Search results for "jel:Q"
showing 10 items of 71 documents
Analytical Investigation and Control System Set-up of Medium Scale PV Plants for Power Flow Management
2012
In the field of photovoltaic (PV) plants and energy conversion from renewable sources, a large part of the technical literature is more devoted to practical aspects (new solar cells, electrically driven PV panels, safety, reduction of parasitic currents, etc.) than to theoretical investigations. Despite this tendency, this paper presents a mathematical analysis of a medium scale photovoltaic power generation system connected to the distribution network and of its control system. In such a system, the conversion stage is unique due to the absence of a boost chopper. The conducted analysis leads to the interesting conclusion that the inverter used in the plant presents two degrees of freedom,…
Proof of Concept of an Irradiance Estimation System for Reconfigurable Photovoltaic Arrays
2015
In order to reduce the mismatch effect caused by non-uniform shadows in PV arrays, reconfigurable interconnections approaches have been recently proposed in the literature. These systems usually require the knowledge of the solar radiation affecting every solar module. The aim of this work is to evaluate the effectiveness of three irradiance estimation approaches in order to define which can be well suited for reconfigurable PV arrays. It is presented a real-time solar irradiance estimation device (IrradEst), implementing the three different estimation methods. The proposed system is based on mathematical models of PV modules enabling to estimate irradiation values by sensing a combination …
Evaluation of the Water Scarcity Energy Cost for Users
2013
Abstract: In systems experiencing water scarcity and consequent intermittent supply, users often adopt private tanks that collect water during service periods and supply users when the service is not available. The tank may be fed by gravity or by private pumping stations depending on the network pressure level. Once water resources are collected, the tank can supply users by gravity if it is located on the rooftop or by additional pumping if underground. Private tanks thus increase the energy cost of the water supply service for users by introducing several small pumping structures inside the network. The present paper aims to evaluate this users’ energy cost for different private tank con…
Slotted Blades Savonius Wind Turbine Analysis by CFD
2013
In this paper a new bucket configuration for a Savonius wind generator is proposed. Numerical analyses are performed to estimate the performances of the proposed configuration by means of the commercial code COMSOL Multiphysics® with respect to Savonius wind turbine with overlap only. Parametric analyses are performed, for a fixed overlap ratio, by varying the slot position; the results show that for slot positioned near the blade root, the Savonius rotor improves performances at low tip speed ratio, evidencing a better starting torque. This circumstance is confirmed by static analyses performed on the slotted blades in order to investigate the starting characteristic of the proposed Savoni…
Strategic Vision of a Euro-Mediterranean Port City: A Case Study of Palermo
2013
Italian harbours assume a decisive role in order to develop a Euro-Mediterranean web for maritime transportation. The geostrategic position of the Italian peninsula can be seen as a logistic platform at the centre of the maritime trades in the Mediterranean area, giving to its port cities the role of gateway of economic flows. The port poles, meant as hubs, are able to attract investments and create economic growth and territorial development through new operative models of urban usage and management. The management policies have to consider the environmental characteristics and distinctive features, respecting the identity of the places as concrete evidence of history, a source of intellec…
Evaluating the Sustainability in Complex Agri-Food Systems: The SAEMETH Framework
2015
During the last few years, the definition of sustainability and the translation of its general principles into practical and operative tasks have come into the foreground of scientific research and political agendas throughout the world. The understanding and the evaluation of the environmental, social and economic performances of complex agricultural food systems is probably the real challenge, and the design of more sustainable alternatives has been recognized as necessary for a correct territorial management. This study’s primary goal is the proposition of an interpretive structure “Sustainable Agri-Food Evaluation Methodology” (SAEMETH), able to guide the evaluation of the sustainabilit…
Improving the sustainability of transportation: environmental and functional benefits of right-turn by pass lanes at roundabouts
2015
The functional performances of conventional roundabouts (single-lane and multi-lane) and innovative roundabouts (spiral, flower, C and turbo) can be improved through right-turn bypass lanes controlled by stop, yield or free-flow signs. The article presents evaluations of the emissions of air pollutants (carbon dioxide, nitrogen oxides, particle pollution (PM10 and PM2.5)), fuel consumption and construction, management, energetic and environmental costs in roundabouts without or with bypass lanes (controlled by stop, yield or free-flow). The suggested methodology has a general character and can be applied as a multi-parametric criterion for choosing road intersections, although, in the prese…
Post Feed-in Scheme Photovoltaic System Feasibility Evaluation in Italy: Sicilian Case Studies
2014
: Thanks to national energy policies, over recent years the Italian photovoltaic (PV) sector has undergone an extraordinary growth, also affecting the primary sector. In this context, Mediterranean greenhouses are well-adapted to photovoltaic systems because they represent one of the most energy-intensive sectors in agriculture. The Italian feed-in scheme ended at the beginning of 2013, making it necessary to investigate the feasibility of photovoltaic systems devoid of any electricity production-related incentives. In this paper, production cost and profitability analyses of photovoltaic electricity have been conducted, considering Mediterranean solar greenhouses in which, thanks to net me…
Pollution and economic growth: a maximum likelihood estimation of environmental Kuznets curve
2011
As in Brock and Taylor (2011) in this paper we consider the importance of the relationship between the Environmental Kuznets Curve (EKC) Literature and the Economic Growth Theories. To address this issue we construct country production functions that directly incorporate CO2 emissions as input and estimate them using Stochastic Frontiers. This approach differs from that of Brock and Taylor (2011) but is similar to the one followed by Koop (1998). By introducing the environmental “bads” directly in the production function, we can analyse their contribution to total output growth. We highlight an important contribution of CO2 emissions to growth and find out that the EKC seems not to hold, at…
Thermoeconomic optimization of a renewable polygeneration system serving a small isolated community
2015
During the last years, special attention has been paid to renewable polygeneration technologies, able of simultaneously producing thermal, cooling, electrical energy and desalinated water from seawater. This paper focuses on an innovative polygeneration system driven by renewable energy sources, including the following technologies: hybrid photovoltaic/thermal collectors, concentrating parabolic trough (CPVT), a biomass heater, a single-stage absorption chiller and a multiple-effect distillation desalination system. The system is designed to cover the base load of an isolated small community. In previous papers, the dynamic simulation model about plant operation is discussed. In this paper,…