Building energy-consumption status worldwide and the state-of-the-art technologies for zero-energy buildings during the past decade

In recent years, energy efficiency and thermal comfort in historic buildings have become high-interest topics among scholars. Research has demonstrated that retrofitting buildings to current energy efficiency and thermal comfort standards is essential for improving sustainability and energy performance and for maintaining built heritage of historic structures. This study is an extensive overview of the literature surrounding this topic. This paper summarizes the different methods and techniques that have been used around the world to achieve performance refurbishments. Articles are organized based on the different building types used as case studies (residential, religious, academic and palace, museums, libraries and theaters, urban areas, and others). The results reveal that residential, religious and museum building types, especially from the last two centuries, have been most often used as case studies. Moreover, Europe, particularly Italy, is leading the research. The aim of this note is to demonstrate the feasibility of maintaining built heritage values of historic buildings while achieving significant improvements in their energy efficiency and thermal comfort.

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Energy efficiency and thermal comfort in historic buildings: A review

The global response to warming of 1.5oC comprises transitions in land and ecosystem, energy, urban and infrastructure, and industrial systems. The feasibility of mitigation and adaptation options, and the enabling conditions for strengthening and implementing the systemic changes, are assessed in this chapter.

Strengthening and Implementing the Global Response

Embodied energy in residential buildings-towards the nearly zero energy building: A literature review

The enhancement of energy performance of buildings has become a pillar of energy policies. The main target is the cut of energy consumption to reduce buildings footprint. This aim is pursued by introducing constrains on building requirements in terms of properties of basic materials and components and exploitation of renewable energy sources . That results in the definition of the zero-energy building (ZEB) concept. The new paradigm introduced new challenges and, at the same time, involved all the different stakeholders in facing the barriers to the diffusion of the novel solutions proposed by the research development. This paper summarizes the actual state-of-art of whole performance of ZEBs and the related technical solutions, analysing their increasing potential in energy consumption. A collection of the different case studies reported in literature involving ZEBs is presented, compiling an analysis of the performance of the common solutions actually applied. The technologies involved are described discussing their impact in meeting the ZEB requirements. A debate is proposed, pointing out the main aspects deserving further investigations and outlining the critical elements in making the zero-energy target the new standard for the buildings.

A review of performance of zero energy buildings and energy efficiency solutions

The reduction of energy consumption in buildings is an important pillar of the European strategy to ensure that future climate and energy targets are reached. This paper focuses on the definition of Nearly zero energy buildings (NZEBs) that represent one of the greatest opportunities to increase energy savings in Europe. As this term appears to be subject to different interpretations, the paper explores the NZEB literature to provide an overview of definitions. The analysis underlines inconsistencies and critical issues among them. The paper also assesses the progress of the NZEB implementation in Europe, and compares the EU-NZEBs and the US-NZEBs definitions. The main debates arisen around NZEBs are evaluated. Among these topics, there are: the distinction between energy and primary energy, and between energy sources and energy carriers. A focus is also due to metrics and primary energy conversion factors. Special attention is provided in defining primary energy factors for energy carriers produced from renewable energy sources on site, nearby or far. After specifying the role of “plus” buildings, a complementary energy index, useful for defining incentives for buildings is formulated to overcome the questioning on the “negative” primary energy index that can be achieved using some of current net ZEB definitions. A proposal for clarifying the meaning of near zero, zero and plus energy buildings is also given. The analysis highlights that, although the attention given to NZEBs increased over the last years, the NZEB topic is still under discussion and not uniformly implemented.

https://re.public.polimi.it/bitstream/11311/1157272/1/What%20is%20a%20Nearly%20zero%20energy%20building%20...pdf

What is a Nearly zero energy building? Overview, implementation and comparison of definitions

Review of 50 years of EU energy efficiency policies for buildings

A framework for the cost-optimal design of nearly zero energy buildings (NZEBs) in representative climates across Europe

Buildings are the focus of European (EU) policies aimed at a sustainable and competitive low-carbon economy by 2020. Reducing energy consumption of existing buildings and achieving nearly zero energy buildings (NZEBs) are the core of the Energy Efficiency Directive (EED) and the recast of the Energy Performance of Building Directive (EPBD). To comply with these requirements, Member States have to adopt actions to exploit energy savings from the building sector. This paper describes the differences between deep, major and NZEB renovation and then it provides an overview of best practice policies and measures to target retrofit and investment related to non-residential buildings. Energy requirements defined by Member States for NZEB levels are reported comparing both new and existing residential and non-residential buildings. The paper shows how the attention given to refurbishment of NZEBs increased over the last decade, but the achievement of a comprehensive implementation of retrofit remains one of main challenges that Europe is facing.

Delia D'Agostino

Papers

What is a Nearly zero energy building? Overview, implementation and comparison of definitions

Review of 50 years of EU energy efficiency policies for buildings

A framework for the cost-optimal design of nearly zero energy buildings (NZEBs) in representative climates across Europe

Towards Nearly Zero Energy Buildings in Europe: A Focus on Retrofit in Non-Residential Buildings

Energy consumption and efficiency technology measures in European non-residential buildings