The paper describes the progress of the four-year European project Pro-GET-onE currently under implementation. This research and innovation project is based on the assumption that greater efficiency, attractiveness, and marketable renovation can only be achieved through an integrated set of technologies where all the different requirements (energy, structural, functional) are optimally managed. Thus, the project focuses on the unprecedented integration of different technologies to achieve a multi-benefit approach that is provided by a closer integration between energy and non-energy related benefits. The project aims to combine different pre-fabricated elements in a unified and integrated system resulting in a higher performance in terms of energy requirements, structural safety, and social sustainability. The project attempts to achieve this goal through the introduction of innovative solutions for building envelopes to optimally combine the climatic, structural, and functional aspects through a significant architectural transformation and a substantial increase of the real estate value of the buildings. This augmented value obtained through the application of the inteGrated Efficient Technologies (GETs) is extremely important when considering the necessity of creating an innovative and attractive market in the energy renovation of existing buildings towards the target of nearly zero energy buildings (nZEBs).

This paper focuses on the definition of a method supported by digital processes for a sustainable and user-orientated re-design of the existing building stock. Based on the analysis of the methodological and procedural aspects of the computational approach to architectural design in relation to different performance conditions, the research addresses the adoption of Building Information Modeling (BIM), intended as a powerful method for coordinating the complexity of the multiple, interdisciplinary and conflicting aspects involved in the rehabilitation of buildings. In addition to the advantages in terms of control and management, the BIM process has proven its effectiveness in tackling the issue of sustainability, allowing all actors involved in the research to share information and pro-actively control various outcomes of a building’s performance, such as energy and environmental quality. To show the opportunities and limitations of the digital management in information-based processes, the activities carried out in the framework of the European Horizon 2020 project “Pro-GET-onE—Proactive synergy of inteGrated Efficient Technologies on buildings’ Envelopes” are reported. The research, based on a case study method, which is applied to a student residence in Athens, demonstrates that BIM possesses great potentialities for developing effective and efficient construction and renovation processes toward buildings with high quality standards.

The achievement of sustainable cities and communities is closely linked to an accurate design of the buildings. In this context, the transparent elements of the building envelope have a crucial role since, on one hand, they are a bottleneck in regards to heat and mass transfers and sound propagation, while, on the other hand, they must allow daylight penetration. Thus, they are responsible for occupants’ thermal and visual comfort and their health. Considering passive solutions for windows, the light shelves can improve natural light penetration, reducing the lights’ electricity demand and controlling windows’ related thermal aspects. The scientific literature is characterized by several studies that analyze this topic, which, however, focus only on the daylight field and sometimes the energy saving for lights. Moreover, they often refer to fixed sky type for the simulations. The aim of the present study is to analyze the application of the light shelves with a multi-disciplinary approach, by means of dynamic simulations, in the EnergyPlus engine, for a whole year. A new methodological approach is presented in order to investigate the technology under different fields of interest: daylight, lighting energy, cooling and heating needs, and thermo-hygrometric comfort. The case study chosen is an existing building, a student dormitory belonging to the University of Athens. It is subject to a deep energy renovation to conform to the “nearly Zero Energy Building” target, in the frame of a European research project called Pro-GET-onE (G.A No. 723747). By means of the calibrated numerical model of this HVAC–building system, ten different configurations of light shelves have been investigated. The best solution is given by the application of an internal horizontal light shelf placed at 50 cm from the top of the window with a depth of 90 or 60 cm. It has been found that despite the reduction in electricity demand for lighting, the variation in heating and cooling needs does not always lead to a benefit.

On a European scale, the existing building stock has poor energy performance and particularly vulnerable structures. Indeed, most of the existing buildings were built before the introduction of energy standards and under structural safety criteria different from those currently required. It is therefore necessary the intervention in existing buildings according to an integrated approach that contemplates both the structural safety and the energy efficiency of buildings. This study, consistently with the objectives of the European research project “Proactive synergy of integrated Efficient Technologies on buildings’ Envelopes (Pro-GET-OnE)”, proposes a retrofit intervention for a student dormitory of the National and Kapodistrian University of Athens. The scope of the evaluation is to understand how an integrated intervention, that implies a structural and energy retrofit, as well as a spatial redistribution, leads to an improvement of the Indoor Environmental Quality (IEQ). In detail, the structural retrofit was performed through exoskeleton that leads to the addition of new living spaces and to a remodeling of the building facades. The energy retrofit regarded all three levers of energy efficiency, and thus the building envelope, the microclimatic control systems, and the systems from renewable sources. The integrated intervention, in addition to a reduction of energy demand, has led to advantages in terms of IEQ. Thermal comfort, both during summer and winter, is improved and the hours of suitable CO₂ concentration pass from 34% in the pre-retrofit stage up to 100% in the post retrofit stage.

The current main issue in the construction sector in Europe concerns the energy refurbishment and the reactivation of investments in existing buildings. Guidance for enhancing energy efficiency and encouraging member states to create a market for deep renovation is provided by a number of European policies. Innovative methods and strategies are required to attract and involve citizens and main stakeholders to undertake buildings’ renovation processes, which actually account for just 1% of the total building stock. This contribution proposes technical and financial solutions for the promotion of energy efficient, safe, and attractive retrofit interventions based on the creation of volumetric additions combined with renewable energy sources. This paper focuses on the urban reality of Athens as being an important example of a degraded urban center with a heavy heat island, a quite important heating demand, and a strong seismic vulnerability. The design solutions presented here demonstrate that the strategy of additions, because of the consequent increased value of the buildings, could represent an effective densification policy for the renovation of existing urban settings. Hence, the aim is to trigger regulatory and market reforms with the aim to boost the revolution towards nearly zero energy buildings for the existing building stocks.