Search results for "electric [charge]"
showing 10 items of 729 documents
Design, assembly and characterization of silicide-based thermoelectric modules
2016
ID: 1143 In: Energy conversion and management, 13-21. Summary: Highlights•Novel silicide-based thermoelectric modules were experimentally investigated.•The modules produced high power of 1.04 W at 405 °C and 3.24 W at 735 °C.•An estimated module efficiency of 5.3% represent the highest reported for silicide systems.AbstractSilicides have attracted considerable attention for use in thermoelectric generators due mainly to low cost, low toxicity and light weight, in contrast to conventional materials such as bismuth and lead telluride. Most reported work has focused on optimizing the materials properties while little has been done on module testing. In this work we have designed and tested mod…
A set of indicators for arc faults detection based on low frequency harmonic analysis
2016
In this paper a novel set of indicators is presented for arc faults detection in electrical circuits. The indicators are defined starting from an experimental characterization of the arc fault phenomenon and the study of the arcing current in several test conditions, which were chosen in accordance with the UL 1699 Standard requirements. The proposed parameters are measured by means of a high resolution low frequency spectral analysis of the arcing current, which allows to achieve a good spectral resolution even with short observation windows.
Assessing the feasibility of cogeneration retrofit and district heating/cooling networks in small Italian islands
2017
Sustainability of energy supply strategies in small islands has been emerging as a severe issue, due to the large margins for improvement and rationalization of the most frequently adopted solutions. In most of the European islands, large amounts of heat are wasted by the operation of engine-based power plants; conversely, heat is produced by boilers (supplied by liquid fuels) or by electric equipment for a number of different uses, like domestic hot water production or space heating in winter. In this paper a techno-economic analysis is proposed to assess the feasibility of CHP-retrofit of the existing power plants and the possible utilization of the recovered heat to supply, via a distric…
An Adaptive Robust Predictive Current Control for Three-Phase Grid-Connected Inverters
2011
This paper presents an adaptive robust predictive current control (RPCC) for grid-connected three-phase inverters that exhibit zero steady-state current error. The error correction is achieved by means of an adaptive strategy that works in parallel with the deadbeat algorithm, therefore preserving the typical fast response of the predictive law. The resulting control adapts to any particular L or LCL filter by estimation of the resistive part of the filter. As a variety of the RPCC class of control, it offers the best tradeoff between robustness and speed. © 2009 IEEE.
Numerical Analysis of Piezoelectric Active Repair in the Presence of Frictional Contact Conditions
2013
The increasing development of smart materials, such as piezoelectric and shape memory alloys, has opened new opportunities for improving repair techniques. Particularly, active repairs, based on the converse piezoelectric effect, can increase the life of a structure by reducing the crack opening. A deep characterization of the electromechanical behavior of delaminated composite structures, actively repaired by piezoelectric patches, can be achieved by considering the adhesive layer between the host structure and the repair and by taking into account the frictional contact between the crack surfaces. In this paper, Boundary Element (BE) analyses performed on delaminated composite structures …
Transient stability analysis for symmetrical and unsymmetrical faults in mixed three-phase and six-phase power systems
1989
Abstract The aim of this paper is to analyse the transient stability of a three-phase power system with six-phase lines interconnected by three-phase to six-phase transformers. For these mixed power systems a transient stability analysis is performed under all main types of disturbances (short-circuits, generator and load rejection, line outages), particularly in the case of faults at six-phase buses. A generalized procedure to evaluate transient stability is explained in detail. It is based on the symmetrical components method, which allows one to consider also unsymmetrical faults both at three-phase and six-phase buses. For every possible unsymmetrical short-circuit an equivalent fault a…
Quasi-digital conversion for resistive devices: application in GMR-based IC current sensors
2013
Resistive devices, including sensors, are used in a huge range of applications within different scenarios. When a complete system is considered, a quasi-digital output is often recommendable. If the conversion is operated at device level, some problems such as noise disturbs, insertion losses and so on, can be reduced. In this work, we describe a resistance-tofrequency (R-f) converter with a suggested application in low current monitoring by means of GiantMagnetoResistance (GMR) sensors. Specific devices have been designed and microfabricated. The system has been tested by means of discrete components with a PCB. The complete microsystem monolithic integration in a standard CMOS technology …
Embodied energy and environmental impacts of a biomass boiler: a life cycle approach
2015
The 2030 policy framework for climate and energy, proposed by the European Commission, aims towards the reduction of European greenhouse gas emissions by 40% in comparison to the 1990 level and to increase the share of renewable energy of at least the 27% of the European's energy consumption of 2030. The use of biomass as sustainable and renewable energy source may be a viable tool for achieving the above goals. However, renewable energy technologies are not totally clean because they cause energy and environmental impacts during their life cycle, and in particular they are responsible of air pollutant emissions. In this context, the paper assesses the energy and environmental impacts of a …
Experimental Study of Cross-flow Micro-turbines for Aqueduct Energy Recovery
2014
An important component of the management cost of aqueducts is given by the energy costs. Part of these costs can be recovered by transforming some of the many existing energy dissipations in electric energy by means of economic turbines. In this study an experimental work has been carried out: 1) to test the performance of an economic Cross-Flow turbine which maintains high efficiency within a large range of water discharges, and 2) to validate a new approximated formula relating main inlet velocity to inlet pressure. It is proved that the proposed formula, according to some simplifying assumption, exactly links inlet velocity to inlet pressure according to any possible geometry of the Cros…
Piezoelectric energy harvesting from raised crosswalk devices
2015
This paper presents the main characteristics of an experimental energy harvesting device that can be used to recover energy from the vehicular and pedestrian traffic. The use of a piezoelectric bender devices leads to a innovative approach to Henergy Harvesting. The study focuses on the definition and specification of a mechanical configuration able to transfer the vibration from the main box to the piezoelectric transducer. The piezoelectric devices tested is the commonly used monolithic piezoceramic material lead-zirconate-titanate (PZT). The experimental results estimate the efficiency of this device tested and identify the feasibility of their use in real world applications. The results…