Peak power reduction and energy efficiency improvement with the superconducting flywheel energy storage in electric railway system

Science.gov (United States)

Lee, Hansang; Jung, Seungmin; Cho, Yoonsung; Yoon, Donghee; Jang, Gilsoo

2013-11-01

This paper proposes an application of the 100 kWh superconducting flywheel energy storage systems to reduce the peak power of the electric railway system. The electric railway systems have high-power characteristics and large amount of regenerative energy during vehicles’ braking. The high-power characteristic makes operating cost high as the system should guarantee the secure capacity of electrical equipment and the low utilization rate of regenerative energy limits the significant energy efficiency improvement. In this paper, it had been proved that the peak power reduction and energy efficiency improvement can be achieved by using 100 kWh superconducting flywheel energy storage systems with the optimally controlled charging or discharging operations. Also, economic benefits had been assessed.

Peak power reduction and energy efficiency improvement with the superconducting flywheel energy storage in electric railway system

Energy Technology Data Exchange (ETDEWEB)

Lee, Hansang, E-mail: hslee80@kiu.ac.kr [School of Railway and Electrical Engineering, Kyungil University, Hayang-eup, Gyeongsan-si, Gyeongsangbuk-do 712-701 (Korea, Republic of); Jung, Seungmin [School of Electrical Engineering, Korea University, Anam-dong, Seongbuk-gu, Seoul 136-712 (Korea, Republic of); Cho, Yoonsung [Department of Electric and Energy Engineering, Catholic University of Daegu, Hayang-eup, Gyeongsan-si, Gyeongsangbuk-do 712-702 (Korea, Republic of); Yoon, Donghee [Department of New and Renewable Energy, Kyungil University, Hayang-eup, Gyeongsangbuk-do 712-701 (Korea, Republic of); Jang, Gilsoo, E-mail: gjang@korea.ac.kr [School of Electrical Engineering, Korea University, Anam-dong, Seongbuk-gu, Seoul 136-712 (Korea, Republic of)

2013-11-15

Highlights: •It is important to develop power and energy management system to save operating cost. •An 100 kWh of SFES is effective to decrease peak power and energy consumption. •Operation cost saving can be achieved using superconducting flywheel energy storage. -- Abstract: This paper proposes an application of the 100 kWh superconducting flywheel energy storage systems to reduce the peak power of the electric railway system. The electric railway systems have high-power characteristics and large amount of regenerative energy during vehicles’ braking. The high-power characteristic makes operating cost high as the system should guarantee the secure capacity of electrical equipment and the low utilization rate of regenerative energy limits the significant energy efficiency improvement. In this paper, it had been proved that the peak power reduction and energy efficiency improvement can be achieved by using 100 kWh superconducting flywheel energy storage systems with the optimally controlled charging or discharging operations. Also, economic benefits had been assessed.

Peak power reduction and energy efficiency improvement with the superconducting flywheel energy storage in electric railway system

International Nuclear Information System (INIS)

Lee, Hansang; Jung, Seungmin; Cho, Yoonsung; Yoon, Donghee; Jang, Gilsoo

2013-01-01

Highlights: •It is important to develop power and energy management system to save operating cost. •An 100 kWh of SFES is effective to decrease peak power and energy consumption. •Operation cost saving can be achieved using superconducting flywheel energy storage. -- Abstract: This paper proposes an application of the 100 kWh superconducting flywheel energy storage systems to reduce the peak power of the electric railway system. The electric railway systems have high-power characteristics and large amount of regenerative energy during vehicles’ braking. The high-power characteristic makes operating cost high as the system should guarantee the secure capacity of electrical equipment and the low utilization rate of regenerative energy limits the significant energy efficiency improvement. In this paper, it had been proved that the peak power reduction and energy efficiency improvement can be achieved by using 100 kWh superconducting flywheel energy storage systems with the optimally controlled charging or discharging operations. Also, economic benefits had been assessed

Energy-Efficient Power Allocation for Cognitive MIMO Channels

KAUST Repository

Sboui, Lokman; Rezki, Zouheir; Salem, Ahmed Sultan; Alouini, Mohamed-Slim

2017-01-01

achieves at least 95% of the optimal performance. In addition, we show that adopting more antennas is more energy efficient for a given power budget. Finally, we show that the interference threshold has a significant effect on both the EE and the spectral

Thermodynamic, energy efficiency, and power density analysis of reverse electrodialysis power generation with natural salinity gradients

NARCIS (Netherlands)

Yip, N.Y.; Vermaas, D.A.; Nijmeijer, K.; Elimelech, M.

2014-01-01

Reverse electrodialysis (RED) can harness the Gibbs free energy of mixing when fresh river water flows into the sea for sustainable power generation. In this study, we carry out a thermodynamic and energy efficiency analysis of RED power generation, and assess the membrane power density. First, we

Energy-Efficient Resource and Power Allocation for Underlay Multicast Device-to-Device Transmission

Directory of Open Access Journals (Sweden)

Fan Jiang

2017-11-01

Full Text Available In this paper, we present an energy-efficient resource allocation and power control scheme for D2D (Device-to-Device multicasting transmission. The objective is to maximize the overall energy-efficiency of D2D multicast clusters through effective resource allocation and power control schemes, while considering the quality of service (QoS requirements of both cellular users (CUs and D2D clusters. We first build the optimization model and a heuristic resource and power allocation algorithm is then proposed to solve the energy-efficiency problem with less computational complexity. Numerical results indicate that the proposed algorithm outperforms existing schemes in terms of throughput per energy consumption.

Indicators System Creation For The Energy Efficiency Benchmarking Of Municipal Power System Facilities

Directory of Open Access Journals (Sweden)

Davydenko L.V.

2015-04-01

Full Text Available The issues of the dataware of the comparative analysis procedure (benchmarking for municipal power system facilities energy efficiency level estimation with a view of the hierarchical structure of the heat supply system are considered. The aim of the paper is the system of indicators formation for characterizing the efficiency of energy usage as on objects on lowest so on highest levels of power systems, proceeding from features of their functioning. Benchmarking methodology allows carrying out the estimation of energy efficiency level on the base of a plurality of parameters without their generalization in one indicator, but requires ensuring their comparability. Using the methodology of available statistical information that did not require deep specification and additional inspection structuring objectives and tasks of energy efficiency estimation problem has been proposed for ensuring the opportunity of benchmarking procedure implementation. This makes it possible to form the subset of indicators that ensure enough specification of the object of study, taking into account the degree of abstraction for every hierarchical level or sub problem. For a comparative analysis of energy using efficiency in municipal power systems at the highest levels of the hierarchy a plurality of indicators of the energy efficiency has been formed. Indicators have been determined with consideration of the structural elements of heat supply systems, but allowing taking into account the efficiency of the initial state of the objects, their functioning, and the questions of energy resources accounting organization. Usage of the proposed indicators provides implementation of energy using efficiency monitoring in the municipal power system and allows getting complete overview of the problem.

International comparisons of energy efficiency in power, steel, and cement industries

International Nuclear Information System (INIS)

Oda, Junichiro; Akimoto, Keigo; Tomoda, Toshimasa; Nagashima, Miyuki; Wada, Kenichi; Sano, Fuminori

2012-01-01

Industrial energy efficiency is of paramount importance both for conserving energy resources and reducing CO 2 emissions. In this paper, we compare specific energy consumption among countries in fossil power generation, steel, and cement sectors. The evaluations were conducted using common system boundaries, allocation, and calculation methods. In addition, we disaggregate within sectors, such as with blast furnace–basic oxygen furnace (BF–BOF) steel and scrap-based electric arc furnace (Scrap-EAF) steel. The results reveal that characteristics vary by sub-sector. Regional differences in specific energy consumption are relatively large in the power, BF–BOF steel, and cement sectors. For coal power generation and BF–BOF steel production, continual maintenance and rehabilitation are of key importance. We confirm these key factors identified in the previous work on our estimated numerical values. In BF–BOF steel production, corrections for hot metal ratios (pig iron production per unit of BOF crude steel production) and quality of raw materials have a large effect on the apparent specific energy consumption. Available data is not yet sufficient for straightforward evaluation of the steel and cement sectors. - Highlights: ► We compare energy efficiency among countries in power, steel, and cement sectors. ► In steel and cement sectors, the results are provided in terms of specific energy consumption (GJ/ton of product). ► We distinguish BOF steel and EAF steel. ► New installation and continual maintenance are the key for energy efficiency. ► Corrections have a large impact on apparent specific energy consumption.

Thermal power plant efficiency enhancement with Ocean Thermal Energy Conversion

International Nuclear Information System (INIS)

Soto, Rodrigo; Vergara, Julio

2014-01-01

In addition to greenhouse gas emissions, coastal thermal power plants would gain further opposition due to their heat rejection distressing the local ecosystem. Therefore, these plants need to enhance their thermal efficiency while reducing their environmental offense. In this study, a hybrid plant based on the principle of Ocean Thermal Energy Conversion was coupled to a 740 MW coal-fired power plant project located at latitude 28°S where the surface to deepwater temperature difference would not suffice for regular OTEC plants. This paper presents the thermodynamical model to assess the overall efficiency gained by adopting an ammonia Rankine cycle plus a desalinating unit, heated by the power plant condenser discharge and refrigerated by cold deep seawater. The simulation allowed us to optimize a system that would finally enhance the plant power output by 25–37 MW, depending on the season, without added emissions while reducing dramatically the water temperature at discharge and also desalinating up to 5.8 million tons per year. The supplemental equipment was sized and the specific emissions reduction was estimated. We believe that this approach would improve the acceptability of thermal and nuclear power plant projects regardless of the plant location. -- Highlights: • An Ocean Thermal Energy Conversion hybrid plant was designed. • The waste heat of a power plant was delivered as an OTEC heat source. • The effect of size and operating conditions on plant efficiency were studied. • The OTEC implementation in a Chilean thermal power plant was evaluated. • The net efficiency of the thermal power plant was increased by 1.3%

Energy-efficient power control for OFDMA cellular networks

KAUST Repository

Sboui, Lokman

2016-12-24

In this paper, we study the energy efficiency (EE) of orthogonal frequency-division multiple access (OFDMA) cellular networks. Our objective is to present a power allocation scheme that maximizes the EE of downlink communications. We propose a novel explicit expression of the optimal power allocation to each subcarrier. We also present the power control when the transmit power is limited by power budget constraint or/and minimal rate constraint and we highlight the occurrence of some transmission outage events depending on the constraints\\' parameters. In the numerical results, we show that our proposed power control improves the EE especially at high power budget regime and low minimal rate regime. In addition, we show that having a higher number of subcarriers enhances the OFDMA EE.

Energy Efficient Monitoring for Intrusion Detection in Battery-Powered Wireless Mesh Networks

KAUST Repository

Hassanzadeh, Amin; Stoleru, Radu; Shihada, Basem

2011-01-01

in such environments battery-powered mesh routers, operating in an energy efficient manner, are required. To the best of our knowledge, the impact of energy efficient solutions, e.g., involving duty-cycling, on WMN intrusion detection systems, which require continuous

Energy balance and efficiency of power stations with a pulsed Tokamak reactor

International Nuclear Information System (INIS)

Davenport, P.A.; Mitchell, J.T.D.; Darvas, J.; Foerster, S.; Sack, B.

1976-06-01

The energy balance of a fusion power station based on the TOKAMAK concept is examined with the aid of a model comprising three distinct elements: the reactor, the energy converter and the reactor operation equipment. The efficiency of each element is expressed in terms of the various energy flows and the product of these efficiencies gives the net station efficiency. The analysis takes account of pulsed operation and has general applicability. Numerical values for the net station efficiency are derived from detailed estimates of the energy flows for a TOKAMAK reactor and its auxiliary equipment operating with advanced energy converters. The derivation of these estimates is given in eleven appendices. The calculated station efficiencies span ranges similar to those quoted for the current generation of fission reactors, though lower than those predicted for HTGR and LMFBR stations. Credible parameter domains for pulsed TOKAMAK operation are firmly delineated and factors inimical to improved performance are indicated. It is concluded that the net thermal efficiency of a TOKAMAK reactor power station based on present designs and using advanced thermal converters will be approximately 0.3 and is unlikely to exceed 0.33. (orig.) [de

Energy efficient refrigeration and flexible power consumption in a smart grid

Energy Technology Data Exchange (ETDEWEB)

Gybel Hovgaard, T.; Larsen, Lars F.S. (Danfoss Refrigeration and A/C Controls, Nordborg (Denmark)); Halvgaard, R.; Bagterp Joergensen, J. (Technical Univ. of Denmark (DTU). DTU Informatics, Kgs. Lyngby (Denmark))

2011-05-15

Refrigeration and heating systems consume substantial amounts of energy worldwide. However, due to the thermal capacity there is a potential for storing 'coldness' or heat in the system. This feature allows for implementation of different load shifting and shedding strategies in order to optimize the operation energywise, but without compromising the original cooling and indoor climate quality. In this work we investigate the potential of such a strategy and its ability to significantly lower the cost related to operating systems such as supermarket refrigeration and heat pumps for residential houses. With modern Economic Model Predictive Control (MPC) methods we make use of weather forecasts and predictions of varying electricity prices to apply more load to the system when the thermodynamic cycle is most efficient, and to consume larger shares of the electricity when the demand and thereby the prices are low. The ability to adjust power consumption according to the demands on the power grid is a highly wanted feature in a future Smart Grid. Efficient utilization of greater amounts of renewable energy calls for solutions to control the power consumption such that it increases when an energy surplus is available and decreases when there is a shortage. This should happen almost instantly to accommodate intermittent energy sources as e.g. wind turbines. We expect our power management solution to render systems with thermal storage capabilities suitable for flexible power consumption. The aggregation of several units will contribute significantly to the shedding of total electricity demand. Using small case studies we demonstrate the potential for utilizing daily variations to deliver a power efficient cooling or heating and for the implementation of Virtual Power Plants in Smart Grid scenarios. (Author)

A novel MPPT method for enhancing energy conversion efficiency taking power smoothing into account

International Nuclear Information System (INIS)

Liu, Jizhen; Meng, Hongmin; Hu, Yang; Lin, Zhongwei; Wang, Wei

2015-01-01

Highlights: • We discuss the disadvantages of conventional OTC MPPT method. • We study the relationship between enhancing efficiency and power smoothing. • The conversion efficiency is enhanced and the volatility of power is suppressed. • Small signal analysis is used to verify the effectiveness of proposed method. - Abstract: With the increasing capacity of wind energy conversion system (WECS), the rotational inertia of wind turbine is becoming larger. And the efficiency of energy conversion is significantly reduced by the large inertia. This paper proposes a novel maximum power point tracking (MPPT) method to enhance the efficiency of energy conversion for large-scale wind turbine. Since improving the efficiency may increase the fluctuations of output power, power smoothing is considered as the second control objective. A T-S fuzzy inference system (FIS) is adapted to reduce the fluctuations according to the volatility of wind speed and accelerated rotor speed by regulating the compensation gain. To verify the effectiveness, stability and good dynamic performance of the new method, mechanism analyses, small signal analyses, and simulation studies are carried out based on doubly-fed induction generator (DFIG) wind turbine, respectively. Study results show that both the response speed and the efficiency of proposed method are increased. In addition, the extra fluctuations of output power caused by the high efficiency are reduced effectively by the proposed method with FIS

Optimal Energy Efficiency Fairness of Nodes in Wireless Powered Communication Networks.

Science.gov (United States)

Zhang, Jing; Zhou, Qingjie; Ng, Derrick Wing Kwan; Jo, Minho

2017-09-15

In wireless powered communication networks (WPCNs), it is essential to research energy efficiency fairness in order to evaluate the balance of nodes for receiving information and harvesting energy. In this paper, we propose an efficient iterative algorithm for optimal energy efficiency proportional fairness in WPCN. The main idea is to use stochastic geometry to derive the mean proportionally fairness utility function with respect to user association probability and receive threshold. Subsequently, we prove that the relaxed proportionally fairness utility function is a concave function for user association probability and receive threshold, respectively. At the same time, a sub-optimal algorithm by exploiting alternating optimization approach is proposed. Through numerical simulations, we demonstrate that our sub-optimal algorithm can obtain a result close to optimal energy efficiency proportional fairness with significant reduction of computational complexity.

Management Index Systems and Energy Efficiency Diagnosis Model for Power Plant: Cases in China

Directory of Open Access Journals (Sweden)

Jing-Min Wang

2016-01-01

Full Text Available In recent years, the energy efficiency of thermal power plant largely contributes to that of the industry. A thorough understanding of influencing factors, as well as the establishment of scientific and comprehensive diagnosis model, plays a key role in the operational efficiency and competitiveness for the thermal power plant. Referring to domestic and abroad researches towards energy efficiency management, based on Cloud model and data envelopment analysis (DEA model, a qualitative and quantitative index system and a comprehensive diagnostic model (CDM are construed. To testify rationality and usability of CDM, case studies of large-scaled Chinese thermal power plants have been conducted. In this case, CDM excavates such qualitative factors as technology, management, and so forth. The results shows that, compared with conventional model, which only considered production running parameters, the CDM bears better adaption to reality. It can provide entities with efficient instruments for energy efficiency diagnosis.

A Biologically-Inspired Power Control Algorithm for Energy-Efficient Cellular Networks

Directory of Open Access Journals (Sweden)

Hyun-Ho Choi

2016-03-01

Full Text Available Most of the energy used to operate a cellular network is consumed by a base station (BS, and reducing the transmission power of a BS can therefore afford a substantial reduction in the amount of energy used in a network. In this paper, we propose a distributed transmit power control (TPC algorithm inspired by bird flocking behavior as a means of improving the energy efficiency of a cellular network. Just as each bird in a flock attempts to match its velocity with the average velocity of adjacent birds, in the proposed algorithm, each mobile station (MS in a cell matches its rate with the average rate of the co-channel MSs in adjacent cells by controlling the transmit power of its serving BS. We verify that this bio-inspired TPC algorithm using a local rate-average process achieves an exponential convergence and maximizes the minimum rate of the MSs concerned. Simulation results show that the proposed TPC algorithm follows the same convergence properties as the flocking algorithm and also effectively reduces the power consumption at the BSs while maintaining a low outage probability as the inter-cell interference increases; in so doing, it significantly improves the energy efficiency of a cellular network.

Energy-Efficient Optimal Power Allocation in Integrated Wireless Sensor and Cognitive Satellite Terrestrial Networks.

Science.gov (United States)

Shi, Shengchao; Li, Guangxia; An, Kang; Gao, Bin; Zheng, Gan

2017-09-04

This paper proposes novel satellite-based wireless sensor networks (WSNs), which integrate the WSN with the cognitive satellite terrestrial network. Having the ability to provide seamless network access and alleviate the spectrum scarcity, cognitive satellite terrestrial networks are considered as a promising candidate for future wireless networks with emerging requirements of ubiquitous broadband applications and increasing demand for spectral resources. With the emerging environmental and energy cost concerns in communication systems, explicit concerns on energy efficient resource allocation in satellite networks have also recently received considerable attention. In this regard, this paper proposes energy-efficient optimal power allocation schemes in the cognitive satellite terrestrial networks for non-real-time and real-time applications, respectively, which maximize the energy efficiency (EE) of the cognitive satellite user while guaranteeing the interference at the primary terrestrial user below an acceptable level. Specifically, average interference power (AIP) constraint is employed to protect the communication quality of the primary terrestrial user while average transmit power (ATP) or peak transmit power (PTP) constraint is adopted to regulate the transmit power of the satellite user. Since the energy-efficient power allocation optimization problem belongs to the nonlinear concave fractional programming problem, we solve it by combining Dinkelbach's method with Lagrange duality method. Simulation results demonstrate that the fading severity of the terrestrial interference link is favorable to the satellite user who can achieve EE gain under the ATP constraint comparing to the PTP constraint.

Energy-Efficient Power Allocation for Underlay Cognitive Radio Systems

KAUST Repository

Sboui, Lokman

2015-09-01

We present a power allocation framework for spectrum sharing Cognitive Radio (CR) systems based on maximizing the energy efficiency (EE). First, we show that the relation between the EE and the spectral efficiency (SE) is strictly increasing in contrast with the SE-EE trade-off discussed in the literature. We also solve a non-convex problem and explicitly derive the optimal power for the proposed average EE under either a peak or an average power constraint. We apply our results to the underlay CR systems where the power is limited by an additional interference constraint. When the instantaneous channel is not available, we provide a necessary and sufficient condition for the optimal power and present a simple sub-optimal power. In the numerical results, we show that the proposed EE corresponds to a higher SE at mid-range and high power regime compared to the classical EE. We also show that the sup-optimal solution is very close to the optimal solution. In addition, we deduce that the absence of instantaneous CSI affects the EE and the SE at high power regime compared to full CSI. In the CR context, we show that the interference threshold has a minimal effect on the EE compared to the SE.

Energy-Efficient Power Allocation for Underlay Cognitive Radio Systems

KAUST Repository

Sboui, Lokman; Rezki, Zouheir; Alouini, Mohamed-Slim

2015-01-01

We present a power allocation framework for spectrum sharing Cognitive Radio (CR) systems based on maximizing the energy efficiency (EE). First, we show that the relation between the EE and the spectral efficiency (SE) is strictly increasing in contrast with the SE-EE trade-off discussed in the literature. We also solve a non-convex problem and explicitly derive the optimal power for the proposed average EE under either a peak or an average power constraint. We apply our results to the underlay CR systems where the power is limited by an additional interference constraint. When the instantaneous channel is not available, we provide a necessary and sufficient condition for the optimal power and present a simple sub-optimal power. In the numerical results, we show that the proposed EE corresponds to a higher SE at mid-range and high power regime compared to the classical EE. We also show that the sup-optimal solution is very close to the optimal solution. In addition, we deduce that the absence of instantaneous CSI affects the EE and the SE at high power regime compared to full CSI. In the CR context, we show that the interference threshold has a minimal effect on the EE compared to the SE.

Highly efficient solutions for smart and bulk power transmission of 'green energy'

Energy Technology Data Exchange (ETDEWEB)

Breuer, Wilfried; Retzmann, Dietmar; Uecker, Karl

2010-09-15

Environmental constraints, loss minimization and CO2 reduction will play an increasingly more important role in future. Security and sustainability of power supply as well as economic efficiency needs application of advanced technologies. Innovative solutions with HVDC (High Voltage Direct Current) and FACTS (Flexible AC Transmission Systems) have the potential to cope with these challenges. They provide the features which are necessary to avoid technical problems in power systems, they increase the transmission capacity and system stability very efficiently and help prevent cascading outages. Furthermore, they are essential for Grid Access of Renewable Energy Sources such as Hydro, Wind and Solar-Energy.

A self-powered piezoelectric energy harvesting interface circuit with efficiency-enhanced P-SSHI rectifier

Science.gov (United States)

Liu, Lianxi; Pang, Yanbo; Yuan, Wenzhi; Zhu, Zhangming; Yang, Yintang

2018-04-01

The key to self-powered technique is initiative to harvest energy from the surrounding environment. Harvesting energy from an ambient vibration source utilizing piezoelectrics emerged as a popular method. Efficient interface circuits become the main limitations of existing energy harvesting techniques. In this paper, an interface circuit for piezoelectric energy harvesting is presented. An active full bridge rectifier is adopted to improve the power efficiency by reducing the conduction loss on the rectifying path. A parallel synchronized switch harvesting on inductor (P-SSHI) technique is used to improve the power extraction capability from piezoelectric harvester, thereby trying to reach the theoretical maximum output power. An intermittent power management unit (IPMU) and an output capacitor-less low drop regulator (LDO) are also introduced. Active diodes (AD) instead of traditional passive ones are used to reduce the voltage loss over the rectifier, which results in a good power efficiency. The IPMU with hysteresis comparator ensures the interface circuit has a large transient output power by limiting the output voltage ranges from 2.2 to 2 V. The design is fabricated in a SMIC 0.18 μm CMOS technology. Simulation results show that the flipping efficiency of the P-SSHI circuit is over 80% with an off-chip inductor value of 820 μH. The output power the proposed rectifier can obtain is 44.4 μW, which is 6.7× improvement compared to the maximum output power of a traditional rectifier. Both the active diodes and the P-SSHI help to improve the output power of the proposed rectifier. LDO outputs a voltage of 1.8 V with the maximum 90% power efficiency. The proposed P-SSHI rectifier interface circuit can be self-powered without the need for additional power supply. Project supported by the National Natural Science Foundation of China (Nos. 61574103, U1709218) and the Key Research and Development Program of Shaanxi Province (No. 2017ZDXM-GY-006).

Total-Factor Energy Efficiency (TFEE Evaluation on Thermal Power Industry with DEA, Malmquist and Multiple Regression Techniques

Directory of Open Access Journals (Sweden)

Jin-Peng Liu

2017-07-01

Full Text Available Under the background of a new round of power market reform, realizing the goals of energy saving and emission reduction, reducing the coal consumption and ensuring the sustainable development are the key issues for thermal power industry. With the biggest economy and energy consumption scales in the world, China should promote the energy efficiency of thermal power industry to solve these problems. Therefore, from multiple perspectives, the factors influential to the energy efficiency of thermal power industry were identified. Based on the economic, social and environmental factors, a combination model with Data Envelopment Analysis (DEA and Malmquist index was constructed to evaluate the total-factor energy efficiency (TFEE in thermal power industry. With the empirical studies from national and provincial levels, the TFEE index can be factorized into the technical efficiency index (TECH, the technical progress index (TPCH, the pure efficiency index (PECH and the scale efficiency index (SECH. The analysis showed that the TFEE was mainly determined by TECH and PECH. Meanwhile, by panel data regression model, unit coal consumption, talents and government supervision were selected as important indexes to have positive effects on TFEE in thermal power industry. In addition, the negative indexes, such as energy price and installed capacity, were also analyzed to control their undesired effects. Finally, considering the analysis results, measures for improving energy efficiency of thermal power industry were discussed widely, such as strengthening technology research and design (R&D, enforcing pollutant and emission reduction, distributing capital and labor rationally and improving the government supervision. Relative study results and suggestions can provide references for Chinese government and enterprises to enhance the energy efficiency level.

Power recovery method for testing the efficiency of the ECD of an integrated generation unit for offshore wind power and ocean wave energy

Institute of Scientific and Technical Information of China (English)

CHEN WeiXing; GAO Feng; MENG XiangDun; REN AnYe; HU Yan

2017-01-01

Offshore wind power and ocean wave energy are clean,renewable and rich resources.The integrated generation unit for the two kinds of energy is introduced.The energy conversion device (ECD) is utilized to convert the mechanical energy absorbed from the wind power and wave energy into the hydraulic energy,the conversion efficiency of which is significant.In this paper,a power recovery method for testing the efficiency of the ECD is proposed.A simulation desktop is developed to validate the proposed method.The efficiency of the ECD is influenced by the hydraulic cylinders and the mechanical transmission.Here,the static efficiency of the hydraulic cylinders of the ECD is tested first.The results show that the static mechanical efficiency is about 95 ％ and that the volumetric efficiency is over 99％.To test the effects induced by the mechanical transmission of the ECD,each hydraulic cylinder of the ECD is substituted with two springs.Then the power loss of the ECDM under different rotational speeds is obtained.Finally,a test platform is built and the efficiency of the ECD under different rotational speeds and pressures is obtained.The results show that the efficiency is about 80％.

Design of Low Power Multiplier with Energy Efficient Full Adder Using DPTAAL

Directory of Open Access Journals (Sweden)

A. Kishore Kumar

2013-01-01

Full Text Available Asynchronous adiabatic logic (AAL is a novel lowpower design technique which combines the energy saving benefits of asynchronous systems with adiabatic benefits. In this paper, energy efficient full adder using double pass transistor with asynchronous adiabatic logic (DPTAAL is used to design a low power multiplier. Asynchronous adiabatic circuits are very low power circuits to preserve energy for reuse, which reduces the amount of energy drawn directly from the power supply. In this work, an 8×8 multiplier using DPTAAL is designed and simulated, which exhibits low power and reliable logical operations. To improve the circuit performance at reduced voltage level, double pass transistor logic (DPL is introduced. The power results of the proposed multiplier design are compared with the conventional CMOS implementation. Simulation results show significant improvement in power for clock rates ranging from 100 MHz to 300 MHz.

Finding the Energy Efficient Curve: Gate Sizing for Minimum Power under Delay Constraints

Directory of Open Access Journals (Sweden)

Yoni Aizik

2011-01-01

Full Text Available A design scenario examined in this paper assumes that a circuit has been designed initially for high speed, and it is redesigned for low power by downsizing of the gates. In recent years, as power consumption has become a dominant issue, new optimizations of circuits are required for saving energy. This is done by trading off some speed in exchange for reduced power. For each feasible speed, an optimization problem is solved in this paper, finding new sizes for the gates such that the circuit satisfies the speed goal while dissipating minimal power. Energy/delay gain (EDG is defined as a metric to quantify the most efficient tradeoff. The EDG of the circuit is evaluated for a range of reduced circuit speeds, and the power-optimal gate sizes are compared with the initial sizes. Most of the energy savings occur at the final stages of the circuits, while the largest relative downsizing occurs in middle stages. Typical tapering factors for power efficient circuits are larger than those for speed-optimal circuits. Signal activity and signal probability affect the optimal gate sizes in the combined optimization of speed and power.

Energy-Efficient Power Allocation for Fixed-Gain Amplify-and-Forward Relay Networks with Partial Channel State Information

KAUST Repository

Zafar, Ammar; Alouini, Mohamed-Slim; Chen, Yunfei; Radaydeh, Redha M.

2012-01-01

In this letter, energy-efficient transmission and power allocation for fixed-gain amplify-and-forward relay networks with partial channel state information (CSI) are studied. In the energy-efficiency problem, the total power consumed is minimized

IMPACT OF THE COLD END OPERATING CONDITIONS ON ENERGY EFFICIENCY OF THE STEAM POWER PLANTS

Directory of Open Access Journals (Sweden)

Slobodan Laković

2010-01-01

Full Text Available The conventional steam power plant working under the Rankine Cycle and the steam condenser as a heat sink and the steam boiler as a heat source have the same importance for the power plant operating process. Energy efficiency of the coal fired power plant strongly depends on its turbine-condenser system operation mode. For the given thermal power plant configuration, cooling water temperature or/and flow rate change generate alterations in the condenser pressure. Those changes have great influence on the energy efficiency of the plant. This paper focuses on the influence of the cooling water temperature and flow rate on the condenser performance, and thus on the specific heat rate of the coal fired plant and its energy efficiency. Reference plant is working under turbine-follow mode with an open cycle cooling system. Analysis is done using thermodynamic theory, in order to define heat load dependence on the cooling water temperature and flow rate. Having these correlations, for given cooling water temperature it is possible to determine optimal flow rate of the cooling water in order to achieve an optimal condensing pressure, and thus, optimal energy efficiency of the plant. Obtained results could be used as useful guidelines in improving existing power plants performances and also in design of the new power plants.

Waste-to-energy advanced cycles and new design concepts for efficient power plants

CERN Document Server

Branchini, Lisa

2015-01-01

This book provides an overview of state-of-the-art technologies for energy conversion from waste, as well as a much-needed guide to new and advanced strategies to increase Waste-to-Energy (WTE) plant efficiency. Beginning with an overview of municipal solid waste production and disposal, basic concepts related to Waste-To-Energy conversion processes are described, highlighting the most relevant aspects impacting the thermodynamic efficiency of WTE power plants. The pervasive influences of main steam cycle parameters and plant configurations on WTE efficiency are detailed and quantified. Advanc

Energy-Efficient Power Allocation for UAV Cognitive Radio Systems

KAUST Repository

Sboui, Lokman

2018-02-12

We study the deployment of unmanned aerial vehicles (UAV) based cognitive system in an area covered by the primary network (PN). An UAV shares the spectrum of the PN and aims to maximize its energy efficiency (EE) by optimizing the transmit power. We focus on the case where the UAV simultaneously communicates with the ground receiver (G), under interference limitation, and with another relaying UAV (A), with a minimal required rate. We analytically develop the power allocation framework that maximizes the EE subject to power budget, interference, and minimal rate constraints. In the numerical results, we show that the minimal rate may cause a transmission outage at low power budget values. We also highlighted the existence of optimal altitudes given the UAV location with respect to the different other terminals.

Energy-Efficient Power Allocation for UAV Cognitive Radio Systems

KAUST Repository

Sboui, Lokman; Ghazzai, Hakim; Rezki, Zouheir; Alouini, Mohamed-Slim

2018-01-01

We study the deployment of unmanned aerial vehicles (UAV) based cognitive system in an area covered by the primary network (PN). An UAV shares the spectrum of the PN and aims to maximize its energy efficiency (EE) by optimizing the transmit power. We focus on the case where the UAV simultaneously communicates with the ground receiver (G), under interference limitation, and with another relaying UAV (A), with a minimal required rate. We analytically develop the power allocation framework that maximizes the EE subject to power budget, interference, and minimal rate constraints. In the numerical results, we show that the minimal rate may cause a transmission outage at low power budget values. We also highlighted the existence of optimal altitudes given the UAV location with respect to the different other terminals.

Energy-Efficiency Analysis of Per-Subcarrier Antenna Selection with Peak-Power Reduction in MIMO-OFDM Wireless Systems

Directory of Open Access Journals (Sweden)

Ngoc Phuc Le

2014-01-01

Full Text Available The use of per-subcarrier antenna subset selection in OFDM wireless systems offers higher system capacity and/or improved link reliability. However, the implementation of the conventional per-subcarrier selection scheme may result in significant fluctuations of the average power and peak power across antennas, which affects the potential benefits of the system. In this paper, power efficiency of high-power amplifiers and energy efficiency in per-subcarrier antenna selection MIMO-OFDM systems are investigated. To deliver the maximum overall power efficiency, we propose a two-step strategy for data-subcarrier allocation. This strategy consists of an equal allocation of data subcarriers based on linear optimization and peak-power reduction via cross-antenna permutations. For analysis, we derive the CCDF (complementary cumulative distribution function of the power efficiency as well as the analytical expressions of the average power efficiency. It is proved from the power-efficiency perspective that the proposed allocation scheme outperforms the conventional scheme. We also show that the improvement in the power efficiency translates into an improved capacity and, in turn, increases energy efficiency of the proposed system. Simulation results are provided to validate our analyses.

Comparison of energy efficiency and power density in pressure retarded osmosis and reverse electrodialysis.

Science.gov (United States)

Yip, Ngai Yin; Elimelech, Menachem

2014-09-16

Pressure retarded osmosis (PRO) and reverse electrodialysis (RED) are emerging membrane-based technologies that can convert chemical energy in salinity gradients to useful work. The two processes have intrinsically different working principles: controlled mixing in PRO is achieved by water permeation across salt-rejecting membranes, whereas RED is driven by ion flux across charged membranes. This study compares the energy efficiency and power density performance of PRO and RED with simulated technologically available membranes for natural, anthropogenic, and engineered salinity gradients (seawater-river water, desalination brine-wastewater, and synthetic hypersaline solutions, respectively). The analysis shows that PRO can achieve both greater efficiencies (54-56%) and higher power densities (2.4-38 W/m(2)) than RED (18-38% and 0.77-1.2 W/m(2)). The superior efficiency is attributed to the ability of PRO membranes to more effectively utilize the salinity difference to drive water permeation and better suppress the detrimental leakage of salts. On the other hand, the low conductivity of currently available ion exchange membranes impedes RED ion flux and, thus, constrains the power density. Both technologies exhibit a trade-off between efficiency and power density: employing more permeable but less selective membranes can enhance the power density, but undesired entropy production due to uncontrolled mixing increases and some efficiency is sacrificed. When the concentration difference is increased (i.e., natural → anthropogenic → engineered salinity gradients), PRO osmotic pressure difference rises proportionally but not so for RED Nernst potential, which has logarithmic dependence on the solution concentration. Because of this inherently different characteristic, RED is unable to take advantage of larger salinity gradients, whereas PRO power density is considerably enhanced. Additionally, high solution concentrations suppress the Donnan exclusion effect of the

Incorporating energy efficiency into electric power transmission planning: A western United States case study

International Nuclear Information System (INIS)

Barbose, Galen L.; Sanstad, Alan H.; Goldman, Charles A.

2014-01-01

Driven by system reliability goals and the need to integrate significantly increased renewable power generation, long-range, bulk-power transmission planning processes in the United States are undergoing major changes. At the same time, energy efficiency is an increasing share of the electricity resource mix in many regions, and has become a centerpiece of many utility resource plans and state policies as a means of meeting electricity demand, complementing supply-side sources, and reducing carbon dioxide emissions from the electric power system. The paper describes an innovative project in the western United States to explicitly incorporate end-use efficiency into load forecasts – projections of electricity consumption and demand – that are a critical input into transmission planning and transmission planning studies. Institutional and regulatory background and context are reviewed, along with a detailed discussion of data sources and analytical procedures used to integrate efficiency into load forecasts. The analysis is intended as a practical example to illustrate the kinds of technical and institutional issues that must be addressed in order to incorporate energy efficiency into regional transmission planning activities. - Highlights: • Incorporating energy efficiency into electric power transmission planning is an emergent analytical and policy priority. • A new methodology for this purpose was developed and applied in the western U.S. transmission system. • Efficiency scenarios were created and incorporated into multiple load forecasts. • Aggressive deployment of efficiency policies and programs can significantly reduce projected load. • The approach is broadly applicable in long-range transmission planning

Research of waste heat energy efficiency for absorption heat pump recycling thermal power plant circulating water

Science.gov (United States)

Zhang, Li; Zhang, Yu; Zhou, Liansheng; E, Zhijun; Wang, Kun; Wang, Ziyue; Li, Guohao; Qu, Bin

2018-02-01

The waste heat energy efficiency for absorption heat pump recycling thermal power plant circulating water has been analyzed. After the operation of heat pump, the influences on power generation and heat generation of unit were taken into account. In the light of the characteristics of heat pump in different operation stages, the energy efficiency of heat pump was evaluated comprehensively on both sides of benefits belonging to electricity and benefits belonging to heat, which adopted the method of contrast test. Thus, the reference of energy efficiency for same type projects was provided.

Energy Efficiency Roadmap for Uganda, Making Energy Efficiency Count. Executive Summary

Energy Technology Data Exchange (ETDEWEB)

de la Rue du Can, Stephane; Pudleiner, David; Jones, David; Khan, Aleisha

2017-06-15

Like many countries in Sub-Saharan Africa, Uganda has focused its energy sector investments largely on increasing energy access by increasing energy supply. The links between energy efficiency and energy access, the importance of energy efficiency in new energy supply, and the multiple benefits of energy efficiency for the level and quality of energy available, have been largely overlooked. Implementing energy efficiency in parallel with expanding both the electricity grid and new clean energy generation reduces electricity demand and helps optimize the power supply so that it can serve more customers reliably at minimum cost. Ensuring efficient appliances are incorporated into energy access efforts provides improved energy services to customers. Energy efficiency is an important contributor to access to modern energy. This Energy Efficiency Roadmap for Uganda (Roadmap) is a response to the important role that electrical energy efficiency can play in meeting Uganda’s energy goals. Power Africa and the United Nations Sustainable Energy for All (SEforALL) initiatives collaborated with more than 24 stakeholders in Uganda to develop this document. The document estimates that if the most efficient technologies on the market were adopted, 2,224 gigawatt hours could be saved in 2030 across all sectors, representing 31% of the projected load. This translates into 341 megawatts of peak demand reductions, energy access to an additional 6 million rural customers and reduction of carbon dioxide emissions by 10.6 million tonnes in 2030. The Roadmap also finds that 91% of this technical potential is cost-effective, and 47% is achievable under conservative assumptions. The Roadmap prioritizes recommendations for implementing energy efficiency and maximizing benefits to meet the goals and priorities established in Uganda’s 2015 SEforALL Action Agenda. One important step is to create and increase demand for efficiency through long-term enabling policies and financial incentives

Energy efficiency criteria in uninterruptible power supply selection

International Nuclear Information System (INIS)

Moreno-Munoz, A.; Rosa, Juan Jose Gonzalez de la; Flores-Arias, J.M.; Bellido-Outerino, F.J.; Gil-de-Castro, A.

2011-01-01

With the generalized use of microelectronic devices, server computers and other susceptible equipment, the subject related to power quality (PQ) and its relationship to vulnerability of high performance plants are becoming an increasing concern to the industry. This paper addresses how uninterruptible power supply (UPS), particularly when configured in distributed DC mode, can become an energy efficient (EE) solution in high-tech buildings, especially when integrated with complimentary PQ measures. The paper is based on PQ audits conducted at different high-tech industries over the last years. It was found that the main problems for the equipment installed were voltage sags (or dips). Among all categories of electrical disturbances, voltage sags and momentary interruptions are the nemeses of the automated industrial process. The paper analyzes the capabilities of modern electronic power supplies and the convenience of embedded solution. Finally it is addresses the role of the Standards on the protection of electronic equipment and the implications for the final costumer.

Energy-Efficient Power Allocation of Cognitive Radio Systems without CSI at the Transmitter

KAUST Repository

Sboui, Lokman

2015-01-07

Two major issues are facing today’s wireless communications evolution: -Spectrum scarcity: Need for more bandwidth. As a solution, the Cognitive Radio (CR) paradigm, where secondary users (unlicensed) share the spectrum with licensed users, was introduced. -Energy consumption and CO2 emission: The ICT produce 2% of global CO2 emission (equivalent to the aviation industry emission). The cellular networks produces 0.2%. As solution energy efficient systems should be designed rather than traditional spectral efficient systems. In this work, we aim to determine the optimal energy efficient power allocation of CR when the channel state information at the transmitter CSI-T is not available.

Energy-Efficient Power Allocation of Cognitive Radio Systems without CSI at the Transmitter

KAUST Repository

Sboui, Lokman; Rezki, Zouheir; Alouini, Mohamed-Slim

2015-01-01

Two major issues are facing today’s wireless communications evolution: -Spectrum scarcity: Need for more bandwidth. As a solution, the Cognitive Radio (CR) paradigm, where secondary users (unlicensed) share the spectrum with licensed users, was introduced. -Energy consumption and CO2 emission: The ICT produce 2% of global CO2 emission (equivalent to the aviation industry emission). The cellular networks produces 0.2%. As solution energy efficient systems should be designed rather than traditional spectral efficient systems. In this work, we aim to determine the optimal energy efficient power allocation of CR when the channel state information at the transmitter CSI-T is not available.

Energy Efficient Monitoring for Intrusion Detection in Battery-Powered Wireless Mesh Networks

KAUST Repository

Hassanzadeh, Amin

2011-07-18

Wireless Mesh Networks (WMN) are easy-to-deploy, low cost solutions for providing networking and internet services in environments with no network infrastructure, e.g., disaster areas and battlefields. Since electric power is not readily available in such environments battery-powered mesh routers, operating in an energy efficient manner, are required. To the best of our knowledge, the impact of energy efficient solutions, e.g., involving duty-cycling, on WMN intrusion detection systems, which require continuous monitoring, remains an open research problem. In this paper we propose that carefully chosen monitoring mesh nodes ensure continuous and complete detection coverage, while allowing non-monitoring mesh nodes to save energy through duty-cycling. We formulate the monitoring node selection problem as an optimization problem and propose distributed and centralized solutions for it, with different tradeoffs. Through extensive simulations and a proof-of-concept hardware/software implementation we demonstrate that our solutions extend the WMN lifetime by 8%, while ensuring, at the minimum, a 97% intrusion detection rate.

Energy efficiency in pumps

International Nuclear Information System (INIS)

Kaya, Durmus; Yagmur, E. Alptekin; Yigit, K. Suleyman; Kilic, Fatma Canka; Eren, A. Salih; Celik, Cenk

2008-01-01

In this paper, 'energy efficiency' studies, done in a big industrial facility's pumps, are reported. For this purpose; the flow rate, pressure and temperature have been measured for each pump in different operating conditions and at maximum load. In addition, the electrical power drawn by the electric motor has been measured. The efficiencies of the existing pumps and electric motor have been calculated by using the measured data. Potential energy saving opportunities have been studied by taking into account the results of the calculations for each pump and electric motor. As a conclusion, improvements should be made each system. The required investment costs for these improvements have been determined, and simple payback periods have been calculated. The main energy saving opportunities result from: replacements of the existing low efficiency pumps, maintenance of the pumps whose efficiencies start to decline at certain range, replacements of high power electric motors with electric motors that have suitable power, usage of high efficiency electric motors and elimination of cavitation problems

Audio power amplifier techniques with energy efficient power conversion. Vol. 1

Energy Technology Data Exchange (ETDEWEB)

Nielsen, Karsten

1998-04-01

A fundamental study of both analog and digital pulse modulation methods is carried out. A novel class of multi-level pulse modulation methods - Phase Shifted Carrier Pulse Width Modulation (PSCPWM) - is introduced and show to have several advantageous features, primarily caused by the much improved synthesis of the modulating signal. Enhanced digital pulse modulation methods for digital Pulse Modulation Amplifier (PMA) systems are investigated, and a simple methodology for digital PWM modulator synthesis is devised. It is concluded, that the modulator performance is not a limitation in the system, regardless of the domain of modulator implementation. Power conversion in PMA systems is adressed from the perspective of both linearity and efficienty optimization. Based on detailed studies of the distortion mechanisms in the power conversion stage it is concluded, that this is the fundamental limitation on system performance due to several physical limitations. The analysis of general power stage efficiency concludes that dramatic improvements in energy efficiency are possible with PMA systems that are optimized for efficiency. A control system design methodology is devised as a platform for synthesis of robust control systems. Investigations of three fundamental control structures show that even simple control systems offer a remarkable value, although the considered topologies also have their limitations which is verified by practical evaluation in hardware. A novel control method is introduced - Multivariable Enhanced Cascade Control (MECC). MECC provides flexible control over all essential system parameters and is furthermore simple in realization. Practical evaluation of a MECC based PMA shows state-of-the-art performance. The application of non-linear control methods is investigated with the introduction of an enhanced non-linear control/modulator topology. Although the non-linear controller is theoretically interesting, the method proves to suffer from various

On energy efficient power allocation for power-constrained systems

KAUST Repository

Sboui, Lokman; Rezki, Zouheir; Alouini, Mohamed-Slim

2014-01-01

of the optimal power with instantaneous channel gain based on EE criterion. We show that the relation between the EE and the spectral efficiency (SE) when the optimal power is adopted is strictly increasing in contrast with the SE-EE trade-off discussed

Highly efficient solutions for smart and bulk power transmission of 'green energy'

Energy Technology Data Exchange (ETDEWEB)

Breuer, Wilfried; Retzmann, Dietmar; Uecker, Karl

2010-09-15

Environmental constraints, loss minimization and CO2 reduction will play an increasingly more important role in future. Security and sustainability of power supply as well as economic efficiency needs application of advanced technologies. Innovative solutions with HVDC (High Voltage Direct Current) and FACTS (Flexible AC Transmission Systems) have the potential to cope with these challenges. They provide the features which are necessary to avoid technical problems in power systems, they increase the transmission capacity and system stability very efficiently and help prevent cascading outages. Furthermore, they are essential for Grid Access of Renewable Energy Sources such as Hydro, Wind and Solar-Energy.

Does environmental regulation affect energy efficiency in China's thermal power generation? Empirical evidence from a slacks-based DEA model

International Nuclear Information System (INIS)

Bi, Gong-Bing; Song, Wen; Zhou, P.; Liang, Liang

2014-01-01

Data envelopment analysis (DEA) has gained much popularity in performance measurement of power industry. This paper presents a slack-based measure approach to investigating the relationship between fossil fuel consumption and the environmental regulation of China's thermal power generation. We first calculate the total-factor energy efficiency without considering environmental constraints. An environmental performance indicator is proposed through decomposing the total-factor energy efficiency. The proposed approach is then employed to examine whether environmental regulation affects the energy efficiency of China's thermal power generation. We find that the environmental efficiency plays a significant role in affecting energy performance of China's thermal generation sector. Decreasing the discharge of major pollutants can improve both energy performance and environmental efficiency. Besides, we also have three main findings: (1) The energy efficiency and environmental efficiency were relatively low. (2) The energy and environmental efficiency scores show great variations among provinces. (3) Both energy efficiency and environmental efficiency are of obvious geographical characteristics. According to our findings, we suggest some policy implications. - Highlights: • We assess the energy efficiency and the environmental efficiency of China's thermal power generation simultaneously. • The energy efficiency and the environmental efficiency were relatively low during 2007–2009. • The energy efficiency and environmental efficiency show obvious geographic characters. • The environmental performance of a DMU plays a decisive role in the energy performance

Energy efficiency of multiport power converters used in plug-in/V2G fuel cell vehicles

International Nuclear Information System (INIS)

Bizon, Nicu

2012-01-01

Highlights: ► It is proposed a new FC hybrid power source topology for plug-in FC vehicle (PFCV). ► An energy efficiency analysis of three architectures for Multiport Power Converter (MPC) of HPS is performed. ► The MPC energy efficiency features were shown by analytical computing in all PFCV regimes. -- Abstract: In this paper is presented an analysis of energy efficiency for the Multiport Power Converters (MPCs) used in Plug-in Fuel Cell Vehicles (PFCVs). A generic MPC architecture for PFCVs is proposed, which is analyzed for different operating modes of MPC in relation with PFCV operating regimes and the plug-in feature. The basic MPC architecture is described in relation with the PFCV operating regimes. Two MPC architectures are derived from the basic MPC architecture: (1) the MPC1 architecture, which is the MPC architecture without reverse power flow during regenerative braking process, and (2) the MPC2 architecture – MPC architecture without charging mode of Energy Storage System (ESS) from the FC system. Taking in account the imposed window for the ESS state-of-charge, the MPC can be connected to Plug-in Charging Stations (PCS) to exchange power with the Electric Power (EP) system, which will include renewable Distributed Generation (DG) systems. The Energy Management Unit (EMU) of MPC can communicate with the EP system to determine the moments that match the energy demand of plug-in vehicle with the supply availability of the EP system, stabilizing the EP system. The MPC features regarding its energy efficiency were shown by analytical computing performed and appropriate simulations presented in relation with the ESS that can be charged (discharged) from (to) the home/DG/EP system.

High-Efficiency Food Production in a Renewable Energy Based Micro-Grid Power System

Science.gov (United States)

Bubenheim, David; Meiners, Dennis

2016-01-01

Controlled Environment Agriculture (CEA) systems can be used to produce high-quality, desirable food year round, and the fresh produce can positively contribute to the health and well being of residents in communities with difficult supply logistics. While CEA has many positive outcomes for a remote community, the associated high electric demands have prohibited widespread implementation in what is typically already a fully subscribed power generation and distribution system. Recent advances in CEA technologies as well as renewable power generation, storage, and micro-grid management are increasing system efficiency and expanding the possibilities for enhancing community supporting infrastructure without increasing demands for outside supplied fuels. We will present examples of how new lighting, nutrient delivery, and energy management and control systems can enable significant increases in food production efficiency while maintaining high yields in CEA. Examples from Alaskan communities where initial incorporation of renewable power generation, energy storage and grid management techniques have already reduced diesel fuel consumption for electric generation by more than 40% and expanded grid capacity will be presented. We will discuss how renewable power generation, efficient grid management to extract maximum community service per kW, and novel energy storage approaches can expand the food production, water supply, waste treatment, sanitation and other community support services without traditional increases of consumable fuels supplied from outside the community. These capabilities offer communities with a range of choices to enhance their communities. The examples represent a synergy of technology advancement efforts to develop sustainable community support systems for future space-based human habitats and practical implementation of infrastructure components to increase efficiency and enhance health and well being in remote communities today and tomorrow.

Energy-Efficient Power Allocation for Fixed-Gain Amplify-and-Forward Relay Networks with Partial Channel State Information

KAUST Repository

Zafar, Ammar

2012-06-01

In this report, energy-efficient transmission and power allocation for fixed-gain amplify-and-forward relay networks with partial channel state information (CSI) are studied. In the energy-efficiency problem, the total power consumed is minimized while keeping the signal-to-noise-ratio (SNR) above a certain threshold. In the dual problem of power allocation, the end-to-end SNR is maximized under individual and global power constraints. Closed-form expressions for the optimal source and relay powers and the Lagrangian multiplier are obtained. Numerical results show that the optimal power allocation with partial CSI provides comparable performance as optimal power allocation with full CSI at low SNR.

Energy-Efficient Power Allocation for Fixed-Gain Amplify-and-Forward Relay Networks with Partial Channel State Information

KAUST Repository

Zafar, Ammar

2012-09-16

In this letter, energy-efficient transmission and power allocation for fixed-gain amplify-and-forward relay networks with partial channel state information (CSI) are studied. In the energy-efficiency problem, the total power consumed is minimized while keeping the signal-to-noise-ratio (SNR) above a certain threshold. In the dual problem of power allocation, the end-to-end SNR is maximized under individual and global power constraints. Closed-form expressions for the optimal source and relay powers and the Lagrangian multiplier are obtained. Numerical results show that the optimal power allocation with partial CSI provides comparable performance as optimal power allocation with full CSI at low SNR. © 2012 IEEE.

Energy efficiency of uninterruptible power supply systems (UPS); Projekt Energieeffizienz von USV-Anlagen

Energy Technology Data Exchange (ETDEWEB)

Schnyder, G.; Mauchle, P.

2005-03-15

This comprehensive final report for the Swiss Federal Office of Energy (SFOE) summarises and presents nine individual reports and documents concerning the topic of uninterruptible power supplies. The documents compiled for the Swiss Federal Office of Energy in earlier projects concerning the quality and energy efficiency of uninterruptible power supply (UPS) systems dating from 1998 to 2000 have been revised and expanded in collaboration with a UPS Systems 'Trendwatch' group. The central documents such as 'Optimised use of UPS systems', 'Measurement procedures for UPS systems', 'Label for UPS systems' and 'Quality/Energy matrix' have been translated into English. These documents form the basis for the international distribution of the studies and findings relating to the quality and energy efficiency of UPS systems. These results are to be distributed by both European as well as American commissions. A label and codes of conduct are being developed. The nine individual reports are summarised in separate abstracts also recorded in the ETDEWEB database.

Energy efficiency in pumps

Energy Technology Data Exchange (ETDEWEB)

Kaya, Durmus; Yagmur, E. Alptekin [TUBITAK-MRC, P.O. Box 21, 41470 Gebze, Kocaeli (Turkey); Yigit, K. Suleyman; Eren, A. Salih; Celik, Cenk [Engineering Faculty, Kocaeli University, Kocaeli (Turkey); Kilic, Fatma Canka [Department of Air Conditioning and Refrigeration, Kocaeli University, Kullar, Kocaeli (Turkey)

2008-06-15

In this paper, ''energy efficiency'' studies, done in a big industrial facility's pumps, are reported. For this purpose; the flow rate, pressure and temperature have been measured for each pump in different operating conditions and at maximum load. In addition, the electrical power drawn by the electric motor has been measured. The efficiencies of the existing pumps and electric motor have been calculated by using the measured data. Potential energy saving opportunities have been studied by taking into account the results of the calculations for each pump and electric motor. As a conclusion, improvements should be made each system. The required investment costs for these improvements have been determined, and simple payback periods have been calculated. The main energy saving opportunities result from: replacements of the existing low efficiency pumps, maintenance of the pumps whose efficiencies start to decline at certain range, replacements of high power electric motors with electric motors that have suitable power, usage of high efficiency electric motors and elimination of cavitation problems. (author)

77 FR 50489 - Office of Energy Efficiency and Renewable Energy

Science.gov (United States)

2012-08-21

... DEPARTMENT OF ENERGY Office of Energy Efficiency and Renewable Energy Wind and Water Power Program AGENCY: Office of Energy Efficiency and Renewable Energy, Department of Energy. ACTION: Notice of public... FURTHER INFORMATION CONTACT: Mr. Hoyt Battey, Office of Energy Efficiency and Renewable Energy, U.S...

The plant efficiency of fusion power stations

International Nuclear Information System (INIS)

Darvas, J.; Foerster, S.

1976-01-01

Due to the circulating energy, lower efficiencies are to be expected with fusion power plants than with nuclear fission power plants. According to the systems analysis, the mirror machine is not very promising as a power plant. The plant efficiency of the laser fusion strongly depends on the laser efficiency about which one can only make speculative statements at present. The Tokamak requires a relatively low circulating energy and is certainly able to compete regarding efficiency as long as the consumption time can be kept large (> 100 sec) and the dead time between the power pulses small ( [de

CMOS circuits for piezoelectric energy harvesters efficient power extraction, interface modeling and loss analysis

CERN Document Server

Hehn, Thorsten

2014-01-01

This book deals with the challenge of exploiting ambient vibrational energy which can be used to power small and low-power electronic devices, e.g. wireless sensor nodes. Generally, particularly for low voltage amplitudes, low-loss rectification is required to achieve high conversion efficiency. In the special case of piezoelectric energy harvesting, pulsed charge extraction has the potential to extract more power compared to a single rectifier. For this purpose, a fully autonomous CMOS integrated interface circuit for piezoelectric generators which fulfills these requirements is presented.Due

Simulation Modeling of Intelligent Control Algorithms for Constructing Autonomous Power Supply Systems with Improved Energy Efficiency

Directory of Open Access Journals (Sweden)

Gimazov Ruslan

2018-01-01

Full Text Available The paper considers the issue of supplying autonomous robots by solar batteries. Low efficiency of modern solar batteries is a critical issue for the whole industry of renewable energy. The urgency of solving the problem of improved energy efficiency of solar batteries for supplying the robotic system is linked with the task of maximizing autonomous operation time. Several methods to improve the energy efficiency of solar batteries exist. The use of MPPT charge controller is one these methods. MPPT technology allows increasing the power generated by the solar battery by 15 – 30%. The most common MPPT algorithm is the perturbation and observation algorithm. This algorithm has several disadvantages, such as power fluctuation and the fixed time of the maximum power point tracking. These problems can be solved by using a sufficiently accurate predictive and adaptive algorithm. In order to improve the efficiency of solar batteries, autonomous power supply system was developed, which included an intelligent MPPT charge controller with the fuzzy logic-based perturbation and observation algorithm. To study the implementation of the fuzzy logic apparatus in the MPPT algorithm, in Matlab/Simulink environment, we developed a simulation model of the system, including solar battery, MPPT controller, accumulator and load. Results of the simulation modeling established that the use of MPPT technology had increased energy production by 23%; introduction of the fuzzy logic algorithm to MPPT controller had greatly increased the speed of the maximum power point tracking and neutralized the voltage fluctuations, which in turn reduced the power underproduction by 2%.

Power Flow Distribution Strategy for Improved Power Electronics Energy Efficiency in Battery Storage Systems: Development and Implementation in a Utility-Scale System

Directory of Open Access Journals (Sweden)

Michael Schimpe

2018-03-01

Full Text Available Utility-scale battery storage systems typically consist of multiple smaller units contributing to the overall power dispatch of the system. Herein, the power distribution among these units is analyzed and optimized to operate the system with increased energy efficiency. To improve the real-life storage operation, a holistic system model for battery storage systems has been developed that enables a calculation of the energy efficiency. A utility-scale Second-Life battery storage system with a capacity of 3.3 MWh/3 MW is operated and evaluated in this work. The system is in operation for the provision of primary control reserve in combination with intraday trading for controlling the battery state of charge. The simulation model is parameterized with the system data. Results show that losses in power electronics dominate. An operational strategy improving the energy efficiency through an optimized power flow distribution within the storage system is developed. The power flow distribution strategy is based on the reduction of the power electronics losses at no-load/partial-load by minimizing their in-operation time. The simulation derived power flow distribution strategy is implemented in the real-life storage system. Field-test measurements and analysis prove the functionality of the power flow distribution strategy and reveal the reduction of the energy throughput of the units by 7%, as well as a significant reduction of energy losses in the units by 24%. The cost savings for electricity over the system’s lifetime are approximated to 4.4% of its investment cost.

Energy planning and energy efficiency assistance

Energy Technology Data Exchange (ETDEWEB)

Markel, L. [Electrotek Concepts, Inc., Knoxville, TN (United States)

1995-12-31

Electrotek is an engineering services company specializing in energy-related programs. Clients are most utilities, large energy users, and the U.S. Electric Power Research Institute. Electrotek has directed energy projects for the U.S. Agency for International Development and the U.S. Department of Energy in Poland and other countries of Central Europe. The objective is to assist the host country organizations to identify and implement appropriate energy efficiency and pollution reduction technologies, to transfer technical and organizational knowledge, so that further implementations are market-driven, without needed continuing foreign investment. Electrotek has worked with the Silesian Power Distribution Company to design an energy efficiency program for industrial customers that has proven to be profitable for the company and for its customers. The program has both saved energy and costs, and reduced pollution. The program is expanding to include additional customers, without needing more funding from the U.S. government.

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.

Energy Efficient Power Allocation in Multi-tier 5G Networks Using Enhanced Online Learning

KAUST Repository

Alqerm, Ismail

2017-07-25

The multi-tier heterogeneous structure of 5G with dense small cells deployment, relays, and device-to-device (D2D) communications operating in an underlay fashion is envisioned as a potential solution to satisfy the future demand for cellular services. However, efficient power allocation among dense secondary transmitters that maintains quality of service (QoS) for macro (primary) cell users and secondary cell users is a critical challenge for operating such radio. In this paper, we focus on the power allocation problem in the multi-tier 5G network structure using a non-cooperative methodology with energy efficiency consideration. Therefore, we propose a distributive intuition-based online learning scheme for power allocation in the downlink of the 5G systems, where each transmitter surmises other transmitters power allocation strategies without information exchange. The proposed learning model exploits a brief state representation to account for the problem of dimensionality in online learning and expedite the convergence. The convergence of the proposed scheme is proved and numerical results demonstrate its capability to achieve fast convergence with QoS guarantee and significant improvement in system energy efficiency.

Energy from the Earth's core. Using geothermal power efficiently; Heisse Energiequellen. Erdwaerme effizient nutzen

Energy Technology Data Exchange (ETDEWEB)

Anon.

2013-09-01

The heat stored and flowing beneath the surface of the Earth is an endless source of natural energy. It powers volcanoes, hot springs and geysers - and could supply the world with warmth and power. Linde engineers are using innovative technologies to help capture this geothermal energy efficiently. (orig.)

Model based design of efficient power take-off systems for wave energy converters

DEFF Research Database (Denmark)

Hansen, Rico Hjerm; Andersen, Torben Ole; Pedersen, Henrik C.

2011-01-01

The Power Take-Off (PTO) is the core of a Wave Energy Converter (WECs), being the technology converting wave induced oscillations from mechanical energy to electricity. The induced oscillations are characterized by being slow with varying frequency and amplitude. Resultantly, fluid power is often...... an essential part of the PTO, being the only technology having the required force densities. The focus of this paper is to show the achievable efficiency of a PTO system based on a conventional hydro-static transmission topology. The design is performed using a model based approach. Generic component models...

Energy Efficiency in Future PONs

DEFF Research Database (Denmark)

Reschat, Halfdan; Laustsen, Johannes Russell; Wessing, Henrik

2012-01-01

There is a still increasing tendency to give energy efficiency a high priority, even in already low energy demanding systems. This is also the case for Passive Optical Networks (PONs) for which many different methods for saving energy are proposed. This paper uses simulations to evaluate three...... proposed power saving solutions for PONs which use sleep mechanisms for saving power. The discovered advantages and disadvantages of these methods are then used as a basis for proposing a new solution combining different techniques in order to increase the energy efficiency further. This novel solution...

Energy-efficient relay selection and optimal power allocation for performance-constrained dual-hop variable-gain AF relaying

KAUST Repository

Zafar, Ammar

2013-12-01

This paper investigates the energy-efficiency enhancement of a variable-gain dual-hop amplify-and-forward (AF) relay network utilizing selective relaying. The objective is to minimize the total consumed power while keeping the end-to-end signal-to-noise-ratio (SNR) above a certain peak value and satisfying the peak power constraints at the source and relay nodes. To achieve this objective, an optimal relay selection and power allocation strategy is derived by solving the power minimization problem. Numerical results show that the derived optimal strategy enhances the energy-efficiency as compared to a benchmark scheme in which both the source and the selected relay transmit at peak power. © 2013 IEEE.

The effect of size-control policy on unified energy and carbon efficiency for Chinese fossil fuel power plants

International Nuclear Information System (INIS)

Zhang, Ning; Kong, Fanbin; Choi, Yongrok; Zhou, P.

2014-01-01

This paper examines the effect of size control policy on the energy and carbon efficiency for Chinese fossil fuel power industry. For this purpose, we propose two non-radial directional distance functions for energy/carbon efficiency analysis of fossil fuel electricity generation. One is named a total-factor directional distance function that incorporates the inefficiency of all input and output factors to measure the unified (operational and environmental) efficiency of fossil fuel power plants, and the other is called an energy–environmental directional distance function that can be used to measure the energy–environmental performance of fossil fuel electric power plants. Several standardized indicators for measuring unified efficiency and energy–environmental performance are derived from the two directional distance functions. An empirical study of 252 fossil fuel power plants in China is conducted by using the proposed approach. Our empirical results show that there exists a significant positive relationship between the plant size and unified efficiency, the five state-owned companies show lower unified efficiency and energy–environmental performance than other companies. It is suggested that Chinese government might need to consider private incentives and deregulation for its state-owned enterprises to improve their performance proactively. - Highlights: • Two non-radial directional distance functions are presented for energy/carbon efficiency analysis. • An empirical study of 252 fossil fuel power plants in China is conducted. • The five state-owned companies show lower unified efficiency and energy–environmental performance

A thermally regenerative ammonia-based battery for efficient harvesting of low-grade thermal energy as electrical power

KAUST Repository

Zhang, Fang

2015-01-01

© 2015 The Royal Society of Chemistry. Thermal energy was shown to be efficiently converted into electrical power in a thermally regenerative ammonia-based battery (TRAB) using copper-based redox couples [Cu(NH3)4 2+/Cu and Cu(ii)/Cu]. Ammonia addition to the anolyte (2 M ammonia in a copper-nitrate electrolyte) of a single TRAB cell produced a maximum power density of 115 ± 1 W m-2 (based on projected area of a single copper mesh electrode), with an energy density of 453 W h m-3 (normalized to the total electrolyte volume, under maximum power production conditions). Adding a second cell doubled both the voltage and maximum power. Increasing the anolyte ammonia concentration to 3 M further improved the maximum power density to 136 ± 3 W m-2. Volatilization of ammonia from the spent anolyte by heating (simulating distillation), and re-addition of this ammonia to the spent catholyte chamber with subsequent operation of this chamber as the anode (to regenerate copper on the other electrode), produced a maximum power density of 60 ± 3 W m-2, with an average discharge energy efficiency of ∼29% (electrical energy captured versus chemical energy in the starting solutions). Power was restored to 126 ± 5 W m-2 through acid addition to the regenerated catholyte to decrease pH and dissolve Cu(OH)2 precipitates, suggesting that an inexpensive acid or a waste acid could be used to improve performance. These results demonstrated that TRABs using ammonia-based electrolytes and inexpensive copper electrodes can provide a practical method for efficient conversion of low-grade thermal energy into electricity.

Energy efficiency comparison between geothermal power systems

Directory of Open Access Journals (Sweden)

Luo Chao

2017-01-01

Full Text Available The geothermal water which can be considered for generating electricity with the temperature ranging from 80℃ to 150℃ in China because of shortage of electricity and fossil energy. There are four basic types of geothermal power systems: single flash, double flash, binary cycle, and flash-binary system, which can be adapted to geothermal energy utilization in China. The paper discussed the performance indices and applicable conditions of different power system. Based on physical and mathematical models, simulation result shows that, when geofluid temperature ranges from 100℃ to 130℃, the net power output of double flash power is bigger than flash-binary system. When the geothermal resource temperature is between 130℃ and 150℃, the net power output of flash-binary geothermal power system is higher than double flash system by the maximum value 5.5%. However, the sum water steam amount of double flash power system is 2 to 3 times larger than flash-binary power system, which will cause the bigger volume of equipment of power system. Based on the economy and power capacity, it is better to use flash-binary power system when the geofluid temperature is between 100℃ and 150℃.

Energy efficiency, renewable energy and sustainable development

Energy Technology Data Exchange (ETDEWEB)

Ervin, C.A.

1994-12-31

The Office of Energy Efficiency and Renewable Energy (EE) is part of the U.S. Department of Energy that is specifically charged with encouraging the more efficient use of energy resources, and the use of renewable energy resources - such as solar power, wind power, biomass energy and geothermal energy. In the past several years, EE has increased its emphasis on technology deployment through partnerships with states, local governments and private companies. Partnerships move new discoveries more quickly into the marketplace, where they can create jobs, prevent pollution, save resources, and produce many other benefits. The author then emphasizes the importance of this effort in a number of different sections of the paper: energy consumption pervades everything we do; U.S. energy imports are rising to record levels; transportation energy demand is increasing; U.S. energy use is increasing; population growth increases world energy demand; total costs of energy consumption aren`t always counted; world energy markets offer incredible potential; cost of renewables is decreasing; clean energy is essential to sustainable development; sustainable energy policy; sustainable energy initiatives: utilities, buildings, and transportation.

Energy efficiency, renewable energy and sustainable development

International Nuclear Information System (INIS)

Ervin, C.A.

1994-01-01

The Office of Energy Efficiency and Renewable Energy (EE) is part of the U.S. Department of Energy that is specifically charged with encouraging the more efficient use of energy resources, and the use of renewable energy resources - such as solar power, wind power, biomass energy and geothermal energy. In the past several years, EE has increased its emphasis on technology deployment through partnerships with states, local governments and private companies. Partnerships move new discoveries more quickly into the marketplace, where they can create jobs, prevent pollution, save resources, and produce many other benefits. The author then emphasizes the importance of this effort in a number of different sections of the paper: energy consumption pervades everything we do; U.S. energy imports are rising to record levels; transportation energy demand is increasing; U.S. energy use is increasing; population growth increases world energy demand; total costs of energy consumption aren't always counted; world energy markets offer incredible potential; cost of renewables is decreasing; clean energy is essential to sustainable development; sustainable energy policy; sustainable energy initiatives: utilities, buildings, and transportation

Highly efficient power system based on direct fission fragment energy conversion utilizing magnetic collimation

International Nuclear Information System (INIS)

Tsvetkov, Pavel V.; Hart, Ron R.; Parish, Theodore A.

2003-01-01

The present study was focused on developing a technologically feasible power system that is based on direct fission fragment energy conversion utilizing magnetic collimation. The new concept is an attempt to combine several advantageous design solutions, which have been proposed for application in both fission and fusion reactors, into one innovative system that can offer exceptional energy conversion efficiency. The analysis takes into consideration a wide range of operational aspects including fission fragment escape from the fuel, collimation, collection, criticality, long-term performance, energy conversion efficiency, heat removal, and safety characteristics. Specific characteristics of the individual system components and the entire system are evaluated. Consistent analysis and evaluation of the technological feasibility of the concept were achieved using state-of-the-art computer codes that allowed realistic and consistent modeling. The calculated energy conversion efficiencies for the presented designs without a thermodynamic cycle and with the heavy water cycle are 52% and 62%, respectively. The analysis indicates that efficiencies up to 90% are potentially achievable. (author)

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.)

Energy efficiency for the multiport power converters architectures of series and parallel hybrid power source type used in plug-in/V2G fuel cell vehicles

International Nuclear Information System (INIS)

Bizon, Nicu

2013-01-01

Highlights: ► It is analyzed the series and parallel Hybrid Power Source (HPS) topology for plug-in Fuel Cell Vehicle (PFCV). ► An energy efficiency analysis of the Multiport Power Converter (MPC) of both HPSs is performed. ► The MPC energy efficiency features were shown by analytical computing in all PFCV regimes. -- Abstract: In this paper it is presented a mathematical analysis of the energy efficiency for the Multiport Power Converter (MPC) used in series and parallel Hybrid Power Source (HPS) architectures type on the plug-in Fuel Cell Vehicles (PFCVs). The aim of the analysis is to provide general conclusions for a wide range of PFCV operating regimes that are chosen for efficient use of the MPC architecture on each particular drive cycle. In relation with FC system of PFCV, the Energy Storage System (ESS) can operate in following regimes: (1) Charge-Sustaining (CS), (2) Charge-Depleting (CD), and (3) Charge-Increasing (CI). Considering the imposed window for the ESS State-Of-Charge (SOC), the MPC can be connected to renewable plug-in Charging Stations (PCSs) to exchange power with Electric Power (EP) system, when it is necessary for both. The Energy Management Unit (EMU) that communicates with the EP system will establish the moments to match the PFCV power demand with supply availability of the EP grid, stabilizing it. The MPC energy efficiency of the PFCVs is studied when the ESS is charged (discharged) from (to) the home/PCS/EP system. The comparative results were shown for both PFCV architectures through the analytical calculation performed and the appropriate Matlab/Simulink® simulations presented.

On Energy-Efficient Hierarchical Cross-Layer Design: Joint Power Control and Routing for Ad Hoc Networks

Directory of Open Access Journals (Sweden)

Poor HVincent

2007-01-01

Full Text Available A hierarchical cross-layer design approach is proposed to increase energy efficiency in ad hoc networks through joint adaptation of nodes' transmitting powers and route selection. The design maintains the advantages of the classic OSI model, while accounting for the cross-coupling between layers, through information sharing. The proposed joint power control and routing algorithm is shown to increase significantly the overall energy efficiency of the network, at the expense of a moderate increase in complexity. Performance enhancement of the joint design using multiuser detection is also investigated, and it is shown that the use of multiuser detection can increase the capacity of the ad hoc network significantly for a given level of energy consumption.

On Energy-Efficient Hierarchical Cross-Layer Design: Joint Power Control and Routing for Ad Hoc Networks

Directory of Open Access Journals (Sweden)

Cristina Comaniciu

2007-03-01

Full Text Available A hierarchical cross-layer design approach is proposed to increase energy efficiency in ad hoc networks through joint adaptation of nodes' transmitting powers and route selection. The design maintains the advantages of the classic OSI model, while accounting for the cross-coupling between layers, through information sharing. The proposed joint power control and routing algorithm is shown to increase significantly the overall energy efficiency of the network, at the expense of a moderate increase in complexity. Performance enhancement of the joint design using multiuser detection is also investigated, and it is shown that the use of multiuser detection can increase the capacity of the ad hoc network significantly for a given level of energy consumption.

Using energy efficiently

International Nuclear Information System (INIS)

Nipkow, J.; Brunner, C. U.

2005-01-01

This comprehensive article discusses the perspectives for reducing electricity consumption in Switzerland. The increase in consumption is discussed that has occurred in spite of the efforts of the Swiss national energy programmes 'Energy 2000' and 'SwissEnergy'. The fact that energy consumption is still on the increase although efficient and economically-viable technology is available is commented on. The authors are of the opinion that the market alone cannot provide a complete solution and that national and international efforts are needed to remedy things. In particular, the external costs that are often not included when estimating costs are stressed. Several technical options available, such as the use of fluorescent lighting, LCD monitors and efficient electric motors, are looked at as are other technologies quoted as being a means of reducing power consumption. Ways of reducing stand-by losses and system optimisation are looked at as are various scenarios for further development and measures that can be implemented in order to reduce power consumption

Energy efficiency and renewables policies: Promoting efficiency or facilitating monopsony?

International Nuclear Information System (INIS)

Brennan, Timothy J.

2011-01-01

The cliche in the electricity sector, the 'cheapest power plant is the one we don't build,' neglects the benefits of the energy that plant would generate. That economy-wide perspective need not apply in considering benefits to only consumers if not building that plant was the exercise of monopsony power. A regulator maximizing consumer welfare may need to avoid rationing demand at monopsony prices. Subsidizing energy efficiency to reduce electricity demand at the margin can solve that problem, if energy efficiency and electricity use are substitutes. Renewable energy subsidies, percentage use standards, or feed in tariffs may also serve monopsony as well with sufficient inelasticity in fossil fuel electricity supply. We may not observe these effects if the regulator can set price as well as quantity, lacks buyer-side market power, or is legally precluded from denying generators a reasonable return on capital. Nevertheless, the possibility of monopsony remains significant in light of the debate as to whether antitrust enforcement should maximize consumer welfare or total welfare. - Research Highlights: → Subsidizing energy efficiency can promote monopsony, if efficiency and use are substitutes. → Renewable energy subsidies, portfolio standards, or feed-in tariffs may also promote monopsony. → Effects require buyer-side market power and ability to deny generators a reasonable return. → Monopsony is significant in light of whether antitrust should maximize consumer or total welfare.

Research for energy efficiency; Forschung fuer Energieeffizienz

Energy Technology Data Exchange (ETDEWEB)

NONE

2010-09-15

The Federal Ministry of Economy enhanced its funding for research in the field of non-nuclear energy in the programme ''Forschung fuer Energieeffizienz'' (Research for Energy Efficiency). The programme focuses on established areas like modern power plant technologies (''Moderne Kraftwerkstechnologien''), fuel cells and hydrogen (''Brennstoffzelle, Wasserstoff''), and energy-optimized building construction (''Energieoptimiertes Bauen''). New subjects are energy-efficient towns and cities (''Energieeffiziente Stadt''), power grids for future power supply (''Netze fuer die Stromversorgung der Zukunft''), power storage (''Stromspeicher''), and electromobility (''Elektromobilitaet''). The brochure presents research and demonstration projects that illustrate the situation in 2010 when the programme was initiated. (orig.)

Energy efficiency vs. performance of the numerical solution of PDEs: An application study on a low-power ARM-based cluster

Science.gov (United States)

Göddeke, Dominik; Komatitsch, Dimitri; Geveler, Markus; Ribbrock, Dirk; Rajovic, Nikola; Puzovic, Nikola; Ramirez, Alex

2013-03-01

Power consumption and energy efficiency are becoming critical aspects in the design and operation of large scale HPC facilities, and it is unanimously recognised that future exascale supercomputers will be strongly constrained by their power requirements. At current electricity costs, operating an HPC system over its lifetime can already be on par with the initial deployment cost. These power consumption constraints, and the benefits a more energy-efficient HPC platform may have on other societal areas, have motivated the HPC research community to investigate the use of energy-efficient technologies originally developed for the embedded and especially mobile markets. However, lower power does not always mean lower energy consumption, since execution time often also increases. In order to achieve competitive performance, applications then need to efficiently exploit a larger number of processors. In this article, we discuss how applications can efficiently exploit this new class of low-power architectures to achieve competitive performance. We evaluate if they can benefit from the increased energy efficiency that the architecture is supposed to achieve. The applications that we consider cover three different classes of numerical solution methods for partial differential equations, namely a low-order finite element multigrid solver for huge sparse linear systems of equations, a Lattice-Boltzmann code for fluid simulation, and a high-order spectral element method for acoustic or seismic wave propagation modelling. We evaluate weak and strong scalability on a cluster of 96 ARM Cortex-A9 dual-core processors and demonstrate that the ARM-based cluster can be more efficient in terms of energy to solution when executing the three applications compared to an x86-based reference machine.

Modus operandi for maximizing energy efficiency and increasing permeate flux of community scale solar powered reverse osmosis systems

International Nuclear Information System (INIS)

Vyas, Harsh; Suthar, Krunal; Chauhan, Mehul; Jani, Ruchita; Bapat, Pratap; Patel, Pankaj; Markam, Bhupendra; Maiti, Subarna

2015-01-01

Highlights: • Experimental data on energy efficient photovoltaic powered reverse osmosis system. • Synergetic management of electrical, thermal and hydraulic energies. • Use of reflectors, heat exchanger and turgo turbine. - Abstract: Photovoltaic powered reverse osmosis systems can only be made cost effective if they are made highly energy efficient. In this work we describe a protocol to maximize energy efficiency and increase permeate flux in a fully integrated installation of such a system. The improved system consisted of (i) photovoltaic array fitted with suitably positioned and aligned North–South V-trough reflectors to enhance power output from the array; (ii) direct contact heat exchanger fitted on the rear of the photovoltaic modules for active cooling of the same while safeguarding the terminals from short-circuit and corrosion; (iii) use of reverse osmosis feed water as heat exchange medium while taking due care to limit the temperature rise of feed water; (iv) enhancing permeate flux through the rise in feed water temperature; (v) turgo-turbine for conversion of hydraulic energy in reverse osmosis reject water into mechanical energy to provide part of the energy to replace booster pump utilized in the reverse osmosis unit. The V-trough reflectors onto the photovoltaic modules with thermal energy recovery system brought about an increase in power output of 40% and the synergistic effect of (i)–(iv) gave rise to total permeate volume boost of 59%. Integration of (v) resulted in 56% and 26% saving of electrical power when the reverse osmosis plant was operated by battery bank and direct photovoltaic array respectively

Multi-objective design and operation of Solid Oxide Fuel Cell (SOFC) Triple Combined-cycle Power Generation systems: Integrating energy efficiency and operational safety

International Nuclear Information System (INIS)

Sharifzadeh, Mahdi; Meghdari, Mojtaba; Rashtchian, Davood

2017-01-01

Highlights: • Integrating Solid Oxide Fuel Cells with thermal power plants enhance overall energy efficiency. • However, the high degree of process integration in hybrid power plants limits the operating window. • Multi-objective optimization was applied for integrated design and operation. • The Pareto optimal solutions demonstrated strong trade-off between energy efficiency and operational safety. - Abstract: Energy efficiency is one of the main pathways for energy security and environmental protection. In fact, the International Energy Agency asserts that without energy efficiency, 70% of targeted emission reductions are not achievable. Despite this clarity, enhancing the energy efficiency introduce significant challenge toward process operation. The reason is that the methods applied for energy-saving pose the process operation at the intersection of safety constraints. The present research aims at uncovering the trade-off between safe operation and energy efficiency; an optimization framework is developed that ensures process safety and simultaneously optimizes energy-efficiency, quantified in economic terms. The developed optimization framework is demonstrated for a solid oxide fuel cell (SOFC) power generation system. The significance of this industrial application is that SOFC power plants apply a highly degree of process integration resulting in very narrow operating windows. However, they are subject to significant uncertainties in power demand. The results demonstrate a strong trade-off between the competing objectives. It was observed that highly energy-efficient designs feature a very narrow operating window and limited flexibility. For instance, expanding the safe operating window by 100% will incur almost 47% more annualized costs. Establishing such a trade-off is essential for realizing energy-saving.

Moving around efficiently: Energy and transportation

Directory of Open Access Journals (Sweden)

Hermans L. J. F.

2013-06-01

Full Text Available Worldwide, transportation takes almost 20% of the total energy use, and more than half of the oil consumption. By far the largest part is used by cars powered by internal combustion engines. The reason is simple: oil and gasoline are ideal energy carriers for transportation, since their energy density is extremely high. However, in terms of energy efficiency the internal combustion engine has a poor performance: about 25% only. How does this compare with electric cars? What are the alternative transportation systems and their efficiencies anyway? In this lecture we will analyse the efficiency of various transport systems, using elementary physics principles. We will look at cars, buses, trains and TGVs, ships, aircraft and zeppelins. Also the efficiency of human powered vehicles will be considered. Special attention is given to future mobile energy carriers like hydrogen, batteries and super capacitors.

An Energy-Efficient Link with Adaptive Transmit Power Control for Long Range Networks

DEFF Research Database (Denmark)

Lynggaard, P.; Blaszczyk, Tomasz

2016-01-01

A considerable amount of research is carried out to develop a reliable smart sensor system with high energy efficiency for battery operated wireless IoT devices in the agriculture sector. However, only a limited amount of research has covered automatic transmission power adjustment schemes...... and algorithms which are essential for deployment of wireless IoT nodes. This paper presents an adaptive link algorithm for farm applications with emphasis on power adjustment for long range communication networks....

The role of the power/efficiency misconception in the rebound effect's size debate: Does efficiency actually lead to a power enhancement?

International Nuclear Information System (INIS)

Ruzzenenti, F.; Basosi, R.

2008-01-01

This paper addresses the question of whether the rebound effect's size is bigger or smaller than one. After a brief review of the related economic literature, a thermodynamic perspective tackles this topic by demonstrating that the dispute over the size of the rebound effect relies on a misconception of the thermodynamic nature of energy efficiency. The dichotomy, in fact, concerns the relationship between efficiency and power output rather than the scale of the economic side effects generated by energy efficiency mutations. Early intuitions of the dichotomy efficiency/power belong to the pioneering works of Stanley Jevons, in the field of economics, and Alfred Lotka in that of biology. Their findings are here approached using the basis of finite-time thermodynamics with a simple amendment, the addition of the time variable to the Carnot machinery. The model shows how a process of power maximization always leads to a sub-optimal efficiency level and additionally, that any efficiency improvement, in the context of low energy costs, will shift the power output of the machine instead of reducing energy consumption. A case study taken from the transport system is presented to elucidate this argument

Green corridor : energy efficiency initiatives

Energy Technology Data Exchange (ETDEWEB)

Bartlett, M.; Strickland, R.; Harding, N. [Windsor Univ., ON (Canada)

2005-07-01

This presentation discussed environmental sustainability using alternative energy technologies. It discussed Ecohouse, which is a house designed using conventional and inventive products and techniques to represent an eco-efficient model for living, a more sustainable house, demonstrating sustainable technologies in action and setting a new standard for resource efficiency in Windsor. The presentation provided a building analysis and discussed the following: geothermal heating; distributive power; green roof; net metering; grey water plumbing; solar water heating; passive lighting; energy efficient lighting and geothermal heating and cooling. It also discussed opportunities for innovation, namely: greenhouse; composting toilets; alternative insulation; net metering; solar arrays; hydroponics; and expansion of the house. Also discussed were a nature bridge, an underwater electric kite, and a vertically aerodynamic turbine. The benefits of renewable energy, small hydro power potential, and instream energy generation technology were presented. 9 refs., figs.

Profiling high performance dense linear algebra algorithms on multicore architectures for power and energy efficiency

KAUST Repository

Ltaief, Hatem

2011-08-31

This paper presents the power profile of two high performance dense linear algebra libraries i.e., LAPACK and PLASMA. The former is based on block algorithms that use the fork-join paradigm to achieve parallel performance. The latter uses fine-grained task parallelism that recasts the computation to operate on submatrices called tiles. In this way tile algorithms are formed. We show results from the power profiling of the most common routines, which permits us to clearly identify the different phases of the computations. This allows us to isolate the bottlenecks in terms of energy efficiency. Our results show that PLASMA surpasses LAPACK not only in terms of performance but also in terms of energy efficiency. © 2011 Springer-Verlag.

Power-Efficient Design Challenges

Science.gov (United States)

Pangrle, Barry

Design teams find themselves facing decreasing power budgets while simultaneously the products that they design continue to require the integration of increasingly complex levels of functionality. The market place (driven by consumer preferences) and new regulations and guidelines on energy efficiency and environmental impact are the key drivers. This in turn has generated new approaches in all IC and electronic system design domains from the architecture to the physical layout of ICs, to design-for-test, as well as for design verification to insure that the design implementation actually meets the intended requirements and specifications. This chapter covers key aspects of these forces from a technological and market perspective that are driving designers to produce more energy-efficient products. Observations by significant industry leaders from AMD, ARM, IBM, Intel, nVidia and TSMC are cited, and the emerging techniques and technologies used to address these issues now and into the future are explored. Topic areas include: System level: Architectural analysis and transaction-level modeling. How architectural decisions can dramatically reduce the design power and the importance of modeling hardware and software together. IC (Chip) level: The impact of creating on-chip power domains for selectively turning power off and/or multi-voltage operation on: (1) chip verification, (2) multi-corner multi-mode analysis during placement and routing of logic cells and (3) changes to design-for-test, all in order to accommodate for power-gating and multi-voltage control logic, retention registers, isolation cells and level shifters needed to implement these power saving techniques. Process level: The disappearing impact of body-bias techniques on leakage control and why new approaches like High-K Metal Gate (HKMG) technology help but don't eliminate power issues. Power-efficient design is impacting the way chip designers work today, and this chapter focuses on where the most

Electrical efficiency and renewable energy - Economical alternatives to large-scale power generation

International Nuclear Information System (INIS)

Oettli, B.; Hammer, S.; Moret, F.; Iten, R.; Nordmann, T.

2010-05-01

This final report for WWF Switzerland, Greenpeace Switzerland, the Swiss Energy Foundation SES, Pro Natura and the Swiss Cantons of Basel City and Geneva takes a look at the energy-relevant effects of the propositions made by Swiss electricity utilities for large-scale power generation. These proposals are compared with a strategy that proposes investments in energy-efficiency and the use of renewable sources of energy. The effects of both scenarios on the environment and the risks involved are discussed, as are the investments involved. The associated effects on the Swiss national economy are also discussed. For the efficiency and renewables scenario, two implementation variants are discussed: Inland investments and production are examined as are foreign production options and/or import from foreign countries. The methods used in the study are introduced and discussed. Investment and cost considerations, earnings and effects on employment are also reviewed. The report is completed with an extensive appendix which, amongst other things, includes potential reviews, cost estimates and a discussion on 'smart grids'

Certification and brand identity for energy efficiency in competitive energy services markets

Energy Technology Data Exchange (ETDEWEB)

Prindle, W.R.; Wiser, R.

1998-07-01

Resource commitments for energy efficiency from electricity companies are disappearing rapidly as the regulated Integrated Resource Planning and Demand-Side Management paradigms that fostered them give way to competitive power markets in a restructuring electricity industry. While free-market advocates claim that energy efficiency needs will be taken care of by competitive energy service providers, there is no assurance that efficiency will compete effectively with the panoply of other energy-related (and non-energy-related) services that are beginning to appear in early market offerings. This paper reports the results of a feasibility study for a certification and brand identity program for energy efficiency geared to competitive power markets. Funded by the Energy Foundation, this study involved a survey and personal interviews with stakeholders, plus a workshop to further the discussion. Stakeholders include independent power marketers and energy service companies, utility affiliate power marketers and energy service companies, government agencies, trade associations, non-profit organizations, equipment manufacturers, and consultants. The paper summarizes the study's findings on such key issues as: Whether a brand identity concept has a critical mass of interest and support; how qualification and certification could work in such a program; how a brand identity could be positioned in the market; how an efficiency brand identity could co-brand with renewable power branding programs and other green marketing efforts; and the resources and components needed to make such a program work on a national scale.

Design method of a power management strategy for variable battery capacities range-extended electric vehicles to improve energy efficiency and cost-effectiveness

International Nuclear Information System (INIS)

Du, Jiuyu; Chen, Jingfu; Song, Ziyou; Gao, Mingming; Ouyang, Minggao

2017-01-01

Energy management strategy and battery capacity are the primary factors for the energy efficiency of range-extended electric buses (REEBs). To improve the energy efficiency of REEBs developed by Tsinghua University, an optimal design method of global optimization-based strategy is investigated. It is real-time and adaptive to variable traction battery capacities of series REEBs. For simulation, the physical model of REEB and key components are established. The optimal strategy is first extracted by the power split ratio (PSR) from REEB simulation result with dynamic program (DP) algorithm. The power distribution map is obtained by series simulations for variable battery capacity options. The control law for developing optimal strategy are achieved by cluster regression for power distribution data. To verify the effect of the proposed energy management strategy, characteristics of powertrain, energy efficiency, operating cost, and computing time are ultimately analyzed. Simulation results show that the energy efficiency of the global optimization-based strategy presented in this paper is similar to that of the DP strategy. Therefore, the overall energy efficiency can be significantly improved compared with that of the CDCS strategy, and operating costs can be substantially reduced. The feasibility of candidate control strategies is thereby assessed via the employment of variable parameters. - Highlights: • Analysis method of powertrain energy efficiency and power distribution is proposed. • The power distribution rules of strategy with variable battery capacities are achieved. • The parametric method of proposed PSR-RB strategy is presented. • The energy efficiency of powertrain is analysis by flow analysis method. • The energy management strategy is global optimization-based and real-time.

Efficiency of Finish power transmission network companies

International Nuclear Information System (INIS)

Anon.

2001-01-01

The Finnish Energy Market Authority has investigated the efficiency of power transmissions network companies. The results show that the intensification potential of the branch is 402 million FIM, corresponding to about 15% of the total costs of the branch and 7.3 % of the turnout. Energy Market Authority supervises the reasonableness of the power transmission prices, and it will use the results of the research in supervision. The research was carried out by the Quantitative Methods Research Group of Helsinki School of Economics. The main objective of the research was to create an efficiency estimation method for electric power distribution network business used for Finnish conditions. Data of the year 1998 was used as basic material in the research. Twenty-one of the 102 power distribution network operators was estimated to be totally efficient. Highest possible efficiency rate was 100, and the average of the efficiency rates of all the operators was 76.9, the minimum being 42.6

The energy-efficiency business - Energy utility strategies

International Nuclear Information System (INIS)

Loebbe, S.

2009-01-01

This article takes a look at the energy-efficiency business and the advantages it offers. The author quotes that energy-efficiency can contribute to making savings in primary energy, minimise the economic impact of global warming, improve reliability of supply and protect the gross national product. The advantages of new products for the efficient use of energy are reviewed and the resulting advantages for power customers are noted. Also, possibilities for the positioning of electricity suppliers in the environmental niche is noted. The partial markets involved and estimates concerning the impact of energy-efficiency measures are reviewed. Climate protection, co-operation with energy agencies, consulting services and public relations aspects are also discussed. The prerequisites for successful marketing by the utilities are examined and new business models are discussed along with the clear strategies needed. The development from an electricity utility to a system-competence partner is reviewed

Environmental co-benefits of energy efficiency improvement in coal-fired power sector: A case study of Henan Province, China

International Nuclear Information System (INIS)

Wang, Ke; Wang, Shanshan; Liu, Lei; Yue, Hui; Zhang, Ruiqin; Tang, Xiaoyan

2016-01-01

Highlights: • Pollutant surcharge is considered in Energy Conservation Supply Curve. • Intake Fraction method is incorporated into Energy Conservation Supply Curve. • Health benefits contribute 97% of co-benefits of energy efficiency improvement. - Abstract: The coal-fired power sector is one of the major contributors to environmental problems and has great potential of air pollution abatement. This study employs Energy Conservation Supply Curves (ECSCs) combined with pollutant surcharge and health benefits to evaluate the environmental co-benefits of energy efficiency improvement in the coal-fired power sector. Health benefits and the pollution surcharge are considered as the environmental co-benefits that reduce costs of conserved energy (CCEs) in ECSCs. The health benefits of energy efficiency improvement are quantified using Intake Fraction method, while the pollutant surcharge is calculated based on the regulation. Three scenarios including a Business As Usual (BAU) scenario, an Energy Efficiency Improvement (EEI) scenario, and an Upgrading Standards and Incentive (USI) scenario is considered in a case study for Henan Province of China. Our results show that costs of conserved energy (CCEs) are reduced by 0.56 and 0.29 USD/GJ under the EEI and USI scenarios due to health benefits and pollutant surcharge reductions related to energy efficient technologies, respectively. In particular, health benefits account for 97% of the reductions in CCEs, while the pollutant surcharge only contributes 3%. Under the EEI and USI scenarios, in 2020, energy efficiency improvement reduces energy consumption in Henan’s coal-fired power sector by 3.3% and 3.5% compared with the BAU scenario, respectively. The EEI and USI scenarios indicates that health benefits of 1.5 × 10"9 and 2.4 × 10"9 USD are gained and the reductions of pollutant surcharges of 197 and 226 million USD are realized in 2020, respectively.

Energy technologies and energy efficiency in economic modelling

DEFF Research Database (Denmark)

Klinge Jacobsen, Henrik

1998-01-01

This paper discusses different approaches to incorporating energy technologies and technological development in energy-economic models. Technological development is a very important issue in long-term energy demand projections and in environmental analyses. Different assumptions on technological ...... of renewable energy and especially wind power will increase the rate of efficiency improvement. A technologically based model in this case indirectly makes the energy efficiency endogenous in the aggregate energy-economy model....... technological development. This paper examines the effect on aggregate energy efficiency of using technological models to describe a number of specific technologies and of incorporating these models in an economic model. Different effects from the technology representation are illustrated. Vintage effects...... illustrates the dependence of average efficiencies and productivity on capacity utilisation rates. In the long run regulation induced by environmental policies are also very important for the improvement of aggregate energy efficiency in the energy supply sector. A Danish policy to increase the share...

The effect of cojugate energy consumptions on comparative efficiency of alternatives of the development of nuclear power engineering

International Nuclear Information System (INIS)

Bubnov, V.P.; Bykov, A.I.; Egorushkin, S.V.

1987-01-01

The effect of control of conjugate energy consumptions on comparative efficiency of alternatives of the development of nuclear power engineering, including NPPs with thermal and fast reactors has been calculated. Economical-mathematical models of the system of nuclear power engineering including the subsystems of fuel utilization, fuel supply and conjugate industries, have been used. It has been shown, that with allowance for conjugate energy consumptions, the economic characteristics of nuclear power engineering sharply degradate when it develops only on the basis of thermal reactors. Putting the fast reactors into the system of nuclear power engineering has an important effect on reduction of conjugate energy consumptions and favors the increase of the efficiency of the system functioning during the considered time interval (60 years). Positive effects from putting breeders into operation become appreciable only on the latest estimated time intervals

Power sector reforms in Brazil and its impacts on energy efficiency and research and development activities

International Nuclear Information System (INIS)

Jannuzzi, G.M. de

2005-01-01

Since the mid-nineties Brazil has implemented significant changes in the country's power sector, including privatization, introduction of competition and the creation of regulatory agency. As reform started in Brazil traditional support to energy efficiency and energy research and development suffered a discontinuation, budget cuts and re-definition of roles of the public agents in charge. At the same time, new regulatory measures and the creation of a national public interest fund have helped to maintain and potentially enhance the country's effort to promote energy efficiency and investments in energy R and D. This paper analyses the impacts of these changes in the areas of energy efficiency and energy research and development and argues for an increased role of developing countries to provide solutions for a meeting energy demand requirements more suitable to their internal markets

Junction Temperature Aware Energy Efficient Router Design on FPGA

DEFF Research Database (Denmark)

Thind, Vandana; Sharma, Shivani; Minwer, M H

2015-01-01

Energy, Power and efficiency are very much related to each other. To make any system efficient, Power consumed by it must be minimized or we can say that power dissipation should be less. In our research we tried to make a energy efficient router design on FPGA by varying junction temperature...

Power electronics for renewable energy systems

DEFF Research Database (Denmark)

Iov, Florin; Blaabjerg, Frede

2009-01-01

sources from the conventional, fossil (and short term) based energy sources to renewable energy resources. Another is to use high efficient power electronics in power generation, power transmission/distribution and end-user application. This paper discuss some of the most emerging renewable energy sources......, wind energy and photovoltaics, which by means of power electronics are changing from being minor energy sources to be acting as important power sources in the energy system....

Energy efficiency opportunities in Hotels

Directory of Open Access Journals (Sweden)

Dina Said

2017-03-01

Full Text Available According to the statistics in Egypt (2013, the number of hotels is 1193, about 407 of them have contracted power greater than 500 kW.Air conditioning, lighting, water heating and refrigeration represent the main activities demanding electrical energy in hotel business.The energy consumption per night spend changes a lot, depending on various factors; facilities provided, category of hotel, occupancy , geographical situation, weather conditions, nationality of clients, design and control of the installations.Energy benchmarking is an internal management tool designed to provide ongoing, reliable and verifiable tracking on the hotels performance. The most useful performance indicator (or Energy Efficiency Benchmarking of hotels are: Lighting Power Density (LPD in W (for lighting/m2, and energy intensity (kWh/m2/ y.There are multiple benefits for improving energy in hotel business; reduces the hotel's operating cost, reduces climate change risks and promotes green tourism.Energy efficiency opportunities are low-cost measures and cost- effective investments.   There are many energy saving opportunities for lighting in hotel's guest rooms as well as the more obvious savings in lobbies and exterior lighting areas. Behavior campaigns can yield substantial energy savings, both through the guests and housekeeper behavior. Encouraging housekeepers to use natural light during room cleaning is a simple first step to implement energy saving program.This paper presents the energy efficiency guidelines and energy benchmarking for hotels. Also a case study showing how the energy efficiency program implemented is presented. 

A Low Power Consumption Algorithm for Efficient Energy Consumption in ZigBee Motes.

Science.gov (United States)

Vaquerizo-Hdez, Daniel; Muñoz, Pablo; R-Moreno, María D; F Barrero, David

2017-09-22

Wireless Sensor Networks (WSNs) are becoming increasingly popular since they can gather information from different locations without wires. This advantage is exploited in applications such as robotic systems, telecare, domotic or smart cities, among others. To gain independence from the electricity grid, WSNs devices are equipped with batteries, therefore their operational time is determined by the time that the batteries can power on the device. As a consequence, engineers must consider low energy consumption as a critical objective to design WSNs. Several approaches can be taken to make efficient use of energy in WSNs, for instance low-duty-cycling sensor networks (LDC-WSN). Based on the LDC-WSNs, we present LOKA, a LOw power Konsumption Algorithm to minimize WSNs energy consumption using different power modes in a sensor mote. The contribution of the work is a novel algorithm called LOKA that implements two duty-cycling mechanisms using the end-device of the ZigBee protocol (of the Application Support Sublayer) and an external microcontroller (Cortex M0+) in order to minimize the energy consumption of a delay tolerant networking. Experiments show that using LOKA, the energy required by the sensor device is reduced to half with respect to the same sensor device without using LOKA.

A Low Power Consumption Algorithm for Efficient Energy Consumption in ZigBee Motes

Directory of Open Access Journals (Sweden)

Daniel Vaquerizo-Hdez

2017-09-01

Full Text Available Wireless Sensor Networks (WSNs are becoming increasingly popular since they can gather information from different locations without wires. This advantage is exploited in applications such as robotic systems, telecare, domotic or smart cities, among others. To gain independence from the electricity grid, WSNs devices are equipped with batteries, therefore their operational time is determined by the time that the batteries can power on the device. As a consequence, engineers must consider low energy consumption as a critical objective to design WSNs. Several approaches can be taken to make efficient use of energy in WSNs, for instance low-duty-cycling sensor networks (LDC-WSN. Based on the LDC-WSNs, we present LOKA, a LOw power Konsumption Algorithm to minimize WSNs energy consumption using different power modes in a sensor mote. The contribution of the work is a novel algorithm called LOKA that implements two duty-cycling mechanisms using the end-device of the ZigBee protocol (of the Application Support Sublayer and an external microcontroller (Cortex M0+ in order to minimize the energy consumption of a delay tolerant networking. Experiments show that using LOKA, the energy required by the sensor device is reduced to half with respect to the same sensor device without using LOKA.

Energy and environmental efficiency in competitive power markets

International Nuclear Information System (INIS)

Warwick, W.M.

1995-02-01

For years the electric utility industry operated as a regulated monopoly, largely immune to market forces except those of competing fuels. That era came to an end with the Public Utilities Regulatory Policy Act (PURPA) of 1974, which created a market for non-utility generated power. Within twenty years, non-regulated, non-utility generators had become the primary supplier of new energy resources. Their market power is matched by their political power, as evidenced in the Energy Policy Act of 1994 (EPAct), which requires open access to utility transmission lines to facilitate inter-utility bulk power sales. The conventional wisdom is that active wholesale power markets with competition among alternative generators will lead to lower power-development costs and cheaper retail power prices. The trend towards alternative bulk power sources at low prices intersects with large retail power customers' interest in accessing alternative power supplies. In most cases, these alternatives to local utilities are at a lower cost than retail rates. For the most part, proponents of generation competition have remained silent about potential environmental consequences. However, skeptics of increased competition, including major environmental groups, cite environmental impacts among their concerns. This report examines these concerns

Effects of upgrading systems on energy conversion efficiency of a gasifier - fuel cell - gas turbine power plant

International Nuclear Information System (INIS)

Pedrazzi, Simone; Allesina, Giulio; Tartarini, Paolo

2016-01-01

Highlights: • An advanced gasifier-SOFC-MGT system is modeled. • An overall electrical efficiency of 32.81% is reached. • Influence of all the sub-system modeled on the power plant efficiency is discussed. • Compression storage of syngas is taken into account. - Abstract: This work focuses on a DG-SOFC-MGT (downdraft gasifier - solid oxide fuel cell - micro gas turbine) power plant for electrical energy production and investigates two possible performance-upgrading systems: polyphenylene oxide (PPO) membrane and zeolite filters. The first is used to produce oxygen-enriched air used in the reactor, while the latter separates the CO_2 content from the syngas. In order to prevent power plant shutdowns during the gasifier reactor scheduled maintenance, the system is equipped with a gas storage tank. The generation unit consists of a SOFC-MGT system characterized by higher electrical efficiency when compared to conventional power production technology (IC engines, ORC and EFGT). Poplar wood chips with 10% of total moisture are used as feedstock. Four different combinations with and without PPO and zeolite filtrations are simulated and discussed. One-year energy and power simulation were used as basis for comparison between all the cases analyzed. The modeling of the gasification reactions gives results consistent with literature about oxygen-enriched processes. Results showed that the highest electrical efficiency obtained is 32.81%. This value is reached by the power plant equipped only with PPO membrane filtration. Contrary to the PPO filtering, zeolite filtration does not increase the SOFC-MGT unit performance while it affects the energy balance with high auxiliary electrical consumption. This solution can be considered valuable only for future work coupling a CO_2 sequestration system to the power plant.

Efficiency Evaluation of Energy Systems

CERN Document Server

Kanoğlu, Mehmet; Dinçer, İbrahim

2012-01-01

Efficiency is one of the most frequently used terms in thermodynamics, and it indicates how well an energy conversion or process is accomplished. Efficiency is also one of the most frequently misused terms in thermodynamics and is often a source of misunderstanding. This is because efficiency is often used without being properly defined first. This book intends to provide a comprehensive evaluation of various efficiencies used for energy transfer and conversion systems including steady-flow energy devices (turbines, compressors, pumps, nozzles, heat exchangers, etc.), various power plants, cogeneration plants, and refrigeration systems. The book will cover first-law (energy based) and second-law (exergy based) efficiencies and provide a comprehensive understanding of their implications. It will help minimize the widespread misuse of efficiencies among students and researchers in energy field by using an intuitive and unified approach for defining efficiencies. The book will be particularly useful for a clear ...

High Efficiency Power Converter for Low Voltage High Power Applications

DEFF Research Database (Denmark)

Nymand, Morten

The topic of this thesis is the design of high efficiency power electronic dc-to-dc converters for high-power, low-input-voltage to high-output-voltage applications. These converters are increasingly required for emerging sustainable energy systems such as fuel cell, battery or photo voltaic based......, and remote power generation for light towers, camper vans, boats, beacons, and buoys etc. A review of current state-of-the-art is presented. The best performing converters achieve moderately high peak efficiencies at high input voltage and medium power level. However, system dimensioning and cost are often...

Power Electronics Control of Wind Energy in Distributed Power System

DEFF Research Database (Denmark)

Iov, Florin; Ciobotaru, Mihai; Blaabjerg, Frede

2008-01-01

is to change the electrical power production sources from the conventional, fossil (and short term) based energy sources to renewable energy resources. The other is to use high efficient power electronics in power generation, power transmission/distribution and end-user application. This paper discuss the most...... emerging renewable energy sources, wind energy, which by means of power electronics are changing from being a minor energy source to be acting as an important power source in the energy system. Power electronics is the enabling technology and the presentation will cover the development in wind turbine...... technology from kW to MW, discuss which power electronic solutions are most feasible and used today....

Evaluation of the energy efficiency of combined cycle gas turbine. Case study of Tashkent thermal power plant, Uzbekistan

International Nuclear Information System (INIS)

Aminov, Zarif; Nakagoshi, Nobukazu; Xuan, Tran Dang; Higashi, Osamu; Alikulov, Khusniddin

2016-01-01

Highlights: • The combined cycle power plant (CCPP) has a steam turbine and a gas turbine. • Fossil fuel savings and reduction of the CCGT of was evaluated. • The performance of a three pressure CCGT is modelled under different modes. • Energy efficiency of the combined cycle was 58.28%. • An annual reduction of 1760.18 tNO_x/annum and 981.25 ktCO_2/annum can be achieved. - Abstract: The power generation of Tashkent Thermal Power Plant (TPP) is based on conventional power units. Moreover, the facility suffers from limited efficiency in electricity generation. The plant was constructed during the Soviet era. Furthermore, the power plant is being used for inter-hour power generation regulation. As a result, the efficiency can be reduced by increasing specific fuel consumption. This research focuses on the evaluation of the energy efficiency of the combined cycle gas turbine (CCGT) for the Tashkent TPP. Specifically, the objective is an evaluation of fossil fuel savings and reduction of CO_2 and NO_x emissions with the using CCGT technology at conventional power plant. The proposed combined cycle power plant (CCPP) includes an existing steam turbine (ST) with 160 MW capacity, heat recovery steam generator (HRSG), and gas turbine (GT) technology with 300 MW capacity. The performance of a three pressure CCGT is modelled under different modes. As a result, the efficiency of the combined cycle was evaluated at 58.28%, while the conventional cycle had an efficiency of 34.5%. We can achieve an annual reduction of 1760.18 tNO_x/annum and 981.25 ktCO_2/annum.

Energy Conversion Alternatives Study (ECAS), Westinghouse phase 1. Volume 5: Combined gas-steam turbine cycles. [energy conversion efficiency in electric power plants

Science.gov (United States)

Amos, D. J.; Foster-Pegg, R. W.; Lee, R. M.

1976-01-01

The energy conversion efficiency of gas-steam turbine cycles was investigated for selected combined cycle power plants. Results indicate that it is possible for combined cycle gas-steam turbine power plants to have efficiencies several point higher than conventional steam plants. Induction of low pressure steam into the steam turbine is shown to improve the plant efficiency. Post firing of the boiler of a high temperature combined cycle plant is found to increase net power but to worsen efficiency. A gas turbine pressure ratio of 12 to 1 was found to be close to optimum at all gas turbine inlet temperatures that were studied. The coal using combined cycle plant with an integrated low-Btu gasifier was calculated to have a plant efficiency of 43.6%, a capitalization of $497/kW, and a cost of electricity of 6.75 mills/MJ (24.3 mills/kwh). This combined cycle plant should be considered for base load power generation.

A data envelopment analysis for energy efficiency of coal-fired power units in China

International Nuclear Information System (INIS)

Song, Chenxi; Li, Mingjia; Zhang, Fan; He, Ya-Ling; Tao, Wen-Quan

2015-01-01

Highlights: • Two kinds of energy efficiency (EE) indices are analyzed and compared. • The influence degrees of different uncontrollable factors on EE are compared. • The influence of load factor on special EE is 82.6% larger than capacity factor. • The influence of cooling method on special EE is 90.32% larger than steam pressure. • The generalized EE indicator is more recommended by the authors. - Abstract: In this article, the non-parametric data envelopment analysis method (DEA) is employed to evaluate energy efficiency (EE) of 34 coal-fired power units in China. Input-oriented CCR (Charnes, Cooper and Rhodes) model is used for EE analysis. Two efficiency indices, generalized EE and special EE are defined and analyzed. The generalized EE is calculated based on four input parameters: coal consumption, oil consumption, water consumption and auxiliary power consumption by power units. The special EE is only based on two input parameters: coal consumption and auxiliary power consumption. Relations between these two EE indices and non-comparable factors including quality of coal, load factor, capacity factor, parameters of main steam and cooling method are studied. Comparison between EE evaluation results of the two indices is conducted. Results show that these two kinds of EE are more sensitive to the load factor than the capacity factor. The influence of the cooling method on EE is larger than that of main steam parameter. The influence of non-comparable factors on the special EE is stronger than that on the generalized EE

U.S. Department of Energy Solar Decathlon: Challenging Students to Build Energy Efficient, Cost-Effective, and Attractive Solar-Powered Houses

Energy Technology Data Exchange (ETDEWEB)

Simon, J.

2012-01-01

The U.S. Department of Energy Solar Decathlon challenges collegiate teams to design, build, and operate solar-powered houses that are cost-effective, energy-efficient, and attractive. The winner of the competition is the team that best blends affordability, consumer appeal, and design excellence with optimal energy production and maximum efficiency. The paper discusses the solutions developed for the event. We believe that the solutions implemented for Solar Decathlon 2011 represent current trends and that by analyzing, critiquing, and exposing the solutions pursued, the industry can become better suited to address challenges of the future. Constructing a solar community using high-efficiency design and unique materials while remaining code compliant, safe, and effective results in solutions that are market relevant, important, and interesting to the industry as a whole.

The green computing book tackling energy efficiency at large scale

CERN Document Server

Feng, Wu-chun

2014-01-01

Low-Power, Massively Parallel, Energy-Efficient Supercomputers The Blue Gene TeamCompiler-Driven Energy Efficiency Mahmut Kandemir and Shekhar Srikantaiah An Adaptive Run-Time System for Improving Energy Efficiency Chung-Hsing Hsu, Wu-chun Feng, and Stephen W. PooleEnergy-Efficient Multithreading through Run-Time Adaptation Exploring Trade-Offs between Energy Savings and Reliability in Storage Systems Ali R. Butt, Puranjoy Bhattacharjee, Guanying Wang, and Chris GniadyCross-Layer Power Management Zhikui Wang and Parthasarathy Ranganathan Energy-Efficient Virtualized Systems Ripal Nathuji and K

Energy efficiency. Lever for the German energy transition

International Nuclear Information System (INIS)

Persem, Melanie; Roesner, Sven

2014-05-01

This document provides some key data on energy consumption in housing and public buildings, indicates the national German objectives in terms of reduction of energy consumption, of reduction of electricity consumption, of energy efficiency, and of evolution of energy consumption in housing and public buildings and in the transport sector. It gives some data related to energy saving and achievements: energy efficiency of the German economy, improvements in housing energy efficiency and insulation, financial support for low income households, reduction of energy consumption within small-medium enterprises, the public sector, the data processing sector and public lighting, and energy saving potential by renewal of public buildings. It indicates the main measures and arrangements: information, support programs for enterprises, local communities and individuals. A graph illustrates a comparison of shares of household power consumption in France and in Germany

Energy efficiency analysis and impact evaluation of the application of thermoelectric power cycle to today's CHP systems

DEFF Research Database (Denmark)

Chen, Min; Lund, Henrik; Rosendahl, Lasse

2010-01-01

benefits, together with the environmental impact of this deployment, will then be estimated. By using the Danish thermal energy system as a paradigm, this paper will consider the TEG application to district heating systems and power plants through the EnergyPLAN model, which has been created to design......High efficiency thermoelectric generators (TEG) can recover waste heat from both industrial and private sectors. Thus, the development and deployment of TEG may represent one of the main drives for technological change and fuel substitution. This paper will present an analysis of system efficiency...... configurations for combustion systems. The feasible deployment of TEG in various CHP plants will be examined in terms of heat source temperature range, influences on CHP power specification and thermal environment, as well as potential benefits. The overall conversion efficiency improvements and economic...

The role of the power/efficiency misconception in the rebound effect's size debate: Does efficiency actually lead to a power enhancement?

Energy Technology Data Exchange (ETDEWEB)

Ruzzenenti, F. [Center for Complex System Investigations, University of Siena (Italy); Basosi, R. [Center for Complex System Investigations, University of Siena (Italy); Department of Chemistry, University of Siena (Italy)

2008-09-15

This paper addresses the question of whether the rebound effect's size is bigger or smaller than one. After a brief review of the related economic literature, a thermodynamic perspective tackles this topic by demonstrating that the dispute over the size of the rebound effect relies on a misconception of the thermodynamic nature of energy efficiency. The dichotomy, in fact, concerns the relationship between efficiency and power output rather than the scale of the economic side effects generated by energy efficiency mutations. Early intuitions of the dichotomy efficiency/power belong to the pioneering works of Stanley Jevons, in the field of economics, and Alfred Lotka in that of biology. Their findings are here approached using the basis of finite-time thermodynamics with a simple amendment, the addition of the time variable to the Carnot machinery. The model shows how a process of power maximization always leads to a sub-optimal efficiency level and additionally, that any efficiency improvement, in the context of low energy costs, will shift the power output of the machine instead of reducing energy consumption. A case study taken from the transport system is presented to elucidate this argument. (author)

77 FR 38743 - Energy Efficiency Program for Consumer Products: Energy Conservation Standards for Battery...

Science.gov (United States)

2012-06-29

... Efficiency Program for Consumer Products: Energy Conservation Standards for Battery Chargers and External Power Supplies AGENCY: Office of Energy Efficiency and Renewable Energy, Department of Energy. ACTION... Energy Efficiency and Renewable Energy, Building Technologies Program, EE-2J, 1000 Independence Avenue SW...

Raising the Profile of Energy Efficiency in China

Energy Technology Data Exchange (ETDEWEB)

NONE

2006-07-01

Reducing standby power use in China. How much does China stand to gain from greater energy efficiency? The example of improved standby power efficiency in household appliances provides a useful indicator. IEA analysis projects that eight or nine 1-GW power plants could be struck off Chinas list of immediate capacity needs for the period to 2020 if energy-efficient standby devices were vigorously promoted. This impressive finding emerges from this paper. The paper reviews experience with tackling standby power consumption in OECD countries and models implementation of similar action in China and Shanghai. Its scenarios quantify the significant potential gains from standby power conservation campaigns and mandatory regulations.

A Cognitive Radio-Based Energy-Efficient System for Power Transmission Line Monitoring in Smart Grids

Directory of Open Access Journals (Sweden)

Saeed Ahmed

2017-01-01

Full Text Available The research in industry and academia on smart grids is predominantly focused on the regulation of generated power and management of its consumption. Because transmission of bulk-generated power to the consumer is immensely reliant on secure and efficient transmission grids, comprising huge electrical and mechanical assets spanning a vast geographic area, there is an impending need to focus on the transmission grids as well. Despite the challenges in wireless technologies for SGs, cognitive radio networks are considered promising for provisioning of communications services to SGs. In this paper, first, we present an IEEE 802.22 wireless regional area network cognitive radio-based network model for smart monitoring of transmission lines. Then, for a prolonged lifetime of battery finite monitoring network, we formulate the spectrum resource allocation problem as an energy efficiency maximization problem, which is a nonlinear integer programming problem. To solve this problem in an easier way, we propose an energy-efficient resource-assignment scheme based on the Hungarian method. Performance analysis shows that, compared to a pure opportunistic assignment scheme with a throughput maximization objective and compared to a random scheme, the proposed scheme results in an enhanced lifetime while consuming less battery energy without compromising throughput performance.

How organizational and global factors condition the effects of energy efficiency on CO_2 emission rebounds among the world's power plants

International Nuclear Information System (INIS)

Grant, Don; Jorgenson, Andrew K.; Longhofer, Wesley

2016-01-01

The United Nations Intergovernmental Panel on Climate Change (IPCC), the International Energy Agency (IEA), and several nations suggest that energy efficiency is an effective strategy for reducing energy consumption and associated greenhouse gas emissions. Skeptics contend that because efficiency lowers the price of energy and energy services, it may actually increase demand for them, causing total emissions to rise. While both sides of this debate have researched the magnitude of these so-called rebound effects among end-use consumers, researchers have paid less attention to the conditions under which direct rebounds cause CO_2 emissions to rise among industrial producers. In particular, researchers have yet to explore how organizational and global factors might condition the effects of efficiency on emissions among power plants, the world's most concentrated sources of anthropogenic greenhouse gases. Here we use a unique dataset containing nearly every fossil-fuel power plant in the world to determine whether the impact of efficiency on emissions varies by plants' age, size, and location in global economic and normative systems. Findings reveal that each of these factors has a significant interaction with efficiency and thus shapes environmentally destructive rebound effects. - Highlights: •Skeptics charge that energy efficiency may actually cause CO_2 emissions to rise. •Few have examined whether such rebound effects occur among power plants. •Little also known about whether plants' organizational and global characteristics condition rebounds. •Conduct first analysis of rebound effects among the world's power plants. •Rebounds found to depend on plants' age, size, and location in international economic and normative systems.

Thermodynamic and energy efficiency analysis of power generation from natural salinity gradients by pressure retarded osmosis.

Science.gov (United States)

Yip, Ngai Yin; Elimelech, Menachem

2012-05-01

The Gibbs free energy of mixing dissipated when fresh river water flows into the sea can be harnessed for sustainable power generation. Pressure retarded osmosis (PRO) is one of the methods proposed to generate power from natural salinity gradients. In this study, we carry out a thermodynamic and energy efficiency analysis of PRO work extraction. First, we present a reversible thermodynamic model for PRO and verify that the theoretical maximum extractable work in a reversible PRO process is identical to the Gibbs free energy of mixing. Work extraction in an irreversible constant-pressure PRO process is then examined. We derive an expression for the maximum extractable work in a constant-pressure PRO process and show that it is less than the ideal work (i.e., Gibbs free energy of mixing) due to inefficiencies intrinsic to the process. These inherent inefficiencies are attributed to (i) frictional losses required to overcome hydraulic resistance and drive water permeation and (ii) unutilized energy due to the discontinuation of water permeation when the osmotic pressure difference becomes equal to the applied hydraulic pressure. The highest extractable work in constant-pressure PRO with a seawater draw solution and river water feed solution is 0.75 kWh/m(3) while the free energy of mixing is 0.81 kWh/m(3)-a thermodynamic extraction efficiency of 91.1%. Our analysis further reveals that the operational objective to achieve high power density in a practical PRO process is inconsistent with the goal of maximum energy extraction. This study demonstrates thermodynamic and energetic approaches for PRO and offers insights on actual energy accessible for utilization in PRO power generation through salinity gradients. © 2012 American Chemical Society

Case Study on Incentive Mechanism of Energy Efficiency Retrofit in Coal-Fueled Power Plant in China

Science.gov (United States)

Yuan, Donghai; Guo, Xujing; Cao, Yuan; He, Liansheng; Wang, Jinggang; Xi, Beidou; Li, Junqi; Ma, Wenlin; Zhang, Mingshun

2012-01-01

An ordinary steam turbine retrofit project is selected as a case study; through the retrofit, the project activities will generate emission reductions within the power grid for about 92,463 tCO2e per annum. The internal rate of return (IRR) of the project is only −0.41% without the revenue of carbon credits, for example, CERs, which is much lower than the benchmark value of 8%. Only when the unit price of carbon credit reaches 125 CNY/tCO2, the IRR could reach the benchmark and an effective carbon tax needs to increase the price of carbon to 243 CNY/tce in order to make the project financially feasible. Design of incentive mechanism will help these low efficiency enterprises improve efficiency and reduce CO2 emissions, which can provide the power plants sufficient incentive to implement energy efficiency retrofit project in existing coal-fuel power generation-units, and we hope it will make a good demonstration for the other low efficiency coal-fueled power generation units in China. PMID:23365532

Case Study on Incentive Mechanism of Energy Efficiency Retrofit in Coal-Fueled Power Plant in China

Directory of Open Access Journals (Sweden)

Donghai Yuan

2012-01-01

Full Text Available An ordinary steam turbine retrofit project is selected as a case study; through the retrofit, the project activities will generate emission reductions within the power grid for about 92,463 tCO2e per annum. The internal rate of return (IRR of the project is only −0.41% without the revenue of carbon credits, for example, CERs, which is much lower than the benchmark value of 8%. Only when the unit price of carbon credit reaches 125 CNY/tCO2, the IRR could reach the benchmark and an effective carbon tax needs to increase the price of carbon to 243 CNY/tce in order to make the project financially feasible. Design of incentive mechanism will help these low efficiency enterprises improve efficiency and reduce CO2 emissions, which can provide the power plants sufficient incentive to implement energy efficiency retrofit project in existing coal-fuel power generation-units, and we hope it will make a good demonstration for the other low efficiency coal-fueled power generation units in China.

Case study on incentive mechanism of energy efficiency retrofit in coal-fueled power plant in China.

Science.gov (United States)

Yuan, Donghai; Guo, Xujing; Cao, Yuan; He, Liansheng; Wang, Jinggang; Xi, Beidou; Li, Junqi; Ma, Wenlin; Zhang, Mingshun

2012-01-01

An ordinary steam turbine retrofit project is selected as a case study; through the retrofit, the project activities will generate emission reductions within the power grid for about 92,463 tCO(2)e per annum. The internal rate of return (IRR) of the project is only -0.41% without the revenue of carbon credits, for example, CERs, which is much lower than the benchmark value of 8%. Only when the unit price of carbon credit reaches 125 CNY/tCO(2), the IRR could reach the benchmark and an effective carbon tax needs to increase the price of carbon to 243 CNY/tce in order to make the project financially feasible. Design of incentive mechanism will help these low efficiency enterprises improve efficiency and reduce CO(2) emissions, which can provide the power plants sufficient incentive to implement energy efficiency retrofit project in existing coal-fuel power generation-units, and we hope it will make a good demonstration for the other low efficiency coal-fueled power generation units in China.

Innovations in Multi-Level Governance for Energy Efficiency

Energy Technology Data Exchange (ETDEWEB)

NONE

2009-07-01

Recent IEA analysis highlights member countries' significant progress with developing energy efficiency policy (International Energy Agency 2009). The 28 member countries of the IEA are engaged in promoting innovative financial instruments, energy efficiency strategies and action plans. They are designing policies to promote energy efficiency in buildings, the adoption of standby power, the phase out of inefficient lighting, proper tyre-inflation and related policies, and energy efficiency in utilities.

Innovations in Multi-Level Governance for Energy Efficiency

Energy Technology Data Exchange (ETDEWEB)

NONE

2009-07-01

Recent IEA analysis highlights member countries' significant progress with developing energy efficiency policy (International Energy Agency 2009). The 28 member countries of the IEA are engaged in promoting innovative financial instruments, energy efficiency strategies and action plans. They are designing policies to promote energy efficiency in buildings, the adoption of standby power, the phase out of inefficient lighting, proper tyre-inflation and related policies, and energy efficiency in utilities.

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.

Simulation Based Data Reconciliation for Monitoring Power Plant Efficiency

International Nuclear Information System (INIS)

Park, Sang Jun; Heo, Gyun Young

2010-01-01

Power plant efficiency is analyzed by using measured values, mass/energy balance principles, and several correlations. Since the measured values can have uncertainty depending on the accuracy of instrumentation, the results of plant efficiency should definitely have uncertainty. The certainty may occur due to either the randomness or the malfunctions of a process. In order to improve the accuracy of efficiency analysis, the data reconciliation (DR) is expected as a good candidate because the mathematical algorithm of the DR is based on the first principles such as mass and energy balance considering the uncertainty of instrumentation. It should be noted that the mass and energy balance model for analyzing power plant efficiency is equivalent to a steady-state simulation of a plant system. Therefore the DR for efficiency analysis necessitates the simulation which can deal with the uncertainty of instrumentation. This study will propose the algorithm of the simulation based DR which is applicable to power plant efficiency monitoring

Energy Efficient Payload Aggregation in WSNs

Directory of Open Access Journals (Sweden)

Ákos MILÁNKOVICH

2015-06-01

Full Text Available Creating wireless sensor networks requires a different approach than traditional communication networks because energy efficiency plays a key role in sensor networks, which consist of devices without external power. The amount of energy used determines the lifetime of these devices. In most cases data packets are less sensitive to delay, thus can be aggregated, making it possible to gather more useful information reducing the energy required to transmit information. This article discusses the energy efficiency of different Forward Error Correction algorithms and presents a method to calculate the optimal amount of aggregation of the data packets in terms of power consumption, while taking into account the Bit Error Rate characteristics of the wireless channel. The contribution of this paper is a general method to improve the energy efficiency of wireless sensor networks by using the optimal amount of aggregation in case of different Forward Error Correction codes and channel characteristics. The presented results can be applied to any packet-based wireless protocol.

Energy efficiency analysis and implementation of AES on an FPGA

Science.gov (United States)

Kenney, David

The Advanced Encryption Standard (AES) was developed by Joan Daemen and Vincent Rjimen and endorsed by the National Institute of Standards and Technology in 2001. It was designed to replace the aging Data Encryption Standard (DES) and be useful for a wide range of applications with varying throughput, area, power dissipation and energy consumption requirements. Field Programmable Gate Arrays (FPGAs) are flexible and reconfigurable integrated circuits that are useful for many different applications including the implementation of AES. Though they are highly flexible, FPGAs are often less efficient than Application Specific Integrated Circuits (ASICs); they tend to operate slower, take up more space and dissipate more power. There have been many FPGA AES implementations that focus on obtaining high throughput or low area usage, but very little research done in the area of low power or energy efficient FPGA based AES; in fact, it is rare for estimates on power dissipation to be made at all. This thesis presents a methodology to evaluate the energy efficiency of FPGA based AES designs and proposes a novel FPGA AES implementation which is highly flexible and energy efficient. The proposed methodology is implemented as part of a novel scripting tool, the AES Energy Analyzer, which is able to fully characterize the power dissipation and energy efficiency of FPGA based AES designs. Additionally, this thesis introduces a new FPGA power reduction technique called Opportunistic Combinational Operand Gating (OCOG) which is used in the proposed energy efficient implementation. The AES Energy Analyzer was able to estimate the power dissipation and energy efficiency of the proposed AES design during its most commonly performed operations. It was found that the proposed implementation consumes less energy per operation than any previous FPGA based AES implementations that included power estimations. Finally, the use of Opportunistic Combinational Operand Gating on an AES cipher

Statistical-QoS Guaranteed Energy Efficiency Optimization for Energy Harvesting Wireless Sensor Networks.

Science.gov (United States)

Gao, Ya; Cheng, Wenchi; Zhang, Hailin

2017-08-23

Energy harvesting, which offers a never-ending energy supply, has emerged as a prominent technology to prolong the lifetime and reduce costs for the battery-powered wireless sensor networks. However, how to improve the energy efficiency while guaranteeing the quality of service (QoS) for energy harvesting based wireless sensor networks is still an open problem. In this paper, we develop statistical delay-bounded QoS-driven power control policies to maximize the effective energy efficiency (EEE), which is defined as the spectrum efficiency under given specified QoS constraints per unit harvested energy, for energy harvesting based wireless sensor networks. For the battery-infinite wireless sensor networks, our developed QoS-driven power control policy converges to the Energy harvesting Water Filling (E-WF) scheme and the Energy harvesting Channel Inversion (E-CI) scheme under the very loose and stringent QoS constraints, respectively. For the battery-finite wireless sensor networks, our developed QoS-driven power control policy becomes the Truncated energy harvesting Water Filling (T-WF) scheme and the Truncated energy harvesting Channel Inversion (T-CI) scheme under the very loose and stringent QoS constraints, respectively. Furthermore, we evaluate the outage probabilities to theoretically analyze the performance of our developed QoS-driven power control policies. The obtained numerical results validate our analysis and show that our developed optimal power control policies can optimize the EEE over energy harvesting based wireless sensor networks.

An Empirical LTE Smartphone Power Model with a View to Energy Efficiency Evolution

DEFF Research Database (Denmark)

Lauridsen, Mads; Noël, Laurent; Sørensen, Troels Bundgaard

2014-01-01

measurements made on state-of-the-art LTE smartphones. Discontinuous Reception (DRX) sleep mode is also modeled, because it is one of the most effective methods to improve smartphone battery life. Energy efficiency has generally improved with each Radio Access Technology (RAT) generation, and to see......Smartphone users struggle with short battery life, and this affects their device satisfaction level and usage of the network. To evaluate how chipset manufacturers and mobile network operators can improve the battery life, we propose a Long Term Evolution (LTE) smartphone power model. The idea...... this evolution, we compare the energy efficiency of the latest LTE devices with devices based on Enhanced Data rates for GSM Evolution (EDGE), High Speed Packet Access (HSPA), and Wi-Fi*. With further generations of RAT systems we expect further improvements. To this end, we discuss the new LTE features, Carrier...

State-level benefits of energy efficiency

International Nuclear Information System (INIS)

Tonn, Bruce; Peretz, Jean H.

2007-01-01

This paper describes benefits attributable to state-level energy efficiency programs. Nationwide, state-level energy efficiency programs have targeted all sectors of the economy and have employed a wide range of methods to promote energy efficiency. Standard residential and industrial programs typically identify between 20% and 30% energy savings in homes and plants, respectively. Over a 20-year period of time, an average state that aggressively pursues even a limited array of energy efficiency programs can potentially reduce total state energy use by as much as 20%. Well-designed energy efficiency programs can be expected to help overcome numerous barriers to the market penetration of energy efficient technologies and accelerate the market penetration of the technologies. Energy efficiency programs are cost-effective; typical benefit-cost ratios exceed 3:1 and are much higher when non-energy and macroeconomic benefits are included. Indeed, energy efficiency and associated programs and investments can create significant numbers of new jobs and enhance state tax revenues. Several states have incorporated energy efficiency into their economic development programs. It should also be noted that increasing amounts of venture capital are being invested in the energy sector in general and in specific technologies like solar power in particular. (author)

State-Level Benefits of Energy Efficiency

Energy Technology Data Exchange (ETDEWEB)

Tonn, Bruce Edward [ORNL

2007-02-01

This report describes benefits attributable to state-level energy efficiency programs. Nationwide, state-level energy efficiency programs have targeted all sectors of the economy and have employed a wide range of methods to promote energy efficiency. Standard residential and industrial programs typically identify between 20 to 30% energy savings in homes and plants, respectively. Over a 20 year period of time, an average state that aggressively pursues even a limited array of energy efficiency programs can potentially reduce total state energy use by as much as 20%. Benefit-cost ratios of effective energy efficiency programs typically exceed 3 to 1 and are much higher when non-energy and macroeconomic benefits are included. Indeed, energy efficiency and associated programs and investments can create significant numbers of new jobs and enhance state tax revenues. Several states have incorporated energy efficiency into their economic development programs. It should also be noted that increasing amounts of venture capital are being invested in the energy sector in general and in specific technologies like solar power in particular. Well-designed energy efficiency programs can be expected to help overcome numerous barriers to the market penetration of energy efficient technologies and accelerate the market penetration of the technologies.

Computation of full energy peak efficiency for nuclear power plant radioactive plume using remote scintillation gamma-ray spectrometry.

Science.gov (United States)

Grozdov, D S; Kolotov, V P; Lavrukhin, Yu E

2016-04-01

A method of full energy peak efficiency estimation in the space around scintillation detector, including the presence of a collimator, has been developed. It is based on a mathematical convolution of the experimental results with the following data extrapolation. The efficiency data showed the average uncertainty less than 10%. Software to calculate integral efficiency for nuclear power plant plume was elaborated. The paper also provides results of nuclear power plant plume height estimation by analysis of the spectral data. Copyright © 2016 Elsevier Ltd. All rights reserved.

S-CO2 for efficient power generation with energy storage

OpenAIRE

Cerio Vera, Marta

2016-01-01

Supercritical CO2 (s-CO2) power cycle has gained interest for concentrating solar power (CSP) application in the last decade to overcome the current low efficiency and high costs of the plants. This cycle is a potential option to replace the steam Rankine cycle due to its higher efficiency, more compact turbomachinery and possibility of including heat storage and direct heating. The purpose of this project is to determine the suitability of integrating s-CO2 power cycle into CSP plants with e...

Deployment of energy efficient technologies in developing countries

International Nuclear Information System (INIS)

Koch, H.J.

2000-01-01

Efficient and reliable power generation and power distribution represent the engine for economic growth in developing countries. A vast majority of the population in these countries does not have access to electricity, and those that do are often faced with an unreliable power distribution system. Now is the ideal time to transfer efficient energy technologies which also adhere to environmental standards. There are a myriad of inexpensive ways to avoid energy losses, such as cogeneration, the addition of natural gas turbines to coal-fired heating boilers. Even power generation itself can be more efficient. These improvements would encourage the financing world to pay closer attention and invest more rapidly in projects aimed at improving efficient power generation. The International Energy Agency was created in 1974 with the participation of 25 countries, and its mandate was expanded to include the deployment of clean and efficient energy technologies in developing countries. Technology transfer involves more than the shipping of equipment combined with some expert assistance. It involves the active participation of several partners, from the private sector, governments, non-governmental organizations (NGO), and academic institutions. The objective is to empower the recipient population, thereby reducing the need for imports. It is a joint international effort where the results benefit all participants. The author also discussed the Climate Technology Initiative (CTI) with the aim of disseminating information concerning climate change in the hope of reducing global emissions of greenhouse gases. Discussions to assist countries in the examination of avenues open to them in the field of energy are also fostered. Training in energy efficient technologies represents an important aspect of the role of CTI. It applies to decision makers to help them establish appropriate guidelines and regulations with regard to these technologies. Sustainable development can be achieved

High Efficiency Power Converter for Low Voltage High Power Applications

DEFF Research Database (Denmark)

Nymand, Morten

The topic of this thesis is the design of high efficiency power electronic dc-to-dc converters for high-power, low-input-voltage to high-output-voltage applications. These converters are increasingly required for emerging sustainable energy systems such as fuel cell, battery or photo voltaic based...

Energy efficient data centers

Energy Technology Data Exchange (ETDEWEB)

Tschudi, William; Xu, Tengfang; Sartor, Dale; Koomey, Jon; Nordman, Bruce; Sezgen, Osman

2004-03-30

Data Center facilities, prevalent in many industries and institutions are essential to California's economy. Energy intensive data centers are crucial to California's industries, and many other institutions (such as universities) in the state, and they play an important role in the constantly evolving communications industry. To better understand the impact of the energy requirements and energy efficiency improvement potential in these facilities, the California Energy Commission's PIER Industrial Program initiated this project with two primary focus areas: First, to characterize current data center electricity use; and secondly, to develop a research ''roadmap'' defining and prioritizing possible future public interest research and deployment efforts that would improve energy efficiency. Although there are many opinions concerning the energy intensity of data centers and the aggregate effect on California's electrical power systems, there is very little publicly available information. Through this project, actual energy consumption at its end use was measured in a number of data centers. This benchmark data was documented in case study reports, along with site-specific energy efficiency recommendations. Additionally, other data center energy benchmarks were obtained through synergistic projects, prior PG&E studies, and industry contacts. In total, energy benchmarks for sixteen data centers were obtained. For this project, a broad definition of ''data center'' was adopted which included internet hosting, corporate, institutional, governmental, educational and other miscellaneous data centers. Typically these facilities require specialized infrastructure to provide high quality power and cooling for IT equipment. All of these data center types were considered in the development of an estimate of the total power consumption in California. Finally, a research ''roadmap'' was developed

Efficient energy management measures in steel industry for economic utilization

Directory of Open Access Journals (Sweden)

Gurinderbir Singh Grewal

2016-11-01

Full Text Available The application of energy efficient Induction Machines (IM is explained in reference to power consumption savings. In energy efficient IM, losses for various Horse Power (HP ratings are summarized for bringing effective changes in design. Emphasis is laid on how load factor, speed & power quality affect machine’s efficiency. Replacement of conventional IM of higher power rating is done with required energy efficient Doubly Fed Induction Machine (DFIM to enhance the performance at variable speeds near rated power outputs. Results of the proposed approach will give substantial savings in energy & loss reduction. The field data of Jindal Steel Rolling Mill (JSRM at Hisar, Haryana (India is taken into consideration. This paper proposes a non-intrusive air gap torque method for efficiency estimation of in-service IMs. This approach gives results considering stray-load and friction-windage loss according to IEC standard and IEEE112-B standard. The proposed method is validated experimentally whose effectiveness is witnessed using MATLAB/SIMULINK.

Polish Foundation for Energy Efficiency

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-12-31

The Polish Foundation for Energy Efficiency (FEWE) was established in Poland at the end of 1990. FEWE, as an independent and non-profit organization, has the following objectives: to strive towards an energy efficient national economy, and to show the way and methods by use of which energy efficiency can be increased. The activity of the Foundation covers the entire territory of Poland through three regional centers: in Warsaw, Katowice and Cracow. FEWE employs well-known and experienced specialists within thermal and power engineering, civil engineering, economy and applied sciences. The organizer of the Foundation has been Battelle Memorial Institute - Pacific Northwest Laboratories from the USA.

Design of The High Efficiency Power Factor Correction Circuit for Power Supply

Directory of Open Access Journals (Sweden)

Atiye Hülya OBDAN

2017-12-01

Full Text Available Designing power factor correction circuits for switched power supplies has become important in recent years in terms of efficient use of energy. Power factor correction techniques play a significant role in high power density and energy efficiency. For these purposes, bridgeless PFC topologies and control strategies have been developed alongside basic boost PFC circuits. The power density can be increased using bridgeless structures by means of reducing losses in the circuit. This article examines bridgeless PFC structures and compares their performances in terms of losses and power factor. A semi-bridgeless PFC, which is widely used at high power levels, was analyzed and simulated. The designed circuit simulation using the current mode control method was performed in the PSIM program. A prototype of a 900 W semi-bridgeless PFC circuit was implemented and the results obtained from the circuit are presented

Efficiency Analysis of a Wave Power Generation System by Using Multibody Dynamics

International Nuclear Information System (INIS)

Kim, Min Soo; Sohn, Jeong Hyun; Kim, Jung Hee; Sung, Yong Jun

2016-01-01

The energy absorption efficiency of a wave power generation system is calculated as the ratio of the wave power to the power of the system. Because absorption efficiency depends on the dynamic behavior of the wave power generation system, a dynamic analysis of the wave power generation system is required to estimate the energy absorption efficiency of the system. In this study, a dynamic analysis of the wave power generation system under wave loads is performed to estimate the energy absorption efficiency. RecurDyn is employed to carry out the dynamic analysis of the system, and the Morison equation is used for the wave load model. According to the results, the lower the wave height and the shorter the period, the higher is the absorption efficiency of the system

Efficiency Analysis of a Wave Power Generation System by Using Multibody Dynamics

Energy Technology Data Exchange (ETDEWEB)

Kim, Min Soo; Sohn, Jeong Hyun [Pukyong National Univ., Busan (Korea, Republic of); Kim, Jung Hee; Sung, Yong Jun [INGINE Inc., Seoul (Korea, Republic of)

2016-06-15

The energy absorption efficiency of a wave power generation system is calculated as the ratio of the wave power to the power of the system. Because absorption efficiency depends on the dynamic behavior of the wave power generation system, a dynamic analysis of the wave power generation system is required to estimate the energy absorption efficiency of the system. In this study, a dynamic analysis of the wave power generation system under wave loads is performed to estimate the energy absorption efficiency. RecurDyn is employed to carry out the dynamic analysis of the system, and the Morison equation is used for the wave load model. According to the results, the lower the wave height and the shorter the period, the higher is the absorption efficiency of the system.

Novel high efficient speed sensorless controller for maximum power extraction from wind energy conversion systems

International Nuclear Information System (INIS)

Fathabadi, Hassan

2016-01-01

Highlights: • Novel sensorless MPPT technique without drawbacks of other sensor/sensorless methods. • Tracking the actual MPP of WECSs, no tracking the MPP of their wind turbines. • Actually extracting the highest output power from WECSs. • Novel MPPT technique having the MPPT efficiency more than 98.5% for WECSs. • Novel MPPT technique having short convergence time for WECSs. - Abstract: In this study, a novel high accurate sensorless maximum power point tracking (MPPT) method is proposed. The technique tracks the actual maximum power point of a wind energy conversion system (WECS) at which maximum output power is extracted from the system, not the maximum power point of its wind turbine at which maximum mechanical power is obtained from the turbine, so it actually extracts the highest output power from the system. The technique only uses input voltage and current of the converter used in the system, and neither needs any speed sensors (anemometer and tachometer) nor has the drawbacks of other sensor/sensorless based MPPT methods. The technique has been implemented as a MPPT controller by constructing a WECS. Theoretical results, the technique performance, and its advantages are validated by presenting real experimental results. The real static-dynamic response of the MPPT controller is experimentally obtained that verifies the proposed MPPT technique high accurately extracts the highest instant power from wind energy conversion systems with the MPPT efficiency of more than 98.5% and a short convergence time that is only 25 s for the constructed system having a total inertia and friction coefficient of 3.93 kg m 2 and 0.014 N m s, respectively.

Factors which influence Nova Scotia farmers in implementing energy efficiency and renewable energy measures

International Nuclear Information System (INIS)

Bailey, J.A.; Gordon, R.; Burton, D.; Yiridoe, E.K.

2008-01-01

Improvements in energy efficiency and renewable energy use can reduce farm operating costs and reduce greenhouse gas (GHG) emissions. Responses (n=224, representing a 32% response rate) from a mail survey were used to assess use and interest in energy efficient and renewable energy options on farms in Nova Scotia, Canada. Energy efficiency options used the most were behavior, insulation, and lighting. Few farms used renewable energy options. Approximately 78% of farmers indicated an interest in implementing energy efficiency and renewable energy options. Interest varied by farm type and size. Interest increased with farm size. The two main efficiency options of interest were lighting (60.8%) and insulation (43.7%), while wind power development (55.5%) and solar water heating (24.5%) were the main renewable options of interest. Farmers concerned about power and equipment reliability were less likely to be interested in implementing options. Farmers concerned about the environment were more likely to be interested in implementing options. Current use of certain energy efficiency technologies, such as efficient lighting, influenced implementation interest

Establishing strategic energy assessment indicators for Zimbabwe: A key to improving electrical energy efficiency

Science.gov (United States)

Goto, Felix

In Zimbabwe, there is still very little realization of the potential of demand side management (DSM) to increase industrial energy efficiency. Without clear guidelines that indicate the most economic energy efficiency strategies to implement, it is difficult for industry to easily evaluate the benefits of energy assessments. This research focused on establishing and evaluating indicators that guide correct implementation of energy assessments into Zimbabwean industry. This quantitative and qualitative study used a theoretic approach to develop indicators that identified industrial subsectors that should be targeted for DSM interventions. This may bring about reduction in energy demand in high power consuming Zimbabwean industrial companies, which were compared with energy utility performances of similar industrial companies in countries located in other parts of the world. This research used pattern-matching, categorical aggregation, and stochastic frontier regression analysis for data analysis. In maximizing electrical efficiency, the implications of this study may be used by individual companies in Zimbabwe to perform energy efficiency self-diagnoses, operational efficiency evaluations, and capital resource justifications. From a societal perspective, this study may benefit Zimbabwe because it provides opportunities for the alleviation of both shortages in power supply and the capital constraints of building new generating capacity. This study will also benefit ordinary Zimbabweans by lowering energy costs and providing reliable power. This promotes sustainable economic growth and lowers the need for foreign currency to import power.

Energy - efficient buildings in pakistan

International Nuclear Information System (INIS)

Sohail, M.; Qureshi, M.U.D.

2011-01-01

Pakistan is one of the countries with the highest energy consumption for domestic use. Annual energy consumption by the domestic sector is 45.9 % of the total, while the industrial sector, consumes about 27.5%. About half of the total energy consumed is used in buildings and/or heating, ventilation and air-conditioning (HVAC) and lighting appliances. The energy consumed for the same purposes in China and UK is 25 to 30 % and 40 %, respectively, even in extreme weather conditions. Energy deficiency in Pakistan is approximately 5,000 MWe, which results in worst load-shedding in summers and, lately, even in winters. Building new energy sources like dams, coal power plants and renewable energy power projects are some possible solutions, but these are time taking and need at least 2 to 6 years to complete, depending upon the nature of the project. Fast development of energy-efficient buildings is, therefore, necessary to deal with exacerbating energy-crisis and related environmental impact in Pakistan. Innovations in the prevailing building-design will help the country in reducing the energy burden. These innovations may include improved architectural designs, energy-efficient building materials, electrical appliances and implementation of building energy-efficiency codes. In 1987, the National Energy Conservation Centre (ENERCON), was established under Ministry of Environment, Government of Pakistan, with the aim to build awareness among the masses for energy conservation, and to make policies regarding energy-conservation structures in the country. But no policy regarding building energy codes has been introduced by ENERCON till now. In collaboration with Pakistan Engineering Council (PEC), ENERCON has recently finalized the Building Energy Code of Pakistan Energy Provisions 2011 for which statutory notification is under process for necessary amendment in the building by-laws. The implementation of this Energy Code will result in 25 to 30 % of energy savings in the

Coordination of Energy Efficiency and Demand Response

Energy Technology Data Exchange (ETDEWEB)

Goldman, Charles; Reid, Michael; Levy, Roger; Silverstein, Alison

2010-01-29

This paper reviews the relationship between energy efficiency and demand response and discusses approaches and barriers to coordinating energy efficiency and demand response. The paper is intended to support the 10 implementation goals of the National Action Plan for Energy Efficiency's Vision to achieve all cost-effective energy efficiency by 2025. Improving energy efficiency in our homes, businesses, schools, governments, and industries - which consume more than 70 percent of the nation's natural gas and electricity - is one of the most constructive, cost-effective ways to address the challenges of high energy prices, energy security and independence, air pollution, and global climate change. While energy efficiency is an increasingly prominent component of efforts to supply affordable, reliable, secure, and clean electric power, demand response is becoming a valuable tool in utility and regional resource plans. The Federal Energy Regulatory Commission (FERC) estimated the contribution from existing U.S. demand response resources at about 41,000 megawatts (MW), about 5.8 percent of 2008 summer peak demand (FERC, 2008). Moreover, FERC recently estimated nationwide achievable demand response potential at 138,000 MW (14 percent of peak demand) by 2019 (FERC, 2009).2 A recent Electric Power Research Institute study estimates that 'the combination of demand response and energy efficiency programs has the potential to reduce non-coincident summer peak demand by 157 GW' by 2030, or 14-20 percent below projected levels (EPRI, 2009a). This paper supports the Action Plan's effort to coordinate energy efficiency and demand response programs to maximize value to customers. For information on the full suite of policy and programmatic options for removing barriers to energy efficiency, see the Vision for 2025 and the various other Action Plan papers and guides available at www.epa.gov/eeactionplan.

Power Electronics and Control of Renewable Energy Systems

DEFF Research Database (Denmark)

Iov, Florin; Ciobotaru, Mihai; Sera, Dezso

2007-01-01

sources from the conventional, fossil (and short term) based energy sources to renewable energy resources. Another is to use high efficient power electronics in power generation, power transmission/distribution and end-user application. This paper discuss some of the most emerging renewable energy sources......The global electrical energy consumption is still rising and there is a demand to double the power capacity within 20 years. The production, distribution and use of energy should be as technological efficient as possible and incentives to save energy at the end-user should also be set up....... Deregulation of energy has in the past lowered the investment in larger power plants, which means the need for new electrical power sources may be very high in the near future. Two major technologies will play important roles to solve the future problems. One is to change the electrical power production...

High-power density miniscale power generation and energy harvesting systems

International Nuclear Information System (INIS)

Lyshevski, Sergey Edward

2011-01-01

This paper reports design, analysis, evaluations and characterization of miniscale self-sustained power generation systems. Our ultimate objective is to guarantee highly-efficient mechanical-to-electrical energy conversion, ensure premier wind- or hydro-energy harvesting capabilities, enable electric machinery and power electronics solutions, stabilize output voltage, etc. By performing the advanced scalable power generation system design, we enable miniscale energy sources and energy harvesting technologies. The proposed systems integrate: (1) turbine which rotates a radial- or axial-topology permanent-magnet synchronous generator at variable angular velocity depending on flow rate, speed and load, and, (2) power electronic module with controllable rectifier, soft-switching converter and energy storage stages. These scalable energy systems can be utilized as miniscale auxiliary and self-sustained power units in various applications, such as, aerospace, automotive, biotechnology, biomedical, and marine. The proposed systems uniquely suit various submersible and harsh environment applications. Due to operation in dynamic rapidly-changing envelopes (variable speed, load changes, etc.), sound solutions are researched, proposed and verified. We focus on enabling system organizations utilizing advanced developments for various components, such as generators, converters, and energy storage. Basic, applied and experimental findings are reported. The prototypes of integrated power generation systems were tested, characterized and evaluated. It is documented that high-power density, high efficiency, robustness and other enabling capabilities are achieved. The results and solutions are scalable from micro (∼100 μW) to medium (∼100 kW) and heavy-duty (sub-megawatt) auxiliary and power systems.

Energy-Efficiency in Optical Networks

DEFF Research Database (Denmark)

Saldaña Cercos, Silvia

This thesis expands the state-of-the-art on the complex problem of implementing energy efficient optical networks. The main contribution of this Ph.D. thesis is providing a holistic approach in a multi-layered manner where different tools are used to tackle the urgent need of both estimating...... and optimizing power consumption in different network segments. An energy consumption analysis for a novel digital signal processing for signal slicing to reduce bandwidth requirements for passive optical networks is presented in this thesis. This scheme aims at re-using low bandwidth equipment to cope...... with parallel optics and WDM systems is reported. These results show the trade-off between increased capacity and both power consumption and system performance. In conclusion, an energy-efficient set of tools has been provided covering different aspects of the telecommunication network resulting in a cohesive...

Recycled Thermal Energy from High Power Light Emitting Diode Light Source.

Science.gov (United States)

Ji, Jae-Hoon; Jo, GaeHun; Ha, Jae-Geun; Koo, Sang-Mo; Kamiko, Masao; Hong, JunHee; Koh, Jung-Hyuk

2018-09-01

In this research, the recycled electrical energy from wasted thermal energy in high power Light Emitting Diode (LED) system will be investigated. The luminous efficiency of lights has been improved in recent years by employing the high power LED system, therefore energy efficiency was improved compared with that of typical lighting sources. To increase energy efficiency of high power LED system further, wasted thermal energy should be re-considered. Therefore, wasted thermal energy was collected and re-used them as electrical energy. The increased electrical efficiency of high power LED devices was accomplished by considering the recycled heat energy, which is wasted thermal energy from the LED. In this work, increased electrical efficiency will be considered and investigated by employing the high power LED system, which has high thermal loss during the operating time. For this research, well designed thermoelement with heat radiation system was employed to enhance the collecting thermal energy from the LED system, and then convert it as recycled electrical energy.

An energy-efficient, adiabatic electrode stimulator with inductive energy recycling and feedback current regulation.

Science.gov (United States)

Arfin, Scott K; Sarpeshkar, Rahul

2012-02-01

In this paper, we present a novel energy-efficient electrode stimulator. Our stimulator uses inductive storage and recycling of energy in a dynamic power supply. This supply drives an electrode in an adiabatic fashion such that energy consumption is minimized. It also utilizes a shunt current-sensor to monitor and regulate the current through the electrode via feedback, thus enabling flexible and safe stimulation. Since there are no explicit current sources or current limiters, wasteful energy dissipation across such elements is naturally avoided. The dynamic power supply allows efficient transfer of energy both to and from the electrode and is based on a DC-DC converter topology that we use in a bidirectional fashion in forward-buck or reverse-boost modes. In an exemplary electrode implementation intended for neural stimulation, we show how the stimulator combines the efficiency of voltage control and the safety and accuracy of current control in a single low-power integrated-circuit built in a standard .35 μm CMOS process. This stimulator achieves a 2x-3x reduction in energy consumption as compared to a conventional current-source-based stimulator operating from a fixed power supply. We perform a theoretical analysis of the energy efficiency that is in accord with experimental measurements. This theoretical analysis reveals that further improvements in energy efficiency may be achievable with better implementations in the future. Our electrode stimulator could be widely useful for neural, cardiac, retinal, cochlear, muscular and other biomedical implants where low power operation is important.

Energy efficiency

International Nuclear Information System (INIS)

Marvillet, Ch.; Tochon, P.; Mercier, P.

2004-01-01

World energy demand is constantly rising. This is a legitimate trend, insofar as access to energy enables enhanced quality of life and sanitation levels for populations. On the other hand, such increased consumption generates effects that may be catastrophic for the future of the planet (climate change, environmental imbalance), should this growth conform to the patterns followed, up to recent times, by most industrialized countries. Reduction of greenhouse gas emissions, development of new energy sources and energy efficiency are seen as the major challenges to be taken up for the world of tomorrow. In France, the National Energy Debate indeed emphasized, in 2003, the requirement to control both demand for, and offer of, energy, through a strategic orientation law for energy. The French position corresponds to a slightly singular situation - and a privileged one, compared to other countries - owing to massive use of nuclear power for electricity generation. This option allows France to be responsible for a mere 2% of worldwide greenhouse gas emissions. Real advances can nonetheless still be achieved as regards improved energy efficiency, particularly in the transportation and residential-tertiary sectors, following the lead, in this respect, shown by industry. These two sectors indeed account for over half of the country CO 2 emissions (26% and 25% respectively). With respect to transportation, the work carried out by CEA on the hydrogen pathway, energy converters, and electricity storage has been covered by the preceding chapters. As regards housing, a topic addressed by one of the papers in this chapter, investigations at CEA concern integration of the various devices enabling value-added use of renewable energies. At the same time, the organization is carrying through its activity in the extensive area of heat exchangers, allowing industry to benefit from improved understanding in the modeling of flows. An activity evidenced by advances in energy efficiency for

Power Analysis of Energy Efficient DES Algorithm and Implementation on 28nm FPGA

DEFF Research Database (Denmark)

Thind, Vandana; Pandey, Bishwajeet; Hussain, Dil muhammed Akbar

2016-01-01

In this work, we have done power analysis ofData Encryption Standard (DES) algorithm using Xilinx ISE software development kit. We have analyzed the amount of power utilized by selective components on board i.e., FPGA Artix-7, where DES algorithm is implemented. The components taken into consider......In this work, we have done power analysis ofData Encryption Standard (DES) algorithm using Xilinx ISE software development kit. We have analyzed the amount of power utilized by selective components on board i.e., FPGA Artix-7, where DES algorithm is implemented. The components taken...... into consideration areclock power, logic power, signals power, IOs power, leakage powerand supply power (dynamic and quiescent). We have used four different WLAN frequencies (2.4 GHz, 3.6 GHz, 4.9GHz, and 5.9 GHz) and four different IO standards like HSTL-I, HSTL-II, HSTL-II-18, HSTL-I-18 for power analysis. We have...... achieved13-47% saving in power at different frequencies and withdifferent energy efficient HSTL IO standard. We calculated the percentage change in the IO power with respect to the mean values of IO power at four different frequencies. We notified that there is minimum of -37.5% and maximum of +35...

Efficiency of Energy Harvesting in Ni-Mn-Ga Shape Memory Alloys

Science.gov (United States)

Lindquist, Paul; Hobza, Tony; Patrick, Charles; Müllner, Peter

2018-03-01

Many researchers have reported on the voltage and power generated while energy harvesting using Ni-Mn-Ga shape memory alloys; few researchers report on the power conversion efficiency of energy harvesting. We measured the magneto-mechanical behavior and energy harvesting of Ni-Mn-Ga shape memory alloys to quantify the efficiency of energy harvesting using the inverse magneto-plastic effect. At low frequencies, less than 150 Hz, the power conversion efficiency is less than 0.1%. Power conversion efficiency increases with (i) increasing actuation frequency, (ii) increasing actuation stroke, and (iii) decreasing twinning stress. Extrapolating the results of low-frequency experiments to the kHz actuation regime yields a power conversion factor of about 20% for 3 kHz actuation frequency, 7% actuation strain, and 0.05 MPa twinning stress.

Measuring energy efficiency: Is energy intensity a good evidence base?

International Nuclear Information System (INIS)

Proskuryakova, L.; Kovalev, A.

2015-01-01

Highlights: • Energy intensity measure reflects consumption, not energy efficiency. • Thermodynamic indicators should describe energy efficiency at all levels. • These indicators should have no reference to economic or financial parameters. • A set of energy efficiency indicators should satisfy several basic principles. • There are trade-offs between energy efficiency, power and costs. - Abstract: There is a widespread assumption in energy statistics and econometrics that energy intensity and energy efficiency are equivalent measures of energy performance of economies. The paper points to the discrepancy between the engineering concept of energy efficiency and the energy intensity as it is understood in macroeconomic statistics. This double discrepancy concerns definitions (while engineering concept of energy efficiency is based on the thermodynamic definition, energy intensity includes economic measures) and use. With regard to the latter, the authors conclude that energy intensity can only provide indirect and delayed evidence of technological and engineering energy efficiency of energy conversion processes, which entails shortcomings for management and policymaking. Therefore, we suggest to stop considering subsectoral, sectoral and other levels of energy intensities as aggregates of lower-level energy efficiency. It is suggested that the insufficiency of energy intensity indicators can be compensated with the introduction of thermodynamic indicators describing energy efficiency at the physical, technological, enterprise, sub-sector, sectoral and national levels without references to any economic or financial parameters. Structured statistical data on thermodynamic efficiency is offered as a better option for identifying break-through technologies and technological bottle-necks that constrain efficiency advancements. It is also suggested that macro-level thermodynamic indicators should be based on the thermodynamic first law efficiency and the energy

Power electronics - key technology for renewable energy systems

DEFF Research Database (Denmark)

Blaabjerg, Frede; Iov, Florin; Kerekes, Tamas

2011-01-01

sources to renewable energy sources. Another is to use high efficient power electronics in power generation, power transmission/distribution and end-user application. This paper discuss trends of the most emerging renewable energy sources, wind energy and photovoltaics, which by means of power electronics...... as efficient as possible. Further, the emerging climate changes is arguing to find sustainable future solutions. Of many options, two major technologies will play important roles to solve parts of those future problems. One is to change the electrical power production from conventional, fossil based energy......The electrical energy consumption continues to grow and more applications are based on electricity. We can expect that more 60% of all energy consumption will be converted and used as electricity. Therefore, it is a demand that production, distribution and use of electrical energy are done...

Energy efficiency of electrical infrared heating elements

International Nuclear Information System (INIS)

Brown, K.J.; Farrelly, R.; O’Shaughnessy, S.M.; Robinson, A.J.

2016-01-01

Highlights: • Characterization of the radiant energy efficiency of infrared heating elements. • Performed for a commercially available ceramic heater element for two cases. • Total radiant power and net radiant efficiency is computed. • Radiant efficiencies are strongly dependant on the input power to the element. • In-plane efficiencies depend on the distance from the heater. - Abstract: A measurement system has been designed to characterize the radiant energy efficiency of infrared heating elements. The system also allows for measurement of the radiant heat flux distribution emitted from radiant heater assemblies. To facilitate these, a 6-axis robotic arm is fitted with a Schmidt–Boelter radiant heat flux gauge. A LabVIEW interface operates the robot and positions the sensor in the desired location and subsequently acquires the desired radiant heat flux measurement. To illustrate the functionality of the measurement system and methodology, radiant heat flux distributions and efficiency calculations are performed for a commercially available ceramic heater element for two cases. In the first, a spherical surface is traced around the entire heater assembly and the total radiant power and net radiant efficiency is computed. In the second, 50 cm × 50 cm vertical planes are traced parallel to the front face of the heater assembly at distances between 10 cm and 50 cm and the in-plane power and efficiencies are computed. The results indicate that the radiant efficiencies are strongly dependant on the input power to the element and, for the in-plane efficiencies, depend on the distance from the heater.

Two novel techniques for increasing energy efficiency of photovoltaic-battery systems

International Nuclear Information System (INIS)

Fathabadi, Hassan

2015-01-01

Highlights: • Two novel techniques for increasing the energy efficiency of PV-battery systems. • Practically, 27% increase in the energy efficiency of PV-battery systems. • Novel proposed DC/PWM inverter for substituting conventional primary DC/DC converters. • Presenting theoretical, simulation & experimental results to verify the above claims. - Abstract: A photovoltaic (PV)-battery power source consists of a PV panel, a primary DC/DC converter, and a battery or a batteries bank. It is generally used to provide electric energy for local consumers such as buildings. Maximum power point tracking (MPPT) schemes cannot be applied to it because the PV panel output current is only determined by the state of charge (SOC) of the battery. In this study, two novel techniques are proposed to increase the energy efficiency of PV-battery power sources. Replacing the primary DC/DC converter with a novel proposed DC/PWM inverter, and decomposing the PV panel into a set of parallel homogenous configured PV modules are the two proposed techniques. It is shown that the implementation of each technique effectively increases the energy efficiency of PV-battery power sources. The two techniques are combined to each other to implement a new PV-battery power source. It is proved that the energy efficiency of the new version is significantly more than conventional version. Simulated results performed in MATLAB/Proteus 6 verify an increase of 29% in the energy efficiency. Four PV-battery power sources have been built, and comparative experimental results are presented that verify an increase of 27% in the energy efficiency.

Efficient Use of Energy: as a Life Style

Directory of Open Access Journals (Sweden)

Omneya Sabry

2017-06-01

Full Text Available Since the Early Eighties of the last Century, the Egyptian Government considered Energy Conservation as one of the main pillars of Energy Planning in Egypt, based on the fact that investing in Energy Efficiency is more cost effective than in constructing new Power Plants.Energy Efficiency (EE Programs financed by International Financing Institutions focused at that time, on Energy Audits in Industrial Buildings, Power Plants, Electricity Transmission and in some other Governmental Buildings. Recommendations for Efficient Use of Energy and reducing energy consumption at those entities were implemented by the Use of Efficient Lamps, Improving Power Factor, Waste Heat Recovery, Thermal Insulation, Efficient Firing in Boilers…. Consequently, High Quality Energy Efficient Products were competing in the market with others not having the same advantage.Although the above mentioned EE Programs included Awareness Campaigns for all sectors but the consumption in Residential Sector remained high and increased more and more ,exceeding even the consumption in Industrial Sector specially that the prices of electricity were highly subsidized.For that reason, more awareness campaigns (Lectures, Brochures, Audio and visual advertisement and more incentives were offered by Ministry of Electricity and Renewable Energy (MoERE to consumers in the Residential Sector. Meanwhile, a Program to reduce gradually subsidies on electricity prices started aiming to push consumers to follow energy efficiency instructions and buy efficient appliances especially while they were suffering from electricity cut for about two years.To prepare for Market Transformation to efficient appliances the Government, issued the Standard Specifications and Labeling for Energy Efficient Appliances (lamps, refrigerators, freezers, washing machines, air conditioners, dish washers and others. Meanwhile, these Standards are supported with Accredited Testing Labs in National Entities (NREA

High-power density miniscale power generation and energy harvesting systems

Energy Technology Data Exchange (ETDEWEB)

Lyshevski, Sergey Edward [Department of Electrical and Microelectronics Engineering, Rochester Institute of Technology, Rochester, NY 14623-5603 (United States)

2011-01-15

This paper reports design, analysis, evaluations and characterization of miniscale self-sustained power generation systems. Our ultimate objective is to guarantee highly-efficient mechanical-to-electrical energy conversion, ensure premier wind- or hydro-energy harvesting capabilities, enable electric machinery and power electronics solutions, stabilize output voltage, etc. By performing the advanced scalable power generation system design, we enable miniscale energy sources and energy harvesting technologies. The proposed systems integrate: (1) turbine which rotates a radial- or axial-topology permanent-magnet synchronous generator at variable angular velocity depending on flow rate, speed and load, and, (2) power electronic module with controllable rectifier, soft-switching converter and energy storage stages. These scalable energy systems can be utilized as miniscale auxiliary and self-sustained power units in various applications, such as, aerospace, automotive, biotechnology, biomedical, and marine. The proposed systems uniquely suit various submersible and harsh environment applications. Due to operation in dynamic rapidly-changing envelopes (variable speed, load changes, etc.), sound solutions are researched, proposed and verified. We focus on enabling system organizations utilizing advanced developments for various components, such as generators, converters, and energy storage. Basic, applied and experimental findings are reported. The prototypes of integrated power generation systems were tested, characterized and evaluated. It is documented that high-power density, high efficiency, robustness and other enabling capabilities are achieved. The results and solutions are scalable from micro ({proportional_to}100 {mu}W) to medium ({proportional_to}100 kW) and heavy-duty (sub-megawatt) auxiliary and power systems. (author)

The relation between energy efficiency and general objectives

International Nuclear Information System (INIS)

Holmberg, John; Naessen, Jonas; Sprei, Frances

2006-09-01

Three overall objectives for energy efficiency programs are discussed: Reduction of negative externalities, esp. climatic change; Phase-out of nuclear power while limiting electricity imports; and creating welfare gains by correcting market failures of energy efficiency programs (rebound effects)

Energy efficiency in the world and Turkey and investigation of energy efficiency in Turkish Industry

International Nuclear Information System (INIS)

Kavak, K.

2005-09-01

The reserves of fossil fuels which currently respond to the major part of world energy requirements are being running out very fast. Because it is forecasted that reserves of some fossil fuels like oil and natural gas will come to an end in the second half of this century, exploiting all energy resources in an efficient manner has great importance. Throughout the world where the energy demand grows continuously but the resources decrease gradually, many types of programs are implemented to provide efficient energy use. In Turkey, although there have been some efforts in last two decades, the importance of the issue could not be undersood yet. Turkey'sgeneral energy policy still focuses on supply security and finding ways to meet the growing demand, rather than decreasing the demand by energy efficiency. In this study, the possible opportunities and benefits that Turkey would gain by energy efficiency is pointed out. The studies about energy efficiency which have been conducted in the world and Turkey are examined. The measurement that can be taken in the sectors such as industry, power plants, buildings, transportation and the utilities of these measures for energy economy are indicated. The successful practices of energy efficiency studies in various countries, the state of some countries which pioneer efficiency implementations. Turkey's situation in energy in the light of basic indicators such as energy consumption per capita and enrgy intensity, the energy efficiency studies that have been done and should be done in various sectors of Turkey are also discussed in this thesis. Turkish industry's energy comsumption is analyzed as a seperate chapter by taking into consideration energy efficiency, energy intensity and energy resources. The general energy consumption and energy intensity tendencies of main manufacturing industries between 1995 and 2002 are explored and resource utilization ratios are investigated. This chapter provides to find out what kind of

Microbial battery for efficient energy recovery.

Science.gov (United States)

Xie, Xing; Ye, Meng; Hsu, Po-Chun; Liu, Nian; Criddle, Craig S; Cui, Yi

2013-10-01

By harnessing the oxidative power of microorganisms, energy can be recovered from reservoirs of less-concentrated organic matter, such as marine sediment, wastewater, and waste biomass. Left unmanaged, these reservoirs can become eutrophic dead zones and sites of greenhouse gas generation. Here, we introduce a unique means of energy recovery from these reservoirs-a microbial battery (MB) consisting of an anode colonized by microorganisms and a reoxidizable solid-state cathode. The MB has a single-chamber configuration and does not contain ion-exchange membranes. Bench-scale MB prototypes were constructed from commercially available materials using glucose or domestic wastewater as electron donor and silver oxide as a coupled solid-state oxidant electrode. The MB achieved an efficiency of electrical energy conversion of 49% based on the combustion enthalpy of the organic matter consumed or 44% based on the organic matter added. Electrochemical reoxidation of the solid-state electrode decreased net efficiency to about 30%. This net efficiency of energy recovery (unoptimized) is comparable to methane fermentation with combined heat and power.

Municipalities and energy efficiency in countries in transition

International Nuclear Information System (INIS)

Rezessy, Silvia; Dimitrov, Konstantin; Urge-Vorsatz, Diana; Baruch, Seth

2006-01-01

It is widely recognized that many cost-efficient opportunities to employ end-use energy efficiency measures exist in countries in transition (CITs) and that municipal authorities have an essential role to play in capturing these opportunities. The aim of this paper is to review the factors that determine the degree of involvement of local authorities in the market for energy services and energy efficient (EE) equipment in three CITs: Bulgaria, Hungary and the Former Yugoslav Republic of Macedonia (hereafter: Macedonia). We achieve this aim by examining the current status of local governments as the most powerful determinant of municipal market involvement. Two broad groups of factors are discussed: statutory obligations and powers of local governments, especially energy-related tasks, and finance. We explain how specific features within these two areas may influence the motivation of local authorities to improve energy efficiency and their capacity to do so. We argue that greater decentralization is the first step in augmenting the role of local authorities in the market for energy services and EE equipment. Based on the analysis we give recommendations on how to encourage municipal authorities to use market mechanisms more extensively to deliver energy efficiency

Energy-efficient relay selection and optimal power allocation for performance-constrained dual-hop variable-gain AF relaying

KAUST Repository

Zafar, Ammar; Radaydeh, Redha Mahmoud Mesleh; Chen, Yunfei; Alouini, Mohamed-Slim

2013-01-01

This paper investigates the energy-efficiency enhancement of a variable-gain dual-hop amplify-and-forward (AF) relay network utilizing selective relaying. The objective is to minimize the total consumed power while keeping the end-to-end signal

The PurdueTracer: An Energy-Efficient Human-Powered Hydraulic Bicycle with Flexible Operation and Software Aids

Directory of Open Access Journals (Sweden)

Gianluca Marinaro

2018-01-01

Full Text Available Hydrostatic transmissions (HT are widely applied to heavy-duty mobile applications because of the advantages of layout flexibility, power to weight ratio, and ease of control. Though applications of fluid power in light-duty vehicles face challenges, including the unavailability of off-the-shelf components suitable to the power scale, there are potential advantages for HTs in human-powered vehicles, such as bicycles, the most important one being the energy-saving advantage achievable through regenerative braking in a hybrid HT. This paper describes an innovative design for a hydraulic hybrid bicycle, i.e., the PurdueTracer. The PurdueTracer is an energy-efficient human-powered hydraulic bicycle with flexible operation and software aids. An open-circuit hydraulic hybrid transmission allows PurdueTracer to operate in four modes: Pedaling, Charging, Boost, and Regeneration, to satisfy users’ need for different riding occasions. An aluminum chassis that also functions as a system reservoir was customized for the PurdueTracer to optimize the durability, riding comfort, and space for components. The selection of the hydraulic components was performed by creating a model of the bicycle in AMESim simulation software and conducting a numerical optimization based on the model. The electronic system equipped users with informative feedback showing the bicycle performance, intuitive execution of functions, and comprehensive guidance for operation. This paper describes the design approach and the main results of the PurdueTracer, which also won the 2017 National Fluid Power Association Fluid Power Vehicle Challenge. This championship serves to prove the excellence of this vehicle in terms of effectiveness, efficiency, durability, and novelty.

Energy efficiency system development

Science.gov (United States)

Leman, A. M.; Rahman, K. A.; Chong, Haw Jie; Salleh, Mohd Najib Mohd; Yusof, M. Z. M.

2017-09-01

By subjecting to the massive usage of electrical energy in Malaysia, energy efficiency is now one of the key areas of focus in climate change mitigation. This paper focuses on the development of an energy efficiency system of household electrical appliances for residential areas. Distribution of Questionnaires and pay a visit to few selected residential areas are conducted during the fulfilment of the project as well as some advice on how to save energy are shared with the participants. Based on the collected data, the system developed by the UTHM Energy Team is then evaluated from the aspect of the consumers' behaviour in using electrical appliances and the potential reduction targeted by the team. By the end of the project, 60% of the participants had successfully reduced the electrical power consumption set by the UTHM Energy Team. The reasons for whether the success and the failure is further analysed in this project.

Evaluation on the Efficiency of Biomass Power Generation Industry in China

Directory of Open Access Journals (Sweden)

Jingqi Sun

2014-01-01

Full Text Available As a developing country with large population, China is facing the problems of energy resource shortage and growing environmental pollution arising from the coal-dominated energy structure. Biomass energy, as a kind of renewable energy with the characteristics of being easy to store and friendly to environment, has become the focus of China’s energy development in the future. Affected by the advanced power generation technology and diversified geography environment, the biomass power generation projects show new features in recent years. Hence, it is necessary to evaluate the efficiency of biomass power generation industry by employing proper method with the consideration of new features. In this paper, the regional difference as a new feature of biomass power generation industry is taken into consideration, and the AR model is employed to modify the zero-weight issue when using data envelopment analysis (DEA method to evaluate the efficiency of biomass power generation industry. 30 biomass power generation enterprises in China are selected as the sample, and the efficiency evaluation is performed. The result can provide some insights into the sustainable development of biomass power generation industry in China.

Analysis of Energy Efficiency in Dynamic Optical Networks Employing Solar Energy Sources

DEFF Research Database (Denmark)

Wang, Jiayuan; Fagertun, Anna Manolova; Ruepp, Sarah Renée

2013-01-01

The paper presents energy efficient routing in dynamic optical networks, where solar energy sources are employed for the network nodes. Different parameters are evaluated, including the number of nodes that have access to solar energy sources, the different maximum solar output power, traffic type...... and the locations of solar powered nodes. Results show a maximum 39% savings in energy consumption with different increases in connection blocking probability....

Increasing the efficiency of thermal power stations

International Nuclear Information System (INIS)

Schwarz, N.F.

1984-01-01

High energy prices and an increased investment of costs in power plants as well as the necessity to minimize all kinds of environmental pollution have severe consequences on the construction and operation of thermal power stations. One of the most promising measures to cope with the mentioned problems is to raise the thermal efficiency of power plants. With the example of an Austrian electric utility it can be shown that by application of high efficiency combined cycles primary energy can be converted into electricity in a most efficient manner. Excellent operating experience has proved the high reliability of these relatively complex systems. Raising the temperature of the gas topping process still higher will not raise the efficiency considerably. In this respect a Rankine cycle is superior to a Brayton cycle. In a temperature range of 850 to 900 0 C were conventional materials with known properties can still be used, only the alkali metals cesium and potassium have the necessary physical and thermodynamic properties for application in Rankine topping cycles. Building on experience gained in the Fast Breeder development and from the US space program, a potassium topping cycle linked to a conventional water steam cycle with an intermediate diphenyl vapour cycle has been proposed which should give thermal efficiencies in excess of 50%. In a multi-national program this so called Treble Rankine Cycle is being investigated under the auspices of the International Energy Agency. Work is in progress to investigate the technical and economic feasibility of this energy conversion system. Experimental investigations are already under way in the Austrian Research Center Seibersdorf where high temperature liquid metal test facilities have been operated since 1968. (Author)

Energy efficient cross layer design for spectrum sharing systems

KAUST Repository

Alabbasi, AbdulRahman; Shihada, Basem

2016-01-01

We propose a cross layer design that optimizes the energy efficiency of spectrum sharing systems. The energy per good bit (EPG) is considered as an energy efficiency metric. We optimize the secondary user's transmission power and media access frame

Promoting energy efficiency in developing countries: The role of NGOs

International Nuclear Information System (INIS)

Wojtaszek, E.I.

1993-06-01

Developing countries need energy growth to spur economic growth. Yet energy activities contribute significantly to local water pollution and global greenhouse gas emissions. Energy efficiency offers the means to achieve the twin goals of sustainable economic/social development and environmental protection. Energy efficiency increases industrial competitiveness and frees up capital so it can be applied to other uses, such as health and education. The key to improving energy efficiency in developing countries will be acquiring and applying Western technologies, practices, and policies and building national institutions for promoting energy efficiency. Relevant energy-efficient technologies include the use of better electric motors, adjustable speed controls, combined cycle power cogeneration, improved lighting, better refrigeration technologies, and improved electric power transmission and distribution systems. Western countries can best help developing countries by providing guidance and resources to support nongovernmental organizations (NGOS) staffed by local experts; these institutions can capture the energy efficiency potential and ensure environmental protection in developing countries

Generating power at high efficiency combined cycle technology for sustainable energy production

CERN Document Server

Jeffs, E

2008-01-01

Combined cycle technology is used to generate power at one of the highest levels of efficiency of conventional power plants. It does this through primary generation from a gas turbine coupled with secondary generation from a steam turbine powered by primary exhaust heat. Generating power at high efficiency thoroughly charts the development and implementation of this technology in power plants and looks to the future of the technology, noting the advantages of the most important technical features - including gas turbines, steam generator, combined heat and power and integrated gasification com

Energy intensities, EROIs (energy returned on invested), and energy payback times of electricity generating power plants

International Nuclear Information System (INIS)

Weißbach, D.; Ruprecht, G.; Huke, A.; Czerski, K.; Gottlieb, S.; Hussein, A.

2013-01-01

The energy returned on invested, EROI, has been evaluated for typical power plants representing wind energy, photovoltaics, solar thermal, hydro, natural gas, biogas, coal and nuclear power. The strict exergy concept with no “primary energy weighting”, updated material databases, and updated technical procedures make it possible to directly compare the overall efficiency of those power plants on a uniform mathematical and physical basis. Pump storage systems, needed for solar and wind energy, have been included in the EROI so that the efficiency can be compared with an “unbuffered” scenario. The results show that nuclear, hydro, coal, and natural gas power systems (in this order) are one order of magnitude more effective than photovoltaics and wind power. - Highlights: ► Nuclear, “renewable” and fossil energy are comparable on a uniform physical basis. ► Energy storage is considered for the calculation, reducing the ERoEI remarkably. ► All power systems generate more energy than they consume. ► Photovoltaics, biomass and wind (buffered) are below the economical threshold

New York Power Authority`s energy-efficient refigerator program for the New York City Housing Authority - savings evaluation

Energy Technology Data Exchange (ETDEWEB)

Pratt, R.G.; Miller, J.D.

1997-09-01

The New York Power Authority (NYPA) and the New York City Housing Authority (NYCHA) are replacing refrigerators in New York City public housing with new, highly energy-efficient models over a five-year period. This report describes the analysis of the energy cost savings achieved through the replacement of 20,000 refrigerators in 1996, the first year of the NYPA/NYCHA program. The NYPA/NYCHA project serves as the lynchpin of a larger program designed to offer energy-efficient appliances to housing authorities across the country. The national program is a partnership between the U.S. Department of Energy (DOE) and the Consortium for Energy Efficiency (CEE). Starting with the 1997 refrigerator contract, this program invites other housing authorities to join NYPA in its volume purchase of energy-efficient refrigerators, at the same price and terms available to NYPA. Through these volume purchases, DOE`s ENERGY STAR{reg_sign} Partnerships program hopes to encourage appliance manufacturers to bring more efficient appliances to the market and to provide volume purchasers with the per-unit price savings of a bulk purchaser. DOE asked the Pacific Northwest National Laboratory (PNNL) to establish a protocol for evaluating the savings achieved with the NYPA refrigerators. That protocol is summarized in this report.

Space solar power - An energy alternative

Science.gov (United States)

Johnson, R. W.

1978-01-01

The space solar power concept is concerned with the use of a Space Power Satellite (SPS) which orbits the earth at geostationary altitude. Two large symmetrical solar collectors convert solar energy directly to electricity using photovoltaic cells woven into blankets. The dc electricity is directed to microwave generators incorporated in a transmitting antenna located between the solar collectors. The antenna directs the microwave beam to a receiving antenna on earth where the microwave energy is efficiently converted back to dc electricity. The SPS design promises 30-year and beyond lifetimes. The SPS is relatively pollution free as it promises earth-equivalence of 80-85% efficient ground-based thermal power plant.

Towards Energy Efficient Cognitive Radio Systems

KAUST Repository

Alabbasi, AbdulRahman

2016-07-14

Cognitive radio (CR) is a cutting-edge wireless communication technology that adopts several existing communication concepts in order to efficiently utilize the spectrum and meet the users demands of high throughput and real-time systems. Conventionally, high throughput demands are met through adopting broadband and multi-antenna technologies such as, orthogonal frequency division multiplexing (OFDM) and Multi-Input Multi-Output (MIMO). Whereas, real-time application demands are met by analyzing metrics which characterize the delay limited channels, such as, outage probability over block-fading channels. Being an environmental friendly technology, energy efficiency metrics should be considered in the design of a CR application. This thesis tackles the energy efficiency of CR system from different aspects, utilizing different measuring metrics and constrains. Under the single-input single-output (SISO) OFDM we minimized the energy per goodbit (EPG) metric subject to several power and Quality of Service (QoS) constraints. In this approach, the minimum EPG metric is optimized via proposing two optimal and sub-optimal resource allocation schemes. We consider several parameters as optimization variables, such as, power policy, sensing threshold, and channel quality threshold. We also captured the impact of involving the media access control (MAC) layers parameters, such as, frame length, in the minimization of a modified EPG metric. Also, a MAC protocol, i.e., hybrid automatic repeat request (HARQ), and the associated power consumption of the retransmission mechanism is considered in the formulation of the problem. In this context, the optimal power and frame length are derived to minimize the modified EPG while considering several spectrum-sharing scenarios, which depend on sensing information. In MIMO based CR system, we maximized capacity to power ratio (CPR) (as an energy efficiency (EE) metric) subject to several power and QoS constraints. In this context, the

Strengthening power generation efficiency utilizing liquefied natural gas cold energy by a novel two-stage condensation Rankine cycle (TCRC) system

International Nuclear Information System (INIS)

Bao, Junjiang; Lin, Yan; Zhang, Ruixiang; Zhang, Ning; He, Gaohong

2017-01-01

Highlights: • A two-stage condensation Rankine cycle (TCRC) system is proposed. • Net power output and thermal efficiency increases by 45.27% and 42.91%. • The effects of the condensation temperatures are analyzed. • 14 working fluids (such as propane, butane etc.) are compared. - Abstract: For the low efficiency of the traditional power generation system with liquefied natural gas (LNG) cold energy utilization, by improving the heat transfer characteristic between the working fluid and LNG, this paper has proposed a two-stage condensation Rankine cycle (TCRC) system. Using propane as working fluid, compared with the combined cycle in the conventional LNG cold energy power generation method, the net power output, thermal efficiency and exergy efficiency of the TCRC system are respectively increased by 45.27%, 42.91% and 52.31%. Meanwhile, the effects of the first-stage and second-stage condensation temperature and LNG vaporization pressure on the performance and cost index of the TCRC system (net power output, thermal efficiency, exergy efficiency and UA) are analyzed. Finally, using the net power output as the objective function, with 14 organic fluids (such as propane, butane etc.) as working fluids, the first-stage and second-stage condensation temperature at different LNG vaporization pressures are optimized. The results show that there exists a first-stage and second-stage condensation temperature making the performance of the TCRC system optimal. When LNG vaporization pressure is supercritical pressure, R116 has the best economy among all the investigated working fluids, and while R150 and R23 are better when the vaporization pressure of LNG is subcritical.

Rolling resistance and propulsion efficiency of manual and power-assisted wheelchairs.

Science.gov (United States)

Pavlidou, Efthymia; Kloosterman, Marieke G M; Buurke, Jaap H; Rietman, Johan S; Janssen, Thomas W J

2015-11-01

Rolling resistance is one of the main forces resisting wheelchair propulsion and thus affecting stress exerted on the upper limbs. The present study investigates the differences in rolling resistance, propulsion efficiency and energy expenditure required by the user during power-assisted and manual propulsion. Different tire pressures (50%, 75%, 100%) and two different levels of motor assistance were tested. Drag force, energy expenditure and propulsion efficiency were measured in 10 able-bodied individuals under different experimental settings on a treadmill. Results showed that drag force levels were significantly higher in the 50%, compared to the 75% and 100% inflation conditions. In terms of wheelchair type, the manual wheelchair displayed significantly lower drag force values than the power-assisted one. The use of extra-power-assisted wheelchair appeared to be significantly superior to conventional power-assisted and manual wheelchairs concerning both propulsion efficiency and energy expenditure required by the user. Overall, the results of the study suggest that the use of power-assisted wheelchair was more efficient and required less energy input by the user, depending on the motor assistance provided. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

Incentive mechanisms to promote energy efficiency programs in power distribution companies

International Nuclear Information System (INIS)

Osorio, Karim; Sauma, Enzo

2015-01-01

Power distribution companies (DISCOs) play an important role in promoting energy efficiency (hereafter EE), mainly due to the fact that they have detailed information regarding their clients' consumption patterns. However, under the traditional regulatory framework, DISCOs have disincentives to promote EE, due to the fact that a reduction in sales also means a reduction in their revenues and profits. Most regulatory policies encouraging EE have some embedded payment schemes that allow financing EE programs. In this paper, we focus on these EE-programs' payment schemes that are embedded into the regulatory policies. Specifically, this paper studies two models of the Principal–Agent bi-level type in order to analyze the economic effects of implementing different payment schemes to foster EE in DISCOs. The main difference between each model is that uncertainty in energy savings is considered by the electricity regulatory institution in only one of the models. In terms of the results, it is observed that, in general terms, it is more convenient for the regulator to adopt a performance-based incentive mechanism than a payment scheme financing only the fixed costs of implementing EE programs. However, if the electricity regulatory institution seeks a higher level of minimum expected utility, it is optimal to adopt a mixed system of compensation, which takes into account the fixed cost compensation and performance-based incentive payments. - Highlights: • We studied different payment schemes to promote energy efficiency in DISCOs. • We propose two bi-level models based on the Principal–Agent theory. • Uncertainty associated with energy savings is incorporated in one of the models. • A performance-based payment scheme is generally more convenient for the regulator. • A mixed payment scheme is optimal when a lower level of uncertainty is tolerated

Energy efficient scheme for cognitive radios utilizing soft sensing

KAUST Repository

Alabbasi, AbdulRahman; Rezki, Zouheir; Shihada, Basem

2014-01-01

In this paper we propose an energy efficient cognitive radio system. Our design considers an underlaying resource allocation combined with soft sensing information to achieve a sub-optimum energy efficient system. The sub-optimality is achieved by optimizing over a channel inversion power policy instead of considering a water-filling power policy. We consider an Energy per Goodbit (EPG) metric to express the energy efficient objective function of the system and as an evaluation metric to our system performance. Since our optimization problem is not a known convex problem, we prove its convexity to guarantee its feasibility. We evaluate the proposed scheme comparing to a benchmark system through both analytical and numerical results.

Energy efficient scheme for cognitive radios utilizing soft sensing

KAUST Repository

Alabbasi, Abdulrahman

2014-04-06

In this paper we propose an energy efficient cognitive radio system. Our design considers an underlaying resource allocation combined with soft sensing information to achieve a sub-optimum energy efficient system. The sub-optimality is achieved by optimizing over a channel inversion power policy instead of considering a water-filling power policy. We consider an Energy per Goodbit (EPG) metric to express the energy efficient objective function of the system and as an evaluation metric to our system performance. Since our optimization problem is not a known convex problem, we prove its convexity to guarantee its feasibility. We evaluate the proposed scheme comparing to a benchmark system through both analytical and numerical results.

Energy Efficiency in Self Organising Networks

DEFF Research Database (Denmark)

Kisielius, Edvinas; Popovska Avramova, Andrijana; Zakrzewska, Anna

2013-01-01

We evaluate the performance of an energy efficient algorithm that controls power emissions and the number of powered cell sites (eNBs) in overlaid Long Term Evolution (LTE) networks. Simulations are carried out in OPNET Modeler and we investigate cells cites designed to meet peak hours trac demand...

High-efficiency integrated piezoelectric energy harvesting systems

Science.gov (United States)

Hande, Abhiman; Shah, Pradeep

2010-04-01

This paper describes hierarchically architectured development of an energy harvesting (EH) system that consists of micro and/or macro-scale harvesters matched to multiple components of remote wireless sensor and communication nodes. The micro-scale harvesters consist of thin-film MEMS piezoelectric cantilever arrays and power generation modules in IC-like form to allow efficient EH from vibrations. The design uses new high conversion efficiency thin-film processes combined with novel cantilever structures tuned to multiple resonant frequencies as broadband arrays. The macro-scale harvesters are used to power the collector nodes that have higher power specifications. These bulk harvesters can be integrated with efficient adaptive power management circuits that match transducer impedance and maximize power harvested from multiple scavenging sources with very low intrinsic power consumption. Texas MicroPower, Inc. is developing process based on a composition that has the highest reported energy density as compared to other commercially available bulk PZT-based sensor/actuator ceramic materials and extending it to thin-film materials and miniature conversion transducer structures. The multiform factor harvesters can be deployed for several military and commercial applications such as underground unattended sensors, sensors in oil rigs, structural health monitoring, supply chain management, and battlefield applications such as sensors on soldier apparel, equipment, and wearable electronics.

In Pursuit of Energy Efficiency in India's Agriculture: Fighting 'Free Power' or Working with it?

International Nuclear Information System (INIS)

Swain, Ashwini; Charnoz, Olivier

2012-08-01

While about 70% of Indian electricity is carbon-based, a quarter of the nation's consumption goes into agriculture, to extract groundwater for irrigation. Improving the energy efficiency of Indian agriculture is thus a critical issue for the world at large, from both a climate change and energy security perspective. Yet, the picture is made immensely complex given the entrenched policy of providing 'free power' to farmers since the Green Revolution of the 1970's. Over the past two decades, a neo-liberal discourse shared by many Indian and international technocrats has emerged that frames 'free power' as a unilateral problem that leads to economic inefficiencies affecting utilities, the state governments but also the farmers themselves through the unfair allocation of subsidies. The solution that is hence most advocated is to revise and increase tariffs and to improve the technical efficiency of India's 23 million pumps. Key international donors have promoted this line of thinking, making higher tariffs and universal metering a precondition for financing power-sector reforms. Through qualitative data gathered in interviews and fieldwork in four Indian states (Andhra Pradesh, Maharashtra, Gujarat and West Bengal), this work challenges this perspective. It contends that the raising of electricity prices would deeply and unavoidably aggravate rural poverty as well as endanger food security. Whether one likes it or not, moreover, electricity subsidies have become a cornerstone of rural politics in India, as the Congress Party hegemony was challenged by regional parties with strong support among the peasantry. Both pragmatism and effectiveness now call for looking at 'free power' as a constraint to work with, rather than a problem to work against. At the same time, concentrating solely on technically improving the efficiency of pumps might further aggravate the speed at which water tables are depleted. There is thus a need to first optimise water demand in agriculture

China Energy Group - Sustainable Growth Through EnergyEfficiency

Energy Technology Data Exchange (ETDEWEB)

Levine, Mark; Fridley, David; Lin, Jiang; Sinton, Jonathan; Zhou,Nan; Aden, Nathaniel; Huang, Joe; Price, Lynn; McKane, Aimee T.

2006-03-20

China is fueling its phenomenal economic growth with huge quantities of coal. The environmental consequences reach far beyond its borders--China is second only to the United States in greenhouse gas emissions. Expanding its supply of other energy sources, like nuclear power and imported oil, raises trade and security issues. Soaring electricity demand necessitates the construction of 40-70 GW of new capacity per year, creating sustained financing challenges. While daunting, the challenge of meeting China's energy needs presents a wealth of opportunities, particularly in meeting demand through improved energy efficiency and other clean energy technologies. The China Energy Group at the Lawrence Berkeley National Laboratory (LBNL) is committed to understanding these opportunities, and to exploring their implications for policy and business. We work collaboratively with energy researchers, suppliers, regulators, and consumers in China and elsewhere to: better understand the dynamics of energy use in China. Our Research Focus Encompasses Three Major Areas: Buildings, Industry, and Cross-Cutting Activities. Buildings--working to promote energy-efficient buildings and energy-efficient equipment used in buildings. Current work includes promoting the design and use of minimum energy efficiency standards and energy labeling for appliances, and assisting in the development and implementation of building codes for energy-efficient residential and commercial/public buildings. Past work has included a China Residential Energy Consumption Survey and a study of the health impacts of rural household energy use. Industry--understanding China's industrial sector, responsible for the majority of energy consumption in China. Current work includes benchmarking China's major energy-consuming industries to world best practice, examining energy efficiency trends in China's steel and cement industries, implementing voluntary energy efficiency agreements in various

Combining total energy and energy industrial center concepts to increase utilization efficiency of geothermal energy

Science.gov (United States)

Bayliss, B. P.

1974-01-01

Integrating energy production and energy consumption to produce a total energy system within an energy industrial center which would result in more power production from a given energy source and less pollution of the environment is discussed. Strong governmental support would be required for the crash drilling program necessary to implement these concepts. Cooperation among the federal agencies, power producers, and private industry would be essential in avoiding redundant and fruitless projects, and in exploiting most efficiently our geothermal resources.

Energy efficiency in the foreground

International Nuclear Information System (INIS)

Baettig, I.

2006-01-01

In this interview with Eberhard Jochem, professor at the Centre for Energy Policy and Economics at the Federal Institute of Science and Technology (ETH) in Zurich, Switzerland, several energy-relevant topics are discussed. These include high oil prices, possible power shortages and binding commitments in the climate-protection area. The question is asked, how, in consideration of such general conditions, energy use and energy supply should develop in Switzerland. Options for increasing efficiency or the tapping of new energy sources is discussed, as is Switzerland's increasing energy consumption. The '2000 Watt' concept being worked on at the ETH and the activities needed for its realisation are discussed. The effects of this concept on economical and business development are discussed. The potential of renewable forms of energy and the possibility of building combined gas and steam power stations are looked at. Ways of promoting renewable energy and questions concerning the extent of the state intervention in the energy business are considered

An Energy-Efficient Scheme for Multirelay Cooperative Networks with Energy Harvesting

Directory of Open Access Journals (Sweden)

Dingcheng Yang

2016-01-01

Full Text Available This study investigates an energy-efficient scheme in multirelay cooperative networks with energy harvesting where multiple sessions need to communicate with each other via the relay node. A two-step optimal method is proposed which maximizes the system energy efficiency, while taking into account the receiver circuit energy consumption. Firstly, the optimal power allocation for relay nodes is determined to maximize the system throughput; this is based on directional water-filling algorithm. Secondly, using quantum particle swarm optimization (QPSO, a joint relay node selection and session grouping optimization is proposed. With this algorithm, sessions can be classified into multiple groups that are assisted by the specific relay node with the maximum energy efficiency. This approach leads to a better global optimization in searching ability and efficiency. Simulation results show that the proposed scheme can improve the energy efficiency effectively compared with direct transmission and opportunistic relay-selected cooperative transmission.

Energy Efficiency Upgrades for the Clinic and the Tannery and Wind Energy for Power to the Tannery

Energy Technology Data Exchange (ETDEWEB)

Kakoona, Jane [Native Village of Shishmaref, AK (United States); Fredenberg, Connie [Native Village of Shishmaref, AK (United States)

2017-05-08

Under this grant agreement, the Native Village of Shishmaref (Shishmaref) will complete weatherization retrofits to two community buildings, the Clinic and the Tannery, based on recent energy audits. Located 5 miles from the mainland, 126 miles north of Nome and 100 miles south of Kotzebue, Shishmaref sits on Sarichef Island in the Chukchi Sea. As such, Shishmaref experiences a transitional climate between the frozen Arctic and the continental Interior. Summers can be foggy, with average temperatures ranging from 47 to 54 °F (Fahrenheit); winter temperatures average -12 to 2 °F. With heating fuel costs of almost $7/gallon, the goal of this project is to reduce energy costs at the Clinic and the Tannery by at least 30 to 50% through energy efficiency and weatherization measures and through the installation of a residential-size wind turbine to supplement power for the Tannery building.

USE Efficiency: an innovative educational programme for energy efficiency in buildings

Science.gov (United States)

Papadopoulos, Theofilos A.; Christoforidis, Georgios C.; Papagiannis, Grigoris K.

2017-10-01

Power engineers are expected to play a pivotal role in transforming buildings into smart and energy-efficient structures, which is necessary since buildings are responsible for a considerable amount of the total energy consumption. To fulfil this role, a holistic approach in education is required, tackling subjects traditionally related to other engineering disciplines. In this context, USE Efficiency is an inter-institutional and interdisciplinary educational programme implemented in nine European Universities targeting energy efficiency in buildings. The educational programme effectively links professors, students, engineers and industry experts, creating a unique learning environment. The scope of the paper is to present the methodology and the general framework followed in the USE Efficiency programme. The proposed methodology can be adopted for the design and implementation of educational programmes on energy efficiency and sustainable development in higher education. End-of-course survey results showed positive feedback from the participating students, indicating the success of the programme.

Synthesizing modeling of power generation and power limits in energy systems

International Nuclear Information System (INIS)

Sieniutycz, Stanislaw

2015-01-01

Applying the common mathematical procedure of thermodynamic optimization the paper offers a synthesizing or generalizing modeling of power production in various energy generators, such as thermal, solar and electrochemical engines (fuel cells). Static and dynamical power systems are investigated. Dynamical models take into account the gradual downgrading of a resource, caused by power delivery. Analytical modeling includes conversion efficiencies expressed in terms of driving fluxes. Products of efficiencies and driving fluxes determine the power yield and power maxima. While optimization of static systems requires using of differential calculus and Lagrange multipliers, dynamic optimization involves variational calculus and dynamic programming. In reacting mixtures balances of mass and energy serve to derive power yield in terms of an active part of chemical affinity. Power maximization approach is also applied to fuel cells treated as flow engines driven by heat flux and fluxes of chemical reagents. The results of power maxima provide limiting indicators for thermal, solar and SOFC generators. They are more exact than classical reversible limits of energy transformation. - Highlights: • Systematic evaluation of power limits by optimization. • Common thermodynamic methodology for engine systems. • Original, in-depth study of power maxima. • Inclusion of fuel cells to a class of thermodynamic power systems

Distributed energy systems with wind power and energy storage

Energy Technology Data Exchange (ETDEWEB)

Korpaas, Magnus

2004-07-01

The topic of this thesis is the study of energy storage systems operating with wind power plants. The motivation for applying energy storage in this context is that wind power generation is intermittent and generally difficult to predict, and that good wind energy resources are often found in areas with limited grid capacity. Moreover, energy storage in the form of hydrogen makes it possible to provide clean fuel for transportation. The aim of this work has been to evaluate how local energy storage systems should be designed and operated in order to increase the penetration and value of wind power in the power system. Optimization models and sequential and probabilistic simulation models have been developed for this purpose. Chapter 3 presents a sequential simulation model of a general wind hydrogen energy system. Electrolytic hydrogen is used either as a fuel for transportation or for power generation in a stationary fuel cell. The model is useful for evaluating how hydrogen storage can increase the penetration of wind power in areas with limited or no transmission capacity to the main grid. The simulation model is combined with a cost model in order to study how component sizing and choice of operation strategy influence the performance and economics of the wind-hydrogen system. If the stored hydrogen is not used as a separate product, but merely as electrical energy storage, it should be evaluated against other and more energy efficient storage options such as pumped hydro and redox flow cells. A probabilistic model of a grid-connected wind power plant with a general energy storage unit is presented in chapter 4. The energy storage unit is applied for smoothing wind power fluctuations by providing a firm power output to the grid over a specific period. The method described in the chapter is based on the statistical properties of the wind speed and a general representation of the wind energy conversion system and the energy storage unit. This method allows us to

Mobilising Investment in Energy Efficiency

Energy Technology Data Exchange (ETDEWEB)

NONE

2012-07-01

Taxes, loans and grants, trading schemes and white certificates, public procurement and investment in R&D or infrastructure: known collectively as 'economic instruments', these tools can be powerful means of mobilising the finances needed to achieve policy goals by implementing energy efficiency measures. The role of economic instruments is to kick-start the private financial markets and to motivate private investors to fund EE measures. They should reinforce and promote energy performance regulations. This IEA analysis addresses the fact that, to date, relatively little effort has been directed toward evaluating how well economic instruments work. Using the buildings sector to illustrate how such measures can support energy efficiency, this paper can help policy makers better select and design economic instruments appropriate to their policy objectives and national contexts. This report’s three main aims are to: 1) Examine how economic instruments are currently used in energy efficiency policy; 2) Consider how economic instruments can be more effective and efficient in supporting low-energy buildings; and 3) Assess how economic instruments should be funded, where public outlay is needed. Detailed case studies in this report assess examples of economic instruments for energy efficiency in the buildings sector in Canada (grants), France (tax relief and loans), Germany (loans and grants), Ireland (grants) and Italy (white certificates and tax relief).

[Efficiency of oxidant gas generator cells powered by electric or solar energy].

Science.gov (United States)

Brust Carmona, H; Benitez, A; Zarco, J; Sánchez, E; Mascher, I

1998-02-01

Diseases caused by microbial contaminants in drinking water continue to be a serious problem in countries like Mexico. Chlorination, using chlorine gas or chlorine compounds, is one of the best ways to treat drinking water. However, difficulties in handling chlorine gas and the inefficiency of hypochlorite solution dosing systems--due to sociopolitical, economic, and cultural factors--have reduced the utility of these chlorination procedures, especially in far-flung and inaccessible rural communities. These problems led to the development of appropriate technologies for the disinfection of water by means of the on-site generation of mixed oxidant gases (chlorine and ozone). This system, called MOGGOD, operates through the electrolysis of a common salt solution. Simulated system evaluation using a hydraulic model allowed partial and total costs to be calculated. When powered by electrical energy from the community power grid, the system had an efficiency of 90%, and in 10 hours it was able to generate enough gases to disinfect about 200 m3 of water at a cost of approximately N$8 (US $1.30). When the electrolytic cell was run on energy supplied through a photoelectric cell, the investment costs were higher. A system fed by photovoltaic cells could be justified in isolated communities that lack electricity but have a gravity-fed water distribution system.

HelioTrope: An innovative and efficient prototype for solar power production

Directory of Open Access Journals (Sweden)

Papageorgiou George

2014-01-01

Full Text Available The solar energy alternative could provide us with all the energy we need as it exist in vast quantities all around us. We only should be innovative enough in order to improve the efficiency of our systems in capturing and converting solar energy in usable forms of power. By making a case for the solar energy alternative, we identify areas where efficiency can be improved and thereby Solar Energy can become a competitive energy source. This paper suggests an innovative approach to solar energy power production, which is manifested in a prototype given the name HelioTrope. The Heliotrope Solar Energy Production prototype is tested on its' capabilities to efficiently covert solar energy to generation of electricity and other forms of energy for storage or direct use. HelioTrope involves an innovative Stirling engine design and a parabolic concentrating dish with a sun tracking system implementing a control algorithm to maximize the capturing of solar energy. Further, it utilizes a patent developed by the authors where a mechanism is designed for the transmission of reciprocating motion of variable amplitude into unidirectional circular motion. This is employed in our prototype for converting linear reciprocating motion into circular for electricity production, which gives a significant increase in efficiency and reduces maintenance costs. Preliminary calculations indicate that the Heliotrope approach constitutes a competitive solution to solar power production.

Hybrid centralized-distributed power conditioning system for thermoelectric generator with high energy efficiency

DEFF Research Database (Denmark)

Wu, Hongfei; Sun, Kai; Chen, Min

2013-01-01

the proposed system, which benefits for implementing high MPPT efficiency and high conversion efficiency simultaneously. A hybrid MPPT control strategy is proposed for this HCD power conditioning system. The characteristics, circuit implementation and operation principles of the proposed system are presented......-distributed (HCD) power conditioning system for TEG and its control strategy are proposed in this paper. The HCD power conditioning system is composed by a centralized power conversion stage and multiple distributed power conversion stages. Most of the power is processed by the centralized power conversion stage...

Energy versus economic effectiveness in CHP (combined heat and power) applications: Investigation on the critical role of commodities price, taxation and power grid mix efficiency

International Nuclear Information System (INIS)

Comodi, Gabriele; Rossi, Mosè

2016-01-01

Starting from PES (primary energy saving) and CSR (cost saving ratio) definitions the work pinpoints a “grey area” in which CHP (combined heat and power – cogeneration) units can operate with profit and negative PES. In this case, CHP can be profitably operated with lower efficiency with respect to separate production of electrical and thermal energy. The work defines the R-index as the ratio between the cost of fuel and electricity. The optimal value of R-index for which CHP units operate with both environmental benefit (PES > 0) and economic profitability (CSR > 0) is the reference value of electrical efficiency, η_e_l_-_r_e_f, of separate production (national power grid mix). As a consequence, optimal R-index varies from Country to Country. The work demonstrates that the value of R corresponds to the minimum value of electrical efficiency for which any power generator operates with profit. The paper demonstrates that, with regard to the profitability of cogeneration, the ratio between the cost of commodities is more important than their absolute value so that different taxation of each commodity can be a good leverage for energy policy makers to promote high efficiency cogeneration, even in the absence of an incentive mechanism. The final part of the study presents an analysis on micro-CHP technologies payback times for different European Countries. - Highlights: • Investigation of the grey area where CHP profitably operates also with negative PES. • Study starts from definition of primary energy saving PES and cost saving ratio CSR. • Definition of the R-index as the ratio between the cost of fuel and electricity. • The optimal value of R for which the “grey area” disappears is R = η_e_l_-_r_e_f. • R is also the value of η_e_l for which any electric generator profitably operates.

Energy efficiency estimation of a steam powered LNG tanker using normal operating data

Directory of Open Access Journals (Sweden)

Sinha Rajendra Prasad

2016-01-01

Full Text Available A ship’s energy efficiency performance is generally estimated by conducting special sea trials of few hours under very controlled environmental conditions of calm sea, standard draft and optimum trim. This indicator is then used as the benchmark for future reference of the ship’s Energy Efficiency Performance (EEP. In practice, however, for greater part of operating life the ship operates in conditions which are far removed from original sea trial conditions and therefore comparing energy performance with benchmark performance indicator is not truly valid. In such situations a higher fuel consumption reading from the ship fuel meter may not be a true indicator of poor machinery performance or dirty underwater hull. Most likely, the reasons for higher fuel consumption may lie in factors other than the condition of hull and machinery, such as head wind, current, low load operations or incorrect trim [1]. Thus a better and more accurate approach to determine energy efficiency of the ship attributable only to main machinery and underwater hull condition will be to filter out the influence of all spurious and non-standard operating conditions from the ship’s fuel consumption [2]. The author in this paper identifies parameters of a suitable filter to be used on the daily report data of a typical LNG tanker of 33000 kW shaft power to remove effects of spurious and non-standard ship operations on its fuel consumption. The filtered daily report data has been then used to estimate actual fuel efficiency of the ship and compared with the sea trials benchmark performance. Results obtained using data filter show closer agreement with the benchmark EEP than obtained from the monthly mini trials . The data filtering method proposed in this paper has the advantage of using the actual operational data of the ship and thus saving cost of conducting special sea trials to estimate ship EEP. The agreement between estimated results and special sea trials EEP is

Output power maximization of low-power wind energy conversion systems revisited: Possible control solutions

Energy Technology Data Exchange (ETDEWEB)

Vlad, Ciprian; Munteanu, Iulian; Bratcu, Antoneta Iuliana; Ceanga, Emil [' ' Dunarea de Jos' ' University of Galati, 47, Domneasca, 800008-Galati (Romania)

2010-02-15

This paper discusses the problem of output power maximization for low-power wind energy conversion systems operated in partial load. These systems are generally based on multi-polar permanent-magnet synchronous generators, who exhibit significant efficiency variations over the operating range. Unlike the high-power systems, whose mechanical-to-electrical conversion efficiency is high and practically does not modify the global optimum, the low-power systems global conversion efficiency is affected by the generator behavior and the electrical power optimization is no longer equivalent with the mechanical power optimization. The system efficiency has been analyzed by using both the maxima locus of the mechanical power versus the rotational speed characteristics, and the maxima locus of the electrical power delivered versus the rotational speed characteristics. The experimental investigation has been carried out by using a torque-controlled generator taken from a real-world wind turbine coupled to a physically simulated wind turbine rotor. The experimental results indeed show that the steady-state performance of the conversion system is strongly determined by the generator behavior. Some control solutions aiming at maximizing the energy efficiency are envisaged and thoroughly compared through experimental results. (author)

Output power maximization of low-power wind energy conversion systems revisited: Possible control solutions

International Nuclear Information System (INIS)

Vlad, Ciprian; Munteanu, Iulian; Bratcu, Antoneta Iuliana; Ceanga, Emil

2010-01-01

This paper discusses the problem of output power maximization for low-power wind energy conversion systems operated in partial load. These systems are generally based on multi-polar permanent-magnet synchronous generators, who exhibit significant efficiency variations over the operating range. Unlike the high-power systems, whose mechanical-to-electrical conversion efficiency is high and practically does not modify the global optimum, the low-power systems global conversion efficiency is affected by the generator behavior and the electrical power optimization is no longer equivalent with the mechanical power optimization. The system efficiency has been analyzed by using both the maxima locus of the mechanical power versus the rotational speed characteristics, and the maxima locus of the electrical power delivered versus the rotational speed characteristics. The experimental investigation has been carried out by using a torque-controlled generator taken from a real-world wind turbine coupled to a physically simulated wind turbine rotor. The experimental results indeed show that the steady-state performance of the conversion system is strongly determined by the generator behavior. Some control solutions aiming at maximizing the energy efficiency are envisaged and thoroughly compared through experimental results.

Barriers to Industrial Energy Efficiency - Study (Appendix A), June 2015

Energy Technology Data Exchange (ETDEWEB)

None

2015-06-01

This study examines barriers that impede the adoption of energy efficient technologies and practices in the industrial sector, and identifies successful examples and opportunities to overcome these barriers. Three groups of energy efficiency technologies and measures were examined: industrial end-use energy efficiency, industrial demand response, and industrial combined heat and power. This study also includes the estimated economic benefits from hypothetical Federal energy efficiency matching grants, as directed by the Act.

Barriers to Industrial Energy Efficiency - Report to Congress, June 2015

Energy Technology Data Exchange (ETDEWEB)

None

2015-06-01

This report examines barriers that impede the adoption of energy efficient technologies and practices in the industrial sector, and identifies successful examples and opportunities to overcome these barriers. Three groups of energy efficiency technologies and measures were examined: industrial end-use energy efficiency, industrial demand response, and industrial combined heat and power. This report also includes the estimated economic benefits from hypothetical Federal energy efficiency matching grants, as directed by the Act.

Energy Efficient Smartphones: Minimizing the Energy Consumption of Smartphone GPUs using DVFS Governors

KAUST Repository

Ahmad, Enas M.

2013-05-15

Modern smartphones are being designed with increasing processing power, memory capacity, network communication, and graphics performance. Although all of these features are enriching and expanding the experience of a smartphone user, they are significantly adding an overhead on the limited energy of the battery. This thesis aims at enhancing the energy efficiency of modern smartphones and increasing their battery life by minimizing the energy consumption of smartphones Graphical Processing Unit (GPU). Smartphone operating systems are becoming fully hardware-accelerated, which implies relying on the GPU power for rendering all application graphics. In addition, the GPUs installed in smartphones are becoming more and more powerful by the day. This raises an energy consumption concern. We present a novel implementation of GPU Scaling Governors, a Dynamic Voltage and Frequency Scaling (DVFS) scheme implemented in the Android kernel to dynamically scale the GPU. The scheme includes four main governors: Performance, Powersave, Ondmand, and Conservative. Unlike previous studies which looked into the power efficiency of mobile GPUs only through simulation and power estimations, we have implemented our approach on a real modern smartphone GPU, and acquired actual energy measurements using an external power monitor. Our results show that the energy consumption of smartphones can be reduced up to 15% using the Conservative governor in 2D rendering mode, and up to 9% in 3D rendering mode, with minimal effect on the performance.

Energy efficiency in Serbia national energy efficiency program: Strategy and priorities for the future

Directory of Open Access Journals (Sweden)

Oka Simeon

2006-01-01

Full Text Available Energy system in Serbia, in the whole energy chain, from exploitation of primary energy sources, transformations in electric power plants and district heating plants, energy (electric and heat transmission and distribution to final users, and up to final energy consumption, is faced with a number of irrational and inefficient behavior and processes. In order to fight with such situation National Energy Efficiency Program, financed by the Ministry of Science and Environmental Protection has been founded in 2001. Basic facts about status of energy sector in Serbia, with special emphasis on the energy efficiency and use of renewable energy sources have been given in the review paper published in the issue No. 2, 2006 of this journal. In present paper new strategy and priorities of the National Energy Efficiency Program for the future period from 2006 to 2008, and beyond, is presented. This strategy and priorities are mainly based on the same concept and principles as previous, but new reality and new and more simulative economic and financial environment in energy sector made by the Energy low (accepted by Parliament in 2004 and Strategy of Development of Energy Sector in Republic Serbia up to 2015 (accepted by the Parliament in May 2005, have been taken into account. Also, responsibilities that are formulated in the Energy Community Treaty signed by the South-East European countries, and also coming from documents and directives of the European Community and Kyoto Protocol are included in new strategy. Once again necessity of legislative framework and influence of regulations and standards, as well as of the governmental support, has been pointed out if increased energy efficiency and increased use of renewable energy sources are expected. .

A study on electric bicycle energy efficiency

Directory of Open Access Journals (Sweden)

Ivan EVTIMOV

2015-09-01

Full Text Available The paper presents a construction of an experimental electric bicycle for evaluation of the energy efficiency. The bicycle is equipped with onboard computer which can store the information about motion and energy consumption. The result concerning power, energy consumption, recharging during brake process, etc. are given. Energy consumption for 3 typical city routes is studied.

Measuring economy-wide energy efficiency performance: A parametric frontier approach

International Nuclear Information System (INIS)

Zhou, P.; Ang, B.W.; Zhou, D.Q.

2012-01-01

This paper proposes a parametric frontier approach to estimating economy-wide energy efficiency performance from a production efficiency point of view. It uses the Shephard energy distance function to define an energy efficiency index and adopts the stochastic frontier analysis technique to estimate the index. A case study of measuring the economy-wide energy efficiency performance of a sample of OECD countries using the proposed approach is presented. It is found that the proposed parametric frontier approach has higher discriminating power in energy efficiency performance measurement compared to its nonparametric frontier counterparts.

Energy Efficiency and Importance of Renewable Energy Sources in Latvia

Science.gov (United States)

Skapare, I.; Kreslins, A.

2007-10-01

The main goal of Latvian energy policy is to ensure safe and environmentally friendly long-term energy supply at cost-effective prices, contributing to enhance competitiveness, and to ensure safe energy transit. The Latvian Parliament approved an Energy Efficiency Strategy in 2000. Its objective is to decrease energy consumption per unit of GDP by 25% by 2010. Awareness raising, implementation of standards and economic incentives for self financing are the main instruments to increase energy efficiency, mentioned in the strategy. Latvia, as many other European Union member states, is dependent on the import of primary energy resources. The Latvian Renewable Energy strategy is still under development. The only recent study on RES was developed in the framework of a PHARE program in year 2000: "Renewable energy resource program", where three main objectives for a future RES strategy were proposed: 1. To increase the use of wood waste and low value wood and forest residues. 2. To improve efficiency of combustion technologies and to replace outdated plants. 3. To increase the use of renewables in Combined Heat and Power plants (CHP). Through the Renewable Energy and Energy Efficiency Partnership, partners will develop a set of new shared activities, and coordinate and strengthen existing efforts in this area.

Gross efficiency and energy expenditure in kayak ergometer exercise.

Science.gov (United States)

Gomes, B B; Mourão, L; Massart, A; Figueiredo, P; Vilas-Boas, J P; Santos, A M C; Fernandes, R J

2012-08-01

We purposed to study energy expenditure, power output and gross efficiency during kayak ergometer exercise in 12 elite sprint kayakers. 6 males (age 24.2±4.8 years, height 180.4±4.8 cm, body mass 79.7±8.5 kg) and 6 females (age 24.3±4.5 years, height 164.5±3.9 cm, body mass 65.4±3.5 kg), performed an incremental intermittent protocol on kayak ergometer with VO2 and blood lactate concentration assessment, a non-linear increase between power output and energy expenditure being observed. Paddling power output, energy expenditure and gross efficiency corresponding to VO2max averaged 199.92±50.41 W, 75.27±6.30 ml.kg - 1.min - 1, and 10.10±1.08%. Male kayakers presented higher VO2max, power output and gross efficiency at the VO2max, and lower heart rate and maximal lactate concentration than females, but no differences were found between genders regarding energy expenditure at VO2max. Aerobic and anaerobic components of energy expenditure evidenced a significant contribution of anaerobic energy sources in sprint kayak performance. Results also suggested the dependence of the gross efficiency on the changes in the amount of the aerobic and anaerobic contributions, at heavy and severe intensities. The inter-individual variance of the relationship between energy expenditure and the corresponding paddling power output revealed a relevant tracking for females (FDγ=0.73±0.06), conversely to the male group (FDγ=0.27±0.08), supporting that some male kayakers are more skilled in some paddling intensities than others. © Georg Thieme Verlag KG Stuttgart · New York.

Dynamic bounds for power and efficiency of non-ideal energy converters under nonlinear transfer laws

International Nuclear Information System (INIS)

Sieniutycz, Stanislaw

2009-01-01

We present a thermodynamic approach to simulation and modeling of nonlinear energy converters, in particular radiation engines. Novel results are obtained especially for dynamical engines when the temperature of the propelling medium decreases in time due to a continual decrease of the medium's internal energy caused by the power production. Basic thermodynamic principles determine the converter's efficiency and work limits in terms of the entropy production. The real work is a cumulative effect obtained in a system of a resource fluid, a sequence of engines, and an infinite bath. Nonlinear modeling involves dynamic optimization in which the classical expression for efficiency at maximum power is generalized to endoirreversible machines and nonlinear transfer laws. The primary result is a finite-rate generalization of the classical, reversible work potential (exergy). The generalized work function depends on thermal coordinates and a dissipation index, h, i.e. a Hamiltonian of the minimum entropy production problem. This generalized work function implies stronger bounds on work delivered or supplied than the reversible work potential. The role of the nonlinear analyses and dynamic optimization is shown especially for radiation engines. As an example of the kinetic work limit, generalized exergy of radiation fluid is estimated in terms of finite rates, quantified by the Hamiltonian h

Feasibility study and energy efficiency estimation of geothermal power station based on medium enthalpy water

Directory of Open Access Journals (Sweden)

Borsukiewicz-Gozdur Aleksandra

2007-01-01

Full Text Available In the work presented are the results of investigations regarding the effectiveness of operation of power plant fed by geothermal water with the flow rate of 100, 150, and 200 m3/h and temperatures of 70, 80, and 90 °C, i. e. geothermal water with the parameters available in some towns of West Pomeranian region as well as in Stargard Szczecinski (86.4 °C, Poland. The results of calculations regard the system of geothermal power plant with possibility of utilization of heat for technological purposes. Analyzed are possibilities of application of different working fluids with respect to the most efficient utilization of geothermal energy. .

G20 Clean Energy, and Energy Efficiency Deployment and Policy Progress

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-07-01

G-20 Clean Energy, and Energy Efficiency Deployment and Policy Progress, a report prepared by the International Energy Agency (IEA) in collaboration with the G-20 Clean Energy and Energy Efficiency Working Group, provides an overview of clean energy and energy efficiency technology deployment and summarises support policies in place across G-20 countries. The report highlights that while clean energy technology deployment has made steady progress and energy efficiency improvements have been made, continued reliance on fossil fuels to meet growth in global energy demand presents a significant challenge. Scaling-up the deployment of renewable energy, in addition to improving end-use efficiency, enhancing the efficiency of fossil fuel based power generation, and supporting the widespread deployment of CCS will, therefore, also be crucial aspects of the transition to a cleaner energy future. Because the G-20 group of countries represent close to 80% of energy-related CO2 emissions, by developing and deploying energy efficiency and clean energy technologies, they are presented with a unique opportunity to make collective progress in transitioning the global energy system. IEA Deputy Executive Director Richard Jones emphasised the importance of G-20 efforts, saying, 'The IEA welcomes this important collaboration with the G-20. Enhanced deployment of clean energy technologies and of energy efficiency improvements offers energy security and environmental benefits. It will also enable cost savings over the medium and long term -- an aspect that is particularly relevant at a time of economic uncertainty. We believe that enhanced policy assessment and analysis, building on this initial report, will enable governments to take more cost effective and efficient policy decisions.' This report was issued on the authority of the IEA Executive Director, it does not necessarily represent the views of IEA Member countries or the G20.

G20 Clean Energy, and Energy Efficiency Deployment and Policy Progress

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-07-01

G-20 Clean Energy, and Energy Efficiency Deployment and Policy Progress, a report prepared by the International Energy Agency (IEA) in collaboration with the G-20 Clean Energy and Energy Efficiency Working Group, provides an overview of clean energy and energy efficiency technology deployment and summarises support policies in place across G-20 countries. The report highlights that while clean energy technology deployment has made steady progress and energy efficiency improvements have been made, continued reliance on fossil fuels to meet growth in global energy demand presents a significant challenge. Scaling-up the deployment of renewable energy, in addition to improving end-use efficiency, enhancing the efficiency of fossil fuel based power generation, and supporting the widespread deployment of CCS will, therefore, also be crucial aspects of the transition to a cleaner energy future. Because the G-20 group of countries represent close to 80% of energy-related CO2 emissions, by developing and deploying energy efficiency and clean energy technologies, they are presented with a unique opportunity to make collective progress in transitioning the global energy system. IEA Deputy Executive Director Richard Jones emphasised the importance of G-20 efforts, saying, 'The IEA welcomes this important collaboration with the G-20. Enhanced deployment of clean energy technologies and of energy efficiency improvements offers energy security and environmental benefits. It will also enable cost savings over the medium and long term -- an aspect that is particularly relevant at a time of economic uncertainty. We believe that enhanced policy assessment and analysis, building on this initial report, will enable governments to take more cost effective and efficient policy decisions.' This report was issued on the authority of the IEA Executive Director, it does not necessarily represent the views of IEA Member countries or the G20.

Technology Efficiency Study on Nuclear Power and Coal Power in Guangdong Province Based on DEA

International Nuclear Information System (INIS)

Yinong Li; Dong Wang

2006-01-01

Guangdong Province has taken the lead in embarking on nuclear power development to resolve its dire lack of primary resources. With the deepening of the on-going structural reform in the electric power sector in China, the market competition scheme is putting electricity generation enterprises under severe strain. Consequently, it is incumbent upon the nuclear power producers to steadily upgrade management, enhance technical capabilities, reduce cost and improve efficiency. At present, gradual application of such efficiency evaluation methodology has already commenced in some sectors in China including the electric power industry. The purpose of this paper is to use the Data Envelopment Analysis (DEA), which is a cutting-edge approach in the efficiency evaluation field - to study the technological efficiency between nuclear power and coal power in Guangdong Province. The DEA results demonstrate that, as far as Guangdong Province is concerned, the technological efficiency of nuclear power is higher than that of coal power in terms of Technological Efficiency (TE), Pure Technology Efficiency (PTE) and Scale Efficiency (SE). The reason is that nuclear power technology is advanced with a much higher equipment availability factor. Under the same scale, the generation output of nuclear power is far higher than that of equivalent coal power generation. With the environmental protection and sustainable development requirements taken into full account, nuclear power constitutes a clean, safe and highly-efficient energy form which should be extensively harnessed in Guangdong Province to fuel its future continuing economic growth. (authors)

Ultra-low power sensor for autonomous non-invasive voltage measurement in IoT solutions for energy efficiency

Science.gov (United States)

Villani, Clemente; Balsamo, Domenico; Brunelli, Davide; Benini, Luca

2015-05-01

Monitoring current and voltage waveforms is fundamental to assess the power consumption of a system and to improve its energy efficiency. In this paper we present a smart meter for power consumption which does not need any electrical contact with the load or its conductors, and which can measure both current and voltage. Power metering becomes easier and safer and it is also self-sustainable because an energy harvesting module based on inductive coupling powers the entire device from the output of the current sensor. A low cost 32-bit wireless CPU architecture is used for data filtering and processing, while a wireless transceiver sends data via the IEEE 802.15.4 standard. We describe in detail the innovative contact-less voltage measurement system, which is based on capacitive coupling and on an algorithm that exploits two pre-processing channels. The system self-calibrates to perform precise measurements regardless the cable type. Experimental results demonstrate accuracy in comparison with commercial high-cost instruments, showing negligible deviations.

Impedance Matching Antenna-Integrated High-Efficiency Energy Harvesting Circuit

Science.gov (United States)

Shinki, Yuharu; Shibata, Kyohei; Mansour, Mohamed

2017-01-01

This paper describes the design of a high-efficiency energy harvesting circuit with an integrated antenna. The circuit is composed of series resonance and boost rectifier circuits for converting radio frequency power into boosted direct current (DC) voltage. The measured output DC voltage is 5.67 V for an input of 100 mV at 900 MHz. Antenna input impedance matching is optimized for greater efficiency and miniaturization. The measured efficiency of this antenna-integrated energy harvester is 60% for −4.85 dBm input power and a load resistance equal to 20 kΩ at 905 MHz. PMID:28763043

Impedance Matching Antenna-Integrated High-Efficiency Energy Harvesting Circuit

Directory of Open Access Journals (Sweden)

Yuharu Shinki

2017-08-01

Full Text Available This paper describes the design of a high-efficiency energy harvesting circuit with an integrated antenna. The circuit is composed of series resonance and boost rectifier circuits for converting radio frequency power into boosted direct current (DC voltage. The measured output DC voltage is 5.67 V for an input of 100 mV at 900 MHz. Antenna input impedance matching is optimized for greater efficiency and miniaturization. The measured efficiency of this antenna-integrated energy harvester is 60% for −4.85 dBm input power and a load resistance equal to 20 kΩ at 905 MHz.

Impedance Matching Antenna-Integrated High-Efficiency Energy Harvesting Circuit.

Science.gov (United States)

Shinki, Yuharu; Shibata, Kyohei; Mansour, Mohamed; Kanaya, Haruichi

2017-08-01

This paper describes the design of a high-efficiency energy harvesting circuit with an integrated antenna. The circuit is composed of series resonance and boost rectifier circuits for converting radio frequency power into boosted direct current (DC) voltage. The measured output DC voltage is 5.67 V for an input of 100 mV at 900 MHz. Antenna input impedance matching is optimized for greater efficiency and miniaturization. The measured efficiency of this antenna-integrated energy harvester is 60% for -4.85 dBm input power and a load resistance equal to 20 kΩ at 905 MHz.

Energy and exergy analysis of solar power tower plants

International Nuclear Information System (INIS)

Xu Chao; Wang Zhifeng; Li Xin; Sun Feihu

2011-01-01

Establishing the renewable electricity contribution from solar thermal power systems based on energy analysis alone cannot legitimately be complete unless the exergy concept becomes a part of that analysis. This paper presents a theoretical framework for the energy analysis and exergy analysis of the solar power tower system using molten salt as the heat transfer fluid. Both the energy losses and exergy losses in each component and in the overall system are evaluated to identify the causes and locations of the thermodynamic imperfection. Several design parameters including the direct normal irradiation (DNI), the concentration ratio, and the type of power cycle are also tested to evaluate their effects on the energy and exergy performance. The results show that the maximum exergy loss occurs in the receiver system, followed by the heliostat field system, although main energy loss occurs in the power cycle system. The energy and exergy efficiencies of the receiver and the overall system can be increased by increasing the DNI and the concentration ratio, but that increment in the efficiencies varies with the values of DNI and the concentration ratio. It is also found that the overall energy and exergy efficiencies of the solar tower system can be increased to some extent by integrating advanced power cycles including reheat Rankine cycles and supercritical Rankine cycles. - Highlights: →We presented a theoretical framework for the energy and exergy analysis of the solar tower system. →We tested the effects of several design parameters on the energy and exergy performance. →The maximum exergy loss occurs in the receiver system, followed by the heliostat field system. →Integrating advanced power cycles leads to increases in the overall energy and exergy efficiencies.

EPP Energy Efficiency Calculation and Influencing Factor Analysis: Cases in China

Directory of Open Access Journals (Sweden)

Jingmin Wang

2015-01-01

Full Text Available Efficiency power plant (EPP promotes the use of energy efficiency power plant technology and energy efficient equipment, coupled with its low-input, zero pollution, zero emissions, and other advantages, having an important role in the control of energy consumption and energy saving. In order to carry out scientific EPP investment decisions, the level of energy efficiency is an important basis for investment decisions. This paper introduces total factor energy efficiency (TFEE in energy efficiency calculation of EPP, constructs energy efficiency calculation model considering environmental benefits, and takes the micro and macro cases in China for analysis; the results show that the TFEE of both single energy efficiency project and EPP are at a relatively high level (above 0.7, and there is a huge gap between calculation results considering and without considering the environmental benefit. In order to discuss energy efficiency influencing factors, the paper analyzes generalized technological advances variation feature of China typical provinces implementing EPP based on generalized technological advances decomposition model by Malmquist index, finding that the steady growth of M index in these provinces is derived from the management level of implementation of EPP and the large-scale production capacity of formation and management. We hope the models and conclusions could provide some references on EPP energy efficiency calculation and decision.

Energy efficiency and economic feasibility of CCHP driven by stirling engine

International Nuclear Information System (INIS)

Kong, X.Q.; Wang, R.Z.; Huang, X.H.

2004-01-01

This paper deals with the problem of energy efficiency evaluation and economic feasibility analysis of a small scale trigeneration system for combined cooling, heating and power generation (CCHP) with an available Stirling engine. Trigeneration systems have a large potential of energy saving and economical efficiency. The decisive values for energetic efficiency evaluation of such systems are the primary energy rate and comparative primary energy saving (Δq), while the economic feasibility analysis of such systems relates the avoided cost, the total annual saving and payback period. The investigation calculates and compares the energy saving and economic efficiency of trigeneration system with Stirling engine against contemporary conventional independent cooling, heating and power, showing that a CCHP system saves fuel resources and has the assurance of economic benefits

Proceedings of the Canadian District Energy Association's 9. annual conference and exhibition in association with the Canadian Energy Efficiency Alliance : Create, conserve, connect : District energy and energy efficiency for Canadian communities

International Nuclear Information System (INIS)

2004-01-01

This conference provided an opportunity to demonstrate the latest developments in the supply and delivery of clean and efficient power, heating and cooling, with particular attention to proven energy solutions based on district energy and cogeneration technologies. Opportunities for distributed generation in Canada were presented, along with their associated risks and the impacts they have on business efficiency, communities and the environment. Topics of discussion focused on financing local energy projects, emission reduction implications, developing partnerships, best practices for energy systems, strategies for delivering energy efficiency, and policies that support energy solutions. The latest technological advances in research and development were also reviewed. District energy provides heating and cooling from a central plant to multiple users using piped steam through a series of supply and return pipes. Industrial cogeneration takes advantage of excess thermal capacity and reuses it to generate high-value electric power. Both district energy and cogeneration can save money for users, conserve resources, reduce pollution and offer sustainable energy solutions for the future. The conference featured 32 presentations, all of which were indexed separately for inclusion in this database. tabs., figs

Energy efficiency

International Nuclear Information System (INIS)

2010-01-01

After a speech of the CEA's (Commissariat a l'Energie Atomique) general administrator about energy efficiency as a first rank challenge for the planet and for France, this publications proposes several contributions: a discussion of the efficiency of nuclear energy, an economic analysis of R and D's value in the field of fourth generation fast reactors, discussions about biofuels and the relationship between energy efficiency and economic competitiveness, and a discussion about solar photovoltaic efficiency

Powering a Home with Just 25 Watts of Solar PV. Super-Efficient Appliances Can Enable Expanded Off-Grid Energy Service Using Small Solar Power Systems

Energy Technology Data Exchange (ETDEWEB)

Phadke, Amol A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Jacobson, Arne [Schatz Energy Research Center, Arcata, CA (United States); Park, Won Young [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Lee, Ga Rick [Schatz Energy Research Center, Arcata, CA (United States); Alstone, Peter [Univ. of California, Berkeley, CA (United States); Khare, Amit [Schatz Energy Research Center, Arcata, CA (United States)

2015-04-01

Highly efficient direct current (DC) appliances have the potential to dramatically increase the affordability of off-grid solar power systems used for rural electrification in developing countries by reducing the size of the systems required. For example, the combined power requirement of a highly efficient color TV, four DC light emitting diode (LED) lamps, a mobile phone charger, and a radio is approximately 18 watts and can be supported by a small solar power system (at 27 watts peak, Wp). Price declines and efficiency advances in LED technology are already enabling rapidly increased use of small off-grid lighting systems in Africa and Asia. Similar progress is also possible for larger household-scale solar home systems that power appliances such as lights, TVs, fans, radios, and mobile phones. When super-efficient appliances are used, the total cost of solar home systems and their associated appliances can be reduced by as much as 50%. The results vary according to the appliances used with the system. These findings have critical relevance for efforts to provide modern energy services to the 1.2 billion people worldwide without access to the electrical grid and one billion more with unreliable access. However, policy and market support are needed to realize rapid adoption of super-efficient appliances.

Monitoring tools for energy efficiency in Europe

Energy Technology Data Exchange (ETDEWEB)

NONE

2002-07-01

This document brings together the different definitions of the indicators used in the European Odyssee project on energy efficiency indicators. This project was initiated in 1990. It benefits from the combined support of the SAVE programme of the European Commission, of Ademe and of 15 national Efficiency Agencies within the European network of energy efficiency agencies. The objective of the project is to develop and maintain indicators that enable to review progress in energy efficiency and CO{sub 2} emissions abatement, by sector, end-use, etc.. for each country and the EU as a whole. To reach this objective, all data and indicators are stored in a common database called ODYSSEE that is regularly updated. A common methodology is used to produce comparative energy efficiency indicators from the database. The definitions presented in this document concern: 1) the general points (energy intensity, consumption, savings, efficiency, the unit consumption effect and index, the technological effect or savings, the substitution effect and the behavioural/management effect); 2) the macro-indicators (primary and final energy intensities at constant structure, at purchasing power parities, at reference economic structure); 3) industry (energy intensity of industry/manufacturing, of industry at constant structure and at reference structure, unit consumption of steel, cement etc.., process effect); 4) transports (energy intensity, unit consumption of vehicles, average specific consumption, test specific consumption, unit consumption, specific consumption, behavioural energy savings; 5) households and services (unit consumption, specific consumption, energy intensity of households, appliances); 6) transformations (apparent efficiency of energy sector or transformations, efficiency at constant fuel mix, efficiency of electricity sector). The same work is made for the 'key energy efficiency indicators', for the 'aggregate energy efficiency indicators' for

Sustaining with efficiency the renewable energy sources

International Nuclear Information System (INIS)

Bano, L.; Lorenzoni, A.

2008-01-01

European energy policy requires actions, in favour of a more widespread diffusion of renewable energy sources. Is essential to have an efficient financial support to reduce costs. Are presented an estimated of electric power from renewable energy sources and some criticism. Is proposed a modification of green certificates market based on bilateral tradable agreements [it

Crowdsourced Microfinance for Energy Efficiency in Underserved Communities

Energy Technology Data Exchange (ETDEWEB)

Baird, Donnel [BlocPower LLC, New York, NY (United States); Cox, Morris [BlocPower LLC, New York, NY (United States); Harmarneh, Sarey [BlocPower LLC, New York, NY (United States); Zheng, Chen [BlocPower LLC, New York, NY (United States)

2017-06-21

BlocPower’s mission is to provide access to energy efficiency financing for underserved communities across the United States. This project, “Crowdsourced Microfinance for Energy Efficiency in Underserved Communities,” is an extension of that goal and is grounded in the principles of providing engineering and financing services to those in need. The project is based on the creation of a BlocPower Marketplace as a central hub for connecting shovel-ready green buildings to institutional investors. This ‘connection’ entails using online crowdfunding to aggregate debt and equity capital from institutional investors to connect to customers (building owners) across various financial portfolios. BlocPower Marketplace is intended to bring social, environmental, and financial returns to investors while also decreasing investor risk by loaning out funds for energy installations in individual buildings. In detail, the intended benefits of crowdsourcing are two-sided. Firstly, for building owners, clean energy retrofit installations improve building operations, reduce utility costs, and reduce harmful impacts to their surrounding environment. Secondly, for institutional investors, they gain access to a new market of energy efficiency and are able to provide debt or equity capital with high financial returns. This gives investors the opportunity to create social and environmental impact in communities around the country as well. With this in mind, BlocPower designed the marketplace to specifically answer exploratory research questions with respect to the pricing of energy financing. Institutional investors typically charge high rates on project financing solutions in the energy space, particularly in low and middle-income communities, because of fears that required debt service will not be made. This makes access to energy capital exorbitantly difficult for those that need it the most. Through this project, BlocPower tested investor appetite to determine if

Nanofluidic crystal: a facile, high-efficiency and high-power-density scaling up scheme for energy harvesting based on nanofluidic reverse electrodialysis

International Nuclear Information System (INIS)

Ouyang Wei; Wang Wei; Zhang Haixia; Wu Wengang; Li Zhihong

2013-01-01

The great advances in nanotechnology call for advances in miniaturized power sources for micro/nano-scale systems. Nanofluidic channels have received great attention as promising high-power-density substitutes for ion exchange membranes for use in energy harvesting from ambient ionic concentration gradient, namely reverse electrodialysis. This paper proposes the nanofluidic crystal (NFC), of packed nanoparticles in micro-meter-sized confined space, as a facile, high-efficiency and high-power-density scaling-up scheme for energy harvesting by nanofluidic reverse electrodialysis (NRED). Obtained from the self-assembly of nanoparticles in a micropore, the NFC forms an ion-selective network with enormous nanochannels due to electrical double-layer overlap in the nanoparticle interstices. As a proof-of-concept demonstration, a maximum efficiency of 42.3 ± 1.84%, a maximum power density of 2.82 ± 0.22 W m −2 , and a maximum output power of 1.17 ± 0.09 nW/unit (nearly three orders of magnitude of amplification compared to other NREDs) were achieved in our prototype cell, which was prepared within 30 min. The current NFC-based prototype cell can be parallelized and cascaded to achieve the desired output power and open circuit voltage. This NFC-based scaling-up scheme for energy harvesting based on NRED is promising for the building of self-powered micro/nano-scale systems. (paper)

Series Resonant Power Converter for Contactless Energy Transfer with Improved Efficiency

NARCIS (Netherlands)

Valtchev, S.S.

2008-01-01

The development of more efficient power converters is the most important and challenging task for Power Electronics specialists. In the same time, many currently existing or yet to appear future applications require full mechanical independence between the transmitter and receiver of the electrical

Energy efficiency improvement and environment in China

International Nuclear Information System (INIS)

Rouhier, Stephane

2010-01-01

Massive reliance on polluting sources of energy (coal, traditional biomass and oil) has damaged the environment in China over years. Now, China is the world's first carbon dioxide emitter and air pollution represents between 2 and 7 percent of loss of Gross Domestic Product per year, depending on the studies chosen. In order to reduce the level of pollution, one can either enhance the technology in use or reduce the share of polluting fuels in the energy mix. Indeed, current Chinese technologies are far less efficient than those of developed countries and the energy mix is massively composed of polluting sources of energy. So, they both represent huge potential savings. This article enquires the link between diversification, efficiency in the power sector and the per capita emissions and shows that emissions are negatively correlated to a diversification of the energy mix as well as an improvement of power generating technologies. Hence, it justifies the diversification of the energy mix and technology improvement as viable strategies to tackle pollution

Improving the energy efficiency of mine fan assemblages

International Nuclear Information System (INIS)

De Souza, Euler

2015-01-01

Energy associated with ventilating an underground operation comprises a significant portion of a mine operation's base energy demand and is consequently responsible for a large percentage of the total operating costs. Ventilation systems may account from 25 to 40% of the total energy costs and 40–50% of the energy consumption of a mine operation. Fans are the most important mechanical devices used to ventilate underground mines and the total fan power installed in a single mine operation can easily exceed 10,000 kW. Investigations of a number of mine main fan installations have determined their assemblage to be, in general, very energy inefficient. The author has found that 40–80% of the energy consumed by a main fan is used to overcome the resistance of fan assemblage components. This paper presents how engineering design principles can be applied to improve the performance and efficiency of fan installations, resulting in substantial reductions in power consumption, operating cost and greenhouse gas emissions. A detailed case study is presented to demonstrate that, by designing fan assemblages using proper engineering concepts of fluid physics and industrial ventilation design, main fan systems will operate at efficiencies well above 80–90% (compared to common operating efficiencies of between 20 and 65%), resulting in a drastic reduction in a mine's overall costs and base electrical and energy loads. - Highlights: • Increases in fan assemblage efficiencies with minimum capital investment. • Improved designs for substantial fan power and operating cost savings. • General solutions and tactics for improving existing main fan installations. • Case study presented to demonstrate proper design of fan assemblages.

Energy-Efficient Capacitance-to-Digital Converters for Smart Sensor Applications

KAUST Repository

Alhoshany, Abdulaziz

2017-12-01

One of the key requirements in the design of wireless sensor nodes and miniature biomedical devices is energy efficiency. For a sensor node, which is a sensor and readout circuit, to survive on limited energy sources such as a battery or harvested energy, its energy consumption should be minimized. Capacitive sensors are candidates for use in energy-constrained applications, as they do not consume static power and can be used in a wide range of applications to measure different physical, chemical or biological quantities. However, the energy consumption is dominated by the capacitive interface circuit, i.e. the capacitance-to-digital converter (CDC). Several energy-efficient CDC architectures are introduced in this dissertation to meet the demand for high resolution and energy efficiency in smart capacitive sensors. First, we propose an energy-efficient CDC based on a differential successive-approximation data converter. The proposed differential CDC employs an energy-efficient operational transconductance amplifier (OTA) based on an inverter. A wide capacitance range with fine absolute resolution is implemented in the proposed coarse-fine DAC architecture which saves 89% of silicon area. The proposed CDC achieves an energy efficiency figure-of-merit () of 45.8fJ/step, which is the best reported energy efficiency to date. Second, we propose an energy efficient CDC for high-precision capacitive resolution by using oversampling and noise shaping. The proposed CDC achieves 150 aF absolute resolution and an energy efficiency of 187fJ/conversion-step which outperforms state of the art high-precision differential CDCs. In the third and last part, we propose an in-vitro cancer diagnostic biosensor-CMOS platform for low-power, rapid detection, and low cost. The introduced platform is the first to demonstrate the ability to screen and quantify the spermidine/spermine N1 acetyltransferase (SSAT) enzyme which reveals the presence of early-stage cancer, on the surface of a

Energy efficiency analysis of reconfigured distribution system for practical loads

Directory of Open Access Journals (Sweden)

Pawan Kumar

2016-09-01

Full Text Available In deregulated rate structure, the performance evaluation of distribution system for energy efficiency includes; loss minimization, improved power quality, loadability limit, reliability and availability of supply. Energy efficiency changes with the variation in loading pattern and the load behaviour. Further, the nature of load at each node is not explicitly of any one type rather their characteristics depend upon the node voltages. In most cases, load is assumed to be constant power (real and reactive. In this paper voltage dependent practical loads are represented with composite load model and the energy efficiency performance of distribution system for practical loads is evaluated in different configurations of 33-node system.

Comparative analysis of possibilities for raising the efficiency in thermal power plant by utilisation of waste heat energy

Directory of Open Access Journals (Sweden)

Mijakovski Vladimir

2016-01-01

Full Text Available The possibility to use flue gases waste heat for increasing the efficiency of thermal power plant (TPP explained in this work refers to lignite fired TPP-Bitola in Macedonia (3x233 MW installed electric capacity. Possibility to utilize low-temperature heat energy at the plant’s cold end is also considered in the analysis. Specific fuel consumption is used as an analysis and comparison parameter. Its reduction, compared to the basic power unit ranges between 0.4% and 3.4%. An analysis presenting economic feasibility of the low-temperature heat energy utilization concept for two different refrigerants used in the heat pump is also presented.

The energy-efficiency business - Energy utility strategies; Geschaeftsfeld Energieeffizienz. Strategien von Energieversorgern

Energy Technology Data Exchange (ETDEWEB)

Loebbe, S.

2009-07-01

This article takes a look at the energy-efficiency business and the advantages it offers. The author quotes that energy-efficiency can contribute to making savings in primary energy, minimise the economic impact of global warming, improve reliability of supply and protect the gross national product. The advantages of new products for the efficient use of energy are reviewed and the resulting advantages for power customers are noted. Also, possibilities for the positioning of electricity suppliers in the environmental niche is noted. The partial markets involved and estimates concerning the impact of energy-efficiency measures are reviewed. Climate protection, co-operation with energy agencies, consulting services and public relations aspects are also discussed. The prerequisites for successful marketing by the utilities are examined and new business models are discussed along with the clear strategies needed. The development from an electricity utility to a system-competence partner is reviewed.

Energy Efficiency: Finding Leadership Opportunities

Directory of Open Access Journals (Sweden)

William Rosehart

2014-01-01

buildings, and by issuing an annual “premier’s report card,” making public the progress on province-wide efficiency efforts. For a province that continues to enjoy growth in business and population, updated guidelines around new building codes have been proven to improve energy efficiency. And there remains a significant opportunity for Alberta to improve efficiency in its commercial and industrial sectors, the largest users of energy, by providing government incentives to replace ageing equipment with more efficient technology. Alberta is also well suited for a shift toward more combined heat and power generation plants, which can repurpose generated heat that is otherwise wasted, significantly reducing energy demand and costs. And in a province awash in natural gas, incentives to encourage travel using compressed or liquefied natural gas vehicles could serve to boost energy efficiency in the transportation sector as well. Alberta is fortunate in that it has abundant energy and prosperity, making improved energy efficiency a matter of choice, rather than — as in some jurisdictions — one of urgent necessity. It is, however, a choice that Alberta has enough reasons, and resources, to make. All it requires is the will.

SAGD CO2 mitigation through energy efficiency improvements

International Nuclear Information System (INIS)

Plessis du, D.

2010-01-01

An evaluation of the carbon dioxide (CO 2 ) emissions reductions achieved using energy efficiency measures in steam assisted gravity drainage (SAGD) operations was presented. The efficiency of a typical SAGD operation was analyzed using an indexing tool based on the Carnot cycle efficiency to develop an ideal SAGD heat cycle. The benefits of using an organic Rankine cycle (ORC) technology to convert waste heat to electrical power were also investigated. A CO 2 abatement curve was used to identify the economic benefits and costs of various greenhouse gas (GHG) reductions. The level of recovered energy was determined in relation to energy prices, capital costs, and carbon penalties in order to determine the most efficient means of decreasing energy usage. The study demonstrated that energy efficiency can be improved by up to 20 percent, and water loss reductions of up to 50 percent can be achieved using cost-effective energy efficiency measures. Results of the study can be used to guide government policy and provide industry with practical tools to benchmark performance and improve efficiencies. 4 refs., 1 tab., 10 figs.

Energy efficiency in California laboratory-type facilities

Energy Technology Data Exchange (ETDEWEB)

Mills, E.; Bell, G.; Sartor, D. [and others

1996-07-31

The central aim of this project is to provide knowledge and tools for increasing the energy efficiency and performance of new and existing laboratory-type facilities in California. We approach the task along three avenues: (1) identification of current energy use and savings potential, (2) development of a {ital Design guide for energy- Efficient Research Laboratories}, and (3) development of a research agenda for focused technology development and improving out understanding of the market. Laboratory-type facilities use a considerable amount of energy resources. They are also important to the local and state economy, and energy costs are a factor in the overall competitiveness of industries utilizing laboratory-type facilities. Although the potential for energy savings is considerable, improving energy efficiency in laboratory-type facilities is no easy task, and there are many formidable barriers to improving energy efficiency in these specialized facilities. Insufficient motivation for individual stake holders to invest in improving energy efficiency using existing technologies as well as conducting related R&D is indicative of the ``public goods`` nature of the opportunity to achieve energy savings in this sector. Due to demanding environmental control requirements and specialized processes, laboratory-type facilities epitomize the important intersection between energy demands in the buildings sector and the industrial sector. Moreover, given the high importance and value of the activities conducted in laboratory-type facilities, they represent one of the most powerful contexts in which energy efficiency improvements stand to yield abundant non-energy benefits if properly applied.

Performance and energy efficiency in wireless self-organized networks

Energy Technology Data Exchange (ETDEWEB)

Gao, C.

2009-07-01

Self-organized packet radio networks (ad-hoc networks) and wireless sensor networks have got massive attention recently. One of critical problems in such networks is the energy efficiency, because wireless nodes are usually powered by battery. Energy efficiency design can dramatically increase the survivability and stability of wireless ad-hoc/sensor networks. In this thesis the energy efficiency has been considered at different protocol layers for wireless ad-hoc/sensor networks. The energy consumption of wireless nodes is inspected at the physical layer and MAC layer. At the network layer, some current routing protocols are compared and special attention has been paid to reactive routing protocols. A minimum hop analysis is given and according to the analysis result, a modification of AODV routing is proposed. A variation of transmit power can be also applied to clustering algorithm, which is believed to be able to control the scalability of network. Clustering a network can also improve the energy efficiency. We offer a clustering scheme based on the link state measurement and variation of transmit power of intra-cluster and inter-cluster transmission. Simulation shows that it can achieve both targets. In association with the clustering algorithm, a global synchronization scheme is proposed to increase the efficiency of clustering algorithm. The research attention has been also paid to self-organization for multi-hop cellular networks. A 2-hop 2-slot uplink proposal to infrastructure-based cellular networks. The proposed solution can significantly increase the throughput of uplink communication and reduce the energy consumption of wireless terminals. (orig.)

Wireless Powered Cooperative Communications: Power-Splitting Relaying With Energy Accumulation (Author’s Manuscript)

Science.gov (United States)

2016-03-21

decreasing power usage, while improving the transmission performance. A key concern of the energy harvesting enabled coop- erative relay communication is the...improving transmission performance via an efficient utiliza- tion of harvested power has been widely studied for conven- tional energy harvesting techniques...can be used as energy sources for cooperative nodes. Moreover, it has been illustrated in [6] that wireless -powered cooperative relay communications

Power electronics - The key technology for Renewable Energy Systems

DEFF Research Database (Denmark)

Blaabjerg, Frede; Ma, Ke; Yang, Yongheng

2014-01-01

The energy paradigms in many countries (e.g. Germany and Denmark) have experienced a significant change from fossil-based resources to clean renewables (e.g. wind turbines and photovoltaics) in the past few decades. The scenario of highly penetrated renewables is going to be further enhanced...... - Denmark expects to be 100 % fossil-free by 2050. Consequently, it is required that the production, distribution and use of the energy should be as technologically efficient as possible and incentives to save energy at the end-user should also be strengthened. In order to realize the transition smoothly...... and effectively, energy conversion systems, currently based on power electronics technology, will again play an essential role in this energy paradigm shift. Using highly efficient power electronics in power generation, power transmission/distribution and end-user application, together with advanced control...

A transmission power optimization with a minimum node degree for energy-efficient wireless sensor networks with full-reachability.

Science.gov (United States)

Chen, Yi-Ting; Horng, Mong-Fong; Lo, Chih-Cheng; Chu, Shu-Chuan; Pan, Jeng-Shyang; Liao, Bin-Yih

2013-03-20

Transmission power optimization is the most significant factor in prolonging the lifetime and maintaining the connection quality of wireless sensor networks. Un-optimized transmission power of nodes either interferes with or fails to link neighboring nodes. The optimization of transmission power depends on the expected node degree and node distribution. In this study, an optimization approach to an energy-efficient and full reachability wireless sensor network is proposed. In the proposed approach, an adjustment model of the transmission range with a minimum node degree is proposed that focuses on topology control and optimization of the transmission range according to node degree and node density. The model adjusts the tradeoff between energy efficiency and full reachability to obtain an ideal transmission range. In addition, connectivity and reachability are used as performance indices to evaluate the connection quality of a network. The two indices are compared to demonstrate the practicability of framework through simulation results. Furthermore, the relationship between the indices under the conditions of various node degrees is analyzed to generalize the characteristics of node densities. The research results on the reliability and feasibility of the proposed approach will benefit the future real deployments.

A Transmission Power Optimization with a Minimum Node Degree for Energy-Efficient Wireless Sensor Networks with Full-Reachability

Science.gov (United States)

Chen, Yi-Ting; Horng, Mong-Fong; Lo, Chih-Cheng; Chu, Shu-Chuan; Pan, Jeng-Shyang; Liao, Bin-Yih

2013-01-01

Transmission power optimization is the most significant factor in prolonging the lifetime and maintaining the connection quality of wireless sensor networks. Un-optimized transmission power of nodes either interferes with or fails to link neighboring nodes. The optimization of transmission power depends on the expected node degree and node distribution. In this study, an optimization approach to an energy-efficient and full reachability wireless sensor network is proposed. In the proposed approach, an adjustment model of the transmission range with a minimum node degree is proposed that focuses on topology control and optimization of the transmission range according to node degree and node density. The model adjusts the tradeoff between energy efficiency and full reachability to obtain an ideal transmission range. In addition, connectivity and reachability are used as performance indices to evaluate the connection quality of a network. The two indices are compared to demonstrate the practicability of framework through simulation results. Furthermore, the relationship between the indices under the conditions of various node degrees is analyzed to generalize the characteristics of node densities. The research results on the reliability and feasibility of the proposed approach will benefit the future real deployments. PMID:23519351

Efficient electrochemical CO2 conversion powered by renewable energy.

Science.gov (United States)

Kauffman, Douglas R; Thakkar, Jay; Siva, Rajan; Matranga, Christopher; Ohodnicki, Paul R; Zeng, Chenjie; Jin, Rongchao

2015-07-22

The catalytic conversion of CO2 into industrially relevant chemicals is one strategy for mitigating greenhouse gas emissions. Along these lines, electrochemical CO2 conversion technologies are attractive because they can operate with high reaction rates at ambient conditions. However, electrochemical systems require electricity, and CO2 conversion processes must integrate with carbon-free, renewable-energy sources to be viable on larger scales. We utilize Au25 nanoclusters as renewably powered CO2 conversion electrocatalysts with CO2 → CO reaction rates between 400 and 800 L of CO2 per gram of catalytic metal per hour and product selectivities between 80 and 95%. These performance metrics correspond to conversion rates approaching 0.8-1.6 kg of CO2 per gram of catalytic metal per hour. We also present data showing CO2 conversion rates and product selectivity strongly depend on catalyst loading. Optimized systems demonstrate stable operation and reaction turnover numbers (TONs) approaching 6 × 10(6) molCO2 molcatalyst(-1) during a multiday (36 h total hours) CO2 electrolysis experiment containing multiple start/stop cycles. TONs between 1 × 10(6) and 4 × 10(6) molCO2 molcatalyst(-1) were obtained when our system was powered by consumer-grade renewable-energy sources. Daytime photovoltaic-powered CO2 conversion was demonstrated for 12 h and we mimicked low-light or nighttime operation for 24 h with a solar-rechargeable battery. This proof-of-principle study provides some of the initial performance data necessary for assessing the scalability and technical viability of electrochemical CO2 conversion technologies. Specifically, we show the following: (1) all electrochemical CO2 conversion systems will produce a net increase in CO2 emissions if they do not integrate with renewable-energy sources, (2) catalyst loading vs activity trends can be used to tune process rates and product distributions, and (3) state-of-the-art renewable-energy technologies are sufficient

Mechanical energy expenditures and movement efficiency in full body reaching movements.

Science.gov (United States)

Sha, Daohang; France, Christopher R; Thomas, James S

2010-02-01

The effect of target location, speed, and handedness on the average total mechanical energy and movement efficiency is studied in 15 healthy subjects (7 males and 8 females with age 22.9 +/- 1.79 years old) performing full body reaching movements. The average total mechanical energy is measured as the time average of integration of joint power, potential energy, and kinetic energy respectively. Movement efficiency is calculated as the ratio of total kinetic energy to the total joint power and potential energy. Results show that speed and target location have significant effects on total mechanical energy and movement efficiency, but reaching hand only effects kinetic energy. From our findings we conclude that (1) efficiency in whole body reaching is dependent on whether the height of the body center of mass is raised or lowered during the task; (2) efficiency is increased as movement speed is increased, in part because of greater changes in potential energy; and (3) the CNS does not appear to use movement efficiency as a primary planning variable in full body reaching. It may be dependent on a combination of other factors or constraints.

Energy Efficient Design for Two-Way AF Relay Networks

Directory of Open Access Journals (Sweden)

Yong Li

2014-01-01

Full Text Available Conventional designs on two-way relay networks mainly focus on the spectral efficiency (SE rather than energy efficiency (EE. In this paper, we consider a system where two source nodes communicate with each other via an amplify-and-forward (AF relay node and study the power allocation schemes to maximize EE while ensuring a certain data rate. We propose an optimal energy-efficient power allocation algorithm based on iterative search technique. In addition, a closed-form suboptimal solution is derived with reduced complexity and negligible performance degradation. Numerical results show that the proposed schemes can achieve considerable EE improvement compared with conventional designs.

Energy Efficiency of Low-Temperature Deaeration of Makeup Water for a District Heating System

Energy Technology Data Exchange (ETDEWEB)

Sharapov, V. I., E-mail: vlad-sharapov2008@yandex.ru; Kudryavtseva, E. V. [Ulyanovsk State Technical University (Russian Federation)

2016-07-15

It is shown that the temperature of makeup water in district heating systems has a strong effect on the energy efficiency of turbines of thermal power plants. A low-temperature deaeration process that considerably improves the energy efficiency of thermal power plants is developed. The desorbing agent is the gas supplied to the burners of the boiler. The energy efficiency of the process for a typical unit of thermal power plant is assessed.

Center for Efficiency in Sustainable Energy Systems

Energy Technology Data Exchange (ETDEWEB)

Abraham, Martin [Youngstown State Univ., OH (United States)

2016-01-31

The main goal of the Center for Efficiency in Sustainable Energy Systems is to produce a methodology that evaluates a variety of energy systems. Task I. Improved Energy Efficiency for Industrial Processes: This task, completed in partnership with area manufacturers, analyzes the operation of complex manufacturing facilities to provide flexibilities that allow them to improve active-mode power efficiency, lower standby-mode power consumption, and use low cost energy resources to control energy costs in meeting their economic incentives; (2) Identify devices for the efficient transformation of instantaneous or continuous power to different devices and sections of industrial plants; and (3) use these manufacturing sites to demonstrate and validate general principles of power management. Task II. Analysis of a solid oxide fuel cell operating on landfill gas: This task consists of: (1) analysis of a typical landfill gas; (2) establishment of a comprehensive design of the fuel cell system (including the SOFC stack and BOP), including durability analysis; (3) development of suitable reforming methods and catalysts that are tailored to the specific SOFC system concept; and (4) SOFC stack fabrication with testing to demonstrate the salient operational characteristics of the stack, including an analysis of the overall energy conversion efficiency of the system. Task III. Demonstration of an urban wind turbine system: This task consists of (1) design and construction of two side-by-side wind turbine systems on the YSU campus, integrated through power control systems with grid power; (2) preliminary testing of aerodynamic control effectors (provided by a small business partner) to demonstrate improved power control, and evaluation of the system performance, including economic estimates of viability in an urban environment; and (3) computational analysis of the wind turbine system as an enabling activity for development of smart rotor blades that contain integrated sensor

Evaluation of efficiency in Japan electric power companies

International Nuclear Information System (INIS)

Ghaderi, F.; Muyajima, M.

2001-01-01

Achieving energy efficiency also must consider supply efficiency, how much energy it takes to generate electricity and transmit it to the end user. system efficiency reflects the loss of energy during the processes of generation, transmission and distribution of electricity. Of the millions of tons of coal that are burned to produce heat in generation of electricity every year, only one third is converted into electricity.The electric power plant immediately uses 5 to 10 percent of that energy for use in the plant. Around another 10 percent of this energy is consumed in the transmission and distribution of electric energy to end users. Overall,more that 70 percent of the energy used to produce and deliver electricity never gets to the end user. The costs of this wasted energy are reflected in the customer's electricity bill. Furthermore, once delivered, users of electricity are subjected to more h idden c osts the demand charge which reflects the rate at which consumers draw energy from the power plant during a particular time of day, are also affected by the time of year. This additional charge c n be dramatic. For example, the cost for using electric air conditioning at the w rong t ime of the day , are also affected by the time of year. This additional charge can be dramatic. For example, the cost for using electric air conditioning at the wrong time of the day could be as much as 25 to 40 percent higher than what a facility normally pays for electricity during off-peak times. Minimizing the costs of operations, therefor, is a must for all electric companies. In the other hand utility rates, such as the cost of electricity, are a necessary element of operating in all enterprises.In some industries the payment over electricity make a large percentage of their total expenses, but that doesn't mean that every effort should not be made to reduce their impact on the bottom line, it should be considered that a very small change in operating procedure can change

Energy management for cost reduction in the production. TEEM - Total Energy Efficiency Management; Energiemanagement zur Kostensenkung in der Produktion. TEEM - Total Energy Efficiency Management

Energy Technology Data Exchange (ETDEWEB)

Westkaemper, Engelbert; Verl, Alexander (eds.)

2009-07-01

Within the workshop of the Fraunhofer Institute for Manufacturing Engineering and Automation IPA (Stuttgart, Federal Republic of Germany) at 6th October, 2009, in Stuttgart the following lectures were held: (1) Presentation of Fraunhofer Institute for Manufacturing Engineering and Automation IPA (Engelbert Westkaemper); (2) TEEM - Total Energy Efficiency Management - ''With energy management to an energy efficient production'' (Alexander Schloske); (3) DIN EN 16001 Introduction of an energy management system - utilization and advantages for companies (Sylvia Wahren); (4) Analysis of the energy efficiency with power flow - Support and implementation at factory planning and optimization of production (Klaus Erlach); (5) Total Energy Efficiency Management - Approaches at the company Kaercher in injection moulding for example (Axel Leschtar); (6) Modelling the embodied product energy (Shahin Rahimifard); (7) Acquisition of energy data in the production - Technologies and possibilities (Joachim Neher); (8) Active energy management by means of an ''energy control centre'' - Analysis of the real situation and upgrading measures in the production using coating plants as an example (Wolfgang Klein); (9) Visualisation and simulation of energy values in the digital factory (Carmen Constantinescu, Axel Bruns).

Energy Management Strategy for Grid-tied Microgrids considering the Energy Storage Efficiency

DEFF Research Database (Denmark)

Wu, Ji; Xing, Xiaowen; Liu, Xingtao

2018-01-01

developed based on the scheduled power. Experiments are conducted to verify the relationship between battery energy storage efficiency and charging/discharging current of the lithium-ion battery. Moreover, the proposed energy management strategy is validated by the hardware-in-the-loop (HIL) experiments...

Polymer-Polymer Förster Resonance Energy Transfer Significantly Boosts the Power Conversion Efficiency of Bulk-Heterojunction Solar Cells.

Science.gov (United States)

Gupta, Vinay; Bharti, Vishal; Kumar, Mahesh; Chand, Suresh; Heeger, Alan J

2015-08-01

Optically resonant donor polymers can exploit a wider range of the solar spectrum effectively without a complicated tandem design in an organic solar cell. Ultrafast Förster resonance energy transfer (FRET) in a polymer-polymer system that significantly improves the power conversion efficiency in bulk heterojunction polymer solar cells from 6.8% to 8.9% is demonstrated, thus paving the way to achieving 15% efficient solar cells. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Energy efficiency in buildings, industry and transportation

Science.gov (United States)

Milovanovic, Dobrica; Babic, Milun; Jovicic, Nebojsa; Gordic, Dusan

2012-11-01

This paper reviews the literature concerning the energy saving and outlines the importance of energy efficiency, particularly in three the most important areas: buildings, industry and transportation. Improving energy efficiency plays a crucial role in minimizing the societal and environmental impacts of economic growth and offers a powerful tool for achieving sustainable development by reducing the need for investment in new infrastructure, by cutting fuel costs, and by increasing competitiveness for businesses and welfare for consumers. It creates environmental benefits through reduced emissions of greenhouse gases and local air pollutants. It can offer social benefits in the form of increased energy security (through reduced dependence on fossil fuels, particularly when imported) and better energy services.

A High-Efficiency Wind Energy Harvester for Autonomous Embedded Systems.

Science.gov (United States)

Brunelli, Davide

2016-03-04

Energy harvesting is currently a hot research topic, mainly as a consequence of the increasing attractiveness of computing and sensing solutions based on small, low-power distributed embedded systems. Harvesting may enable systems to operate in a deploy-and-forget mode, particularly when power grid is absent and the use of rechargeable batteries is unattractive due to their limited lifetime and maintenance requirements. This paper focuses on wind flow as an energy source feasible to meet the energy needs of a small autonomous embedded system. In particular the contribution is on the electrical converter and system integration. We characterize the micro-wind turbine, we define a detailed model of its behaviour, and then we focused on a highly efficient circuit to convert wind energy into electrical energy. The optimized design features an overall volume smaller than 64 cm³. The core of the harvester is a high efficiency buck-boost converter which performs an optimal power point tracking. Experimental results show that the wind generator boosts efficiency over a wide range of operating conditions.

A High-Efficiency Wind Energy Harvester for Autonomous Embedded Systems

Science.gov (United States)

Brunelli, Davide

2016-01-01

Energy harvesting is currently a hot research topic, mainly as a consequence of the increasing attractiveness of computing and sensing solutions based on small, low-power distributed embedded systems. Harvesting may enable systems to operate in a deploy-and-forget mode, particularly when power grid is absent and the use of rechargeable batteries is unattractive due to their limited lifetime and maintenance requirements. This paper focuses on wind flow as an energy source feasible to meet the energy needs of a small autonomous embedded system. In particular the contribution is on the electrical converter and system integration. We characterize the micro-wind turbine, we define a detailed model of its behaviour, and then we focused on a highly efficient circuit to convert wind energy into electrical energy. The optimized design features an overall volume smaller than 64 cm3. The core of the harvester is a high efficiency buck-boost converter which performs an optimal power point tracking. Experimental results show that the wind generator boosts efficiency over a wide range of operating conditions. PMID:26959018

A High-Efficiency Wind Energy Harvester for Autonomous Embedded Systems

Directory of Open Access Journals (Sweden)

Davide Brunelli

2016-03-01

Full Text Available Energy harvesting is currently a hot research topic, mainly as a consequence of the increasing attractiveness of computing and sensing solutions based on small, low-power distributed embedded systems. Harvesting may enable systems to operate in a deploy-and-forget mode, particularly when power grid is absent and the use of rechargeable batteries is unattractive due to their limited lifetime and maintenance requirements. This paper focuses on wind flow as an energy source feasible to meet the energy needs of a small autonomous embedded system. In particular the contribution is on the electrical converter and system integration. We characterize the micro-wind turbine, we define a detailed model of its behaviour, and then we focused on a highly efficient circuit to convert wind energy into electrical energy. The optimized design features an overall volume smaller than 64 cm3. The core of the harvester is a high efficiency buck-boost converter which performs an optimal power point tracking. Experimental results show that the wind generator boosts efficiency over a wide range of operating conditions.

Comparing Server Energy Use and Efficiency Using Small Sample Sizes

Energy Technology Data Exchange (ETDEWEB)

Coles, Henry C.; Qin, Yong; Price, Phillip N.

2014-11-01

This report documents a demonstration that compared the energy consumption and efficiency of a limited sample size of server-type IT equipment from different manufacturers by measuring power at the server power supply power cords. The results are specific to the equipment and methods used. However, it is hoped that those responsible for IT equipment selection can used the methods described to choose models that optimize energy use efficiency. The demonstration was conducted in a data center at Lawrence Berkeley National Laboratory in Berkeley, California. It was performed with five servers of similar mechanical and electronic specifications; three from Intel and one each from Dell and Supermicro. Server IT equipment is constructed using commodity components, server manufacturer-designed assemblies, and control systems. Server compute efficiency is constrained by the commodity component specifications and integration requirements. The design freedom, outside of the commodity component constraints, provides room for the manufacturer to offer a product with competitive efficiency that meets market needs at a compelling price. A goal of the demonstration was to compare and quantify the server efficiency for three different brands. The efficiency is defined as the average compute rate (computations per unit of time) divided by the average energy consumption rate. The research team used an industry standard benchmark software package to provide a repeatable software load to obtain the compute rate and provide a variety of power consumption levels. Energy use when the servers were in an idle state (not providing computing work) were also measured. At high server compute loads, all brands, using the same key components (processors and memory), had similar results; therefore, from these results, it could not be concluded that one brand is more efficient than the other brands. The test results show that the power consumption variability caused by the key components as a

Optimization of output power and transmission efficiency of magnetically coupled resonance wireless power transfer system

Science.gov (United States)

Yan, Rongge; Guo, Xiaoting; Cao, Shaoqing; Zhang, Changgeng

2018-05-01

Magnetically coupled resonance (MCR) wireless power transfer (WPT) system is a promising technology in electric energy transmission. But, if its system parameters are designed unreasonably, output power and transmission efficiency will be low. Therefore, optimized parameters design of MCR WPT has important research value. In the MCR WPT system with designated coil structure, the main parameters affecting output power and transmission efficiency are the distance between the coils, the resonance frequency and the resistance of the load. Based on the established mathematical model and the differential evolution algorithm, the change of output power and transmission efficiency with parameters can be simulated. From the simulation results, it can be seen that output power and transmission efficiency of the two-coil MCR WPT system and four-coil one with designated coil structure are improved. The simulation results confirm the validity of the optimization method for MCR WPT system with designated coil structure.

A Study on Efficient Energy Use for Household Appliances in Malawi

African Journals Online (AJOL)

Keywords: Efficient , energy use, household appliances, power consumption. ... Although the hydro-electric power transmission lines extend the entire length of ..... R. Karri and P. Mishra, “Minimizing Energy Consumption of Secure Wireless ...

High-power, high-efficiency FELs

International Nuclear Information System (INIS)

Sessler, A.M.

1989-04-01

High power, high efficiency FELs require tapering, as the particles loose energy, so as to maintain resonance between the electromagnetic wave and the particles. They also require focusing of the particles (usually done with curved pole faces) and focusing of the electromagnetic wave (i.e. optical guiding). In addition, one must avoid transverse beam instabilities (primarily resistive wall) and longitudinal instabilities (i.e sidebands). 18 refs., 7 figs., 3 tabs

Energy Efficiency Perspectives of PMR Networks

Directory of Open Access Journals (Sweden)

Marco Dolfi

2016-12-01

Full Text Available Recently, the concern about energy efficiency in wireless communications has been growing rapidly. Manufacturers and researchers have developed innovative solutions, highlighting the benefits in reducing operational expenditures (OPEX and carbon footprint. Professional Mobile Radio (PMR systems, like Terrestrial Trunked Radio (TETRA, have been designed to provide voice and data services to professional users. The energy consumption is one of the critical aspects of PMR broadband solutions and a major constraint for PMR services. The future convergence of PMR to the LTE system introduces a new topic in the research discussion about the energy efficiency of wireless systems. This paper focuses on the feasibility of energy efficient solutions for current and potentially future PMR networks, by providing a mathematical formulation of power consumption in TETRA base stations and assessing possible business models and energy saving solutions for enhanced mission-critical operations. The energy efficiency evaluation has been performed by taking into account the traffic load of a deployed TETRA regional network: in the considered network scenario with 150 base stations, significant OPEX savings up to 70 thousand Euros per year of operation are achieved. Moreover, the proposed solutions allow for saving more than 1 ton of CO 2 per year.

Renewable and efficient electric power systems

CERN Document Server

Masters, Gilbert M

2013-01-01

A solid, quantitative, practical introduction to a wide range of renewable energy systems-in a completely updated, new edition The second edition of Renewable and Efficient Electric Power Systems provides a solid, quantitative, practical introduction to a wide range of renewable energy systems. For each topic, essential theoretical background is introduced, practical engineering considerations associated with designing systems and predicting their performance are provided, and methods for evaluating the economics of these systems are presented. While the book focuses on

Flexible Grouping for Enhanced Energy Utilization Efficiency in Battery Energy Storage Systems

Directory of Open Access Journals (Sweden)

Weiping Diao

2016-06-01

Full Text Available As a critical subsystem in electric vehicles and smart grids, a battery energy storage system plays an essential role in enhancement of reliable operation and system performance. In such applications, a battery energy storage system is required to provide high energy utilization efficiency, as well as reliability. However, capacity inconsistency of batteries affects energy utilization efficiency dramatically; and the situation becomes more severe after hundreds of cycles because battery capacities change randomly due to non-uniform aging. Capacity mismatch can be solved by decomposing a cluster of batteries in series into several low voltage battery packs. This paper introduces a new analysis method to optimize energy utilization efficiency by finding the best number of batteries in a pack, based on capacity distribution, order statistics, central limit theorem, and converter efficiency. Considering both battery energy utilization and power electronics efficiency, it establishes that there is a maximum energy utilization efficiency under a given capacity distribution among a certain number of batteries, which provides a basic analysis for system-level optimization of a battery system throughout its life cycle. Quantitative analysis results based on aging data are illustrated, and a prototype of flexible energy storage systems is built to verify this analysis.

Efficiency analysis of a cogeneration and district energy system

International Nuclear Information System (INIS)

Rosen, Marc A.; Le, Minh N.; Dincer, Ibrahim

2005-01-01

This paper presents an efficiency analysis, accounting for both energy and exergy considerations, of a design for a cogeneration-based district energy system. A case study is considered for the city of Edmonton, Canada, by the utility Edmonton Power. The original concept using central electric chillers, as well as two variations (one considering single-effect and the other double-effect absorption chillers) are examined. The energy- and exergy-based results differ markedly (e.g., overall energy efficiencies are shown to vary for the three configurations considered from 83% to 94%, and exergy efficiencies from 28% to 29%, respectively). For the overall processes, as well as individual subprocesses and selected combinations of subprocesses, the exergy efficiencies are generally found to be more meaningful and indicative of system behaviour than the energy efficiencies

Energy Efficiency Plan 2009-2012; Energie Efficiency Plan 2009-2012

Energy Technology Data Exchange (ETDEWEB)

Meulen, M.M.W. (ed.)

2009-02-15

The aim of the Energy Efficiency Plan is to give an overview of the energy conservation plans of the Eindhoven University of Technology in Eindhoven, Netherlands, which must result in efficient use of energy conform the long-range agreements between businesses, industry and organizations and the Dutch government to improve energy efficiency (MJA3) [Dutch] Het doel van het EEP (Energie Efficiency Plan) is het in beeld brengen van de energiebesparingsplannen die leiden tot een efficienter gebruik van energie conform de MJA-3 afspraak (de derde Meerjaren Afspraak)

Energy audit: thermal power, combined cycle, and cogeneration plants

Energy Technology Data Exchange (ETDEWEB)

Abbi, Yash Pal

2012-07-01

The availability of fossil fuels required for power plants is reducing and their costs increasing rapidly. This gives rise to increase in the cost of generation of electricity. But electricity regulators have to control the price of electricity so that consumers are not stressed with high costs. In addition, environmental considerations are forcing power plants to reduce CO2 emissions. Under these circumstances, power plants are constantly under pressure to improve the efficiency of operating plants, and to reduce fuel consumption. In order to progress in this direction, it is important that power plants regularly audit their energy use in terms of the operating plant heat rate and auxiliary power consumption. The author attempts to refresh the fundamentals of the science and engineering of thermal power plants, establish its link with the real power plant performance data through case studies, and further develop techno-economics of the energy efficiency improvement measures. This book will rekindle interest in energy audits and analysis of the data for designing and implementation of energy conservation measures on a continuous basis.

Energy Conversion Alternatives Study (ECAS), Westinghouse phase 1. Volume 12: Fuel cells. [energy conversion efficiency of, for use in electric power plants

Science.gov (United States)

Warde, C. J.; Ruka, R. J.; Isenberg, A. O.

1976-01-01

A parametric assessment of four fuel cell power systems -- based on phosphoric acid, potassium hydroxide, molten carbonate, and stabilized zirconia -- has shown that the most important parameters for electricity-cost reduction and/or efficiency improvement standpoints are fuel cell useful life and power density, use of a waste-heat recovery system, and fuel type. Typical capital costs, overall energy efficiencies (based on the heating value of the coal used to produce the power plant fuel), and electricity costs are: phosphoric acid $350-450/kWe, 24-29%, and 11.7 to 13.9 mills/MJ (42 to 50 mills/kWh); alkaline $450-700/kWe, 26-31%, and 12.8 to 16.9 mills/MJ (46 to 61 mills/kWh); molten carbonate $480-650/kWe, 32-46%, and 10.6 to 19.4 mills/MJ (38 to 70 mills/kWh), stabilized zirconia $420-950/kWe, 26-53%, and 9.7 to 16.9 mills/MJ (35 to 61 mills/kWh). Three types of fuel cell power plants -- solid electrolytic with steam bottoming, molten carbonate with steam bottoming, and solid electrolyte with an integrated coal gasifier -- are recommended for further study.

US energy conservation and efficiency policies: Challenges and opportunities

International Nuclear Information System (INIS)

Dixon, Robert K.; McGowan, Elizabeth; Onysko, Ganna; Scheer, Richard M.

2010-01-01

Expanding energy conservation and efficiency in every sector nationwide is one of the most cost-effective instruments for reducing US energy imports, the trade deficit and energy's environmental impacts. For these reasons, energy conservation and efficiency have been essential elements of US energy policy since the oil embargos and price spikes of the 1970s. The Energy Independence and Security Act of 2007 (EISA) is the latest federal legislation to expand and strengthen US energy conservation and efficiency policies, programs, and practices. Specifically, EISA and its recent predecessor, the Energy Policy Act of 2005 (EPAct05), contain almost 200 titles with new provisions for energy conservation and efficiency aimed at improvements in vehicle fuel economy. These provisions include efficiency of appliances and lighting; energy savings in residential, commercial, and government buildings; the efficiency of industrial manufacturing plants; and the efficiency of electric power delivery and end-use. These actions have begun to contribute to new federal, state, and local policies, programs, and practices across the US, and expectations are high for increases in the level of energy savings. This paper summarizes the history of US energy conservation and efficiency policies, outlines EISA's and EPAct05's key provisions, and considers prospects for the future.

US energy conservation and efficiency policies. Challenges and opportunities

Energy Technology Data Exchange (ETDEWEB)

Dixon, Robert K.; Onysko, Ganna [Global Environment Facility, Climate Change and Chemicals, 1818 H Street, NW, MSN G6-602, Washington, DC 20433 (United States); McGowan, Elizabeth; Scheer, Richard M. [Energetics Incorporated, 7067 Columbia Gateway Drive, Suite 200, Columbia, MD 21046 (United States)

2010-11-15

Expanding energy conservation and efficiency in every sector nationwide is one of the most cost-effective instruments for reducing US energy imports, the trade deficit and energy's environmental impacts. For these reasons, energy conservation and efficiency have been essential elements of US energy policy since the oil embargos and price spikes of the 1970s. The Energy Independence and Security Act of 2007 (EISA) is the latest federal legislation to expand and strengthen US energy conservation and efficiency policies, programs, and practices. Specifically, EISA and its recent predecessor, the Energy Policy Act of 2005 (EPAct05), contain almost 200 titles with new provisions for energy conservation and efficiency aimed at improvements in vehicle fuel economy. These provisions include efficiency of appliances and lighting; energy savings in residential, commercial, and government buildings; the efficiency of industrial manufacturing plants; and the efficiency of electric power delivery and end-use. These actions have begun to contribute to new federal, state, and local policies, programs, and practices across the US, and expectations are high for increases in the level of energy savings. This paper summarizes the history of US energy conservation and efficiency policies, outlines EISA's and EPAct05's key provisions, and considers prospects for the future. (author)

US energy conservation and efficiency policies: Challenges and opportunities

Energy Technology Data Exchange (ETDEWEB)

Dixon, Robert K. [Global Environment Facility, Climate Change and Chemicals, 1818 H Street, NW, MSN G6-602, Washington, DC 20433 (United States); McGowan, Elizabeth [Energetics Incorporated, 7067 Columbia Gateway Drive, Suite 200, Columbia, MD 21046 (United States); Onysko, Ganna, E-mail: gonysko@thegef.or [Global Environment Facility, Climate Change and Chemicals, 1818 H Street, NW, MSN G6-602, Washington, DC 20433 (United States); Scheer, Richard M. [Energetics Incorporated, 7067 Columbia Gateway Drive, Suite 200, Columbia, MD 21046 (United States)

2010-11-15

Expanding energy conservation and efficiency in every sector nationwide is one of the most cost-effective instruments for reducing US energy imports, the trade deficit and energy's environmental impacts. For these reasons, energy conservation and efficiency have been essential elements of US energy policy since the oil embargos and price spikes of the 1970s. The Energy Independence and Security Act of 2007 (EISA) is the latest federal legislation to expand and strengthen US energy conservation and efficiency policies, programs, and practices. Specifically, EISA and its recent predecessor, the Energy Policy Act of 2005 (EPAct05), contain almost 200 titles with new provisions for energy conservation and efficiency aimed at improvements in vehicle fuel economy. These provisions include efficiency of appliances and lighting; energy savings in residential, commercial, and government buildings; the efficiency of industrial manufacturing plants; and the efficiency of electric power delivery and end-use. These actions have begun to contribute to new federal, state, and local policies, programs, and practices across the US, and expectations are high for increases in the level of energy savings. This paper summarizes the history of US energy conservation and efficiency policies, outlines EISA's and EPAct05's key provisions, and considers prospects for the future.

Hybrid pressure retarded osmosis-membrane distillation system for power generation from low-grade heat: thermodynamic analysis and energy efficiency.

Science.gov (United States)

Lin, Shihong; Yip, Ngai Yin; Cath, Tzahi Y; Osuji, Chinedum O; Elimelech, Menachem

2014-05-06

We present a novel hybrid membrane system that operates as a heat engine capable of utilizing low-grade thermal energy, which is not readily recoverable with existing technologies. The closed-loop system combines membrane distillation (MD), which generates concentrated and pure water streams by thermal separation, and pressure retarded osmosis (PRO), which converts the energy of mixing to electricity by a hydro-turbine. The PRO-MD system was modeled by coupling the mass and energy flows between the thermal separation (MD) and power generation (PRO) stages for heat source temperatures ranging from 40 to 80 °C and working concentrations of 1.0, 2.0, and 4.0 mol/kg NaCl. The factors controlling the energy efficiency of the heat engine were evaluated for both limited and unlimited mass and heat transfer kinetics in the thermal separation stage. In both cases, the relative flow rate between the MD permeate (distillate) and feed streams is identified as an important operation parameter. There is an optimal relative flow rate that maximizes the overall energy efficiency of the PRO-MD system for given working temperatures and concentration. In the case of unlimited mass and heat transfer kinetics, the energy efficiency of the system can be analytically determined based on thermodynamics. Our assessment indicates that the hybrid PRO-MD system can theoretically achieve an energy efficiency of 9.8% (81.6% of the Carnot efficiency) with hot and cold working temperatures of 60 and 20 °C, respectively, and a working solution of 1.0 M NaCl. When mass and heat transfer kinetics are limited, conditions that more closely represent actual operations, the practical energy efficiency will be lower than the theoretically achievable efficiency. In such practical operations, utilizing a higher working concentration will yield greater energy efficiency. Overall, our study demonstrates the theoretical viability of the PRO-MD system and identifies the key factors for performance

Contemporary Targets for Control of Efficient Energy Use

Directory of Open Access Journals (Sweden)

Yu. S. Petrusha

2012-01-01

Full Text Available The paper describes main principles of the methodology for control of efficient energy use in power engineering and economy sectors as a whole. Targets for control of energy use at different levels have been considered in the paper. A special attention has been paid to technical, organizational and legal aspects of energy efficiency improvement. The paper contains an analysis of the history of the given issue, the present level of its development and near-term prospects under conditions of the Republic of Belarus.

Phase change energy storage for solar dynamic power systems

Science.gov (United States)

Chiaramonte, F. P.; Taylor, J. D.

1992-01-01

This paper presents the results of a transient computer simulation that was developed to study phase change energy storage techniques for Space Station Freedom (SSF) solar dynamic (SD) power systems. Such SD systems may be used in future growth SSF configurations. Two solar dynamic options are considered in this paper: Brayton and Rankine. Model elements consist of a single node receiver and concentrator, and takes into account overall heat engine efficiency and power distribution characteristics. The simulation not only computes the energy stored in the receiver phase change material (PCM), but also the amount of the PCM required for various combinations of load demands and power system mission constraints. For a solar dynamic power system in low earth orbit, the amount of stored PCM energy is calculated by balancing the solar energy input and the energy consumed by the loads corrected by an overall system efficiency. The model assumes an average 75 kW SD power system load profile which is connected to user loads via dedicated power distribution channels. The model then calculates the stored energy in the receiver and subsequently estimates the quantity of PCM necessary to meet peaking and contingency requirements. The model can also be used to conduct trade studies on the performance of SD power systems using different storage materials.

Estimating the Impact (Energy, Emissions and Economics) of the US Fluid Power Industry

Energy Technology Data Exchange (ETDEWEB)

Love, Lonnie J [ORNL

2012-12-01

The objective of this report is to estimate the impact (energy, emissions and economics) of United Fluid power (hydraulic and pneumatic actuation) is the generation, control, and application of pumped or compressed fluids when this power is used to provide force and motion to mechanisms. This form of mechanical power is an integral part of United States (U.S.) manufacturing and transportation. In 2008, according to the U.S. Census Bureau, sales of fluid power components exceeded $17.7B, sales of systems using fluid power exceeded $226B. As large as the industry is, it has had little fundamental research that could lead to improved efficiency since the late 1960s (prior to the 1970 energy crisis). While there have been some attempts to replace fluid powered components with electric systems, its performance and rugged operating condition limit the impact of simple part replacement. Oak Ridge National Laboratory and the National Fluid Power Association (NFPA) collaborated with 31 industrial partners to collect and consolidate energy specific measurements (consumption, emissions, efficiency) of deployed fluid power systems. The objective of this study was to establish a rudimentary order of magnitude estimate of the energy consumed by fluid powered systems. The analysis conducted in this study shows that fluid powered systems consumed between 2.0 and 2.9 Quadrillion (1015) Btus (Quads) of energy per year; producing between 310 and 380 million metric tons (MMT) of Carbon Dioxide (CO2). In terms of efficiency, the study indicates that, across all industries, fluid power system efficiencies range from less than 9% to as high as 60% (depending upon the application), with an average efficiency of 22%. A review of case studies shows that there are many opportunities to impact energy savings in both the manufacturing and transportation sectors by the development and deployment of energy efficient fluid power components and systems.

A portable high-efficiency electromagnetic energy harvesting system using supercapacitors for renewable energy applications in railroads

International Nuclear Information System (INIS)

Zhang, Xingtian; Zhang, Zutao; Pan, Hongye; Salman, Waleed; Yuan, Yanping; Liu, Yujie

2016-01-01

Graphical abstract: In this study, we develop a portable high-efficiency electromagnetic energy harvesting system with supercapacitors that converts the energy of track vibrations into electricity. The generated electricity is stored in the supercapacitors and used in remote areas for safety facilities or in standby power supplies for rail-side equipment. The proposed system consists of a mechanical transmission and a rectifier. Acting as the energy input and transmission, Gears and a rack amplify the small vibrations of the track, and one-way bearings enhance efficiency by transforming bidirectional motion to unidirectional rotation. Supercapacitors are used in the energy harvesting system for the first time. The supercapacitors permit the storage of energy from rapidly changing transient currents and a steady power supply for external loads. The proposed system is demonstrated through dynamic simulations, which show the rapid response of the system. An efficiency of 55.5% is demonstrated in bench tests, verifying that the proposed electromagnetic energy harvesting system is effective and practical in renewable energy applications for railroads. - Highlights: • A frequently ignored source of energy, railroad track vibrations, is harvested. • A novel conversion mechanism is designed to maximize efficiency. • Supercapacitors are included in the electromagnetic energy harvesting system. • A portable design is proposed for wider application. - Abstract: As the demand for alternative sources of energy has increased, harvesting abundant environmental energy such as vibration energy including track vibrations in railway systems has attracted greater attention. In this study, we develop a portable high-efficiency electromagnetic energy harvesting system with supercapacitors that converts the energy of track vibrations into electricity. The generated electricity is stored in the supercapacitors and used in remote areas for safety facilities or in standby power

Observations on Power-Efficiency Trends in Mobile Communication Devices

Directory of Open Access Journals (Sweden)

Kari Jyrkkä

2007-03-01

Full Text Available Computing solutions used in mobile communications equipment are similar to those in personal and mainframe computers. The key differences between the implementations at chip level are the low leakage silicon technology and lower clock frequency used in mobile devices. The hardware and software architectures, including the operating system principles, are strikingly similar, although the mobile computing systems tend to rely more on hardware accelerators. As the performance expectations of mobile devices are increasing towards the personal computer level and beyond, power efficiency is becoming a major bottleneck. So far, the improvements of the silicon processes in mobile phones have been exploited by software designers to increase functionality and to cut development time, while usage times, and energy efficiency, have been kept at levels that satisfy the customers. Here we explain some of the observed developments and consider means of improving energy efficiency. We show that both processor and software architectures have a big impact on power consumption. Properly targeted research is needed to find the means to explicitly optimize system designs for energy efficiency, rather than maximize the nominal throughputs of the processor cores used.

Observations on Power-Efficiency Trends in Mobile Communication Devices

Directory of Open Access Journals (Sweden)

Jyrkkä Kari

2007-01-01

Full Text Available Computing solutions used in mobile communications equipment are similar to those in personal and mainframe computers. The key differences between the implementations at chip level are the low leakage silicon technology and lower clock frequency used in mobile devices. The hardware and software architectures, including the operating system principles, are strikingly similar, although the mobile computing systems tend to rely more on hardware accelerators. As the performance expectations of mobile devices are increasing towards the personal computer level and beyond, power efficiency is becoming a major bottleneck. So far, the improvements of the silicon processes in mobile phones have been exploited by software designers to increase functionality and to cut development time, while usage times, and energy efficiency, have been kept at levels that satisfy the customers. Here we explain some of the observed developments and consider means of improving energy efficiency. We show that both processor and software architectures have a big impact on power consumption. Properly targeted research is needed to find the means to explicitly optimize system designs for energy efficiency, rather than maximize the nominal throughputs of the processor cores used.

Techniques and tools for measuring energy efficiency of scientific software applications

International Nuclear Information System (INIS)

Abdurachmanov, David; Elmer, Peter; Eulisse, Giulio; Knight, Robert; Niemi, Tapio; Pestana, Gonçalo; Khan, Kashif; Nurminen, Jukka K; Nyback, Filip; Ou, Zhonghong

2015-01-01

The scale of scientific High Performance Computing (HPC) and High Throughput Computing (HTC) has increased significantly in recent years, and is becoming sensitive to total energy use and cost. Energy-efficiency has thus become an important concern in scientific fields such as High Energy Physics (HEP). There has been a growing interest in utilizing alternate architectures, such as low power ARM processors, to replace traditional Intel x86 architectures. Nevertheless, even though such solutions have been successfully used in mobile applications with low I/O and memory demands, it is unclear if they are suitable and more energy-efficient in the scientific computing environment. Furthermore, there is a lack of tools and experience to derive and compare power consumption between the architectures for various workloads, and eventually to support software optimizations for energy efficiency. To that end, we have performed several physical and software-based measurements of workloads from HEP applications running on ARM and Intel architectures, and compare their power consumption and performance. We leverage several profiling tools (both in hardware and software) to extract different characteristics of the power use. We report the results of these measurements and the experience gained in developing a set of measurement techniques and profiling tools to accurately assess the power consumption for scientific workloads. (paper)

Power-Efficient Computing: Experiences from the COSA Project

Directory of Open Access Journals (Sweden)

Daniele Cesini

2017-01-01

Full Text Available Energy consumption is today one of the most relevant issues in operating HPC systems for scientific applications. The use of unconventional computing systems is therefore of great interest for several scientific communities looking for a better tradeoff between time-to-solution and energy-to-solution. In this context, the performance assessment of processors with a high ratio of performance per watt is necessary to understand how to realize energy-efficient computing systems for scientific applications, using this class of processors. Computing On SOC Architecture (COSA is a three-year project (2015–2017 funded by the Scientific Commission V of the Italian Institute for Nuclear Physics (INFN, which aims to investigate the performance and the total cost of ownership offered by computing systems based on commodity low-power Systems on Chip (SoCs and high energy-efficient systems based on GP-GPUs. In this work, we present the results of the project analyzing the performance of several scientific applications on several GPU- and SoC-based systems. We also describe the methodology we have used to measure energy performance and the tools we have implemented to monitor the power drained by applications while running.

Restructuring and energy efficiency improvement of the Bulgarian energy economy

International Nuclear Information System (INIS)

Moumdjian, G.

1993-01-01

The structure of the national energy economy of Bulgaria implies characteristic features that specify low efficiency as regards power production, ecology and economics. Even the qualitative assessments show that these indices stand far away from the standards established in developed countries like Denmark, Finland, Sweden, etc. The best starting position for harmful energy efficiency improvement as well as emission reduction must be based on the restructuring of energy economy. The strategy of restructuring and development of energy economy covers the whole integrated national energy flow system 'resources - end user'. The preliminary study shows that energy efficiency can be increased by 25-30% within a period of 6-10 years using the least-cost investment strategy (including the research and development activities expenses). The study covers the existing structure of energy sector. Scenarios are being elaborated for its development and restructuring in respect to: heat production and transfer; electricity generation and transmission; energy consumption and conservation in residential buildings, public buildings and commercial sector; energy consumption in transport sector and agriculture. The approach for identification of the real potential opportunities in relation to the above stated areas is based on mathematical statistics and stochastic differential equations, multicriterial assessments, approach of self organisation systems and demand-side management. (author)

Wastewater treatment facilities: Energy efficient improvements and cogeneration

International Nuclear Information System (INIS)

Kunkle, R.; Gray, R.; Delzel, D.

1992-10-01

The Washington State Energy Office (WSEO) has worked with both the Bonneville Power Administration (BPA) and the US Department of Energy to provide technical and financial assistance to local governments. Based on a recent study conducted by Ecotope for WSEO, local governments spend an estimated $45 million on utility bills statewide. Water and wastewater facilities account for almost a third of this cost. As a result, WSEO decided to focus its efforts on the energy intensive water and wastewater sector. The ultimate goal of this project was to develop mechanisms to incorporate energy efficiency improvements into wastewater treatment facilities in retrofits and during upgrades, remodels, and new construction. Project activities included the following: The review of the existing regulatory environment for treatment system construction, A summary of financing options for efficiency improvements in treatment facilities, A literature review of energy efficiency opportunities in treatment plants, Survey and site visits to characterize existing facilities in Washington State, Estimates of the energy efficiency and cogeneration potential in the sector, and A case study to illustrate the implementation of an efficiency improvement in a treatment facility

Advanced energy utilization MHD power generation

International Nuclear Information System (INIS)

2008-01-01

The 'Technical Committee on Advanced Energy Utilization MHD Power Generation' was started to establish advanced energy utilization technologies in Japan, and has been working for three years from June 2004 to May 2007. This committee investigated closed cycle MHD, open cycle MHD, and liquid metal MHD power generation as high-efficiency power generation systems on the earth. Then, aero-space application and deep space exploration technologies were investigated as applications of MHD technology. The spin-off from research and development on MHD power generation such as acceleration and deceleration of supersonic flows was expected to solve unstart phenomena in scramjet engine and also to solve abnormal heating of aircrafts by shock wave. In addition, this committee investigated researches on fuel cells, on secondary batteries, on connection of wind power system to power grid, and on direct energy conversion system from nuclear fusion reactor for future. The present technical report described results of investigations by the committee. (author)

Eco-development and energy efficient technologies in Russia: prospects and reality

Science.gov (United States)

Kurakova, Oksana

2017-10-01

The article highlights the concept of eco-standards in Russia, and discusses new technologies that allow to build energy-efficient houses in the form of countryside real estate. Special attention is given to the principle of heat production based on the use of individual facilities, power centers mini thermal power plants, as well as to ways to reduce water consumption at home. Presents analysis of the advantages projects “built-to-suit” for the introduction of the energy efficient technologies. Justified idea and principles of “green construction” in Russia in the real estate market. Conclusion about the effectiveness of the use, opportunities and development of energy efficient technologies.

Review of FACTS technologies and applications for power quality in smart grids with renewable energy systems

DEFF Research Database (Denmark)

Gandoman, Foad H.; Ahmadi, Abdollah; Sharaf, Adel M.

2018-01-01

In the last two decades, emerging use of renewable and distributed energy sources in electricity grid has created new challenges for the utility regarding the power quality, voltage stabilization and efficient energy utilization. Power electronic converters are extensively utilized to interface...... the power quality. Also, distributed FACTSs play an important role in improving the power factor, energy utilization, enhancing the power quality, and ensuring efficient energy utilization and energy management in smart grids with renewable energy sources. This paper presents a literature survey of FACTS...... technology tools and applications for power quality and efficient renewable energy system utilization....

Sustainable Transportation: Accelerating Widespread Adoption of Energy Efficient Vehicles & Fuels (Brochure)

Energy Technology Data Exchange (ETDEWEB)

2014-12-01

While energy efficient transportation strategies have the potential to simultaneously slash oil consumption and reduce greenhouse gas (GHG) emissions, a truly sustainable solution will require more than just putting drivers behind the wheels of new fuel-efficient cars. As the only national laboratory dedicated 100% to renewable energy and energy efficiency, the National Renewable Energy Laboratory (NREL) accelerates widespread adoption of high-performance, low-emission, energy-efficient passenger and freight vehicles, as well as alternative fuels and related infrastructure. Researchers collaborate closely with industry, government, and research partners, using a whole-systems approach to design better batteries, drivetrains, and engines, as well as thermal management, energy storage, power electronic, climate control, alternative fuel, combustion, and emission systems. NREL's sustainable transportation research, development, and deployment (RD&D) efforts are not limited to vehicles, roads, and fueling stations. The lab also explores ways to save energy and reduce GHGs by integrating transportation technology advancements with renewable energy generation, power grids and building systems, urban planning and policy, and fleet operations.

High to ultra-high power electrical energy storage.

Science.gov (United States)

Sherrill, Stefanie A; Banerjee, Parag; Rubloff, Gary W; Lee, Sang Bok

2011-12-14

High power electrical energy storage systems are becoming critical devices for advanced energy storage technology. This is true in part due to their high rate capabilities and moderate energy densities which allow them to capture power efficiently from evanescent, renewable energy sources. High power systems include both electrochemical capacitors and electrostatic capacitors. These devices have fast charging and discharging rates, supplying energy within seconds or less. Recent research has focused on increasing power and energy density of the devices using advanced materials and novel architectural design. An increase in understanding of structure-property relationships in nanomaterials and interfaces and the ability to control nanostructures precisely has led to an immense improvement in the performance characteristics of these devices. In this review, we discuss the recent advances for both electrochemical and electrostatic capacitors as high power electrical energy storage systems, and propose directions and challenges for the future. We asses the opportunities in nanostructure-based high power electrical energy storage devices and include electrochemical and electrostatic capacitors for their potential to open the door to a new regime of power energy.

Energy use efficiency in the Indian manufacturing sector: An interstate analysis

International Nuclear Information System (INIS)

Mukherjee, Kankana

2008-01-01

This paper approaches the measurement of energy efficiency from a production theoretic framework and uses Data Envelopment Analysis to measure energy efficiency in the Indian manufacturing sector. Using data from the Annual Survey of Industries for the years 1998-99 through 2003-04, the study compares the energy efficiency in manufacturing across states, based on several models. The results show considerable variation in energy efficiency across states. Comparing the results across our models, we find that the relative pricing of energy does not provide the appropriate incentives for energy conservation. A second-stage regression analysis reveals that states with a larger share of manufacturing output in energy-intensive industries have lower energy efficiency. Also, higher quality labor force associates with higher energy efficiency. Finally, the power sector reforms have not yet had any significant impact on achieving energy efficiency

A Novel Energy-Efficient Approach for Human Activity Recognition.

Science.gov (United States)

Zheng, Lingxiang; Wu, Dihong; Ruan, Xiaoyang; Weng, Shaolin; Peng, Ao; Tang, Biyu; Lu, Hai; Shi, Haibin; Zheng, Huiru

2017-09-08

In this paper, we propose a novel energy-efficient approach for mobile activity recognition system (ARS) to detect human activities. The proposed energy-efficient ARS, using low sampling rates, can achieve high recognition accuracy and low energy consumption. A novel classifier that integrates hierarchical support vector machine and context-based classification (HSVMCC) is presented to achieve a high accuracy of activity recognition when the sampling rate is less than the activity frequency, i.e., the Nyquist sampling theorem is not satisfied. We tested the proposed energy-efficient approach with the data collected from 20 volunteers (14 males and six females) and the average recognition accuracy of around 96.0% was achieved. Results show that using a low sampling rate of 1Hz can save 17.3% and 59.6% of energy compared with the sampling rates of 5 Hz and 50 Hz. The proposed low sampling rate approach can greatly reduce the power consumption while maintaining high activity recognition accuracy. The composition of power consumption in online ARS is also investigated in this paper.

Low Li+ Insertion Barrier Carbon for High Energy Efficient Lithium-Ion Capacitor.

Science.gov (United States)

Lee, Wee Siang Vincent; Huang, Xiaolei; Tan, Teck Leong; Xue, Jun Min

2018-01-17

Lithium-ion capacitor (LIC) is an attractive energy-storage device (ESD) that promises high energy density at moderate power density. However, the key challenge in its design is the low energy efficient negative electrode, which barred the realization of such research system in fulfilling the current ESD technological inadequacy due to its poor overall energy efficiency. Large voltage hysteresis is the main issue behind high energy density alloying/conversion-type materials, which reduces the electrode energy efficiency. Insertion-type material though averted in most research due to the low capacity remains to be highly favorable in commercial application due to its lower voltage hysteresis. To further reduce voltage hysteresis and increase capacity, amorphous carbon with wider interlayer spacing has been demonstrated in the simulation result to significantly reduce Li + insertion barrier. Hence, by employing such amorphous carbon, together with disordered carbon positive electrode, a high energy efficient LIC with round-trip energy efficiency of 84.3% with a maximum energy density of 133 Wh kg -1 at low power density of 210 W kg -1 can be achieved.

Energy-Efficient Optimization for HARQ Schemes over Time-Correlated Fading Channels

KAUST Repository

Shi, Zheng

2018-03-19

Energy efficiency of three common hybrid automatic repeat request (HARQ) schemes including Type I HARQ, HARQ with chase combining (HARQ-CC) and HARQ with incremental redundancy (HARQ-IR), is analyzed and joint power allocation and rate selection to maximize the energy efficiency is investigated in this paper. Unlike prior literature, time-correlated fading channels is considered and two widely concerned quality of service (QoS) constraints, i.e., outage and goodput constraints, are also considered in the optimization, which further differentiates this work from prior ones. Using a unified expression of asymptotic outage probabilities, optimal transmission powers and optimal rate are derived in closed-forms to maximize the energy efficiency while satisfying the QoS constraints. These closed-form solutions then enable a thorough analysis of the maximal energy efficiencies of various HARQ schemes. It is revealed that with low outage constraint, the maximal energy efficiency achieved by Type I HARQ is $\\\\frac{1}{4\\\\ln2}$ bits/J, while HARQ-CC and HARQ-IR can achieve the same maximal energy efficiency as $\\\\frac{\\\\kappa_\\\\infty}{4\\\\ln2}$ bits/J where $\\\\kappa_\\\\infty = 1.6617$. Moreover, time correlation in the fading channels has a negative impact on the energy efficiency, while large maximal allowable number of transmissions is favorable for the improvement of energy efficiency. The effectiveness of the energy-efficient optimization is verified by extensive simulations and the results also show that HARQ-CC can achieve the best tradeoff between energy efficiency and spectral efficiency among the three HARQ schemes.