본문 바로가기
HOME> 저널/프로시딩 > 저널/프로시딩 검색상세

저널/프로시딩 상세정보

권호별목차 / 소장처보기

H : 소장처정보

T : 목차정보

Energies 311건

  1. [해외논문]   Experimental and Numerical Study of an Electrical Thermal Storage Device for Space Heating   SCIE SCOPUS

    Xu, Guizhi , Hu, Xiao , Liao, Zhirong , Xu, Chao , Yang, Cenyu , Deng, Zhanfeng
    Energies v.11 no.9 ,pp. 2180 , 2018 ,

    초록

    An electrical thermal storage (ETS) device for space heating is designed in this study. The proposed device is charged by the off-peak electricity and releases its thermal energy to warm the space all day long. The natural convection occurring in the flow channel drives the flowing of air to be heated up and warm the space. The dynamic process of a fully charging/discharging cycle of the device is tested. Meanwhile, a three-dimensional model is developed to simulate the transient thermal behavior. It is found that the experimental and numerical results agree with each other which indicates the validation of the proposed numerical model. The results show that the temperatures of the bricks and the outlet air can be as high as 1002 K and 835 K, respectively. The natural convection occurring in the flow channel transfers 40.4% of the total electrical heating energy to the space for the charging process and 26.9% for the discharging process. Heat losses to the space through the adiabatic material shares 13.3% of the total heating energy for the charging process and 7.2% for the discharging process. Based on those findings, three methods are recommended to improve the device in the successive research.

    원문보기

    원문보기
    무료다운로드 유료다운로드

    회원님의 원문열람 권한에 따라 열람이 불가능 할 수 있으며 권한이 없는 경우 해당 사이트의 정책에 따라 회원가입 및 유료구매가 필요할 수 있습니다.이동하는 사이트에서의 모든 정보이용은 NDSL과 무관합니다.

    NDSL에서는 해당 원문을 복사서비스하고 있습니다. 아래의 원문복사신청 또는 장바구니담기를 통하여 원문복사서비스 이용이 가능합니다.

    이미지

    Fig. 1 이미지
  2. [해외논문]   SDC-Infiltrated Microporous Silver Membrane with Superior Resistance to Thermal Agglomeration for Cathode-Supported Solid Oxide Fuel Cells   SCIE SCOPUS

    Lee, Tsung-Han , Baek, Jong , Fan, Liangdong , Wiria, Florencia , Su, Pei-Chen , Lee, Seong
    Energies v.11 no.9 ,pp. 2181 , 2018 ,

    초록

    This work presents a microporous silver cathode membrane reinforced with infiltration of samarium-doped ceria (SDC). The ion-conducting SDC effectively confines the surface of a porous silver membrane to maintain microporous structure and prevents the electrode agglomeration. SDC precursor solution is fired together with silver membrane at 700 °C for 2 h and formed as a nanocrystalline SDC on the silver pore surface. The SDC-infiltrated microporous silver membrane shows superior resistance to agglomeration without noticeable change in microstructures even at 900 °C for 12 h, which makes it promising for the application of solid oxide fuel cells as a cathode support.

    원문보기

    원문보기
    무료다운로드 유료다운로드

    회원님의 원문열람 권한에 따라 열람이 불가능 할 수 있으며 권한이 없는 경우 해당 사이트의 정책에 따라 회원가입 및 유료구매가 필요할 수 있습니다.이동하는 사이트에서의 모든 정보이용은 NDSL과 무관합니다.

    NDSL에서는 해당 원문을 복사서비스하고 있습니다. 아래의 원문복사신청 또는 장바구니담기를 통하여 원문복사서비스 이용이 가능합니다.

    이미지

    Fig. 1 이미지
  3. [해외논문]   Energy and Economic Analysis of Energy Savings Measures in a Swimming Pool Centre by Means of Dynamic Simulations   SCIE SCOPUS

    Calise, Francesco , Figaj, Rafal , Vanoli, Laura
    Energies v.11 no.9 ,pp. 2182 , 2018 ,

    초록

    Sport centres thermal demand is extremely high due to the large amount of sanitary hot water production. Therefore, energy savings actions must be performed in order to optimize system efficiency. In this framework, the present paper investigates the possibility to perform an energy rehabilitation of an indoor swimming pool centre by means of solar thermal collectors and heat pump technologies integrated with the existing plant. The case study consists of a university indoor swimming pool centre located in Naples, South of Italy. A dynamic simulation model is developed by TRNSYS software (Thermal Energy System Specialists, LLC, Madison, WI, USA). An experimental investigation is also performed in order to calibrate the swimming pool thermal model and the space conditioning equipment operation. Real data concerning the thermal demand of the centre are implemented and the dynamic behaviour of the swimming pool occupants is also considered. The proposed technical solutions are analysed from an energy and economic point of view. A parametric analysis aiming at determining the effect of the size of the solar field on the system performance is performed. The comparison outlines that the best energy and economic performance is achieved by evacuated solar thermal collectors. In particular, the Simple Pay Back (SPB) period results about 14 years without incentives and it decreases to 5 years considering the Italian incentive policy. For an evacuated collector field of 150 m2, the SPB without incentive results below 9 years.

    원문보기

    원문보기
    무료다운로드 유료다운로드

    회원님의 원문열람 권한에 따라 열람이 불가능 할 수 있으며 권한이 없는 경우 해당 사이트의 정책에 따라 회원가입 및 유료구매가 필요할 수 있습니다.이동하는 사이트에서의 모든 정보이용은 NDSL과 무관합니다.

    NDSL에서는 해당 원문을 복사서비스하고 있습니다. 아래의 원문복사신청 또는 장바구니담기를 통하여 원문복사서비스 이용이 가능합니다.

    이미지

    Fig. 1 이미지
  4. [해외논문]   On the Injection of Sub/Inter-Harmonic Current Components for Active Anti-Islanding Purposes   SCIE SCOPUS

    Voglitsis, Dionisis , Valsamas, Fotis , Rigogiannis, Nick , Papanikolaou, Nick
    Energies v.11 no.9 ,pp. 2183 , 2018 ,

    초록

    Active anti-islanding schemes that are based on the injection of harmonic currents, such as the measurement of the impedance at a specific frequency or similar techniques, have been proposed for anti-islanding protection in photovoltaic (PV) systems due to their low impact on inverter active power, their fast detection response in island, and reduced non-detection zone (NDZ). Integer multiples of the fundamental frequency as well as sub/inter-harmonics have both been used for the implementation of those schemes. Although utilization of sub/inter-harmonics present significant advantages, they also present significant limitations. This work investigates those limitations, particularly the ones that are caused by the parallel operation of multiple inverters. In addition, the distortion effect that is caused in the output current of the widely used PV microinverters with pseudo dc-link (PV Pdc-MICs) is discussed and thoroughly analyzed. It is concluded that when the injection is performed asynchronously (without communication among the inverters) sub/inter-harmonics are unsuitable for utilization under the parallel operation of multiple inverters. It is worth noting that a strategy is proposed in the current work that retains the effectiveness of the harmonic injection scheme under the injection of integer multiples of fundamental frequency. On the other hand, the distortion effect that is caused by the sub/inter-harmonics on PV Pdc-MICs output current, has been evaluated as insignificant when harmonics are used for anti-islanding purposes. Finally, the theoretical/mathematical outcomes of this work are supported by simulation and experimental results.

    원문보기

    원문보기
    무료다운로드 유료다운로드

    회원님의 원문열람 권한에 따라 열람이 불가능 할 수 있으며 권한이 없는 경우 해당 사이트의 정책에 따라 회원가입 및 유료구매가 필요할 수 있습니다.이동하는 사이트에서의 모든 정보이용은 NDSL과 무관합니다.

    NDSL에서는 해당 원문을 복사서비스하고 있습니다. 아래의 원문복사신청 또는 장바구니담기를 통하여 원문복사서비스 이용이 가능합니다.

    이미지

    Fig. 1 이미지
  5. [해외논문]   CO2 Pipeline Design: A Review   SCIE SCOPUS

    Peletiri, Suoton , Rahmanian, Nejat , Mujtaba, Iqbal
    Energies v.11 no.9 ,pp. 2184 , 2018 ,

    초록

    There is a need to accurately design pipelines to meet the expected increase in the construction of carbon dioxide (CO2) pipelines after the signing of the Paris Climate Agreement. CO2 pipelines are usually designed with the assumption of a pure CO2 fluid, even though it usually contains impurities, which affect the critical pressure, critical temperature, phase behaviour, and pressure and temperature changes in the pipeline. The design of CO2 pipelines and the calculation of process parameters and fluid properties is not quite accurate with the assumption of pure CO2 fluids. This paper reviews the design of rich CO2 pipelines including pipeline route selection, length and right of way, fluid flow rates and velocities, need for single point-to-point or trunk pipelines, pipeline operating pressures and temperatures, pipeline wall thickness, fluid stream composition, fluid phases, and pipeline diameter and pressure drop calculations. The performance of a hypothetical pipeline was simulated using gPROMS (ver. 4.2.0) and Aspen HYSYS (ver.10.1) and the results of both software were compared to validate equations. Pressure loss due to fluid acceleration was ignored in the development of the diameter/pressure drop equations. Work is ongoing to incorporate fluid acceleration effect and the effects of impurities to improve the current models.

    원문보기

    원문보기
    무료다운로드 유료다운로드

    회원님의 원문열람 권한에 따라 열람이 불가능 할 수 있으며 권한이 없는 경우 해당 사이트의 정책에 따라 회원가입 및 유료구매가 필요할 수 있습니다.이동하는 사이트에서의 모든 정보이용은 NDSL과 무관합니다.

    NDSL에서는 해당 원문을 복사서비스하고 있습니다. 아래의 원문복사신청 또는 장바구니담기를 통하여 원문복사서비스 이용이 가능합니다.

    이미지

    Fig. 1 이미지
  6. [해외논문]   Computational Fluid Dynamics Approach for Performance Prediction in a Zinc-Air Fuel Cell   SCIE SCOPUS

    Huang, K. , Sangeetha, Thangavel , Cheng, Wu-Fu , Lin, Chunyo , Chen, Po-Tuan
    Energies v.11 no.9 ,pp. 2185 , 2018 ,

    초록

    In this study, we investigated the development of a computational fluid dynamics (CFD) model for simulating the physical and chemical processes in a zinc (Zn)-air fuel cell. Theoretically, the model was based on time-dependent, three-dimensional conservation equations of mass, momentum, and species concentration. The complex electrochemical reactions occurring within the porous electrodes were described by the Butler-Volmer equation with velocity, pressure, current density, and electronic and ionic phase potentials computed in electrodes. The Zn-air fuel cell for the present study comprised of four major components, such as a porous Zn anode electrode, air cathode electrode, liquid potassium hydroxide (KOH) electrolyte, and air flow channels. The numerical results were first compared with the experiments, showing close agreement with the predicted and experimental values of the measured voltage-current data of a single Zn-air fuel cell. Numerical results also exhibited mass fraction contours of oxygen (O2) and zinc oxide (ZnO) in the mid-cross-sectional plane. A parametric study was extended to assess the performance of a Zn-air fuel cell at various cathode and electrolyte parameters.

    원문보기

    원문보기
    무료다운로드 유료다운로드

    회원님의 원문열람 권한에 따라 열람이 불가능 할 수 있으며 권한이 없는 경우 해당 사이트의 정책에 따라 회원가입 및 유료구매가 필요할 수 있습니다.이동하는 사이트에서의 모든 정보이용은 NDSL과 무관합니다.

    NDSL에서는 해당 원문을 복사서비스하고 있습니다. 아래의 원문복사신청 또는 장바구니담기를 통하여 원문복사서비스 이용이 가능합니다.

    이미지

    Fig. 1 이미지
  7. [해외논문]   Bamboo Fiber and Sugarcane Skin as a Bio-Briquette Fuel   SCIE SCOPUS

    Brunerová , , Anna , Roubí , k, Hynek , Brož , ek, Milan
    Energies v.11 no.9 ,pp. 2186 , 2018 ,

    초록

    The present study deals with the issue of bio-briquette fuel produced from specific agriculture residues, namely bamboo fiber (BF) and sugarcane skin (SCS). Both materials originated from Thừa ThiEn Huế province in central Vietnam and were subjected to analysis of their suitability for such a purpose. A densification process using a high-pressure briquetting press proved its practicability for producing bio-briquette fuel. Analysis of fuel parameters exhibited a satisfactory level of all measured quality indicators: ash content Ac (BF-1.16%, SCS-8.62%) and net calorific value NCV (BF-16.92 MJ∙kg−1, SCS-17.23 MJ∙kg−1). Equally, mechanical quality indicators also proved satisfactory; bio-briquette samples' mechanical durability DU occurred at an extremely high level (BF-97.80%, SCS-97.70%), as did their bulk density ρ (BF-986.37 kg·m−3, SCS-1067.08 kg·m−3). Overall evaluation of all observed results and factors influencing the investigated issue proved that both waste biomass materials, bamboo fiber and sugarcane skin, represent suitable feedstock materials for bio-briquette fuel production, and produced bio-briquette samples can be used as high-quality fuels.

    원문보기

    원문보기
    무료다운로드 유료다운로드

    회원님의 원문열람 권한에 따라 열람이 불가능 할 수 있으며 권한이 없는 경우 해당 사이트의 정책에 따라 회원가입 및 유료구매가 필요할 수 있습니다.이동하는 사이트에서의 모든 정보이용은 NDSL과 무관합니다.

    NDSL에서는 해당 원문을 복사서비스하고 있습니다. 아래의 원문복사신청 또는 장바구니담기를 통하여 원문복사서비스 이용이 가능합니다.

    이미지

    Fig. 1 이미지
  8. [해외논문]   Online Coordination of Plug-In Electric Vehicles Considering Grid Congestion and Smart Grid Power Quality   SCIE SCOPUS

    Deilami, Sara
    Energies v.11 no.9 ,pp. 2187 , 2018 ,

    초록

    This paper first introduces the impacts of battery charger and nonlinear load harmonics on smart grids considering random plug-in of electric vehicles (PEVs) without any coordination. Then, a new centralized nonlinear online maximum sensitivity selection-based charging algorithm (NOL-MSSCA) is proposed for coordinating PEVs that minimizes the costs associated with generation and losses considering network and bus total harmonic distortion (THD). The aim is to first attend the high priority customers and charge their vehicles as quickly as possible while postponing the service to medium and low priority consumers to the off-peak hours, considering network, battery and power quality constraints and harmonics. The vehicles were randomly plugged at different locations during a period of 24 h. The proposed PEV coordination is based on the maximum sensitivity selection (MSS), which is the sensitivity of losses (including fundamental and harmonic losses) with respect to the PEV location (PEV bus). The proposed algorithm uses the decoupled harmonic power flow (DHPF) to model the nonlinear loads (including the PEV chargers) as current harmonic sources and computes the harmonic power losses, harmonic voltages and THD of the smart grid. The MSS vectors are easily determined using the entries of the Jacobian matrix of the DHPF program, which includes the spectrums of all injected harmonics by nonlinear electric vehicle (EV) chargers and nonlinear industrial loads. The sensitivity of the objective function (fundamental and harmonic power losses) to the PEVs were then used to schedule PEVs accordingly. The algorithm successfully controls the network THDv level within the standard limit of 5% for low and moderate PEV penetrations by delaying PEV charging activities. For high PEV penetrations, the installation of passive power filters (PPFs) is suggested to reduce the THDv and manage to fully charge the PEVs. Detailed simulations considering random and coordinated charging were performed on the modified IEEE 23 kV distribution system with 22 low voltage residential networks populated with PEVs that have nonlinear battery chargers. Simulation results are provided without/with filters for different penetration levels of PEVs.

    원문보기

    원문보기
    무료다운로드 유료다운로드

    회원님의 원문열람 권한에 따라 열람이 불가능 할 수 있으며 권한이 없는 경우 해당 사이트의 정책에 따라 회원가입 및 유료구매가 필요할 수 있습니다.이동하는 사이트에서의 모든 정보이용은 NDSL과 무관합니다.

    NDSL에서는 해당 원문을 복사서비스하고 있습니다. 아래의 원문복사신청 또는 장바구니담기를 통하여 원문복사서비스 이용이 가능합니다.

    이미지

    Fig. 1 이미지
  9. [해외논문]   Cross-Border Effects on Swiss Electricity Prices in the Light of the Energy Transition   SCIE SCOPUS

    Frauendorfer, Karl , Paraschiv, Florentina , Schü , rle, Michael
    Energies v.11 no.9 ,pp. 2188 , 2018 ,

    초록

    Given the perspective of the Swiss energy policy to support investments in renewable energy sources, it becomes highly relevant at this point to understand cross-border effects of imported electricity on the Swiss electricity prices. We found that German (Phelix) and Swiss (Swissix) electricity prices are cointegrated, given that the two markets are interconnected. We examined the cross-border effects of the German market fundamentals on Swissix, taking into account seasonality aspects. In the context of a dynamic fundamental model, we found that there is a continuous adaption process of electricity prices to market fundamentals and that this effect depends on the season of the year and the time of the day. Model results reveal the substitution effect between traditional fuels and renewable energies due to their alternative use in production and the shift in the merit order curve. Results are of great relevance to Swiss policy makers: Switzerland imports lower electricity prices due to the energy transition in Germany. In particular, because of the high infeed of PV (photovoltaic) during peak hours, the spread between Swissix peak and off-peak prices narrowed significantly over time. Incentives for investments in renewable energies in Switzerland as well as subsidies for hydropower should be considered in the light of these insights.

    원문보기

    원문보기
    무료다운로드 유료다운로드

    회원님의 원문열람 권한에 따라 열람이 불가능 할 수 있으며 권한이 없는 경우 해당 사이트의 정책에 따라 회원가입 및 유료구매가 필요할 수 있습니다.이동하는 사이트에서의 모든 정보이용은 NDSL과 무관합니다.

    NDSL에서는 해당 원문을 복사서비스하고 있습니다. 아래의 원문복사신청 또는 장바구니담기를 통하여 원문복사서비스 이용이 가능합니다.

    이미지

    Fig. 1 이미지
  10. [해외논문]   Comparative Evaluation of a Permanent Magnet Machine Saliency-Based Drive with Sine-Wave and Square-Wave Voltage Injection   SCIE SCOPUS

    Chen, Jyun-You , Yang, Shih-Chin , Tu, Kai-Hsiang
    Energies v.11 no.9 ,pp. 2189 , 2018 ,

    초록

    This paper improves a permanent magnet (PM) machine saliency-based drive performance based on the selection of a suitable injection signal. For the saliency-based position estimation, a persistently high-frequency (HF) voltage signal is injected to obtain a measurable spatial saliency feedback signal. The injection signal can be sine-wave or square-wave alternating current (AC) voltage manipulated by the inverter's pulse width modulation (PWM). Due to the PWM dead-time effect, these HF voltage injection signals might be distorted, leading to secondary harmonics on the saliency signal. In addition, the flux saturation in machine rotors also results in other saliency harmonics. These nonlinear attributes cause position estimation errors on saliency-based drives. In this paper, two different voltage signals are analyzed to find a suited voltage which is less sensitive to these nonlinear attributes. Considering the inverter dead-time, a sine-wave voltage signal reduces its influence on the saliency signal. By contrast, the flux saturation causes the same amount of error on two injection signals. Analytical equations are developed to investigate position errors caused by the dead-time and flux saturation. An interior PM machine with the saliency ratio of 1.41 is tested for the experimental verification.

    원문보기

    원문보기
    무료다운로드 유료다운로드

    회원님의 원문열람 권한에 따라 열람이 불가능 할 수 있으며 권한이 없는 경우 해당 사이트의 정책에 따라 회원가입 및 유료구매가 필요할 수 있습니다.이동하는 사이트에서의 모든 정보이용은 NDSL과 무관합니다.

    NDSL에서는 해당 원문을 복사서비스하고 있습니다. 아래의 원문복사신청 또는 장바구니담기를 통하여 원문복사서비스 이용이 가능합니다.

    이미지

    Fig. 1 이미지

논문관련 이미지