Search results for "Energy efficiency"
showing 10 items of 177 documents
Energy consumption and improvement of energy efficiency for the European agricultural-food system
2020
This work addresses the subjects of reducing fossil energy consumption and the interventions to improve energy efficiency in the European agricultural-food sys-tem. Following an overview on both such subjects, the results of European projects TESLA and SCOoPE are also analysed with attention to best practices and technologies available to improve energy efficiency in order to reduce the fossil energy use in agri-food systems of Mediterranean countries. A list of Key Performance Indicators for the fruit and vegetable sector, useful for comparative analyses aimed at selecting best methods of energy management and technologies for improving energy efficiency, is reported. Finally, a brief focu…
DC/DC converter topologies for electrolyzers: State-of-the-art and remaining key issues.
2017
In recent years, the use of electrolyzers to produce cleanly and efficiently hydrogen from renewable energy sources (i.e. wind turbines, photovoltaic) has taken advantage of a growing interest from researchers and industrial. Similarly to fuel cells, DC/DC converters are needed to interface the DC bus with the electrolyzer. Usually, electrolyzers require a low DC voltage to produce hydrogen from water. For this reason, a DC/DC buck converter is generally used for this purpose. However, other DC/DC converter topologies can be used depending on the feature of the electrolyzer and electrical grid as well. The main purpose of this paper is to present the current state-of-the-art of DC/DC conver…
Improving the energy efficiency of an islanded distribution network using classical and innovative computation methods
2016
The paper presents the analysis of some potentially suitable actions for reducing the energy losses of an islanded Medium Voltage distribution network, with the aim of improving electricity distribution efficiency. For this purpose, four actions are considered: 1) increasing the network's rated voltage; 2) reactive power compensation through static capacitor banks; 3) reactive power compensation through switchable capacitor banks; 4) installation of distributed photovoltaic (PV) generation. The first two measures are typically taken into account by the distribution system operators and can be examined by means of classical design methods, whereas the latter two more innovative actions are t…
Energy Efficient Scheduling in Content Distribution Collaborative Mobile Clusters
2020
Most of the existing literatures on green communications aimed to improve the energy efficiency at the base station or data server. However, in order to fully experience high rate broadband multimedia services, prolonging the battery life of user equipment is also critical for the mobile terminals, especially for the smartphone users. In this work, we investigate the problem of designing a content distribution mobile platform named collaborative mobile clusters (CMC) via user cooperation to reduce the energy consumption at the terminal side. Specifically, given numbers of users interested in downloading a common content from the operator, both centralized and distributed user grouping and s…
Extraction of thermal characteristics of surrounding geological layers of a geothermal heat exchanger by 3D numerical simulations
2016
Ground thermal conductivity and borehole thermal resistance are key parameters for the design of closed Ground-Source Heat Pump (GSHP) systems. The standard method to determine these parameters is the Thermal Response Test (TRT). This test analyses the ground thermal response to a constant heat power injection or extraction by measuring inlet and outlet temperatures of the fluid at the top of the borehole heat exchanger. These data are commonly evaluated by models considering the ground being homogeneous and isotropic. This approach estimates an effective ground thermal conductivity representing an average of the thermal conductivity of the different layers crossed by perforation. In order …
Efficiency improvement of a ground coupled heat pump system from energy management
2011
The installed capacity of an air conditioning system is usually higher than the average cooling or heating demand along the year. So, most of the time, the system is working under its actual capacity. In this contribution, we study the way to improve the efficiency of a ground coupled heat pump air conditioning system by adapting its produced thermal energy to the actual thermal demand. For this purpose, an air conditioning system composed by a ground coupled heat pump and a central fan coil linked to an office located in a cooling dominated area was simulated, and a new management strategy aiming to diminish electrical consumption was developed under the basic constraint that comfort requi…
Il miglioramento energetico nel recupero degli edifici storici. Applicazione al patrimonio architettonico palermitano
L'architettura storica può assumere un ruolo rilevante nel raggiungimento degli obiettivi europei di efficienza energetica per il settore edile, obiettivi che, tuttavia, devono essere compatibili con la conservazione del patrimonio storico e del suo valore culturale. A tal fine è necessario far riferimento ai caratteri specifici dell'architettura storica e alla sua dimensione locale. La presente tesi, sulla base di tale assunto, esamina le prestazioni energetiche degli edifici storici e il loro potenziale miglioramento, concentrandosi sul patrimonio architettonico di Palermo, caso di studio significativo per l'area mediterranea. La ricerca, condotta con riferimento sia alla scala urbana sia…
Energy retrofit actions on Italian historical buildings: energy efficiency and feasibility. A review study.
2016
Today in EU, the growth in global primary energy consumption is decreasing. In 2014, Italy contributed with a global reduction of 17.1%, thanks to the application of EU measures on different areas. However, there is still much work to be done in order to make sustainable societies and territories, especially in buildings sector that has the greatest potentiality of energy saving. In particular, in the framework of Conservation, Restoration, Refurbishment, and Retrofit actions, the debate is still open, because many aspects must be considered and solved yet. In this paper, the state of the art of the Italian residential building heritage has been reviewed, applicable energy retrofit issues a…
Energy efficiency analysis in Incremental Sheet Forming operations
2012
In literature, manufacturing processes have been studied with different approaches, but a lack in terms of their environmental impact and energy required is still present. The aim of this paper is to compute some energy efficiency analysis on a specific manufacturing process. More in detail, the attention will be focused on the Incremental Sheet Forming process in order to evaluate the required energy and how it changes for changing process conditions. Accordingly, a wide experimental investigation has been executed taking into account different process parameters (i.e. tool depth step, punch diameter, wall inclination angle and sheet thickness). The total energy consumption has been monito…
Sustainable technologies for greenhouse systems
2020
The greenhouse cultivation system in European countries represents one of the most energy-intensive sectors in the agriculture and agro-industry sector. In this regard, renewable energies represent an innovative solution to reduce energy costs and environmental impacts. Both, the energy demands and the economic aspects are analyzed with regard to the main energy users, i.e.: heating and cooling systems, lighting and pumping for irrigation. This work considers the use of solar photovoltaic and thermal energy. The use of semi-closed greenhouses is also considered.