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The surface albedo in urban environment represents one of the most influencing parameters in the formation of the Urban Heat Island (UHI). Its assessment is therefore strategic to undertake actions for the UHI mitigation: the increase of urban surface reflectivity is an example of cooling strategies increasingly proposed and developed. Spaceborne observations could give a significant contribution supplying albedo maps, and different retrieval algorithms estimating broadband albedo from narrow band reflectivities provided by satellite sensors were proposed and validated in literature. In this study, the accuracy of two well-known retrieval algorithms applied to Landsat 8 OLI reflectivities was assessed in a city of Central Italy (Perugia), selecting test sites having different land cover types. Since the root mean square error of the estimated albedo was quite high (0.07–0.08), a custom retrieval algorithm was developed to evaluate the potential improvement in the narrowband reflectivity-broadband albedo conversion for the case study. This analysis was made possible thanks to an in situ measurement campaign, carried out during the summer months of 2016. The selected sites, having quite homogenous features inside the urban environment, also demonstrated that the albedo values are not significantly affected by the hour of the day, if measurements are taken near noon (variation less than 7%). Spaceborne observations showed once again a powerful tool for monitoring large areas with a quite good spatial resolution (30 m), even if an improvement of the literature albedo retrieval algorithms is required and possible in an urban context. [ABSTRACT FROM PUBLISHER]

The paper presents recent and future trends of the world energy market, as highlighted by medium- and long-term projections. Energy demand and energy consumptions projected by IEA (International Energy Agency) are examined, in comparison with projections provided by other international agencies and companies in the energy sector. In particular, energy resources, energy consumption and economic growth both in developing and developed countries are presented, with a particular attention to the role of energy efficiency, nuclear power, unconventional fossil resources and renewable energies. Sustainable development issues, according to the global climate agreement signed at COP21, are also presented. The outlook period extends up to 2040. The results confirm a worldwide interest in renewable and unconventional resources for the forthcoming decades, as well as efforts to increase the energy efficiency potential in all end-use sectors to reduce the overall environmental impact of energy production. [ABSTRACT FROM AUTHOR]

Household energy consumption has been increasing in the last decades; the residential sector is responsible for about 40% of the total final energy use in Europe. Energy efficiency measures can both reduce energy needs of buildings and energy-related CO2 emissions. For this reason, in recent years, the European Union has been making efforts to enhance energy saving in buildings by introducing various policies and strategies; in this context, a common methodology was developed to assess and to certify energy performance of buildings. The positive effects obtained by energy efficiency measures need to be verified, but measuring and monitoring building energy performance is time consuming and financially demanding. Alternatively, energy efficiency can also be evaluated by specific indicators based on energy consumption. In this work, a methodology to investigate the level of energy efficiency reached in the Umbria Region (Central Italy) is described, based on data collected by energy certificates. In fact, energy certificates, which are the outcomes of simulation models, represent a useful and available tool to collect data related to the energy use of dwellings. A database of building energy performance was developed, in which about 6500 energy certificates of residential buildings supplied by Umbria region were inserted. On the basis of this data collection, average energy and CO2 indicators related to the building heritage in Umbria were estimated and compared to national and international indicators derived from official sources. Results showed that the adopted methodology in this work can be an alternative method for the evaluation of energy indicators; in fact, the ones calculated considering simulation data were similar to the ones reported in national and international sources. This allowed to validate the adopted methodology and the efficiency of European policies. [ABSTRACT FROM AUTHOR]

Biodiesel is obtained by the process of transesterification of vegetable oils and animal fats and crude glycerol is the main by-product of the biodiesel manufacturing chain. As a result glycerol production has rapidly increased in the last decades. This work focuses on the development and the validation of a process to convert biodiesel-derived glycerol into a fuel for internal combustion engines. In order to obtain a higher conversion efficiency it was necessary to convert crude glycerol to tert-butyl ethers by means of an etherification process that was carried out in the laboratory. Then the obtained glycol-ethers mixture (GEM) was blended with a commercial diesel fuel to improve its thermal efficiency. In this paper a life cycle analysis for these GEM/diesel blends was carried out using a Life Cycle Assessment (LCA) methodology, in order to evaluate the environmental impacts of these new oxy-fuels; from GEM production to GEM use as an additive for diesel fuel. The LCA results highlight that the use of these new oxy-fuels in diesel engines can lead to an effective reduction in terms of greenhouse gases emissions throughout the entire life cycle. [ABSTRACT FROM AUTHOR]

The evaluation of the overall performance of a green building is complex, since many construction, energy and environmental aspects have to be considered. The Umbria Region in Italy, through various public tenders, recently funded several residential buildings, innovative in terms of construction quality, green technologies and sustainable solutions, such as natural building materials, integrated sunspaces, PV (photovoltaic) modules and solar collectors, geothermal heat pumps, that had to be adopted to obtain the public contribution. The University of Perugia carried out an extended monitoring of these buildings, in order to verify the actual achievement of design objectives, to certify the real savings in terms of energy and environmental loads and to assess the indoor comfort conditions for occupants. In situ thermal, acoustical and lighting measurements were carried out for more than one year. Energy simulations were performed by means of codes which implement the algorithms required by the Italian Law. Moreover, a comparison between real consumptions and simulated energy requirements was carried out. Finally, the buildings were characterized from the environmental sustainability point of view, using the method adopted by the Umbria Region. This assessment was borrowed from ITACA (Institute for Innovation and Transparency in Government Procurement and Environmental Compatibility) procedure [an Italian procedure similar to Leadership in Energy and Environmental Design (LEED)] and consists of 20 worksheets, one for each different performance indicator, at the aim of carefully describing the environmental quality of the building. [ABSTRACT FROM AUTHOR]

In recent years, ventilation of indoor environment became relevant in the design of well-insulated buildings; with the aim of fulfilling energy saving requirements, new building mechanical ventilation systems have been developed to guarantee heat recovery. The most common heat recovery systems used in air conditioning systems permit only heat recovery, without moisture exchange. However, exchangers capable to recover heat and mass have been developed in the latest years, i.e. the enthalpy exchangers, which use porous materials or membranes. These materials allow the transfer of water vapor molecules between inlet and outlet air. In the present paper the performance of an original and innovative organic polymeric membrane was analysed and compared to a commercial one. The effectiveness of the two membranes was tested by a single plate enthalpy exchanger developed for this purpose, looking at the ability of each membrane to transfer heat and moisture between two airstreams, varying their temperature and relative humidity. Results shows that both membranes have similar performance in terms of moisture transfer between the two airstreams, confirming that the proposed membrane could play a role in the world of the enthalpy exchangers, considering its lower production cost. • An innovative membrane is developed for air enthalpy exchangers. • An experimental air enthalpy exchanger has been especially built for this purpose. • The latent and sensible effectiveness of an innovative and a commercial membrane one was analysed and compared. • The innovative membrane shows itself suitable to be used in energy recovery systems. [ABSTRACT FROM AUTHOR]