Search results for "Energy engineering"
showing 10 items of 1099 documents
Double cross-linked polyetheretherketone proton exchange membrane for fuel cell
2012
Abstract The proton exchange membrane based on polyetheretherketone was prepared via two steps of cross-linking. The properties of the double cross-linked membrane (water uptake, proton conductivity, methanol permeability and thermal stability) have been investigated for fuel cell applications. The prepared membrane exhibited relatively high proton conductivity, 3.2 × 10 −2 S cm −1 at room temperature and 5.8 × 10 −2 S cm −1 at 80 °C. The second cross-linking significantly decreased the water uptake of the membrane. The performance of direct methanol fuel cell was slightly improved as compared to Nafion ® 117 due to its low methanol permeability. The results indicated that the double cros…
Catalytic performance of CoAlZn and NiAlZn mixed oxides in hydrogen production by bio-ethanol partial oxidation
2013
CoAlZn and NiAlZn mixed oxides were prepared by sol-gel method and tested in partial oxidation of bio-ethanol (POE). At lower temperatures, CoAlZn showed higher ethanol conversion and higher selectivity to H2 and CO than NiAlZn. At higher temperatures, ethanol conversion on both catalysts reached 100%, while selectivity (S) to H2 and CO became higher on NiAlZn. At 750 C, NiAlZn showed S(H2) of 95%, S(CO) of 90%, while for CoAlZn these values were 90% and 83% respectively. Both catalysts were resistant to coking, but the amount of carbon deposits was still lower on NiAlZn. During 50 h on-stream, ethanol conversion and selectivity to H2 and CO on NiAlZn remained unchanged demonstrating stable…
Riga experience in spallation neutron target related investigations
2002
Abstract Mercury has awakened interest as a potential material for spallation neutron source targets. Institute of Physics, University of Latvia has a 30 years experience of investigations in mercury. As specially projected building includes a 350 m2 experimental hall. The largest loop, containing 5×103 kg of Hg, can be transferred for solution of different tasks. As the first example results are presented when integral developed pressure and local (distribution of void fraction) characteristics of a two-phase mercury/gas riser were investigated. Second example – investigation of velocity fields and heat transfer conditions close to the beam entrance window in the SINQ target thermohydrauli…
Advances in Anodic Alumina Membranes-based fuel cell: CsH2PO4 pore-filler as proton conductor at room temperature
2009
Abstract Anodic alumina membranes (AAM) filled with cesium hydrogen phosphate proton conductor have been tested as inorganic composite electrolyte for hydrogen–oxygen thin film (≤50 μm) fuel cell (TFFC) working at low temperatures (25 °C), low humidity ( T gas = 25 °C) and low Pt loading (1 mg cm −2 ). Single module TFFC delivering a peak power of around 15–27 mW cm −2 , with open circuit voltage (OCV) of about 0.9 V and short circuit current density in the range 80–160 mA cm −2 have been fabricated. At variance with pure solid acid electrolytes showing reproducibility problems due to the scarce mechanical resistance, the presence of porous alumina support allowed to replicate similar fuel…
Methanol and proton transport through chitosan-phosphotungstic acid membranes for direct methanol fuel cell
2020
Composite chitosan-phosphotungstic acid membranes were synthesized by ionotropic gelation. Their liquid uptake is higher for thin membranes (23 ± 2 μm), while it is lower (~70%) for thicker membranes (50-70 μm). Polarization curves recorded using single module fuel cell at 70°C allowed to estimate a peak power density of 60 mW cm−2 by using 1 M as methanol and low Pt and Pt/Ru loadings (0.5 and 3 mg cm−2) at the cathode and at the anode, respectively. Electrochemical impedance spectroscopy was used to estimate the membrane conductivity and to model the electrochemical behavior of methanol electrooxidation inside the fuel cell revealing a two-step mechanism mainly responsible of overall kine…
Assessment of energy management technique for achieving the sustainable voltage level during grid outage of hydro generator interfaced DC Micro-Grid
2021
Abstract An appropriate energy management scheme is needed for the reliable and sustainable operation of DC microgrid. The energy management scheme of DC microgrid (MG) is mainly controlled by main energy resource of MG. Main energy resource needs to be dispatchable unit for forming the reference voltage within DC MG. In this work, a micro hydro generator (MHG) is considered as a dispatchable source for forming the sustainable voltage level of DC MG operating under the abnormal condition. In this work, the abnormality refers to the outage of solar PV due to intermittency during fluctuating load condition. But, due to mechanical time constant of MHG and rate of charging/discharging current l…
A Constrained Optimal Model Predictive Control for Mono Inverter Dual Parallel PMSM Drives
2018
The actual trends in the design of AC drives are directed to the reduction of the total weight, volume and cost. Usually, this implies the necessity to adopt new motor topologies and converter architectures. An important role is played by the mono-inverter dual parallel motor (MIDP), which gives the possibility to reduce the total weight and costs of power converters. This paper proposes a novel model predictive control algorithm in order to improve the transient performances of a MIDP used for an overhead carrier. The effectiveness of the proposal control is verified through some numerical simulations.
Regulating feeding and increasing methane yield from co-digestion of C5 molasses and cattle manure
2014
Abstract The paper investigated the mesophilic (∼35 °C) and thermophilic (∼50 °C) co-digestion of cattle manure and C5 molasses for a variable organic loading rate (OLR). The small scale continuous reactor experiment revealed that thermophilic treatment yielded a maximum 313 ± 16 L/kg VS methane for the feeding ranged between 50% and 70% C5 (v/v). Mesophilic co-digestion, on the other hand, produced maximum 232 ± 32 L/kg VS methane when feeding was ranged between 31% and 47% C5 (v/v). The feeding strategy of this study was sophistically adjusted owing to the unstable volatile fatty acids (VFA) pattern, developed at different stages of the experiment. Attainable molasses feeding for both the…
Low-cost smart energy managment based on ATmega 328P-PU microcontroller
2017
This paper presents a real-time, low-cost, wireless, AC and DC monitoring system based on an ATmega328P-PU microcontroller. The proposed system is composed by different client nodes, which have the task to measure the main electrical quantities involved in the system, and a server node that collects the data and send them to a display device. The system is well suited for a good accuracy monitoring of either AC or DC electrical quantities. In order to verify the correct operation of the system, a case study for the simultaneous monitoring of the DC and AC voltages and currents is provided.
Preface of "Life Cycle Assessment of Energy Systems and Sustainable Energy Technologies. The Italian Experience"
2019
This book deals with the application of life cycle assessment (LCA) methodology to sustainable energy systems and technologies. It reviews the state-of-the-art of the Italian experiences on the LCA applied to energy, and the most recent results from research in this field, with a particular focus on renewables, bio-energy and sustainable solutions.