• Energy Research

Climate change mitigation is a recurrent consciousness topic among society and policymakers. Actions are being adopted to face this crucial environmental challenge, with a rising concern with a big impact on the building sector. Construction materials have a high carbon footprint as well as an energy-intensive activity. To measure the environmental damage and effects, life cycle assessment (LCA) is the methodology most widespread. However, the LCA methodology itself and the assumptions done to carry it out leads to a generalized burden to compare the case studies outcomes. LCA method and for instance geographical location are incompatibilities also revealed in embodied energy and embodied carbon assessments. Urgent actions are needed to clarify the confusions arisen in the research, considering a detailed study on the embodied energy and embodied carbon values. From a material level point of view, this paper aims to illustrate the chronological overview of embodied energy and embodied carbon through keywords analysis. Moreover, to support and corroborate the analysis, an organized summary of the literature data is presented, reporting the range of embodied energy and embodied carbon values up to now. This systematic analysis evidences the lack of standardization and disagreement regarding the assessment of coefficients, database source, and boundary system used in the methodology assessment. © 2020 Elsevier B.V.

Contains fulltext : 285538.pdf (Publisher’s version ) (Open Access)

The building and construction sector is a large contributor to anthropogenic greenhouse gas emissions and consumes vast natural resources. Improvements in this sector are of fundamental importance for national and global targets to combat climate change. In this context, vertical greenery systems (VGS) in buildings have become popular in urban areas to restore green space in cities and be an adaptation strategy for challenges such as climate change. However, only a small amount of knowledge is available on the different VGS environmental impacts. This paper discusses a comparative life cycle assessment (LCA) between a building with green walls, a building with green facades and a reference building without any greenery system in the continental Mediterranean climate. This life cycle assessment is carried according to ISO 14040/44 using ReCiPe and GWP indicators. Moreover, this study fills this gap by thoroughly tracking and quantifying all impacts in all phases of the building life cycle related to the manufacturing and construction stage, maintenance, use stage (operational energy use experimentally tested), and final disposal. The adopted functional unit is the square meter of the facade. Results showed that the operational stage had the highest impact contributing by up to 90% of the total environmental impacts during its 50 years life cycle. Moreover, when considering VGS, there is an annual reduction of about 1% in the environmental burdens. However, in summer, the reduction is almost 50%. Finally, if the use stage is excluded, the manufacturing and the maintenance stage are the most significant contributors, especially in the green wall system.

Large scale mitigation strategies showed to represent promising solutions for enhancing liveability in dense urban contexts. Therefore, most of the researches are focused on assessing the effect of high albedo surfaces and greenery. The paper deals with a numerical and experimental analysis of these evapotranspiration and high-reflectance surfaces in a full scale experimental set-up where more than 20 cubicles are monitored in a Mediterranean continental climate. The experimental set-up itself covers an intermediate inter-building perspective between the lab scale and the real urban contexts, which compromises the possibility to generalize final results. This scale is able to better control geometry of area, but allows real microclimate monitoring and calibration of CFD models. Starting from a validated model, this study simulated alternative scenarios with gradually varying the presence of common mitigation strategies with the scope to evaluate their effect to this aim. Results showed that high albedo solutions best mitigate summer overheating reducing the air temperature, while greenery was more effective in the densest configurations with low albedo envelopes, showing how geometry related variables may play a key role in determining the optima configurations of microclimate mitigation strategies, also important for the best exploitation of renewables in the built environment. © 2019 Elsevier Ltd

Nature-based solutions applied to the building skin, such as green roofs and vertical greenery systems, are standing out as the most promising by contributing with thermal improvements at building scale. From previous research done by GREiA research group at the University of Lleida (Spain), energy savings up to 58% were obtained by implementing vertical greenery systems on external building walls for cooling purposes. However, since there exist other passive and active energy saving technologies in the literature review that were limited their cooling and heating capacity after implementing internal heat loads, new experimental tests for two different vertical greenery systems simulating the heat loads in both, summer and winter were conducted in this research. Additionally, these experiments also improve the scarce and controversial literature for winter conditions. The results demonstrated that considering internal loads in experimental investigations is crucial for the results of the effectiveness of the green walls and green facades. The energy savings of VGS were reduced between 22.5% and 26.7% because of the internal loads for cooling purposes, and increased about 3.6% and 3.1% for heating. © 2019 Elsevier Ltd

Life cycle assessment (LCA) and life cycle costing (LCC) are innovative tools based on an innovative approach allowing to investigate the environmental and economic burdens of a product or service throughout its lifecycle. Although usually carried out individually, their integration in a comprehensive analysis could provide a substantial asset in every kind of decision-making procedures. In this study, the sustainability of a newly developed component for refrigeration units is investigated by applying these two tools in a cradle to grave approach in different scenarios. Results from the LCA show the huge impact associated with the manufacturing process of the kit compared to the transport. However, the use phase environmental analysis showed an environmental payback period always lower than 10 years. Results from the LCC show that the initial investment cost represents the highest share for the final user. Furthermore, favourable discounted payback periods are generally found, leading to net savings above 270,000 € in the case best-case scenario. © 2021 Elsevier Ltd

The construction industry is one of the less sustainable activities on the planet, constituting 40% of the total energy demand and approximately 44% of the total material use and the generation of 40–50% of the global output of greenhouse gases. The biggest environmental impact caused by buildings is generated during their operational phase due to the energy consumption for thermal conditioning. Hence, in order to reduce this energy consumption, insulation materials must be used and from a life-cycle perspective, the use of insulation materials reduces the building impact over time. This paper develops a comparative life cycle assessment (LCA) of different insulation materials (polyurethane, extruded polystyrene, and mineral wool) to analyse the environmental profile of each insulation material type in the Mediterranean continental climate. Significantly, all three insulation materials demonstrated a net positive benefit over a fifty-year life span due to the reduced heating requirements of the building. Results showed that the highest environmental impact was associated with the polystyrene insulation material and the best environmental performance was for the mineral wool. Moreover, regarding the consumption, polyurethane and mineral wool had similar thermal performance during the whole year. Furthermore, the environmental payback period shows that the cubicles with insulation material are environmentally efficient, if they are used for at least 7 years (for mineral wool), 10 years (polyurethane), and 12 years (extruded polystyrene). The results of this research give new insights into the effect on building insulation materials. © 2020 Elsevier B.V.

Urban green infrastructure (UGI) and nature-based solutions (NBS) are increasingly recognized as strategies to address urban sustainability challenges. These solutions are attracting key scientific and marketing attention thanks to their capability to improve indoor and outdoor thermal comfort and environmental quality of spaces. In urban areas, where most of the population worldwide lives, indoor-outdoor environmental quality is compromised by local and temporary overheating phenomena, air pollution concentration, and impervious surfaces minimizing urban space resilience to climate change related hazards. In this view, the proposed study concerns the analysis of a greenery system for enhancing outdoor thermal conditions and local warming mitigation for pedestrians for the continental Mediterranean climate. The system has the purpose of designing an outdoor “alive” shading system to be applied in open public spaces, with producing physical and societal benefits. The experimental results showed that the implementation of the greenery, characterized by lower surface temperatures and evapotranspiration compared to a simple pergola system, allows the reduction of outdoor air temperature under the shading system and, thus, higher relative humidity in summer. Specifically, the hygrothermal cooling and the additional shading thanks to the presence of greenery provide local air temperature reduction up to 5 °C at pedestrian level.