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Transportation is one of the key sectors causing greenhouse gas (GHG) emissions and air pollution. With the substantial increase in passenger and freight transportation, the corresponding GHG emissions and air pollutants are expected to increase significantly. Recent global and national policies are targeting at reducing environmental impacts of transportation activities. The promotion of public transportation and development of electric buses (e-buses) will reduce the use of fossil fuels in transportation, and consequently, reduce GHG emissions. This study assesses the life cycle GHG emissions and other environmental impacts of e-bus, and compares them with those of conventional bus operated in Vietnam. The results indicate that e-bus is a preferred choice in most of studied environmental impact categories over the whole life cycle such as GHG emission, ozone depletion, ozone formation, fine particulate matter formation, acidification, etc. For GHG emissions, the adoption of electric mobility will reduce 42.62 gCO(2)eq per passenger km of carbon footprint if conventional buses are substituted by e-buses in Vietnam.

Power -to-Gas technologies have been recently introduced as a relevant strategy allowing higher shares of renewable generation in the energy sector

Life Cycle sustainability assessment is one of the most relevant tools delving in sustainability science, based currently on the triple bottom line idea, that is identified in the use of the three tools of Life Cycle Assessment (LCA), Life Cycle Costing (LCC) and Social Life Cycle Assessment (S-LCA). The methodology is structured on international regulations and is currently being applied to a wide set of products and systems. However, when targeting specifically energy technologies with this methodology some specific issues need to be taken in consideration before applying tout court the standard LCSA methodology. Energy systems – in particular those where fluid streams are used – have an understanding depth that cannot be currently investigated with the available tools, thus having only a partial understanding of the problem. This paper proposes to develop an extended framework for LCSA introducing two additional stages to the theory, to address the limits highlighted in the previous paragraphs: Constructal law (CL) inspired analysis of the energy design of the system and exergy analysis (EA) of the system and its life cycle. A fully developed case study (a biomass boiler) is proposed, described in all five stages of the extended Life Cycle Energy Sustainability Assessment: LCA, LCC, S-LCA, CL, EA, highlighting both the quantitative results related to each section and the strengths and limits of the methodology, while stressing the potential applications as e.g. decision support tool and support to the design of energy system. The results highlight different and optimized designs for the boiler through a Constructal law based analysis and several hot-spots throughout different stages of the life cycle, ranging from the production stage of steel for most environmental indicators in LCA to the cooking stage for the exergy analysis. Relevant positive impacts are traced also in the S-LCA point of view during both the use and production step.

The paper presents a Life Cycle Assessment of the energy tri-generation from biomass waste in a plant located in Tunisia. The analysis included the plant construction and end-of-life, the supply of biomass, its use for biogas production and the electricity, heating and cooling generation from biogas. The study is one of the first applications of environmental analysis to tri-generation from biomass waste in developing countries. The results showed that the plant construction is responsible of 76% of primary energy consumption and gives a contribution higher than 88% on resource depletion and ionising radiation. The operation causes 66% of the impact on human toxicity - cancer effects and more than 90% of the other environmental impacts, except for ecotoxicity of freshwater mainly caused during the end-of life. The experience is coherent with the principles of the circular economy and moves toward a cleaner management of waste for energy production

The building sector is one of the key sectors to achieve the 20/20/20 targets of the EU as there is the potential to lead to significant energy savings reducing the EU’s total energy consumption by 5-6% and lowering CO2 emissions by 5%. One powerful mechanism to apply principle and criteria of nearly zero-energy buildings (nZEB). This work, done in the framework of the agreement between the Italian Ministry of Economic development and ENEA on the “Research of electric system” (Ricerca di Sistema Elettrico), has the aim to evaluate the environmental impacts of the technological improvements needed for enhancing the performances of an average building to a nZEB (or at least in the direction of a nZEB), performing a comparative Life Cycle Assessment study. Data on building upgrading and energy consumption reduction come from a test case performed by Università degli Studi di Palermo.

Historic and traditional buildings, including rural ones, are a territorial resource in Europe and constitute an integral part of the European’s cultural heritage. However they are often characterized by poor energy performances and a large potential for energy retrofit actions. On the other hand, the hardest part of retrofitting such buildings is the limited invasiveness that such actions need to have on the historical and heritage value of the building itself. The paper describes an experience of re-design of an existing rural building located in Sicily, inside the ancient Greeks “Valley of the Temples”. An energy audit was performed on the building, its energy uses thoroughly investigated. A building model was developed in TRNSYS environment and its performances validated. The validated model was used for redesign studies aimed towards the improvement of the energy performances of the building in compliance to legislation. The best performing solutions to be applied to a case-study like the Sanfilippo House are those regarding the management of the building, as in the case of the natural ventilation and the HVAC setpoints, that would allow a large impact (up to 10% reductions in energy uses) on the energy performances of the building with no invasiveness, and those with very limited invasiveness and high impact on the energy efficiency of the building, as in the lighting scenario (up to 30% energy uses reduction). The most invasive actions can only be justified in the case of high energy savings as in the case of the insulation of the roof, otherwise should be disregarded.

The paper presents a case-study of a pre-fabricated housing module built in Messina (Sicily, Italy) and the assessment of its energy performances under the net zero energy perspective. The potential of ventilative natural cooling application in the case-study is also investigated. Some particular features of the building - the modularity, the prefabrication, the rapidity of assembly, the possibility of being built on disconnected soils and the absence of maintenance - identify an effective use as a temporary housing solution for e.g. workers in proximity of an isolated working place or in emergency situations such as earthquakes and natural disasters. Monitoring studies were performed during some weeks in summer, the building was simulated in energy plus environment, validated obtaining small and acceptable differences between monitored and simulated data. Results identify the building as a plus zero energy building, with generation nearly doubling the overall electricity consumption. Natural ventilation in the hot Sicilian climate would prove efficient to reduce electricity consumption for cooling by 20% in a year mainly during mid-seasons but the design needs to be improved by including a more bioclimatic-oriented approach.

Il presente studio illustra i risultati ottenuti dall’applicazione della metodologia Life Cycle Assessment (LCA) al Passito di Pantelleria prodotto dall’Azienda vitivinicola “Donnafugata” (Sicilia). L’obiettivo dello studio è quello di quantificare le prestazioni energetico-ambientali connesse al ciclo di vita di una bottiglia di Passito secondo un approccio “from cradle to gate”, nonché le fasi responsabili dei maggiori impatti.

This paper presents a new mathematical approach applied to the Conduction Transfer Functions (CTFs) of a multilayered wall to predict the reliability of building simula- tions based upon them. Such a procedure can be used to develop a decision support system that identifies the best condition to calculate the best CTFs set. This is a critical point at the core of ASHRAE calculation methodology founded on the Transfer Function Method (TFM). To evaluate the perfor- mance of different CTFs sets, the authors built a large amount of data, subsequently employed to train a Neural Network Classifier (NNC) able to predict the reliability of a simulation without performing it. For this purpose all the multilayered walls included in the HVAC ASHRAE Handbook were used, and moreover many other walls typical of Mediterranean building heritage were added. The results show that the proposed method to optimize CTFs based on NNC is highly accurate, fast and easy to integrate in other buildings simulations tools.

Viene presentato uno studio finalizzato alla reda- zione di una Dichiarazione Ambientale di Prodotto (DAP) relativa ad un laterizio porizzato, manufatto edile caratterizzato da buone proprietà termoisolanti e fonoassorbenti. La valutazione delle prestazioni energetico-ambientali del manufatto è stata condot- ta in conformità agli standard internazionali della serie ISO 14040. Sulla base dei risultati dell’analisi sono state individuate alcune soluzioni di migliora- mento dell’eco-profilo del manufatto in esame.

The paper shows a comparative analysis of the performances of two typologies of solar assisted cooling systems for building applications. In particular, Life Cycle Assessment (LCA) methodology is applied to assess the energy and environmental impacts of solar-assisted, heat-driven chillers and conventional compression chillers driven by grid-connected and stand-alone photovoltaic configurations. LCA is applied in compliance with the international standards of ISO 14040. System boundaries are defined following a “cradle to grave” approach, taking into account all the life-cycle phases including the raw materials supply, the production of the components of the plant, the operation and maintenance, and the end-of-life. The operation step of the assessed systems is simulated with TRNSYS models. Two reference buildings are modeled for two different sites, Palermo (Italy) and Rio de Janeiro (Brazil), according to local practices and regulations. The building models are normalized to have the same peak cooling demand (12 kW). The results show that the assessed energy and environmental performances of the grid-connected systems are usually better than the others for both climates, while the manufacturing process of storages in the stand-alone configurations does not allow these solutions to be competitive yet. Furthermore, the impact of the high average national electricity conversion efficiency in Brazil on the results is analyzed and discussed.

The Transfer Function Method (TFM), recommended by American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), is one of the most modern tools available to solve heat transfer problems in building envelopes and environments. TFM utilises Z-transform to solve the equations system that describes the heat transfer in a multi-layered wall. Due to an analogy with an electric circuit, it is possible to write the equations system in a matrix suitable to be solved by computer. Authors carried out an analysis on an historical building placed in the south of Italy to test the reliability and the quality of the thermal dynamic simulation using TFM. The analysis is performed using some control systems tools like Bode plots, step response, root and poles location. Results show clearly that, for very massive building, a simply application of TFM fails but if the poles and the residuals are re-ordered in a different position, it will be possible to solve the numerical problem. Furthermore, the analysis shows that the choice of the sampling period is a significant factor to obtain a reliable simulation.

In this paper a novel dynamic energy performance simulation model for the Phase Change Materials (PCM) analysis is presented. The model is implemented in a suitable computer code, written in MatLab and called DETECt, for complete building energy analyses. In the presented model, the “effective specific heat” method is implemented. Here, the specific heat of each PCM layer changes as a function of the system phase and temperature in both melting and freezing processes. A model validation is carried out by comparing numerical results vs. measurements obtained at Solar Laboratory of Concordia University (Montreal, Canada). The simulation model allows exploring the potential of PCMs to increase the thermal inertia of buildings envelopes and to assess the effects/weight of several design parameters (e.g. PCMs melting temperature, etc.) on the building heating and cooling energy demand and on the related thermal comfort. In order to show the potentiality of the presented simulation model, suitable case studies referred to residential and office buildings, to three different weather conditions and to two alternative PCM layouts in the building envelope, are developed.

The employment of renewable energy sources can represent a useful way to reduce air emissions released by conventional ones. In this paper we describe the results of a Life Cycle Analysis performed upon one of the most world-wide diffused renewable technologies: the solar thermal collectors for warm sanitary water. Two domestic solar plants have been investigated: mono-familiar plant with a passive flat collector and a large solar plant with forced fluid circulation. The first step has been the evaluation of direct and indirect emissions related to the production and use of plants. The main emissions have been categorised in three of the most important indicators (Global Warming Potential, Acidification Potential and Photochemical Ozone Creation Potential) and successively we have estimated the emission saving. Considering that a solar plant works with an auxiliary heater, the pollutants that would be produced by the conventional part of the plant without the employment of collectors are the "emission saving". These avoided atmospheric releases depend on the typology of the used conventional system. The case studies of electric and gas heaters have been investigated. The final aim is to perform a global balance between the air emissions related to the production and use of the solar plants and the emissions saved during their useful-life. These results are synthesised by various indicators that contain useful information to evaluate the environmental efficiency of the studied renewable technology.

The need to collect and process information on urban ecosystem requires the introduction of innovative scientific tools, in order to analyze the current urban factors and to optimize the energetic and environmental profile of urban systems, with regard to carrying capacity and territorial needs and vocations. Addressing these needs requires two main elements: (i) public availability of transparent data; and (ii) availability of interactive software designed to make easier exploration of data, models and results. The aim of the present paper is to show a user-friendly software, which is designed as a decision support system for policy makers in the multi-criteria selection among different planning and management options. Such software is able to assess the whole environmental performance of urban systems and to control the developing trends towards sustainability, in consequence to different scenarios of human management. It can be usefully employed to analyze the developing trends of urban ecosystems and to plan sustainable development strategies, as tool of decision-making support in the selection of the eco-sustainable options.

The initial assessment of electric energy demands of a building is a key element in the design process, that should be integrated in the earlier stages of the design of a net zero energy building. The objective of the study is the creation of predictive models of household electrical consumptions in the Mediterranean/Spanish climate and its implementation in TRNSYS 17 environment. The models offer both a simplified level of analysis, based on average seasonal electrical consumptions trends and a stochastic in-depth level for the simulation of peak loads through the compiling of multiple TRNSYS types.

In the framework of international actions to reduce the energy requirements and greenhouse gases emissions due to buildings, a new International Energy Agency task has been recently established in order to study Net Zero Energy Buildings (NZEBs). The commonly shared concept of NZEB, is a building whose annual balance of energy consumptions tends to zero. This concept is still too imprecise and the authors of this paper participate to the activities of SubTask B of IEA Task40 with the aim of establishing an internationally agreed understanding on NZEBs. The task is based on a common methodology for identifying and refining design approaches and tools to support industry adoption of innovative demand/supply technologies for NZEBS. This goal is pursued through detailed modeling and analysis of specific NZEB case studies. Among the specific objectives of the Sub Task B it is possible to include the analysis of redesigned studies. Redesigned studies should identify better alternative solutions for plants, building envelope or impact on the environment that significantly modify the building. To provide high quality information about the design process of a NZEB, it was decided to examine in detail the specific case study of the Leaf House (LH) located in Ancona, Italy. The studied building is fully monitored in terms of thermal environment, energy production and consumption, water use and occupancy. The purpose of this paper is to present some optionsto improve the performance of the selected building, identified by using the collected data and analyzing a detailed TRNSYS model of plant-building complex. The model has allowed detailed evaluation of the effects of some changes in the design that can improve the behavior of the Leaf House in terms of consumptions of energy resources and environmental impact of the building. The performed analysis shows that the building envelope is already very effective in terms of thermal performance, while the redesign of the thermal plants and the PV system should permit to reach a nearly net zero energy performance.

Surface energy balance of urban areas depends on the thermal features of building materials, as well as the overall urban layout and various anthropogenic factors. In extended urban areas, all these factors give rise to the phenomenon known as Urban Heat Island (UHI). From the point of view of urban health, the occurring of UHI drastically changes the fluid dynamic interaction between the air and the city surface, often preventing the dispersion of gaseous pollutants. In the last years in fact, several studies have monitored the increasing trend of breathing diseases and allergies correlated with the presence of UHI. Nowadays, a rational design of the urban areas within large towns should take into account important factors such as energy requirements, consumption of natural resources, vehicular traffic and air pollution. The study and monitoring of UHI can supply very important data useful to address a correct urban planning policy. At this aim, the authors have created an automatic monitoring system able to acquire weather data in different points of the urban area of Palermo and compare them to the data recorded in a nearby rural area. This paper describes the system setup and the first analyses accomplished with the recorded data.

The IEA EBC Annex 72 focuses on the assessment of the primary energy demand, greenhouse gas emissions and environmental impacts of buildings during production, construction, use (including repair and replacement) and end of life (dismantling), i.e. during the entire life cycle of buildings. In one of its activities, reference buildings (size, materialisation, operational energy demand, etc.) were defined on which the existing national assessment methods are applied using national (if available) databases and (national/regional) approaches. The "be2226" office building in Lustenau, Austria was selected as one of the reference buildings. TU Graz established a BIM model and quantified the amount of building elements as well as construction materials required and the operational energy demand. The building assessment was carried out using the same material and energy demand but applying the LCA approach used in the different countries represented by the participating Annex experts. The results of these assessments are compared in view of identifying major discrepancies. Preliminary findings show that the greenhouse gas emissions per kg of building material differ up to a factor of two and more. Major differences in the building assessments are observed in the transports to the construction site (imports) and the construction activities as well as in the greenhouse gas emissions of the operational energy demand (electricity). The experts document their practical difficulties and how they overcame them. The results of this activity are used to better target harmonisation efforts.

Introduction: The international research project IEA EBC Annex 72 investigates the life cycle related environmental impacts caused by buildings. The project aims inter alia to harmonise LCA approaches on buildings. Methods: To identify major commonalities and discrepancies among national LCA approaches, reference buildings were defined to present and compare the national approaches. A residential high-rise building located in Tianjin, China, was selected as one of the reference buildings. The main construction elements are reinforced concrete shear walls, beams and floor slabs. The building has an energy reference area of 4566 m$^{2}$ and an operational heating energy demand of 250 MJ/m$^{2}$a. An expert team provided information on the quantities of building materials and elements required for the construction, established a BIM model and quantified the operational energy demand. Results: The greenhouse gas emissions and environmental impacts of the building were quantified using 17 country-specific national assessment methods and LCA databases. Comparisons of the results are shown on the level of building elements as well as the complete life cycle of the building. Conclusions: The results of these assessments show that the main differences lie in the LCA background data used, the scope of the assessment and the reference study period applied. Despite the variability in the greenhouse gas emissions determined with the 17 national methods, the individual results are relevant in the respective national context of the method, data, tool and benchmark used. It is important that environmental benchmarks correspond to the particular LCA approach and database of a country in which the benchmark is applied. Furthermore, the results imply to include building technologies as their contribution to the overall environmental impacts is not negligible. Grant support: The authors thank the IEA for its organizational support and the funding organizations in the participating countries for their financial support.