• Energy Research

Ventilated Façades integrating photovoltaic panels are a promising way to improve efficiency and the thermal-physical performances of buildings. Due the inherent intermittence of the non-programmable renewable energy sources, their increasing usage implies the use of energy storage systems to mitigate the mismatch between power generation and the buildings' load demand. The main purpose of this paper is to investigate the thermo-fluid dynamic performances of a prototype integrating a photovoltaic cell and a battery as a module of an active ventilated façade. Based on an experimental setup, a numerical study in steady state conditions of flow through the air cavity of the module has been carried out and implemented in a fluid-dynamics Finite Volume code. In order to assess the viability of the prototype, the calibrated model was lastly used to predict thermal performance of the prototype on different climate conditions supporting its further improvement.

Climate Change represents a priority, due to the large variety of implications and importance that it has reached throughout the last decades. In an effort to address this global and local challenge and in order to restrict temperature rise to 2 °C over the next century, it will need to address this topic from several angles, as confirmed by the last COP meetings in Paris and in Marrakech. In this context, the paper presents the modelling and assessment of ventilative cooling applicability in the future of the Mediteranean area under the effects of climate change. Results show that natural ventilation will continue to be of paramount importance in the Mediterranean climate but its highest effectiveness will be displaced from summer to spring and autumn.

Climate change and its effects are becoming clear on a global scale either from the perspective of global warming and the increase in the rate of occurrence of weather events of extreme magnitude. This has impacts also for sure on the standard building performance analysis approach, since the buildings designed today are supposed to withstand for the following decades climate impacts that may be different than those they were designed for. The paper proposes a simple, easy to use and freely available building simulation utility which performs morphing of existing weather data files and, by connecting to the Energy Plus simulation routine, allows to perform future climate building simulation analyses. Users are required to select one of the ASHRAE buildings models or provide one of their own choosing and to input the original weather data file. The tool will generate a future weather data file with the preferred assumptions (e.g. RCP scenarios, time frame) and elaborate results in terms of heating and cooling required for air conditioning. The paper proposes also an implementation of the tool to a case study aimed at showing the potential of the application proposed. A typical office building model from the ASHRAE library was simulated in two different locations under different climate change assumptions up to the year 2090. The analysis of the results in the two locations of Palermo (Italy) and Copenhagen (Denmark) highlight relevant increases in the current century of up to +20% of cooling requirements and similar reductions for heating in both case studies, if compared to current levels. The research targets a specific limit in the investigation of climate resilience of buildings and follows the principles described by SDSN in the definition of SDGs and the interest at the EU level towards climate neutral and innovative cities. In this context, the paper may contribute to the limited availability of easy to use and free tools available for practitioners to investigate the design of climate resilience buildings.

The concept of Positive Energy District is one of the main areas of research and extensive applications of the principles of the clean energy transition within the building sector. In the past years, the most widely accepted definitions have focused specifically on carbon neutrality, while several other aspects regarding all sustainability approaches (including environmental, social and economic perspective) were included qualitatively or to a lesser degree. This paper proposes a discussion on the state of the art of the sustainability assessment of Positive Energy Districts, by investigating environmental, social and economic sustainability applications. The three sustainability dimensions are investigated individually first, while discussing methodological insights, key performance indicators used and quantitative results, as well as in an integrated perspective. Finally, the paper describes research gaps and areas for further development on the topic.

The paper explores the energy performances and environmental impacts of a prefabricated building module located in Messina (Sicily, Italy) through an approach that combines both the non-steady state building simulation and the Life Cycle Assessment methodology. The building uses renewable energy technologies and is usable in emergency situations or as simply temporary housing. Results show that the building module causes the emission of 1.5 t of CO/m and consumes 29.2 GJ/m of primary energy during its life cycle. The building achieves the Net Zero Energy Building target even if it has relevant environmental impacts in the materials production stage (72% on average of the total impacts while the use stage reaches the 23% on average). The construction and the end-of-life stages give a marginal contribution to the total impacts, since they account for the 1% and the 3%, respectively.

The concept of load matching refers to the degree of agreement or disagreement of the on-site generation with the building load profiles: it can be increased and optimised with modifications on both the energy demand and generation. In this context, the paper presents the load match analysis of a case study: a modular housing construction (it has an area of 45 m and S/V ratio equal to 2.75 m ) built in Messina (Italy). Moreover, in order to optimize the design of the next test module to be built, a parametric analysis was performed considering different scenarios on the generation side, to explore the effectiveness of the solutions sets used in current design and plan different solutions for the future ones. The results show that a 4 kWh energy storage system can increase the load cover factor by 94% (to 0.78) compared to the base case (0.41), while with only a 250 W fuel cell, the load cover factor can reach the value of 0.97.

The transition to a sustainable society and a carbon-neutral economy by 2050 requires extensive deployment of renewable energy sources that, due to the aleatority and non-programmability of most of them, may seriously affect the stability of existing power grids. In this context, buildings are increasingly being seen as a potential source of energy flexibility for the power grid. In literature, key performance indicators, allowing different aspects of the load management, are used to investigate buildings’ energy flexibility. The paper reviews existing indicators developed in the context of theoretical, experimental and numerical studies on flexible buildings, outlining the current status and the potential future perspective. Moreover, the paper briefly reviews the range of grid services that flexible buildings can provide to support the reliability of the electric power system which is potentially challenged by the increasing interconnection of distributed variable renewable generation.

The study proposes a tool developed within the TRNSYS environment aimed at integrating its building simulation features during the use phase with a Life Cycle Assessment approach. The tool can be used to investigate the relevance of each life-cycle step of the building on the primary energy consumption and global warming potential. The Life Cycle stages can be modelled with different approaches: direct input of the embodied energy and global warming potential values for each life cycle step as defined in the EN 15978, use of an internal database of embodied energy and global warming potential of construction materials and energy systems, direct connections of building simulation outputs to the tool for the use phase. The proposed component is able to model correctly the LCA of a case study, obtaining negligible deviations from the results of a LCA study performed with a state of the art LCA software (lower than 0.05% for all impacts).