• Energy Research

Abstract The spread of nearly zero-energy buildings (nZEB) currently reflects the European Commission’s first policy step in fighting climate change through the construction sector. This paper analyses the design criteria and thermodynamic behaviour of an nZEB building in a Mediterranean climate and how its various properties affect its final energy consumption. The case study is a single-family dwelling of 309 m2 located in Mesagne, a small city in South Italy (Apulia, BR). Using DesignBuilder software, a dynamic simulation of the overall building-plant system performance estimated the building’s hygrothermal comfort and the energy consumption of air conditioning. Monitoring of in-field energy consumption and production validated the building performance simulation model and evaluated its performance gap. Subsequently, a parametric analysis of various scenarios assessed the impact on total energy consumption of different plant system configurations and a bioclimatic criterion adopted in the building: one without earth-to-air heat exchanger, one without heat recovery and recirculation and one without sunscreens. This research shows how a passive building design combined with the use of an efficient plant system can easily meet the nZEB requirements with high performance in terms of energy consumption and indoor thermal comfort.

The European Community has prioritized reducing energy consumption and improving energy efficiency in the building sector, along with ensuring increasingly high standards of thermal comfort, as key goals over recent decades. Given the impact of climate change, the rising frequency of extreme weather events, and the rapid shifts in peak demand during both winter and summer, buildings must efficiently respond to sudden and extreme temperature fluctuations while maintaining optimal indoor comfort. Phase-change materials (PCMs), which can adapt their thermophysical properties in response to external conditions, may offer a solution for enhancing building resilience to climate change. This paper evaluates the benefits of integrating various PCMs with plasterboard in the energy retrofit of a multi-family complex in a Mediterranean climate. The study examines the application of a PCM with a melting temperature of 25 °C at three different thicknesses (74.2 mm, 37.1 mm, and 20.8 mm) to external walls, ceilings, and both walls and ceilings simultaneously. Among the various applications, using the PCM on walls alone maximized heating savings as thickness increased (26.6%), while ceiling application maximized cooling energy savings (17.5%). Combined solutions offered the most balanced seasonal benefits, leading to the greatest overall energy reductions (24.1%).

In the present paper a new and innovative way to approach the regeneration of public buildings and public housing is proposed. It consists in a dissipative steel frame to reduce the displacement demand and to improve the energy efficiency of a real existing structure, inserting buckling-restrained axial dampers (BRAD) type dissipative braces. This system is adaptable to any construction made of reinforced concrete frames and improves energy efficiency and earthquake-resistant performance; moreover, it upgrades the aesthetics of buildings and the quality of life for the users. In fact, the system is capable of assuming different and pleasant architectural shapes offering benefits in terms of earthquake-resistant performance, energy saving, and energy production from renewable sources. The attention to the aesthetic results renders the intervention a redevelopment strategy not only on an architectural scale, but also in the urban contexts for degraded and marginalized suburbs. The performances of the proposed kit were evaluated on a case study consisting in a social house located in the south of Italy. Numerical analyses have been carried out and the results have been reported both from the seismic protection and energy efficiency points of view. As a result, the produced renewable energy from the retrofitting system and the building seismic capacity increased. A rapid and precise control process, able to return a suitable structural dimensioning of the frame, according to the different application contexts, is finally proposed.

Abstract Among Mediterranean historical buildings, the Andalusi architecture is the result of an intuitive and experimental process of adaptation to the surrounding environment. The medieval Muslims coped with difficult climatic conditions in al-Andalus through passive cooling strategies, paying attention also to the thermal comfort. The paper focuses, in particular, on natural ventilation in the Infants’ Tower in the Alhambra of Granada. It has eight mashrabiyas at the top whose performance is investigated through a CFD model, in order to understand their contribution to the improvement of indoor thermal comfort and rational energy use during summer.

Abstract Traditional passive cooling strategies are a very important tool in Mediterranean architecture to face climate changes and to limit energy consumption, both in new and ancient buildings, toward sustainability and reduction of fossil fuel consumption. Starting from the traditional architectural culture, the aim of the study is to understand how using and re-interpreting ancient constructive elements that interact with the outdoor environment, in order to assure the indoor thermal-hygrometric comfort. In this regard, the paper proposes the study of a new system of wooden lattice openings to be installed in Mediterranean buildings. It originates from the Islamic architecture and it is used especially to control natural light into the buildings. Actually, it has also the function to regulate the airflow into the indoor environment, mitigating the climate conditions and ensuring the comfort of inhabitants. For this reason, the research proposes the analysis of this system through modern computational tools and demonstrates that it can guarantee better indoor summer conditions, improving wind velocity and air change rate in the room.

Proper design of the ventilation system is strategic to achieve nearly zero energy building (NZEB) target while providing high IAQ standards. This paper investigates a multi-family complex of eight dwellings NZEB in Italy built on a former industrial shed. The planned HVAC system foresees the combined use of primary ventilation with fan-coil units fed by ground source heat pumps. Three hybrid ventilation strategies are compared to evaluate the potential cooling energy saving: the first one explores the use of an earth-to-air heat exchanger (EAHX), the second one proposes night hybrid ventilation from 10 p.m. to 6 a.m., and the last one analyzes the implementation of free cooling mode in mechanical ventilation. Cooling energy saving, thermal comfort, CO2 reduction and cost-effectiveness of three approaches comparing with the base case were evaluated. EAHX generatesa cooling energy saving of 20.7%. Combined use of night ventilation with mechanical ventilation system reduces the cooling energy demand by 14.4%, while free cooling produces a less effective decrease in the electricity consumption of 7.7% only. Moreover, the influence of climatic conditions on hybrid ventilation strategies efficiency is assessed in three cities. This analysis shows that EAHX is the hybrid ventilation strategy which produces the greatest energy saving in all Italian climatic zones showing an energy saving from 33.7% in Milan to 9.8% in Palermo. Free cooling and night ventilation generate more benefits in the middle-season when lower minimum outdoor temperatures occur.

This paper presents the energetic and economic analysis of a virtuous example consisting of a tri-generation system fuelled only with olive tree pruning residues and planned to be located next to Bari Airport (Apulia, Italy). The main goal is to demonstrate the feasibility and convenience of producing cooling, heating and electrical power from olive tree pruning residues in those regions characterized by a high availability of this kind of biomass, such as Apulia. A strategic location was selected, namely Bari Airport (Apulia), and this paper demonstrates the economic convenience of installing a commercially available Organic Rankine Cycle (ORC) unit of 280 kWe that is capable of satisfying the thermal demands of the airport, with the addition of an absorption chiller for air conditioning in the airport buildings. First it is verified that the quantity of oil tree pruning residues available in the area surrounding the airport fully can satisfy the plant demand of feedstock. Then a detailed description of the components of the plant is provided. The performance of the plant is therefore evaluated in order to assess the thermodynamic competitiveness of a tri-generative system fuelled with this type of biomass. Finally, a detailed economic analysis is carried out with the aim of demonstrating the advantages that the plant can assure in terms of payback period (PBP), net present value (NPV) and internal rate of return (IRR). Two different typologies of government incentives are considered. In both of which, the PBP is 6 years with an IRR of about 21% and this points out the great economic attractiveness of the project. From an ecological point of view, the plant can ensure a remarkable reduction in CO2 emissions.