of generators is an efficient tool to assess their reliability importance.

Limit load assessment of centre cracked plates under biaxial loading

International Nuclear Information System (INIS)

Meek, C.; Ainsworth, R.A.

2015-01-01

Fitness-for-service of equipment and components containing defects is generally assessed using procedures such as BS 7910, API 579 and R6. There is currently little detailed advice in these procedures on the effects of biaxial and triaxial loading on fracture. This poster shows some theoretical bounding solutions of the plastic limit load for centre cracked plates under a variety of biaxial loading ratios and compares the estimates with those found by numerical methods using finite element (FE) analysis using Abacus CAE modelling software. The limit load of a structure is the maximum load that it can carry before plastic collapse occurs; this is often when the plastic zone has become large enough to spread from the crack tip to a remote boundary. For an elastic-perfectly plastic material, the irreversible deformation will continue at stresses no higher than the yield stress. The model for these limit load solutions is a bi-axially loaded plate of width 2W and height 2H, a centre crack of width 2a, acted on by remotely applied uniform stresses σ 2 perpendicular to the crack and Bσ 2 parallel to the crack, where B is the biaxial loading ratio, it means the ratio of the parallel to the perpendicular stress. A quarter plate of an elastic-perfectly plastic material has been modelled. The results show that an exact solution has been found for negative and low positive values of B. For B > 1, the lower bound solution is conservative for all values of a/W and B

Development of a method of lifetime assessment of power plant components under complex multi-axial vibration loads

International Nuclear Information System (INIS)

Fesich, Thomas M.

2012-01-01

In general, technical components are loaded and stressed by forces and moments both constant and variable over time. Multi-axial stress conditions can arise as a function of the load on, and/or the geometry of, a component. Assessing the impact on stability of multi-axial stress conditions is a problem for which no generally valid solution has as yet been found, especially when loads and stresses vary over time. This is also due to the fact that the development over time of stresses can give rise to very complex stress conditions. Assessing the lifetime of power plant components subjected to complex vibration loads and stresses often is not reliable if performed by means of conventional codes and approaches, or is associated with high degrees of conservatism. The MPA AIM-Life concept developed at the Stuttgart MPA/IMWF, which is an advanced and verified strength hypothesis based on energy considerations, allows such assessments to be made more reliably, numerically efficient, and avoiding excessive conservatism. (orig.)

Offshore Wind Energy Resource Assessment for Alaska

Energy Technology Data Exchange (ETDEWEB)

Doubrawa Moreira, Paula [National Renewable Energy Lab. (NREL), Golden, CO (United States); Scott, George N. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Musial, Walter D. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Kilcher, Levi F. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Draxl, Caroline [National Renewable Energy Lab. (NREL), Golden, CO (United States); Lantz, Eric J. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2018-01-02

This report quantifies Alaska's offshore wind resource capacity while focusing on its unique nature. It is a supplement to the existing U.S. Offshore Wind Resource Assessment, which evaluated the offshore wind resource for all other U.S. states. Together, these reports provide the foundation for the nation's offshore wind value proposition. Both studies were developed by the National Renewable Energy Laboratory. The analysis presented herein represents the first quantitative evidence of the offshore wind energy potential of Alaska. The technical offshore wind resource area in Alaska is larger than the technical offshore resource area of all other coastal U.S. states combined. Despite the abundant wind resource available, significant challenges inhibit large-scale offshore wind deployment in Alaska, such as the remoteness of the resource, its distance from load centers, and the wealth of land available for onshore wind development. Throughout this report, the energy landscape of Alaska is reviewed and a resource assessment analysis is performed in terms of gross and technical offshore capacity and energy potential.

Impacts of Commercial Building Controls on Energy Savings and Peak Load Reduction

Energy Technology Data Exchange (ETDEWEB)

Fernandez, Nicholas E.P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Katipamula, Srinivas [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wang, Weimin [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Xie, YuLong [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zhao, Mingjie [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Corbin, Charles D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2017-05-30

Commercial buildings in the United States use about 18 Quadrillion British thermal units (Quads) of primary energy annually . Studies have shown that as much as 30% of building energy consumption can be avoided by using more accurate sensing, using existing controls better, and deploying advanced controls; hence, the motivation for the work described in this report. Studies also have shown that 10% to 20% of the commercial building peak load can be temporarily managed/curtailed to provide grid services. Although many studies have indicated significant potential for reducing the energy consumption in commercial buildings, very few have documented the actual savings. The studies that did so only provided savings at the whole building level, which makes it difficult to assess the savings potential of each individual measure deployed.

Low-Load Space Conditioning Needs Assessment

Energy Technology Data Exchange (ETDEWEB)

Puttagunta, Srikanth [Consortium for Advanced Residential Buildings (CARB), Norwalk, CT (United States)

2015-05-19

Heating, ventilating, and air-conditioning (HVAC) equipment must be right-sized to ensure energy performance and comfort. With limited low-load options in the HVAC market, many new-construction housing units are being fitted with oversized equipment that creates system efficiency, comfort, and cost penalties. To bridge the gap between currently available HVAC equipment that is oversized or inefficient and the rising demand for low-load HVAC equipment in the marketplace, HVAC equipment manufacturers need to be fully aware of the needs of the multifamily building and attached single-family (duplex and townhouse) home market. Over the past decade, Steven Winter Associates, Inc. (SWA) has provided certification and consulting services for hundreds of housing projects and has accrued a large pool of data that describe multifamily and attached single-family home characteristics. The U.S. Department of Energy’s Building America research team Consortium for Advanced Residential Buildings (CARB) compiled and analyzed these data to outline the characteristics of low-load dwellings such as the heating and cooling design loads.

A load predictive energy management system for supercapacitor-battery hybrid energy storage system in solar application using the Support Vector Machine

International Nuclear Information System (INIS)

Chia, Yen Yee; Lee, Lam Hong; Shafiabady, Niusha; Isa, Dino

2015-01-01

Highlights: • A novel energy management system (EMS) for supercapacitor-battery hybrid energy storage system is implemented. • It is a load predictive EMS which is implemented using Support Vector Machine (SVM). • An optimum SVM load prediction model is obtained, which yields 100% accuracy in 0.004866 s of training time. • The implemented load predictive EMS is compared with the conventional sequential programming control. • This methodology reduces the number of power electronics used and prolong battery lifespan. - Abstract: This paper presents the use of a Support Vector Machine load predictive energy management system to control the energy flow between a solar energy source, a supercapacitor-battery hybrid energy storage combination and the load. The supercapacitor-battery hybrid energy storage system is deployed in a solar energy system to improve the reliability of delivered power. The combination of batteries and supercapacitors makes use of complementary characteristic that allow the overlapping of a battery’s high energy density with a supercapacitors’ high power density. This hybrid system produces a straightforward benefit over either individual system, by taking advantage of each characteristic. When the supercapacitor caters for the instantaneous peak power which prolongs the battery lifespan, it also minimizes the system cost and ensures a greener system by reducing the number of batteries. The resulting performance is highly dependent on the energy controls implemented in the system to exploit the strengths of the energy storage devices and minimize its weaknesses. It is crucial to use energy from the supercapacitor and therefore minimize jeopardizing the power system reliability especially when there is a sudden peak power demand. This study has been divided into two stages. The first stage is to obtain the optimum SVM load prediction model, and the second stage carries out the performance comparison of the proposed SVM-load predictive

Decrease of dynamic loads in mobile energy means

Science.gov (United States)

Polivaev, O. I.; Gorban, L. K.; Vorohobin, A. V.; Vedrinsky, O. S.

2018-03-01

The increase in the productivity of machine and tractor units is possible due to the increase in operating speeds, this leads to the emergence of increased dynamic loads in the system “engine-transmission-propulsion unit-soil”, which worsens the performance of machine-tractor aggregates. To reduce fluctuations in the “engine-transmission” system, special vibration dampers are used, which installed in close proximity to the engine and protect well the transmission from uneven engine operation; however, such dampers practically do not eliminate the oscillations of external loads. Reducing dynamic loads on the transmission and the mobile power engine (MPE) is an important issue directly related to improving the performance, reliability and durability of the tractor, as well as reducing the slippage of the drive wheels. In order to reduce effectively dynamic loads on the transmission and on the MPE, it is necessary to introduce resilient damping elements closer to the sources of oscillations, namely, to the driving wheels. At the same time, the elastic-damping element should provide accumulation of vibration energy caused by external influences and have a large energy capacity. The installation of an elastic-damping element in the final link of the tractor transmission ensures a reduction in the magnitude of external influences, thereby protecting the engine and transmission from large dynamic loads, and allows one to reduce the slippage of the propellers, which has a positive effect on the traction and energy characteristics of the tractor. Traction tests of the LTP-55 tractor on a concrete road showed that the use of an elasto-damping drive makes it possible to increase the maximum tractive power from 33.5 to 35.3 kW and to reduce the slipping of propellers by 12-30%, the specific fuel consumption by 6-10%. When driving on stubble, the use of an elastic-damping drive increases the maximum tractive power from 25 to 26 kW, reduces the skidding of propellers by

Energy consumption program: A computer model simulating energy loads in buildings

Science.gov (United States)

Stoller, F. W.; Lansing, F. L.; Chai, V. W.; Higgins, S.

1978-01-01

The JPL energy consumption computer program developed as a useful tool in the on-going building modification studies in the DSN energy conservation project is described. The program simulates building heating and cooling loads and computes thermal and electric energy consumption and cost. The accuracy of computations are not sacrificed, however, since the results lie within + or - 10 percent margin compared to those read from energy meters. The program is carefully structured to reduce both user's time and running cost by asking minimum information from the user and reducing many internal time-consuming computational loops. Many unique features were added to handle two-level electronics control rooms not found in any other program.

Economics of Renewable Energy Integration and Energy Storage via Low Load Diesel Application

Directory of Open Access Journals (Sweden)

James Hamilton

2018-04-01

Full Text Available One-quarter of the world’s population lives without access to electricity. Unfortunately, the generation technology most commonly employed to advance rural electrification, diesel generation, carries considerable commercial and ecological risks. One approach used to address both the cost and pollution of diesel generation is renewable energy (RE integration. However, to successfully integrate RE, both the stochastic nature of the RE resource and the operating characteristics of diesel generation require careful consideration. Typically, diesel generation is configured to run heavily loaded, achieving peak efficiencies within 70–80% of rated capacity. Diesel generation is also commonly sized to peak demand. These characteristics serve to constrain the possible RE penetration. While energy storage can relieve the constraint, this adds cost and complexity to the system. This paper identifies an alternative approach, redefining the low load capability of diesel generation. Low load diesel (LLD allows a diesel engine to operate across its full capacity in support of improved RE utilization. LLD uses existing diesel assets, resulting in a reduced-cost, low-complexity substitute. This paper presents an economic analysis of LLD, with results compared to conventional energy storage applications. The results identify a novel pathway for consumers to transition from low to medium levels of RE penetration, without additional cost or system complexity.

Assessment of musculoskeletal load in refuse collectors

Directory of Open Access Journals (Sweden)

Zbigniew W. Jóźwiak

2013-08-01

Full Text Available Background: The aim of this work was to assess the load on the musculoskeletal system and its effects in the collectors of solid refuse. The rationale behind this study was to formulate proposals how to reduce excessive musculoskeletal load in this group of workers. Material and Methods: The study group comprised 15 refuse collectors aged 25 to 50 years. Data about the workplace characteristics and subjective complaints of workers were collected by the free interview and questionnaire. During the survey the photorecording of the workpostures, the distance and velocity by GPS recorders, measurements of forces necessary to move containers, energy expenditure (lung ventilation method, workload estimation using the Firstbeat system and REBA method and stadiometry were done. Results: The distance walked daily by the collectors operating in terms of 2 to 3 in urban areas was about 15 km, and in rural areas about 18 km. The most frequent musculoskeletal complaints concerned the feet (60% subjects, knees, wrists and shoulders (over 40% subjects. After work-shift all examined workers had vertebral column shorter by 10 to 14 mm (11.4 mm mean. Conclusions: The results of our study show that the refuse collectors are subjected to a very high physical load because of the work organization and the way it is performed. To avoid adverse health effects and overload it is necessary to undertake ergonomic interventions, involving training of workers to improve the way of their job performance, active and passive leisure, technical control of the equipment and refuse containers, as well as the renegotiation of contracts with clients, especially those concerning non-standard containers. Med Pr 2013;64(4:507–519

Experimental research of plastic scintillation detector loaded 6Li neutron energy response

International Nuclear Information System (INIS)

Wang Lizong; Zhang Chuanfei; Peng Taiping; Guo Cun; Yang Hongqiong; Zhang Jianhua

2005-01-01

A new plastic scintillator, plastic scintillator loaded 6 Li, is brought forward and developed in this paper in order to increase low energy neutron sensitivity. Neutron sensitivity of several plastic scintillation detectors loaded 6 Li new developed in neutron energy range 0.2 MeV-5.0 MeV are calibrated by direct current at serial accelerator. Energy response curves of the detectors are obtained in this experiment. It is shown that this new plastic scintillation detector can increase low energy neutron sensitivity in experimental results. (authors)

Research on the Operation Mode of Intelligent-town Energy Internet Based on Source-Load Interaction

Science.gov (United States)

Li, Hao; Li, Wen; Miao, Bo; Li, Bin; Liu, Chang; Lv, Zhipeng

2018-01-01

On the background of the rise of intelligence and the increasing deepening of “Internet +”application, the energy internet has become the focus of the energy research field. This paper, based on the fundamental understanding on the energy internet of the intelligent town, discusses the mode of energy supply in the source-load interactive region, and gives an in-depth study on the output characteristics of the energy supply side and the load characteristics of the demand side, so as to derive the law of energy-load interaction of the intelligent-town energy internet.

Importance of nuclear station load factor in applied ro energy policies

International Nuclear Information System (INIS)

Gomes, Daniel de Souza

2015-01-01

Load factor is the ration between the energy produced by a station and the energy it would have produced running at maximum power. The factor intends for all types of commercial reactors. Nuclear plants continuously provide over 11% of the world's electricity. The reactors for which data were available generated 618.7 TWh of electricity in 2014. Typical load factor was around 75% in worldwide during the first quarter of 2015. In this manner, it obtained from an average, three-monthly or yearly. The regular load factor of the reactors in operation was around 56% in 1970. While, in 1980's decade, we have an increase to 63%, the same situation occurred in next the decade and suffering increasing to 73%. Currently, the load factor reaches 78%. Accidents are seasonal factors, with the occurrence of reduction of power generation plants. In 2015 in January, there are over 437 operable commercial reactors in 31 countries, with over 377,728 MWe of full capacity. In Brazil, total capacity is 1901 MWe, with around 2.8% of electricity energy consumed. The primary objective of this study was to find a forecast model that express the evolution of the load factor in the next years. In recent years occur an extensive development of pressurized water reactors in Asia. The periodicity of seasonal effects on the performance of nuclear power plants due to aging. However, the impact of plant age depended on new technologies that allow the growth of the performance. The accident of Fukushima was an inflection point for energy policies. The event produced a trend that reduced the load in the world. (author)

Energy efficiency - The struggle for load management is raging. The French Riviera redoubles savings

International Nuclear Information System (INIS)

Moragues, Manuel; Barla, Jean-Christophe

2014-01-01

A first article discusses the debate initiated by a decree on load management associated with the French Brottes law on energy. Load management is the possibility for consumers to reduce their consumption at peak hours. Electricity producers and suppliers are of course against, whereas new actors (load managers or aggregators) are for. The issue is then to determine who will pay this managed (and not consumed) energy. The article also evokes a controversy about the Brottes law which creates a bonus to subsidy load management, and comments the development of this load management market and its legal framework. A second article describes actions undertaken by industries of the French Riviera to manage their energy consumption

A Smart Load Interface and Voltage Regulator for Electrostatic Vibration Energy Harvester

Science.gov (United States)

Bedier, Mohammed; Basset, Philippe; Galayko, Dimitri

2016-11-01

This paper presents a new implementation in ams 0.35μm HV technology of a complete energy management system for an electrostatic vibrational energy harvester (e-VEH). It is based on the Bennet's doubler architecture and includes a load voltage regulator (LVR) and a smart Load Interface (LI) that are self-controlled with internal voltages for maximum power point tracking (MMPT). The CMOS implementation makes use of an energy harvester that is capable of producing up to 1.8μW at harmonic excitation, given its internal voltage is kept within its optimum. An intermediate LI stage and its controller makes use of a high side switch with zero static power level shifter, and a low power hysteresis comparator. A full circuit level simulation with a VHDL-AMS model of the e-VEH presented was successfully achieved, indicating that the proposed load interface controller consumes less than 100nW average power. Moreover, a LVR regulates the buffer and discharge the harvested energy into a generic resistive load maintaining the voltage within a nominal value of 2 Volts.

Structural Loads Analysis for Wave Energy Converters: Preprint

Energy Technology Data Exchange (ETDEWEB)

van Rij, Jennifer A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Yu, Yi-Hsiang [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Guo, Yi [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2017-08-09

This study explores and verifies the generalized body-modes method for evaluating the structural loads on a wave energy converter (WEC). Historically, WEC design methodologies have focused primarily on accurately evaluating hydrodynamic loads, while methodologies for evaluating structural loads have yet to be fully considered and incorporated into the WEC design process. As wave energy technologies continue to advance, however, it has become increasingly evident that an accurate evaluation of the structural loads will enable an optimized structural design, as well as the potential utilization of composites and flexible materials, and hence reduce WEC costs. Although there are many computational fluid dynamics, structural analyses and fluid-structure-interaction (FSI) codes available, the application of these codes is typically too computationally intensive to be practical in the early stages of the WEC design process. The generalized body-modes method, however, is a reduced order, linearized, frequency-domain FSI approach, performed in conjunction with the linear hydrodynamic analysis, with computation times that could realistically be incorporated into the WEC design process. The objective of this study is to verify the generalized body-modes approach in comparison to high-fidelity FSI simulations to accurately predict structural deflections and stress loads in a WEC. Two verification cases are considered, a free-floating barge and a fixed-bottom column. Details for both the generalized body-modes models and FSI models are first provided. Results for each of the models are then compared and discussed. Finally, based on the verification results obtained, future plans for incorporating the generalized body-modes method into the WEC simulation tool, WEC-Sim, and the overall WEC design process are discussed.

Energy Savings in Cellular Networks Based on Space-Time Structure of Traffic Loads

Science.gov (United States)

Sun, Jingbo; Wang, Yue; Yuan, Jian; Shan, Xiuming

Since most of energy consumed by the telecommunication infrastructure is due to the Base Transceiver Station (BTS), switching off BTSs when traffic load is low has been recognized as an effective way of saving energy. In this letter, an energy saving scheme is proposed to minimize the number of active BTSs based on the space-time structure of traffic loads as determined by principal component analysis. Compared to existing methods, our approach models traffic loads more accurately, and has a much smaller input size. As it is implemented in an off-line manner, our scheme also avoids excessive communications and computing overheads. Simulation results show that the proposed method has a comparable performance in energy savings.

Peak load shifting control using different cold thermal energy storage facilities in commercial buildings: A review

International Nuclear Information System (INIS)

Sun, Yongjun; Wang, Shengwei; Xiao, Fu; Gao, Diance

2013-01-01

Highlights: • Little study reviews the load shifting control using different facilities. • This study reviews load shifting control using building thermal mass. • This study reviews load shifting control using thermal energy storage systems. • This study reviews load shifting control using phase change material. • Efforts for developing more applicable load shifting control are addressed. - Abstract: For decades, load shifting control, one of most effective peak demand management methods, has attracted increasing attentions from both researchers and engineers. Different load shifting control strategies have been developed when diverse cold thermal energy storage facilities are used in commercial buildings. The facilities include building thermal mass (BTM), thermal energy storage system (TES) and phase change material (PCM). Little study has systematically reviewed these load shifting control strategies and therefore this study presents a comprehensive review of peak load shifting control strategies using these thermal energy storage facilities in commercial buildings. The research and applications of the load shifting control strategies are presented and discussed. The further efforts needed for developing more applicable load shifting control strategies using the facilities are also addressed

Beam loading in high-energy storage rings

International Nuclear Information System (INIS)

Wilson, P.B.

1974-06-01

The analysis of beam loading in the RF systems of high-energy storage rings (for example, the PEP e/sup /minus//e/sup +/ ring) is complicated by the fact that the time, T/sub b/, between the passage of successive bunches is comparable to the cavity filling time, T/sub b/. In this paper, beam loading expressions are first summarized for the usual case in which T/sub b/ /much lt/ T/sub f/. The theory of phase oscillations in the heavily-beam-loaded case is considered, and the dependence of the synchrotron frequency and damping constant for the oscillations on beam current and cavity tuning is calculated. Expressions for beam loading are then derived which are valid for any value of the ratio T/sub b//T/sub f/. It is shown that, for the proposed PEP e/sup /minus//e/sup +/ ring parameters, the klystron power required is increased by about 3% over that calculated using the standard beam loading expressions. Finally, the analysis is extended to take into account the additional losses associated with the excitation of higher-order cavity modes. A rough numerical estimate is made of the loss enhancement to be expected for PEP RF system. It is concluded that this loss enhancement might be substantial unless appropriate measures are taken in the design and tuning of the accelerating structure

Technical and economic assessment of fluidized bed augmented compressed air energy storage system. Volume III. Preconceptual design

Energy Technology Data Exchange (ETDEWEB)

Giramonti, A.J.; Lessard, R.D.; Merrick, D.; Hobson, M.J.

1981-09-01

A technical and economic assessment of fluidized bed combustion augmented compressed air energy storage systems is presented. The results of this assessment effort are presented in three volumes. Volume III - Preconceptual Design contains the system analysis which led to the identification of a preferred component configuration for a fluidized bed combustion augmented compressed air energy storage system, the results of the effort which transformed the preferred configuration into preconceptual power plant design, and an introductory evaluation of the performance of the power plant system during part-load operation and while load following.

Assessing and Reducing Plug and Process Loads in Retail Buildings (Brochure)

Energy Technology Data Exchange (ETDEWEB)

2011-06-01

Plug and process loads (PPLs) in commercial buildings account for almost 5% of U.S. primary energy consumption. Minimizing these loads is a primary challenge in the design and operation of an energy-efficient building. PPLs are not related to general lighting, heating, ventilation, cooling, and water heating, and typically do not provide comfort to the occupants. They use an increasingly large fraction of the building energy use pie because the number and variety of electrical devices have increased along with building system efficiency. Reducing PPLs is difficult because energy efficiency opportunities and the equipment needed to address PPL energy use in retail spaces are poorly understood.

Assessing and Reducing Plug and Process Loads in Office Buildings (Brochure)

Energy Technology Data Exchange (ETDEWEB)

2011-06-01

Plug and process loads (PPLs) in commercial buildings account for almost 5% of U.S. primary energy consumption. Minimizing these loads is a primary challenge in the design and operation of an energy-efficient building. PPLs are not related to general lighting, heating, ventilation, cooling, and water heating, and typically do not provide comfort to the occupants. They use an increasingly large fraction of the building energy use pie because the number and variety of electrical devices have increased along with building system efficiency. Reducing PPLs is difficult because energy efficiency opportunities and the equipment needed to address PPL energy use in office spaces are poorly understood.

Assessing Power System Stability Following Load Changes and Considering Uncertainty

Directory of Open Access Journals (Sweden)

D. V. Ngo

2018-04-01

Full Text Available An increase in load capacity during the operation of a power system usually causes voltage drop and leads to system instability, so it is necessary to monitor the effect of load changes. This article presents a method of assessing the power system stability according to the load node capacity considering uncertainty factors in the system. The proposed approach can be applied to large-scale power systems for voltage stability assessment in real-time.

Fatigue Crack Propagation Under Variable Amplitude Loading Analyses Based on Plastic Energy Approach

Directory of Open Access Journals (Sweden)

Sofiane Maachou

2014-04-01

Full Text Available Plasticity effects at the crack tip had been recognized as “motor” of crack propagation, the growth of cracks is related to the existence of a crack tip plastic zone, whose formation and intensification is accompanied by energy dissipation. In the actual state of knowledge fatigue crack propagation is modeled using crack closure concept. The fatigue crack growth behavior under constant amplitude and variable amplitude loading of the aluminum alloy 2024 T351 are analyzed using in terms energy parameters. In the case of VAL (variable amplitude loading tests, the evolution of the hysteretic energy dissipated per block is shown similar with that observed under constant amplitude loading. A linear relationship between the crack growth rate and the hysteretic energy dissipated per block is obtained at high growth rates. For lower growth rates values, the relationship between crack growth rate and hysteretic energy dissipated per block can represented by a power law. In this paper, an analysis of fatigue crack propagation under variable amplitude loading based on energetic approach is proposed.

Load Reduction, Demand Response and Energy Efficient Technologies and Strategies

Energy Technology Data Exchange (ETDEWEB)

Boyd, Paul A.; Parker, Graham B.; Hatley, Darrel D.

2008-11-19

The Department of Energy’s (DOE’s) Pacific Northwest National Laboratory (PNNL) was tasked by the DOE Office of Electricity (OE) to recommend load reduction and grid integration strategies, and identify additional demand response (energy efficiency/conservation opportunities) and strategies at the Forest City Housing (FCH) redevelopment at Pearl Harbor and the Marine Corps Base Hawaii (MCBH) at Kaneohe Bay. The goal was to provide FCH staff a path forward to manage their electricity load and thus reduce costs at these FCH family housing developments. The initial focus of the work was at the MCBH given the MCBH has a demand-ratchet tariff, relatively high demand (~18 MW) and a commensurate high blended electricity rate (26 cents/kWh). The peak demand for MCBH occurs in July-August. And, on average, family housing at MCBH contributes ~36% to the MCBH total energy consumption. Thus, a significant load reduction in family housing can have a considerable impact on the overall site load. Based on a site visit to the MCBH and meetings with MCBH installation, FCH, and Hawaiian Electric Company (HECO) staff, recommended actions (including a "smart grid" recommendation) that can be undertaken by FCH to manage and reduce peak-demand in family housing are made. Recommendations are also made to reduce overall energy consumption, and thus reduce demand in FCH family housing.

Estimation of metal pollutant loads from Nuclear and Energy Research Institute (Brazil)

Energy Technology Data Exchange (ETDEWEB)

Marques, Joyce R.; Monteiro, Lucilena R.; Soares, Sabrina M.V.; Stellato, Thamiris B.; Silva, Tatiane B.S.C.; Silva, Douglas B. da; Faustino, Mainara G.; Pires, Maria A.F.; Cotrim, Marycel E.B., E-mail: joyce.marques@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2015-07-01

According to National Environmental Council's (CONAMA) Resolution 357/05, pollutant load can be defined as the amount of a particular pollutant released in receiving water body; it is commonly expressed in a mass-time ratio. As specified in CONAMA's Resolution 430/11, the responsible for the pollutant source must present the Pollutant Load Declaration to environmental authorities. However, pollutant load knowledge is also important to the water quality maintenance and its environmental rating that must be kept to meet the requirements of the most restrictive use. In the control of metals releases is also important due public health matters, since they can cause harmful environmental contamination and major public health issues. Therefore this work aims to present the estimated metal pollutant load released by Nuclear and Energy Research Institute (IPEN/CNEN - Brazil), between 2013 and 2014. Results of cadmium, lead, copper, chromium, zinc, nickel, manganese, iron, barium, silver, boron and tin in composite samples (weekly) via Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and bromide (Br-) released as a tracer, to measure the wastewater flow were used to estimate IPEN's Metal Pollutant load. This study is part of the environmental assessment Program at IPEN, instituted since 2006 to the attendance of the current environmental legislation (CONAMA's Resolution 430/11, Article 19-A of State Decree 8.468/76 and State Decree 15.425/80). (author)

Energy assessments

International Nuclear Information System (INIS)

Unruh, T.D.

1998-01-01

Energy industry initiatives during the 1970s and during the 1990s are compared. During the 1970s, the objective was to reduce energy consumption and to reduce dependency on foreign fuel. Today, the emphasis is on reducing energy costs and to improve net operating income. The challenges posed by the drive to reduce energy costs are discussed. As a tool in the drive to reduce energy cost, the energy assessment process was described. The process entails a detailed analysis of energy consumption, an investigation of energy rates and an assessment of site conditions and equipment, with a view towards an optimum combination that will lead to energy cost reductions

Electric utility load management: rational use of energy program pilot study

Energy Technology Data Exchange (ETDEWEB)

1977-08-01

In recognition of the role that load management can play in ensuring that the growing demand for electricity is met in a cost- and energy-efficient manner, in mid-1974, the NATO Committee on the Challenges of Modern Society sponsored all three meetings to provide a forum for representatives of U.S. and European utilities to exchange views and experiences on the various aspects of load management. It was the consensus of representatives at the meetings that three overall approaches offer significant opportunities for achieving improved load management: development of marginal-cost rate structures; power pooling and energy storage by utilities; and efforts by consumers. Industrial consumers can assist electric utilities in their efforts to level system loads through three important methods: interruptible power and deferred load control; peak self-generation; and shifts in operating schedules. Residential/commercial consumers also have an important role to play by managing both their electric heating load (through the interruption of direct-resistance heating and the storage of heat) and their air conditioning load. In response to the interest expressed by the participants in the CCMS conferences, the U.S. and several European governments, national electric utility industry organizations, state public utility commissions, and many individual utilities have undertaken R and D projects to investigate and test various aspects of these three approaches to load management. This report describes the projects that were presented by the utility representatives.

Inclusion of Structural Flexibility in Design Load Analysis for Wave Energy Converters: Preprint

Energy Technology Data Exchange (ETDEWEB)

Guo, Yi [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Yu, Yi-Hsiang [National Renewable Energy Laboratory (NREL), Golden, CO (United States); van Rij, Jennifer A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Tom, Nathan M [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2017-08-14

Hydroelastic interactions, caused by ocean wave loading on wave energy devices with deformable structures, are studied in the time domain. A midfidelity, hybrid modeling approach of rigid-body and flexible-body dynamics is developed and implemented in an open-source simulation tool for wave energy converters (WEC-Sim) to simulate the dynamic responses of wave energy converter component structural deformations under wave loading. A generalized coordinate system, including degrees of freedom associated with rigid bodies, structural modes, and constraints connecting multiple bodies, is utilized. A simplified method of calculating stress loads and sectional bending moments is implemented, with the purpose of sizing and designing wave energy converters. Results calculated using the method presented are verified with those of high-fidelity fluid-structure interaction simulations, as well as low-fidelity, frequency-domain, boundary element method analysis.

Microcogeneration in buildings with low energy demand in load sharing application

International Nuclear Information System (INIS)

Angrisani, Giovanni; Canelli, Michele; Roselli, Carlo; Sasso, Maurizio

2015-01-01

Highlights: • The use of microcogenerator (MCHP) in buildings with low energy demand is evaluated. • The load sharing approach leads to suitable thermal and electric loads for MCHP. • Dynamic simulations are carried out considering two different climates. • A sensitivity analysis with respect to the self-consumed electricity is performed. • MCHPs with internal combustion engine perfectly match with well-insulated buildings. - Abstract: The paper investigates the introduction of a MCHP (Micro Combined Heat and Power) system in buildings with low energy demand with respect to the current building stock. A load sharing approach between a multifamily residential building and an office one is taken into account. Dynamic simulations are carried out in order to evaluate the thermo-economic performance of the analyzed system. Particular attention is given to the estimation of the electric load of the different users, as the economic profitability of a MCHP system is strongly influenced by the amount of self-consumed electricity. In order to analyze the influence of climatic conditions, two different geographical locations in Italy (Naples and Turin, having 1034 and 2617 heating degree days, respectively) are considered. The results of this study indicate that the installation of MCHP systems in buildings with low energy demand allows to increase the percentage of self-consumed electricity reducing the bidirectional electricity flow between the users and the external grid, as well as the impact on the grid itself due to the large diffusion of distributed generation systems. Moreover this study shows that the load sharing approach between users with different load profile leads to better energy, environmental and economic results with respect to a conventional system. The climatic conditions play an important role on the MCHP operational hours and hence on the thermo-economic performance of the system. The primary energy saving of the system located in Turin is

Effect of Islanding and Telecontrolled Switches on Distribution System Reliability Considering Load and Green-Energy Fluctuations

Directory of Open Access Journals (Sweden)

Stefania Conti

2016-05-01

Full Text Available To improve electrical distribution network reliability, some portions of the network could operate in autonomous mode, provided that the related technical issues are addressed. More specifically, when there is not a path from those portions to the primary substation due to a fault in the network, such portions could be disconnected from the main network and supplied by local generation only. Such a mode of operation is known as “intentional islanding” and its effectiveness, in terms of adequacy, depends on the ability of the local generation to meet the island’s load. In fact, the ratio between the available local generation and load demand can frequently change during islanding due to load variations and, especially, due to the strongly irregular behavior of the primary energy sources of renewable generators. This paper proposes an analytical formulation to assess local generation adequacy during intentional islanding, accounting for the aforementioned variations. More specifically, the fluctuations of load and green-energy generators during islanding are modeled by means of Markov chains, whose output quantities are encompassed in the proposed analytical formulation. Such a formulation is used by the analytical equations of load points’ outage rate and duration. The evaluation of the reliability indices accounts for a protection scheme based on an appropriate communication infrastructure. Therefore, a brief overview on the telecommunications technologies has been presented with reference to their suitability for the specific application. In particular, distribution network safety issues have been considered as the main concern. The results show that neglecting load and generation fluctuations leads to a strong overestimation of the ability of distributed generators to meet the island load. Through a case study it is observed that the error on the load point outage rate is greater than the one affecting the outage duration.

Robust Building Energy Load Forecasting Using Physically-Based Kernel Models

Directory of Open Access Journals (Sweden)

Anand Krishnan Prakash

2018-04-01

Full Text Available Robust and accurate building energy load forecasting is important for helping building managers and utilities to plan, budget, and strategize energy resources in advance. With recent prevalent adoption of smart-meters in buildings, a significant amount of building energy consumption data became available. Many studies have developed physics-based white box models and data-driven black box models to predict building energy consumption; however, they require extensive prior knowledge about building system, need a large set of training data, or lack robustness to different forecasting scenarios. In this paper, we introduce a new building energy forecasting method based on Gaussian Process Regression (GPR that incorporates physical insights about load data characteristics to improve accuracy while reducing training requirements. The GPR is a non-parametric regression method that models the data as a joint Gaussian distribution with mean and covariance functions and forecast using the Bayesian updating. We model the covariance function of the GPR to reflect the data patterns in different forecasting horizon scenarios, as prior knowledge. Our method takes advantage of the modeling flexibility and computational efficiency of the GPR while benefiting from the physical insights to further improve the training efficiency and accuracy. We evaluate our method with three field datasets from two university campuses (Carnegie Mellon University and Stanford University for both short- and long-term load forecasting. The results show that our method performs more accurately, especially when the training dataset is small, compared to other state-of-the-art forecasting models (up to 2.95 times smaller prediction error.

Research on Energy-Saving Design of Overhead Travelling Crane Camber Based on Probability Load Distribution

Directory of Open Access Journals (Sweden)

Tong Yifei

2014-01-01

Full Text Available Crane is a mechanical device, used widely to move materials in modern production. It is reported that the energy consumptions of China are at least 5–8 times of other developing countries. Thus, energy consumption becomes an unavoidable topic. There are several reasons influencing the energy loss, and the camber of the girder is the one not to be neglected. In this paper, the problem of the deflections induced by the moving payload in the girder of overhead travelling crane is examined. The evaluation of a camber giving a counterdeflection of the girder is proposed in order to get minimum energy consumptions for trolley to move along a nonstraight support. To this aim, probabilistic payload distributions are considered instead of fixed or rated loads involved in other researches. Taking 50/10 t bridge crane as a research object, the probability loads are determined by analysis of load distribution density functions. According to load distribution, camber design under different probability loads is discussed in detail as well as energy consumptions distribution. The research results provide the design reference of reasonable camber to obtain the least energy consumption for climbing corresponding to different P0; thus energy-saving design can be achieved.

Short-Term Load Forecast in Electric Energy System in Bulgaria

Directory of Open Access Journals (Sweden)

Irina Asenova

2010-01-01

Full Text Available As the accuracy of the electricity load forecast is crucial in providing better cost effective risk management plans, this paper proposes a Short Term Electricity Load Forecast (STLF model with high forecasting accuracy. Two kind of neural networks, Multilayer Perceptron network model and Radial Basis Function network model, are presented and compared using the mean absolute percentage error. The data used in the models are electricity load historical data. Even though the very good performance of the used model for the load data, weather parameters, especially the temperature, take important part for the energy predicting which is taken into account in this paper. A comparative evaluation between a traditional statistical method and artificial neural networks is presented.

Guideline for load and resistance assessment of existing european railway bridges

OpenAIRE

JENSEN, Jens S; CASAS, Joan R; KAROUMI, Raid; PLOS, Mario; CREMONA, Christian; MELBOURNE, Clive

2008-01-01

Many of the European railway bridges are getting close to the end of their service life. At the same time the railway operators demand higher axle loads for freight trains and higher speeds for passenger trains. This requires new and better approaches for assessing both the railway loads and the resistance of railway bridges. The main objective of the "Guideline for Load and Resistance Assessment of Existing European Railway Bridges", developed within EU founded project "Sustainable Bridge...

Equivalent full-load hours for assessing climate change impact on building cooling and heating energy consumption in large Asian cities

International Nuclear Information System (INIS)

Spandagos, Constantinos; Ng, Tze Ling

2017-01-01

Highlights: • EFLH for estimating cooling/heating energy demand in Asian buildings are provided. • Net increases in building energy consumption over the next 30 years are predicted. • Switching to more efficient AC devices can offset much of the increases. - Abstract: Estimating cooling and heating energy requirements is an integral part of designing and managing buildings. Further, as buildings are among the largest energy consumers in cities, the estimates are important for formulating effective energy conservation strategies. Where complex hourly simulation models are not favored, such estimates may be derived by simplified methods that are less computationally intensive but still provide results that are reasonably close to those obtained from the more complicated approach. The equivalent full load hours (EFLH) method is a simplified energy estimation method that has recently gained popularity. It offers a straightforward means of evaluating energy efficiency programs. However, to date, easily accessible EFLH data exist only for a very limited number of countries in North America and Europe, but not Asia. This current work provides previously unavailable monthly EFLH data for building cooling and heating in three large Asian cities, viz. Hong Kong, Seoul and Tokyo. To assess the effects of changing temperature over the course of decades on building cooling and heating energy consumption, EFLH data are calculated for three time periods: past (1983–2005), present (2006–2014) and future (2015–2044). The projections for the future time period are based on the climate scenarios Representative Concentration Pathways (RCPs) 4.5 and 8.5 of the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report. RCP-4.5 assumes a stabilization of future greenhouse gas (GHG) emissions followed by a reduction, while RCP-8.5 assumes their further increase. From the EFLH data, considering just the effects of ambient temperature changes, it is projected the

Wave Induced Loads on the LEANCON Wave Energy Converter

DEFF Research Database (Denmark)

Frigaard, Peter; Kofoed, Jens Peter; Beserra, Eliab Ricarte

This report is a product of the co-operation agreement between Aalborg University and LEANCON (by Kurt Due Rasmussen) on the evaluation and development of the LEANCON wave energy converter (WEC). The work reported here has focused on evaluation of the wave induced loads on the device, based...... in the laboratory, all under the supervision of the personnel of the Wave Energy Research Group at Department of Civil Engineering, Aalborg University....

Impacts of Using Distributed Energy Resources to Reduce Peak Loads in Vermont

Energy Technology Data Exchange (ETDEWEB)

Ruth, Mark F. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Lunacek, Monte S. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Jones, Birk [Univ. of New Mexico, Albuquerque, NM (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-11-28

To help the United States develop a modern electricity grid that provides reliable power from multiple resources as well as resiliency under extreme conditions, the U.S. Department of Energy (DOE) is leading the Grid Modernization Initiative (GMI) to help shape the future of the nation's grid. Under the GMI, DOE funded the Vermont Regional Initiative project to provide the technical support and analysis to utilities that need to mitigate possible impacts of increasing renewable generation required by statewide goals. Advanced control of distributed energy resources (DER) can both support higher penetrations of renewable energy by balancing controllable loads to wind and photovoltaic (PV) solar generation and reduce peak demand by shedding noncritical loads. This work focuses on the latter. This document reports on an experiment that evaluated and quantified the potential benefits and impacts of reducing the peak load through demand response (DR) using centrally controllable electric water heaters (EWHs) and batteries on two Green Mountain Power (GMP) feeders. The experiment simulated various hypothetical scenarios that varied the number of controllable EWHs, the amount of distributed PV systems, and the number of distributed residential batteries. The control schemes were designed with several objectives. For the first objective, the primary simulations focused on reducing the load during the independent system operator (ISO) peak when capacity charges were the primary concern. The second objective was to mitigate DR rebound to avoid new peak loads and high ramp rates. The final objective was to minimize customers' discomfort, which is defined by the lack of hot water when it is needed. We performed the simulations using the National Renewable Energy Laboratory's (NREL's) Integrated Energy System Model (IESM) because it can simulate both electric power distribution feeder and appliance end use performance and it includes the ability to simulate

Critical loads - assessment of uncertainty

Energy Technology Data Exchange (ETDEWEB)

Barkman, A.

1998-10-01

The effects of data uncertainty in applications of the critical loads concept were investigated on different spatial resolutions in Sweden and northern Czech Republic. Critical loads of acidity (CL) were calculated for Sweden using the biogeochemical model PROFILE. Three methods with different structural complexity were used to estimate the adverse effects of S0{sub 2} concentrations in northern Czech Republic. Data uncertainties in the calculated critical loads/levels and exceedances (EX) were assessed using Monte Carlo simulations. Uncertainties within cumulative distribution functions (CDF) were aggregated by accounting for the overlap between site specific confidence intervals. Aggregation of data uncertainties within CDFs resulted in lower CL and higher EX best estimates in comparison with percentiles represented by individual sites. Data uncertainties were consequently found to advocate larger deposition reductions to achieve non-exceedance based on low critical loads estimates on 150 x 150 km resolution. Input data were found to impair the level of differentiation between geographical units at all investigated resolutions. Aggregation of data uncertainty within CDFs involved more constrained confidence intervals for a given percentile. Differentiation as well as identification of grid cells on 150 x 150 km resolution subjected to EX was generally improved. Calculation of the probability of EX was shown to preserve the possibility to differentiate between geographical units. Re-aggregation of the 95%-ile EX on 50 x 50 km resolution generally increased the confidence interval for each percentile. Significant relationships were found between forest decline and the three methods addressing risks induced by S0{sub 2} concentrations. Modifying S0{sub 2} concentrations by accounting for the length of the vegetation period was found to constitute the most useful trade-off between structural complexity, data availability and effects of data uncertainty. Data

Load following generation in nuclear power plants by latent thermal energy storage

International Nuclear Information System (INIS)

Abe, Yoshiyuki; Takahashi, Yoshio; Kamimoto, Masayuki; Sakamoto, Ryuji; Kanari, Katsuhiko; Ozawa, Takeo

1985-01-01

The recent increase in nuclear power plants and the growing difference between peak and off-peak demands imperatively need load following generation in nuclear power plants to meet the time-variant demands. One possible way to resolve the problem is, obviously, a prompt reaction conrol in the reactors. Alternatively, energy storage gives another sophisticated path to make load following generation in more effective manner. Latent thermal energy storage enjoys high storage density and allows thermal extraction at nearly constant temperature, i.e. phase change temperature. The present report is an attempt to evaluate the feasibility of load following electric power generation in nuclear plants (actually Pressurized Water Reactors) by latent thermal energy storage. In this concept, the excess thermal energy in the off-peak period is stored in molten salt latent thermal energy storage unit, and additional power output is generated in auxiliary generator in the peak demand duration using the stored thermal energy. The present evaluation gives encouraging results and shows the primary subject to be taken up at first is the compatibility of candidate storage materials with inexpensive structural metal materials. Chapter 1 denotes the background of the present report, and Chapter 2 reviews the previous studies on the peak load coverage by thermal energy storage. To figure out the concept of the storage systems, present power plant systems and possible constitution of storage systems are briefly shown in Chapter 3. The details of the evaluation of the candidate storage media, and the compilation of the materials' properties are presented in Chapter 4. In Chapter 5, the concept of the storage systems is depicted, and the economical feasibility of the systems is evaluated. The concluding remarks are summarized in Chapter 6. (author)

Integrated biomass and solar town: Incorporation of load shifting and energy storage

International Nuclear Information System (INIS)

Hashim, Haslenda; Ho, Wai Shin; Lim, Jeng Shiun; Macchietto, Sandro

2014-01-01

The IBS (Integrated Biomass Solar) town is a concept which encourages local community to utilize biomass waste comprehensively with strong ties between community and local stakeholders. This paper discusses an IBS model and solution for an electrically self-sufficient eco-village with and without LS (load shifting). ES (energy storage) is also incorporated to help reduce electricity demand during peak periods and smooth variations in power generation by variable generation of solar power. Application to a realistic case study shows that substantial technical and economic benefits are achieved through the implementation of IBS with LS and ES. In this study, the LS is used mainly to increase demand during periods of high supply and also shift the load to intervals with low demand. This reduces the size of ES significantly, where the load is subject to distinct weekday and weekend profiles. The study shows that highly competitive electricity prices are obtained and the concept offers the opportunity to spur economic growth and environmental protection through energy efficiency improvement and deployment of low-carbon technologies. - Highlights: • A hybrid energy system for designing and optimizing RE resource utilization. • The load shifting and energy storage are incorporated. • The proposed model is demonstrated on an Iskandar Malaysia case study. • The optimal power generation scheme and power generation schedule are determined

Energy transfer from a superconducting magnet to an inductive load

International Nuclear Information System (INIS)

Onishi, Toshitada; Miura, Akinori.

1977-01-01

Experiments on energy transfer between two superconducting magnets have been carried out using an inductive energy transfer system similar to the flying capacitor system developed at the Karlsruhe Institute. In the present system the capacitor is grounded and diodes are used instead of thyristors, and a fraction of stored energy is transferred to the capacitor only when the relay connected in parallel to the magnet is switched off. The capacitor is expected to have no constraint in size, while in the flying capacitor system the capacitor is required to exceed a threshold size. Consequently it is possible to shorten the transfer time to some extent in comparison with the one in the flying capacitor system. Transfer experiments have been carried out using a storage magnet with inductance of 1.2H and a load of 0.41H. The capacitance is 200μF. It is possible to transfer 80.1% of the stored energy of 221 J into the load in less than about 0.35 seconds. (auth.)

Energy cost and mechanical work of walking during load carriage in soldiers.

Science.gov (United States)

Grenier, Jordane G; Peyrot, Nicolas; Castells, Josiane; Oullion, Roger; Messonnier, Laurent; Morin, Jean-Benoit

2012-06-01

In the military context, soldiers carry equipments of total mass often exceeding 30%-40% of their body mass (BM) and complexly distributed around their body (backpack, weapons, electronics, protections, etc.), which represents severe load carrying conditions. This study aimed to better understand the effects of load carriage on walking energetics and mechanics during military-type walking. Ten male infantrymen recently retired from the French Foreign Legion performed 3-min walking trials at a constant speed of 4 km·h(-1) on an instrumented treadmill, during which walking pattern spatiotemporal parameters, energy cost (C(W)), external mechanical work (W(ext)), and the work done by one leg against the other during the double-contact period (W(int,dc)) were specifically assessed. Three conditions were tested: (i) light sportswear (SP, reference condition considered as unloaded), (ii) battle equipment (BT, ∼22 kg, ∼27% of subjects' BM, corresponding to a military intermediate load), and (iii) road march equipment (RM, ∼38 kg, ∼46% of subjects' BM, corresponding to a military high load). Repeated-measures ANOVA showed that military equipment carriage significantly (i) altered the spatiotemporal pattern of walking (all P < 0.01), (ii) increased absolute gross and net CW (P < 0.0001), and (iii) increased both absolute and mass-relative W(ext) (P < 0.01) and W(int,dc) (P < 0.0001) but did not alter the inverted pendulum recovery or locomotor efficiency. Military equipments carriage induced significant changes in walking mechanics and energetics, but these effects appeared not greater than those reported with loads carried around the waist and close to the center of mass. This result was not expected because the latter has been hypothesized to be the optimal method of load carriage from a metabolic standpoint.

Postural loading assessment in assembly workers of an Iranian telecommunication manufacturing company.

Science.gov (United States)

Kamalinia, Mojtaba; Nasl Saraji, Gebreal; Kee, Dohyung; Hosseini, Mostafa; Choobineh, Alireza

2013-01-01

Changes in industries and work practices have coincided with work-related musculoskeletal disorders (MSDs). This study was conducted to determine the prevalence of MSDs and to assess postural loading in assembly workers of an Iranian telecommunication manufacturing company. Data were collected from 193 randomly selected workers in 4 units of the company. The Nordic musculoskeletal disorders questionnaire and the UBC ergonomic checklist were used as data collection tools. Loading on the upper body assessment (LUBA) was used to assess postural loading. Lower back symptoms were the most prevalent problems among the workers (67.9%). LUBA showed that most assembly workers (94.3%) had experienced considerable and high postural loading (postural load index, PLI > 5). Regression analyses revealed that lighting, rotation, contact stress, repetition, gender and age were factors associated with symptoms. Work-related MSDs occurred at a high rate among workers. Postural loading requires consideration. Any ergonomic intervention should focus on eliminating ergonomic factors associated with symptoms.

Structural assessment of TAPS core shroud under accident loads

International Nuclear Information System (INIS)

Bhasin, Vivek; Kushwaha, H.S.; Mahajan, S.C.; Kakodkar, A.

1996-09-01

Over the last few years, the Core Shroud of Boiling Water Reactors (BWRs) operating in foreign countries, have developed cracks at weld locations. As a first step for assessment of structural safety of Tarapur Atomic Power Station (TAPS) core shroud, its detailed stress analysis was done for postulated accident loads. This report is concerned with structural assessment of core shroud, of BWR at TAPS, subjected to loads resulting from main steam line break (MSLB), recirculation line break (RLB) and safe shut down earthquake. The stress analysis was done for core shroud in healthy condition and without any crack since, visual examination conducted till now, do not indicate presence of any flaw. Dynamic structural analysis for MSLB and RLB events was done using dynamic load factor (DLF) method. The complete core shroud and its associated components were modelled and analysed using 3D plate/shell elements. Since, the components of core shroud are submerged in water, hence, hydrodynamic added mass was also considered for evaluation of natural frequencies. It was concluded that from structural point of view, adequate safety margin is available under all the accident loads. Nonlinear analysis was done to evaluate buckling/collapse load. The collapse/buckling load have sufficient margin against the allowable limits. The displacements are low hence, the insertion of control rod may not be affected. (author)

Energy Saving Assessment of Semi-Transparent Photovoltaic Modules Integrated into NZEB

Directory of Open Access Journals (Sweden)

Cristina Cornaro

2017-01-01

Full Text Available Photovoltaic semi-transparent materials (STPV integrated into glazing systems can offer good potential for energy saving to buildings, influencing heating loads, cooling loads, and lighting, as well as electricity production. Moreover, with the new stringent regulations issued by various European countries, following the Energy Performance of Buildings Directive (EPBD, 2010/31/EC, the building envelope, including the glazing elements, needs to have high thermal performance to guarantee Nearly Zero Energy Building (NZEB behavior. This work presents an assessment of energy saving potential of 4 different types of STPV with respect to conventional double pane glass. Dye sensitized solar modules (DSM and thin film modules were considered in the study. Simulations based on an IEA reference office building (STD and on reference buildings prescribed by the new Italian building energy performance regulation (NZEB were carried out. All the glazing peculiarities could be simulated using only one simulation tool, namely IDA ICE 4.7.1. Dye sensitized solar modules resulted as the best performing devices for all orientations and climate zones. The work also evidenced how the requirements of NZEB seem to be too stringent for insulation properties, especially for the climate zone of Rome.

Energy Dependent Divisible Load Theory for Wireless Sensor Network Workload Allocation

Directory of Open Access Journals (Sweden)

Haiyan Shi

2012-01-01

Full Text Available The wireless sensor network (WSN, consisting of a large number of microsensors with wireless communication abilities, has become an indispensable tool for use in monitoring and surveillance applications. Despite its advantages in deployment flexibility and fault tolerance, the WSN is vulnerable to failures due to the depletion of limited onboard battery energy. A major portion of energy consumption is caused by the transmission of sensed results to the master processor. The amount of energy used, in fact, is related to both the duration of sensing and data transmission. Hence, in order to extend the operation lifespan of the WSN, a proper allocation of sensing workload among the sensors is necessary. An assignment scheme is here formulated on the basis of the divisible load theory, namely, the energy dependent divisible load theory (EDDLT for sensing workload allocations. In particular, the amount of residual energies onboard sensors are considered while deciding the workload assigned to each sensor. Sensors with smaller amount of residual energy are assigned lighter workloads, thus, allowing for a reduced energy consumption and the sensor lifespan is extended. Simulation studies are conducted and results have illustrated the effectiveness of the proposed workload allocation method.

Load-following performance and assessment of CANDU fuel

Energy Technology Data Exchange (ETDEWEB)

Tayal, M.; Floyd, M.; Rattan, D.; Xu, Z.; Manzer, A.; Lau, J. [Atomic Energy of Canada Limited, Mississauga, Ontario (Canada); Kohn, E. [Ontario Power Generation, Fuel and Fuel Channel Analysis Dept., Toronto, Ontario (Canada)

1999-09-01

Load following of nuclear reactors is now becoming an economic necessity in some countries. When nuclear power stations are operated in a load-following mode, the reactor and the fuel may be subjected to step changes in power on a weekly, daily, or even hourly basis, depending on the grid's needs. This paper updates the previous surveys of load-following capability of CANDU fuel, focusing mainly on the successful experience at the Bruce B station. As well, initial analytical assessments are provided that illustrate the capability of CANDU fuel to survive conditions other than those for which direct in-reactor evidence is available. (author)

Development of an Energy-Savings Calculation Methodology for Residential Miscellaneous Electric Loads: Preprint

Energy Technology Data Exchange (ETDEWEB)

Hendron, R.; Eastment, M.

2006-08-01

In order to meet whole-house energy savings targets beyond 50% in residential buildings, it will be essential that new technologies and systems approaches be developed to address miscellaneous electric loads (MELs). These MELs are comprised of the small and diverse collection of energy-consuming devices found in homes, including what are commonly known as plug loads (televisions, stereos, microwaves), along with all hard-wired loads that do not fit into other major end-use categories (doorbells, security systems, garage door openers). MELs present special challenges because their purchase and operation are largely under the control of the occupants. If no steps are taken to address MELs, they can constitute 40-50% of the remaining source energy use in homes that achieve 60-70% whole-house energy savings, and this percentage is likely to increase in the future as home electronics become even more sophisticated and their use becomes more widespread. Building America (BA), a U.S. Department of Energy research program that targets 50% energy savings by 2015 and 90% savings by 2025, has begun to identify and develop advanced solutions that can reduce MELs.

Real - time Optimization of Distributed Energy Storage System Operation Strategy Based on Peak Load Shifting

Science.gov (United States)

Wang, Qian; Lu, Guangqi; Li, Xiaoyu; Zhang, Yichi; Yun, Zejian; Bian, Di

2018-01-01

To take advantage of the energy storage system (ESS) sufficiently, the factors that the service life of the distributed energy storage system (DESS) and the load should be considered when establishing optimization model. To reduce the complexity of the load shifting of DESS in the solution procedure, the loss coefficient and the equal capacity ratio distribution principle were adopted in this paper. Firstly, the model was established considering the constraint conditions of the cycles, depth, power of the charge-discharge of the ESS, the typical daily load curves, as well. Then, dynamic programming method was used to real-time solve the model in which the difference of power Δs, the real-time revised energy storage capacity Sk and the permission error of depth of charge-discharge were introduced to optimize the solution process. The simulation results show that the optimized results was achieved when the load shifting in the load variance was not considered which means the charge-discharge of the energy storage system was not executed. In the meantime, the service life of the ESS would increase.

Investigation on energy storage and quick load change control of subcritical circulating fluidized bed boiler units

International Nuclear Information System (INIS)

Gao, Mingming; Hong, Feng; Liu, Jizhen

2017-01-01

Highlights: • The model of energy storage of subcritical CFB boilers is established. • The capacity and increment rate of heat storage are quantified. • A novel load control strategy is proposed to improve the quick load change ability. • An application on the 300 MW CFB unit proves the load change rate to 5–8 MW/min. - Abstract: The energy storage of circulating fluidized bed (CFB) boilers on fuel side cannot be ignored due to the special combustion type different from pulverized coal boilers. The sizable energy storage makes it possible for CFB units to enhance the quick load change ability and to increase the scale of new energy power connected into grid. Through mechanism analysis, the model of energy storage of subcritical CFB boilers has been established for the first time. Then by the project practice, the quantitative analysis is demonstrated for the capacity and control characteristics of energy storage on fuel side and steam water side. Based on the control characteristics and the transformation of the energy storage, a coordinated control system (CCS) control strategy named advanced energy balance (AEB) is designed to shorten the response time through the use of energy storage and to accelerate the load change speed of subcritical CFB units. Finally, a case study on a 300 MW CFB unit proves the feasibility of the proposed control strategy.

Energy and environmental assessment

DEFF Research Database (Denmark)

Lund, Henrik; Sukkumnoed, Decharut

2004-01-01

The paper introduce and discuss strategic environmental assessment (SEA) and economic assessment for energy innovation and suggests approach to influence support for sustainable energy development in Thailand.......The paper introduce and discuss strategic environmental assessment (SEA) and economic assessment for energy innovation and suggests approach to influence support for sustainable energy development in Thailand....

Load management as a smart grid concept for sizing and designing of hybrid renewable energy systems

Science.gov (United States)

Eltamaly, Ali M.; Mohamed, Mohamed A.; Al-Saud, M. S.; Alolah, Abdulrahman I.

2017-10-01

Optimal sizing of hybrid renewable energy systems (HRES) to satisfy load requirements with the highest reliability and lowest cost is a crucial step in building HRESs to supply electricity to remote areas. Applying smart grid concepts such as load management can reduce the size of HRES components and reduce the cost of generated energy considerably. In this article, sizing of HRES is carried out by dividing the load into high- and low-priority parts. The proposed system is formed by a photovoltaic array, wind turbines, batteries, fuel cells and a diesel generator as a back-up energy source. A smart particle swarm optimization (PSO) algorithm using MATLAB is introduced to determine the optimal size of the HRES. The simulation was carried out with and without division of the load to compare these concepts. HOMER software was also used to simulate the proposed system without dividing the loads to verify the results obtained from the proposed PSO algorithm. The results show that the percentage of division of the load is inversely proportional to the cost of the generated energy.

Application of X-ray methods to assess grain vulnerability to damage resulting from multiple loads

International Nuclear Information System (INIS)

Zlobecki, A.

1995-01-01

The aim of the work is to describe wheat grain behavior under multiple dynamic loads with various multipliers. The experiments were conducted on Almari variety grain. Grain moisture was 11, 16, 21 and 28%. A special ram stand was used for loading the grain. The experiments were carried out using an 8 g weight, equivalent to impact energy of 4,6 x 10 -3 [J]. The X-ray method was used to assess damage. The exposure time was 8 minutes with X-ray lamp voltage equal to 15 kV. The position index was used as the measure of the damage. The investigation results were elaborated statistically. Based on the results of analysis of variance, regression analysis, the d-Duncan test and the Kolmogorov-Smirnov test, the damage number was shown to depend greatly on the number of impacts for the whole range of moisture of the grain loaded. (author)

Energy management of a university campus utilizing short-term load forecasting with an artificial neural network

Science.gov (United States)

Palchak, David

Electrical load forecasting is a tool that has been utilized by distribution designers and operators as a means for resource planning and generation dispatch. The techniques employed in these predictions are proving useful in the growing market of consumer, or end-user, participation in electrical energy consumption. These predictions are based on exogenous variables, such as weather, and time variables, such as day of week and time of day as well as prior energy consumption patterns. The participation of the end-user is a cornerstone of the Smart Grid initiative presented in the Energy Independence and Security Act of 2007, and is being made possible by the emergence of enabling technologies such as advanced metering infrastructure. The optimal application of the data provided by an advanced metering infrastructure is the primary motivation for the work done in this thesis. The methodology for using this data in an energy management scheme that utilizes a short-term load forecast is presented. The objective of this research is to quantify opportunities for a range of energy management and operation cost savings of a university campus through the use of a forecasted daily electrical load profile. The proposed algorithm for short-term load forecasting is optimized for Colorado State University's main campus, and utilizes an artificial neural network that accepts weather and time variables as inputs. The performance of the predicted daily electrical load is evaluated using a number of error measurements that seek to quantify the best application of the forecast. The energy management presented utilizes historical electrical load data from the local service provider to optimize the time of day that electrical loads are being managed. Finally, the utilization of forecasts in the presented energy management scenario is evaluated based on cost and energy savings.

Energy management for vehicle power net with flexible electric load demand

NARCIS (Netherlands)

Kessels, J.T.B.A.; Bosch, van den P.P.J.; Koot, M.W.T.; Jager, de A.G.

2005-01-01

The electric power demand in road vehicles increases rapidly and to supply all electric loads efficiently, energy management (EM) turns out to be a necessity. In general, EM exploits the storage capacity of a buffer connected to the vehicle's power net, such that energy is stored or retrieved at

Survey of energy load leveling system in Europe; Energy fuka heijunka taisaku ni kansuru Europe chosa

Energy Technology Data Exchange (ETDEWEB)

Suzuki, Y. [Setsunan University, Osaka (Japan). Faculty of Engineering

1998-05-05

This paper describes the survey of energy load leveling systems in Europe. In Denmark, especially regional heating is remarkably diffused, and they have 350 plants. With extending the service areas, the energy load leveling has been promoted. For the cogeneration plants of SK Power, the largest electric power company, they have hot water heat storage tanks for regional heat supply with a total capacity 2,200 MWh. The regional heating system in Goeteborg City of Sweden supplies 80% of the total heat demand of the city. Unused energy sources derived from petroleum refining, sewage treatment, and garbage burning are utilized. In Uppsala, they have seasonal heat storage systems using solar heat. The Vienna Regional Heat Supply Corporation supplies heat equivalent to 5,000 GWh a year. Cogeneration plants and garbage burning plants are used as heat sources, and 25% of the total heating in the city is supplied. In Austria, they have an electric power demand with a peak in winter, and they have a pumped-storage power station in Kaprun for the annual load leveling using dump power in summer. This paper also introduces a compressed air storage gas turbine plant at Huntorf of Germany, and a large-scale underground natural gas storage of Gaz de France. 6 figs.

Analysis and Assessment of Environmental Load of Vending Machines by a LCA Method, and Eco-Improvement Effect

Science.gov (United States)

Kimura, Yukio; Sadamichi, Yucho; Maruyama, Naoki; Kato, Seizo

These days the environmental impact due to vending machines'(VM) diffusion has greatly been discussed. This paper describes the numerical evaluation of the environmental impact by using the LCA (Life Cycle Assessment) scheme and then proposes eco-improvements' strategy toward environmentally conscious products(ECP). A new objective and universal consolidated method for the LCA-evaluation, so-called LCA-NETS(Numerical Eco-load Standardization ) developed by the authors is applied to the present issue. As a result, the environmental loads at the 5years' operation and the material procurement stages are found to dominate others over the life cycle. Further eco-improvement is realized by following the order of the LCA-NETS magnitude; namely, energy saving, materials reducing, parts' re-using, and replacing with low environmental load material. Above all, parts' re-using is specially recommendable for significant reduction of the environmental loads toward ECP.

Global and local emission impact assessment of distributed cogeneration systems with partial-load models

International Nuclear Information System (INIS)

Mancarella, Pierluigi; Chicco, Gianfranco

2009-01-01

Small-scale distributed cogeneration technologies represent a key resource to increase generation efficiency and reduce greenhouse gas emissions with respect to conventional separate production means. However, the diffusion of distributed cogeneration within urban areas, where air quality standards are quite stringent, brings about environmental concerns on a local level. In addition, partial-load emission worsening is often overlooked, which could lead to biased evaluations of the energy system environmental performance. In this paper, a comprehensive emission assessment framework suitable for addressing distributed cogeneration systems is formulated. Local and global emission impact models are presented to identify upper and lower boundary values of the environmental pressure from pollutants that would be emitted from reference technologies, to be compared to the actual emissions from distributed cogeneration. This provides synthetic information on the relative environmental impact from small-scale CHP sources, useful for general indicative and non-site-specific studies. The emission models are formulated according to an electrical output-based emission factor approach, through which off-design operation and relevant performance are easily accounted for. In particular, in order to address the issues that could arise under off-design operation, an equivalent load model is incorporated within the proposed framework, by exploiting the duration curve of the cogenerator loading and the emissions associated to each loading level. In this way, it is possible to quantify the contribution to the emissions from cogeneration systems that might operate at partial loads for a significant portion of their operation time, as for instance in load-tracking applications. Suitability of the proposed methodology is discussed with respect to hazardous air pollutants such as NO x and CO, as well as to greenhouse gases such as CO 2 . Two case study applications based on the emission

Superconducting magnetic energy storage for electric utility load leveling: A study of cost vs. stored energy

International Nuclear Information System (INIS)

Luongo, C.A.; Loyd, R.J.

1987-01-01

Superconducting Magnetic Energy Storage (SMES) is a promising technology for electric utility load leveling. This paper presents the results of a study to establish the capital cost of SMES as a function of stored energy. Energy-related coil cost and total installed plant cost are given for construction in nominal soil and in competent rock. Economic comparisons are made between SMES and other storage technologies and peaking gas turbines. SMES is projected to be competitive at stored energies as low as 1000 MWh

Water Quality Assessment and Total Maximum Daily Loads Information (ATTAINS)

Data.gov (United States)

U.S. Environmental Protection Agency — The Water Quality Assessment TMDL Tracking And Implementation System (ATTAINS) stores and tracks state water quality assessment decisions, Total Maximum Daily Loads...

Economic assessment of electric energy storage for load shifting in positive energy building

DEFF Research Database (Denmark)

Dumont, Olivier; Do Carmo, Carolina Madeira Ramos; Georges, Emeline

2017-01-01

Net zero energy buildings and positive energy buildings are gaining more and more interest. This paper evaluates the impact of the integration of a battery in a positive energy building used to increase its self-consumption of electricity. Parametric studies are carried out by varying the buildin...... and a 3.7 kWh battery. Finally, simple correlations (based on the feed-in tariff, the annual electrical consumption and production) to predict the optimal size of battery and the lowest payback period are proposed.......Net zero energy buildings and positive energy buildings are gaining more and more interest. This paper evaluates the impact of the integration of a battery in a positive energy building used to increase its self-consumption of electricity. Parametric studies are carried out by varying the building...... envelope characteristics, the power supply system, the climate, the lighting and appliances profiles, the roof tilt angle, the battery size and the electricity tariffs, leading to 3200 cases. The analysis is performed on an annual basis in terms of self-consumption and self-production rate and payback...

Peak load arrangements : Assessment of Nordel guidelines

Energy Technology Data Exchange (ETDEWEB)

2009-07-01

Two Nordic countries, Sweden and Finland, have legislation that empowers the TSO to acquire designated peak load resources to mitigate the risk for shortage situations during the winter. In Denmark, the system operator procures resources to maintain a satisfactory level of security of supply. In Norway the TSO has set up a Regulation Power Option Market (RKOM) to secure a satisfactory level of operational reserves at all times, also in winter with high load demand. Only the arrangements in Finland and Sweden fall under the heading of Peak Load Arrangements defined in Nordel Guidelines. NordREG has been invited by the Electricity Market Group (EMG) to evaluate Nordel's proposal for 'Guidelines for transitional Peak Load Arrangements'. The EMG has also financed a study made by EC Group to support NordREG in the evaluation of the proposal. The study has been taken into account in NordREG's evaluation. In parallel to the EMG task, the Swedish regulator, the Energy Markets Inspectorate, has been given the task by the Swedish government to investigate a long term solution of the peak load issue. The Swedish and Finnish TSOs have together with Nord Pool Spot worked on finding a harmonized solution for activation of the peak load reserves in the market. An agreement accepted by the relevant authorities was reached in early January 2009, and the arrangement has been implemented since 19th January 2009. NordREG views that the proposed Nordel guidelines have served as a starting point for the presently agreed procedure. However, NordREG does not see any need to further develop the Nordel guidelines for peak load arrangements. NordREG agrees with Nordel that the market should be designed to solve peak load problems through proper incentives to market players. NordREG presumes that the relevant authorities in each country will take decisions on the need for any peak load arrangement to ensure security of supply. NordREG proposes that such decisions should be

Behavioral and fMRI evidence of the differing cognitive load of domain-specific assessments.

Science.gov (United States)

Howard, S J; Burianová, H; Ehrich, J; Kervin, L; Calleia, A; Barkus, E; Carmody, J; Humphry, S

2015-06-25

Standards-referenced educational reform has increased the prevalence of standardized testing; however, whether these tests accurately measure students' competencies has been questioned. This may be due to domain-specific assessments placing a differing domain-general cognitive load on test-takers. To investigate this possibility, functional magnetic resonance imaging (fMRI) was used to identify and quantify the neural correlates of performance on current, international standardized methods of spelling assessment. Out-of-scanner testing was used to further examine differences in assessment results. Results provide converging evidence that: (a) the spelling assessments differed in the cognitive load placed on test-takers; (b) performance decreased with increasing cognitive load of the assessment; and (c) brain regions associated with working memory were more highly activated during performance of assessments that were higher in cognitive load. These findings suggest that assessment design should optimize the cognitive load placed on test-takers, to ensure students' results are an accurate reflection of their true levels of competency. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Damage assessment in CFRP laminates exposed to impact fatigue loading

International Nuclear Information System (INIS)

Tsigkourakos, George; Silberschmidt, Vadim V; Ashcroft, I A

2011-01-01

Demand for advanced engineering composites in the aerospace industry is increasing continuously. Lately, carbon fibre reinforced polymers (CFRPs) became one of the most important structural materials in the industry due to a combination of characteristics such as: excellent stiffness, high strength-to-weight ratio, and ease of manufacture according to application. In service, aerospace composite components and structures are exposed to various transient loads, some of which can propagate in them as cyclic impacts. A typical example is an effect of the wind gusts during flight. This type of loading is known as impact fatigue (IF); it is a repetition of low-energy impacts. Such loads can cause various types of damage in composites: fibre breaking, transverse matrix cracking, de-bonding between fibres and matrix and delamination resulting in reduction of residual stiffness and loss of functionality. Furthermore, this damage is often sub-surface, which reinforces the need for more regular inspection. The effects of IF are of major importance due its detrimental effect on the structural integrity of components that can be generated after relatively few impacts at low force levels compared to those in a standard fatigue regime. This study utilises an innovative testing system with the capability of subjecting specimens to a series of repetitive impacts. The primary subject of this paper is to assess the damaging effect of IF on the behaviour of drilled CFRP specimens, exposed to such loading. A detailed damage analysis is implemented utilising an X-ray micro computed tomography system. The main findings suggested that at early stages of life damage is governed by o degree splits along the length of the specimens resulting in a 20% reduction of stiffness. The final failure damage scenario indicated that transverse crasks in the 90 degree plies are the main reason for complete delamination which can be translated to a 50% stiffness reduction.

Energy absorption capabilities of composite sandwich panels under blast loads

Science.gov (United States)

Sankar Ray, Tirtha

As blast threats on military and civilian structures continue to be a significant concern, there remains a need for improved design strategies to increase blast resistance capabilities. The approach to blast resistance proposed here is focused on dissipating the high levels of pressure induced during a blast through maximizing the potential for energy absorption of composite sandwich panels, which are a competitive structural member type due to the inherent energy absorption capabilities of fiber reinforced polymer (FRP) composites. Furthermore, the middle core in the sandwich panels can be designed as a sacrificial layer allowing for a significant amount of deformation or progressive failure to maximize the potential for energy absorption. The research here is aimed at the optimization of composite sandwich panels for blast mitigation via energy absorption mechanisms. The energy absorption mechanisms considered include absorbed strain energy due to inelastic deformation as well as energy dissipation through progressive failure of the core of the sandwich panels. The methods employed in the research consist of a combination of experimentally-validated finite element analysis (FEA) and the derivation and use of a simplified analytical model. The key components of the scope of work then includes: establishment of quantified energy absorption criteria, validation of the selected FE modeling techniques, development of the simplified analytical model, investigation of influential core architectures and geometric parameters, and investigation of influential material properties. For the parameters that are identified as being most-influential, recommended values for these parameters are suggested in conceptual terms that are conducive to designing composite sandwich panels for various blast threats. Based on reviewing the energy response characteristic of the panel under blast loading, a non-dimensional parameter AET/ ET (absorbed energy, AET, normalized by total energy

Reserves in load capacity assessment of existing bridges

Science.gov (United States)

Žitný, Jan; Ryjáček, Pavel

2017-09-01

High percentage of all railway bridges in the Czech Republic is made of structural steel. Majority of these bridges is designed according to historical codes and according to the deterioration, they have to be assessed if they satisfy the needs of modern railway traffic. The load capacity assessment of existing bridges according to Eurocodes is however often too conservative and especially, braking and acceleration forces cause huge problems to structural elements of the bridge superstructure. The aim of this paper is to review the different approaches for the determination of braking and acceleration forces. Both, current and historical theoretical models and in-situ measurements are considered. The research of several local European state norms superior to Eurocode for assessment of existing railway bridges shows the big diversity of used local approaches and the conservativeness of Eurocode. This paper should also work as an overview for designers dealing with load capacity assessment, revealing the reserves for existing bridges. Based on these different approaches, theoretical models and data obtained from the measurements, the method for determination of braking and acceleration forces on the basis of real traffic data should be proposed.

Load Matching and Grid Interaction of Net Zero Energy Buildings

DEFF Research Database (Denmark)

Voss, Karsten; Candanedo, José A.; Geier, Sonja

2010-01-01

of seasonal energy storage on-site. Even though the wording “Net Zero Energy Building” focuses on the annual energy balance, large differences may occur between solution sets in the amount of grid interaction needed to reach the goal. The paper reports on the analysis of example buildings concerning the load......“Net Zero Energy Building” has become a prominent wording to describe the synergy of energy efficient building and renewable energy utilization to reach a balanced energy budget over a yearly cycle. Taking into account the energy exchange with a grid infrastructure overcomes the limitations...... matching and grid interaction. Indices to describe both issues are proposed and foreseen as part of a harmonized definition framework. The work is part of subtask A of the IEA SHCP Task40/ECBCS Annex 52: “Towards Net Zero Energy Solar Buildings”....

Mobility-Aware and Load Balancing Based Clustering Algorithm for Energy Conservation in MANET

Institute of Scientific and Technical Information of China (English)

XU Li; ZHENG Bao-yu; GUO Gong-de

2005-01-01

Mobile ad hoc network (MANET) is one of wireless communication network architecture that has received a lot of attention. MANET is characterized by dynamic network topology and limited energy. With mobility-aware and load balancing based clustering algorithm (MLCA), this paper proposes a new topology management strategy to conserve energy. Performance simulation results show that the proposed MLCA strategy can balances the traffic load inside the whole network, so as to prolong the network lifetime, meanly, at the same time, achieve higher throughput ratio and network stability.

An Energy Saving Green Plug Device for Nonlinear Loads

Science.gov (United States)

Bloul, Albe; Sharaf, Adel; El-Hawary, Mohamed

2018-03-01

The paper presents a low cost a FACTS Based flexible fuzzy logic based modulated/switched tuned arm filter and Green Plug compensation (SFC-GP) scheme for single-phase nonlinear loads ensuring both voltage stabilization and efficient energy utilization. The new Green Plug-Switched filter compensator SFC modulated LC-Filter PWM Switched Capacitive Compensation Devices is controlled using a fuzzy logic regulator to enhance power quality, improve power factor at the source and reduce switching transients and inrush current conditions as well harmonic contents in source current. The FACTS based SFC-GP Device is a member of family of Green Plug/Filters/Compensation Schemes used for efficient energy utilization, power quality enhancement and voltage/inrush current/soft starting control using a dynamic error driven fuzzy logic controller (FLC). The device with fuzzy logic controller is validated using the Matlab / Simulink Software Environment for enhanced power quality (PQ), improved power factor and reduced inrush currents. This is achieved using modulated PWM Switching of the Filter-Capacitive compensation scheme to cope with dynamic type nonlinear and inrush cyclical loads..

Linear active disturbance rejection-based load frequency control concerning high penetration of wind energy

International Nuclear Information System (INIS)

Tang, Yanmei; Bai, Yan; Huang, Congzhi; Du, Bin

2015-01-01

Highlights: • A disturbance rejection solution to the load frequency control issue is proposed. • Several power systems with wind energy conversation system have been tested. • A tuning algorithm of the controller parameters was proposed. • The performance of the proposed approach is better than traditional controllers. - Abstract: A new grid load frequency control approach is proposed for the doubly fed induction generator based wind power plants. The load frequency control issue in a power system is undergoing fundamental changes due to the rapidly growing amount of wind energy conversation system, and concentrating on maintaining generation-load balance and disturbance rejection. The prominent feature of the linear active disturbance rejection control approach is that the total disturbance can be estimated and then eliminated in real time. And thus, it is a feasible solution to deal with the load frequency control issue. In this paper, the application of the linear active disturbance rejection control approach in the load frequency control issue for a complex power system with wind energy conversation system based on doubly fed induction generator is investigated. The load frequency control issue is formulated as a decentralized multi-objective optimization control problem, the solution to which is solved by the hybrid particle swarm optimization technique. To show the effectiveness of the proposed control scheme, the robust performance testing based on Monte-Carlo approach is carried out. The performance superiority of the system with the proposed linear active disturbance rejection control approach over that with the traditional proportional integral and fuzzy-proportional integral-based controllers is validated by the simulation results

Public policy analysis of energy efficiency and load management in changing electricity businesses

International Nuclear Information System (INIS)

Vine, Edward; Hamrin, Jan; Eyre, Nick; Crossley, David; Maloney, Michelle; Watt, Greg

2003-01-01

The focus of this paper is (1) the potential effectiveness of the reform of the electricity industry on promoting energy efficiency and load management, and (2) the potential effectiveness of new mechanisms for promoting energy efficiency and load management. Many countries are initiating reforms of their power sectors to stimulate private investment, increase operation and management efficiencies, and lower the cost of power. These countries are unbundling vertically integrated utilities into distinct generation, transmission, distribution and retail supply companies; introducing commercial management principles to government-owned monopolies; and in many cases transferring operation or ownership to private companies. Electric industry restructuring may force regulators and policy makers to re-examine existing mechanisms for promoting load management and energy efficiency. In some cases, electric industry restructuring replaces the long-standing relationship between a single monopoly provider and protected customer franchise with a new set of relationships among retail electricity suppliers and customers who may now be free to choose suppliers. In these types of situations, markets, not government regulators and utility monopolies, are seen as determining future energy production and consumption decisions. However, it is uncertain whether this type of restructuring will overcome important market barriers to energy efficiency that limit markets for energy-efficient products and services from functioning effectively. As a result of these barriers, a large, untapped potential for cost-effective energy-efficiency investments exists. Supporters of public policies argue that energy-efficiency programs are an appropriate government strategy to capture economic efficiencies that the market cannot secure unassisted

Public policy analysis of energy efficiency and load management in changing electricity business

Energy Technology Data Exchange (ETDEWEB)

Vine, E. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States). Energy Analysis Dept.; Hamrin, J. [Centre for Resource Solutions (United States); Eyre, N. [Energy Savings Trust (United Kingdom); Crossley, D.; Maloney, M.; Watt, G. [Energy Futures Australia Pty Ltd (Australia)

2003-04-01

The focus of this paper is (1) the potential effectiveness of the reform of the electricity industry on promoting energy efficiency and load management, and (2) the potential effectiveness of new mechanisms for promoting energy efficiency and load management. Many countries are initiating reforms of their power sectors to stimulate private investment, increase operation and management efficiencies, and lower the cost of power. These countries are unbundling vertically integrated utilities into distinct generation, transmission, distribution and retail supply companies; introducing commercial management principles to government-owned monopolies; and in many cases transferring operation or ownership to private companies. Electric industry restructuring may force regulators and policy makers to re-examine existing mechanisms for promoting load management and energy efficiency. In some cases, electric industry restructuring replaces the long-standing relationship between a single monopoly provider and protected customer franchise with a new set of relationships among retail electricity suppliers and customers who may now be free to choose suppliers. In these types of situations, markets, not government regulators and utility monopolies, are seen as determining future energy production and consumption decisions. However, it is uncertain whether this type of restructuring will overcome important market barriers to energy efficiency that limit markets for energy-efficient products and services from functioning effectively. As a result of these barriers, a large, untapped potential for cost-effective energy-efficiency investments exists. Supporters of public policies argue that energy-efficiency programs are an appropriate government strategy to capture economic efficiencies that the market cannot secure unassisted. (author)

Public policy analysis of energy efficiency and load management in changing electricity businesses

Energy Technology Data Exchange (ETDEWEB)

Vine, Edward; Hamrin, Jan; Eyre, Nick; Crossley, David; Maloney, Michelle; Watt, Greg

2003-04-01

The focus of this paper is (1) the potential effectiveness of the reform of the electricity industry on promoting energy efficiency and load management, and (2) the potential effectiveness of new mechanisms for promoting energy efficiency and load management. Many countries are initiating reforms of their power sectors to stimulate private investment, increase operation and management efficiencies, and lower the cost of power. These countries are unbundling vertically integrated utilities into distinct generation, transmission, distribution and retail supply companies; introducing commercial management principles to government-owned monopolies; and in many cases transferring operation or ownership to private companies. Electric industry restructuring may force regulators and policy makers to re-examine existing mechanisms for promoting load management and energy efficiency. In some cases, electric industry restructuring replaces the long-standing relationship between a single monopoly provider and protected customer franchise with a new set of relationships among retail electricity suppliers and customers who may now be free to choose suppliers. In these types of situations, markets, not government regulators and utility monopolies, are seen as determining future energy production and consumption decisions. However, it is uncertain whether this type of restructuring will overcome important market barriers to energy efficiency that limit markets for energy-efficient products and services from functioning effectively. As a result of these barriers, a large, untapped potential for cost-effective energy-efficiency investments exists. Supporters of public policies argue that energy-efficiency programs are an appropriate government strategy to capture economic efficiencies that the market cannot secure unassisted.

Specific Energy of Hard Coal Under Load

Directory of Open Access Journals (Sweden)

Bogusz Anna

2015-03-01

Full Text Available The article presents results of experimental tests of energy parameters of hard coals under loading, collected from research sites located within five main geologic structures of Upper Silesian Coal Basin (GZW - Main Trough, Main Anticline, Bytom Trough, Rybnik Trough and Chwałowice Trough. Coals from12 mines were analysed, starting with seams of group 200, through groups 400, 500, 600 and, finally, seams of group 700. Coal of each of the groups of seams underwent uniaxial compression stress of the energy parameters, in a servo-controlled testing machine MTS-810NEW, for the full range of strain of the tested coal samples. Based on the tests the dependence of different types of specific energy of longitudinal strain of coals on the value of uniaxial compression strength was determined. The dependence of the value of dissipated energy and kinetic energy of coals on the uniaxial compression strength was described with a linear function, both for coals which due to their age belong to various bed sand for various lithotypes of coal. An increase in the value of dissipated energy and in kinetic energy was observed, which was correlated with an increase in uniaxial compression strength of coal. The share of dissipated energy is dominant in the total energy of strain. Share of recoverable energy in the total energy of strain is small, independent of the compression strength of coals and is at most a few per cent high. In coals of low strength and dominant share of dissipated energy, share of recoverable energy is the biggest among the tested coals. It was shown that following an increase in compression strength the share of recoverable energy decreases, while the share of dissipated energy in the total energy increases. Further studies of specific energy of longitudinal strain of rocks in the full-range strain will be the next step inperfecting methodology of research into natural rock burst susceptibility of Carboniferous rock mass and changes in the

Green IGP Link Weights for Energy-efficiency and Load-balancing in IP Backbone Networks

OpenAIRE

Francois, Frederic; Wang, Ning; Moessner, Klaus; Georgoulas, Stylianos; Xu, Ke

2013-01-01

The energy consumption of backbone networks has become a primary concern for network operators and regulators due to the pervasive deployment of wired backbone networks to meet the requirements of bandwidth-hungry applications. While traditional optimization of IGP link weights has been used in IP based load-balancing operations, in this paper we introduce a novel link weight setting algorithm, the Green Load-balancing Algorithm (GLA), which is able to jointly optimize both energy efficiency ...

Life cycle assessment of woody biomass energy utilization: Case study in Gifu Prefecture, Japan

International Nuclear Information System (INIS)

Tabata, Tomohiro; Okuda, Takaaki

2012-01-01

This paper discusses the effectiveness of a woody biomass utilization system that would result in increased net energy production through wood pellet production, along with energy recovery processes as they relate to household energy demand. The direct environmental load of the system, including wood pellet production and utilization processes, was evaluated. Furthermore, the indirect load, including the economic impact of converting the existing fossil-fuel-based energy system into a woody biomass-based system, on the entire society was also evaluated. Gifu Prefecture in Japan was selected for a case study, which included a comparative evaluation of the environmental load and costs both with and without coordination with the wood pellet production process and the waste-to-energy of municipal solid waste process, using the life cycle assessment methodology. If the release of greenhouse gases from the combustion of wood pellets is included in calculations, then burning wood pellets results in unfavorable environmental consequences. However, when the reduced indirect environmental load due to the utilization of wood pellets versus petroleum is included in calculations, then favorable environmental consequences result, with a net reduction of greenhouse gases emissions by 14,060 ton-CO 2eq . -- Highlights: ► We evaluate economic and environmental impact of woody biomass utilization in household. ► Wood pellet utilization for house heating is advantageous to reduce greenhouse gas emissions. ► Reduction effect of greenhouse gas will be canceled out if carbon neutrality were considered. ► Net greenhouse gas emissions considering conversion of an ordinal energy system will be minus. ► Wood pellet utilization is advantageous not only in global warming but also for resource conservation.

Office Buildings: Assessing and Reducing Plug and Process Loads in Office Buildings (Fact Sheet)

Energy Technology Data Exchange (ETDEWEB)

2013-04-01

Plug and process loads (PPLs) in commercial buildings account for almost 5% of U.S. primary energy consumption. Minimizing these loads is a primary challenge in the design and operation of an energy-efficient building. PPLs are not related to general lighting, heating, ventilation, cooling, and water heating, and typically do not provide comfort to the occupants. They use an increasingly large fraction of the building energy use pie because the number and variety of electrical devices have increased along with building system efficiency. Reducing PPLs is difficult because energy efficiency opportunities and the equipment needed to address PPL energy use in office spaces are poorly understood.

Retail Buildings: Assessing and Reducing Plug and Process Loads in Retail Buildings (Fact Sheet)

Energy Technology Data Exchange (ETDEWEB)

2013-04-01

Plug and process loads (PPLs) in commercial buildings account for almost 5% of U.S. primary energy consumption. Minimizing these loads is a primary challenge in the design and operation of an energy-efficient building. PPLs are not related to general lighting, heating, ventilation, cooling, and water heating, and typically do not provide comfort to the occupants. They use an increasingly large fraction of the building energy use pie because the number and variety of electrical devices have increased along with building system efficiency. Reducing PPLs is difficult because energy efficiency opportunities and the equipment needed to address PPL energy use in retail spaces are poorly understood.

An assessment of energy options for a remote first nation community. Paper no. IGEC-1-055

International Nuclear Information System (INIS)

Ianniciello, C.; Wild, P.; Pitt, L.; Artz, S.

2005-01-01

Development of renewable energy systems for remote communities is gaining interest among government, utilities, NGOs and the communities themselves as a means of improving lifestyles of community members and showcasing renewable energy systems. The Huu-ay-aht First Nation, whose traditional territory is located on the west side of Vancouver Island in British Columbia, is a community which has energy related problems and energy related opportunities. The objective of this study is to assess possible energy options for the Huu-ay-aht First Nation traditional territory. Current and future energy services within the territory were used as the starting point for developing energy system options. Extensive consultation with community members was instrumental in clearly defining the objectives of the study and understanding the territory's energy demand. The energy demand assessment included an estimation of the electric, heating and transportation loads in the community, an assessment of efficiency and demand side management (DSM) options, and an estimation of potential future demand scenarios. Energy resources were assessed, with viable ones retained for consideration in potential energy system options. The information from the community consultations, demand estimates and resource assessments are being used in the development and analysis of energy system options to support the Huu-ay-aht's energy needs and community goals. (author)

Plug-Load Control and Behavioral Change Research in GSA Office Buildings

Energy Technology Data Exchange (ETDEWEB)

Metzger, I.; Cutler, D.; Sheppy, M.

2012-10-01

The U.S. General Services Administration (GSA) owns and leases over 354 million square feet (ft2) of space in over 9,600 buildings [1]. GSA is a leader among federal agencies in aggressively pursuing energy efficiency (EE) opportunities for its facilities and installing renewable energy (RE) systems to provide heating, cooling, and power to these facilities. According to several energy assessments of GSA's buildings conducted by the National Renewable Energy Laboratory (NREL), plug-loads account for approximately 21% of the total electricity consumed within a standard GSA Region 3 office building. This study aims to provide insight on how to effectively manage plug-load energy consumption and attain higher energy and cost savings for plug-loads. As GSA improves the efficiency of its building stock, plug-loads will become an even greater portion of its energy footprint.

Towards smart energy systems: application of kernel machine regression for medium term electricity load forecasting.

Science.gov (United States)

Alamaniotis, Miltiadis; Bargiotas, Dimitrios; Tsoukalas, Lefteri H

2016-01-01

Integration of energy systems with information technologies has facilitated the realization of smart energy systems that utilize information to optimize system operation. To that end, crucial in optimizing energy system operation is the accurate, ahead-of-time forecasting of load demand. In particular, load forecasting allows planning of system expansion, and decision making for enhancing system safety and reliability. In this paper, the application of two types of kernel machines for medium term load forecasting (MTLF) is presented and their performance is recorded based on a set of historical electricity load demand data. The two kernel machine models and more specifically Gaussian process regression (GPR) and relevance vector regression (RVR) are utilized for making predictions over future load demand. Both models, i.e., GPR and RVR, are equipped with a Gaussian kernel and are tested on daily predictions for a 30-day-ahead horizon taken from the New England Area. Furthermore, their performance is compared to the ARMA(2,2) model with respect to mean average percentage error and squared correlation coefficient. Results demonstrate the superiority of RVR over the other forecasting models in performing MTLF.

Real time security assessment in national load dispatch centre, Tenaga Nasional Berhad, Malaysia

Energy Technology Data Exchange (ETDEWEB)

Sreedharan, G. [Tenaga Nasional Berhad, Kuala Lumpur (Malaysia); Moghavvemi, M. [Univ. of Malaya, Kuala Lumpur (Malaysia)

2007-07-01

Electric energy is one of the most important resources of modern industrial society. Electric power is available to the user instantly at the correct voltage, frequency and exactly at the amount that is needed. However, the power system is subjected to constant disturbances created by random load changes, faults created by natural causes and by equipment failures. One of the major impacts of the disturbances to the system is the impact imposed on transmission networks or corridors, which have increased the demand for more accurate and up to date information on the power system. It has become impossible to operate the system with an acceptable degree of security by using traditional operational planning studies that are conducted off-line and use forecast conditions to predict system security limits. Therefore the use of on-line security assessment is quickly becoming a necessity. This paper simplified the general off-line security assessment methodology by attempting to use the real time system snap shot data as an input to the dynamic security assessment tool namely VSAT. The study used raw data produced at every 10 minute cycle in order to conduct a security assessment of the power system, including current power system load; network topology; unit commitment; and generator and transmission line outages. The purpose of the project was to implement a real time security assessment to benefit the system operators to assist them in their daily work in monitoring and operating the power system in Tenaga Nasional Berhad. The paper discussed project implementation including a description of the project and project background. It discussed the operation of VSAT, result display, and future enhancement. 18 refs., 5 figs.

Considering supply and demand of electric energy in life cycle assessments - a review of current methodologies

International Nuclear Information System (INIS)

Rehberger, M.; Hiete, M.

2015-01-01

A stable power grid requires a balance between electricity supply and demand. To compensate for changes in the demand the network operator puts on or takes off power plants from the net. Peak load plants operate only at times of high electricity demand. As levels for air pollutants emissions are typically lower for peak load plants for reasons of cost-effectiveness, one could argue that a unit of electric energy consumed during peak load has always been associated with a higher environmental impact than at other times. Furthermore, renewable energy technologies, smart approaches for improving the matching between electricity consumption and supply and new products such as electric vehicles or net zero emission buildings gain in importance. In life cycle assessment (LCA) environmental impacts associated with the production and possibly transmission of electricity are most often assessed based on temporally averaged national electricity mixes as electricity flows cannot be traced back to their origin. Neither fluctuations in the supply structure nor the composition of energy supply at a certain moment or regional differences are accounted for. A literature review of approaches for handling electricity in LCA is carried out to compare strengths and weaknesses of the approaches. A better understanding and knowledge about the source of electricity at a given time and place might be valuable information for further reducing environmental impacts, e.g. by shifting electricity consumption to times with ample supply of renewables. Integrating such information into LCA will allow a fairer assessment of a variety of new products which accept a lower energy efficiency to achieve a better integration of renewables into the grid. (authors)

Energy Optimization Assessment at U.S. Army Installations: Fort Bliss, TX

Science.gov (United States)

2008-09-01

Log dampers, temperatures, actuator signals, and other parameters to identify problems. Adjust chiller and boiler setpoints and control curves...installation. The lowest setpoints were found in the Centennial Club, with 52 °F during unoccupied hours (morn- ing). The chillers ran pretty much fully loaded...ER D C/ CE R L TR -0 8 -1 5 Energy Optimization Assessment at U.S. Army Installations Fort Bliss, TX David M. Underwood, Alexander M

Optimum community energy storage system for demand load shifting

International Nuclear Information System (INIS)

Parra, David; Norman, Stuart A.; Walker, Gavin S.; Gillott, Mark

2016-01-01

Highlights: • PbA-acid and lithium-ion batteries are optimised up to a 100-home community. • A 4-period real-time pricing and Economy 7 (2-period time-of-use) are compared. • Li-ion batteries perform worse with Economy 7 for small communities and vice versa. • The community approach reduced the levelised cost by 56% compared to a single home. • Heat pumps reduced the levelised cost and increased the profitability of batteries. - Abstract: Community energy storage (CES) is becoming an attractive technological option to facilitate the use of distributed renewable energy generation, manage demand loads and decarbonise the residential sector. There is strong interest in understanding the techno-economic benefits of using CES systems, which energy storage technology is more suitable and the optimum CES size. In this study, the performance including equivalent full cycles and round trip efficiency of lead-acid (PbA) and lithium-ion (Li-ion) batteries performing demand load shifting are quantified as a function of the size of the community using simulation-based optimisation. Two different retail tariffs are compared: a time-of-use tariff (Economy 7) and a real-time-pricing tariff including four periods based on the electricity prices on the wholesale market. Additionally, the economic benefits are quantified when projected to two different years: 2020 and a hypothetical zero carbon year. The findings indicate that the optimum PbA capacity was approximately twice the optimum Li-ion capacity in the case of the real-time-pricing tariff and around 1.6 times for Economy 7 for any community size except a single home. The levelised cost followed a negative logarithmic trend while the internal rate of return followed a positive logarithmic trend as a function of the size of the community. PbA technology reduced the levelised cost down to 0.14 £/kW h when projected to the year 2020 for the retail tariff Economy 7. CES systems were sized according to the demand load and

Serviceability design load factors and reliability assessments for reinforced concrete containment structures

International Nuclear Information System (INIS)

Han Bong Koo

1998-01-01

A reinforced concrete nuclear power plant containment structure is subjected to various random static and stochastic loads during its lifetime. Since these loads involve inherent randomness and other uncertainties, an appropriate probabilistic model for each load must be established in order to perform reliability analysis. The current ASME code for reinforced concrete containment structures are not based on probability concepts. The stochastic nature of natural hazard or accidental loads and the variations of material properties require a probabilistic approach for a rational assessment of structural safety and performance. The paper develops probability-based load factors for the limit state design of reinforced concrete containment structures. The purpose of constructing reinforced concrete containment structure is to protect against radioactive release, and so the use of a serviceability limit state against crack failure that can cause the emission of radioactive materials is suggested as a critical limit state for reinforced concrete containment structures. Load factors for the design of reinforced concrete containment structures are proposed and carried out the reliability assessments. (orig.)

Energy Evolution Mechanism and Confining Pressure Effect of Granite under Triaxial Loading-Unloading Cycles

Science.gov (United States)

Wang, Hao; Miao, Sheng-jun

2018-05-01

Rock mass undergoes some deformational failure under the action of external loads, a process known to be associated with energy dissipation and release. A triaxial loading-unloading cycle test was conducted on granite in order to investigate the energy evolution pattern of rock mass under the action of external loads. The study results demonstrated: (1) The stress peaks increased by 50% and 22% respectively and the pre-peak weakening became more apparent in the ascending process of the confining pressure from 10MPa to 30MPa; the area enclosed by the hysteresis loop corresponding to 30MPa diminished by nearly 60% than that corresponding to 10MPa, indicating a higher confining pressure prohibits rock mass from plastic deformation and shifts strain toward elastic deformation. (2) In the vicinity of the strength limit, the slope of dissipation energy increased to 1.6 from the original 0.7 and the dissipation energy grew at an accelerating rate, demonstrating stronger propagation and convergence of internal cracks. (3) At a pressure of 70% of the stress peak, the elastic energy of the granite accounted for 88% of its peak value, suggesting the rock mechanical energy from the outside mostly changes into the elastic energy inside the rock, with little energy loss.(4) Prior to test specimen failure, the axial bearing capacity dropped with a decreasing confining pressure in an essentially linear way, and the existence of confirming pressure played a role in stabilizing the axial bearing capacity.

Optimal Planning Method of On-load Capacity Regulating Distribution Transformers in Urban Distribution Networks after Electric Energy Replacement Considering Uncertainties

Directory of Open Access Journals (Sweden)

Yu Su

2018-06-01

Full Text Available Electric energy replacement is the umbrella term for the use of electric energy to replace oil (e.g., electric automobiles, coal (e.g., electric heating, and gas (e.g., electric cooking appliances, which increases the electrical load peak, causing greater valley/peak differences. On-load capacity regulating distribution transformers have been used to deal with loads with great valley/peak differences, so reasonably replacing conventional distribution transformers with on-load capacity regulating distribution transformers can effectively cope with load changes after electric energy replacement and reduce the no-load losses of distribution transformers. Before planning for on-load capacity regulating distribution transformers, the nodal effective load considering uncertainties within the life cycle after electric energy replacement was obtained by a Monte Carlo method. Then, according to the loss relation between on-load capacity regulating distribution transformers and conventional distribution transformers, three characteristic indexes of annual continuous apparent power curve and replacement criteria for on-load capacity regulating distribution transformers were put forward in this paper, and a set of distribution transformer replaceable points was obtained. Next, based on cost benefit analysis, a planning model of on-load capacity regulating distribution transformers which consists of investment profitability index within the life cycle, investment cost recouping index and capacity regulating cost index was put forward. The branch and bound method was used to solve the planning model within replaceable point set to obtain upgrading and reconstruction scheme of distribution transformers under a certain investment. Finally, planning analysis of on-load capacity regulating distribution transformers was carried out for electric energy replacement points in one urban distribution network under three scenes: certain load, uncertain load and nodal

Energy conversion through mass loading of escaping ionospheric ions for different Kp values

Science.gov (United States)

Yamauchi, Masatoshi; Slapak, Rikard

2018-01-01

By conserving momentum during the mixing of fast solar wind flow and slow planetary ion flow in an inelastic way, mass loading converts kinetic energy to other forms - e.g. first to electrical energy through charge separation and then to thermal energy (randomness) through gyromotion of the newly born cold ions for the comet and Mars cases. Here, we consider the Earth's exterior cusp and plasma mantle, where the ionospheric origin escaping ions with finite temperatures are loaded into the decelerated solar wind flow. Due to direct connectivity to the ionosphere through the geomagnetic field, a large part of this electrical energy is consumed to maintain field-aligned currents (FACs) toward the ionosphere, in a similar manner as the solar wind-driven ionospheric convection in the open geomagnetic field region. We show that the energy extraction rate by the mass loading of escaping ions (ΔK) is sufficient to explain the cusp FACs, and that ΔK depends only on the solar wind velocity accessing the mass-loading region (usw) and the total mass flux of the escaping ions into this region (mloadFload), as ΔK ˜ -mloadFloadu2sw/4. The expected distribution of the separated charges by this process also predicts the observed flowing directions of the cusp FACs for different interplanetary magnetic field (IMF) orientations if we include the deflection of the solar wind flow directions in the exterior cusp. Using empirical relations of u0 ∝ Kp + 1.2 and Fload ∝ exp(0.45Kp) for Kp = 1-7, where u0 is the solar wind velocity upstream of the bow shock, ΔK becomes a simple function of Kp as log10(ΔK) = 0.2 ṡ Kp + 2 ṡ log10(Kp + 1.2) + constant. The major contribution of this nearly linear increase is the Fload term, i.e. positive feedback between the increase of ion escaping rate Fload through the increased energy consumption in the ionosphere for high Kp, and subsequent extraction of more kinetic energy ΔK from the solar wind to the current system by the increased

Environmental assessment for DOE permission for the off-loading and transportation of commercial low-level radioactive waste across the Savannah River Site

International Nuclear Information System (INIS)

1997-10-01

The Department of Energy (DOE) prepared this Environmental Assessment (EA) to assess the potential environmental impacts associated with DOE allowing Chem-Nuclear Systems, L.L.C. (CNS) to off-load and transport low-level radioactive waste (LLW) packages across the Savannah River Site (SRS), located near Aiken, South Carolina, to the nearby CNS facility. The proposed action entails DOE granting permission to CNS to use SRS for landing shipping barges at the existing SRS boat ramp and off-loading trailered LLW packages for transportation across SRS to the CNS facility. Project activities would include modification of the SRS boat ramp on the Savannah River, as needed for off-loading activities, and construction of a bridge across Lower Three Runs. The proposed action also encompasses any similar future off-loading and transportation activities for LLW en route to the CNS facility. The National Environmental Policy Act requires the assessment of environmental consequences of Federal actions that may affect the quality of the human environment. Based on the potential for impacts described herein, DOE will either publish a Finding of No Significant Impact or prepare an Environmental Impact Statement (EIS)

Multi-Class load balancing scheme for QoS and energy ...

African Journals Online (AJOL)

Multi-Class load balancing scheme for QoS and energy conservation in cloud computing. ... If you would like more information about how to print, save, and work with PDFs, Highwire Press provides a helpful Frequently Asked Questions about PDFs. Alternatively, you can download the PDF file directly to your computer, from ...

Plastic collapse and energy absorption of circular filled tubes under quasi-static loads by computational analysis

Energy Technology Data Exchange (ETDEWEB)

Beng, Yeo Kiam; Tzeng, Woo Wen [Universiti Malaysia Sabah, Sabah (Malaysia)

2017-02-15

This study presents the finite element analysis of plastic collapse and energy absorption of polyurethane-filled aluminium circular tubes under quasi-static transverse loading. Increasing focuses were given to impact damage of structures where energy absorbed during impact could be controlled to avoid total structure collapse of energy absorbers and devices designed to dissipate energy. ABAQUS finite element analysis application was utilized for modelling and simulating the polyurethane-filled aluminium tubes, different set of diameterto- thickness ratios and span lengths, subjected to transverse three-point-bending load. Different sets of polyurethane-filled aluminium tubes subjected to the transverse loading were modelled and simulated. The failure modes and mechanisms of filled tubes and its capabilities as energy absorbers to further improve and strengthening of empty tube were also identified. The results showed that plastic deformation response was affected by the geometric constraints and parameters of the specimens. The diameter-to-thickness ratio and span lengths had shown to play crucial role in optimizing the PU-filled tube as energy absorber.

Future energy loads for a large-scale adoption of electric vehicles in the city of Los Angeles: Impacts on greenhouse gas (GHG) emissions

International Nuclear Information System (INIS)

Kim, Jae D.; Rahimi, Mansour

2014-01-01

Using plug-in electric vehicles (PEVs) has become an important component of greenhouse gas (GHG) emissions reduction strategy in the transportation sector. Assessing the net effect of PEVs on GHG emissions, however, is dependent on factors such as type and scale of electricity generation sources, adoption rate, and charging behavior. This study creates a comprehensive model that estimates the energy load and GHG emissions impacts for the years 2020 and 2030 for the city of Los Angeles. For 2020, model simulations show that the PEV charging loads will be modest with negligible effects on the overall system load profile. Contrary to previous study results, the average marginal carbon intensity is higher if PEV charging occurs during off-peak hours. These results suggest that current economic incentives to encourage off-peak charging result in greater GHG emissions. Model simulations for 2030 show that PEV charging loads increase significantly resulting in potential generation shortages. There are also significant grid operation challenges as the region's energy grid is required to ramp up and down rapidly to meet PEV loads. For 2030, the average marginal carbon intensity for off-peak charging becomes lower than peak charging mainly due to the removal of coal from the power generation portfolio. - Highlights: • Future energy load from PEV charging in the city of Los Angeles is modeled. • Changes in the marginal carbon intensity of the region's electric grid are modeled. • In the short run, offpeak charging results in higher marginal carbon intensity. • There is a mismatch between emissions and economic incentives for charging

Pay for load demand - electricity pricing with load demand component

International Nuclear Information System (INIS)

Pyrko, Jurek; Sernhed, Kerstin; Abaravicius, Juozas

2003-01-01

This publication is part of a project called Direct and Indirect Load Control in Buildings. Peak load problems have attracted considerable attention in Sweden during last three winters, caused by a significant decrease in available reserve power, which is a consequence of political decisions and liberalisation of the electricity market. A possible way to lower peak loads, avoiding electricity shortages and reducing electricity costs both for users and utilities, is to make customers experience the price difference during peak load periods and, in this way, become more aware of their energy consumption pattern and load demand. As of January 1st 2001, one of the Swedish energy utilities - Sollentuna Energi - operating in the Stockholm area, introduced a new electricity tariff with differentiated grid fees based on a mean value of the peak load every month. This tariff was introduced for all residential customers in the service area. The objective of this study is to investigate the extent to which a Load Demand Component, included in electricity pricing, can influence energy use and load demand in residential buildings. What are the benefits and disadvantages for customers and utilities? This paper investigates the impact of the new tariff on the utility and different types of typical residential customers, making comparisons with previous tariff. Keywords Load demand, electricity pricing, tariff, residential customers, energy behaviour

Dynamic loads during failure risk assessment of bridge crane structures

Science.gov (United States)

Gorynin, A. D.; Antsev, V. Yu; Shaforost, A. N.

2018-03-01

The paper presents the method of failure risk assessment associated with a bridge crane metal structure at the design stage. It also justifies the necessity of taking into account dynamic loads with regard to the operational cycle of a bridge crane during failure risk assessment of its metal structure.

Assessment of burned coal shale properties based on cyclic load

Directory of Open Access Journals (Sweden)

Grygierek Marcin

2018-01-01

Full Text Available Road surfaces that are subjected to cyclic loads generated by vehicle wheels must meet the requirements concerning the durability in the assumed period of use. The durability of the layered pavement construction systems depends on the value and frequency of the load as well as on the mechanical features of its individual layers. Layers of unbound, mechanically stabilized mixtures are a significant aspect of surfaces that are susceptible. Mixtures of this type can be applied both to the subgrade layers as well as to the bottom pavement layers, including the improved course. Considering the cyclic nature of the load on the surface of the entire system, mechanically stabilized layers are subject to continuous, but slow, densification during the period of use, which results in the formation of permanent deformations and so-called structural ruts. Post-mining waste is frequently used in road construction. which is the so-called burned shale that can be used for the bottom layers of the surface and layers of the improved subgrade (soil replacement. This material was the subject of the analysis. The evaluation was based mainly on the results of pilot studies covering cyclic loads of the layer/course made of the so-called red shale. The applied research method was aimed at preliminary assessment of its suitability for the assessment of the behaviour of the disintegrated medium under the conditions of test loads simulating the movement of vehicles.

Assessment of burned coal shale properties based on cyclic load

Science.gov (United States)

Grygierek, Marcin; Kalisz, Piotr; Pacześniowski, Krzysztof; Pytlik, Andrzej; Zięba, Magdalena

2018-04-01

Road surfaces that are subjected to cyclic loads generated by vehicle wheels must meet the requirements concerning the durability in the assumed period of use. The durability of the layered pavement construction systems depends on the value and frequency of the load as well as on the mechanical features of its individual layers. Layers of unbound, mechanically stabilized mixtures are a significant aspect of surfaces that are susceptible. Mixtures of this type can be applied both to the subgrade layers as well as to the bottom pavement layers, including the improved course. Considering the cyclic nature of the load on the surface of the entire system, mechanically stabilized layers are subject to continuous, but slow, densification during the period of use, which results in the formation of permanent deformations and so-called structural ruts. Post-mining waste is frequently used in road construction. which is the so-called burned shale that can be used for the bottom layers of the surface and layers of the improved subgrade (soil replacement). This material was the subject of the analysis. The evaluation was based mainly on the results of pilot studies covering cyclic loads of the layer/course made of the so-called red shale. The applied research method was aimed at preliminary assessment of its suitability for the assessment of the behaviour of the disintegrated medium under the conditions of test loads simulating the movement of vehicles.

Wind Climate Parameters for Wind Turbine Fatigue Load Assessment

DEFF Research Database (Denmark)

Toft, Henrik Stensgaard; Svenningsen, Lasse; Moser, Wolfgang

2016-01-01

Site-specific assessment of wind turbine design requires verification that the individual wind turbine components can survive the site-specific wind climate. The wind turbine design standard, IEC 61400-1 (third edition), describes how this should be done using a simplified, equivalent wind climate...... climate required by the current design standard by comparing damage equivalent fatigue loads estimated based on wind climate parameters for each 10 min time-series with fatigue loads estimated based on the equivalent wind climate parameters. Wind measurements from Boulder, CO, in the United States...

Coordinated Optimization of Distributed Energy Resources and Smart Loads in Distribution Systems: Preprint

Energy Technology Data Exchange (ETDEWEB)

Yang, Rui; Zhang, Yingchen

2016-08-01

Distributed energy resources (DERs) and smart loads have the potential to provide flexibility to the distribution system operation. A coordinated optimization approach is proposed in this paper to actively manage DERs and smart loads in distribution systems to achieve the optimal operation status. A three-phase unbalanced Optimal Power Flow (OPF) problem is developed to determine the output from DERs and smart loads with respect to the system operator's control objective. This paper focuses on coordinating PV systems and smart loads to improve the overall voltage profile in distribution systems. Simulations have been carried out in a 12-bus distribution feeder and results illustrate the superior control performance of the proposed approach.

Load Frequency Control of Two-Area Network using Renewable Energy Resources and Battery Energy Storage System

Directory of Open Access Journals (Sweden)

Norhafiz Bin SALIM

2017-06-01

Full Text Available In an interconnected system, the frequency and tie-line power interchange are very susceptible with the diversification of power load demand. Literally, in a multi-area power system, the load frequency control (LFC is substantially aimed to minimise the deviations of these parameters relatively. Knowingly, the power production from renewable energy resources could offer promising solutions despite their intermittency (i.e. photovoltaic/wind generation, hence in this context, a battery energy storage system (BESS is proposed to delineate dynamic response along with grid—connection. This study has proposed LFC with BESS control method to suppress frequency deviations for a power system and being compared with photovoltaic (PV approach. The effectiveness was verified using newly developed AGC30 model of Japanese Power System and was modelled using MATLAB Simulink. Furthermore, an analysis of the tie-line power oscillations also are carried out and comparison analysis demonstrates further the reliability of the proposed model and control methods.

Wind integration in self-regulating electric load distributions

Energy Technology Data Exchange (ETDEWEB)

Parkinson, Simon; Wang, Dan; Crawford, Curran; Djilali, Ned [University of Victoria, Department of Mechanical Engineering, Institute for Integrated Energy Systems, STN CSC, Victoria, BC (Canada)

2012-12-15

The purpose of this paper is to introduce and assess an alternative method of mitigating short-term wind energy production variability through the control of electric loads. In particular, co-located populations of electric vehicles and heat pumps are targeted to provide regulation-based ancillary services, as the inherent operational flexibility and autonomous device-level control strategy associated with these load-types provide an ideal platform to mitigate enhanced variability within the power system. An optimal control strategy capable of simultaneously balancing these grid-side objectives with those typically expected on the demand-side is introduced. End-use digital communication hardware is used to track and control population dynamics through the development of online aggregate load models equivalent to conventional dispatchable generation. The viability of the proposed load control strategy is assessed through model-based simulations that explicitly track end-use functionality of responsive devices within a power systems analysis typically implemented to observe the effects of integrated wind energy systems. Results indicate that there is great potential for the proposed method to displace the need for increased online regulation reserve capacity in systems considering a high penetration of wind energy, thereby allowing conventional generation to operate more efficiently. (orig.)

Load Balancing Integrated Least Slack Time-Based Appliance Scheduling for Smart Home Energy Management.

Science.gov (United States)

Silva, Bhagya Nathali; Khan, Murad; Han, Kijun

2018-02-25

The emergence of smart devices and smart appliances has highly favored the realization of the smart home concept. Modern smart home systems handle a wide range of user requirements. Energy management and energy conservation are in the spotlight when deploying sophisticated smart homes. However, the performance of energy management systems is highly influenced by user behaviors and adopted energy management approaches. Appliance scheduling is widely accepted as an effective mechanism to manage domestic energy consumption. Hence, we propose a smart home energy management system that reduces unnecessary energy consumption by integrating an automated switching off system with load balancing and appliance scheduling algorithm. The load balancing scheme acts according to defined constraints such that the cumulative energy consumption of the household is managed below the defined maximum threshold. The scheduling of appliances adheres to the least slack time (LST) algorithm while considering user comfort during scheduling. The performance of the proposed scheme has been evaluated against an existing energy management scheme through computer simulation. The simulation results have revealed a significant improvement gained through the proposed LST-based energy management scheme in terms of cost of energy, along with reduced domestic energy consumption facilitated by an automated switching off mechanism.

Load Balancing Integrated Least Slack Time-Based Appliance Scheduling for Smart Home Energy Management

Science.gov (United States)

Silva, Bhagya Nathali; Khan, Murad; Han, Kijun

2018-01-01

The emergence of smart devices and smart appliances has highly favored the realization of the smart home concept. Modern smart home systems handle a wide range of user requirements. Energy management and energy conservation are in the spotlight when deploying sophisticated smart homes. However, the performance of energy management systems is highly influenced by user behaviors and adopted energy management approaches. Appliance scheduling is widely accepted as an effective mechanism to manage domestic energy consumption. Hence, we propose a smart home energy management system that reduces unnecessary energy consumption by integrating an automated switching off system with load balancing and appliance scheduling algorithm. The load balancing scheme acts according to defined constraints such that the cumulative energy consumption of the household is managed below the defined maximum threshold. The scheduling of appliances adheres to the least slack time (LST) algorithm while considering user comfort during scheduling. The performance of the proposed scheme has been evaluated against an existing energy management scheme through computer simulation. The simulation results have revealed a significant improvement gained through the proposed LST-based energy management scheme in terms of cost of energy, along with reduced domestic energy consumption facilitated by an automated switching off mechanism. PMID:29495346

Load Balancing Integrated Least Slack Time-Based Appliance Scheduling for Smart Home Energy Management

Directory of Open Access Journals (Sweden)

Bhagya Nathali Silva

2018-02-01

Full Text Available The emergence of smart devices and smart appliances has highly favored the realization of the smart home concept. Modern smart home systems handle a wide range of user requirements. Energy management and energy conservation are in the spotlight when deploying sophisticated smart homes. However, the performance of energy management systems is highly influenced by user behaviors and adopted energy management approaches. Appliance scheduling is widely accepted as an effective mechanism to manage domestic energy consumption. Hence, we propose a smart home energy management system that reduces unnecessary energy consumption by integrating an automated switching off system with load balancing and appliance scheduling algorithm. The load balancing scheme acts according to defined constraints such that the cumulative energy consumption of the household is managed below the defined maximum threshold. The scheduling of appliances adheres to the least slack time (LST algorithm while considering user comfort during scheduling. The performance of the proposed scheme has been evaluated against an existing energy management scheme through computer simulation. The simulation results have revealed a significant improvement gained through the proposed LST-based energy management scheme in terms of cost of energy, along with reduced domestic energy consumption facilitated by an automated switching off mechanism.

Performance improvement of a battery/PV/fuel cell/grid hybrid energy system considering load uncertainty modeling using IGDT

International Nuclear Information System (INIS)

Nojavan, Sayyad; Majidi, Majid; Zare, Kazem

2017-01-01

Highlights: • Optimum performance of PV/battery/fuel cell/grid hybrid system under load uncertainty. • Employing information gap decision theory (IGDT) to model the load uncertainty. • Robustness and opportunity functions of IGDT are modeled for risk-averse and risk-taker. • Robust strategy of hybrid system's operation obtained from robustness function. • Opportunistic strategy of hybrid system's operation obtained from opportunity function. - Abstract: Nowadays with the speed that electrical loads are growing, system operators are challenged to manage the sources they use to supply loads which means that that besides upstream grid as the main sources of electric power, they can utilize renewable and non-renewable energy sources to meet the energy demand. In the proposed paper, a photovoltaic (PV)/fuel cell/battery hybrid system along with upstream grid has been utilized to supply two different types of loads: electrical load and thermal load. Operators should have to consider load uncertainty to manage the strategies they employ to supply load. In other words, operators have to evaluate how load variation would affect their energy procurement strategies. Therefore, information gap decision theory (IGDT) technique has been proposed to model the uncertainty of electrical load. Utilizing IGDT approach, robustness and opportunity functions are achieved which can be used by system operator to take the appropriate strategy. The uncertainty modeling of load enables operator to make appropriate decisions to optimize the system’s operation against possible changes in load. A case study has been simulated to validate the effects of proposed technique.

Energy conversion through mass loading of escaping ionospheric ions for different Kp values

Directory of Open Access Journals (Sweden)

M. Yamauchi

2018-01-01

Full Text Available By conserving momentum during the mixing of fast solar wind flow and slow planetary ion flow in an inelastic way, mass loading converts kinetic energy to other forms – e.g. first to electrical energy through charge separation and then to thermal energy (randomness through gyromotion of the newly born cold ions for the comet and Mars cases. Here, we consider the Earth's exterior cusp and plasma mantle, where the ionospheric origin escaping ions with finite temperatures are loaded into the decelerated solar wind flow. Due to direct connectivity to the ionosphere through the geomagnetic field, a large part of this electrical energy is consumed to maintain field-aligned currents (FACs toward the ionosphere, in a similar manner as the solar wind-driven ionospheric convection in the open geomagnetic field region. We show that the energy extraction rate by the mass loading of escaping ions (ΔK is sufficient to explain the cusp FACs, and that ΔK depends only on the solar wind velocity accessing the mass-loading region (usw and the total mass flux of the escaping ions into this region (mloadFload, as ΔK ∼ −mloadFloadu2sw∕4. The expected distribution of the separated charges by this process also predicts the observed flowing directions of the cusp FACs for different interplanetary magnetic field (IMF orientations if we include the deflection of the solar wind flow directions in the exterior cusp. Using empirical relations of u0 ∝ Kp + 1.2 and Fload ∝ exp(0.45Kp for Kp = 1–7, where u0 is the solar wind velocity upstream of the bow shock, ΔK becomes a simple function of Kp as log10(ΔK = 0.2 ⋅ Kp + 2 ⋅ log10(Kp + 1.2 + constant. The major contribution of this nearly linear increase is the Fload term, i.e. positive feedback between the increase of ion escaping rate Fload through the increased energy consumption in the ionosphere for high Kp, and subsequent extraction of more kinetic energy �

Assessment of the Charging Policy in Energy Efficiency of the Enterprise

Science.gov (United States)

Shutov, E. A.; E Turukina, T.; Anisimov, T. S.

2017-04-01

The forecasting problem for energy facilities with a power exceeding 670 kW is currently one of the main. In connection with rules of the retail electricity market such customers also pay for actual energy consumption deviations from plan value. In compliance with the hierarchical stages of the electricity market a guaranteeing supplier is to respect the interests of distribution and generation companies that require load leveling. The answer to this question for industrial enterprise is possible only within technological process through implementation of energy-efficient processing chains with the adaptive function and forecasting tool. In such a circumstance the primary objective of a forecasting is reduce the energy consumption costs by taking account of the energy cost correlation for 24 hours for forming of pumping unit work schedule. The pumping unit virtual model with the variable frequency drive is considered. The forecasting tool and the optimizer are integrated into typical control circuit. Economic assessment of the optimization method was estimated.

Alternative test method to assess the energy performance of frost-free refrigerating appliances

International Nuclear Information System (INIS)

Hermes, Christian J.L.; Melo, Cláudio; Knabben, Fernando T.

2013-01-01

This paper outlines an alternative test method to evaluate the energy consumption of frost-free refrigerators and freezers for residential applications. While the standardized methods require the refrigerating appliance to be kept running according to its onboard control system, which usually drives the refrigerator through an on–off cycling pattern, the proposed approach assesses the refrigerator energy performance in the steady-state regime, being therefore much faster and more reliable. In this procedure, the cooling capacity is matched to the cooling loads by PID-controlled electrical heaters installed within the refrigerated compartments, so that the compartment temperatures are kept at the desired standardized levels. Comparisons between the experimental results obtained using the steady-state energy test and the standardized procedures showed that the former follows closely the trends observed for the latter. - Highlights: ► An alternative test method to assess the energy consumption of refrigerators is proposed. ► PID-controlled electrical heaters were installed within the compartments. ► Steady-state and ISO energy tests were performed and compared. ► Both proposed and standardized test procedures showed similar trends.

A multi-objective genetic approach to domestic load scheduling in an energy management system

International Nuclear Information System (INIS)

Soares, Ana; Antunes, Carlos Henggeler; Oliveira, Carlos; Gomes, Álvaro

2014-01-01

In this paper a multi-objective genetic algorithm is used to solve a multi-objective model to optimize the time allocation of domestic loads within a planning period of 36 h, in a smart grid context. The management of controllable domestic loads is aimed at minimizing the electricity bill and the end-user’s dissatisfaction concerning two different aspects: the preferred time slots for load operation and the risk of interruption of the energy supply. The genetic algorithm is similar to the Elitist NSGA-II (Nondominated Sorting Genetic Algorithm II), in which some changes have been introduced to adapt it to the physical characteristics of the load scheduling problem and improve usability of results. The mathematical model explicitly considers economical, technical, quality of service and comfort aspects. Illustrative results are presented and the characteristics of different solutions are analyzed. - Highlights: • A genetic algorithm similar to the NSGA-II is used to solve a multi-objective model. • The optimized time allocation of domestic loads in a smart grid context is achieved. • A variable preference profile for the operation of the managed loads is included. • A safety margin is used to account for the quality of the energy services provided. • A non-dominated front with the solutions in the two-objective space is obtained

Design Load Basis for Offshore Wind turbines

DEFF Research Database (Denmark)

Natarajan, Anand; Hansen, Morten Hartvig; Wang, Shaofeng

2016-01-01

DTU Wind Energy is not designing and manufacturing wind turbines and does therefore not need a Design Load Basis (DLB) that is accepted by a certification body. However, to assess the load consequences of innovative features and devices added to existing offshore turbine concepts or new offshore...... turbine concept developed in our research, it is useful to have a full DLB that follows the current design standard and is representative of a general DLB used by the industry. It will set a standard for the offshore wind turbine design load evaluations performed at DTU Wind Energy, which is aligned...... with the challenges faced by the industry and therefore ensures that our research continues to have a strong foundation in this interaction. Furthermore, the use of a full DLB that follows the current standard can improve and increase the feedback from the research at DTU Wind Energy to the international...

Experimental study of plasma energy transfer and material erosion under ELM-like heat loads

Energy Technology Data Exchange (ETDEWEB)

Garkusha, I.E., E-mail: garkusha@ipp.kharkov.u [Institute of Plasma Physics of the NSC KIPT, Akademicheskaya 1, 61108 Kharkov (Ukraine); Makhlaj, V.A.; Chebotarev, V.V. [Institute of Plasma Physics of the NSC KIPT, Akademicheskaya 1, 61108 Kharkov (Ukraine); Landman, I. [Forschungszentrum Karlsruhe, IHM, 76021 Karlsruhe (Germany); Tereshin, V.I.; Aksenov, N.N.; Bandura, A.N. [Institute of Plasma Physics of the NSC KIPT, Akademicheskaya 1, 61108 Kharkov (Ukraine)

2009-06-15

Main features of plasma-surface interaction and energy transfer to tokamak plasma facing components are studied at different heat loads in ELM simulation experiments with the plasma gun QSPA Kh-50. Repetitive plasma exposures of tungsten, graphite and different combined W-C targets were performed at the pulse duration of 0.25 ms and the heat loads varied in the range 0.2-2.5 MJ/m{sup 2}. The onset of vapor shield in front of the surface was investigated. The evaporation is immediately followed by a saturation of surface heat load if further increasing the impact energy. The presence of graphite essentially decreases the heat flux to the nearby tungsten surface, which is due to the carbon vapor shield. Droplet splashing at the tungsten surface and formation of hot spots on the graphite surface are discussed.

Experimental study of plasma energy transfer and material erosion under ELM-like heat loads

International Nuclear Information System (INIS)

Garkusha, I.E.; Makhlaj, V.A.; Chebotarev, V.V.; Landman, I.; Tereshin, V.I.; Aksenov, N.N.; Bandura, A.N.

2009-01-01

Main features of plasma-surface interaction and energy transfer to tokamak plasma facing components are studied at different heat loads in ELM simulation experiments with the plasma gun QSPA Kh-50. Repetitive plasma exposures of tungsten, graphite and different combined W-C targets were performed at the pulse duration of 0.25 ms and the heat loads varied in the range 0.2-2.5 MJ/m 2 . The onset of vapor shield in front of the surface was investigated. The evaporation is immediately followed by a saturation of surface heat load if further increasing the impact energy. The presence of graphite essentially decreases the heat flux to the nearby tungsten surface, which is due to the carbon vapor shield. Droplet splashing at the tungsten surface and formation of hot spots on the graphite surface are discussed.

Validation of Simplified Load Equations Through Loads Measurement and Modeling of a Small Horizontal-Axis Wind Turbine Tower

Energy Technology Data Exchange (ETDEWEB)

Dana, Scott [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Van Dam, Jeroen J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Damiani, Rick R [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2018-04-24

As part of an ongoing effort to improve the modeling and prediction of small wind turbine dynamics, the National Renewable Energy Laboratory (NREL) tested a small horizontal-axis wind turbine in the field at the National Wind Technology Center. The test turbine was a 2.1-kW downwind machine mounted on an 18-m multi-section fiberglass composite tower. The tower was instrumented and monitored for approximately 6 months. The collected data were analyzed to assess the turbine and tower loads and further validate the simplified loads equations from the International Electrotechnical Commission (IEC) 61400-2 design standards. Field-measured loads were also compared to the output of an aeroelastic model of the turbine. In particular, we compared fatigue loads as measured in the field, predicted by the aeroelastic model, and calculated using the simplified design equations. Ultimate loads at the tower base were assessed using both the simplified design equations and the aeroelastic model output. The simplified design equations in IEC 61400-2 do not accurately model fatigue loads and a discussion about the simplified design equations is discussed.

Scheduling algorithms for saving energy and balancing load

Energy Technology Data Exchange (ETDEWEB)

Antoniadis, Antonios

2012-08-03

In this thesis we study problems of scheduling tasks in computing environments. We consider both the modern objective function of minimizing energy consumption, and the classical objective of balancing load across machines. We first investigate offline deadline-based scheduling in the setting of a single variable-speed processor that is equipped with a sleep state. The objective is that of minimizing the total energy consumption. Apart from settling the complexity of the problem by showing its NP-hardness, we provide a lower bound of 2 for general convex power functions, and a particular natural class of schedules called s{sub crit}-schedules. We also present an algorithmic framework for designing good approximation algorithms. For general convex power functions our framework improves the best known approximation-factor from 2 to 4/3. This factor can be reduced even further to 137/117 for a specific well-motivated class of power functions. Furthermore, we give tight bounds to show that our framework returns optimal s{sub crit}-schedules for the two aforementioned power-function classes. We then focus on the multiprocessor setting where each processor has the ability to vary its speed. Job migration is allowed, and we again consider classical deadline-based scheduling with the objective of energy minimization. We first study the offline problem and show that optimal schedules can be computed efficiently in polynomial time for any convex and non-decreasing power function. Our algorithm relies on repeated maximum flow computations. Regarding the online problem and power functions P(s) = s{sup {alpha}}, where s is the processor speed and {alpha} > 1 a constant, we extend the two well-known single-processor algorithms Optimal Available and Average Rate. We prove that Optimal Available is {alpha}{sup {alpha}}-competitive as in the single-processor case. For Average Rate we show a competitive factor of (2{alpha}){sup {alpha}}/2 + 1, i.e., compared to the single

Long term building energy demand for India: Disaggregating end use energy services in an integrated assessment modeling framework

International Nuclear Information System (INIS)

Chaturvedi, Vaibhav; Eom, Jiyong; Clarke, Leon E.; Shukla, Priyadarshi R.

2014-01-01

With increasing population, income, and urbanization, meeting the energy service demands for the building sector will be a huge challenge for Indian energy policy. Although there is broad consensus that the Indian building sector will grow and evolve over the coming century, there is little understanding of the potential nature of this evolution over the longer term. The present study uses a technologically detailed, service based building energy model nested in the long term, global, integrated assessment framework, GCAM, to produce scenarios of the evolution of the Indian buildings sector up through the end of the century. The results support the idea that as India evolves toward developed country per-capita income levels, its building sector will largely evolve to resemble those of the currently developed countries (heavy reliance on electricity both for increasing cooling loads and a range of emerging appliance and other plug loads), albeit with unique characteristics based on its climate conditions (cooling dominating heating and even more so with climate change), on fuel preferences that may linger from the present (for example, a preference for gas for cooking), and vestiges of its development path (including remnants of rural poor that use substantial quantities of traditional biomass). - Highlights: ► Building sector final energy demand in India will grow to over five times by century end. ► Space cooling and appliance services will grow substantially in the future. ► Energy service demands will be met predominantly by electricity and gas. ► Urban centers will face huge demand for floor space and building energy services. ► Carbon tax policy will have little effect on reducing building energy demands

Online Voltage Stability Assessment for Load Areas Based on the Holomorphic Embedding Method

DEFF Research Database (Denmark)

Liu, Chengxi; Wang, Bin; Hu, Fengkai

2018-01-01

This paper proposes an online steady-state voltage stability assessment scheme to evaluate the proximity to voltage collapse at each bus of a load area. Using a non-iterative holomorphic embedding method (HEM) with a proposed physical germ solution, an accurate loading limit at each load bus can...... be calculated based on online state estimation on the entire load area and a measurement-based equivalent for the external system. The HEM employs a power series to calculate an accurate Power-Voltage (P-V) curve at each load bus and accordingly evaluates the voltage stability margin considering load variations...... and then demonstrated on a load area of the Northeast Power Coordinating Council (NPCC) 48-generator, 140-bus power system....

An energy estimation framework for event-based methods in Non-Intrusive Load Monitoring

International Nuclear Information System (INIS)

Giri, Suman; Bergés, Mario

2015-01-01

Highlights: • Energy estimation is NILM has not yet accounted for complexity of appliance models. • We present a data-driven framework for appliance modeling in supervised NILM. • We test the framework on 3 houses and report average accuracies of 5.9–22.4%. • Appliance models facilitate the estimation of energy consumed by the appliance. - Abstract: Non-Intrusive Load Monitoring (NILM) is a set of techniques used to estimate the electricity consumed by individual appliances in a building from measurements of the total electrical consumption. Most commonly, NILM works by first attributing any significant change in the total power consumption (also known as an event) to a specific load and subsequently using these attributions (i.e. the labels for the events) to estimate energy for each load. For this last step, most published work in the field makes simplifying assumptions to make the problem more tractable. In this paper, we present a framework for creating appliance models based on classification labels and aggregate power measurements that can help to relax many of these assumptions. Our framework automatically builds models for appliances to perform energy estimation. The model relies on feature extraction, clustering via affinity propagation, perturbation of extracted states to ensure that they mimic appliance behavior, creation of finite state models, correction of any errors in classification that might violate the model, and estimation of energy based on corrected labels. We evaluate our framework on 3 houses from standard datasets in the field and show that the framework can learn data-driven models based on event labels and use that to estimate energy with lower error margins (e.g., 1.1–42.3%) than when using the heuristic models used by others

An optimal control model for load shifting - With application in the energy management of a colliery

International Nuclear Information System (INIS)

Middelberg, Arno; Zhang Jiangfeng; Xia Xiaohua

2009-01-01

This paper presents an optimal control model for the load shifting problem in energy management and its application in a South African colliery. It is illustrated in the colliery scenario that how the optimal control model can be applied to optimize load shifting and improve energy efficiency through the control of conveyor belts. The time-of-use electricity tariff is used as an input to the objective function in order to obtain a solution that minimizes electricity costs and thus maximizes load shifting. The case study yields promising results that show the potential of applying this optimal control model to other industrial Demand Side Management initiatives

Handbook of five methodologies for the assessment of load management

Energy Technology Data Exchange (ETDEWEB)

1980-02-01

This report provides a summary description and evaluation of five methodologies that have been developed for the assessment of utility costs and benefits of load-management programs, including marginal-costing methodologies and an integrated set of utility-system planning and production costing models. Of the two basic methods, the first uses marginal-cost data to compute the cumulative reduction in utility-system costs realized in moving units of load from periods of high marginal cost to periods of low marginal cost. The present value of these cost savings may be compared directly with the costs of implementing the load-management program. The second method relies on an evaluation of future total-system costs. System planning and production-costing models are used to calculate the total fixed and variable costs of meeting baseline and alternative-load configurations. The difference between baseline system costs and the costs with load management may then be compared to the costs of implementing the program. The advantages and disadvantages of each method are summarized briefly.

Cognitive Load in Mild Traumatic Brain Injury: A Pupillometric Assessment of Multiple Attentional Processes

Science.gov (United States)

2016-05-20

Hershaw Thesis submitted to the Faculty of the Medical Psychology Graduate Program Uniformed Services University of the Health ...system while completing a task. The amount of mental effort and cognitive resources required to complete a task depends on cognitive load. Thus, the...load and require greater mental effort for people with mild TBI. PUPILLOMETRIC ASSESSMENT OF COGNITIVE LOAD Differences in cognitive load in

ANALYSIS OF ENERGY EFFICIENCY OF OPERATING MODES OF ELECTRICAL SYSTEMS WITH THE TRACTION LOADS

Directory of Open Access Journals (Sweden)

V. E. Bondarenko

2017-03-01

Full Text Available Innovative scenarios of reliable energy supply of transportation process aimed at reducing the specific energy consumption and increase energy efficiency of the systems of electric traction. The paper suggests innovative energy saving directions in traction networks of railways and new circuit solutions accessing traction substations in energy systems networks, ensure energy security of the transportation process. To ensure the energy security of rail transport special schemes were developed to propose the concept of external power traction substations, which would increase the number of connections to the networks of 220 – 330 kV, as well as the creation of transport and energy corridors, development of its own supply of electric networks of 110 kV substations and mobile RP-110 kV of next generation. Therefore, the investment program of the structures owned by the Ukrainian Railways (Ukrzaliznytsia need to be synchronized in their technological characteristics, as well as the criteria of reliability and quality of power supply with the same external energy investment programs. It is found that without any load on left or right supplying arm one of two less loaded phases of traction transformer begins generating specific modes in the supplying three-phase line. Thus, modes of mobile substation cause leakage in one of the phases of the supply line of traction transformers of active-capacitive current, and as a result generating energy in the main power line of 154 kV, which is fixed and calculated by electricity meters. For these three phase mode supply network is necessary to use 1st algorithm, i.e. taking into account the amount of electricity as the energy in all phases. For effective application of reactive power compensation devices in the AC traction power supply systems it is proposed to develop regulatory documentation on necessity of application and the order of choice of parameters and placement of compensation systems taking into

Technical and economic assessment of fluidized-bed-augmented compressed-air energy-storage system. Volume I. Executive summary

Energy Technology Data Exchange (ETDEWEB)

Giramonti, A.J.; Lessard, R.D.; Merrick, D.; Hobson, M.J.

1981-09-01

An energy storage system which could be attractive for future electric utility peak-load applications is a modified gas turbine power system utilizing underground storage of very high pressure air. The compressed air energy storage (CAES) concept involves using off-peak electricity generated from indigenous coal or nuclear sources to compress air, storing the air in large underground facilities, and withdrawing the air during peak-load periods when it would be heated by combustion and expanded through gas turbines to generate power. The attractiveness of the CAES concept is based upon its potential to supply competitively priced peaking energy, to reduce peak-load power plant dependence on petroleum-based fuels, and to provide a means for leveling the utility system load demand. Therefore, a technical and economic assessment of coal-fired fluidized bed (FBC) combustor/compressed air energy storage (FBC/CAES) systems was performed and is described. The conclusions drawn from the FBC/CAES study program are encouraging. They indicate that pressurized FBC/CAES power plants should be technologically feasible, provide good performance, and be economically competitive. Specifically, it is concluded that: coal-fired FBC/CAES systems should be technically feasible in the near future and potentially attractive for peak-load power generation; and an open-bed PFBC/CAES configuration would provide the best candidate for early commercialization. It has relatively low risk combined with moderate cost and reasonable round-trip heat rate. It also has the potential for future growth options which tend to reduce costs and lower fuel consumption.

The pizzicato knee-joint energy harvester: characterization with biomechanical data and the effect of backpack load

International Nuclear Information System (INIS)

Pozzi, Michele; Zhu, Meiling; Aung, Min S H; Goulermas, John Y; Jones, Richard K

2012-01-01

The reduced power requirements of miniaturized electronics offer the opportunity to create devices which rely on energy harvesters for their power supply. In the case of wearable devices, human-based piezoelectric energy harvesting is particularly difficult due to the mismatch between the low frequency of human activities and the high-frequency requirements of piezoelectric transducers. We propose a piezoelectric energy harvester, to be worn on the knee-joint, that relies on the plucking technique to achieve frequency up-conversion. During a plucking action, a piezoelectric bimorph is deflected by a plectrum; when released due to loss of contact, the bimorph is free to vibrate at its resonant frequency, generating electrical energy with the highest efficiency. A prototype, featuring four PZT-5H bimorphs, was built and is here studied in a knee simulator which reproduces the gait of a human subject. Biomechanical data were collected with a marker-based motion capture system while the subject was carrying a selection of backpack loads. The paper focuses on the energy generation of the harvester and how this is affected by the backpack load. By altering the gait, the backpack load has a measurable effect on performance: at the highest load of 24 kg, a minor reduction in energy generation (7%) was observed and the output power is reduced by 10%. Both are so moderate to be practically unimportant. The average power output of the prototype is 2.06 ± 0.3 mW, which can increase significantly with further optimization. (paper)

Data from renewable energy assessments for resort islands in the South China Sea.

Science.gov (United States)

Basir Khan, M Reyasudin; Jidin, Razali; Pasupuleti, Jagadeesh

2016-03-01

Renewable energy assessments for resort islands in the South China Sea were conducted that involves the collection and analysis of meteorological and topographic data. The meteorological data was used to assess the PV, wind and hydropower system potentials on the islands. Furthermore, the reconnaissance study for hydro-potentials were conducted through topographic maps in order to determine the potential sites suitable for development of run-of-river hydropower generation. The stream data was collected for 14 islands in the South China Sea with a total of 51 investigated sites. The data from this study are related to the research article "Optimal combination of solar, wind, micro-hydro and diesel systems based on actual seasonal load profiles for a resort island in the South China Sea" published in Energy (Khan et al., 2015) [1].

Assessment of Methods to Consolidate Iodine-Loaded Silver-Functionalized Silica Aerogel

Energy Technology Data Exchange (ETDEWEB)

Matyas, Josef; Engler, Robert K.

2013-09-01

The U.S. Department of Energy is currently investigating alternative sorbents for the removal and immobilization of radioiodine from the gas streams in a nuclear fuel reprocessing plant. One of these new sorbents, Ag0-functionalized silica aerogels, shows great promise as a potential replacement for Ag-bearing mordenites because of its high selectivity and sorption capacity for iodine. Moreover, a feasible consolidation of iodine-loaded Ag0-functionalized silica aerogels to a durable SiO2-based waste form makes this aerogel an attractive choice for sequestering radioiodine. This report provides a preliminary assessment of the methods that can be used to consolidate iodine-loaded Ag0-functionalized silica aerogels into a final waste form. In particular, it focuses on experimental investigation of densification of as prepared Ag0-functionalized silica aerogels powders, with or without organic moiety and with or without sintering additive (colloidal silica), with three commercially available techniques: 1) hot uniaxial pressing (HUP), 2) hot isostatic pressing (HIP), and 3) spark plasma sintering (SPS). The densified products were evaluated with helium gas pycnometer for apparent density, with the Archimedes method for apparent density and open porosity, and with high-resolution scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS) for the extent of densification and distribution of individual elements. The preliminary investigation of HUP, HIP, and SPS showed that these sintering methods can effectively consolidate powders of Ag0-functionalized silica aerogel into products of near-theoretical density. Also, removal of organic moiety and adding 5.6 mass% of colloidal silica to Ag0-functionalized silica aerogel powders before processing provided denser products. Furthermore, the ram travel data for SPS indicated that rapid consolidation of powders can be performed at temperatures below 950°C.

Vulnerability Assessment for a Complex Structure Using Vibration Response Induced by Impact Load

International Nuclear Information System (INIS)

Park, Jeongwon; Park, Junhong; Koo, Man Hoi

2014-01-01

This work presents a vulnerability assessment procedure for a complex structure using vibration characteristics. The structural behavior of a three-dimensional framed structure subjected to impact forces was predicted using the spectral element method. The Timoshenko beam function was applied to simulate the impact wave propagations induced by a high-velocity projectile at relatively high frequencies. The interactions at the joints were analyzed for both flexural and longitudinal wave propagations. Simulations of the impact energy transfer through the entire structure were performed using the transient displacement and acceleration responses obtained from the frequency analysis. The kill probabilities of the crucial components for an operating system were calculated as a function of the predicted acceleration amplitudes according to the acceptable vibration levels. Following the proposed vulnerability assessment procedure, the vulnerable positions of a three-dimensional combat vehicle with high possibilities of damage generation of components by impact loading were identified from the estimated vibration responses

Analytic model for ultrasound energy receivers and their optimal electric loads

Science.gov (United States)

Gorostiaga, M.; Wapler, M. C.; Wallrabe, U.

2017-08-01

In this paper, we present an analytic model for thickness resonating plate ultrasound energy receivers, which we have derived from the piezoelectric and the wave equations and, in which we have included dielectric, viscosity and acoustic attenuation losses. Afterwards, we explore the optimal electric load predictions by the zero reflection and power maximization approaches present in the literature with different acoustic boundary conditions, and discuss their limitations. To validate our model, we compared our expressions with the KLM model solved numerically with very good agreement. Finally, we discuss the differences between the zero reflection and power maximization optimal electric loads, which start to differ as losses in the receiver increase.

A Study on Assessment Method of Traffic Load Effect of Bridge in Service

Science.gov (United States)

Ling, Pan; Dajian, Han

2010-05-01

Because of overloading usually occur in highway in China today, it is found that the traffic load and the load effects given by Specification for Inspection and Evaluation of Load-bearing Capacity of Highway Bridge[1] cannot be adequately estimated. Especially, the extreme values in a service period can not be predicted. In this paper, a model is first developed for a better estimation of the actual traffic flow, as well as the service load effect level of a bridge. Based on a five-day collection data of the vehicle samples passing through the exit of Guangyuan to Shahe of the North-Ring Highway in Guangzhou, The Qiaole Bridge of the highway is taken as an example to illustrate the assessment model. Then, a threshold model is applied to estimate the tail distribution of the maximum load effect of a fleet. And threshold point process is used to infer the maximum value distribution for prediction of the load effect level of the bridge in a future time period. Finally, a 0.95 quantile is obtained to compare with the result given by specification[1]. The results show that the assessment method proposed in this paper is valid and feasible.

An Improved Flexible Solar Thermal Energy Integration Process for Enhancing the Coal-Based Energy Efficiency and NOx Removal Effectiveness in Coal-Fired Power Plants under Different Load Conditions

Directory of Open Access Journals (Sweden)

Yu Han

2017-09-01

Full Text Available An improved flexible solar-aided power generation system (SAPG for enhancing both selective catalytic reduction (SCR de-NOx efficiency and coal-based energy efficiency of coal-fired power plants is proposed. In the proposed concept, the solar energy injection point is changed for different power plant loads, bringing about different benefits for coal-fired power generation. For partial/low load, solar energy is beneficially used to increase the flue gas temperature to guarantee the SCR de-NOx effectiveness as well as increase the boiler energy input by reheating the combustion air. For high power load, solar energy is used for saving steam bleeds from turbines by heating the feed water. A case study for a typical 1000 MW coal-fired power plant using the proposed concept has been performed and the results showed that, the SCR de-NOx efficiency of proposed SAPG could increase by 3.1% and 7.9% under medium load and low load conditions, respectively, as compared with the reference plant. The standard coal consumption rate of the proposed SAPG could decrease by 2.68 g/kWh, 4.05 g/kWh and 6.31 g/kWh for high, medium and low loads, respectively, with 0.040 USD/kWh of solar generated electricity cost. The proposed concept opens up a novel solar energy integration pattern in coal-fired power plants to improve the pollutant removal effectiveness and decrease the coal consumption of the power plant.

Data from renewable energy assessments for resort islands in the South China Sea

Directory of Open Access Journals (Sweden)

M. Reyasudin Basir Khan

2016-03-01

Full Text Available Renewable energy assessments for resort islands in the South China Sea were conducted that involves the collection and analysis of meteorological and topographic data. The meteorological data was used to assess the PV, wind and hydropower system potentials on the islands. Furthermore, the reconnaissance study for hydro-potentials were conducted through topographic maps in order to determine the potential sites suitable for development of run-of-river hydropower generation. The stream data was collected for 14 islands in the South China Sea with a total of 51 investigated sites. The data from this study are related to the research article “Optimal combination of solar, wind, micro-hydro and diesel systems based on actual seasonal load profiles for a resort island in the South China Sea” published in Energy (Khan et al., 2015 [1]. Keywords: South China Sea, Solar radiation,wind speed, rainfall, microhydropower, PV system, Wind energy generation system

Study of the energy gain and the beam loading of the detuned structure with a simple model

International Nuclear Information System (INIS)

Heifets, S.A.; Kheifets, S.A.

1993-01-01

A circuit model for the longitudinal case from which to study the field pattern, energy gain and beam loading of a detuned structure is derived from Maxwell's equations. The results obtained with the model are compared to numerical results of the code PROGON. The model gives reasonable scaling of the group velocity and voltage with geometric parameters. The energy gain and beam loading are compared and are shown to depend on the same factor. This is true even for periodic variations of the boundary. Finally, a way to find the shape of the rf pulse envelope for the beam loading compensation is suggested

The Effects of Triggering Mechanisms on the Energy Absorption Capability of Circular Jute/Epoxy Composite Tubes under Quasi-Static Axial Loading

Science.gov (United States)

Sivagurunathan, Rubentheran; Lau Tze Way, Saijod; Sivagurunathan, Linkesvaran; Yaakob, Mohd. Yuhazri

2018-01-01

The usage of composite materials have been improving over the years due to its superior mechanical properties such as high tensile strength, high energy absorption capability, and corrosion resistance. In this present study, the energy absorption capability of circular jute/epoxy composite tubes were tested and evaluated. To induce the progressive crushing of the composite tubes, four different types of triggering mechanisms were used which were the non-trigger, single chamfered trigger, double chamfered trigger and tulip trigger. Quasi-static axial loading test was carried out to understand the deformation patterns and the load-displacement characteristics for each composite tube. Besides that, the influence of energy absorption, crush force efficiency, peak load, mean load and load-displacement history were examined and discussed. The primary results displayed a significant influence on the energy absorption capability provided that stable progressive crushing occurred mostly in the triggered tubes compared to the non-triggered tubes. Overall, the tulip trigger configuration attributed the highest energy absorption.

Assessment of infiltration heat recovery and its impact on energy consumption for residential buildings

International Nuclear Information System (INIS)

Solupe, Mikel; Krarti, Moncef

2014-01-01

Highlights: • Five steady-state air infiltration heat recovery or IHR models are described and compared. • IHR models are incorporated within whole-building simulation analysis tool. • IHR can reduce the thermal loads of residential buildings by 5–30%. - Abstract: Infiltration is a major contributor to the energy consumption of buildings, particularly in homes where it accounts for one-third of the heating and cooling loads. Traditionally, infiltration is calculated independent of the building envelope performance, however, it has been established that a thermal coupling exists between the infiltration and conduction heat transfer of the building envelope. This effect is known as infiltration heat recovery (IHR). Experiments have shown that infiltration heat recovery can typically reduce the infiltration thermal load by 10–20%. Currently, whole-building energy simulation tools do not account for the effect of infiltration heat recovery on heating and cooling loads. In this paper, five steady-state IHR models are described to account for the thermal interaction between infiltration air and building envelope components. In particular, inter-model and experimental comparisons are carried out to assess the prediction accuracy of five IHR models. In addition, the results from a series of sensitivity analyses are presented, including an evaluation of the predictions for heating energy use associated with four audited homes obtained from whole-building energy simulation analysis with implemented infiltration heat recovery models. Experimental comparison of the IHR models reveal that the predictions from all the five models are consistent and are within 2% when 1-D flow and heat transfer conditions are considered. When implementing IHR models to a whole-building simulation environment, a reduction of 5–30% in heating consumption is found for four audited residential homes

Assessing Cognitive Load Theory to Improve Student Learning for Mechanical Engineers

Science.gov (United States)

Impelluso, Thomas J.

2009-01-01

A computer programming class for students of mechanical engineering was redesigned and assessed: Cognitive Load Theory was used to redesign the content; online technologies were used to redesign the delivery. Student learning improved and the dropout rate was reduced. This article reports on both attitudinal and objective assessment: comparing…

Evaluation of a method of assessing faecal loading on plain abdominal radiographs in children

International Nuclear Information System (INIS)

Leech, S.C.; Sullivan, P.B.; McHugh, K.

1999-01-01

Background. Childhood constipation is common and assessment is often difficult. Plain abdominal radiography is simple and commonly used to assess constipation. The role of radiography with the use of a simple scoring system has not been fully evaluated. Objective. To assess the reliability of scoring faecal loading on plain abdominal radiographs in children with intractable constipation. Materials and methods. Plain abdominal radiographs from 33 constipated and 67 control children were independently assessed by three observers on two separate occasions. A scoring system was devised with scores from 0 (no stool) to 5 (gross faecal loading with bowel dilatation) in three areas of the colon, giving a total score of 0-15. Results. There were significant differences between the scores of the constipated and control radiographs for each observer (P = 0.05). There was no intra-observer variation (P = 0.12-0.69), but significant inter-observer variation was demonstrated (P = 0.00). Conclusions. We have found this scoring system to be a clinically useful and a reproducible tool in assessing childhood constipation. Assessment of faecal loading is subjective and varies between observers, although one observer will consistently score faecal loading on the same radiograph on successive occasions. To limit exposure to ionising radiation, we recommend that radiography be reserved for the investigation of intractable constipation, and its accuracy is improved if all radiographs are scored by the same observer. (orig.)

Superconducting magnetic energy storage (SMES). Results of a technology assessment

International Nuclear Information System (INIS)

Fleischer, T.; Juengst, K.P.; Brandl, V.; Maurer, W.; Nieke, E.

1995-05-01

The authors report on results of a Technology Assessment study commissioned by the German Federal Ministry of Education, Science, Research and Technology. The objective of this study was to evaluate the potential of superconducting magnetic energy storage (SMES) technology with respect to the economical, political and organization structures in the Federal Republic of Germany. The main focus of the study was on the technical and economic potential of large-scale SMES for diurnal load levelling applications. It was shown that there is no demand for the development of large SMES in Germany in the short and medium term. A second range of applications investigated is storage of electric energy for immediate delivery or consumption of electric power in case of need or for periodic power supply within the range of seconds. Due to its excellent dynamic properties SMES has substantial advantages over conventional storage technologies in this field. For those so-called dynamic applications SMES of small and medium energy capacity are needed. It was shown that SMES may be economically attractive for the provision of spinning reserve capacity in electrical networks, in particular cases for power quality applications (uninterruptable power supply, UPS) and for the compensation of cyclic loads, as well as in some market niches. The use of SMES for storage of recuperated energy in electrical railway traction systems has been proven to be uneconomical. Mobile SMES applications are unrealistic due to technical and size limitations. In SMES systems the energy is stored in a magnetic field. Biological objects as well as technical systems in the vicinity of a SMES plant are exposed to this field. The knowledge on impacts of magnetic fields on sensitive technical systems as well as on living organisms and especially on effects on human health is rather small and quite uncertain. (orig./MM) [de

Energy consumption assessment methods

Energy Technology Data Exchange (ETDEWEB)

Sutherland, K S

1975-01-01

The why, what, and how-to aspects of energy audits for industrial plants, and the application of energy accounting methods to a chemical plant in order to assess energy conservation possibilities are discussed. (LCL)

Residential Load Manageability Factor Analyses by Load Sensitivity Affected by Temperature

Directory of Open Access Journals (Sweden)

N. Eskandari

2016-12-01

Full Text Available Load side management is the basic and significant principle to keeping the balance between generation side and consumption side of electrical power energy. Load side management on typical medium voltage feeder is the power energy consumption control of connected loads with variation of essential parameters that loads do reaction to their variation. Knowing amount of load's reaction to each parameters variation in typical medium voltage feeder during the day, leads to gain Load Manageability Factor (LMF for that specific feeder that helps power utilities to manage their connected loads. Calculating this LMF needs to find out each types of load with unique inherent features behavior to each parameters variation. This paper results and future work results will help us to catch mentioned LMF. In this paper analysis of residential load behavior due to temperature variation with training artificial neural network will be done. Load behavior due to other essential parameters variations like energy pricing variation, major event happening, and power utility announcing to the customers, and etc will study in future works. Collecting all related works results in a unit mathematical equation or an artificial neural network will gain LMF.

Solar energy storage in German households: profitability, load changes and flexibility

International Nuclear Information System (INIS)

Kaschub, Thomas; Jochem, Patrick; Fichtner, Wolf

2016-01-01

The developments of battery storage technology together with photovoltaic (PV) roof-top systems might lead to far-reaching changes in the electricity demand structures and flexibility of households. The implications are supposed to affect the generation mix of utilities, distribution grid utilization, and electricity price. Using a techno-economic optimization model of a household system, we endogenously dimension PV system and stationary battery storage (SBS). The results of the reference scenario show positive net present values (NPV) for PV systems of approx. 500–1,800 EUR/kW_p and NPV for SBS of approx. 150–500 EUR/kWh. Main influences are the demand of the households, self-consumption rates, investment costs, and electricity prices. We integrate electric vehicles (EV) with different charging strategies and find increasing NPV of the PV system and self-consumption of approx. 70%. With further declining system prices for solar energy storage and increasing electricity prices, PV systems and SBS can be profitable in Germany from 2018 on even without a guaranteed feed-in tariff or subsidies. Grid utilization substantially changes by households with EV and PV-SBS. We discuss effects of different incentives and electricity tariff options (e. g. load limits or additional demand charges). Concluding, solar energy storage systems will bring substantial changes to electricity sales. - Highlights: • Domestic photovoltaics (PV) and storage systems are techno-economically analyzed. • PV & storage are profitable in the medium term due to high self-consumption rates. • Controlled electric vehicle charging improves load flexibility and self-generation. • External procurement of electricity drastically changes and decreases to 48–58%. • Dynamic tariffs e. g. with load limits or demand charges incentivize load shifting.

Power load leveling and energy saving measures for office buildings. Power load leveling and energy saving technology for the new building of the Kobe branch of the Kansai Electric Power Co., and its effect; Office biru no denryoku fuka heijunka sho energy hosaku. Kobe shiten shinshaoku ni okeru denryoku fuka heijunka sho energy gijutsu to sono koka

Energy Technology Data Exchange (ETDEWEB)

Tsuchiyama, M. [Kansai Electric Power Co. Inc., Osaka (Japan)

1999-06-10

This paper presents power load leveling and energy saving measures for heat source, air conditioning and lighting of the new Kobe branch building. The low-temperature hot-air system adopts an ice storage system, and reduces blowing power by 12 degreesC blowing in place of normal 16 degreesC blowing, and an initial cost by duct size reduction. The continuous air conditioning system levels an initial peak load of air conditioning as compared with normal air conditioning only for working hours for buildings with large heat capacity. In addition, as power load leveling measures for the whole building, the complete heat storage system using an underground internal melting type ice storage tank is adopted. Energy saving for lighting is achieved with a dimming lighting controlling its lighting output by inverter. The following effects are expected by these new technologies: Load leveling effect of 30%, energy saving effect of 20.2% and CO{sub 2} reduction effect of 24.1%. (NEDO)

Loading nature of the interfacial cracks in a joint component under fusion-relevant thermal loads

International Nuclear Information System (INIS)

You, J.H.

1998-01-01

One of the standard design concepts for divertor components in a fusion reactor is the bonded joint structure. Understanding the loading nature of interfacial cracks are significant for the assessment of structural integrity of divertor joint components. In this paper, the thermomechanical loading nature of interfacial cracks is discussed. A bi-material joint element consisting of the CFC/TZM system is considered. A typical fusion operation condition is simulated assuming a pulsed high heat flux loading. Stress singularities near the interfacial crack tips are characterized quantitatively in terms of the fracture mechanical parameters. The evolution of the stress intensity factors and the energy release rate during the given transient thermal load are determined. The difference in loading characteristics between the edge crack and the center crack is discussed. High heat flux cycling tests are performed on brazed CFC/TZM divertor elements in an electron beam test facility. The microstructures of the damaged interface agree with the predicted fracture modes. The loading nature and possible failure mechanisms are discussed for a fusion-relevant thermal loading. (orig.)

Tapping the energy storage potential in electric loads to deliver load following and regulation, with application to wind energy

International Nuclear Information System (INIS)

Callaway, Duncan S.

2009-01-01

This paper develops new methods to model and control the aggregated power demand from a population of thermostatically controlled loads, with the goal of delivering services such as regulation and load following. Previous work on direct load control focuses primarily on peak load shaving by directly interrupting power to loads. In contrast, the emphasis of this paper is on controlling loads to produce relatively short time scale responses (hourly to sub-hourly), and the control signal is applied by manipulation of temperature set points, possibly via programmable communicating thermostats or advanced metering infrastructure. To this end, the methods developed here leverage the existence of system diversity and use physically-based load models to inform the development of a new theoretical model that accurately predicts - even when the system is not in equilibrium - changes in load resulting from changes in thermostat temperature set points. Insight into the transient dynamics that result from set point changes is developed by deriving a new exact solution to a well-known hybrid state aggregated load model. The eigenvalues of the solution, which depend only on the thermal time constant of the loads under control, are shown to have a strong effect on the accuracy of the model. The paper also shows that load heterogeneity - generally something that must be assumed away in direct load control models - actually has a positive effect on model accuracy. System identification techniques are brought to bear on the problem, and it is shown that identified models perform only marginally better than the theoretical model. The paper concludes by deriving a minimum variance control law, and demonstrates its effectiveness in simulations wherein a population of loads is made to follow the output of a wind plant with very small changes in the nominal thermostat temperature set points.

Determination of the wind power systems load to achieve operation in the maximum energy area

Science.gov (United States)

Chioncel, C. P.; Tirian, G. O.; Spunei, E.; Gillich, N.

2018-01-01

This paper analyses the operation of the wind turbine, WT, in the maximum power point, MPP, by linking the load of the Permanent Magnet Synchronous Generator, PMSG, with the wind speed value. The load control methods at wind power systems aiming an optimum performance in terms of energy are based on the fact that the energy captured by the wind turbine significantly depends on the mechanical angular speed of the wind turbine. The presented control method consists in determining the optimal mechanical angular speed, ωOPTIM, using an auxiliary low power wind turbine, WTAUX, operating without load, at maximum angular velocity, ωMAX. The method relies on the fact that the ratio ωOPTIM/ωMAX has a constant value for a given wind turbine and does not depend on the time variation of the wind speed values.

Balancing Power Absorption and Fatigue Loads in Irregular Waves for an Oscillating Surge Wave Energy Converter: Preprint

Energy Technology Data Exchange (ETDEWEB)

Tom, Nathan M.; Yu, Yi-Hsiang; Wright, Alan D.; Lawson, Michael

2016-06-01

The aim of this paper is to describe how to control the power-to-load ratio of a novel wave energy converter (WEC) in irregular waves. The novel WEC that is being developed at the National Renewable Energy Laboratory combines an oscillating surge wave energy converter (OSWEC) with control surfaces as part of the structure; however, this work only considers one fixed geometric configuration. This work extends the optimal control problem so as to not solely maximize the time-averaged power, but to also consider the power-take-off (PTO) torque and foundation forces that arise because of WEC motion. The objective function of the controller will include competing terms that force the controller to balance power capture with structural loading. Separate penalty weights were placed on the surge-foundation force and PTO torque magnitude, which allows the controller to be tuned to emphasize either power absorption or load shedding. Results of this study found that, with proper selection of penalty weights, gains in time-averaged power would exceed the gains in structural loading while minimizing the reactive power requirement.

Data from renewable energy assessments for resort islands in the South China Sea

Science.gov (United States)

Basir Khan, M. Reyasudin; Jidin, Razali; Pasupuleti, Jagadeesh

2015-01-01

Renewable energy assessments for resort islands in the South China Sea were conducted that involves the collection and analysis of meteorological and topographic data. The meteorological data was used to assess the PV, wind and hydropower system potentials on the islands. Furthermore, the reconnaissance study for hydro-potentials were conducted through topographic maps in order to determine the potential sites suitable for development of run-of-river hydropower generation. The stream data was collected for 14 islands in the South China Sea with a total of 51 investigated sites. The data from this study are related to the research article “Optimal combination of solar, wind, micro-hydro and diesel systems based on actual seasonal load profiles for a resort island in the South China Sea” published in Energy (Khan et al., 2015) [1]. PMID:26779562

Assessing the benefits of residential demand response in a real time distribution energy market

International Nuclear Information System (INIS)

Siano, Pierluigi; Sarno, Debora

2016-01-01

Highlights: • A new probabilistic methodology, integrating DR in a distribution energy market is proposed. • The method can alleviate distribution network congestions. • This method based on D-LMPs allows cost savings for end-user customers. • Innovative thermal and shiftable loads Real Time control algorithms are also presented. - Abstract: In the field of electricity distribution networks and with the advent of smart grids and microgrids, the use of Distribution Locational Marginal Price (D-LMPs) in a Real Time (RT) distribution market managed by a Distribution System Operator (DSO) is discussed in presence of empowered residential end-users that are able to bid for energy by a demand aggregator while following Demand Response (DR) initiatives. Each customer is provided by a transactive controller, which reads the locational market signals and answers with a bid taking into account the user preferences about some appliances involved in DR activities and controlled by smart plugs-in. In particular, Heating Ventilation and Air Conditioning (HVAC) appliances and shiftable loads are controlled so that their consumption profile can be modified according to the price of energy. In order to assess the effectiveness of the proposed method in terms of energy and cost saving, an innovative probabilistic methodology for evaluating the impact of residential DR choices considering uncertainties related to load demand, user preferences, environmental conditions, house thermal behavior and wholesale market trends has been proposed. The uncertainties related to the stochastic variations of the variables involved are modeled by using the Monte Carlo Simulation (MCS) method. The combination of MCS and RT distribution market simulation based on D-LMPs are used to assess the operation and impact of the DR method over one month. Simulations results on an 84-buses distribution network confirmed that the proposed method allows saving costs for residential end-users and making

Elastic-plastic Fracture Mechanics Assessment of nozzle corners submitted to thermal shock loading

International Nuclear Information System (INIS)

Chapuliot, S.; Marie, S.

2016-01-01

This paper focuses on the development of a simplified analytical scheme for the elastic-plastic Fracture Mechanics Assessment of large nozzle corners. Within that frame, following the specific numerical effort performed for the definition of a Stress Intensity Factor compendium, complementary elastic-plastic developments are proposed here for the consideration of the thermal shock loading in the elastic-plastic domain: this type of loading is a major loading for massive structures such as nozzle corners of large components. Thus, an important numerical was performed in order to extend the applicability domain of existing analytical schemes to those complex geometries. The final formulation is a simple one, applicable to a large variety of materials and geometrical configurations as long as the structure is large and the defect remains small in comparison to the internal radius of the nozzle. - Highlights: • Fracture Mechanics Assessment of large nozzle corners. • Elastic-plastic Stress Intensity Factor determination under thermal shock loading. • Semi-analytical schemes for J calculation.

Using the NASA Task Load Index to Assess Workload in Electronic Medical Records.

Science.gov (United States)

Hudson, Darren; Kushniruk, Andre W; Borycki, Elizabeth M

2015-01-01

Electronic medical records (EMRs) has been expected to decrease health professional workload. The NASA Task Load Index has become an important tool for assessing workload in many domains. However, its application in assessing the impact of an EMR on nurse's workload has remained to be explored. In this paper we report the results of a study of workload and we explore the utility of applying the NASA Task Load Index to assess impact of an EMR at the end of its lifecycle on nurses' workload. It was found that mental and temporal demands were the most responsible for the workload. Further work along these lines is recommended.

Assessment of Industrial Load for Demand Response across Western Interconnect

Energy Technology Data Exchange (ETDEWEB)

Alkadi, Nasr E [ORNL; Starke, Michael R [ORNL; Ma, Ookie [United States Department of Energy (DOE), Office of Efficiency and Renewable Energy (EERE)

2013-11-01

Demand response (DR) has the ability to both increase power grid reliability and potentially reduce operating system costs. Understanding the role of demand response in grid modeling has been difficult due to complex nature of the load characteristics compared to the modeled generation and the variation in load types. This is particularly true of industrial loads, where hundreds of different industries exist with varying availability for demand response. We present a framework considering industrial loads for the development of availability profiles that can provide more regional understanding and can be inserted into analysis software for further study. The developed framework utilizes a number of different informational resources, algorithms, and real-world measurements to perform a bottom-up approach in the development of a new database with representation of the potential demand response resource in the industrial sector across the U.S. This tool houses statistical values of energy and demand response (DR) potential by industrial plant and geospatially locates the information for aggregation for different territories without proprietary information. This report will discuss this framework and the analyzed quantities of demand response for Western Interconnect (WI) in support of evaluation of the cost production modeling with power grid modeling efforts of demand response.

Wind Energy Management System EMS Integration Project: Incorporating Wind Generation and Load Forecast Uncertainties into Power Grid Operations

Energy Technology Data Exchange (ETDEWEB)

Makarov, Yuri V.; Huang, Zhenyu; Etingov, Pavel V.; Ma, Jian; Guttromson, Ross T.; Subbarao, Krishnappa; Chakrabarti, Bhujanga B.

2010-01-01

unique features make this work a significant step forward toward the objective of incorporating of wind, solar, load, and other uncertainties into power system operations. Currently, uncertainties associated with wind and load forecasts, as well as uncertainties associated with random generator outages and unexpected disconnection of supply lines, are not taken into account in power grid operation. Thus, operators have little means to weigh the likelihood and magnitude of upcoming events of power imbalance. In this project, funded by the U.S. Department of Energy (DOE), a framework has been developed for incorporating uncertainties associated with wind and load forecast errors, unpredicted ramps, and forced generation disconnections into the energy management system (EMS) as well as generation dispatch and commitment applications. A new approach to evaluate the uncertainty ranges for the required generation performance envelope including balancing capacity, ramping capability, and ramp duration has been proposed. The approach includes three stages: forecast and actual data acquisition, statistical analysis of retrospective information, and prediction of future grid balancing requirements for specified time horizons and confidence levels. Assessment of the capacity and ramping requirements is performed using a specially developed probabilistic algorithm based on a histogram analysis, incorporating all sources of uncertainties of both continuous (wind and load forecast errors) and discrete (forced generator outages and start-up failures) nature. A new method called the “flying brick” technique has been developed to evaluate the look-ahead required generation performance envelope for the worst case scenario within a user-specified confidence level. A self-validation algorithm has been developed to validate the accuracy of the confidence intervals.

Frictional systems under periodic loads — History-dependence, non-uniqueness and energy dissipation

International Nuclear Information System (INIS)

Barber, J R

2012-01-01

Nominally static contacts such as bolted or shrink-fit joints typically experience regions of microslip when subjected to oscillatory loading. This results in energy dissipation, reflected as apparent hysteretic damping of the system, and also may cause the initiation of fretting fatigue cracks. Early theoretical studies of the Hertzian contact problem by Cattaneo and Mindlin were confirmed experimentally by Johnson, who identified signs of fretting damage in the slip annulus predicted by the theory. For many years, tribologists assumed that Melan's theorem in plasticity could be extended to frictional systems — i.e. that if there exists a state of residual stress associated with frictional slip that is sufficient to prevent periodic slip in the steady state, then the system will shake down, regardless of the initial condition. However, we now know that this is true only if there is no coupling between the normal and tangential loading problems, as will be the case notably when contact occurs on a symmetry plane. For all other cases, periodic loading scenarios can be devised such that shakedown occurs for some initial conditions and not for others. The initial condition here might be determined by the assembly protocol — e.g. the order in which a set of bolts is tightened — or by the exact loading path before the steady cycle is attained. This non-uniqueness of the steady state persists at load amplitudes above the shakedown limit, in which case there is always some dissipation, but the dissipation per cycle (and hence both the effective damping and the susceptibility to fretting damage) depends on the initial conditions. This implies that fretting fatigue experiments need to follow a well-defined assembly protocol if reproducible results are to be obtained. We shall also present results showing that when both normal and tangential forces vary in time, the energy dissipation is very sensitive to the relative phase of the oscillatory components, being greatest

Thermodynamic analysis of load-leveling hyper energy converting and utilization system

International Nuclear Information System (INIS)

Kiani, Behdad; Akisawa, Atsushi; Kashiwagi, Takao

2008-01-01

Load-leveling hyper energy converting and utilization system (LHECUS) is a hybrid cycle which utilizes ammonia-water mixture as the working fluid in a combined power generation and refrigeration cycle. The power generation cycle functions as a Kalina cycle and an absorption refrigeration cycle is combined with it as a bottoming cycle. LHECUS is designed to utilize the waste heat from industry to produce cooling and power simultaneously. The refrigeration effect can be either transported to end-use sectors by means of a solution transportation absorption chiller (STA) as solution concentration difference or stored for demand load leveling. This paper shows a simulation of the LHECUS cycle. A computer model was written to balance the cycle and key parameters for optimizing the cycle were identified

Assessment of the impact of frequency support on DFIG wind turbine loads

DEFF Research Database (Denmark)

Barahona Garzón, Braulio; You, Rui; Hansen, Anca Daniela

2013-01-01

This study presents models and tools for the assessment of the impact that providing frequency support has on doubly-fed generator (DFIG) wind turbine structural loads and drive train. The focus is on primary frequency support, aiming at quantifying the impact on wind turbines acting as frequency...... code and electrical models. In this simulation framework, the impact that power system conditions can have on wind turbines, and vice versa the support that wind turbines can offer to the power system can be investigated....... containment reserve and providing inertial response. The sensitivity of wind turbine load indicators—load duration- distribution and maximum load values—to inertial response control actions and different torsional models of drive train is investigated. The analysis is done by co-simulations of an aeroelastic...

Fat or lean: adjustment of endogenous energy stores to predictable and unpredictable changes in allostatic load

Science.gov (United States)

Schultner, Jannik; Kitaysky, Alexander S.; Welcker, Jorg; Hatch, Scott

2013-01-01

1. The ability to store energy endogenously is an important ecological mechanism that allows animals to buffer predictable and unpredictable variation in allostatic load. The secretion of glucocorticoids, which reflects changes in allostatic load, is suggested to play a major role in the adjustment of endogenous stores to these varying conditions.

Sizing community energy storage systems to reduce transformer overloading with emphasis on plug-in electric vehicle loads

Science.gov (United States)

Trowler, Derik Wesley

The research objective of this study was to develop a sizing method for community energy storage systems with emphasis on preventing distribution transformer overloading due to plug-in electric vehicle charging. The method as developed showed the formulation of a diversified load profile based upon residential load data for several customers on the American Electric Power system. Once a load profile was obtained, plug-in electric vehicle charging scenarios which were based upon expected adoption and charging trends were superimposed on the load profile to show situations where transformers (in particular 25 kVA, 50 kVA, and 100 kVA) would be overloaded during peak hours. Once the total load profiles were derived, the energy and power requirements of community energy storage systems were calculated for a number of scenarios with different combinations of numbers of homes and plug-in electric vehicles. The results were recorded and illustrated into charts so that one could determine the minimum size per application. Other topics that were covered in this thesis were the state of the art and future trends in plug-in electric vehicle and battery chemistry adoption and development. The goal of the literature review was to confirm the already suspected notion that Li-ion batteries are best suited and soon to be most cost-effective solution for applications requiring small, efficient, reliable, and light-weight battery systems such as plug-in electric vehicles and community energy storage systems. This thesis also includes a chapter showing system modeling in MATLAB/SimulinkRTM. All in all, this thesis covers a wide variety of considerations involved in the designing and deploying of community energy storage systems intended to mitigate the effects of distribution transformer overloading.

Analytic model for ultrasound energy receivers and their optimal electric loads II: Experimental validation

Science.gov (United States)

Gorostiaga, M.; Wapler, M. C.; Wallrabe, U.

2017-10-01

In this paper, we verify the two optimal electric load concepts based on the zero reflection condition and on the power maximization approach for ultrasound energy receivers. We test a high loss 1-3 composite transducer, and find that the measurements agree very well with the predictions of the analytic model for plate transducers that we have developed previously. Additionally, we also confirm that the power maximization and zero reflection loads are very different when the losses in the receiver are high. Finally, we compare the optimal load predictions by the KLM and the analytic models with frequency dependent attenuation to evaluate the influence of the viscosity.

Using Airborne LIDAR Data for Assessment of Forest Fire Fuel Load Potential

Science.gov (United States)

İnan, M.; Bilici, E.; Akay, A. E.

2017-11-01

Forest fire incidences are one of the most detrimental disasters that may cause long terms effects on forest ecosystems in many parts of the world. In order to minimize environmental damages of fires on forest ecosystems, the forested areas with high fire risk should be determined so that necessary precaution measurements can be implemented in those areas. Assessment of forest fire fuel load can be used to estimate forest fire risk. In order to estimate fuel load capacity, forestry parameters such as number of trees, tree height, tree diameter, crown diameter, and tree volume should be accurately measured. In recent years, with the advancements in remote sensing technology, it is possible to use airborne LIDAR for data estimation of forestry parameters. In this study, the capabilities of using LIDAR based point cloud data for assessment of the forest fuel load potential was investigated. The research area was chosen in the Istanbul Bentler series of Bahceköy Forest Enterprise Directorate that composed of mixed deciduous forest structure.

Load profiles analysis for electricity market

Directory of Open Access Journals (Sweden)

Radu Porumb

2014-04-01

Full Text Available In the wake of electric power system transition towards smart grids, and the adoption of the electric market schemes, electric utilities are facing the need of a better load profiles understanding for their customers. In this work, some key objectives were addresses, such as definition of the mathematical model for calculating the hourly energy specific, identification of the three target groups for users who have developed consumer profiles, definition of the two types of significant load and assessment of the impact of using consumer profiles on users.

Risk Assessment of Heating, Ventilating, and Air-Conditioning Strategies in Low-Load Homes

Energy Technology Data Exchange (ETDEWEB)

Poerschke, Andrew [IBACOS, Inc., Pittsburgh, PA (United States)

2016-02-17

"Modern, energy efficient homes conforming to the Zero Energy Ready Home standard face the challenge of meeting high customer expectations for comfort. Traditional heating, ventilation, and air conditioning (HVAC) sizing and control strategies may be insufficient to adequately condition each zone due to unique load patterns in each room caused by a number of factors. These factors include solar heat gains, occupant-related gains, and gains associated with appliances and electronics. Because of shrinking shell loads, these intermittent factors are having an increasingly significant impact on the thermal load in each zone. Consequently, occupant comfort can be compromised. To evaluate the impact of climate and house geometry, as well as HVAC system and control strategies on comfort conditions, IBACOS analyzed the results of 99 TRNSYS multiple-zone simulations. The results of this analysis indicate that for simple-geometry and single-story plans, a single zone and thermostat can adequately condition the entire house. Demanding house geometry and houses with multiple stories require the consideration of multiple thermostats and multiple zones.

Performance assessment of a power loaded supercapacitor based on manufacturer data

International Nuclear Information System (INIS)

Mellincovsky, Martin; Kuperman, Alon; Lerman, Chaim; Aharon, Ilan; Reichbach, Noam; Geula, Gal; Nakash, Ronen

2013-01-01

Highlights: • Analytic performance of a power loaded supercapacitor is derived. • Power and energy capabilities based on manufacturer data are obtained. • Power limitations based on depth of discharge are presented. - Abstract: Analytical derivation of constant power loaded supercapacitor behavior is presented in the paper. Simple RC model based on manufacturer datasheet extracted parameters is employed. Power and energy related figures of merit are obtained from the derived expressions and compared to the datasheet provided values. It is revealed that some of the performance characteristics provided in most of the datasheets are theoretical and cannot be achieved in practice. The process of a realistic Ragone plot derivation based on the proposed method is described in the paper as well. It is shown that the lower limit of supercapacitor voltage imposes certain limits on power and energy capabilities of the device. Extended simulation and experimental results are provided in order to reinforce the proposed method and justify the selected RC model for describing the supercapacitor performance. By appropriate comparison of simulations and experiments it is proven that the selected model, while being oversimplified and low order, may be used to predict supercapacitor behavior with reasonable accuracy to perform at least an initial design

1-GWh diurnal load-leveling superconducting magnetic energy storage system reference design. Appendix A: energy storage coil and superconductor

International Nuclear Information System (INIS)

Schermer, R.I.

1979-09-01

The technical aspects of a 1-GWh Superconducting Magnetic Energy Storage (SMES) coil for use as a diurnal load-leveling device in an electric utility system are presented. The superconductor for the coil is analyzed, and costs for the entire coil are developed

Environmental assessment of energy production from waste and biomass

Energy Technology Data Exchange (ETDEWEB)

Tonini, D.

2013-02-15

robust energy and environmental performances. Innovative waste refineries may achieve similar performances from a GHG perspective and, in addition, may recover nutrients. In the perspective of future energy systems with increased shares of fluctuating energy sources (e.g. wind energy) the flexibility of the energy conversion process should also be considered in the environmental assessment. The storability of the produced energy carrier along with the regulation ability and the capacity of switching among outputs may offer substantial benefits to the surrounding energy system. In this perspective, waste refineries producing storable biogas and solid fuel may offer increased flexibility compared with base load incinerators. (Author)

Plug Load Behavioral Change Demonstration Project

Energy Technology Data Exchange (ETDEWEB)

Metzger, I.; Kandt, A.; VanGeet, O.

2011-08-01

This report documents the methods and results of a plug load study of the Environmental Protection Agency's Region 8 Headquarters in Denver, Colorado, conducted by the National Renewable Energy Laboratory. The study quantified the effect of mechanical and behavioral change approaches on plug load energy reduction and identified effective ways to reduce plug load energy. Load reduction approaches included automated energy management systems and behavioral change strategies.

RF Loads for Energy Recovery

CERN Document Server

Federmann, S; Caspers, F

2012-01-01

Different conceptional designs for RF high power loads are presented. One concept implies the use of solid state rectifier modules for direct RF to DC conversion with efficiencies beyond 80%. In addition, robust metallic low-Q resonant structures, capable of operating at high temperatures (>150 ◦C) are discussed. Another design deals with a very high temperature (up to 800 ◦C) air cooled load using a ceramic foam block inside a metal enclosure. This porous ceramic block is the microwave absorber and is not brazed to the metallic enclosure.

The impact of hybrid energy storage on power quality, when high power pulsed DC loads are operated on a microgrid testbed

Science.gov (United States)

Kelley, Jay Paul

As the Navy's demands for high power transient loads evolves, so too does the need for alternative energy sources to back-up the more traditional power generation. Such applications in need of support include electrical grid backup and directed energy weapon systems such as electromagnetic launchers, laser systems, and high power microwave generators, among others. Among the alternative generation sources receiving considerable attention are energy storage devices such as rechargeable electrochemical batteries and capacitors. In such applications as those mentioned above, these energy storage devices offer the ability to serve a dual role as both a power source to the various loads as well high power loads themselves to the continual generation when the high power transient loads are in periods of downtime. With the recent developments in electrochemical energy storage, lithium-ion batteries (LIBs) seem like the obvious choice, but previous research has shown that the elevated rates of charging can be detrimental to both the cycle life and the operational life span of the device. In order to preserve the batteries, their charge rate must be limited. One proposed method to accomplish the dual role task mentioned above, while preserving the life of the batteries, is by combining high energy density LIBs with high power density electric double layer capacitors (EDLCs) or lithium-ion capacitors (LICs) using controllable power electronics to adjust the flow of power to and from each device. Such a configuration is typically referred to as hybrid energy storage module (HESM). While shipboard generators start up, the combined high energy density and high power density of the HESM provides the capability to source critical loads for an extended period of time at the high rates they demand. Once the generator is operationally efficient, the HESM can act as a high energy reservoir to harvest the energy from the generator while the loads are in short periods of inactivity

Assessment of Wind Parameter Sensitivity on Extreme and Fatigue Wind Turbine Loads

Energy Technology Data Exchange (ETDEWEB)

Robertson, Amy N [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Sethuraman, Latha [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Jonkman, Jason [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Quick, Julian [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2018-01-12

Wind turbines are designed using a set of simulations to ascertain the structural loads that the turbine could encounter. While mean hub-height wind speed is considered to vary, other wind parameters such as turbulence spectra, sheer, veer, spatial coherence, and component correlation are fixed or conditional values that, in reality, could have different characteristics at different sites and have a significant effect on the resulting loads. This paper therefore seeks to assess the sensitivity of different wind parameters on the resulting ultimate and fatigue loads on the turbine during normal operational conditions. Eighteen different wind parameters are screened using an Elementary Effects approach with radial points. As expected, the results show a high sensitivity of the loads to the turbulence standard deviation in the primary wind direction, but the sensitivity to wind shear is often much greater. To a lesser extent, other wind parameters that drive loads include the coherence in the primary wind direction and veer.

Adequacy assessment of composite generation and transmission systems incorporating wind energy conversion systems

Science.gov (United States)

Gao, Yi

The development and utilization of wind energy for satisfying electrical demand has received considerable attention in recent years due to its tremendous environmental, social and economic benefits, together with public support and government incentives. Electric power generation from wind energy behaves quite differently from that of conventional sources. The fundamentally different operating characteristics of wind energy facilities therefore affect power system reliability in a different manner than those of conventional systems. The reliability impact of such a highly variable energy source is an important aspect that must be assessed when the wind power penetration is significant. The focus of the research described in this thesis is on the utilization of state sampling Monte Carlo simulation in wind integrated bulk electric system reliability analysis and the application of these concepts in system planning and decision making. Load forecast uncertainty is an important factor in long range planning and system development. This thesis describes two approximate approaches developed to reduce the number of steps in a load duration curve which includes load forecast uncertainty, and to provide reasonably accurate generating and bulk system reliability index predictions. The developed approaches are illustrated by application to two composite test systems. A method of generating correlated random numbers with uniform distributions and a specified correlation coefficient in the state sampling method is proposed and used to conduct adequacy assessment in generating systems and in bulk electric systems containing correlated wind farms in this thesis. The studies described show that it is possible to use the state sampling Monte Carlo simulation technique to quantitatively assess the reliability implications associated with adding wind power to a composite generation and transmission system including the effects of multiple correlated wind sites. This is an important

Energy Coordinative Optimization of Wind-Storage-Load Microgrids Based on Short-Term Prediction

Directory of Open Access Journals (Sweden)

Changbin Hu

2015-02-01

Full Text Available According to the topological structure of wind-storage-load complementation microgrids, this paper proposes a method for energy coordinative optimization which focuses on improvement of the economic benefits of microgrids in the prediction framework. First of all, the external characteristic mathematical model of distributed generation (DG units including wind turbines and storage batteries are established according to the requirements of the actual constraints. Meanwhile, using the minimum consumption costs from the external grid as the objective function, a grey prediction model with residual modification is introduced to output the predictive wind turbine power and load at specific periods. Second, based on the basic framework of receding horizon optimization, an intelligent genetic algorithm (GA is applied to figure out the optimum solution in the predictive horizon for the complex non-linear coordination control model of microgrids. The optimum results of the GA are compared with the receding solution of mixed integer linear programming (MILP. The obtained results show that the method is a viable approach for energy coordinative optimization of microgrid systems for energy flow and reasonable schedule. The effectiveness and feasibility of the proposed method is verified by examples.

Status of load management

Energy Technology Data Exchange (ETDEWEB)

Juchymenko, A

1983-08-01

A summary is presented of the status of load management, defined as any activity by an electric utility to affect the size and characteristics of its load. Load management is currently viewed by electric utilities as an important tool for marketing electricity in a competitive fuel situation. A major aim of the National Energy Program is to reduce Canada's dependence on oil by 1990 to 10% of the energy used by all markets. As a result, electricity may play a greater role in the supply of primary energy. Research in load management has been directed mostly towards the residential market, especially direct control of domestic hot water heaters and air conditioners. Studies conducted in Canada and the U.S. to determine user's receptiveness to direct control of loads and thermal energy storage systems indicate that these load management techniques are in most cases not acceptable to customers, who prefer voluntary reduction in demand. The potential exists in the industrial market to use load management to assist in electrifying many of the fossil fuel-fired processes at competitive energy prices. Some of the more important applications include an industrial heat pump to heat liquids to 120{degree}C, induction heating for melting and heat treating of metals, and mechanical vapor recompression equipment to produce proces steam. 21 refs., 2 figs., 2 tabs.

Modelling and analysis of a novel compressed air energy storage system for trigeneration based on electrical energy peak load shifting

International Nuclear Information System (INIS)

Lv, Song; He, Wei; Zhang, Aifeng; Li, Guiqiang; Luo, Bingqing; Liu, Xianghua

2017-01-01

Highlights: • A new CAES system for trigeneration based on electrical peak load shifting is proposed. • The theoretical models and the thermodynamics process are established and analyzed. • The relevant parameters influencing its performance have been discussed and optimized. • A novel energy and economic evaluation methods is proposed to evaluate the performance of the system. - Abstract: The compressed air energy storage (CAES) has made great contribution to both electricity and renewable energy. In the pursuit of reduced energy consumption and relieving power utility pressure effectively, a novel trigeneration system based on CAES for cooling, heating and electricity generation by electrical energy peak load shifting is proposed in this paper. The cooling power is generated by the direct expansion of compressed air, and the heating power is recovered in the process of compression and storage. Based on the working principle of the typical CAES, the theoretical analysis of the thermodynamic system models are established and the characteristics of the system are analyzed. A novel method used to evaluate energy and economic performance is proposed. A case study is conducted, and the economic-social and technical feasibility of the proposed system are discussed. The results show that the trigeneration system works efficiently at relatively low pressure, and the efficiency is expected to reach about 76.3% when air is compressed and released by 15 bar. The annual monetary cost saving annually is about 53.9%. Moreover, general considerations about the proposed system are also presented.

The energy assessment

International Nuclear Information System (INIS)

Ramain, Patrice

2015-10-01

The energy assessment is obtained by determining the quantities of energy produced, transformed and consumed during a year for a country or a set of countries. The author presents this specific accounting and, while providing the associated tables, first indicates that, according to different international bodies (OECD and IAE, EUROSTAT, or UNO), different energetic products are taken into account to elaborate this assessment, as well for operations related to energy supply, energetic product transformation, and final consumption. He also evokes some key indicators which can be used to draw a more precise or specific energetic portray of a country. Then, he addresses the issue of a common measurement unit: a monetary unit is impossible to use due to price variations, physical units (tons of carbon equivalent, tons of oil equivalent, BtU) are not adequate when talking about hydraulic electricity or geothermal heat. Thus, the author evokes the possible use of exergy or of calorific power, this last one with different methods (energetic content, partial substitution)

TUF assessment of an abnormal load rejection event at Darlington NGS

International Nuclear Information System (INIS)

Liauw, W.K.; Liu, W.S.

1997-01-01

The main purpose of reactor system code development is to support plant operation and to assist in safety analysis. To illustrate the operational support activities of the TUF code, the assessment of a simple case of abnormal load rejection event at Darlington NGS is described. The main assessment of this event examines the flow conditions at the steam generators and the possible impact on the turbine. This assessment demonstrates the TUF capability in the operational support analysis for CANDU reactors. (author)

Impaired brain energy gain upon a glucose load in obesity.

Science.gov (United States)

Wardzinski, Ewelina K; Kistenmacher, Alina; Melchert, Uwe H; Jauch-Chara, Kamila; Oltmanns, Kerstin M

2018-03-06

There is evidence that the brain's energy status is lowered in obesity despite of chronic hypercaloric nutrition. The underlying mechanisms are unknown. We hypothesized that the brain of obese people does not appropriately generate energy in response to a hypercaloric supply. Glucose was intravenously infused in 17 normal weights and 13 obese participants until blood glucose concentrations reached the postprandial levels of 7 mmol/L and 10 mmol/L. Changes in cerebral adenosine triphosphate (ATP) and phosphocreatine (PCr) content were measured by 31 phosphorus magnetic resonance spectroscopy and stress hormonal measures regulating glucose homeostasis were monitored. Because vitamin C is crucial for a proper neuronal energy synthesis we determined circulating concentrations during the experimental testing. Cerebral high-energy phosphates were increased at blood glucose levels of 7 mmol/L in normal weights, which was completely missing in the obese. Brain energy content moderately raised only at blood glucose levels of 10 mmol/L in obese participants. Vitamin C concentrations generally correlated with the brain energy content at blood glucose concentrations of 7 mmol/L. Our data demonstrate an inefficient cerebral energy gain upon a glucose load in obese men, which may result from a dysfunctional glucose transport across the blood-brain barrier or a downregulated energy synthesis in mitochondrial oxidation processes. Our finding offers an explanation for the chronic neuroenergetic deficiency and respectively missing satiety perception in obesity. Copyright © 2018. Published by Elsevier Inc.

The Effects of Surface Waves and Submergence on the Performance and Loading of a Tidal Turbine

OpenAIRE

Guo, Xiaoxian; Gao, Zhen; Yang, Jianmin; Moan, Torgeir; Lu, Haining; Li, Xin; Lu, Wenyue

2017-01-01

Tidal energy has the advantages of high predictability, high energy density, and limited environmental impacts. As tidal turbines are expected to be used in the most energetic waters where there might be significant waves, the assessment of unsteady hydrodynamic load due to surface waves is of great concern. The objective of this paper is to assess the effects of surface waves and submergence of the turbine on the power performance and loads of a tidal turbine by experimental approach. The ex...

Study on loading coefficient in steam explosion process of corn stalk.

Science.gov (United States)

Sui, Wenjie; Chen, Hongzhang

2015-03-01

The object of this work was to evaluate the effect of loading coefficient on steam explosion process and efficacy of corn stalk. Loading coefficient's relation with loading pattern and material property was first revealed, then its effect on transfer process and pretreatment efficacy of steam explosion was assessed by established models and enzymatic hydrolysis tests, respectively, in order to propose its optimization strategy for improving the process economy. Results showed that loading coefficient was mainly determined by loading pattern, moisture content and chip size. Both compact loading pattern and low moisture content improved the energy efficiency of steam explosion pretreatment and overall sugar yield of pretreated materials, indicating that they are desirable to improve the process economy. Pretreatment of small chip size showed opposite effects in pretreatment energy efficiency and enzymatic hydrolysis performance, thus its optimization should be balanced in investigated aspects according to further techno-economical evaluation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Blinded comparison of faecal loading on plain radiography versus radio-opaque marker transit studies in the assessment of constipation

Energy Technology Data Exchange (ETDEWEB)

Cowlam, S. [Sunderland Royal Hospital, Sunderland (United Kingdom); Vinayagam, R.; Khan, U.; Marsden, S.; Minty, I.; Moncur, P.; Bain, I. [University Hospital of North Durham, Durham (United Kingdom); Yiannakou, Y.J. [University Hospital of North Durham, Durham (United Kingdom)], E-mail: yan.yiannakou@cddft.nhs.uk

2008-12-15

Aim: To compare faecal loading on plain radiography versus radio-opaque marker transit studies in the assessment of constipation. Methods: The study group was a convenience sample of patients attending the Durham Constipation Clinic. All patients underwent transit studies according to an established protocol, and severity of constipation was assessed contemporaneously using a validated questionnaire (PAC-SYM). Transit studies were performed using radio-opaque markers that were ingested over 3 consecutive days, with a radiograph taken on the fourth day. Digital images of the radiograph were digitally altered to remove all traces of the transit markers without affecting the underlying pattern of faecal loading. Four observers assessed faecal loading independently; two clinicians (C1 and C2) and two radiologists (R1 and R2). C1 and R1 used a previously described formal scoring method of assessing faecal loading, whereas C2 and R2 assessed the images as if they were in a clinic or reporting session, grading the faecal loading as mild, moderate, or severe. Results: One hundred patients were recruited out of 186 presenting in a 2-year period. All patients completed assessments. The correlation between observers was only fair to moderate (r ranging from 0.34-0.51). There were some surprisingly marked disagreements in 10-18% of assessments. The correlation between faecal loading and transit was weak for all observers (r ranging from 0.261-0.311). Symptom severity did not correlate with faecal loading. Conclusion: These results suggest that there is considerable inter-observer variation in the radiological assessment of faecal loading, irrespective of the training or method used by the observer, and that there is very poor correlation with colonic transit. The diagnosis of constipation, and the assessment of severity, is best performed clinically.

Blinded comparison of faecal loading on plain radiography versus radio-opaque marker transit studies in the assessment of constipation

International Nuclear Information System (INIS)

Cowlam, S.; Vinayagam, R.; Khan, U.; Marsden, S.; Minty, I.; Moncur, P.; Bain, I.; Yiannakou, Y.J.

2008-01-01

Aim: To compare faecal loading on plain radiography versus radio-opaque marker transit studies in the assessment of constipation. Methods: The study group was a convenience sample of patients attending the Durham Constipation Clinic. All patients underwent transit studies according to an established protocol, and severity of constipation was assessed contemporaneously using a validated questionnaire (PAC-SYM). Transit studies were performed using radio-opaque markers that were ingested over 3 consecutive days, with a radiograph taken on the fourth day. Digital images of the radiograph were digitally altered to remove all traces of the transit markers without affecting the underlying pattern of faecal loading. Four observers assessed faecal loading independently; two clinicians (C1 and C2) and two radiologists (R1 and R2). C1 and R1 used a previously described formal scoring method of assessing faecal loading, whereas C2 and R2 assessed the images as if they were in a clinic or reporting session, grading the faecal loading as mild, moderate, or severe. Results: One hundred patients were recruited out of 186 presenting in a 2-year period. All patients completed assessments. The correlation between observers was only fair to moderate (r ranging from 0.34-0.51). There were some surprisingly marked disagreements in 10-18% of assessments. The correlation between faecal loading and transit was weak for all observers (r ranging from 0.261-0.311). Symptom severity did not correlate with faecal loading. Conclusion: These results suggest that there is considerable inter-observer variation in the radiological assessment of faecal loading, irrespective of the training or method used by the observer, and that there is very poor correlation with colonic transit. The diagnosis of constipation, and the assessment of severity, is best performed clinically

Managing peak loads in energy grids: Comparative economic analysis

International Nuclear Information System (INIS)

Zhuk, A.; Zeigarnik, Yu.; Buzoverov, E.; Sheindlin, A.

2016-01-01

One of the key issues in modern energy technology is managing the imbalance between the generated power and the load, particularly during times of peak demand. The increasing use of renewable energy sources makes this problem even more acute. Various existing technologies, including stationary battery energy storage systems (BESS), can be employed to provide additional power during peak demand times. In the future, integration of on-board batteries of the growing fleet of electric vehicles (EV) and plug-in hybrid electric vehicles (PHEV) into the grid can provide power during peak demand hours (vehicle-to-grid, or V2G technology). This work provides cost estimates of managing peak energy demands using traditional technologies, such as maneuverable power plants, conventional hydroelectric, pumped storage plants and peaker generators, as well as BESS and V2G technologies. The derived estimates provide both per kWh and kW year of energy supplied to the grid. The analysis demonstrates that the use of battery storage is economically justified for short peak demand periods of <1 h. For longer durations, the most suitable technology remains the use of maneuverable steam gas power plants, gas turbine,reciprocating gas engine peaker generators, conventional hydroelectric, pumped storage plants. - Highlights: • Cost of managing peak energy demand employing different technologies are estimated. • Traditional technologies, stationary battery storage and V2G are compared. • Battery storage is economically justified for peak demand periods of <1 h. • V2G appears to have better efficiency than stationary battery storage in low voltage power grids.

Preliminary assessment of the effects of biaxial loading on reactor pressure vessel structural-integrity-assessment technology

International Nuclear Information System (INIS)

Pennell, W.E.; Bass, B.R.; Bryson, J.W.; Dickson, T.L.; McAfee, W.J.; Merkle, J.G.

1996-01-01

Effects of biaxial loading on shallow-flaw fracture toughness were studied to determine potential impact on structural integrity assessment of a reactor pressure vessel (RPV) under pressurized thermal shock (PTS) transient loading and pressure-temperature (PT) loading produced by reactor heatup and cooldown transients. Biaxial shallow-flaw fracture-toughness tests results were also used to determine the parameter controlling fracture in the transition temperature range, and to develop a related dual-parameter fracture-toughness correlation. Shallow-flaw and biaxial loading effects were found to reduce the conditional probability of crack initiation by a factor of nine when the shallow-flaw fracture-toughness K Jc data set, with biaxial-loading effects adjustments, was substituted in place of ASME Code K Ic data set in PTS analyses. Biaxial loading was found to reduce the shallow-flaw fracture toughness of RPV steel such that the lower-bound curve was located between ASME K Ic and K IR curves. This is relevant to future development of P-T curve analysis procedures. Fracture in shallow-flaw biaxial samples tested in the lower transition temperature range was shown to be strain controlled. A strain-based dual-parameter fracture-toughness correlation was developed and shown to be capable of predicting the effect of crack-tip constraint on fracture toughness for strain-controlled fracture

Consequence assessment of floating and storage and off loading (FPSO) systems

International Nuclear Information System (INIS)

Smith, Duncan; Alderman, John A.

2000-01-01

Floating Production, Storage and Off loading (FPSO) systems are increasingly being used for deep water fields where use of traditional platforms and pipelines is not cost effective. The risks associated with FPSOs are inherently different from those for onshore facilities and conventional offshore platforms.This paper focuses on some of the key issues in the application of consequence assessment to FPSOs. A review and illustration of some of the techniques used for analysis of hydrocarbon hazards associated with FPSO operations will be included. Examples covered include evaluation of heat fluxes from a jet fire from an ignited riser leak and evaluation of explosion overpressure from a gas release on the main deck of the FPSO using ARAMAS. The assessment of the impact of smoke inhalation to personnel taking shelter in the accommodation block of the FPSO during a large fire event is also explained. Experiences gained from consequence assessments and quantitative risk analyses performed for offshore platforms, FPSOs, Floating Storage and Off loading (FSO) systems, as well as onshore refinery and petrochemical facilities will be detailed. (author)

Wave loadings acting on innovative rubble mound breakwater for overtopping wave energy conversion

DEFF Research Database (Denmark)

Contestabile, Pasquale; Iuppa, Claudio; Lauro, Enrico Di

2017-01-01

Highlights •An innovative breakwater for overtopping wave energy conversion has been studied. •Physical model tests have been carried out and analysed. •Breakwater design information on loadings acting on various parts of the structure has been presented. •Design formulae and validation of some t...

Passive Method to Reduce Solar Energy Effect on the Cooling Load in Buildings

Directory of Open Access Journals (Sweden)

Orfi J.

2012-10-01

Full Text Available Energy needed for cooling residential and industrial buildings in hot weather countries is the major issue. The period needed for cooling or comfort conditions in those countries exceeds five months and outdoor temperature reaches more than 40 °C. Also, the solar intensity usually high and can reach about one kW per m2. Hence, any attempt to reduce the effect of solar energy on the cooling load is worthy to investigate. The present work analyzes using artificial, naturally ventilated, shading covers to reduce the effect of solar energy. Analytical and numerical analyzes were performed on the effect of adding a ventilated cover to walls and roof exposed to the solar energy.

Online Energy Management Systems for Microgrids: Experimental Validation and Assessment Framework

DEFF Research Database (Denmark)

Hernández, Adriana Carolina Luna; Meng, Lexuan; Aldana, Nelson Leonardo Diaz

2018-01-01

operating costs and load disconnections. The whole energy management system has been tested experimentally in a test bench under both grid-connected and islanded mode. Also, its performance has been proved considering severe mismatches in forecast generation and load. Several experimental results have...

New energy technologies 4. Energy management and energy efficiency

International Nuclear Information System (INIS)

Sabonnadiere, J.C.; Caire, R.; Raison, B.; Quenard, D.; Verneau, G.; Zissis, G.

2007-01-01

This forth tome of the new energy technologies handbook is devoted to energy management and to the improvement of energy efficiency. The energy management by decentralized generation insertion and network-driven load control, analyzes the insertion and management means of small power generation in distribution networks and the means for load management by the network with the aim of saving energy and limiting peak loads. The second part, devoted to energy efficiency presents in a detailed way the technologies allowing an optimal management of energy in buildings and leading to the implementation of positive energy buildings. A special chapter treats of energy saving using new lighting technologies in the private and public sectors. Content: 1 - decentralized power generation - impacts and solutions: threat or opportunity; deregulation; emerging generation means; impact of decentralized generation on power networks; elements of solution; 2 - mastery of energy demand - loads control by the network: stakes of loads control; choice of loads to be controlled; communication needs; measurements and controls for loads control; model and algorithm needs for loads control. A better energy efficiency: 3 - towards positive energy buildings: key data for Europe; how to convert fossil energy consuming buildings into low-energy consuming and even energy generating buildings; the Minergie brand; the PassivHaus or 'passive house' label; the zero-energy house/zero-energy home (ZEH); the zero-energy building (ZEB); the positive energy house; comparison between the three Minergie/PassivHaus/ZEH types of houses; beyond the positive energy building; 4 - light sources and lighting systems - from technology to energy saving: lighting yesterday and today; light sources and energy conversion; energy saving in the domain of lighting: study of some type-cases; what future for light sources. (J.S.)

Validation of an instrumented dummy to assess mechanical aspects of discomfort during load carriage.

Directory of Open Access Journals (Sweden)

Patrick D Wettenschwiler

Full Text Available Due to the increasing load in backpacks and other load carriage systems over the last decades, load carriage system designs have to be adapted accordingly to minimize discomfort and to reduce the risk of injury. As subject studies are labor-intensive and include further challenges such as intra-subject and inter-subject variability, we aimed to validate an instrumented dummy as an objective laboratory tool to assess the mechanical aspects of discomfort. The validation of the instrumented dummy was conducted by comparison with a recent subject study. The mechanical parameters that characterize the static and dynamic interaction between backpack and body during different backpack settings were compared. The second aim was to investigate whether high predictive power (coefficient of determination R2>0.5 in assessing the discomfort of load carriage systems could be reached using the instrumented dummy. Measurements were conducted under static conditions, simulating upright standing, and dynamic conditions, simulating level walking. Twelve different configurations of a typical load carriage system, a commercially available backpack with a hip belt, were assessed. The mechanical parameters were measured in the shoulder and the hip region of the dummy and consisted of average pressure, peak pressure, strap force and relative motion between the system and the body. The twelve configurations consisted of three different weights (15kg, 20kg, and 25kg, combined with four different hip belt tensions (30N, 60N, 90N, and 120N. Through the significant (p<0.05 correlation of the mechanical parameters measured on the dummy with the corresponding values of the subject study, the dummy was validated for all static measurements and for dynamic measurements in the hip region to accurately simulate the interaction between the human body and the load carriage system. Multiple linear regressions with the mechanical parameters measured on the dummy as independent

Energy loading effects in the scaling of atomic xenon lasers

International Nuclear Information System (INIS)

Ohwa, M.; Kushner, M.J.

1990-01-01

The intrinsic power efficiency of the atomic xenon (5d → 6p) infrared (1.73--3.65 μm) laser is sensitive to the rate of pumping due to electron collision mixing of the laser levels. Long duration pumping at moderate power deposition may therefore result in higher energy efficiencies than pumping at higher powers. In this paper the authors examine the consequences of high energy deposition (100's J/1 atm) during long pumping pulses (100's μs) on the intrinsic power and energy efficiency and optimum power deposition of the atomic xenon laser. The dominant effect of high energy loading, gas heating, causes an increase in the electron density and therefore an increase in the electron collision mixing of the laser levels. The optimum power deposition for a given gas density therefore shifts to lower values with increasing gas temperature. For sufficiently long pumping pulses, nonuniform gas heating results in convection and rarification of highly pumped regions. The optimum power deposition therefore shifts to even lower values as the length of the pumping pulse increases. As a result, laser efficiency depends on the spatial distribution of power deposition as well as its magnitude

On the Energy Conversion Efficiency of Piezoelectric Vibration Energy Harvesting Devices

Energy Technology Data Exchange (ETDEWEB)

Kim, Jae Eun [Catholic University of Daegu, Kyungsan (Korea, Republic of)

2015-05-15

To properly design and assess a piezoelectric vibration energy harvester, it is necessary to consider the application of an efficiency measure of energy conversion. The energy conversion efficiency is defined in this work as the ratio of the electrical output power to the mechanical input power for a piezoelectric vibration energy harvester with an impedance-matched load resistor. While previous research works employed the electrical output power for approximate impedance-matched load resistance, this work derives an efficiency measure considering optimally matched resistance. The modified efficiency measure is validated by comparing it with finite element analysis results for piezoelectric vibration energy harvesters with three different values of the electro-mechanical coupling coefficient. New findings on the characteristics of energy conversion and conversion efficiency are also provided for the two different impedance matching methods.

Low-Load Space Conditioning Needs Assessment

Energy Technology Data Exchange (ETDEWEB)

Puttagunta, Srikanth [Consortium for Advanced Residential Buildings, Norwalk, CT (United States)

2015-05-01

With limited low-load options in the HVAC market, many new-construction housing units are being fitted with oversized equipment - thus facing penalties in system efficiency, comfort, and cost. To bridge the gap between currently available HVAC equipment and the rising demand for low-load HVAC equipment in the marketplace, HVAC equipment manufacturers need to be fully aware of multifamily buildings and single-family homes market needs. Over the past decade, Steven Winter Associates, Inc. (SWA) has provided certification and consulting services on hundreds of housing projects and has accrued a large pool of data. CARB compiled and analyzed these data to see what the thermal load ranges are in various multifamily apartments and attached single-family home types (duplex and townhouse). In total, design loads from 941 dwellings from SWA's recent multifamily and attached single-family work across the Northeast and Mid-Atlantic were analyzed. Information on the dwelling characteristics, design loads, and the specifications of installed mechanical equipment were analyzed to determine any trends that exist within the dataset.

Development of load calculation techniques on screw and screw press energy consumption

OpenAIRE

Татарьянц, Максим Сергеевич; Завинский, Сергей Иванович; Трошин, Алексей Георгиевич

2015-01-01

The process of pressing of wood chips in screw machines is researched. It is defined processes taking place in different parts of the screw, formulas allowing to calculate the loads acting on the screw flights, as well as to determine the power required for compression. The unit costs of energy consumption and raw materials in the degree of heat pressing are determined

Quasi-static analysis of wave loadings on spine-based wave energy devices

Energy Technology Data Exchange (ETDEWEB)

Lockett, F.P.; Peatfield, A.M.; West, M.J.

1980-02-01

A report is given on the Wave Energy Research Programme at Lanchester Polytechnic. Results are presented for both theoretical and experimental scale models for wave loadings on circular and rectangular spines of various lengths. The results are in good agreement over the operational wave range for the 1/50 scale model and for the more limited data on the 1/10 scale model.

Heavy-Load Lifting

DEFF Research Database (Denmark)

Bloomquist, Kira; Oturai, Peter; Steele, Megan L

2018-01-01

of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal....... repetition maximum (RM), two sets of 15-20 repetitions) and heavy-load (85-90% 1RM, three sets of 5-8 repetition) upper-extremity resistance exercise separated by a one-week wash-out period. Swelling was determined by bioimpedance spectroscopy and dual energy x-ray absorptiometry, with breast cancer......-related lymphedema symptoms (heaviness, swelling, pain, tightness) reported using a numeric rating scale (0-10). Order of low- versus heavy-load was randomized. All outcomes were assessed pre-, immediately post-, and 24- and 72-hours post-exercise. Generalized estimating equations were used to evaluate changes over...

Fracture Assessment of PEEK under Static Loading by Means of the Local Strain Energy Density

Directory of Open Access Journals (Sweden)

Mirco Peron

2017-12-01

Full Text Available Polyetheretherketone (PEEK has gained interest in many industrial applications due to its high strength-to-weight ratio, excellent heat tolerance and high corrosion resistance. Stress concentrators such as notches and geometrical discontinuities are present in many such components necessitating the reliable assessment of notch sensitivity of PEEK in monotonic tension. Here we evaluate the applicability of the strain energy density (SED approach for the assessment of the fracture strength of experimentally tested notched geometries subject to corrosion. The fracture behavior of neat, circumferentially razor-grooved dog-bone specimens and circumferentially U-notched specimens with different notch radii can be predicted with a discrepancy lower than ±10%. Reliable predictions are shown on two previously published datasets employing both computed and published mechanical properties as inputs for the SED calculations. This report presents the first successful application of SED for PEEK as well as the successful prediction of tensile behavior in corrosive environments. This opens the road towards future applications of PEEK in fields its compliant use is of growing popularity.

Interdependency Assessment of Coupled Natural Gas and Power Systems in Energy Market

Science.gov (United States)

Yang, Hongzhao; Qiu, Jing; Zhang, Sanhua; Lai, Mingyong; Dong, Zhao Yang

2015-12-01

Owing to the technological development of natural gas exploration and the increasing penetration of gas-fired power generation, gas and power systems inevitably interact with each other from both physical and economic points of view. In order to effectively assess the two systems' interdependency, this paper proposes a systematic modeling framework and constructs simulation platforms for coupled gas and power systems in an energy market environment. By applying the proposed approach to the Australian national electricity market (NEM) and gas market, the impacts of six types of market and system factors are quantitatively analyzed, including power transmission limits, gas pipeline contingencies, gas pipeline flow constraints, carbon emission constraints, power load variations, and non-electric gas load variations. The important interdependency and infrastructure weakness for the two systems are well studied and identified. Our work provides a quantitative basis for grid operators and policy makers to support and guide operation and investment decisions for electric power and natural gas industries.

Changes in resonance frequency analysis assessed by Osstell mentor during osseointegration: comparison between immediately loaded implants and control implants without load

Directory of Open Access Journals (Sweden)

M. González-Jaranay

2014-10-01

Full Text Available Aim: The aim of this prospective clinical study was to evaluate the changes in resonance frequency analysis (RFA, assessed by Osstell Mentor, obtaining information on the implant stability quotient (ISQ during implants tissue integration for immediately loaded and non-loaded control implants. Materials and methods: A total of 40 implants, 20 implants with no immediate loading (control and 20 immediately loaded implants (test, were placed in 15 patients. ISQ implants was evaluated at baseline and at 6 and 8 weeks. Provisional crowns were removed at 8 weeks, when the definitive restoration was placed. Data of control and test implants and maxillary and mandibular areas were statistically compared. Results: At 8 weeks, all implants were integrated and there were no major postoperative complications. A statistically significant difference was found only at baseline between test and control maxillary implants (p=0.009 but not at 6 or 8 weeks (p>0.05. Conclusion: Immediate loading procedures may be applied with primary stability ISQ values >60 and inserted with a force of ≥30 N. The Osstell Mentor RFA may offer an objective method to determine when implant stability is adequate for immediate loading.

Strategies for Controlling Plug Loads. A Tool for Reducing Plug Loads in Commercial Buildings

Energy Technology Data Exchange (ETDEWEB)

Torcellini, Paul [National Renewable Energy Lab. (NREL), Golden, CO (United States); Bonnema, Eric [National Renewable Energy Lab. (NREL), Golden, CO (United States); Sheppy, Michael [National Renewable Energy Lab. (NREL), Golden, CO (United States); Pless, Shanti [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2015-09-01

Plug loads are often not considered as part of the energy savings measures in Commercial Buildings; however, they can account for up to 50% of the energy used in the building. These loads are numerous and often scattered throughout a building. Some of these loads are purchased by the owner and some designed into the building or the tenant finishes for a space. This document provides a strategy and a tool for minimizing these loads.

Modeling energy flexibility of low energy buildings utilizing thermal mass

DEFF Research Database (Denmark)

Foteinaki, Kyriaki; Heller, Alfred; Rode, Carsten

2016-01-01

In the future energy system a considerable increase in the penetration of renewable energy is expected, challenging the stability of the system, as both production and consumption will have fluctuating patterns. Hence, the concept of energy flexibility will be necessary in order for the consumption...... to match the production patterns, shifting demand from on-peak hours to off-peak hours. Buildings could act as flexibility suppliers to the energy system, through load shifting potential, provided that the large thermal mass of the building stock could be utilized for energy storage. In the present study...... the load shifting potential of an apartment of a low energy building in Copenhagen is assessed, utilizing the heat storage capacity of the thermal mass when the heating system is switched off for relieving the energy system. It is shown that when using a 4-hour preheating period before switching off...

Fracture assessment of shallow-flaw cruciform beams tested under uniaxial and biaxial loading conditions

International Nuclear Information System (INIS)

Bass, B.R.; McAfee, W.J.; Williams, P.T.; Pennell, W.E.

1999-01-01

A technology to determine shallow-flaw fracture toughness of reactor pressure vessel (RPV) steels is being developed for application to the safety assessment of RPVs containing postulated shallow surface flaws. Matrices of cruciform beam tests were developed to investigate and quantify the effects of temperature, biaxial loading, and specimen size on fracture initiation toughness of two-dimensional (constant depth), shallow, surface flaws. The cruciform beam specimens were developed at Oak Ridge National Laboratory (ORNL) to introduce a far-field, out-of-plane biaxial stress component in the test section that approximates the nonlinear stresses resulting from pressurized-thermal-shock or pressure-temperature loading of an RPV. Tests were conducted under biaxial load ratios ranging from uniaxial to equibiaxial. These tests demonstrated that biaxial loading can have a pronounced effect on shallow-flaw fracture toughness in the lower transition temperature region for an RPV material. The cruciform fracture toughness data were used to evaluate fracture methodologies for predicting the observed effects of biaxial loading on shallow-flaw fracture toughness. Initial emphasis was placed on assessment of stress-based methodologies, namely, the J-Q formulation, the Dodds-Anderson toughness scaling model, and the Weibull approach. Applications of these methodologies based on the hydrostatic stress fracture criterion indicated an effect of loading-biaxiality on fracture toughness; the conventional maximum principal stress criterion indicated no effect. A three-parameter Weibull model based on the hydrostatic stress criterion is shown to correlate with the experimentally observed biaxial effect on cleavage fracture toughness by providing a scaling mechanism between uniaxial and biaxial loading states. (orig.)

Renewable energy the best remedy for electrical load shedding in Pakistan

International Nuclear Information System (INIS)

Bhutta, S.M.

2011-01-01

Average 33% time of daily electrical load shedding in Pakistan is most serious as it has affected all activities. Industries are crippled, commercial, official activities and daily life is being deteriorated Total loss to Export is 1.3 and oil import bill is $ 9 Billion. If appropriate actions are not taken immediately; the situation is going to get worse when people will fight for every watt of electricity. The impounding crises are not foreseen and its gravity is not yet properly realized by the decision makers. Politics and several lobbies work against construction of major projects of hydel power and baseless controversies have been created. Pakistan is blessed with abundant renewable energy i.e. 2.9 million MW solar, tidal, wind 346,000 MW and 59,000 MW potentials of hydro electricity. Analysis of the reasons for the slow and no growth of these vital renewable potentials in Pakistan indicate that there are barriers which need to be mitigated to take immediate benefits to overcome menace of load shedding. Local R and D, Design, manufacturing, installation and feasibility study capabilities are negligible. Institutional capabilities in most of the organizations can at best be ranked as average or weak. Other impediments and barriers that continue to hamper the load shedding are losses, attitude in the promotion of renewable and hydro power projects include: lack of serious attempts to mitigate the barriers, integrate the programs with profitability; inadequate evaluation of resources; non availability of reliable baseline data; and lack of coordination among the relevant agencies; weak institutional arrangements for renewable energy promotion; absence of fiscal and financing mechanisms; lack of understanding, awareness, information and outreach; uneven allocation of resources; lack of appropriate quality management, monitoring and evaluation programs; and need of attractive policy framework and legislative support, building consensus among people and provinces

Ultimate load capacity assessment of reinforced concrete shell structures

International Nuclear Information System (INIS)

Gupta, Amita; Singh, R.K.; Kushwaha, H.S.; Mahajan, S.C.; Kakodkar, A.

1993-01-01

The objective of this study is to develop capability for prediction of ultimate load capacity of reinforced concrete shell structures. The present finite element code ULCA (Ultimate Load Capacity Assessment) adopts a degenerate concept of formulating general isoparametric shell element with a layered approach in the thickness direction. Different failure modes such as crushing, tensile cracking and reinforcement yielding are recognised for various problems. The structure fails by crushing of concrete when the concrete strain/stress reaches the ultimate stress or strain of concrete. Material nonlinearities as a result of tension cracking, tension stiffening between reinforcement and concrete in cracked region and yielding of reinforcement are considered along with geometric nonlinearity. Thus with this code it is possible to predict the pressure at which the first cracking, first through thickness cracking, first yielding of reinforcement occurs. After validating the code with few bench mark problems for different failure modes a reinforced concrete nuclear containment is analysed for its ultimate capacity and the results are matched with the published results. Further the ultimate load capacity of outer containment wall of Narora Atomic Power Station is predicted. It is observed that containment fails in membrane region and has a sufficient margin against design pressure. (author). 9 refs., 56 figs., 3 tabs., 1 appendix with 4 tabs

Miscellaneous and Electronic Loads Energy Efficiency Opportunities for Commercial Buildings: A Collaborative Study by the United States and India

Energy Technology Data Exchange (ETDEWEB)

Ghatikar, Girish [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Cheung, Iris [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Lanzisera, Steven [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Wardell, Bob [Infosys Technologies Limited; Deshpande, Manoj [Infosys Technologies Limited; Ugarkar, Jayraj [Infosys Technologies Limited

2013-04-01

This report documents the technical evaluation of a collaborative research, development, and demonstration (RD&D) project that aims to address energy efficiency of Miscellaneous and Electronic Loads (MELs) (referred to as plug loads interchangeably in this report) using load monitoring and control devices. The goal s of this project are to identify and provide energy efficiency and building technologies to exemplary information technology (IT) office buildings, and to assist in transforming markets via technical assistance and engagement of Indian and U.S. stakeholders. This report describes the results of technology evaluation and United States – India collaboration between the Lawrence Berkeley National Laboratory (LBNL), Infosys Technologies Limited (India), and Smartenit, Inc. (U.S.) to address plug - load efficiency. The conclusions and recommendations focus on the larger benefits of such technologies and their impacts on both U.S. and Indian stakeholders.

Assessment of Wind Parameter Sensitivity on Ultimate and Fatigue Wind Turbine Loads: Preprint

Energy Technology Data Exchange (ETDEWEB)

Robertson, Amy N [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Sethuraman, Latha [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Jonkman, Jason [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Quick, Julian [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2018-02-13

Wind turbines are designed using a set of simulations to ascertain the structural loads that the turbine could encounter. While mean hub-height wind speed is considered to vary, other wind parameters such as turbulence spectra, sheer, veer, spatial coherence, and component correlation are fixed or conditional values that, in reality, could have different characteristics at different sites and have a significant effect on the resulting loads. This paper therefore seeks to assess the sensitivity of different wind parameters on the resulting ultimate and fatigue loads on the turbine during normal operational conditions. Eighteen different wind parameters are screened using an Elementary Effects approach with radial points. As expected, the results show a high sensitivity of the loads to the turbulence standard deviation in the primary wind direction, but the sensitivity to wind shear is often much greater. To a lesser extent, other wind parameters that drive loads include the coherence in the primary wind direction and veer.

Acoustic emission energy b-value for local damage evaluation in reinforced concrete structures subjected to seismic loadings

Science.gov (United States)

Sagasta, Francisco; Zitto, Miguel E.; Piotrkowski, Rosa; Benavent-Climent, Amadeo; Suarez, Elisabet; Gallego, Antolino

2018-03-01

A modification of the original b-value (Gutenberg-Richter parameter) is proposed to evaluate local damage of reinforced concrete structures subjected to dynamical loads via the acoustic emission (AE) method. The modification, shortly called energy b-value, is based on the use of the true energy of the AE signals instead of its peak amplitude, traditionally used for the calculation of b-value. The proposal is physically supported by the strong correlation between the plastic strain energy dissipated by the specimen and the true energy of the AE signals released during its deformation and cracking process, previously demonstrated by the authors in several publications. AE data analysis consisted in the use of guard sensors and the Continuous Wavelet Transform in order to separate primary and secondary emissions as much as possible according to particular frequency bands. The approach has been experimentally applied to the AE signals coming from a scaled reinforced concrete frame structure, which was subjected to sequential seismic loads of incremental acceleration peak by means of a 3 × 3 m2 shaking table. For this specimen two beam-column connections-one exterior and one interior-were instrumented with wide band low frequency sensors properly attached on the structure. Evolution of the energy b-value along the loading process accompanies the evolution of the severe damage at the critical regions of the structure (beam-column connections), thus making promising its use for structural health monitoring purposes.

Assessment of annual pollutant loads in combined sewers from continuous turbidity measurements: sensitivity to calibration data.

Science.gov (United States)

Lacour, C; Joannis, C; Chebbo, G

2009-05-01

This article presents a methodology for assessing annual wet weather Suspended Solids (SS) and Chemical Oxygen Demand (COD) loads in combined sewers, along with the associated uncertainties from continuous turbidity measurements. The proposed method is applied to data from various urban catchments in the cities of Paris and Nantes. The focus here concerns the impact of the number of rain events sampled for calibration (i.e. through establishing linear SS/turbidity or COD/turbidity relationships) on the uncertainty of annual pollutant load assessments. Two calculation methods are investigated, both of which rely on Monte Carlo simulations: random assignment of event-specific calibration relationships to each individual rain event, and the use of an overall relationship built from the entire available data set. Since results indicate a fairly low inter-event variability for calibration relationship parameters, an accurate assessment of pollutant loads can be derived, even when fewer than 10 events are sampled for calibration purposes. For operational applications, these results suggest that turbidity could provide a more precise evaluation of pollutant loads at lower cost than typical sampling methods.

Use of Natural-Fiber Bio-Composites in Construction versus Traditional Solutions: Operational and Embodied Energy Assessment.

Science.gov (United States)

Galan-Marin, Carmen; Rivera-Gomez, Carlos; Garcia-Martinez, Antonio

2016-06-13

During the last decades natural polymers have become more and more frequent to replace traditional inorganic stabilizers in building materials. The purpose of this research is to establish a comparison between the most conventional building material solutions for load-bearing walls and a type of biomaterial. This comparison will focus on load-bearing walls as used in a widespread type of twentieth century dwelling construction in Europe and still used in developing countries nowadays. To carry out this analysis, the structural and thermal insulation characteristics of different construction solutions are balanced. The tool used for this evaluation is the life cycle assessment throughout the whole lifespan of these buildings. This research aims to examine the environmental performance of each material assessed: fired clay brick masonry walls (BW), concrete block masonry walls (CW), and stabilized soil block masonry walls (SW) stabilized with natural fibers and alginates. These conventional and new materials are evaluated from the point of view of both operational and embodied energy.

The Methodology for Integral Assessment of the Impact of Renewable Energy on the Environment under Non-Stationary Economy

Directory of Open Access Journals (Sweden)

Petrakov Iaroslav V.

2017-12-01

Full Text Available The need to reduce anthropogenic load, eliminate threats to environmental safety and provide ecologically oriented development are one of the main global challenges of our time. At the same time, the replacement of traditional energy sources with alternatives ones requires a quantitative assessment of direct and indirect environmental impacts. The article analyzes the dynamics and structure of pollution in Ukraine in terms of its sources and forms as well as their impact on the carbon productivity of the GDP. It is proposed to assess the impact of alternative energy on the environment under non-stationary economy using an integral indicator that takes into account a number of factors, in particular the change in the share of RES in the total primary energy supply, share of renewable energy production, the index of greenhouse gases by the energy sector, change in the quality of atmospheric air in the urban populated area, amount of investment in reducing CO2 emissions, carbon intensity of energy production, share of thermal generation capacity that meets the ecological requirements of the EU.

Theoretical analysis, infrared and structural investigations of energy dissipation in metals under cyclic loading

International Nuclear Information System (INIS)

Plekhov, O.A.; Saintier, N.; Palin-Luc, T.; Uvarov, S.V.; Naimark, O.B.

2007-01-01

The infrared and structural investigations of energy dissipation processes in metals subjected to cyclic loading have given impetus to the development of a new thermodynamic model with the capability of describing the energy balance under plastic deformation. The model is based on the statistical description of the mesodefect ensemble evolution and its influence on the dissipation ability of the material. Constitutive equations have been formulated for plastic and structural strains, which allow us to describe the stored and dissipated parts of energy under plastic flow. Numerical results indicate that theoretical predictions are in good agreement with the experimentally observed temperature data

Green energy criteria and life cycle assessment in assessing environmental competitiveness of energy products

International Nuclear Information System (INIS)

Maelkki, H.; Hongisto, M.; Turkulainen, T.; Kuisma, J.; Loikkanen, T.

1999-01-01

The liberalisation of energy markets has increased the need to enlarge the information base of fuel chains, to evaluate the environmental quality of energy products transparently and to communicate results in a credible way. The preparedness of energy purchasers, producers and sellers to support energy choices of their customers and to meet the information requirements of various stake holders can be strengthened. The environmental impacts related to energy products are turning into a significant dimension of competitiveness. Possibilities to promote market-driven environmental protection mechanisms and to construct incentives, which cover the whole energy production system exist and can be supported. Knowledge of environmental impacts of various energy products can be increased by means of several supplementary instruments like eco-profiles, environmental labels and life cycle assessments of products. Life cycle assessment forms a systematic basis of information, which supports the environmental communications directed to various stake holders. In this study selected public LCA-studies concerning energy production have been compared, criteria of green energy have been charted and their outlook has been assessed. In addition the development of an LCA- based relative environmental performance indicator system, which supports various transparent comparisons, has been outlined. The mapping of methodological differences of published LCA-studies regarding various energy alternatives proves, that there is differences e.g. in allocation principles, system boundaries, and age of source information and in many other details. These discrepancies should be known, because they also affect the results. That is why the use of available LCA studies as a basis for comparative assertions may be problematic. The renewability of an energy source is a threshold requirement in eco-energy criteria formulated and introduced by Finnish, Swedish and Norwegian nature conservation

Fatigue and Serviceability Limit State Model Basis for Assessment of Offshore Wind Energy Converters

DEFF Research Database (Denmark)

Thöns, Sebastian; Faber, M. H.; Rücker, W.

2012-01-01

, a probabilistic model is derived on the basis of literature review and measurement data from a prototype Multibrid M5000 support structure. The sensitivity study is based on the calculation of a nonlinear coefficient of correlation in conjunction with predetermined designs of experiments. This is conducted......This paper develops the models for the structural performance of the loading and probabilistic characterization for the fatigue and the serviceability limit states for the support structure of offshore wind energy converters. These models and a sensitivity study are part of a risk based assessment...... as the starting point for the development of the structural performance and loading models. With these models introduced in detail, several modeling aspects for both limit states are analyzed. This includes analyses of the influence on the hot spot stresses by applying a contact formulation for the pile guide...

Wave Loadings Acting on an Innovative Breakwater for Energy Production

DEFF Research Database (Denmark)

Vicinanza, Diego; Ciardulli, F.; Buccino, M.

2011-01-01

The paper reports on 2D small scale experiments conducted to investigate wave loadings acting on a pilot project of device for the conversion of wave energy into electricity. The conversion concept is based on the overtopping principle and the structure is worldwide known with the acronym SSG....... The hydraulic model tests have been carried out at the LInC laboratory of the University of Naples Federico II using random waves. Results indicate wave overtopping is able to cause a sudden inversion of vertical force under wave crest, so that it is alternatively upward and downward directed over a short time...

Energy recovery from waste incineration: Assessing the importance of district heating networks

International Nuclear Information System (INIS)

Fruergaard, T.; Christensen, T.H.; Astrup, T.

2010-01-01

Municipal solid waste incineration contributes with 20% of the heat supplied to the more than 400 district heating networks in Denmark. In evaluation of the environmental consequences of this heat production, the typical approach has been to assume that other (fossil) fuels could be saved on a 1:1 basis (e.g. 1 GJ of waste heat delivered substitutes for 1 GJ of coal-based heat). This paper investigates consequences of waste-based heat substitution in two specific Danish district heating networks and the energy-associated interactions between the plants connected to these networks. Despite almost equal electricity and heat efficiencies at the waste incinerators connected to the two district heating networks, the energy and CO 2 accounts showed significantly different results: waste incineration in one network caused a CO 2 saving of 48 kg CO 2 /GJ energy input while in the other network a load of 43 kg CO 2 /GJ. This was caused mainly by differences in operation mode and fuel types of the other heat producing plants attached to the networks. The paper clearly indicates that simple evaluations of waste-to-energy efficiencies at the incinerator are insufficient for assessing the consequences of heat substitution in district heating network systems. The paper also shows that using national averages for heat substitution will not provide a correct answer: local conditions need to be addressed thoroughly otherwise we may fail to assess correctly the heat recovery from waste incineration.

Load shifting with the use of home energy management system implemented in FPGA

Science.gov (United States)

Bazydło, Grzegorz; Wermiński, Szymon

2017-08-01

The increases for power demand in the Electrical Power System (EPS) causes a significant increase of power in daily load curve and transmission line overload. The large variability in energy consumption in EPS combined with unpredictable weather events can lead to a situation in which to save the stability of the EPS, the power limits must be introduced or even industrial customers in a given area have to be disconnected, which causes financial losses. Nowadays, a Transmission System Operator is looking for additional solutions to reduce peak power, because existing approaches (mainly building new intervention power unit or tariff programs) are not satisfactory due to the high cost of services in combination with insufficient power reduction effect. The paper presents an approach to load shifting with the use of home Energy Management System (EMS) installed at small end-users. The home energy management algorithm, executed by EMS controller, is modeled using Unified Modeling Language (UML). Then, the UML model is translated into Verilog description, and is finally implemented in the Field Programmable Gate Arrays. The advantages of the proposed approach are the relatively low cost of reduction service, small loss of end-users' comfort, and the convenient maintenance of EMS. A practical example illustrating the proposed approach and calculation of potential gains from its implementation are also presented.

Power flow control strategy in distribution network for dc type distributed energy resource at load bus

International Nuclear Information System (INIS)

Hanif, A.; Choudhry, M.A.

2013-01-01

This research work presents a feed forward power flow control strategy in the secondary distribution network working in parallel with a DC type distributed energy resource (DER) unit with SPWM-IGBT Voltage Source Converter (VSC). The developed control strategy enables the VSC to be used as power flow controller at the load bus in the presence of utility supply. Due to the investigated control strategy, power flow control from distributed energy resource (DER) to common load bus is such that power flows to the load without facing any power quality problem. The technique has an added advantage of controlling power flow without having a dedicated power flow controller. The SPWM-IGBT VSC is serving the purpose of dc-ac converter as well as power flow controller. Simulations for a test system using proposed power flow control strategy are carried out using SimPower Systems toolbox of MATLAB at the rate and Simulink at the rate. The results show that a reliable, effective and efficient operation of DC type DER unit in coordination with main utility network can be achieved. (author)

Thermal Energy Storage for Building Load Management: Application to Electrically Heated Floor

Directory of Open Access Journals (Sweden)

Hélène Thieblemont

2016-07-01

Full Text Available In cold climates, electrical power demand for space conditioning becomes a critical issue for utility companies during certain periods of the day. Shifting a portion or all of it to off-peak periods can help reduce peak demand and reduce stress on the electrical grid. Sensible thermal energy storage (TES systems, and particularly electrically heated floors (EHF, can store thermal energy in buildings during the off-peak periods and release it during the peak periods while maintaining occupants’ thermal comfort. However, choosing the type of storage system and/or its configuration may be difficult. In this paper, the performance of an EHF for load management is studied. First, a methodology is developed to integrate EHF in TRNSYS program in order to investigate the impact of floor assembly on the EHF performance. Then, the thermal comfort (TC of the night-running EHF is studied. Finally, indicators are defined, allowing the comparison of different EHF. Results show that an EHF is able to shift 84% of building loads to the night while maintaining acceptable TC in cold climate. Moreover, this system is able to provide savings for the customer and supplier if there is a significant difference between off-peak and peak period electricity prices.

The role of grid-connected, building-integrated photovoltaic generation in commercial building energy and power loads in a warm and sunny climate

International Nuclear Information System (INIS)

Braun, P.; Ruether, R.

2010-01-01

For large commercial buildings, power load delivery limits are contracted with the local electricity distribution utility, and are usually fixed at one or more levels over the year, according to the seasonal building loads, and depending on the specific country regulations. Especially in warm and sunny climates, solar electricity generation using building-integrated photovoltaics (BIPV) can assist in reducing commercial building loads, offering peak-shaving (power) benefits on top of the on-site generation of electricity (energy). This on-site power delivery capability gives these consumers the possibility of renegotiating demand contracts with their distribution utility. Commercial buildings that operate during daytime quite often have an energy consumption profile that is well matched by solar radiation availability, and depending on the building's available surface areas, BIPV can generate considerable portions of the energy requirements. In this work we present the role of grid-connected BIPV in reducing the load demands of a large and urban commercial building located in a warm climate in Brazil. The building and adjacent car parking lots can accommodate a 1 MWp BIPV generator, which closely matches the building's typical maximum power demands. Based on real solar radiation data and simultaneous building electricity demands for the year 2007, simulation of the annual solar generation profile of this on-site generator showed that the 1 MWp BIPV system could account for around 30% of the total building's energy consumption. In addition to the energy benefit, maximum power demands were reduced due to a good match between midday air-conditioning cooling loads and solar radiation availability on both a daily and seasonal basis. Furthermore, we have simulated the effect of this considerably large urban-sited generator on the local distribution network load, and have shown that the 1 MWp BIPV installation can also offer considerable benefits to the local utility in

Social assessment of energy projects. How?

International Nuclear Information System (INIS)

Munksgaard, J.; Larsen, A.

1997-08-01

This is the final report of the project: Social assessment of Energy Projects. The aim of the project is to improve the basis of working out social assessments of energy projects in practice. The report raises the question: How should social assessments of energy projects be made? A social assessment is using a national perspective, i.e. it accounts the effects of the project for individuals and institutions in Denmark. The assessment is based on economics which means that effects generated by the project are valuated in DKK - as far as possible. The aim of the social assessment is to support a more effective use of the resources in Denmark. A social assessment should include an analysis of the distributional effects. The analysis can be made as an account including a social cash flow analysis. The distribution analysis will illustrate the gains and losses for the different groups of individuals affected carrying out the project. In that way the analysis will show who potentially will support the project and who will be against the project. (EG) EFP-92. 37 refs

Relative absorption and dermal loading of chemical substances: Consequences for risk assessment

NARCIS (Netherlands)

Buist, H.E.; Schaafsma, G.; Sandt, J.J.M. van de

2009-01-01

Quantification of skin absorption is an essential step in reducing the uncertainty of dermal risk assessment. Data from literature indicate that the relative dermal absorption of substances is dependent on dermal loading. Therefore, an internal exposure calculated with absorption data determined at

A method for rapid vulnerability assessment of structures loaded by outside blasts

International Nuclear Information System (INIS)

Cizelj, Leon; Leskovar, Matjaz; Cepin, Marko; Mavko, Borut

2009-01-01

The blast loads have in most cases not been assumed as design basis loads of nuclear power plant buildings and structures. Recent developments however stimulated a number of analyses quantifying the potential effects of such loads. An effort was therefore made by the authors to revisit simple and robust structural analysis methods and to propose their use in the vulnerability assessment of blast-loaded structures. The leading idea is to break the structure into a set of typical structural elements, for which the response is estimated by the use of slightly modified handbook formulas. The proposed method includes provisions to predict the inelastic response and failure. Simplicity and versatility of the method facilitate its use in structural reliability calculations. The most important aspects of the proposed method are presented along with illustrative sample applications demonstrating: ·results comparable to full scale dynamic simulations using explicit finite element codes and ·the performance of the method in screening the existing structures and providing the structural reliability information for the vulnerability analysis.

Assessment of integrity for the pressure vessel internals of PWRs under blowdown loadings

International Nuclear Information System (INIS)

Geiss, M.; Benner, J.; Ludwig, A.

1984-01-01

In safety analysis of pressurized water reactors the loss-of-coolant accident plays a central role. Thereby a sudden break of a cold primary coolant pipe close to the reactor pressure vessel is postulated. The sudden pressure release of the primary system (blowdown) causes high dynamic loading on the pressure vessel internals. The resulting deformations must not impair shut down of the reactor and decay heat removal in an inadmissible way. For this assessment a blowdown analysis for a 1300 MW pressurized water reactor is carried out. These investigations are completed with a detailed stress analysis for the highly loaded core barrel clamping. The results show that the reactor pressure vessel internals are able to withstand blowdown loading. Even in case of a sudden and complete break of the primary coolant pipe the loading has to be twice as high to endanger the structural integrity. (orig.) [de

Improving urban district heating systems and assessing the efficiency of the energy usage therein

Science.gov (United States)

Orlov, M. E.; Sharapov, V. I.

2017-11-01

The report describes issues in connection with improving urban district heating systems from combined heat power plants (CHPs), to propose the ways for improving the reliability and the efficiency of the energy usage (often referred to as “energy efficiency”) in such systems. The main direction of such urban district heating systems improvement suggests transition to combined heating systems that include structural elements of both centralized and decentralized systems. Such systems provide the basic part of thermal power via highly efficient methods for extracting thermal power plants turbines steam, while peak loads are covered by decentralized peak thermal power sources to be mounted at consumers’ locations, with the peak sources being also reserve thermal power sources. The methodology was developed for assessing energy efficiency of the combined district heating systems, implemented as a computer software product capable of comparatively calculating saving on reference fuel for the system.

Balancing Power Absorption and Structural Loading for an Assymmetric Heave Wave-Energy Converter in Regular Waves: Preprint

Energy Technology Data Exchange (ETDEWEB)

Tom, Nathan M.; Madhi, Farshad; Yeung, Ronald W.

2016-07-01

The aim of this paper is to maximize the power-to-load ratio of the Berkeley Wedge: a one-degree-of-freedom, asymmetrical, energy-capturing, floating breakwater of high performance that is relatively free of viscosity effects. Linear hydrodynamic theory was used to calculate bounds on the expected time-averaged power (TAP) and corresponding surge restraining force, pitch restraining torque, and power take-off (PTO) control force when assuming that the heave motion of the wave energy converter remains sinusoidal. This particular device was documented to be an almost-perfect absorber if one-degree-of-freedom motion is maintained. The success of such or similar future wave energy converter technologies would require the development of control strategies that can adapt device performance to maximize energy generation in operational conditions while mitigating hydrodynamic loads in extreme waves to reduce the structural mass and overall cost. This paper formulates the optimal control problem to incorporate metrics that provide a measure of the surge restraining force, pitch restraining torque, and PTO control force. The optimizer must now handle an objective function with competing terms in an attempt to maximize power capture while minimizing structural and actuator loads. A penalty weight is placed on the surge restraining force, pitch restraining torque, and PTO actuation force, thereby allowing the control focus to be placed either on power absorption or load mitigation. Thus, in achieving these goals, a per-unit gain in TAP would not lead to a greater per-unit demand in structural strength, hence yielding a favorable benefit-to-cost ratio. Demonstrative results in the form of TAP, reactive TAP, and the amplitudes of the surge restraining force, pitch restraining torque, and PTO control force are shown for the Berkeley Wedge example.

Save Energy Now Assessments Results 2008 Detailed Report

Energy Technology Data Exchange (ETDEWEB)

Wright, Anthony L [ORNL; Martin, Michaela A [ORNL; Nimbalkar, Sachin U [ORNL; Quinn, James [U.S. Department of Energy; Glatt, Ms. Sandy [DOE Industrial Technologies Program; Orthwein, Mr. Bill [U.S. Department of Energy

2010-09-01

In October 2005, U.S. Department of Energy Secretary Bodman launched his Easy Ways to Save Energy campaign with a promise to provide energy assessments to 200 of the largest U.S. manufacturing plants. DOE's Industrial Technologies Program (ITP) responded to the Secretary's campaign with its Save Energy Now initiative, featuring a new and highly cost-effective form of energy savings assessment. The approach for these assessments drew heavily on the existing resources of ITP's technology delivery component. Over the years, ITP Technology Delivery has worked with industry partners to assemble a suite of respected software tools, proven assessment protocols, training curricula, certified energy experts, and strong partnerships for deployment. The Save Energy Now assessments conducted in calendar year 2006 focused on natural gas savings and targeted many of the nation's largest manufacturing plants - those that consume at least 1 TBtu of energy annually. The 2006 Save Energy Now assessments focused primarily on assessments of steam and process heating systems, which account for an estimated 74% of all natural gas use by U.S. manufacturing plants. Because of the success of the Save Energy Now assessments conducted in 2006 and 2007, the program was expanded and enhanced in two major ways in 2008: (1) a new goal was set to perform at least 260 assessments; and (2) the assessment focus was expanded to include pumping, compressed air, and fan systems in addition to steam and process heating. DOE ITP also has developed software tools to assess energy efficiency improvement opportunities in pumping, compressed air, and fan systems. The Save Energy Now assessments integrate a strong training component designed to teach industrial plant personnel how to use DOE's opportunity assessment software tools. This approach has the advantages of promoting strong buy-in of plant personnel for the assessment and its outcomes and preparing them better to

Scheduling of radio-controlled heating load

International Nuclear Information System (INIS)

Fox, B.; McCartney, A.I.; McCann, B.M.

1998-01-01

An economic loading program has been adapted to enable it to obtain an optimum heat-load profile to meet the forecast heat requirement. The heat load is represented by a 'generator' whose load is constrained to be negative. The incremental cost of this unit is a heat energy price. This is adjusted to obtain a heat profile containing the requisite energy. The profile is then used by a dynamic programming algorithm to derive a commitment pattern for each block. A case study is presented which shows that the procedure can minimise heat energy cost. It is also shown that use of the proposed method results in less generator load cycling. This reduced regulation duty should improve reliability. (author)

Investigating Theoretical PV Energy Generation Patterns with Their Relation to the Power Load Curve in Poland

Directory of Open Access Journals (Sweden)

Jakub Jurasz

2016-01-01

Full Text Available Polish energy sector is (almost from its origin dominated by fossil fuel feed power. This situation results from an abundance of relatively cheap coal (hard and lignite. Brown coal due to its nature is the cheapest energy source in Poland. However, hard coal which fuels 60% of polish power plants is picking up on prices and is susceptible to the coal imported from neighboring countries. Forced by the European Union (EU regulations, Poland is struggling at achieving its goal of reaching 15% of energy consumption from renewable energy sources (RES by 2020. Over the year 2015, RES covered 11.3% of gross energy consumption but this generation was dominated by solid biomass (over 80%. The aim of this paper was to answer the following research questions: What is the relation of irradiation values to the power load on a yearly and daily basis? and how should photovoltaics (PV be integrated in the polish power system? Conducted analysis allowed us to state that there exists a negative correlation between power demand and irradiation values on a yearly basis, but this is likely to change in the future. Secondly, on average, daily values of irradiation tend to follow power load curve over the first hours of the day.

Commercial Building Energy Saver: An energy retrofit analysis toolkit

International Nuclear Information System (INIS)

Hong, Tianzhen; Piette, Mary Ann; Chen, Yixing; Lee, Sang Hoon; Taylor-Lange, Sarah C.; Zhang, Rongpeng; Sun, Kaiyu; Price, Phillip

2015-01-01

Highlights: • Commercial Building Energy Saver is a powerful toolkit for energy retrofit analysis. • CBES provides benchmarking, load shape analysis, and model-based retrofit assessment. • CBES covers 7 building types, 6 vintages, 16 climates, and 100 energy measures. • CBES includes a web app, API, and a database of energy efficiency performance. • CBES API can be extended and integrated with third party energy software tools. - Abstract: Small commercial buildings in the United States consume 47% of the total primary energy of the buildings sector. Retrofitting small and medium commercial buildings poses a huge challenge for owners because they usually lack the expertise and resources to identify and evaluate cost-effective energy retrofit strategies. This paper presents the Commercial Building Energy Saver (CBES), an energy retrofit analysis toolkit, which calculates the energy use of a building, identifies and evaluates retrofit measures in terms of energy savings, energy cost savings and payback. The CBES Toolkit includes a web app (APP) for end users and the CBES Application Programming Interface (API) for integrating CBES with other energy software tools. The toolkit provides a rich set of features including: (1) Energy Benchmarking providing an Energy Star score, (2) Load Shape Analysis to identify potential building operation improvements, (3) Preliminary Retrofit Analysis which uses a custom developed pre-simulated database and, (4) Detailed Retrofit Analysis which utilizes real-time EnergyPlus simulations. CBES includes 100 configurable energy conservation measures (ECMs) that encompass IAQ, technical performance and cost data, for assessing 7 different prototype buildings in 16 climate zones in California and 6 vintages. A case study of a small office building demonstrates the use of the toolkit for retrofit analysis. The development of CBES provides a new contribution to the field by providing a straightforward and uncomplicated decision

An adaptive clustering approach to dynamic load balancing and energy efficiency in wireless sensor networks

International Nuclear Information System (INIS)

Gherbi, Chirihane; Aliouat, Zibouda; Benmohammed, Mohamed

2016-01-01

Clustering is a well known approach to cope with large nodes density and efficiently conserving energy in Wireless Sensor Networks (WSN). Load balancing is an effective approach for optimizing resources like channel bandwidth, the main objective of this paper is to combine these two valuable approaches in order to significantly improve the main WSN service such as information routing. So, our proposal is a routing protocol in which load traffic is shared among cluster members in order to reduce the dropping probability due to queue overflow at some nodes. To this end, a novel hierarchical approach, called Hierarchical Energy-Balancing Multipath routing protocol for Wireless Sensor Networks (HEBM) is proposed. The HEBM approach aims to fulfill the following purposes: decreasing the overall network energy consumption, balancing the energy dissipation among the sensor nodes and as direct consequence: extending the lifetime of the network. In fact, the cluster-heads are optimally determined and suitably distributed over the area of interest allowing the member nodes reaching them with adequate energy dissipation and appropriate load balancing utilization. In addition, nodes radio are turned off for fixed time duration according to sleeping control rules optimizing so their energy consumption. The performance evaluation of the proposed protocol is carried out through the well-known NS2 simulator and the exhibited results are convincing. Like this, the residual energy of sensor nodes was measured every 20 s throughout the duration of simulation, in order to calculate the total number of alive nodes. Based on the simulation results, we concluded that our proposed HEBM protocol increases the profit of energy, and prolongs the network lifetime duration from 32% to 40% compared to DEEAC reference protocol and from 25% to 28% compared to FEMCHRP protocol. The authors also note that the proposed protocol is 41.7% better than DEEAC with respect to FND (Fist node die), and 25

The Effect of Electric Load Profiles on the Performance of Off-Grid Residential Hybrid Renewable Energy Systems

Directory of Open Access Journals (Sweden)

Stephen Treado

2015-10-01

Full Text Available This paper investigates the energy performance of off-grid residential hybrid renewable electric power systems, particularly the effect of electric load profiles on the ability to harvest available solar energy and avoid the consumption of auxiliary energy in the form of propane. The concepts are illustrated by an analysis of the energy performance of electric and propane-fired refrigerators. Off-grid electric power systems frequently incorporate a renewable source, such as wind or solar photovoltaic (PV, with a back-up power provided by a propane fueled motor/generator. Among other design decisions, residential consumers face the choice of employing an electric refrigerator with a conventional vapor compression refrigeration system, or a fuel-fired refrigerator operating as an absorption refrigeration system. One interesting question is whether it is more advantageous from an energy perspective to use electricity to run the refrigerator, which might be provided by some combination of the PV and propane motor/generator, thereby taking advantage of the relatively higher electric refrigerator Coefficient of Performance (COP and free solar energy but having to accept a low electrical conversion efficiency of the motor/generator, or use thermal energy from the combustion of propane to produce the refrigeration effect via an absorption system, albeit with a much lower COP. The analysis is complicated by the fact that most off-grid renewable electrical power systems utilize a battery bank to provide electrical power when it is not available from the wind turbine or PV system, so the state of charge of the battery bank will have a noticeable impact on what energy source is available at any moment in time. Daily electric load profiles combined with variable solar energy input determine the state of charge of the battery bank, with the degree of synchronization between the two being a critical factor in determining performance. The annual energy usage

Reducing Plug Loads in Office Spaces: Hawaii and Guam Energy Improvement Technology Demonstration Project

Energy Technology Data Exchange (ETDEWEB)

Sheppy, M. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Metzger, I. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Cutler, D. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Holland, G. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Hanada, A. [Naval Facilities Engineering Command, Washington, DC (United States)

2014-01-01

As part of its overall strategy to meet its energy goals, the Naval Facilities Engineering Command (NAVFAC) partnered with the Department of Energy's National Renewable Energy Laboratory (NREL) to rapidly demonstrate and deploy cost-effective renewable energy and energy efficiency technologies. This project was one of several demonstrations of new or underutilized commercial energy technologies. The common goal was to demonstrate and measure the performance and economic benefit of the system while monitoring any ancillary impacts to related standards of service and operation and maintenance (O&M) practices. In short, demonstrations at naval facilities simultaneously evaluate the benefits and compatibility of the technology with the U.S. Department of Defense (DOD) mission, and with NAVFAC's design, construction, operations, and maintenance practices, in particular. This project demonstrated the performance of commercially available advanced power strips (APSs) for plug load energy reductions in building A4 at Joint Base Pearl Harbor-Hickam (JBPHH), Hawaii.

Allostatic Load Assessment for Early Detection of Stress in the Workplace in Egypt.

Science.gov (United States)

Ali, Ola Sayed; Badawy, Nadia; Rizk, Sanaa; Gomaa, Hend; Saleh, Mai Sabry

2016-09-15

Workplace stress is hazardous for its harmful impact on employees' health and organizational productivity. The aim of the study is to apply the Allostatic Load Index (ALI) which is a multi-component measure for health risk assessment and early detection of stress among workers in Egypt. Sixty-two working adults randomly selected from two different working environments in Egypt were included in the study. Participants completed a self-reported questionnaire for socio-demographic and work variables. Andrews and Withey test for Job Satisfaction was filled and 3 ml blood samples were collected. Markers assessed for Allostatic Load were serum cortisol, c-reactive protein, dehydroepiandrosterone-sulphate, total thyroxine, total cholesterol, triglycerides, low-density lipoprotein, high-density lipoprotein, total cholesterol to high-density lipoprotein ratio, systolic and diastolic blood pressures, waist to hip ratio and body mass index. The risk quartile method was used for calculation of ALI. ALI value of four or more indicates high Allostatic Load. Job satisfaction scale defined about a quarter of the study population (24%) to be dissatisfied with Allostatic Load of 2.4 as the mean value. Population percentage with ALI ≥4 reached 12.9% with 100% of them females. A significant association was found between Allostatic Load of primary mediators and age, the presence of chronic diseases, place of work and female gender. Female gender and the old age of the Egyptian workforce under study are at higher risk of chronic diseases. Using an alternative way -for example, the cut-point method- instead of the risk quartiles for dichotomization of markers used in ALI calculation could be more precise for early detection of stress among healthy individuals.

Mobile loading transuranic waste at small quantity sites in the Department of Energy complex-10523

International Nuclear Information System (INIS)

Carter, Mitch; Howard, Bryan; Weyerman, Wade; Mctaggart, Jerri

2009-01-01

Los Alamos National Laboratory, Carlsbad Office (LANL-CO), operates mobile loading operations for all of the large and small quantity transuranic (TRU) waste sites in the Department of Energy (DOE) complex. The mobile loading team performs loading and unloading evolutions for both contact handled (CH) and remote handled (RH) waste. For small quantity sites, many of which have yet to remove their TRU waste, the mobile loading team will load shipments that will ship to Idaho National Laboratory, a centralization site, or ship directly to the Waste Isolation Pilot Plant (WIPP). For example, Argonne National Laboratory and General Electric Vallecitos Nuclear Center have certified programs for RH waste so they will ship their RH waste directly to WIPP. Many of the other sites will ship their waste to Idaho for characterization and certification. The Mobile Loading Units (MLU) contain all of the necessary equipment needed to load CH and RH waste into the appropriate shipping vessels. Sites are required to provide additional equipment, such as cranes, fork trucks, and office space. The sites are also required to provide personnel to assist in the shipping operations. Each site requires a site visit from the mobile loading team to ensure that all of the necessary site equipment, site requirements and space for shipping can be provided. The mobile loading team works diligently with site representatives to ensure that all safety and regulatory requirements are met. Once the waste is ready and shipping needs are met, the mobile loading team can be scheduled to ship the waste. The CH MLU is designed to support TRUPACT-II and HalfPACT loading activities wherever needed within the DOE complex. The team that performs the mobile loading operation has obtained national certification under DOE for TRUPACT-II and HalfPACT loading and shipment certification. The RH MLU is designed to support removable lid canister (RLC) and RH-72B cask loading activities wherever needed within the DOE

Vibration and Energy Dissipation of Nanocomposite Laminates for Below Ballistic Impact Loading

Directory of Open Access Journals (Sweden)

G. Balaganesan

Full Text Available Abstract Composite laminates are made of glass woven roving mats of 610gsm, epoxy resin and nano clay which are subjected to projectile impact. Nano clay dispersion is varied from 1% to 5%. Impact tests are conducted in a gas gun setup with a spherical nose cylindrical projectile of diameter 9.5 mm of mass 7.6 g. The energy absorbed by the laminates when subjected to impact loading is studied, the velocity range is below ballistic limit. The effect of nano clay on energy absorption in vibration, delamination and matrix crack is studied for different weight % of nano clay and for different thickness values of the laminates. The natural frequencies and damping factors are obtained for the laminates during impact and the effect of nano clay is studied. The results show considerable improvement in energy absorption due to the presence of nano clay

Indirect Load Control for Energy Storage Systems Using Incentive Pricing under Time-of-Use Tariff

Directory of Open Access Journals (Sweden)

Mu-Gu Jeong

2016-07-01

Full Text Available Indirect load control (ILC is a method by which the customer determines load reduction of electricity by using a price signal. One of the ILCs is a time-of-use (TOU tariff, which is the most commonly used time-varying retail pricing. Under the TOU tariff, the customer can reduce the energy cost through an energy storage system (ESS. However, because this tariff is fixed for several months, the ESS operation does not truly reflect the wholesale market price, which could widely fluctuate. To overcome this limitation, this paper proposes an incentive pricing method in which the load-serving entity (LSE gives the incentive pricing signal to the customers with ESSs. Because the ESS charging schedule is determined by the customer through ILC, a bilevel optimization problem that includes the customer optimization problem is utilized to determine the incentive pricing signal. Further, the bilevel optimization problem is reformulated into a one-level problem to be solved by an interior point method. In the proposed incentive scheme: (1 the social welfare increases and (2 the increased social welfare can be equitably divided between the LSE and the customer; and (3 the proposed incentive scheme leads the customer to voluntarily follow the pricing signal.

A design of cascade control system and adaptive load compensator for battery/ultracapacitor hybrid energy storage-based direct current microgrid

International Nuclear Information System (INIS)

Pavković, Danijel; Lobrović, Mihael; Hrgetić, Mario; Komljenović, Ante

2016-01-01

Highlights: • Battery/ultracapacitor storage is considered for a direct-current microgrid. • Microgrid voltage cascade control system with load compensator is designed. • Current references are allocated so that ultracapacitor takes on transient loads. • Adaptive Kalman filter-based estimator is used for indirect load compensation. • Control strategy has been verified on a downscaled hardware-in-the-loop setup. - Abstract: A control system design based on an actively-controlled battery/ultracapacitor hybrid energy storage system suitable for direct current microgrid energy management purposes is presented in this paper. The proposed cascade control system arrangement is based on the superimposed proportional–integral voltage controller designed according to Damping Optimum criterion and a zero-pole canceling feed-forward load compensator aimed at voltage excursion suppression under variable load conditions. The superimposed controller commands the inner battery and ultracapacitor current control loops through a dynamic current reference distribution scheme, wherein the ultracapacitor takes on the highly-dynamic (transient) current demands, and the battery covers for steady-state loads. In order to avoid deep discharges of the ultracapacitor module, it is equipped with an auxiliary state-of-charge controller. Finally, for those applications where load is not measured, an adaptive Kalman filter-based load compensator is proposed and tested. The presented control strategy has been implemented on the low-cost industrial controller unit, and its effectiveness has been verified by means of simulations and experiments for the cases of abrupt load changes and quasi-stochastic load profiles using a downscaled battery/ultracapacitor hardware-in-the-loop experimental setup.

Energy storage for load leveling; Fuka heijunka ni kakasenai denryoku chozo

Energy Technology Data Exchange (ETDEWEB)

Morimoto, S. [Tokyo Electric Power Co. Inc., Tokyo (Japan)

1996-09-20

This paper introduces features and state of development of electric power storage technologies. Pumped storage power generation is a technology to store electric power by utilizing energy of position. However, because the plant locations are limited to mountainous areas far away from power demand areas, development of power storage technologies is being progressed from a new viewpoint of installing plants in the vicinity of demand areas. Superconduction power storage continues flowing current into a superconductor coil to store the power as electromagnetic energy, which is drawn out as electric power on request. Research and development is in progress in Japan on superconductor coils, permanent current switches, and control and protection systems. A flywheel system stores energy by rotating a disk at high speeds. Element technologies are being developed on long-period storage technologies such as superconductor magnetic bearings and high-speed rotating flywheels. For new load leveling batteries, development efforts are being given on sodium-sulfur batteries, zinc-bromine batteries, redox flow batteries, and lithium batteries. 3 refs., 1 fig., 2 tabs.

Influence of the control system on wind turbine loads during power production in extreme turbulence: Structural reliability

DEFF Research Database (Denmark)

Abdallah, Imad; Natarajan, Anand; Sørensen, John Dalsgaard

2016-01-01

structural reliability are assessed when the extreme turbulence model is uncertain. The structural reliability is assessed for the wind turbine when three configurations of an industrial grade load alleviation control system of increasing complexity and performance are used. The load alleviation features......The wind energy industry is continuously researching better computational models of wind inflow and turbulence to predict extreme loading (the nature of randomness) and their corresponding probability of occurrence. Sophisticated load alleviation control systems are increasingly being designed...... and deployed to specifically reduce the adverse effects of extreme load events resulting in lighter structures. The main objective herein is to show that despite large uncertainty in the extreme turbulence models, advanced load alleviation control systems yield both a reduction in magnitude and scatter...

A comparison of three observational techniques for assessing postural loads in industry.

Science.gov (United States)

Kee, Dohyung; Karwowski, Waldemar

2007-01-01

This study aims to compare 3 observational techniques for assessing postural load, namely, OWAS, RULA, and REBA. The comparison was based on the evaluation results generated by the classification techniques using 301 working postures. All postures were sampled from the iron and steel, electronics, automotive, and chemical industries, and a general hospital. While only about 21% of the 301 postures were classified at the action category/level 3 or 4 by both OWAS and REBA, about 56% of the postures were classified into action level 3 or 4 by RULA. The inter-method reliability for postural load category between OWAS and RULA was just 29.2%, and the reliability between RULA and REBA was 48.2%. These results showed that compared to RULA, OWAS, and REBA generally underestimated postural loads for the analyzed postures, irrespective of industry, work type, and whether or not the body postures were in a balanced state.

Energy-aware hybrid fruitfly optimization for load balancing in cloud environments for EHR applications

Directory of Open Access Journals (Sweden)

M. Lawanyashri

Full Text Available Cloud computing has gained precise attention from the research community and management of IT, due to its scalable and dynamic capabilities. It is evolving as a vibrant technology to modernize and restructure healthcare organization to provide best services to the consumers. The rising demand for healthcare services and applications in cloud computing leads to the imbalance in resource usage and drastically increases the power consumption resulting in high operating cost. To achieve fast execution time and optimum utilization of the virtual machines, we propose a multi-objective hybrid fruitfly optimization technique based on simulated annealing to improve the convergence rate and optimization accuracy. The proposed approach is used to achieve the optimal resource utilization and reduces the energy consumption and cost in cloud computing environment. The result attained in our proposed technique provides an improved solution. The experimental results show that the proposed algorithm efficiently outperforms compared to the existing load balancing algorithms. Keywords: Cloud computing, Electronic Health Records (EHR, Load balancing, Fruitfly Optimization Algorithm (FOA, Simulated Annealing (SA, Energy consumption

Recovery Act. Advanced Load Identification and Management for Buildings

Energy Technology Data Exchange (ETDEWEB)

Yang, Yi [Eaton Corporation, Menomonee Falls, WI (United States); Casey, Patrick [Eaton Corporation, Menomonee Falls, WI (United States); Du, Liang [Eaton Corporation, Menomonee Falls, WI (United States); He, Dawei [Eaton Corporation, Menomonee Falls, WI (United States)

2014-02-12

In response to the U.S. Department of Energy (DoE)’s goal of achieving market ready, net-zero energy residential and commercial buildings by 2020 and 2025, Eaton partnered with the Department of Energy’s National Renewable Energy Laboratory (NREL) and Georgia Institute of Technology to develop an intelligent load identification and management technology enabled by a novel “smart power strip” to provide critical intelligence and information to improve the capability and functionality of building load analysis and building power management systems. Buildings account for 41% of the energy consumption in the United States, significantly more than either transportation or industrial. Within the building sector, plug loads account for a significant portion of energy consumption. Plug load consumes 15-20% of building energy on average. As building managers implement aggressive energy conservation measures, the proportion of plug load energy can increase to as much as 50% of building energy leaving plug loads as the largest remaining single source of energy consumption. This project focused on addressing plug-in load control and management to further improve building energy efficiency accomplished through effective load identification. The execution of the project falls into the following three major aspects; An intelligent load modeling, identification and prediction technology was developed to automatically determine the type, energy consumption, power quality, operation status and performance status of plug-in loads, using electric waveforms at a power outlet level. This project demonstrated the effectiveness of the developed technology through a large set of plug-in loads measurements and testing; A novel “Smart Power Strip (SPS) / Receptacle” prototype was developed to act as a vehicle to demonstrate the feasibility of load identification technology as a low-cost, embedded solution; and Market environment for plug-in load control and management solutions

Energy potential of region and its quantitative assessment

Directory of Open Access Journals (Sweden)

Tatyana Aleksandrovna Kovalenko

2013-09-01

Full Text Available The purpose of the article is the development of the concept of the energy potential of the region (EPR, the analysis of the existing structure of relationships for the EPR elements in Ukraine and improvement of a quantitative assessment of energy potential of the region (country. The methods of an assessment of the existing condition of energy potential of the territory are the subject matter of the research. As a result of the analysis of concept’s definitions of energy potential of the region, it has further development and included the consumer potential of energy resources and capacity of management. The structure of relationships between elements of energy potential is developed for the Ukraine region. The new economic indicator — the realized energy potential is offered for an EPR assessment. By means of this indicator, the assessment of energy potential for the different countries of the world and a number of Ukraine areas of is performed.

Experimental assessment of the energy consumption of urban rail vehicles during stabling hours: Influence of ambient temperature

International Nuclear Information System (INIS)

Powell, J.P.; González-Gil, A.; Palacin, R.

2014-01-01

Urban rail has widely recognised potential to reduce congestion and air pollution in metropolitan areas, given its high capacity and environmental performance. Nevertheless, growing capacity demands and rising energy costs may call for significant energy efficiency improvements in such systems. Energy consumed by stabled rolling stock has been traditionally overlooked in the scientific literature in favour of analysing traction loads, which generally account for the largest share of this consumption. Thus, this paper presents the methodology and results of an experimental investigation that aimed to assess the energy use of stabled vehicles in the Tyne and Wear Metro system (UK). It is revealed that approximately 11% of the rolling stock's total energy consumption is due to the operation of on-board auxiliaries when stabled, and investigation of these loads is therefore a worthwhile exercise. Heating is responsible for the greatest portion of this energy, and an empirical correlation between ambient temperature and power drawn is given. This could prove useful for a preliminary evaluation of further energy saving measures in this area. Even though this investigation focused on a particular metro system in a relatively cold region, its methodology may also be valid for other urban and main line railways operating in different climate conditions. - Highlights: •Energy use of stabled vehicles in an actual metro system is experimentally examined. •Stabling hours account for about 11% of the vehicles' total energy consumption. •Heating is the major consumer during stabling hours. •An empirical correlation between ambient temperature and power drawn is derived. •The methodology described may also be applied to other urban and main line railways

Energy options for residential buildings assessment

International Nuclear Information System (INIS)

Rezaie, Behnaz; Dincer, Ibrahim; Esmailzadeh, Ebrahim

2013-01-01

Highlights: ► Studying various building energy options. ► Assessing these options from various points. ► Comparing these options for better environment and sustainability. ► Proposing renewable energy options as potential solutions. - Abstract: The building sector, as one of the major energy consumers, demands most of the energy research to assess different energy options from various aspects. In this paper, two similar residential buildings, with either low or high energy consumption patterns, are chosen as case studies. For these case studies, three different renewable energy technology and three different hybrid systems are designed for a specified size. Then, the environmental impact indices, renewable energy indices, and the renewable exergy indices have been estimated for every energy options. Results obtained show that the hybrid systems (without considering the economics factors) are superior and having top indices. The importance of the energy consumption patterns in buildings are proven by the indices. By cutting the energy consumption to about 40% the environment index would increase by more than twice (2.1). Utilization of the non-fossil fuels is one part of the solution to environmental problems while energy conservation being the other. It has been shown that the re-design of the energy consumption model is less complex but more achievable for buildings.

Do 'enabling technologies' affect customer performance in price-responsive load programs?

International Nuclear Information System (INIS)

Goldman, Charles A.; Kintner-Meyer, Michael; Heffner, Grayson

2002-01-01

Price-responsive load (PRL) programs vary significantly in overall design, the complexity of relationships between program administrators, load aggregators, and customers, and the availability of ''enabling technologies''. Enabling technologies include such features as web-based power system and price monitoring, control and dispatch of curtailable loads, communications and information systems links to program participants, availability of interval metering data to customers in near real time, and building/facility/end-use automation and management capabilities. Two state agencies - NYSERDA in New York and the CEC in California - have been conspicuous leaders in the demonstration of demand response (DR) programs utilizing enabling technologies. In partnership with key stakeholders in these two states (e.g., grid operator, state energy agencies, and program administrators), Lawrence Berkeley National Laboratory (LBNL) and Pacific Northwest National Laboratory (PNNL) surveyed 56 customers who worked with five contractors participating in CEC or NYSERDA-sponsored DR programs. We combined market research and actual load curtailment data when available (i.e., New York) or customer load reduction targets in order to explore the relative importance of contractor's program design features, sophistication of control strategies, and reliance on enabling technologies in predicting customer's ability to deliver load reductions in DR programs targeted to large commercial/industrial customers. We found preliminary evidence that DR enabling technology has a positive effect on load curtailment potential. Many customers indicated that web-based energy information tools were useful for facilitating demand response (e.g., assessing actual performance compared to load reduction contract commitments), that multiple notification channels facilitated timely response, and that support for and use of backup generation allowed customers to achieve significant and predictable load

An enviro-economic function for assessing energy resources for district energy systems

International Nuclear Information System (INIS)

Rezaie, Behnaz; Reddy, Bale V.; Rosen, Marc A.

2014-01-01

District energy (DE) systems provide an important means of mitigating greenhouse gas emissions and the significant related concerns associated with global climate change. DE systems can use fossil fuels, renewable energy and waste heat as energy sources, and facilitate intelligent integration of energy systems. In this study, an enviro-economic function is developed for assessing various energy sources for a district energy system. The DE system is assessed for the considered energy resources by considering two main factors: CO 2 emissions and economics. Using renewable energy resources and associated technologies as the energy suppliers for a DE system yields environmental benefits which can lead to financial advantages through such instruments as tax breaks; while fossil fuels are increasingly penalized by a carbon tax. Considering these factors as well as the financial value of the technology, an analysis approach is developed for energy suppliers of the DE system. In addition, the proposed approach is modified for the case when thermal energy storage is integrated into a DE system. - Highlights: • Developed a function to assess various energy sources for a district energy system. • Considered CO 2 emissions and economics as two main factors. • Applied renewable energy resources technologies as the suppliers for a DE system. • Yields environmental benefits can lead to financial benefits by tax breaks. • Modified enviro-economic function for the TES integrated into a DE system

Distribution load estimation - DLE

Energy Technology Data Exchange (ETDEWEB)

Seppaelae, A. [VTT Energy, Espoo (Finland)

1996-12-31

The load research project has produced statistical information in the form of load models to convert the figures of annual energy consumption to hourly load values. The reliability of load models is limited to a certain network because many local circumstances are different from utility to utility and time to time. Therefore there is a need to make improvements in the load models. Distribution load estimation (DLE) is the method developed here to improve load estimates from the load models. The method is also quite cheap to apply as it utilises information that is already available in SCADA systems

Distribution load estimation - DLE

Energy Technology Data Exchange (ETDEWEB)

Seppaelae, A [VTT Energy, Espoo (Finland)

1997-12-31

The load research project has produced statistical information in the form of load models to convert the figures of annual energy consumption to hourly load values. The reliability of load models is limited to a certain network because many local circumstances are different from utility to utility and time to time. Therefore there is a need to make improvements in the load models. Distribution load estimation (DLE) is the method developed here to improve load estimates from the load models. The method is also quite cheap to apply as it utilises information that is already available in SCADA systems

Particle loading rates for HVAC filters, heat exchangers, and ducts.

Science.gov (United States)

Waring, M S; Siegel, J A

2008-06-01

The rate at which airborne particulate matter deposits onto heating, ventilation, and air-conditioning (HVAC) components is important from both indoor air quality (IAQ) and energy perspectives. This modeling study predicts size-resolved particle mass loading rates for residential and commercial filters, heat exchangers (i.e. coils), and supply and return ducts. A parametric analysis evaluated the impact of different outdoor particle distributions, indoor emission sources, HVAC airflows, filtration efficiencies, coils, and duct system complexities. The median predicted residential and commercial loading rates were 2.97 and 130 g/m(2) month for the filter loading rates, 0.756 and 4.35 g/m(2) month for the coil loading rates, 0.0051 and 1.00 g/month for the supply duct loading rates, and 0.262 g/month for the commercial return duct loading rates. Loading rates are more dependent on outdoor particle distributions, indoor sources, HVAC operation strategy, and filtration than other considered parameters. The results presented herein, once validated, can be used to estimate filter changing and coil cleaning schedules, energy implications of filter and coil loading, and IAQ impacts associated with deposited particles. The results in this paper suggest important factors that lead to particle deposition on HVAC components in residential and commercial buildings. This knowledge informs the development and comparison of control strategies to limit particle deposition. The predicted mass loading rates allow for the assessment of pressure drop and indoor air quality consequences that result from particle mass loading onto HVAC system components.

"Watts per person" paradigm to design net zero energy buildings: Examining technology interventions and integrating occupant feedback to reduce plug loads in a commercial building

Science.gov (United States)

Yagi Kim, Mika

As building envelopes have improved due to more restrictive energy codes, internal loads have increased largely due to the proliferation of computers, electronics, appliances, imaging and audio visual equipment that continues to grow in commercial buildings. As the dependency on the internet for information and data transfer increases, the electricity demand will pose a challenge to design and operate Net Zero Energy Buildings (NZEBs). Plug Loads (PLs) as a proportion of the building load has become the largest non-regulated building energy load and represents the third highest electricity end-use in California's commercial office buildings, accounting for 23% of the total building electricity consumption (Ecova 2011,2). In the Annual Energy Outlook 2008 (AEO2008), prepared by the Energy Information Administration (EIA) that presents long-term projections of energy supply and demand through 2030 states that office equipment and personal computers are the "fastest growing electrical end uses" in the commercial sector. This thesis entitled "Watts Per Person" Paradigm to Design Net Zero Energy Buildings, measures the implementation of advanced controls and behavioral interventions to study the reduction of PL energy use in the commercial sector. By integrating real world data extracted from an energy efficient commercial building of its energy use, the results produce a new methodology on estimating PL energy use by calculating based on "Watts Per Person" and analyzes computational simulation methods to design NZEBs.

ASSESSMENT OF CLIMATE CHANGE IMPACT ON THE REQUIRED COOLING LOAD OF THE HOSPITAL BUILDINGS

Directory of Open Access Journals (Sweden)

M. AHMADZADEHTALATAPEH

2017-08-01

Full Text Available The impact of climate change on the energy performance of the Heating, Ventilation and Air Conditioning (HVAC systems was studied in this research. The present research employs the Transient System Simulation Software (TRNSYS to study the hour-by-hour influence of the climate change scenario on a HVAC system performance by modeling the system in the TRNSYS software as the base line model. To this end, a HVAC system operating in a hospital as a high energy demanding building was selected for data collection, analysis and simulation. Three sets of predicted Typical Meteorological Year (TMY data for the region are used for simulation in the TRNSYS to analyze the established indoor air conditions and yearly required cooling loads by the building. Based on the predictions and comparison of the findings with the year 2000, it can be estimated that the yearly required cooling load for 2020 and 2050 would be increased by 4.66% and 7.3%, respectively.

Industrial wastewater treatment with a bioelectrochemical process: assessment of depuration efficiency and energy production.

Science.gov (United States)

Molognoni, Daniele; Chiarolla, Stefania; Cecconet, Daniele; Callegari, Arianna; Capodaglio, Andrea G

2018-01-01

Development of renewable energy sources, efficient industrial processes, energy/chemicals recovery from wastes are research issues that are quite contemporary. Bioelectrochemical processes represent an eco-innovative technology for energy and resources recovery from both domestic and industrial wastewaters. The current study was conducted to: (i) assess bioelectrochemical treatability of industrial (dairy) wastewater by microbial fuel cells (MFCs); (ii) determine the effects of the applied organic loading rate (OLR) on MFC performance; (iii) identify factors responsible for reactor energy recovery losses (i.e. overpotentials). For this purpose, an MFC was built and continuously operated for 72 days, during which the anodic chamber was fed with dairy wastewater and the cathodic chamber with an aerated mineral solution. The study demonstrated that industrial effluents from agrifood facilities can be treated by bioelectrochemical systems (BESs) with >85% (average) organic matter removal, recovering power at an observed maximum density of 27 W m -3 . Outcomes were better than in previous (shorter) analogous experiences, and demonstrate that this type of process could be successfully used for dairy wastewater with several advantages.

Solar energy: a UK assessment

Energy Technology Data Exchange (ETDEWEB)

1976-01-01

A panel convened by UK-ISES to analyze all aspects of solar energy systems and to assess the potential for solar energy utilization and research and development needs in the UK and for export is reported. Topics covered include: solar energy in relation to other energy sources; international solar energy research and development program; the physical nature of solar energy and its availability in the UK and other countries; thermal collection, storage, and low-temperature applications; solar energy and architecture; solar thermal power systems; solar cells; agricultural and biological systems; photochemical systems; social, legal, and political considerations with particular reference to the UK; and future policy on solar research and development for the UK. (WDM)

Balancing the Power-to-Load Ratio for a Novel Variable Geometry Wave Energy Converter with Nonideal Power Take-Off in Regular Waves: Preprint

Energy Technology Data Exchange (ETDEWEB)

Tom, Nathan M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Yu, Yi-Hsiang [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Wright, Alan D [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2017-09-28

This work attempts to balance power absorption against structural loading for a novel variable geometry wave energy converter. The variable geometry consists of four identical flaps that will be opened in ascending order starting with the flap closest to the seafloor and moving to the free surface. The influence of a pitch motion constraint on power absorption when utilizing a nonideal power take-off (PTO) is examined and found to reduce the losses associated with bidirectional energy flow. The power-to-load ratio is evaluated using pseudo-spectral control to determine the optimum PTO torque based on a multiterm objective function. The pseudo-spectral optimal control problem is extended to include load metrics in the objective function, which may now consist of competing terms. Separate penalty weights are attached to the surge-foundation force and PTO control torque to tune the optimizer performance to emphasize either power absorption or load shedding. PTO efficiency is not included in the objective function, but the penalty weights are utilized to limit the force and torque amplitudes, thereby reducing losses associated with bidirectional energy flow. Results from pseudo-spectral control demonstrate that shedding a portion of the available wave energy can provide greater reductions in structural loads and reactive power.

Assessing reliability in energy supply systems

International Nuclear Information System (INIS)

McCarthy, Ryan W.; Ogden, Joan M.; Sperling, Daniel

2007-01-01

Reliability has always been a concern in the energy sector, but concerns are escalating as energy demand increases and the political stability of many energy supply regions becomes more questionable. But how does one define and measure reliability? We introduce a method to assess reliability in energy supply systems in terms of adequacy and security. It derives from reliability assessment frameworks developed for the electricity sector, which are extended to include qualitative considerations and to be applicable to new energy systems by incorporating decision-making processes based on expert opinion and multi-attribute utility theory. The method presented here is flexible and can be applied to any energy system. To illustrate its use, we apply the method to two hydrogen pathways: (1) centralized steam reforming of imported liquefied natural gas with pipeline distribution of hydrogen, and (2) on-site electrolysis of water using renewable electricity produced independently from the electricity grid

Methods of Comprehensive Assessment for China’s Energy Sustainability

Science.gov (United States)

Xu, Zhijin; Song, Yankui

2018-02-01

In order to assess the sustainable development of China’s energy objectively and accurately, we need to establish a reasonable indicator system for energy sustainability and make a targeted comprehensive assessment with the scientific methods. This paper constructs a comprehensive indicator system for energy sustainability from five aspects of economy, society, environment, energy resources and energy technology based on the theory of sustainable development and the theory of symbiosis. On this basis, it establishes and discusses the assessment models and the general assessment methods for energy sustainability with the help of fuzzy mathematics. It is of some reference for promoting the sustainable development of China’s energy, economy and society.

Research into the Energy Output of Asymmetric Cylindrical Structure under Internal Explosion Loading

Directory of Open Access Journals (Sweden)

Liangliang Ding

2018-04-01

Full Text Available The energy output characteristic of an asymmetric cylindrical structure under internal explosion loading has significant research value in the field of the national defense industry. This paper took the D-shaped structure as the research object. Three groups of experiments (D-90°, D-120°, D-150° were carried out. The D-shaped structure showed that fragments are concentrated in the middle and are sparse on both sides. Moreover, the fragment density decreased with the increase of the azimuth angle. The fragment velocities, which were measured from high-speed photography and an oscilloscope, coincided well with each other, and decreased with an increase in the central angle. Compared with the cylindrical structure, the fragment energy gain of the D-shaped structure is significant; the total energy and energy density of the three D-shaped structures were very close to each other. This indicates that D-120° is the optimal solution among the three D-shaped structures and it can provide guidance for the future design of D-shaped structures to achieve higher energy output.

Energy and exergy assessments for an enhanced use of energy in buildings

Science.gov (United States)

Goncalves, Pedro Manuel Ferreira

Exergy analysis has been found to be a useful method for improving the conversion efficiency of energy resources, since it helps to identify locations, types and true magnitudes of wastes and losses. It has also been applied for other purposes, such as distinguishing high- from low-quality energy sources or defining the engineering technological limits in designing more energy-efficient systems. In this doctoral thesis, the exergy analysis is widely applied in order to highlight and demonstrate it as a significant method of performing energy assessments of buildings and related energy supply systems. It aims to make the concept more familiar and accessible for building professionals and to encourage its wider use in engineering practice. Case study I aims to show the importance of exergy analysis in the energy performance assessment of eight space heating building options evaluated under different outdoor environmental conditions. This study is concerned with the so-called "reference state", which in this study is calculated using the average outdoor temperature for a given period of analysis. Primary energy and related exergy ratios are assessed and compared. Higher primary exergy ratios are obtained for low outdoor temperatures, while the primary energy ratios are assumed as constant for the same scenarios. The outcomes of this study demonstrate the significance of exergy analysis in comparison with energy analysis when different reference states are compared. Case study II and Case study III present two energy and exergy assessment studies applied to a hotel and a student accommodation building, respectively. Case study II compares the energy and exergy performance of the main end uses of a hotel building located in Coimbra in central Portugal, using data derived from an energy audit. Case study III uses data collected from energy utilities bills to estimate the energy and exergy performance associated to each building end use. Additionally, a set of energy

Assessment of a closed thermochemical energy storage using energy and exergy methods

International Nuclear Information System (INIS)

Abedin, Ali Haji; Rosen, Marc A.

2012-01-01

Highlights: ► Thermodynamics assessments are reported for a general closed thermochemical thermal energy storage system. ► Energy and exergy efficiencies of various processes in a closed thermochemical TES are evaluated and compared. ► Understanding is enhanced of thermochemical TES technologies and their potential implementations. ► Exergy analysis is observed to be useful when applied to thermochemical TES, with or in place of energy analysis. - Abstract: Thermal energy storage (TES) is an important technology for achieving more efficient and environmentally benign energy systems. Thermochemical TES is a type of TES with the potential for high energy density and is only recently being considered intensively. To improve understanding of thermochemical TES systems and their implementation, energy and exergy analyses are beneficial. Here, thermodynamics assessments are presented for a general closed thermochemical TES system, including assessments and comparisons of the efficiencies of the overall thermochemical TES cycle and its charging, storing and discharging processes. Locations and causes of thermodynamic losses in thermochemical TES systems are being specified using exergy analysis. The analytical methodology applied in this study identifies that energy and exergy efficiencies differ for thermochemical TESs, e.g. the energy efficiency for a case study is approximately 50% while the exergy efficiency is about 10%. Although the focus is to evaluate thermodynamic efficiencies, other design parameters such as cost, and environmental impact also need to be examined in assessing thermochemical storage. The efficiencies for thermochemical TES provided here should be helpful for designing these energy systems and enhancing their future prospects.

Latching and Declutching Control of the Solo Duck Wave-Energy Converter with Different Load Types

Directory of Open Access Journals (Sweden)

Jinming Wu

2017-12-01

Full Text Available The solo duck wave-energy converter (WEC captures power in a point absorber manner, hence it exhibits high power-capture efficiency within only a narrow bandwidth. Passive control is characterized by a unidirectional power flow, and thus its engineering implementation can be simplified. In this paper, two typical passive control strategies, latching and declutching control, are applied to the solo duck WEC to improve its power-capture performance at wave periods larger and smaller than the natural period of the WEC, respectively. Special attention is paid to the peak value of instantaneous WEC performance parameters, including the peak motion excursion, the peak power take-off (PTO moment, and the peak-to-average power ratio, when the captured power is maximized. Performance differences between the linear and coulomb loads are also investigated. Results show that both latching and declutching control can effectively improve captured power, but also incidentally increase the peak motion excursion and peak-to-average power ratio. When under latching and declutching control, the coulomb load leads to the same maximum relative capture width and peak motion excursion as the linear load, but presents smaller peak PTO moment and peak-to-average power ratio than the linear load, hence making the coulomb load the better choice for the solo duck WEC.

NCAP test improvements with pretensioners and load limiters.

Science.gov (United States)

Walz, Marie

2004-03-01

New Car Assessment Program (NCAP) test scores, measured by the United States Department of Transportation's (USDOT) National Highway Traffic Safety Administration (NHTSA), were analyzed in order to assess the benefits of equipping safety belt systems with pretensioners and load limiters. Safety belt pretensioners retract the safety belt almost instantly in a crash to remove excess slack. They tie the occupant to the vehicle's deceleration early during the crash, reducing the peak load experienced by the occupant. Load limiters and other energy management systems allow safety belts to yield in a crash, preventing the shoulder belt from directing too much energy on the chest of the occupant. In NCAP tests, vehicles are crashed into a fixed barrier at 35 mph. During the test, instruments measure the accelerations of the head and chest, as well as the force on the legs of anthropomorphic dummies secured in the vehicle by safety belts. NCAP data from model year 1998 through 2001 cars and light trucks were examined. The combination of pretensioners and load limiters is estimated to reduce Head Injury Criterion (HIC) by 232, chest acceleration by an average of 6.6 g's, and chest deflection (displacement) by 10.6 mm, for drivers and right front passengers. The unit used to measure chest acceleration (g) is defined as a unit of force equal to the force exerted by gravity. All of these reductions are statistically significant. When looked at individually, pretensioners are more effective in reducing HIC scores for both drivers and right front passengers, as well as chest acceleration and chest deflection scores for drivers. Load limiters show greater reductions in chest acceleration and chest deflection scores for right front passengers. By contrast, in make-models for which neither load limiters nor pretensioners have been added, there is little change during 1998 to 2001 in HIC, chest acceleration, or chest deflection values in NCAP tests.

An assessement of global energy resource economic potentials

International Nuclear Information System (INIS)

Mercure, Jean-François; Salas, Pablo

2012-01-01

This paper presents an assessment of global economic energy potentials for all major natural energy resources. This work is based on both an extensive literature review and calculations using natural resource assessment data. Economic potentials are presented in the form of cost-supply curves, in terms of energy flows for renewable energy sources, or fixed amounts for fossil and nuclear resources, with strong emphasis on uncertainty, using a consistent methodology that allow direct comparisons to be made. In order to interpolate through available resource assessment data and associated uncertainty, a theoretical framework and a computational methodology are given based on statistical properties of different types of resources, justified empirically by the data, and used throughout. This work aims to provide a global database for natural energy resources ready to integrate into models of energy systems, enabling to introduce at the same time uncertainty over natural resource assessments. The supplementary material provides theoretical details and tables of data and parameters that enable this extensive database to be adapted to a variety of energy systems modelling frameworks. -- Highlights: ► Global energy potentials for all major energy resources are reported. ► Theory and methodology for calculating economic energy potentials is given. ► An uncertainty analysis for all energy economic potentials is carried out.

78 FR 13874 - Watershed Modeling To Assess the Sensitivity of Streamflow, Nutrient, and Sediment Loads to...

Science.gov (United States)

2013-03-01

... EPA's policy to include all comments it receives in the public docket without change and to make the... Modeling To Assess the Sensitivity of Streamflow, Nutrient, and Sediment Loads to Climate Change and Urban... Loads to Climate Change and Urban Development in 20 U.S. Watersheds (EPA/600/R-12/058). EPA also is...

Chapter 2: Assessing the Potential Energy Impacts of Clean Energy Initiatives

Science.gov (United States)

Chapter 2 of Assessing the Multiple Benefits of Clean Energy helps state energy, environmental, and economic policy makers identify and quantify the many benefits of clean energy to support the development and implementation of cost-effective clean energ

Prospects of Appliance-Level Load Monitoring in Off-the-Shelf Energy Monitors: A Technical Review

Directory of Open Access Journals (Sweden)

Anwar Ul Haq

2018-01-01

Full Text Available The smart grid initiative has encouraged utility companies worldwide to roll-out new and smarter versions of energy meters. Before an extensive roll-out, which is both labor-intensive and incurs high capital costs, consumers need to be incentivised to reap the long-term benefits of such smart meters. Off-the-shelf energy monitors (e-monitors can provide consumers with an insight into such potential benefits. As e-monitors are owned by the consumer, the consumer has greater control over the data, which significantly reduces the privacy and data confidentiality concerns. Because only limited online technical information is available about e-monitors, we evaluate several existing e-monitors using an online technical survey directly from the vendors. Besides automated e-monitoring, the use of different off-the-shelf e-monitors can also help to demonstrate state-of-the-art techniques such as non-intrusive load monitoring (NILM, data analytics, and the predictive maintenance of appliances. Our survey indicates a trend towards the incorporation of such state-of-the-art capabilities, particularly the appliance-level e-monitoring and load disaggregation. We have also discussed some essential requirements to implement load disaggregation in the next generation e-monitors. In future, these intelligent e-monitoring techniques will encourage effective consumer participation in the demand-side management (DSM programs.

Trade-offs in assessing different energy futures: a regional multi-criteria assessment of the role of carbon dioxide capture and storage

International Nuclear Information System (INIS)

Shackley, Simon; McLachlan, Carly

2006-01-01

We examine the responses of stakeholders from the public and private sectors to future energy scenarios for the year 2050 for the North West of England. The main focus of the paper is to examine the stakeholders' reactions to the mitigation option of capturing CO 2 from power stations and storing it in suitable off-shore geological reservoirs. Five energy scenarios were developed which involved a range of levels of CO 2 capture and storage (CCS): Fossilwise, Nuclear Renaissance, Renewable Generation and Spreading the Load high and low scenarios. A multi-criteria assessment method (MCA) was used as a way of elucidating stakeholders' views on the desirability or otherwise of each scenario against nine stakeholder-derived criteria. We found that stakeholders were either business-focused or environment/society-focused with respect to weighting of the criteria. Scoring of the scenarios did not follow such a straightforward pattern. Most respondents scored and weighted strategically and tended to express a clear preference for a form of energy generation. The results suggest that there is unlikely to be a wide-ranging consensus amongst energy stakeholders on the desirability of specific future forms of energy generation. On balance, the results support the inclusion of CCS within scenarios of a low-carbon energy system

Large Hybrid Energy Systems for Making Low CO2 Load-Following Power and Synthetic Fuel

International Nuclear Information System (INIS)

Cherry, Robert S.; Boardman, Richard D.; Aumeier, Steven

2012-01-01

Hybrid energy systems using nuclear heat sources can economically produce load-following electrical power by exploiting the surplus generation capacity available at night or seasonally to make synthetic fuel. Vehicle fuel is the only current energy use large enough to absorb all the energy capacity that might be diverted from the power industry, and its ease of storage obviates problems with discontinuous synfuel production. The potential benefits and challenges of synfuels integration are illustrated by the production of methanol from natural gas (as a source of carbon) using steam from a light water nuclear power reactor which is assumed to be available in accord with a year's worth of power demand data. Methanol's synthesis process is easily adapted to using 300 C heat from a light water reactor and this simple compound can be further processed into gasoline, biodiesel, or dimethyl ether, fuels which can be used with the current vehicle fleet. A supplemental feed to the methanol process of natural gas (for energy) allows operation at constant full rate when the nuclear heat is being used to produce electrical power. The higher capital costs of such a system are offset by a lower cost of heat and power production from a large base load type of plant and by reduced costs associated with much lower CO2 emissions. Other less tangible economic benefits of this and similar hybrid systems include better use of natural resource for fuels and greater energy services security from the domestic production of vehicle fuel.

Fracture assessment of HSST Plate 14 shallow-flaw cruciform bend specimens tested under biaxial loading conditions

Energy Technology Data Exchange (ETDEWEB)

Bass, B.R.; McAfee, W.J.; Williams, P.T.; Pennell, W.E.

1998-06-01

A technology to determine shallow-flaw fracture toughness of reactor pressure vessel (RPV) steels is being developed for application to the safety assessment of RPVs containing postulated shallow surface flaws. Matrices of cruciform beam tests were developed to investigate and quantify the effects of temperature, biaxial loading, and specimen size on fracture initiation toughness of two-dimensional (constant depth), shallow, surface flaws. The cruciform beam specimens were developed at Oak Ridge National Laboratory (ORNL) to introduce a far-field, out-of-plane biaxial stress component in the test section that approximates the nonlinear stresses resulting from pressurized-thermal-shock or pressure-temperature loading of an RPV. Tests were conducted under biaxial load ratios ranging from uniaxial to equibiaxial. These tests demonstrated that biaxial loading can have a pronounced effect on shallow-flaw fracture toughness in the lower transition temperature region for an RPV material. The cruciform fracture toughness data were used to evaluate fracture methodologies for predicting the observed effects of biaxial loading on shallow-flaw fracture toughness. Initial emphasis was placed on assessment of stress-based methodologies, namely, the J-Q formulation, the Dodds-Anderson toughness scaling model, and the Weibull approach. Applications of these methodologies based on the hydrostatic stress fracture criterion indicated an effect of loading-biaxiality on fracture toughness; the conventional maximum principal stress criterion indicated no effect. A three-parameter Weibull model based on the hydrostatic stress criterion is shown to correlate the experimentally observed biaxial effect on cleavage fracture toughness by providing a scaling mechanism between uniaxial and biaxial loading states.

Improving Sensitivity to Detect Mild Cognitive Impairment: Cognitive Load Dual-Task Gait Speed Assessment.

Science.gov (United States)

MacAulay, Rebecca K; Wagner, Mark T; Szeles, Dana; Milano, Nicholas J

2017-07-01

Longitudinal research indicates that cognitive load dual-task gait assessment is predictive of cognitive decline and thus might provide a sensitive measure to screen for mild cognitive impairment (MCI). However, research among older adults being clinically evaluated for cognitive concerns, a defining feature of MCI, is lacking. The present study investigated the effect of performing a cognitive task on normal walking speed in patients presenting to a memory clinic with cognitive complaints. Sixty-one patients with a mean age of 68 years underwent comprehensive neuropsychological testing, clinical interview, and gait speed (simple- and dual-task conditions) assessments. Thirty-four of the 61 patients met criteria for MCI. Repeated measure analyses of covariance revealed that greater age and MCI both significantly associated with slower gait speed, pscognitive dual task within a clinically representative population. Cognitive load dual-task gait assessment may provide a cost efficient and sensitive measure to detect older adults at high risk of a dementia disorder. (JINS, 2017, 23, 493-501).

Electricity Crisis and Load Management in Bangladesh

Directory of Open Access Journals (Sweden)

Rajib Kanti Das

2012-09-01

Full Text Available Bangladesh is a densely populated country. Only a small part of her area is electrified which cover around 18% of total population. The people who are in the electrified area are suffering from severe load shedding. A systematic load management procedure related to demand side may improve the situation is the research problem. The major objectives serve by the research are to analyze contemporary electricity status with a view to drawing inference about demand supply gap and extracting benefits from load management. Data supplied by the Bangladesh Power Development Board, World Bank and outcome of survey are analyzed with some simple statistical tools to test the hypothesis. Analysis discloses that with properly managed uses of electricity with load switch and rotation week-end can improve the concurrent condition of electricity. Moreover, introducing smart distribution system, reducing system loss, shifting load to off-peak, large scale use of prepaid mete, observing energy week and using energy efficient home and office appliance are recommended to improve load through demand side management. Some other recommendations such as introducing alternative energy, public private partnership and using renewable energy development and producing energy locally are made for load management from the supply side.

Development of the advanced load leveling air conditioning technology utilizing unutilized energy; Miriyo energy kodo katsuyo fuka heijunka reidanbo gijutsu no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-03-01

A heat supply plant utilizing unutilized energy is called for environment-friendly efficient operation including stable heat supply, energy saving, CO{sub 2} emission control and power load leveling. Toshiba developed the optimum operation system for environment-friendly efficient operation considering heat demand prediction and characteristics of a heat supply plant. The demonstration test result showed that this system is effective to reduce power cost of a heat supply plant by nearly 15%. This system was promoted by joint research of NEDO, Heat Pump and Thermal Storage Technology Center of Japan and Toshiba supported by Agency of Natural Resources and Energy, MITI. (translated by NEDO)

Offshore Resource Assessment and Design Conditions: A Data Requirements and Gaps Analysis for Offshore Renewable Energy Systems

Energy Technology Data Exchange (ETDEWEB)

Elliott, Dennis [National Renewable Energy Lab. (NREL), Golden, CO (United States); Frame, Caitlin [National Oceanic and Atmospheric Administration (NOAA), Washington, DC (United States); Gill, Carrie [National Oceanic and Atmospheric Administration (NOAA), Washington, DC (United States); Hanson, Howard [Florida Atlantic Univ., Boca Raton, FL (United States); Moriarty, Patrick [National Renewable Energy Lab. (NREL), Golden, CO (United States); Powell, Mark [National Oceanic and Atmospheric Administration (NOAA), Washington, DC (United States); Shaw, William J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wilczak, Jim [National Oceanic and Atmospheric Administration (NOAA), Washington, DC (United States); Wynne, Jason [Energetics, Columbia, MD (United States)

2012-03-01

The offshore renewable energy industry requires accurate meteorological and oceanographic (“metocean”) data for evaluating the energy potential, economic viability, and engineering requirements of offshore renewable energy projects. It is generally recognized that currently available metocean data, instrumentation, and models are not adequate to meet all of the stakeholder needs on a national scale. Conducting wind and wave resource assessments and establishing load design conditions requires both interagency collaboration as well as valuable input from experts in industry and academia. Under the Department of Energy and Department of Interior Memorandum of Understanding, the Resource Assessment and Design Condition initiative supports collaborative national efforts by adding to core atmospheric and marine science knowledge relevant to offshore energy development. Such efforts include a more thorough understanding and data collection of key metocean phenomena such as wind velocity and shear; low-level jets; ocean, tidal, and current velocities; wave characteristics; geotechnical data relating to surface and subsurface characteristics; seasonal and diurnal variations; and the interaction among these conditions. Figure 1 presents a graphical representation of some metocean phenomena that can impact offshore energy systems. This document outlines the metocean observations currently available; those that are not available; and those that require additional temporal-spatial coverage, resolution, or processing for offshore energy in an effort to gather agreed-upon, needed observations.

Advances in the Assessment of Wind Turbine Operating Extreme Loads via More Efficient Calculation Approaches

Energy Technology Data Exchange (ETDEWEB)

Graf, Peter; Damiani, Rick R.; Dykes, Katherine; Jonkman, Jason M.

2017-01-09

A new adaptive stratified importance sampling (ASIS) method is proposed as an alternative approach for the calculation of the 50 year extreme load under operational conditions, as in design load case 1.1 of the the International Electrotechnical Commission design standard. ASIS combines elements of the binning and extrapolation technique, currently described by the standard, and of the importance sampling (IS) method to estimate load probability of exceedances (POEs). Whereas a Monte Carlo (MC) approach would lead to the sought level of POE with a daunting number of simulations, IS-based techniques are promising as they target the sampling of the input parameters on the parts of the distributions that are most responsible for the extreme loads, thus reducing the number of runs required. We compared the various methods on select load channels as output from FAST, an aero-hydro-servo-elastic tool for the design and analysis of wind turbines developed by the National Renewable Energy Laboratory (NREL). Our newly devised method, although still in its infancy in terms of tuning of the subparameters, is comparable to the others in terms of load estimation and its variance versus computational cost, and offers great promise going forward due to the incorporation of adaptivity into the already powerful importance sampling concept.

Distribution load estimation (DLE)

Energy Technology Data Exchange (ETDEWEB)

Seppaelae, A; Lehtonen, M [VTT Energy, Espoo (Finland)

1998-08-01

The load research has produced customer class load models to convert the customers` annual energy consumption to hourly load values. The reliability of load models applied from a nation-wide sample is limited in any specific network because many local circumstances are different from utility to utility and time to time. Therefore there is a need to find improvements to the load models or, in general, improvements to the load estimates. In Distribution Load Estimation (DLE) the measurements from the network are utilized to improve the customer class load models. The results of DLE will be new load models that better correspond to the loading of the distribution network but are still close to the original load models obtained by load research. The principal data flow of DLE is presented

Battery energy storage systems: Assessment for small-scale renewable energy integration

Energy Technology Data Exchange (ETDEWEB)

Nair, Nirmal-Kumar C.; Garimella, Niraj [Power Systems Group, Department of Electrical and Computer Engineering, The University of Auckland, 38 Princes Street, Science Centre, Auckland 1142 (New Zealand)

2010-11-15

Concerns arising due to the variability and intermittency of renewable energy sources while integrating with the power grid can be mitigated to an extent by incorporating a storage element within the renewable energy harnessing system. Thus, battery energy storage systems (BESS) are likely to have a significant impact in the small-scale integration of renewable energy sources into commercial building and residential dwelling. These storage technologies not only enable improvements in consumption levels from renewable energy sources but also provide a range of technical and monetary benefits. This paper provides a modelling framework to be able to quantify the associated benefits of renewable resource integration followed by an overview of various small-scale energy storage technologies. A simple, practical and comprehensive assessment of battery energy storage technologies for small-scale renewable applications based on their technical merit and economic feasibility is presented. Software such as Simulink and HOMER provides the platforms for technical and economic assessments of the battery technologies respectively. (author)

Assessment of load of beam-balanced pumping units by electric motor power indicators

Directory of Open Access Journals (Sweden)

Д. И. Шишлянников

2017-10-01

Full Text Available The results of experimental studies on the loading of beam-balanced pumping units (BP of sucker rod- pumping equipment (SRPE are presented. It is noted that the key factor that has the most significant effect causing the SRPE failure is the balance of the beam pumping unit, which determines the amount of specific energy consumption for the rise of reservoir fluid and the level of dynamic loads on the machine units. The urgency of using software-recording systems for estimating the loading of units of oil field pumping installations is substantiated. The principle of operation and design of the «AKD-SK» software recording system is described. The prospects of using this method for controlling the performance parameters and evaluating the technical state of the sicker rod-pumping units is proved on the basis of an analysis of the magnitude and nature of the changes in the loads of drive motors determined by the registration of the instantaneous values of the consumed power. The main provisions of the methodology for analyzing the watt-meters of drive motors of the sucker rod-pumping units are outlined. The nature of the manifestation of the main defects of submersible pumps and beam-balanced pumping units is described. The results of pilot-industrial tests of the beam-balanced pumping units equipped with advanced permanent magnet motors and intelligent control stations are presented. It is proved that the use of permanent magnet motors allows to reduce the specific energy consumption for the rise of reservoir fluid, which increases the efficiency of the SRPE.However, the presence of transient processes and generator operating modes of the permanent magnet motors results in the occurrence of significant dynamic loads, which, due to the rigid fixing of the rotor of magnet motor on the reducer shaft, negatively affect the life of the gearbox bearings. It has been shown that the lack of its own bearings in the tested motors causes a high probability

Random spectrum loading of dental implants: An alternative approach to functional performance assessment.

Science.gov (United States)

Shemtov-Yona, K; Rittel, D

2016-09-01

The fatigue performance of dental implants is usually assessed on the basis of cyclic S/N curves. This neither provides information on the anticipated service performance of the implant, nor does it allow for detailed comparisons between implants unless a thorough statistical analysis is performed, of the kind not currently required by certification standards. The notion of endurance limit is deemed to be of limited applicability, given unavoidable stress concentrations and random load excursions, that all characterize dental implants and their service conditions. We propose a completely different approach, based on random spectrum loading, as long used in aeronautical design. The implant is randomly loaded by a sequence of loads encompassing all load levels it would endure during its service life. This approach provides a quantitative and comparable estimate of its performance in terms of lifetime, based on the very fact that the implant will fracture sooner or later, instead of defining a fatigue endurance limit of limited practical application. Five commercial monolithic Ti-6Al-4V implants were tested under cyclic, and another 5 under spectrum loading conditions, at room temperature and dry air. The failure modes and fracture planes were identical for all implants. The approach is discussed, including its potential applications, for systematic, straightforward and reliable comparisons of various implant designs and environments, without the need for cumbersome statistical analyses. It is believed that spectrum loading can be considered for the generation of new standardization procedures and design applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

Community Energy: Analysis of Hydrogen Distributed Energy Systems with Photovoltaics for Load Leveling and Vehicle Refueling

Energy Technology Data Exchange (ETDEWEB)

Steward, D.; Zuboy, J.

2014-10-01

Energy storage could complement PV electricity generation at the community level. Because PV generation is intermittent, strategies must be implemented to integrate it into the electricity system. Hydrogen and fuel cell technologies offer possible PV integration strategies, including the community-level approaches analyzed in this report: (1) using hydrogen production, storage, and reconversion to electricity to level PV generation and grid loads (reconversion scenario); (2) using hydrogen production and storage to capture peak PV generation and refuel hydrogen fuel cell electric vehicles (FCEVs) (hydrogen fueling scenario); and (3) a comparison scenario using a battery system to store electricity for EV nighttime charging (electric charging scenario).

Specification of Energy Assessment Methodologies to Satisfy ISO 50001 Energy Management Standard

Science.gov (United States)

Kanneganti, Harish

Energy management has become more crucial for industrial sector as a way to lower their cost of production and in reducing their carbon footprint. Environmental regulations also force the industrial sector to increase the efficiency of their energy usage. Hence industrial sector started relying on energy management consultancies for improvements in energy efficiency. With the development of ISO 50001 standard, the entire energy management took a new dimension involving top level management and getting their commitment on energy efficiency. One of the key requirements of ISO 50001 is to demonstrate continual improvement in their (industry) energy efficiency. The major aim of this work is to develop an energy assessment methodology and reporting format to tailor the needs of ISO 50001. The developed methodology integrates the energy reduction aspect of an energy assessment with the requirements of sections 4.4.3 (Energy Review) to 4.4.6 (Objectives, Targets and Action Plans) in ISO 50001 and thus helping the facilities in easy implementation of ISO 50001.

A biologically-inspired multi-joint soft exosuit that can reduce the energy cost of loaded walking.

Science.gov (United States)

Panizzolo, Fausto A; Galiana, Ignacio; Asbeck, Alan T; Siviy, Christopher; Schmidt, Kai; Holt, Kenneth G; Walsh, Conor J

2016-05-12

Carrying load alters normal walking, imposes additional stress to the musculoskeletal system, and results in an increase in energy consumption and a consequent earlier onset of fatigue. This phenomenon is largely due to increased work requirements in lower extremity joints, in turn requiring higher muscle activation. The aim of this work was to assess the biomechanical and physiological effects of a multi-joint soft exosuit that applies assistive torques to the biological hip and ankle joints during loaded walking. The exosuit was evaluated under three conditions: powered (EXO_ON), unpowered (EXO_OFF) and unpowered removing the equivalent mass of the device (EXO_OFF_EMR). Seven participants walked on an instrumented split-belt treadmill and carried a load equivalent to 30 % their body mass. We assessed their metabolic cost of walking, kinetics, kinematics, and lower limb muscle activation using a portable gas analysis system, motion capture system, and surface electromyography. Our results showed that the exosuit could deliver controlled forces to a wearer. Net metabolic power in the EXO_ON condition (7.5 ± 0.6 W kg(-1)) was 7.3 ± 5.0 % and 14.2 ± 6.1 % lower than in the EXO_OFF_EMR condition (7.9 ± 0.8 W kg(-1); p = 0.027) and in the EXO_OFF condition (8.5 ± 0.9 W kg(-1); p = 0.005), respectively. The exosuit also reduced the total joint positive biological work (sum of hip, knee and ankle) when comparing the EXO_ON condition (1.06 ± 0.16 J kg(-1)) with respect to the EXO_OFF condition (1.28 ± 0.26 J kg(-1); p = 0.020) and to the EXO_OFF_EMR condition (1.22 ± 0.21 J kg(-1); p = 0.007). The results of the present work demonstrate for the first time that a soft wearable robot can improve walking economy. These findings pave the way for future assistive devices that may enhance or restore gait in other applications.

Basin Testing of Wave Energy Converters in Trondheim: Investigation of Mooring Loads and Implications for Wider Research

Directory of Open Access Journals (Sweden)

Vladimir Krivtsov

2014-04-01

Full Text Available This paper describes the physical model testing of an array of wave energy devices undertaken in the NTNU (Norwegian University of Science and Technology Trondheim basin between 8 and 20 October 2008 funded under the EU Hydralabs III initiative, and provides an analysis of the extreme mooring loads. Tests were completed at 1/20 scale on a single oscillating water column device and on close-packed arrays of three and five devices following calibration of instrumentation and the wave and current test environment. One wave energy converter (WEC was fully instrumented with mooring line load cells, optical motion tracker and accelerometers and tested in regular waves, short- and long-crested irregular waves and current. The wave and current test regimes were measured by six wave probes and a current meter. Arrays of three and five similar WECs, with identical mooring systems, were tested under similar environmental loading with partial monitoring of mooring forces and motions. The majority of loads on the mooring lines appeared to be broadly consistent with both logistic and normal distribution; whilst the right tail appeared to conform to the extreme value distribution. Comparison of the loads at different configurations of WEC arrays suggests that the results are broadly consistent with the hypothesis that the mooring loads should differ. In particular; the results from the tests in short crested seas conditions give an indication that peak loads in a multi WEC array may be considerably higher than in 1-WEC configuration. The test campaign has contributed essential data to the development of Simulink™ and Orcaflex™ models of devices, which include mooring system interactions, and data have also been obtained for inter-tank comparisons, studies of scale effects and validation of mooring system numerical models. It is hoped that this paper will help to draw the attention of a wider scientific community to the dataset freely available from the

Experimental Assessment on the Flexural Bonding Performance of Concrete Beam with GFRP Reinforcing Bar under Repeated Loading

Directory of Open Access Journals (Sweden)

Minkwan Ju

2015-01-01

Full Text Available This study intends to investigate the flexural bond performance of glass fiber-reinforced polymer (GFRP reinforcing bar under repeated loading. The flexural bond tests reinforced with GFRP reinforcing bars were carried out according to the BS EN 12269-1 (2000 specification. The bond test consisted of three loading schemes: static, monotonic, and variable-amplitude loading to simulate ambient loading conditions. The empirical bond length based on the static test was 225 mm, whereas it was 317 mm according to ACI 440 1R-03. Each bond stress on the rib is released and bonding force is enhanced as the bond length is increased. Appropriate level of bond length may be recommended with this energy-based analysis. For the monotonic loading test, the bond strengths at pullout failure after 2,000,000 cycles were 10.4 MPa and 6.5 MPa, respectively: 63–70% of the values from the static loading test. The variable loading test indicated that the linear cumulative damage theory on GFRP bonding may not be appropriate for estimating the fatigue limit when subjected to variable-amplitude loading.

Global Energy Assessment. Toward a Sustainable Future

Energy Technology Data Exchange (ETDEWEB)

Johansson, T B; Nakicenovic, N; Patwardhan, A; Gomez-Echeverri, L [eds.

2012-11-01

The Global Energy Assessment (GEA) brings together over 300 international researchers to provide an independent, scientifically based, integrated and policy-relevant analysis of current and emerging energy issues and options. It has been peer-reviewed anonymously by an additional 200 international experts. The GEA assesses the major global challenges for sustainable development and their linkages to energy; the technologies and resources available for providing energy services; future energy systems that address the major challenges; and the policies and other measures that are needed to realize transformational change toward sustainable energy futures. The GEA goes beyond existing studies on energy issues by presenting a comprehensive and integrated analysis of energy challenges, opportunities and strategies, for developing, industrialized and emerging economies. This volume is an invaluable resource for energy specialists and technologists in all sectors (academia, industry and government) as well as policymakers, development economists and practitioners in international organizations and national governments.

Experimental Assessment on the Hysteretic Behavior of a Full-Scale Traditional Chinese Timber Structure Using a Synchronous Loading Technique

Directory of Open Access Journals (Sweden)

XiWang Shi

2018-01-01

Full Text Available In traditional Chinese timber structures, few tie beams were used between columns, and the column base was placed directly on a stone base. In order to study the hysteretic behavior of such structures, a full-scale model was established. The model size was determined according to the requirements of an eighth grade material system specified in the architectural treatise Ying-zao-fa-shi written during the Song Dynasty. In light of the vertical lift and drop of the test model during horizontal reciprocating motions, the horizontal low-cycle reciprocating loading experiments were conducted using a synchronous loading technique. By analyzing the load-displacement hysteresis curves, envelope curves, deformation capacity, energy dissipation, and change in stiffness under different vertical loads, it is found that the timber frame exhibits obvious signs of self-restoring and favorable plastic deformation capacity. As the horizontal displacement increases, the equivalent viscous damping coefficient generally declines first and then increases. At the same time, the stiffness degrades rapidly first and then decreases slowly. Increasing vertical loading will improve the deformation, energy-dissipation capacity, and stiffness of the timber frame.

Condition Assessment and End-of-Life Prediction System for Electric Machines and Their Loads

Science.gov (United States)

Parlos, Alexander G.; Toliyat, Hamid A.

2005-01-01

An end-of-life prediction system developed for electric machines and their loads could be used in integrated vehicle health monitoring at NASA and in other government agencies. This system will provide on-line, real-time condition assessment and end-of-life prediction of electric machines (e.g., motors, generators) and/or their loads of mechanically coupled machinery (e.g., pumps, fans, compressors, turbines, conveyor belts, magnetic levitation trains, and others). In long-duration space flight, the ability to predict the lifetime of machinery could spell the difference between mission success or failure. Therefore, the system described here may be of inestimable value to the U.S. space program. The system will provide continuous monitoring for on-line condition assessment and end-of-life prediction as opposed to the current off-line diagnoses.

Advances in electric power and energy systems load and price forecasting

CERN Document Server

2017-01-01

A comprehensive review of state-of-the-art approaches to power systems forecasting from the most respected names in the field, internationally. Advances in Electric Power and Energy Systems is the first book devoted exclusively to a subject of increasing urgency to power systems planning and operations. Written for practicing engineers, researchers, and post-grads concerned with power systems planning and forecasting, this book brings together contributions from many of the world’s foremost names in the field who address a range of critical issues, from forecasting power system load to power system pricing to post-storm service restoration times, river flow forecasting, and more. In a time of ever-increasing energy demands, mounting concerns over the environmental impacts of power generation, and the emergence of new, smart-grid technologies, electricity price forecasting has assumed a prominent role within both the academic and industrial ar nas. Short-run forecasting of electricity prices has become nece...

PULPA CUBA MILL ENERGY ASSESSMENT

Directory of Open Access Journals (Sweden)

Juan Pedro Hernández Touset

2015-10-01

Full Text Available An energy study was performed at Pulpa Cuba Paper Mill, located in Sancti Spiritus, where an energy management system was applied according to NC: ISO 50001, in order to assess the energy system by applying energy management systems for energy and water reduction in the paper mill, in which the current steam generation, distribution and consumption system is diagnosed. The proposal of a modified energy scheme with 1 MW Backpressure Steam Turbine Generator and rehabilitation of the original boiler or installing a lower capacity boiler contributes to save financial resources by the concept of water, fuel and electricity. The implementation of four projects will save 3,095,574 CUC / y and an average payback period of about 1 year is expected.

Assessment of wind energy potential in China

Institute of Scientific and Technical Information of China (English)

Zhu Rong; Zhang De; Wang Yuedong; Xing Xuhuang; Li Zechun

2009-01-01

China wind atlas was made by numerical simulation and the wind energy potential in China was calculated. The model system for wind energy resource assessment was set up based on Canadian Wind Energy Simulating Toolkit (WEST) and the simulating method was as follows. First, the weather classes were obtained depend on meteorological data of 30 years. Then, driven by the initial meteorological field produced by each weather class, the meso-scale model ran for the distribution of wind energy resources according each weather class condition one by one. Finally, averaging all the modeling output weighted by the occurrence frequency of each weather class, the annual mean distribution of wind energy resources was worked out. Compared the simulated wind energy potential with other results from several ac-tivities and studies for wind energy resource assessment, it is found that the simulated wind energy potential in mainland of China is 3 times that from the second and the third investigations for wind energy resources by CMA, and is similar to the wind energy potential obtained by NREL in Solar and Wind Energy Resource Assessment (SWERA) project. The simulated offshore wind energy potential of China seems smaller than the true value. According to the simulated results of CMA and considering lots of limited factors to wind energy development, the final conclusion can be obtained that the wind energy availability in China is 700～1 200 GW, in which 600～1 000 GW is in mainland and 100～200 GW is on offshore, and wind power will become the important part of energy composition in future.

Comparative Assessment of Energy Supply Options

International Nuclear Information System (INIS)

Rogner, H.-H.; Vladu, I. F.

2000-01-01

The complexity facing today's energy planners and decision-makers, particularly in electricity sector, has increased. They must take into account many elements in selecting technologies and strategies that will impact near term energy development and applications in their countries. While costs remain a key factor, tradeoffs between the demands of environmental protection and economic development will have to be made. This fact, together with the needs of many countries to define their energy and electricity programmes in a sustainable manner, has resulted in a growing interest in the application of improved data, tools and techniques for comparative assessment of different electricity generation options, particularly from an environmental and human health viewpoint. Although global emissions of greenhouse gases and other pollutants, e.g. SO 2 , NO x and particulate, must be reduced, the reality today is that these emissions are increasing and are expected to continue increasing. In examining the air pollutants, as well as water effluents and solid waste generated by electricity production, it is necessary to assess the full energy chain from fuel extraction to waste disposal, including the production of construction and auxiliary materials. The paper describes this concept and illustrates its implementation for assessing and comparing electricity generation costs, emissions, wastes and other environmental burdens from different energy sources. (author)

The Methodology for Integral Assessment of the Impact of Renewable Energy on the Environment under Non-Stationary Economy

OpenAIRE

Petrakov Iaroslav V.; Hnedina Kateryna V.

2017-01-01

The need to reduce anthropogenic load, eliminate threats to environmental safety and provide ecologically oriented development are one of the main global challenges of our time. At the same time, the replacement of traditional energy sources with alternatives ones requires a quantitative assessment of direct and indirect environmental impacts. The article analyzes the dynamics and structure of pollution in Ukraine in terms of its sources and forms as well as their impact on the carbon product...

Adaptive algorithm for predicting increases in central loads of electrical energy systems

Energy Technology Data Exchange (ETDEWEB)

Arbachyauskene, N A; Pushinaytis, K V

1982-01-01

An adaptive algorithm for predicting increases in central loads of the electrical energy system is suggested for the task of evaluating the condition. The algorithm is based on the Kalman filter. In order to calculate the coefficient of intensification, the a priori assigned noise characteristics with low accuracy are used only in the beginning of the calculation. Further, the coefficient of intensification is calculated from the innovation sequence. This approach makes it possible to correct errors in the assignment of the statistical noise characteristics and to follow their changes. The algorithm is experimentally verified.

Environmental assessment of energy production from waste and biomass

DEFF Research Database (Denmark)

Tonini, Davide

. To evaluate the environmental and energy performance of bioenergy and wasteto-energy systems life cycle assessment was used in this thesis. This was supported by other tools such as material, substance, energy flow analysis and energy system analysis. The primary objective of this research was to provide...... a consistent framework for the environmental assessment of innovative bioenergy and waste-to-energy systems including the integration of LCA with other tools (mentioned earlier). The focus was on the following aspects: - Evaluation of potential future energy scenarios for Denmark. This was doneby integrating...... assessing the environmental performance of the waste refinery, a detailed knowledge of the waste composition is recommendable as this determines the energy outputs and thereby the assessment results. The benefits offered by the waste refinery compared with incinerators and MBT plants are primarily related...

Research, Development and Demonstration of Peak Load Reduction on Distribution Feeders Using Distributed Energy Resources for the City of Fort Collins

Energy Technology Data Exchange (ETDEWEB)

Sumner, Dennis [City of Fort Collins Utilities, CO (United States); Vosburg, Tom [City of Fort Collins Utilities, CO (United States); Brunner, Steve [Brendle Group, Fort Collins, CO (United States); Gates, Judy [Woodward, Inc., Fort Collins, CO (United States); Howard, Nathan [Spirae, Inc., Fort Collins, CO (United States); Merton, Andrew [Spirae, Inc., Fort Collins, CO (United States); Wright, Don [Spirae, Inc., Fort Collins, CO (United States); Birlingmair, Doug [Spirae, Inc., Fort Collins, CO (United States)

2015-10-01

This project titled “Research, Development and Demonstration of Peak Load Reduction on Distribution Feeders Using Distributed Energy Resources for the City of Fort Collins” evolved in response to the Department of Energy’s (DOE) Funding Opportunity Announcement (FOA) Number DE-PS26-07NT43119. Also referred to as the Fort Collins Renewable and Distributed System Integration (RDSI) Project, the effort was undertaken by a diverse group of local government, higher education and business organizations; and was driven by three overarching goals: I. Fulfill the requirements of the DOE FOA’s Area of Interest 2: Renewable and Distributed System Integration; most notably, to demonstrate the ability to reduce electric system distribution feeder peak load by 15% or more through the coordinated use of Distributed Energy Resources (DER). II. Advance the expertise, technologies and infrastructure necessary to support the long term vision of the Fort Collins Zero Energy District (FortZED) and move towards creating a zero energy district in the Fort Collins “Old Town” area. III. Further the goals of the City of Fort Collins Energy Policy, including the development of a Smart Grid-enabled distribution system in Fort Collins, expanded use of renewable energy, increased energy conservation, and peak load reduction. Through the collaborative efforts of the partner organizations, the Fort Collins RDSI project was successful in achieving all three of these goals. This report is organized into two distinct sections corresponding to the two phases of the project: • Part 1: Feeder Peak Load Reduction and the FortZED Initiative. • Part 2: Forming and Operating Utility Microgrids and Managing Load and Production Variability The original project scope addressed the Part 1 feeder peak load reduction. That work took place from 2009 through 2011 and was largely complete when the project scope was amended to include a demonstration of microgrid operations. While leveraging the

Hydrogen energy assessment

Energy Technology Data Exchange (ETDEWEB)

Salzano, F J; Braun, C [eds.

1977-09-01

The purpose of this assessment is to define the near term and long term prospects for the use of hydrogen as an energy delivery medium. Possible applications of hydrogen are defined along with the associated technologies required for implementation. A major focus in the near term is on industrial uses of hydrogen for special applications. The major source of hydrogen in the near term is expected to be from coal, with hydrogen from electric sources supplying a smaller fraction. A number of potential applications for hydrogen in the long term are identified and the level of demand estimated. The results of a cost benefit study for R and D work on coal gasification to hydrogen and electrolytic production of hydrogen are presented in order to aid in defining approximate levels of R and D funding. A considerable amount of data is presented on the cost of producing hydrogen from various energy resources. A key conclusion of the study is that in time hydrogen is likely to play a role in the energy system; however, hydrogen is not yet competitive for most applications when compared to the cost of energy from petroleum and natural gas.

Energy Efficiency, Water Efficiency, and Renewable Energy Site Assessment: Mendenhall Glacier Visitor Center, Juneau, Alaska

Energy Technology Data Exchange (ETDEWEB)

Salasovich, James [National Renewable Energy Lab. (NREL), Golden, CO (United States); LoVullo, David [National Renewable Energy Lab. (NREL), Golden, CO (United States); Kandt, Alicen [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2016-01-21

This report summarizes results from the energy efficiency, water efficiency, and renewable energy site assessment of the Mendenhall Glacier Visitor Center and site in Juneau, Alaska. The assessment is an American Society of Heating, Refrigerating, and Air-Conditioning Engineers Level 2 audit and meets Energy Independence and Security Act requirements. A team led by the U.S. Department of Energy's National Renewable Energy Laboratory conducted the assessment with U.S. Forest Service personnel August 19-20, 2015, as part of ongoing efforts by USFS to reduce energy and water use.

Preliminary Load Estimations for DEXA Wave Energy Device - Hanstholm, Denmark

DEFF Research Database (Denmark)

Kofoed, Jens Peter

by DEXA Wave Energy ApS, in regular and irregular wave states, as described in Assessment of Wave Energy Devices. Best Practice as used in Denmark (Frigaard et al., 2008). The length scale of the model was 1:20 compared to a full scale device suitable fro the Danish part of the North Sea, according...... to DEXA Wave Energy ApS. The tests were carried out at Dept. of Civil Engineering, Aalborg University (AAU) in the 3D deep water wave tank. The displacement and force applied to a power take off system, provided by DEXA Wave Energy ApS, were measured and used for calculation of power available...... to the power take-off....

Lessons Learned from Net Zero Energy Assessments and Renewable Energy Projects at Military Installations

Energy Technology Data Exchange (ETDEWEB)

Callahan, M.; Anderson, K.; Booth, S.; Katz, J.; Tetreault, T.

2011-09-01

Report highlights the increase in resources, project speed, and scale that is required to achieve the U.S. Department of Defense (DoD) energy efficiency and renewable energy goals and summarizes the net zero energy installation assessment (NZEI) process and the lessons learned from NZEI assessments and large-scale renewable energy projects implementations at DoD installations.

Assessment on health and energy sources

International Nuclear Information System (INIS)

Acket, C.; Yvon, M.

2013-01-01

After having recalled some issues related to the prevention of environmental health risks and mentioned in the preparation of the debate on energy transition in France, this document gathers actual objective elements for an assessment of health impact of the different energy sources. It discusses the impacts on health (mortality, sicknesses and diseases) of fossil fuels (coal and its wastes, gas), of renewable energies, of nuclear energy. For this last one, the document outlines the lack of documentation for various topics, discusses some results published on the dose impact of nuclear operation, and comment the issue of waste storage. It also recalls the main accidents (Three Mile Island, Chernobyl, and Fukushima) and some of the known and assessed impacts. The third part proposes comparisons between the different energy sources in terms of deadly accidents, of pollution and greenhouse effect (current and late mortality), of released radioactivity (release sources and collective dose). In conclusion, the authors outline that the impact on health of environmental risks must be one of the essential issues for the definition of energy policy, and discuss the resulting implications. Various data are provided in appendix: energy in France and in the world, origins of radioactivity

Assessment of Calculation Procedures for Piles in Clay Based on Static Loading Tests

DEFF Research Database (Denmark)

Augustesen, Anders; Andersen, Lars

2008-01-01

College in London. The calculation procedures are assessed based on an established database of static loading tests. To make a consistent evaluation of the design methods, corrections related to undrained shear strength and time between pile driving and testing have been employed. The study indicates...... that the interpretation of the field tests is of paramount importance, both with regard to the soil profile and the loading conditions. Based on analyses of 253 static pile loading tests distributed on 111 sites, API-RP2A provides the better description of the data. However, it should be emphasised that some input......Numerous methods are available for the prediction of the axial capacity of piles in clay. In this paper, two well-known models are considered, namely the current API-RP2A (1987 to present) and the recently developed ICP method. The latter is developed by Jardine and his co-workers at Imperial...

Indicative energy technology assessment of advanced rechargeable batteries

International Nuclear Information System (INIS)

Hammond, Geoffrey P.; Hazeldine, Tom

2015-01-01

Highlights: • Several ‘Advanced Rechargeable Battery Technologies’ (ARBT) have been evaluated. • Energy, environmental, economic, and technical appraisal techniques were employed. • Li-Ion Polymer (LIP) batteries exhibited the most attractive energy and power metrics. • Lithium-Ion batteries (LIB) and LIP batteries displayed the lowest CO 2 and SO 2 emissions per kW h. • Comparative costs for LIB, LIP and ZEBRA batteries were estimated against Nickel–Cadmium cells. - Abstract: Several ‘Advanced Rechargeable Battery Technologies’ (ARBT) have been evaluated in terms of various energy, environmental, economic, and technical criteria. Their suitability for different applications, such as electric vehicles (EV), consumer electronics, load levelling, and stationary power storage, have also been examined. In order to gain a sense of perspective regarding the performance of the ARBT [including Lithium-Ion batteries (LIB), Li-Ion Polymer (LIP) and Sodium Nickel Chloride (NaNiCl) {or ‘ZEBRA’} batteries] they are compared to more mature Nickel–Cadmium (Ni–Cd) batteries. LIBs currently dominate the rechargeable battery market, and are likely to continue to do so in the short term in view of their excellent all-round performance and firm grip on the consumer electronics market. However, in view of the competition from Li-Ion Polymer their long-term future is uncertain. The high charge/discharge cycle life of Li-Ion batteries means that their use may grow in the electric vehicle (EV) sector, and to a lesser extent in load levelling, if safety concerns are overcome and costs fall significantly. LIP batteries exhibited attractive values of gravimetric energy density, volumetric energy density, and power density. Consequently, they are likely to dominate the consumer electronics market in the long-term, once mass production has become established, but may struggle to break into other sectors unless their charge/discharge cycle life and cost are improved

Urban energy conversion and its effects

International Nuclear Information System (INIS)

Geiger, B.

1981-01-01

The extent to which the building up and energy conversion affect the quality and energy economy of living space is shown by the example of Munich. The comparison of the energy economy of various ecological systems give qualified information for assessing the thermal loading in densely inhabited areas and show the basic differences between built-up and country areas. (DG) [de

Subharmonic beam-loading in electron linear accelerators

International Nuclear Information System (INIS)

Gallagher, W.J.

1983-01-01

The intention of operating an electron linear accelerator subharmonically beam loaded for free electron laser application requires justification of the beam-loaded energy gain equation. The mode of operation typically planned is 5 to 10 nanocoulombs single RF cycle pulses at 25 to 50 nanosecond intervals. This inquiry investigates the details of this sort of beam loading and discusses the performance achievable. Several other investigations of single bunch beam loading have been undertaken, notably at SLAC, where it has been found experimentally that the beam-loading varies directly as the bunch charge and independently of its energy; that investigation also included radiation effects of the wake field and losses owing to parasitic effects of higher order modes. In the case of beam loading where there are multiple pulses transiting at the same time, and spaced far enough apart that significant RF power is introduced between pulses, the energy gain may be calculated by dividing the waveguide into a number of segments, each equal in length to the integral of the interpulse time and the local group velocity. Equations which reveal that the net energy gain in the steady state is the sum of the energy gains in these segments, which compute the initial field intensity, and which calculate the energy gain in the subharmonic case on the basis of the equivalent beam current are presented

A method for rapid vulnerability assessment of structures loaded by outside blasts

International Nuclear Information System (INIS)

Cizelj, Leon; Leskovar, Matjaz; Cepin, Marko; Mavko, Borut

2007-01-01

The blast have in most cases not been assumed as design basis loads of nuclear power plant buildings and structures. Recent developments however stimulated a number of analyses quantifying the potential effect of such loads. An effort was therefore made by the authors to revisit simple and robust structural analysis methods and to propose their use in the vulnerability assessment of blast-loaded structures. The leading idea is to break the structure into a set of typical structural elements, for which the response is estimated by the use of slightly modified handbook formulas. The proposed method includes provisions to predict the inelastic response and failure. Simplicity and versatility of the method facilitate its use in structural reliability calculations. The most important aspects of the proposed method are presented along with illustrative sample applications demonstrating: - results comparable to full scale dynamic simulations using explicit finite element codes and - the performance of the method in screening the existing structures and providing the structural reliability information for the vulnerability analysis. (author)

Energy performance assessment methodology

Energy Technology Data Exchange (ETDEWEB)

Platzer, W.J. [Fraunhofer Inst. for Solar Energy Systems, Freiburg (Germany)

2006-01-15

The energy performance of buildings are intimately connected to the energy performance of building envelopes. The better we understand the relation between the quality of the envelope and the energy consumption of the building, the better we can improve both. We have to consider not only heating but all service energies related to the human comfort in the building, such as cooling, ventilation, lighting as well. The complexity coming from this embracing approach is not to be underestimated. It is less and less possible to realted simple characteristic performance indicators of building envelopes (such as the U-value) to the overall energy performance. On the one hand much more paramters (e.g. light transmittance) come into the picture we have to assess the product quality in a multidimensional world. Secondly buildings more and more have to work on a narrow optimum: For an old, badly insulated building all solar gains are useful for a high-performance building with very good insulation and heat recovery systems in the ventilation overheating becomes more likely. Thus we have to control the solar gains, and sometimes we need high gains, sometimes low ones. And thirdly we see that the technology within the building and the user patterns and interactions as well influence the performance of a building envelope. The aim of this project within IEA Task27 was to improve our knowledge on the complex situation and also to give a principal approach how to assess the performance of the building envelope. The participants have contributed to this aim not pretending that we have reached the end. (au)

Assessing the future of energy

International Nuclear Information System (INIS)

Moncomble, J.E.

2015-01-01

The World Energy Council has designed 2 tools named Jazz and Symphonie that allow the assessment of the potential impacts of energy choices on the future in terms of climate warming, investments, energy mix,... The Jazz roadmap aims at energy equity which means individual access to energy at a reasonable cost while the Symphonie roadmap focuses on environmental issues through appropriate practice and coordinated international policies. Both tools are integrated it means that they describe a whole world by most of its aspects: population, GDP per capita, number of cars by inhabitant, economic growth... A basic application of both tools shows that in 2050 the nuclear power will have increased (compared to today's level) but the share of nuclear power in the energy mix will have decreased for Jazz and increased for Symphonie. (A.C.)

Reducing Plug and Process Loads for a Large Scale, Low Energy Office Building: NREL's Research Support Facility; Preprint

Energy Technology Data Exchange (ETDEWEB)

Lobato, C.; Pless, S.; Sheppy, M.; Torcellini, P.

2011-02-01

This paper documents the design and operational plug and process load energy efficiency measures needed to allow a large scale office building to reach ultra high efficiency building goals. The appendices of this document contain a wealth of documentation pertaining to plug and process load design in the RSF, including a list of equipment was selected for use.

A coupled nuclear reactor thermal energy storage system for enhanced load following operation

International Nuclear Information System (INIS)

Alameri, Saeed A.; King, Jeffrey C.

2013-01-01

Nuclear power plants operate most economically at a constant power level, providing base load electric power. In an energy grid containing a high fraction of renewable power sources, nuclear reactors may be subject to significantly variable power demands. These variable power demands can negatively impact the effective capacity factor of the reactor and result in severe economic penalties. Coupling a nuclear reactor to a large thermal energy storage block will allow the reactor to better respond to variable power demands. In the system described in this paper, a Prismatic core Advanced High Temperature Reactor supplies constant power to a lithium chloride molten salt thermal energy storage block that provides thermal power as needed to a closed Brayton cycle energy conversion system. During normal operation, the thermal energy storage block stores thermal energy during the night for use in the times of peak demand during the day. In this case, the nuclear reactor stays at a constant thermal power level. After a loss of forced circulation, the reactor reaches a shut down state in less than half an hour and the average fuel, graphite and coolant temperatures remain well within the design limits over the duration of the transient, demonstrating the inherent safety of the coupled system. (author)

Uncertainty of Energy Consumption Assessment of Domestic Buildings

DEFF Research Database (Denmark)

Brohus, Henrik; Heiselberg, Per; Simonsen, A.

2009-01-01

In order to assess the influence of energy reduction initiatives, to determine the expected annual cost, to calculate life cycle cost, emission impact, etc. it is crucial to be able to assess the energy consumption reasonably accurate. The present work undertakes a theoretical and empirical study...... of the uncertainty of energy consumption assessment of domestic buildings. The calculated energy consumption of a number of almost identical domestic buildings in Denmark is compared with the measured energy consumption. Furthermore, the uncertainty is determined by means of stochastic modelling based on input...... to correspond reasonably well; however, it is also found that significant differences may occur between calculated and measured energy consumption due to the spread and due to the fact that the result can only be determined with a certain probability. It is found that occupants' behaviour is the major...

Some Environmental and Economic Aspects of Energy Saving Measures in Houses. An estimation model for total energy consumption and emissions to air from the Norwegian dwelling stock, and a life cycle assessment method for energy saving measures in houses

Energy Technology Data Exchange (ETDEWEB)

Myhre, L

1995-12-01

Motivated by the need to reduce the total energy consumption and the environmental load from society, this doctoral thesis discusses energy conservation measures on existing houses. Alternative additional thermal insulation measures are assessed using an interdisciplinary life cycle approach. The first task is to develop an interdisciplinary assessment method for building improvement measures, taking account of energy consumption, resource consumption, emissions to air of environmentally harmful gases, and economic costs during the entire life cycle of the building. The second task is to develop an estimation model for the total energy consumption and emissions to air of environmentally harmful gases from the dwelling stock of Norway. Finally, the third task is to assess the total energy saving potential and the total environmental benefits of energy saving measures in houses on a national level, including only life cycle analyses of additional thermal insulation measures on single houses. Chap 2 describes the dwelling stock in Norway. Chaps 3 and 4 present an estimation model for total energy consumption and emissions to air from the dwelling stock, and calculations using the model. Chaps 5 and 6 propose and use a calculation method for the assessment of additional thermal insulation measures, using a ``cradle-to-grave`` approach. Since hydroelectric power is the main energy source in this sector in Norway, estimated payback periods for emissions to air are long. But hydroelectric power saved in this sector may be used to obtain reduction in fossil fuel use in other sectors as discussed in Chap 7. Some of the topics discussed are further elaborated on in appendices. 107 refs., 39 figs, 88 tabs.

Patrick Air Force Base integrated resource assessment. Volume 2, Baseline detail

Energy Technology Data Exchange (ETDEWEB)

Wahlstrom, R.R.; King, D.A.; Parker, S.A.; Sandusky, W.F.

1993-08-01

The US Air Force has tasked the Pacific Northwest Laboratory (PNL), in support of the US Department of Energy (DOE) Federal Energy Management Program (FEMP), to assess energy use at Patrick Air Force Base (AFB). The information obtained from this assessment will be used in identifying energy resource opportunities to reduce overall energy consumption on the base. The primary focus of this report is to assess the current baseline energy consumption at Patrick AFB. It is a comparison report to Volume 1, the Executive Summary, and Volume 3, the Resource Assessment. This assessment requires that information be obtained and characterized for buildings, utilities, energy sources, energy uses, and load profile information to be used to improve the characterization of energy use on the base. The characteristics of electricity, natural gas, and No. 2 fuel oil are analyzed for on-base facilities and housing. The assessment examines basic regional information used to determine energy-use intensity (EUI) values for Patrick AFB facilities by building, fuel type, and energy end use. It also provides a summary of electricity consumption from Florida Power and Light Company (FPL) metered data for 1985-1991. Load profile information obtained from FPL data is presented for the north and south substations for the four seasons of the year, including weekdays and weekends.

Assessment of CO2 free energy options

International Nuclear Information System (INIS)

Cavlina, N.; Raseta, D.; Matutinovic, I.

2014-01-01

One of the European Union climate and energy targets is to significantly reduce CO 2 emissions, at least 20% by 2020, compared to 1990. In the power industry, most popular solution is use of solar and wind power. Since their production varies significantly during the day, for the purpose of base-load production they can be paired with gas-fired power plant. Other possible CO 2 -free solution is nuclear power plant. This article compared predicted cost of energy production for newly built nuclear power plant and newly built combination of wind or solar and gas-fired power plant. Comparison was done using Levelized Unit of Energy Cost (LUEC). Calculations were performed using the Monte Carlo method. For input parameters that have biggest uncertainty (gas cost, CO 2 emission fee) those uncertainties were addressed not only through probability distribution around predicted value, but also through different scenarios. Power plants were compared based on their economic lifetime. (authors)

Optimized Loading for Particle-in-cell Gyrokinetic Simulations

International Nuclear Information System (INIS)

Lewandowski, J.L.V.

2004-01-01

The problem of particle loading in particle-in-cell gyrokinetic simulations is addressed using a quadratic optimization algorithm. Optimized loading in configuration space dramatically reduces the short wavelength modes in the electrostatic potential that are partly responsible for the non-conservation of total energy; further, the long wavelength modes are resolved with good accuracy. As a result, the conservation of energy for the optimized loading is much better that the conservation of energy for the random loading. The method is valid for any geometry and can be coupled to optimization algorithms in velocity space

Assessing the quality of energy supplied by small renewable energy systems; Avaliacao da qualidade da energia fornecida por sistemas renovaveis isolados de pequeno porte

Energy Technology Data Exchange (ETDEWEB)

Galhardo, Marcos Andre Barros; Pinho, Joao Tavares [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Grupo de Estudos e Desenvolvimento de Alternativas Energeticas], e-mail: galhardo@ufpa.br, E-mail: jtpinho@ufpa.br

2004-07-01

This paper makes an analysis of the power quality supplied by small renewable energy systems with energy storage in a battery bank and its DC/AC conversion by an inverter. It is shown that the power quality supplied by stand-alone renewable systems depends on the used inverter, specially of its voltage waveform, the load supplied and the voltage level in the battery bank, which has a direct influence on the value of the rms output voltage of the inverter. For these analysis, measurements are presented for typical loads used in these systems as illumination, TV, refrigerator, etc., and combinations of these loads, supplied by different waveforms. (author)

Can storage reduce electricity consumption? A general equation for the grid-wide efficiency impact of using cooling thermal energy storage for load shifting

Science.gov (United States)

Deetjen, Thomas A.; Reimers, Andrew S.; Webber, Michael E.

2018-02-01

This study estimates changes in grid-wide, energy consumption caused by load shifting via cooling thermal energy storage (CTES) in the building sector. It develops a general equation for relating generator fleet fuel consumption to building cooling demand as a function of ambient temperature, relative humidity, transmission and distribution current, and baseline power plant efficiency. The results present a graphical sensitivity analysis that can be used to estimate how shifting load from cooling demand to cooling storage could affect overall, grid-wide, energy consumption. In particular, because power plants, air conditioners and transmission systems all have higher efficiencies at cooler ambient temperatures, it is possible to identify operating conditions such that CTES increases system efficiency rather than decreasing it as is typical for conventional storage approaches. A case study of the Dallas-Fort Worth metro area in Texas, USA shows that using CTES to shift daytime cooling load to nighttime cooling storage can reduce annual, system-wide, primary fuel consumption by 17.6 MWh for each MWh of installed CTES capacity. The study concludes that, under the right circumstances, cooling thermal energy storage can reduce grid-wide energy consumption, challenging the perception of energy storage as a net energy consumer.

Matching of renewable source of energy generation graphs and electrical load in local energy system

Science.gov (United States)

Lezhniuk, Petro; Komar, Vyacheslav; Sobchuk, Dmytro; Kravchuk, Sergiy; Kacejko, Piotr; Zavidsky, Vladislav

2017-08-01

The paper contains the method of matching generation graph of photovoltaic electric stations and consumers. Characteristic feature of this method is the application of morphometric analysis for assessment of non-uniformity of the integrated graph of energy supply, optimal coefficients of current distribution, that enables by mean of refining the powers, transferring in accordance with the graph , to provide the decrease of electric energy losses in the grid and transport task, as the optimization tool.

Life cycle assessment of renewable energy sources

CERN Document Server

Singh, Anoop; Olsen, Stig Irving

2013-01-01

Governments are setting challenging targets to increase the production of energy and transport fuel from sustainable sources. The emphasis is increasingly on renewable sources including wind, solar, geothermal, biomass based biofuel, photovoltaics or energy recovery from waste. What are the environmental consequences of adopting these other sources? How do these various sources compare to each other? Life Cycle Assessment of Renewable Energy Sources tries to answer these questions based on the universally adopted method of Life Cycle Assessment (LCA). This book introduces the concept and impor

A simplified equivalent circuit model for simulation of Pb-acid batteries at load for energy storage application

Energy Technology Data Exchange (ETDEWEB)

Zhu, Wenhua H.; Zhu Ying [Center for Microfibrous Materials, Department of Chemical Engineering, 212 Ross Hall, Auburn University, AL 36849-5127 (United States); Tatarchuk, Bruce J., E-mail: brucet@eng.auburn.edu [Center for Microfibrous Materials, Department of Chemical Engineering, 212 Ross Hall, Auburn University, AL 36849-5127 (United States)

2011-08-15

Highlights: {yields} Pb-acid battery is reexamined in electrode structure and capacitance enhancement. {yields} Pb-acid batteries were tested through the electrochemical impedance at loads. {yields} Electrode behaviors are evaluated by simulation using an equivalent circuit model. {yields} A defective and a failed Pb-acid battery was used in non-destructive analysis. {yields} Potential applications are for power reserve and sustainable electricity storage. - Abstract: Three main types of battery chemistries in consideration for vehicle applications are Pb-acid, nickel-metal hydride, and lithium-ion batteries. Lead-acid batteries are widely used in traditional automotive applications for many years. Higher voltage, high-rate discharge capability, good specific energy, lower temperature performance, lower thermal management requirement, and low-cost in both manufacturing and recycling are the advantages of the rechargeable battery. Disadvantages of the lead-acid battery are: weight concerns of lead metal (lower energy density and lower power density) and limited cycle-life (especially in deep-cycle duties). If two major disadvantages have been significantly changed to a proper state to compete with other battery chemistries, the Pb-acid battery is still a good candidate in considering of cost/performance ratio. The lead-acid battery is always a good power source for fast starting of cold vehicles, for recharging from either a stop-start braking system, or for a charge from the engine itself, which consumes battery energy or stores electricity back into chemical energy. The main reasons for reexamining this battery chemistry are cost-savings and life-cycling considerations upon advances in electrode structure design and enhancement of capacitance behavior inside the battery pack. Several Pb-acid batteries were evaluated and tested through a unique method, i.e., the electrochemical impedance method at different loads, in order to characterize and further understand the

A simplified equivalent circuit model for simulation of Pb-acid batteries at load for energy storage application

International Nuclear Information System (INIS)

Zhu, Wenhua H.; Zhu Ying; Tatarchuk, Bruce J.

2011-01-01

Highlights: → Pb-acid battery is reexamined in electrode structure and capacitance enhancement. → Pb-acid batteries were tested through the electrochemical impedance at loads. → Electrode behaviors are evaluated by simulation using an equivalent circuit model. → A defective and a failed Pb-acid battery was used in non-destructive analysis. → Potential applications are for power reserve and sustainable electricity storage. - Abstract: Three main types of battery chemistries in consideration for vehicle applications are Pb-acid, nickel-metal hydride, and lithium-ion batteries. Lead-acid batteries are widely used in traditional automotive applications for many years. Higher voltage, high-rate discharge capability, good specific energy, lower temperature performance, lower thermal management requirement, and low-cost in both manufacturing and recycling are the advantages of the rechargeable battery. Disadvantages of the lead-acid battery are: weight concerns of lead metal (lower energy density and lower power density) and limited cycle-life (especially in deep-cycle duties). If two major disadvantages have been significantly changed to a proper state to compete with other battery chemistries, the Pb-acid battery is still a good candidate in considering of cost/performance ratio. The lead-acid battery is always a good power source for fast starting of cold vehicles, for recharging from either a stop-start braking system, or for a charge from the engine itself, which consumes battery energy or stores electricity back into chemical energy. The main reasons for reexamining this battery chemistry are cost-savings and life-cycling considerations upon advances in electrode structure design and enhancement of capacitance behavior inside the battery pack. Several Pb-acid batteries were evaluated and tested through a unique method, i.e., the electrochemical impedance method at different loads, in order to characterize and further understand the improved electrode

Experimental Results of a DC Bus Voltage Level Control for a Load-Controlled Marine Current Energy Converter

Directory of Open Access Journals (Sweden)

Johan Forslund

2015-05-01

Full Text Available This paper investigates three load control methods for a  marine current energy converter using a vertical axis current  turbine (VACT mounted on a permanent magnet synchronous generator  (PMSG. The three cases are; a fixed AC load, a fixed pulse width  modulated (PWM DC load and DC bus voltage control of a DC  load. Experimental results show that the DC bus voltage control  reduces the variations of rotational speed by a factor of 3.5 at the cost  of slightly increased losses in the generator and transmission lines.  For all three cases, the tip speed ratio \\(\\lambda\\ can be kept close to  the expected \\(\\lambda_{opt}\\. The power coefficient is estimated to be  0.36 at \\(\\lambda_{opt}\\; however, for all three cases, the average  extracted power was about \\(\\sim 19\\\\%. A maximum power point  tracking (MPPT system, with or without water velocity measurement,  could increase the average extracted power.

Assessment of rural energy resources

International Nuclear Information System (INIS)

Rijal, K.; Bansal, N.K.; Grover, P.D.

1990-01-01

This article presents the methodological guidelines used to assess rural energy resources with an example of its application in three villages each from different physiographic zones of Nepal. Existing energy demand patterns of villages are compared with estimated resource availability, and rural energy planning issues are discussed. Economics and financial supply price of primary energy resources are compared, which provides insight into defective energy planning and policy formulation and implication in the context of rural areas of Nepal. Though aware of the formidable consequences, the rural populace continues to exhaust the forest as they are unable to find financially cheaper alternatives. Appropriate policy measures need to be devised by the government to promote the use of economically cost-effective renewable energy resources so as to change the present energy usage pattern to diminish the environmental impact caused by over exploitation of forest resources beyond their regenerative capacity

Wind effects on long-span bridges: Probabilistic wind data format for buffeting and VIV load assessments

Science.gov (United States)

Hoffmann, K.; Srouji, R. G.; Hansen, S. O.

2017-12-01

The technology development within the structural design of long-span bridges in Norwegian fjords has created a need for reformulating the calculation format and the physical quantities used to describe the properties of wind and the associated wind-induced effects on bridge decks. Parts of a new probabilistic format describing the incoming, undisturbed wind is presented. It is expected that a fixed probabilistic format will facilitate a more physically consistent and precise description of the wind conditions, which in turn increase the accuracy and considerably reduce uncertainties in wind load assessments. Because the format is probabilistic, a quantification of the level of safety and uncertainty in predicted wind loads is readily accessible. A simple buffeting response calculation demonstrates the use of probabilistic wind data in the assessment of wind loads and responses. Furthermore, vortex-induced fatigue damage is discussed in relation to probabilistic wind turbulence data and response measurements from wind tunnel tests.

Real-Time Vehicle Energy Management System Based on Optimized Distribution of Electrical Load Power

Directory of Open Access Journals (Sweden)

Yuefei Wang

2016-10-01

Full Text Available As a result of severe environmental pressure and stringent government regulations, refined energy management for vehicles has become inevitable. To improve vehicle fuel economy, this paper presents a bus-based energy management system for the electrical system of internal combustion engine vehicles. Both the model of an intelligent alternator and the model of a lead-acid battery are discussed. According to these models, the energy management for a vehicular electrical system is formulated as a global optimal control problem which aims to minimize fuel consumption. Pontryagin’s minimum principle is applied to solve the optimal control problem to realize a real-time control strategy for electrical energy management in vehicles. The control strategy can change the output of the intelligent alternator and the battery with the changes of electrical load and driving conditions in real-time. Experimental results demonstrate that, compared to the traditional open-loop control strategy, the proposed control strategy for vehicle energy management can effectively reduce fuel consumption and the fuel consumption per 100 km is decreased by approximately 1.7%.

An energy impact assessment of indoor air quality acceptance for air-conditioned offices

International Nuclear Information System (INIS)

Wong, L.T.; Mui, K.W.; Shi, K.L.; Hui, P.S.

2008-01-01

Treatment of fresh air in ventilation systems for the air-conditioning consumes a considerable amount of energy and affects the indoor air quality (IAQ). The ventilation demand is primarily related to the occupant load. In this study, the ventilation demands due to occupant load variations and occupant acceptability were examined against certain IAQ objectives using the mass balance of carbon dioxide (CO 2 ) concentrations in an air-conditioned office. In particular, this study proposed a ventilation model for the consideration of the occupant load variations and occupant acceptability based on the regional survey of typical offices (422 samples) in Hong Kong. The model was applied to evaluate the relative energy performance of different IAQ objectives in ventilation systems for typical office buildings in Hong Kong. The results showed that the energy consumption of a ventilation system would be correlated with the occupant load and acceptability in the air-conditioned office. Indicative CO 2 levels of 800 ppmv, 1000 ppmv and 1200 ppmv corresponding to 83%, 97% and 99.7% survey samples were shown, corresponding to the thermal energy consumptions of 1500 MJ m -2 yr -1 , 960 MJ m -2 yr -1 and 670 MJ m -2 yr -1 , respectively. In regards to the monetary issue, an annual value of HK$ 762 million per year in electrical consumption could be saved in all office buildings in Hong Kong when the indoor target CO 2 concentration is increased from 1000 ppmv to 1200 ppmv. To achieve an excellent IAQ following the existing design standard, i.e. to decrease the CO 2 level from 1000 ppmv to 800 ppmv, 56% additional energy would be consumed, corresponding to an annual value of HK$ 1,419 million, even though the occupant acceptability is only improved from 81% to 86%. The development of the models in this study would be useful for the energy performance evaluation of ventilation systems in air-conditioned offices

The barriers to energy efficiency in China: Assessing household electricity savings and consumer behavior in Liaoning Province

International Nuclear Information System (INIS)

Feng Dianshu; Sovacool, Benjamin K.; Khuong Minh Vu

2010-01-01

This article investigates the barriers to energy efficiency at the residential sector within one province in China and explores patterns of household electricity consumption. The article presents the results of a survey questionnaire distributed to more than 600 households in Liaoning Province, field research at various Liaoning government agencies, and research interviews of Liaoning government officials to determine the efficacy of their energy efficiency efforts in China. It then investigates the extent that electricity consumers have taken advantage of energy efficiency opportunities relating to more efficient lights, water heaters, appliances, air-conditioners and heaters, and better energy-efficiency labels. The article also assesses the degree that electricity users have become more aware about electricity prices and their levels of consumption, and touches on the connection between rising levels of income and electricity use. It concludes by providing recommendations for how to improve efforts to promote conservation and reduce electricity load growth in Liaoning Province and beyond.

The barriers to energy efficiency in China. Assessing household electricity savings and consumer behavior in Liaoning Province

Energy Technology Data Exchange (ETDEWEB)

Dianshu, Feng; Sovacool, Benjamin K.; Minh Vu, Khuong [Lee Kuan Yew School of Public Policy, Centre on Asia and Globalisation, National University of Singapore, Oei Tiong Ham Building, 469C Bukit Timah Road, Singapore 259772 (Singapore)

2010-02-15

This article investigates the barriers to energy efficiency at the residential sector within one province in China and explores patterns of household electricity consumption. The article presents the results of a survey questionnaire distributed to more than 600 households in Liaoning Province, field research at various Liaoning government agencies, and research interviews of Liaoning government officials to determine the efficacy of their energy efficiency efforts in China. It then investigates the extent that electricity consumers have taken advantage of energy efficiency opportunities relating to more efficient lights, water heaters, appliances, air-conditioners and heaters, and better energy-efficiency labels. The article also assesses the degree that electricity users have become more aware about electricity prices and their levels of consumption, and touches on the connection between rising levels of income and electricity use. It concludes by providing recommendations for how to improve efforts to promote conservation and reduce electricity load growth in Liaoning Province and beyond. (author)

The barriers to energy efficiency in China: Assessing household electricity savings and consumer behavior in Liaoning Province

Energy Technology Data Exchange (ETDEWEB)

Feng Dianshu, E-mail: dianshu@nus.edu.s [Lee Kuan Yew School of Public Policy, Centre on Asia and Globalisation, National University of Singapore, Oei Tiong Ham Building, 469C Bukit Timah Road, Singapore 259772 (Singapore); Sovacool, Benjamin K., E-mail: bsovacool@nus.edu.s [Lee Kuan Yew School of Public Policy, Centre on Asia and Globalisation, National University of Singapore, Oei Tiong Ham Building, 469C Bukit Timah Road, Singapore 259772 (Singapore); Khuong Minh Vu, E-mail: sppkmv@nus.edu.s [Lee Kuan Yew School of Public Policy, Centre on Asia and Globalisation, National University of Singapore, Oei Tiong Ham Building, 469C Bukit Timah Road, Singapore 259772 (Singapore)

2010-02-15

This article investigates the barriers to energy efficiency at the residential sector within one province in China and explores patterns of household electricity consumption. The article presents the results of a survey questionnaire distributed to more than 600 households in Liaoning Province, field research at various Liaoning government agencies, and research interviews of Liaoning government officials to determine the efficacy of their energy efficiency efforts in China. It then investigates the extent that electricity consumers have taken advantage of energy efficiency opportunities relating to more efficient lights, water heaters, appliances, air-conditioners and heaters, and better energy-efficiency labels. The article also assesses the degree that electricity users have become more aware about electricity prices and their levels of consumption, and touches on the connection between rising levels of income and electricity use. It concludes by providing recommendations for how to improve efforts to promote conservation and reduce electricity load growth in Liaoning Province and beyond.

TFTR generator load assessment

International Nuclear Information System (INIS)

Heck, F.M.

1975-10-01

Typical experimental load demands on the TFTR generators are illustrated based on the electrical characteristics of the field coils, the coil leads, the main bus work, the various auxiliary bus work, the rectifiers, and transformers. The generator MW capacities are shown to be adequate for the proposed experimental operations with allowances made for variations in the final designs. The generator MVA capacities are shown to be adequate provided portions of the TF and EF rectifiers are freewheeled at selected times

Scaling relationships between bed load volumes, transport distances, and stream power in steep mountain channels

Science.gov (United States)

Schneider, Johannes M.; Turowski, Jens M.; Rickenmann, Dieter; Hegglin, Ramon; Arrigo, Sabrina; Mao, Luca; Kirchner, James W.

2014-03-01

Bed load transport during storm events is both an agent of geomorphic change and a significant natural hazard in mountain regions. Thus, predicting bed load transport is a central challenge in fluvial geomorphology and natural hazard risk assessment. Bed load transport during storm events depends on the width and depth of bed scour, as well as the transport distances of individual sediment grains. We traced individual gravels in two steep mountain streams, the Erlenbach (Switzerland) and Rio Cordon (Italy), using magnetic and radio frequency identification tags, and measured their bed load transport rates using calibrated geophone bed load sensors in the Erlenbach and a bed load trap in the Rio Cordon. Tracer transport distances and bed load volumes exhibited approximate power law scaling with both the peak stream power and the cumulative stream energy of individual hydrologic events. Bed load volumes scaled much more steeply with peak stream power and cumulative stream energy than tracer transport distances did, and bed load volumes scaled as roughly the third power of transport distances. These observations imply that large bed load transport events become large primarily by scouring the bed deeper and wider, and only secondarily by transporting the mobilized sediment farther. Using the sediment continuity equation, we can estimate the mean effective thickness of the actively transported layer, averaged over the entire channel width and the duration of individual flow events. This active layer thickness also followed approximate power law scaling with peak stream power and cumulative stream energy and ranged up to 0.57 m in the Erlenbach, broadly consistent with independent measurements.

After-hours power status of office equipment and energy use of miscellaneous plug-load equipment

Energy Technology Data Exchange (ETDEWEB)

Roberson, Judy A.; Webber, Carrie A.; McWhinney, Marla C.; Brown, Richard E.; Pinckard, Marageret J.; Busch, John F.

2004-05-27

This research was conducted in support of two branches of the EPA ENERGY STAR program, whose overall goal is to reduce, through voluntary market-based means, the amount of carbon dioxide emitted in the U.S. The primary objective was to collect data for the ENERGY STAR Office Equipment program on the after-hours power state of computers, monitors, printers, copiers, scanners, fax machines, and multi-function devices. We also collected data for the ENERGY STAR Commercial Buildings branch on the types and amounts of miscellaneous plug-load equipment, a significant and growing end use that is not usually accounted for by building energy managers. For most types of miscellaneous equipment, we also estimated typical unit energy consumption in order to estimate total energy consumption of the miscellaneous devices within our sample. This data set is the first of its kind that we know of, and is an important first step in characterizing miscellaneous plug loads in commercial buildings. The main purpose of this study is to supplement and update previous data we collected on the extent to which electronic office equipment is turned off or automatically enters a low power state when not in active use. In addition, it provides data on numbers and types of office equipment, and helps identify trends in office equipment usage patterns. These data improve our estimates of typical unit energy consumption and savings for each equipment type, and enables the ENERGY STAR Office Equipment program to focus future effort on products with the highest energy savings potential. This study expands our previous sample of office buildings in California and Washington DC to include education and health care facilities, and buildings in other states. We report data from sixteen commercial buildings in California, Georgia, and Pennsylvania: four education buildings, two medical buildings, two large offices (> 500 employees each), three medium offices (50-500 employees each), and five small

Assessment of the Fusion Energy Sciences Program. Final Report

International Nuclear Information System (INIS)

2001-01-01

An assessment of the Office of Fusion Energy Sciences (OFES) program with guidance for future program strategy. The overall objective of this study is to prepare an independent assessment of the scientific quality of the Office of Fusion Energy Sciences program at the Department of Energy. The Fusion Science Assessment Committee (FuSAC) has been appointed to conduct this study

Comparative risk assessment of total energy systems

International Nuclear Information System (INIS)

Soerensen, B.

1982-01-01

The paper discusses a methodology for total impact assessment of energy systems, ideally evaluating all the impacts that a given energy system has on the society in which it is imbedded or into which its introduction is being considered. Impacts from the entire energy conversion chain ('fuel cycle' if the system is fuel-based), including energy storage, transport and transmission, as well as the institutions formed in order to manage the system, should be compared on the basis of the energy service provided. A number of impacts are considered, broadly classified as impacts on satisfaction of biological needs, on health, on environment, on social relations and on the structure of society. Further considerations include impacts related to cost and resilience, and, last but not least, impacts on global relations. The paper discusses a number of published energy studies in the light of the comparative impact assessment methodology outlined above. (author)

Life cycle assessment of ocean energy technologies

OpenAIRE

UIHLEIN ANDREAS

2015-01-01

Purpose Oceans offer a vast amount of renewable energy. Tidal and wave energy devices are currently the most advanced conduits of ocean energy. To date, only a few life cycle assessments for ocean energy have been carried out for ocean energy. This study analyses ocean energy devices, including all technologies currently being proposed, in order to gain a better understanding of their environmental impacts and explore how they can contribute to a more sustainable energy supply. Methods...

Optimal planning in a developing industrial microgrid with sensitive loads

Directory of Open Access Journals (Sweden)

M. Naderi

2017-11-01

Full Text Available Computer numerical control (CNC machines are known as sensitive loads in industrial estates. These machines require reliable and qualified electricity in their often long work periods. Supplying these loads with distributed energy resources (DERs in a microgrid (MG can be done as an appropriate solution. The aim of this paper is to analyze the implementation potential of a real and developing MG in Shad-Abad industrial estate, Tehran, Iran. Three MG planning objectives are considered including assurance of sustainable and secure operation of CNC machines as sensitive loads, minimizing the costs of MG construction and operation, and using available capacities to penetrate the highest possible renewable energy sources (RESs which subsequently results in decreasing the air pollutants specially carbon dioxide (CO2. The HOMER (hybrid optimization model for electric renewable software is used to specify the technical feasibility of MG planning and to select the best plan economically and environmentally. Different scenarios are considered in this regard to determine suitable capacity of production participants, and to assess the MG indices such as the reliability.

Assessing the long term impact of phosphorus fertilization on phosphorus loadings using AnnAGNPS.

Science.gov (United States)

Yuan, Yongping; Bingner, Ronald L; Locke, Martin A; Stafford, Jim; Theurer, Fred D

2011-06-01

High phosphorus (P) loss from agricultural fields has been an environmental concern because of potential water quality problems in streams and lakes. To better understand the process of P loss and evaluate the effects of different phosphorus fertilization rates on phosphorus losses, the USDA Annualized AGricultural Non-Point Source (AnnAGNPS) pollutant loading model was applied to the Ohio Upper Auglaize watershed, located in the southern portion of the Maumee River Basin. In this study, the AnnAGNPS model was calibrated using USGS monitored data; and then the effects of different phosphorus fertilization rates on phosphorus loadings were assessed. It was found that P loadings increase as fertilization rate increases, and long term higher P application would lead to much higher P loadings to the watershed outlet. The P loadings to the watershed outlet have a dramatic change after some time with higher P application rate. This dramatic change of P loading to the watershed outlet indicates that a "critical point" may exist in the soil at which soil P loss to water changes dramatically. Simulations with different initial soil P contents showed that the higher the initial soil P content is, the less time it takes to reach the "critical point" where P loadings to the watershed outlet increases dramatically. More research needs to be done to understand the processes involved in the transfer of P between the various stable, active and labile states in the soil to ensure that the model simulations are accurate. This finding may be useful in setting up future P application and management guidelines.

Local forearm and whole-body respiratory quotient in humans after an oral glucose load

DEFF Research Database (Denmark)

Simonsen, L; Bülow, J; Madsen, J

1993-01-01

the glucose load and had not returned to baseline level at the end of the experiment. Whole-body respiratory quotient (RQ) was, on average, 0.80 (SD 0.05) in the baseline condition and increased to a maximum of 0.91 (0.03) and then decreased to baseline level at the end of the experiment. The local forearm.......17) to 0.63 (0.17) 30 min after the glucose load (P glucose load RQ increased to a maximum level at 0.95 (0.22) and decreased then gradually to baseline level. The experiments emphasize several methodological problems in the measurement of local forearm RQ. The whole-body RQ......The effects of an oral glucose load of 75 g on the local forearm and whole-body energy thermogenesis were measured in normal subjects during the 4 h after the glucose intake. Simultaneous assessment of substrate metabolism in the forearm was performed. Energy expenditure (EE) increased after...

Analysis and performance assessment of a multigenerational system powered by Organic Rankine Cycle for a net zero energy house

International Nuclear Information System (INIS)

Hassoun, Anwar; Dincer, Ibrahim

2015-01-01

This paper develops a new Organic Rankine Cycle (ORC) based multigenerational system to meet the demands of a net zero energy building and assesses such a system for an application to a net zero energy house in Lebanon. Solar energy is the prime source for the integrated system to achieve multigeneration to supply electricity, fresh and hot water, seasonal heating and cooling. The study starts by optimizing the power system with and without grid connection. Then, a comprehensive thermodynamic analysis through energy and exergy, and a parametric study to assess the sensitivity and improvements of the overall system are conducted. Furthermore, exergoeconomic analysis and a follow-up optimization study for optimizing the total system cost to the overall system efficiency using genetic algorithm to obtain the optimal design or a set of optimal designs (Pareto Front), are carried out. The present results show that the optimum solar energy system for a total connected load to the house of 90 kWh/day using a combination of ORC, batteries, convertor has a total net present cost of US $52,505.00 (based on the prices in 2013) with a renewable energy fraction of 1. Moreover, the optimization for the same connected load with ORC, batteries and converter configuration with grid connection results in a total net present cost of $50,868.00 (2013) with a renewable energy fraction of 0.992 with 169 kg/yr of CO 2 emissions. In addition, exergoeconomic analysis of the overall system yields a cost of $117,700.00 (2013), and the multi-objective optimization provides the overall exergetic efficiency by 14% at a total system cost increase of $10,500.00 (2013). - Highlights: • To develop a new Organic Rankine Cycle (ORC) based multigenerational system to meet the demands of a net zero energy building. • To perform a comprehensive thermodynamic analysis through energy and exergy approaches. • To apply an exergoeconomic model for exergy-based cost accounting. • To undertake

Estimating energy expenditure during front crawl swimming using accelerometers

DEFF Research Database (Denmark)

Nordsborg, Nikolai Baastrup; Espinosa, Hugo G.; Van Thiel, David H

2014-01-01

The determination of energy expenditure is of major interest in training load and performance assessment. Small, wireless accelerometer units have the potential to characterise energy expenditure during swimming. The correlation between absorbed oxygen versus flume swimming speed and absorbed oxy...

Assessment of Retrofitting Measures for a Large Historic Research Facility Using a Building Energy Simulation Model

Directory of Open Access Journals (Sweden)

Young Tae Chae

2016-06-01

Full Text Available A calibrated building simulation model was developed to assess the energy performance of a large historic research building. The complexity of space functions and operational conditions with limited availability of energy meters makes it hard to understand the end-used energy consumption in detail and to identify appropriate retrofitting options for reducing energy consumption and greenhouse gas (GHG emissions. An energy simulation model was developed to study the energy usage patterns not only at a building level, but also of the internal thermal zones, and system operations. The model was validated using site measurements of energy usage and a detailed audit of the internal load conditions, system operation, and space programs to minimize the discrepancy between the documented status and actual operational conditions. Based on the results of the calibrated model and end-used energy consumption, the study proposed potential energy conservation measures (ECMs for the building envelope, HVAC system operational methods, and system replacement. It also evaluated each ECM from the perspective of both energy and utility cost saving potentials to help retrofitting plan decision making. The study shows that the energy consumption of the building was highly dominated by the thermal requirements of laboratory spaces. Among other ECMs the demand management option of overriding the setpoint temperature is the most cost effective measure.