• Energy Research
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Abstract Reaching universal access to electricity by 2030 requires a massive deployment of mini-grids in rural areas of developing countries. Among the many challenges hindering this process, there are the high uncertainties in assessing demand patterns in rural communities, the costs of field survey campaigns, and the absence of ample and reliable datasets coming from existing projects. This paper tries to address these issues by presenting and discussing a database of load profiles from sixty-one off-grid mini-grids from developing countries worldwide, gathered from the literature, private developers and fieldworks, and reported with technical, socio-economic and geographical characterization factors. A clustering procedure led to the identification of five archetypal load profile clusters, which are presented and analyzed together with their load duration curves. Subsequently, the distribution among the clusters of the various characterization factors selected is studied. The proposed approach allows to widen the range of load profiles usually considered, and to seek correlations between the load profile shapes, the peak power and average energy consumption per connection, the number of customers, the age of measurement, geographical position, operator model, type of tariff and generation technologies present. This work establishes a first step in the creation of a shared database for load profiles of rural mini-grids, helping to overcome the lack of available data and difficulties of demand assessment, proposing original insights for researchers to understand load patterns, and contributing to reduce risks and uncertainties for mini-grid developers.

Abstract The primary goal of the project is to design a lighting system that provides the highest visual comfort and conserves energy for different uses and furniture layouts, which considers that the design of the house will be used by many different users. Indoor system designs vary in layout, goals and optics with two levels of intervention: when initially furnished and during daily use. Lighting is managed by a building automation system, which is equipped with motion and daylight sensors and human interfaces with user scenarios. An outdoor design that requires only a standalone system and is powered by photovoltaic and eolic devices has been developed. All systems incorporate LED technology and have been custom-developed for Med in Italy, which resulted in new patents. Lighting system projects have been involved in several competitions, e.g., Med in Italy placed in the Solar Decathlon in Architecture, Electrical Energy Balance, House Functioning, and Sustainability and took third place in the final ranking. Further research developments are in progress and will be seen in next Solar Decathlon Europe in Paris in 2014. This paper describes the project, installation and analyses of the energy savings that the Medinitaly system can achieve compared with traditional solutions. Simulation data are compared with measured data from the period of the Solar Decathlon competition.

Abstract A novel integrated energy system based on a geothermal heat source and a liquefied natural gas heat sink is proposed in this study for providing heating, cooling, electricity power, and drinking water simultaneously. The arrangement is a cascade incorporating a flash-binary geothermal system, a regenerative organic Rankine cycle, a simple organic Rankine cycle, a vapor compression refrigeration cycle, a regasification unit, and a reverse osmosis desalination system. Energy, exergy, and exergoeconomic methods are employed to analyze the suggested system. A parametric study based on decision variables is carried out to better assess the system performance. Four different multi-objective optimization problems are also carried out. At the most excellent trade-off solution specified by the TOPSIS method, the system attains 29.15% exergy efficiency and 1.512 $/GJ total product cost per exergy unit. The main output products are consequently calculated to be 101.07 kg/s cooling water, 570.44 kW net output power, and 81.57 kg/s potable water.

Abstract Increasing electrification of final uses can be a viable solution towards low-carbon energy systems, when coupled with local renewable power generation. Mountain areas can already benefit from high shares of hydro-power generation, but, at the same time, rely on oil products for transport and for the heating sector in remote areas where natural gas infrastructures are not available. This research work evaluates potential scenarios for the electrification of transport and heating sectors, by coupling the simulation tool EnergyPLAN with a multi-objective optimization algorithm to analyse economic and environmental aspects. Results show that the largest benefits are expected from the electrification of the heating sector. Indeed, a CO2 emissions reduction up to 30% can be reached by acting on the transport sector alone, while up to 65% combining it with measures on heating, industry and agriculture sectors and additional electricity generation from photovoltaic systems. Moreover, the use of heat pumps can lead to significant CO2 emissions decrease with only to a slight increase in the overall annual costs thanks to lower variable costs that partly compensate the higher required initial investment and electricity storage deployment. The optimization analyses also highlight the effect of progressive penetration of electric vehicles in the private cars fleet and hydrogen trucks in the light-duty vehicles one.

Disproportionation of superoxide to peroxide and O2 generates the highly reactive singlet O2, which needs to be avoided for highly reversible metal–O2 batteries.

The average antimony concentration in municipal solid waste is estimated to be about 10-60 ppm. Thermodynamical models predict a volatile behavior for antimony compounds, yet literature mass balances show that about 50% of the antimony input remains in the grate ashes. This fact can be explained by the formation of thermally stable antimonates in the fuel bed due to interactions with alkali or earth-alkali metals. Thermogravimetric experiments revealed an increased thermal stability for antimony oxide in presence of oxygen and calcium oxide. Spiking experiments on the test incinerator TAMARA showed that chlorination processes have a strong effect on antimony volatilization whereas high fuel-bed temperatures and addition of antimony oxide only have a moderate effect. In the grate ashes, antimony shows a pH-depending leaching property, which is typical for anionic species. This fact supports the thesis that antimony is present in the grate ashes in an anionic speciation.

AbstractRecently, great attention has been given to the transition from centralized to distributed generation energy production systems. There is a growing potential regarding the use of trigeneration systems in the residential sector because they have the ability to produce thermal energy and electricity from a single source of fuel.This study has the goal to determine the best systems able to satisfy the demand for electricity and thermal energy for a complex of historic buildings in Rome. Such analysis has been conducted using a specific tool conceived for energetic and financial analysis: the RETScreen software.

Annually, 115.000 tons of plastic tableware are used in Italy. The end of life of these objects is particularly troubled because no efficient way of recycling or reusing exist. Studies performed by the European Union demonstrate that about 80% of sea waste is made of plastic, representing a danger to human health and ecosystem. The aim of this paper is to analyse substitutes to disposable plastic tableware using the Life Cycle Assessment methodology. The alternatives are objects made of bio compostable plastic, both disposable and reusable. This article compares single-use and multi-use tableware made of a Polylactic acid (PLA) - Polybutylene succinate (PBS) blend with traditional disposable tableware made of polypropylene and of polystyrene. In order to perform an effective assessment, the objects are grouped in place settings, each made of a cup, a plate and cutlery. The use of tray mat and napkin is also taken into account. It was assumed that the fossil-based items are sent to landfill whereas the bio-based ones are sent to a compost plant. The functional unit chosen was “the service of 1000 meals”. The impact categories taken into account are Global Warming 100a, Ozone Depletion, Ozone Formation (Vegetation), Acidification, Aquatic Eutrophication, Human Toxicity water and Ecotoxicity water chronic. The results show that the compostable table sets have lower impact than the sets made of fossil-based plastic in all the categories except in Ozone Depletion and in Aquatic Eutrophication. In the categories of Human Toxicity water and Ecotoxicity water chronic, fossil-based materials have higher impact than multi-use one mainly due to the landfill scenario chosen as end of life. Disposable and reusable systems give a different contribution to total impact in different life stages. For disposable systems, the production and the end of life are the critical stages in terms of environmental burden, whereas for reusable systems washing is the most impactful phase. Further improvements can be obtained in the production of bio-based materials by using renewable energy to power the facilities whereas the washing phase can be improved by adopting certified ecopower. The impact of the reusable system strongly depends on the assumptions made on the number of reuses and on the washing modality.