73 research outputs found
Building stock simulation to support the development of a district multi-energy grid
No full textThe urbanization process is constantly increasing worldwide. Today over 50 % of the population resides in urban areas and this value is expected to grow up to 68 % by 2050. In this scenario, the development of district scale energy grids and management systems has become crucial to optimize energy use and to balance energy flows within the cities, encouraging the use of renewable sources and self-consumption. This study focusses on a district under development in the city of Milan, involving an urban area of about 920 000 m2, which, once completed, will count for about 4 500 apartments, a school and a few other commercial uses. The existing energy systems consist of an electric grid, including a small photovoltaic field, a district heating system and a local district cooling system exploiting groundwater via heat pumps. They serve, at present, seven residential tower buildings (400 apartments). The overarching aim of the research is to evolve the existing grid into a smart energy grid able to guarantee an intelligent management of the district, empowering eventually people to apply for demand-response schemes, electric mobility and other innovative services. In order to perform such an improvement and extension of the exiting grid, it is necessary to evaluate and simulate the profiles and dynamics of the final energy uses for the residential buildings, that will represent the major load on site. Since monitoring data are not yet available for the district, the evaluation of the energy performance of the existing buildings has been developed through dynamic energy simulations via the definition of profile loads of the most frequent apartment typologies, that allow, moreover, to simulate further developments in the districts. Besides, a monitoring plan for the existing systems has been developed and implemented. Monitoring data will be used at first for validating the developed load profiles; then, they will be analysed to develop optimisation algorithms for the management of the upgraded energy grid. In this paper, the case study is presented and the results of the analysis, via energy simulation, on the existing building stock are reported
Scenario attuale e prospettive della climatizzazione a bassa "exergia" verso un mondo radiante
No full textRivista UponorPi
Solar Technologies as a Driver to Limit Energy Poverty in the Rocinha Favela
No full textIn developing countries, the constant conditions of economic and social crises resulted in a continuous expansion of non-regulated solutions to access energy services, especially in low-income settlements of urban areas such as Brazilian favelas, where people rely on illegal connections to the power grid, called gato, to fulfil their energy needs. An appropriate exploitation of renewable energy could reduce these energy thefts, contributing to urban sustainability and creating employment opportunities for locals. This section presents the results of a study developed for a pilot area within the favela of Rocinha, meant to establish ways to limit energy poverty, by spreading access to renewable energy. Both the favela’s energy uses, the potential of local climate and of photovoltaic (PV) panel’s production, have been assessed, leading to the proposal of a solar district based on the use of PV and of battery storage systems. In addition to it, the deployment of an urban management system (UMS), able to manage data coming from different urban facilities, will contribute to outline a new sustainable culture on the use of energy and urban services through the active participation of consumers
Environmental impact assessment of renewable energy communities: the analysis of an Italian neighbourhood
No full textIn recent years, research in renewable energy community (REC) schemes, coupling renewable energy sources and building energy efficiency, is gaining momentum. In this context, Urban Building Energy Modelling tools (UBEMs) have proved to comply with the design requirements of such schemes. However, a clear methodology exploiting UBEMs to support the design of RECs is still missing, especially for assessing the greenhouse gas (GHG) emissions associated with their specific technical configuration. Here, the REC is modelled in “urban modeling interface” (umi), one of the main bottom-up physics-based UBEMs. A building archetype approach is exploited to model the scenarios and assess embodied GHG emissions. The proposed methdology gives the possibility to investigate both the embodied and operational emissions for different REC configuration. A residential neighbourhood in Italy is selected as case study. The results demonstrate the importance of considering building characteristics when analysing emissions reductions in energy-sharing schemes, underlining the necessity of coupling the REC design with energy retrofit interventions
Technical and economic assessment of a battery storage system for a nZEB in the Mediterranean climate
No full textIn recent years, the promotion of nearly-Zero Energy Buildings (nZEB), has become a priority for European member states. In order to get this label, typically, a monthly or yearly energy balance of energy use through the exploitation of renewable energy sources (RES) is required, but not a hourly balance. This approach may determine a low exploitation of the RES on site in the case of solar and wind energy, because they are intermittent by nature. Moreover, energy production and energy use peaks are often in mismatch during the day. Battery energy storage systems (BESS) offer a solution to better integrate RES into buildings as well as into the grid, increasing its reliability and minimizing interactions. The cost of these systems is rapidly decreasing, opening new economic opportunities for investors. However, for many applications they do not yet represent the optimal cost-effective solution due to the lifespan of their short-lived components. The paper investigates the technical and economic feasibility of integrating a BESS into a high-performance residential building in the Mediterranean climate based on the outcomes of an original case study based research. The existing photovoltaic system combined with the BESS may substantially optimize the energy use, maximizing the self-consumption and minimizing grid interactions; nevertheless, the pay-back time may become fully-attractive for the analysed building, only if BESS costs will halve by 2030
From nearly zero energy to carbon‐neutral: Case study of a hospitality building
No full textIn recent years, many cities around the world have pledged to upgrade their building stocks to carbon‐neutral. However, the literature does not yet provide a shared definition of carbon-neutral building (CNB), and the assessment objectives and methodological approaches are vague and fragmented. Starting from the available standards and scientific literature on life cycle assessment (LCA), this paper advances an operational definition for CNB on the basis of an explicit calculation approach. It then applies the definition to an urban case study, comparing it against a state-of‐the‐art nearly Zero Energy Building (nZEB) scenario, with the intent of highlighting the major practical limitations connected to the application of a methodologically sound carbon neutrality cal-culation. The case study shows that carbon neutral objectives can hardly be achieved by single urban buildings because of the lack of spaces that can provide onsite carbon offsetting actions. Carbon neutrality may be better approached at the city, regional, or national scales, where overarching policies may be defined
A simulation-based assessment of technologies to reduce heat emissions from buildings
No full textHeat emissions from buildings are part of anthropogenic heat leading to urban overheating. This paper aims to assess how technologies (i.e., energy conservation measures - ECMs), used to decrease energy use, may also reduce heat emissions from buildings. This study employs the physics-based engine EnergyPlus to simulate the main components of heat emissions from buildings to ambient air: envelope, zone, and systems. Hourly simulations are run for IECC single- and multi-family reference models with three representative climates: Miami, Baltimore, and Chicago. The results show that the performance of ECMs varies among weather, seasons, and residential typologies. Particularly, some ECMs (i.e., cool coatings, heat pumps, additional insulation, energy-awareness occupants) show a strong decrease in heat emissions, yet they are not always correlated with proportional decreases in energy use. When all ECMs are combined, the reductions are larger on heat emissions (89%) than on site energy (65%) from the base cases. During summer in Miami, the combination of ECMs shows a decrease in heat emissions from the building surface component of 80% during daytime, 92% for the HVAC component and a counterbalanced increase in the zone component of 88%, bringing to a daily decrease in total heat emissions. The main contributions of this study are quantifying how typical ECMs influence residential building heat emissions using EnergyPlus simulations and informing urban planners and stakeholders on prioritizing measures for mitigating urban overheating problems
Effects of COVID-19 confinement on the simulation of energy needs and uses of residential buildings in Milan
No full textThis paper examines the impact of COVID-19 confinement on the simulation of energy needs and uses of residential buildings in Milan. Data-driven schedules for electricity use before and during lockdown, derived from smart metering data, are applied to an urban building energy model to analyze their effects on energy needs for heating and cooling and the energy use for lighting and for other services. Electricity uses, heating and cooling needs, and total primary energy (TOE) are compared for pre-COVID and during-COVID cases. Electricity increases by 8%, while heating decreases by 10%, and cooling increases by 26%. The 5% decrease in TOE is mainly due to the decrease in heating. The study uses heat maps to display the coefficient of variation of root mean square error (CVRMSE) at different temporal and spatial aggregations, indicating significant differences between pre- and during-COVID cases. The CVRMSE for electricity consumption is highest at the hourly level for single buildings, reaching a maximum of 44, and decreases at higher levels of aggregation. The CVRMSE for TOE is highest at the hourly level for single buildings, reaching a maximum of 230. A scenario is created by combining during-COVID and pre-COVID schedules for a hybrid work model, called post-COVID. The post-COVID scenario results indicate a significant impact of remote work on energy consumption patterns
Assessing energy performance of smart cities
No full textThe massive urbanization process registered since 1950s and projected to continue for the coming decades is posing a crucial issue for the management of existing cities and the planning of future ones. Smart cities are often envisioned as ideal urban environments where the different dimensions of a city, such as economy, education, energy, environment, finance, etc., are managed in an effective and proactive way. Nevertheless, in order to reach this remarkable and challenging objective, analysis tools are required to create scenarios that are able to inform policy makersâ decisions. Focusing on energy, this paper proposes an analysis method, based on exergy, to support smart city planning. It may help the decision makers to assess the energy-smartness of different scenarios, and to address urban energy policies. Possibilities and limitations of the analysis method are discussed via the application to the cities of London, Milan, and Lisbon that committed to become smart cities. Practical application: The paper summarizes a study on the possibilities and limitations of adopting an assessment technique, based on exergy, in order to evaluate the energy-smartness of policies in existing and future smart cities. As highlighted in the paper, buildingâs energy uses have a huge share of many citiesâ energy breakdown. Thus, professionals in the building industry will be interested in the paper not only because it refers to smart cities, but because the built environment plays a pivotal role in them. Professionals may also refer to this study to perform a similar analysis in other urban environments to support decision makers
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