Search results for "Off"
showing 10 items of 2973 documents
Annual heating energy requirements of office buildings in a European climate
2016
Abstract The concept of implementing energy savings to reduce greenhouse gas emissions has become a key element of energy policies of any industrialized country. In the civil sector and specifically, energy savings for office buildings, there are still opportunities for further enhancements related to correctly determining the air conditioning thermal requirements. However, there is a lack of simple correlations that allow a preliminary assessment for a single building or correlations that can be quickly applied at the district level. This paper proposes several simple correlations that determine the heating loads of a typical office building by only knowing the Degree-Days of a specific Eu…
Small Wind Technology Diffusion in Suburban Areas of Sicily
2015
Among renewable energy resources, wind energy became more attractive in the last decade. Wind farm installations dramatically increased in areas where climatic conditions, topography, and environment have allowed their development. The installation of wind turbines, usually carried out in remote areas, recently began to cover areas identified by a complex terrain such as urban and suburban zones. Although these new plant choices are characterized by lower productivity, there is increasing interest in wind energy production in both urban and suburban areas. In this work the authors have carried out an energy analysis developed from a sample of small wind turbines available on the market. Thi…
Design, fabrication, and analysis of a spin-valve based current sensor
2004
Abstract In this work, we suggest a novel current sensor design, based on spin valve technology, with a full Wheatstone bridge configuration. The principal characteristic is that the four magnetoresistance sensing elements, fully active, are deposited and patterned at the same time. This way, differences among them should be insignificant, so improving voltage offset and drift temperature parameters. The complete IC fabrication process involves only three lithography steps, making the process cheaper and faster. In order to get a balanced bridge, the measured current must be properly driven, by means of an auxiliary PCB. Some prototypes, with different input impedances, have been fabricated…
Using semantics to facilitate data integration of offshore wind farms
2012
Operation and maintenance play an important role in extracting power from the wind, especially, in offshore wind energy where wind farms are located far off the shore and under harsh weather conditions. Improved operation and maintenance is likely to reduce costs as well as hazard exposure of the employees. Implementation of advanced information technology is thus crucial for operating offshore wind farms effectively and efficiently and hence improves operation and maintenance. However, information availability and reliability are key issues for their use in the offshore wind domain. In addition, the semantic of information has not been exploited thoroughly. This paper describes the develop…
Assessment of the technical and economic potential of offshore wind energy via a GIS application: A case study for the Sicily Region according to Ita…
2015
This paper presents a technical and economic analysis of the possible exploitation of offshore wind resources using spatial analysis methods based on GIS tools. The study assessed the magnitude and distribution of the main constraints on installation of wind farms by taking into account the relevant technical factors and local laws on nature protection issues in a specific area, i.e., Sicily. Specific cost functions were defined for several components of the total cost of construction and maintenance of a wind farm. Several scenarios were implemented according to wind turbine size, hub height, total wind farm power, and distance from the coast, and the levelised production cost was assessed…
A two-stage fault detection and classification for electric pitch drives in offshore wind farms using support vector machine
2017
This article presents a two-stage fault detection and classification scheme, for induction motor drives in wind turbine pitch systems. The presented approach is suitable for application in offshore wind farms. The adopted strategy utilizes three phase motor current sensing at the pitch drives for fault detection and only when a fault is detected at this stage, features extracted from the current signals are transmitted to a central support vector machine classifier. The proposed method is validated in a laboratory setup of the pitch drive.
Wind Turbines to Power Telecommunication Systems: A Case Study in Sicily
2011
The ever increasing problems related to air pollution and the difficulties for power lines to reach inaccessible areas are pushing to find new solutions for powering telecommunications equipments (TLC). The renewable energy sys- tems, although relatively expensive, have the required characteristics. The purpose of this work is to find a solution based on a low power wind turbine to serve a real telecommunication site located near Palermo, the main city of Sicily (Italy).
Impact of Building Layouts on Wind Turbine Power Output in the Built Environment: A Case Study of Tsu City
2014
In city planning, it is important to consider the future growth of renewable energy systems in the built environment. Wind speed analysis in the built environment is very important for analysing the wind turbine performance installed in the built environment. In this work, building topologies / layouts in Tsu city are considered for investing the wind speed distributions and directions. Wind speed profile in the built environment are developed by using CFD-ACE+. This work focusses on the analysis of the wind speed directions and distribution characteristics for finding out the proper location of the wind turbines in the built environment. The wind speed profiles and their directions and win…
On the sway stability improvement of car–caravan systems by articulated connections
2015
The present analysis is addressed to some promising connection arrangements between the towing vehicles and the towed trailers, where the two units are linked by four-bar isosceles trapeziums in place of the conventional pintle hitch. Two types of instability, of the divergent type or the oscillating type, may be analysed by the Routh–Hurwitz criterion or by the direct analysis of the characteristic equation. The constant term of this equation vanishes at the divergent instability threshold (zero of a real root), whereas the equation splits into two lower degree algebraic ‘sub-equations’ when the oscillating instability arises (pair of pure imaginary roots). A large field of geometrical con…
Guarding, guiding, gate opening: Prison officer work in a Norwegian welfare context
2017
Anne A is a prison officer, and for years, she has been working behind the walls—in low-security and high-security wings, with remand and sentenced prisoners. She says: We are there fifty per cent in order to keep an eye on them, to ensure that they stay here [in prison]. The other fifty per cent we are trying to help them. They may be drug users or have other problems, and it’s just as much our duty to help them as to watch them. And when we help, this contributes to security just as much as a locked door or an alarm.