The construction industry is one of the most environmentally detrimental industries in the world, impacting directly the use of raw materials, their determination of use involving the whole lifecycle, as well as all their surrounding environment. However, within the building sector, the transition from a linear to a circular economy is still at an early stage. Business models need to be reconsidered to include new and improved methods and innovative services that could lead to a net reduction in the use of resources and minimizing the waste disposed on landfills. In this context, an important role in buildings’ circularity is “deconstruction”, which is understood as a well-considered selective dismantlement of building components, in prevision of a future reuse, repurposing, or recycling. It represents a sustainable alternative to common demolition, which tends to be an arbitrary and destructive process, and although faster and cheaper, it typically creates a substantial amount of waste. The purpose of this article is to analyze the deconstruction potential of buildings and the strategies to apply in order to keep the impacts on the urban environment low. The article aims to facilitate the implementation of circular economy strategies for buildings by proposing common principles for deconstruction as a sustainable alternative to demolition and defining the key points to be applied during the design and planning process regardless of the type of construction system or material used.

With the third revision of the Energy Performance of Buildings Directive (EPBD) issued in July 2018, the assessment of buildings now has to include a Smart Readiness Indicator (SRI) to consider the fact that buildings must play an active role within the context of an intelligent energy system. In order to support the development of the SRI, this article describes a methodology for a simplified quantitative assessment of the load shifting potential of buildings. The aim of the methodology is to provide a numerical, model-based approach, which allows buildings to be categorized based on their energy storage capacity, load shifting potential and their subsequent interaction with the grid. A key aspect is the applicability within the Energy Performance Certificate (EPC) in order to provide an easy to use calculation, which is applied in addition to the already established energy efficiency, building services and renewable energy assessments. The developed methodology is being applied to theoretical use cases to validate the approach. The results show that a simplified model can provide an adequate framework for a quantitative assessment for the Smart Readiness Indicator.

Urban strategies and the way cities are planned have changed throughout history, adapting to the needs of the inhabitants, infrastructure requirements, and advances in technology. Uses and customs of people and cities are changing and can evolve much faster than in the past, with the result that urban planning is often too slow to adequately meet the current needs of society. In this context, the development of pop-up environments for temporary developments could be a solution to meet the needs of flexibility, adaptation, and resilience of a city. This allows the urban planner to consider systems from a short-term perspective, fulfilling current needs without compromising the development of potentially different activities in the future. The purpose of this research work is to outline the general requirements of pop-up environments in urban developments that allow for adequate integration into urban planning strategies. Based on an extensive evaluation of the existing literature and a series of case studies, the paper analyzes the key elements that define the framework conditions of urban planning strategies for temporary developments that generate a positive impact on the overall urban system.

The waste heat generated from the use of air conditioning systems in cities significantly contributes to the urban heat island effect (UHI) during the summer months. Thus, one of the key measures to mitigate this effect is to limit the use of active cooling systems. In the city of Vienna, air conditioning units are common in nonresidential buildings, but have so far been much less installed in residential buildings. This is mainly due to the fact that the Viennese summertime climate is still considered to be relatively comfortable and planning guidelines related to energy efficiency are already strict, resulting in high-quality buildings in regard to thermal performance. However, during the last decade, an increase in summertime temperatures and so called “tropical nights” has been recorded in Vienna and subsequently the postconstruction installation of air conditioning systems in residential buildings has significantly increased. In a study undertaken for the City of Vienna, a series of passive design measures have been simulated with current and future climate scenarios in order to determine the most effective combination of architecturally driven actions to avoid the use of air conditioning systems in residential buildings whilst maintaining comfortable indoor temperatures.

In Nigeria, there is an estimated deficit of 17 million housing units. Power supply is insufficient, and the electricity supply for about 60 million Nigerians relies on private generators, causing noise, pollution, and high expenditures for mainly imported fuel. Altogether, current challenges clearly demonstrate the need for effective energy efficiency policies targeting also the building sector. The Nigerian Energy Support Program began in 2013, among others, with the objective being to support the Nigerian Government in developing the Nigerian Building Energy Efficiency Code. This paper presents two preparatory activities carried out in order to come up with suggestions for a legal framework well suited for the situation on the ground: the Case Study Building Analysis carried out in collaboration with a Nigerian developer and the Nigerian Building Energy Efficiency Guideline, elaborated together with stakeholders. The results of preparatory activities pointed out that the code must put emphasis on climate adaptive design and must define requirements and procedures in a clear and simple way to allow for effective enforcement. Only then can energy-efficient mass housing be feasible in Nigeria. The paper concludes with a description of the Nigerian Building Energy Efficiency Code (BEEC), officially approved and launched by the Federal Minister of Power, Works and Housing on 29 August 2017.

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In urban areas, summer temperatures are continuously increasing, and cities are aiming at implementing measures to mitigate the urban heat island (UHI) effect. Reducing sealed surfaces and adding plants have been shown to be beneficial for urban microclimates. Green roofs are thus a viable alternative to standard roofs made out of materials that completely seal the top layer. However, roofs are, at the same time, also ideal for the integration of photovoltaics (PVs), as they are mostly unshaded. With both applications competing for the same surface area, solutions must be found that symbiotically combine the benefits of vegetation and renewable energy. Using an interdisciplinary study, various designs were developed for prototypical applications to integrate PV systems into rooftop gardens, with a specific focus on retrofitting flat roofs. The prototypes were analyzed and tested based on structural design aspects, suitable plant choices, and energy output. The results showed that the concurrent integration of PVs and green roofs into the same surface area can be achieved with lightweight construction, which is particularly suitable for existing buildings. The system can contribute to much-needed urban renewable energy generation, the mitigation of the UHI effect, and the provision of recreational spaces.

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