Sustainable urban regeneration through densification strategies: the Kallithea district in Athens as a pilot case study

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 degraded urban center with a heavy heat island, a quite important heating demand, and a strong seismic vulnerability. The design solutions here presented 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

Energy and Architectural Retrofitting in the Urban Context of Athens

Cities are the main receptors of energy demand pressures and climate change. Energy consumptions of existing buildings in urban areas on the one side, and the combination of heat island phenomena, fuel poverty and global overheating on the other side, are threatening both built environment and inhabitants. The volumetric configuration of the urban textures and the materials that constitute the external surfaces, are the main factors that influence the microclimate of a city. Comprehend and being able to transform in an adequate way the urban settings could contribute to the improvement of the thermal comfort in outdoor and indoor built environments. By using as a principal comfort indicator the variation of the external temperatures in an unprecedented collaboration between different scales and different environmental simulation systems, this research work analyzes the energy saving potential given by the use of green and passive techniques and shows the synergies that may arise between outdoor and indoor spaces. The research work has tested the effects on the urban microclimate of the transformations induced in the outer urban spaces and, in parallel, how these modifications effect the reduction of temperature in the confined indoor spaces of the built environments. Open spaces and the surface of urban volumes are considered, measured and evaluated as a unique interacting environment

PROGETTAZIONE PARAMETRICA PER LA VALUTAZIONE DELLE ADDIZIONI DI FACCIATA NEGLI EDIFICI ESISTENTI (Parametric design evaluation of user orientated pre-fab modules for the fa\ue7ade addition in existing buildings)

Questo contributo descrive alcune potenzialit\ue0 delle modellazioni parametriche applicate alla trasformazione degli involucri edilizi; in particolare, tale trasformazione si riferisce alle addizioni volumetriche ottenute attraverso l\u2019impiego di nuove strutture poste sulle facciate degli edifici costruiti in struttura intelaiata in conglomerato cementizio armato. La modifica di tali fabbricati attraverso strutture esterne consente un incremento degli spazi abitativi secondo soluzioni modulari selezionabili in base alle diverse esigenze. Per aumentare l\u2019impatto e la scala della strategia promossa dal progetto, le diverse configurazioni geometriche e spaziali sono state studiate e modellate parametricamente in modo da verificarne la possibile reiterazione in diversi casi. Le soluzioni modulari (denominate GET) sono configurabili come una stanza in pi\uf9, un balcone o una serra e le diverse opzioni variano al variare delle possibili risultanze in termini di capacit\ue0 strutturale, adattabilit\ue0 rispetto alle condizioni geometriche dell\u2019esistente, comportamento energetico, risultato formale. Tale sistema \ue8 oggetto di studio all\u2019interno del progetto di ricerca ProGET-onE, finanziato nell\u2019ambito delle \u201cInnovation Action\u201d del programma Europeo H2020This paper describes some potentialities of the parametric modeling applied to the transformation of building envelopes; in particular, this transformation refers to the volumetric additions brought about by new structures placed on the facades of the existing buildings framed in reinforced concrete structure. These facade additions are meant to improve the energy, structural and functional performance renovation strategy based. The research is included in the EU H2020 project Pro-GET-onE, which proposes the transformation of the building envelope with external structures to increase the living space and the attractiveness of the building with modular fa\ue7ade solutions that can be selected according to the needs and expectations of users. These modules can in fact be configurable as an extra room, a balcony and a solar greenhouse. To increase the possible reiteration of the strategy, the research has implemented hypotheses of possible geometric and spatial configuration through a parametric approach to evaluate their applicability to structures with different structural, geometric and architectural characteristics; the same verification tool is also used to extend the range of more convincing and attractive figurative solution

Building Information Modeling as an Effective Process for the Sustainable Re-Shaping of the Built Environment

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

A European Project for Safer and Energy Efficient Buildings: Pro-GET-onE (Proactive Synergy of inteGrated Efficient Technologies on Buildings\u2019 Envelopes)

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)

Energy, Environmental Impact and Indoor Environmental Quality of Add-Ons in Buildings

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

An Integrated System for Fa\ue7ade Additions Combining Safe, Energy Efficient and User-Orientated Solutions

This research work, as part of the Horizon H2020 project, Pro-GET-onE (Horizon 2020 GA No. 723747), aims to demonstrate the attractiveness of a renovation strategy based on new fa\ue7ade additions that combine integrated technologies (GET) to achieve high standards in terms of socio-economic, energy and seismic performance. This document investigates, in particular, the possible transformation of the existing building envelope with external reinforcement structures, which generate energy-efficient buffer zones and at the same time increase the volume of the building

IEQ and energy improvement of existing buildings by prefabricated facade additions: the case of a student house in Athens

The aim of this paper is to evaluate and illustrate the energy saving potential and Indoor Environmental Quality (IEQ) performances of a fa\ue7ade addition on existing and low energy performing buildings. Different technical solutions are proposed and all IEQ indicators\u2019 simulation results are presented for the case of a students\u2019 building block of the 80\u2019s located in Athens. The building is the demonstrator of the \u201cPro-GET-onE\u201d Horizon 2020 project, that aims to demonstrate the attractiveness and the energy efficiency of a renovation strategy based on new fa\ue7ade additions combining inteGrated Efficient Technologies (GETs). The research project proposes the highest transformation of the existing building\u2019s shell with external added volumes, which generate energy efficient buffer zones and at the same time increase the building\u2019s volume (with balconies, sunspaces and extra rooms). This strategy gives also the possibility to increase IEQ performance, in different ways depending on the architectural solutions, the selected materials and the adopted technological solutions. As a general statement, the facade addition solution leads to an increase of the thermo-hygrometric conditions (both for the cold winter season and the summer period), of the facade sound insulation and consequently the acoustic comfort, and of the indoor air quality. The lighting and the visual comfort are a critical point due to the enlargement of the existing surface of the rooms: specific light enhancement techniques have been studied to optimize indoor light, therefore minimizing the drawbacks of fa\ue7ade expansions, and will be suggested for the final design of the case study. The detailed analysis of individual units (additions) led to the formulation of hypotheses for targeted energy retrofitting interventions in different options; with different scenarios of integrated RES technologies, these options have been analysed both separately and in combination, to assess the technical, the energy feasibility and the IEQ performance in each scenario

Multi-Objective Optimization for Cooling and Interior Natural Lighting in Buildings for Sustainable Renovation

In order to achieve the ‘nearly zero-energy’ target and a comfortable indoor environment, an important aspect is related to the correct design of the transparent elements of the building envelope. For improving indoor daylight penetration, architectural solutions such as light shelves are nowadays commercially available. These are defined as horizontal or inclined surfaces, fixed or mobile, placed on the inner and/or the outer side of windows, with surface features such to reflect the sunlight to the interior. Given the fact that these elements can influence different domains (i.e., energy need, daylighting, thermal comfort, etc.), the aim of this paper is to apply a multi-objective optimization method within the design of this kind of technology. The case study is a student house in the University of Athens Campus, subject to a deep energy renovation towards nZEB, under the frame of H2020 European project Pro-GET-onE (G.A No 723747). Starting from the numerical model of the building, developed in EnergyPlus, the multi-objective optimization based on a genetic algorithm is implemented. The variables used are various light shelves configurations by differing materials and geometry, as well as different window types and interior context scenarios. Finally, illuminance studies of the pre- and post-retrofit building are also provided through Revit illuminance rendering