• Energy Research

Recent efforts to reduce energy consumption and greenhouse gas emissions have resulted in the development of sustainable, smart districts with highly energy efficient buildings, renewable distributed energy resources (DERs), and support for alternative modes of transportation. However, there is typically little if any coordination between the district developers and the local utility. Most attention is paid to the district's annual net load and generation without considering their instantaneous imbalance or the connecting network's state. This presents an opportunity to learn lessons from the design of distribution feeders for districts characterized by low loads and high penetrations of DERs that can be applied to the distribution grid at large. The aim of this overview is to summarize current practices in sustainable district planning as well as advances in modeling and design tools for incorporating the power distribution system into the district planning process. Recent developments in the modeling and optimization of district power systems, including their coordination with multi‐energy systems and the impact of high penetration levels of renewable energy, are introduced. Sustainable districts in England and Japan are reviewed as case studies to illustrate the extent to which distribution system planning has been considered in practice. Finally, newly developed building‐to‐grid modeling tools that can facilitate coordinated district and power system design with utility involvement are introduced, along with suggestions for future research directions.This article is categorized under: Wind Power > Systems and Infrastructure Energy Policy and Planning > Systems and Infrastructure Energy Efficiency > Systems and Infrastructure

Urban Built Environments (UBE) are increasingly prone to SLow-Onset Disasters (SLODs) such as air pollution and heatwaves. The effectiveness of sustainable risk-mitigation solutions for the exposed individuals’ health should be defined by considering the effective scenarios in which emergency conditions can appear. Combining environmental (including climatic) conditions and exposed users’ presence and behaviors is a paramount task to support decision-makers in risk assessment. A clear definition of input scenarios and related critical conditions to be analyzed is needed, especially while applying simulation-based approaches. This work provides a methodology to fill this gap, based on hazard and exposure peaks identification. Quick and remote data-collection is adopted to speed up the process and promote the method application by low-trained specialists. Results firstly trace critical conditions by overlapping air pollution and heatwaves occurrence in the UBE. Exposure peaks (identified by remote analyses on the intended use of UBEs) are then merged to retrieve critical conditions due to the presence of the individuals over time and UBE spaces. The application to a significant case study (UBE in Milan, Italy) demonstrates the approach capabilities to identify key input scenarios for future human behavior simulation activities from a user-centered approach.

Abstract Greenhouse gas emissions have been recognized as one of the major cause of the global warming phenomena. The built environment accounts for more than 40% of the overall energy consumption and 36% of the overall CO2 emissions in Europe. Recent studies show that housing is one of the most responsible sector for world ecological impacts. The European Parliament developed the concept of Nearly Zero Energy Buildings (NZEB), characterized by a very low energy demand and a high renewable energy on-site production. In fact, energy efficiency is the first step towards the ambitious aim to reduce of 80% by 2050 the EU carbon emissions. The zero-energy building target is an achievable goal, which relies on a careful design that encompasses a synergy between passive and low-energy strategies. However, considering the whole life cycle of buildings, NZEBs reduce the operational energy close to zero, increasing the relevancy of the embodied energy, which occurs during the construction phase. Balancing the values of the operational and embodied energy is necessary to minimize buildings footprint on the environment. In this paper the renovation and re-use of the Atika building, a demonstrative energy-efficient building, is presented as case study of an environmental efficient methodology for energy retrofitting. The case relies on the methodology developed by Active House, a holistic vision for sustainable buildings labeling.

AbstractA critical gap between the occupant behaviour research field and the building engineering practice limits the integration of occupant-centric strategies into simulation-aided building design and operation. Closing this gap would contribute to the implementation of strategies that improve the occupants’ well-being while reducing the buildings’ environmental footprint. In this view, it is urgent to develop guidelines, standardised methods, and supporting tools that facilitate the integration of advanced occupant behaviour models into the simulation studies. One important step that needs to be fully integrated into the simulation workflow is the identification of influential and non-influential occupant behaviour aspects for a given simulation problem. Accordingly, this article advances and demonstrates the application of the Impact Indices method, a fast and efficient method for screening the potential impact of occupant behaviour on the heating and cooling demand. Specifically, the method now allows the calculation of Impact Indices quantifying the sensitivity of building energy use to occupancy, lighting use, plug-load appliances use, and blind operation at any spatial and temporal resolution. Hence, users can apply it in more detailed heating and cooling scenarios without losing information. Furthermore, they can identify which components in building design and operation require more sophisticated occupant behaviour models. An office building is used as a real case study to illustrate the application of the method and asses its performance against a one-factor-at-a-time sensitivity analysis. The Impact Indices method indicates that occupancy, lighting use and plug-load appliances have the greatest impact on the annual cooling demand of the studied office building; blind operation is influential only in the west and south façades of the building. Finally, potential applications of the method in building design and operation practice are discussed.

Energy efficiency in the building sector plays a key role in supporting European and global commitments against the current climate crisis. A massive adoption of deep renovation measures would allow a global reduction of energy need up to 36%, based on estimations. However, the market for building renovation is still limited, due to uncertainties associated with risk evaluation. This paper aims to suggest a method to evaluate the financial impacts of technical risks related to energy efficiency investments. Key performance indicators (KPIs) necessary to evaluate the investment risk associated with energy renovation have been defined based on an analysis of the correlation between technical and financial risks, and their originating factors or root causes. The evaluation has been carried out thanks to the EEnvest tool: a web-based search and match platform, developed within the EEnvest collaborative research project funded by the European Commission (EC). This evaluation methodology has then been applied to a case study, an office building located in Rome, for whom an energy efficient renovation project was already in place to reduce energy needs. The investment risk of the renovation project is calculated for two different scenarios: with and without risk mitigation measures being applied during the design, installation and operation phases. The results show the different technical and financial risk trends of these two scenarios, highlighting the benefits obtained by the implementation of mitigation measures.

Starting from an experimental activity, the paper describes research analysis that has been conducted on a real case construction with the aim to design its adaptation as a nearly zero energy building in three possible alternative scenarios: (i) a lab for students’ activities in the Lecco University Campus of Politecnico di Milano; (ii) an Alpine shelter for the implementation of a sustainable mountain tourism in Zermatt; (iii) an emergency shelter for poor communities in Burkina Faso. The use of an easily disassembled and lightweight steel structure coupled with dry-layered technologies allows a tailor-made envelope design, ensuring high thermal comfort, very low energy use, and limited construction times. The three case studies have been designed starting from the same architectural/structural concept. A detailed analysis, by means of finite element method and dynamic building thermal simulations, has been performed to predict the overall performances of each case study. The results show: (i) high replicability of the concept; (ii) high customization of the envelope technologies; (iii) high energy efficiency; and (iv) high thermal comfort of the architecture. The useful energy requirement in all the three analyzed scenarios is minimized and equal to 14.13, 23.88, and 41.83 kWh/m2 year, respectively, for the students’ lab, the Alpine shelter and the emergency shelter. According to this study the energy needs can be covered by renewable energy produced on site, making the architectural concept an interesting modular lightweight solution for a nearly zero energy building with high potential for replicability.

Abstract The revised Energy Performance of Buildings Directive (EU) 2018/844 has huge potential for efficiency gains in the EU building sector, including measures that should accelerate the rate of building renovation towards more energy efficient systems. Under the 2010 EPBD, all EU countries have established independent energy performance certification systems supported by independent mechanisms of control and verification. However, current practices and tools of energy performance assessment and certification applied across Europe face several challenges. The paper presents an overview on researches and tools for the European building stock renovation process with the goal to highlight barriers, limits and benefits to increase the energy renovation rate. The main focus is to clarify the energy performance assessment and process for the certification and the introduction of the Building Renovation Passport, considering the novelty introduced by latest regulations and standards.