Search results for "Primary energy"
showing 10 items of 45 documents
Energy demand reduction of aluminum alloys recycling through friction stir extrusion processes implementation
2019
Abstract Aluminum alloys are characterized by high-energy demands for primary production. Recycling is a well-documented strategy to lower the environmental impact of light alloys production. Despite that, conventional recycling processes are still energy-intensive with a low energy efficiency. Also, permanent material losses occur during remelting because of oxidation. Recently, several solid-state recycling approaches have been analyzed; in fact, by avoiding the remelting step both energy and material can be saved and, therefore, the embodied energy of secondary production can be substantially reduced. In this paper, the solid-state approach Friction Stir Extrusion (FSE) is analyzed for a…
Friction stir extrusion to recycle aluminum alloys scraps: Energy efficiency characterization
2019
Abstract Solid state recycling refers to a group of processes allowing direct recycling of metals scraps into semi-finished product. Their main advantage lies in avoiding the molten state of the material which badly affects the environmental performance of the conventional (remelting based) recycling routes. It is expected that such process category would lower the environmental performance of metals recycling. In this paper, the friction stir extrusion process for aluminum alloy AA 2050 wire production is analyzed under the primary energy demand perspective. The process electrical energy demand is quantified with varying process parameters. An empirical modelling approach was applied and a…
Uncovering Technological and Environmental Potentials of Aluminum Alloy Scraps Recycling Through Friction Stir Consolidation
2020
Conventional metal chips recycling processes are energy-intensive with low efficiency and permanent material losses during re-melting. Solid state recycling allows direct recycling of metal scraps into semi-finished products. It is expected that this process category would lower the environmental performance of metals recycling. Friction Stir Consolidation is a new solid-state technique taking advantage of friction heat generation and severe plastic deformation to consolidate chips into billets. In this research, the feasibility of Friction Stir Consolidation as aluminum chips recycling process is analyzed. Specifically, an experimental campaign has been carried out with varying main proces…
Integrated WAAM-Subtractive Versus Pure Subtractive Manufacturing Approaches: An Energy Efficiency Comparison
2019
Over the last years, additive manufacturing (AM) has been gathering momentum both in the academic and in the industrial world. Besides the obvious benefits in terms of flexibility and process capabilities, the environmental performance of such processes has still to be properly analyzed. Actually, the advantages of additive manufacturing over conventional processes are not obvious. Indeed, different manufacturing approaches result in different amounts of involved material and in different processing energy demands. Environmental comparative analyses are hence crucial to properly characterize AM processes. In this paper, an energetic comparison between the emerging wire arc additive manufact…
Energy and economic analysis and feasibility of retrofit actions in Italian residential historical buildings
2016
Abstract The application of retrofit actions to existing building stocks can improve the energy performance of the residential sector. In this context, particular attention should be given to historical buildings, which represent a large part of the Italian building stock. To improve the energy performance of them, adequate retrofit actions must be applied. Many studies and regulations have focused on identifying the best refurbishment measures. However, the selection of these measures is difficult due to restrictive regulations, which are dictated by the Ministry of Cultural Heritage and Activities, high retrofit costs, and variable climate zones. Thus, energy renovations in Italian buildi…
Life cycle energy performances and environmental impacts of a prefabricated building module
2018
Abstract The paper explores the energy performances and environmental impacts of a prefabricated building module located in Messina (Sicily, Italy) through an approach that combines both the non-steady state building simulation and the Life Cycle Assessment methodology. The building uses renewable energy technologies and is usable in emergency situations or as simply temporary housing. Results show that the building module causes the emission of 1.5 t of CO2eq/m2 and consumes 29.2 GJ/m2 of primary energy during its life cycle. The building achieves the Net Zero Energy Building target even if it has relevant environmental impacts in the materials production stage (72% on average of the total…
Uses of weeds as an economical alternative to processed wood biomass and fossil fuels
2016
Abstract The use of fossil fuels as a main source of energy is directly linked to global climate change (due to CO2 emission), so there is a necessity to find new, cheap and easily available energy sources for the earth’s inhabitants. Nowadays renewable energy sources are forced also for the mitigation of the effects of climate change as a result of greenhouse gases emission control. Decentralized sources of low-cost renewable fuels that may be used, in particular, in those households where there is no possibility of using gas or heat delivered from other sources should be of special interest. This paper describes the possibility of using untreated plants such as Canadian goldenrod (Solidag…
Energy performance evaluation of a demo solar desiccant cooling system with heat recovery for the regeneration of the adsorption material
2012
Abstract Since July 2008, a Solar Desiccant Evaporative Cooling (DEC) system has been operating as a test plant at the solar laboratory of the Dipartimento di Energia (ex DREAM) of the University of Palermo. The system is composed of an air handling unit (AHU) designed for ventilation of the laboratory coupled with a radiant ceiling that provides most of the required sensible cooling/heating energy. Flat plate collectors deliver part of the regeneration heat of the desiccant wheel during the summertime and are used for space heating during the wintertime. The system was designed for high humidity loads because of the typical climate conditions at the site and the need to support a radiant c…
A methodology for sizing a trigeneration plant in mediterranean areas
2003
Combined heat and power production is an old and well-known technique for the rational use of energy and, thanks to more than fifty years of experience, the state of art can be considered very advanced from a technological point of view. Trigeneration, that is combined electric, heat and cooling energy production, is however a quite recent technology and is becoming economically viable thanks to the commercial spread of absorption chillers. In fact, a well-projected trigeneration plant can achieve better results than a cogenerative one. The CHCP plant benefits over CHP will be underlined, showing the effects of regularisation of annual thermal load curves generated by consumption for feedin…
Energy and economic assessment of desiccant cooling systems coupled with single glazed air and hybrid PV/thermal solar collectors for applications in…
2009
Abstract This paper presents a detailed analysis of the energy and economic performance of desiccant cooling systems (DEC) equipped with both single glazed standard air and hybrid photovoltaic/thermal (PV/t) collectors for applications in hot and humid climates. The use of ‘solar cogeneration’ by means of PV/t hybrid collectors enables the simultaneous production of electricity and heat, which can be directly used by desiccant air handling units, thereby making it possible to achieve very energy savings. The present work shows the results of detailed simulations conducted for a set of desiccant cooling systems operating without any heat storage. System performance was investigated through h…