Durability of technologies in the keeping of ZEB's performances

Abstract Durability is an important aspect that has not to be neglected in ZEB design. The requirements for buildings energy needs reduction and increase of renewable energy sources stimulated designers to integrate technologies in an efficient way. This ambitious goal must meet the capacity of the technical solutions to guarantee their performances over the years. The durability of materials and technologies is a topic that warrants further analyses in order to assess the proper efficiencies and the expected lifetime of a ZEB. Typically the energy balance of a ZEB is calculated by considering the annual energy flows or rarely the whole life cycle. The most used approaches consider constant performance of materials and technical elements over the lifespan. However, the performance loss of a single element can cause an imbalance in the behavior of a ZEB, for which persists a thin balance between inlet and outlet flows. The paper provides a critical point of view on this issue paying attention on the following technical solutions implemented in a case study for which the current scientific literature provides analysis on the degradation during their lifetime: glazing systems, VIPs, PV panels and GSHPs

Estimation of building energy performance for local energy policy at urban scale

Abstract Cities play a key role in sustainability policies aimed at reducing environmental impacts and increasing energy efficiency in the building sector. At urban level, the analysis models are split in bottom-up and top-down types as a function of the methodological approach of input data processing, aggregated in the first case and disaggregated in the second one. The present paper describes the methodological approach adopted for the implementation of a bottom-up model able to estimate the energy performance of buildings and to define an energy diagnosis process at urban scale. Starting from the information provided by tools available at the Public Authorities and at the most relevant statistical studies on the national energy market, the model provides an estimation of the energy consumption and performance of buildings. The model is applied to a real district of Bologna and the derived spatial database allows the energy performances of buildings to be mapped

Application of IoT and Machine Learning techniques for the assessment of thermal comfort perception.

Abstract Thermal comfort is traditionally assessed by using the PMV index defined according to the EN ISO 7730:2005 where the user passively interacts with the surrounding environment considering a physic-based model built on a steady-state thermal energy balance equation. The thermal comfort satisfaction is a holistic concept comprising behavioral, physiological and psychological aspects. This article describes a workflow for the assessment of the thermal conditions of users through the analysis of their specific psychophysical conditions overcoming the limitation of the physic-based model in order to investigate and consider other possible relations between the subjective and objective variables

Refurbishment design through cost-optimal methodology: The case study of a social housing in the northern Italy

The energy retrofit of social housing buildings in Italy is a big challenge, for their poor energy performance and their large diffusion, but it is affected by several problems mainly due to lack of funds. Therefore, a solid methodological base to achieve optimal energy levels, considering the best balance with the costs, can be useful for a cheaper approach to their energy performance improvement. The cost optimal methodology indicated by the European Directive 2010/31/UE is here applied on a social housing building, located in the northern Italy, in order to demonstrate how it can be used as a supporting decision tool for refurbishment interventions on existing residential buildings, when limited investments from Public Authorities or privates are involved. A series of energy efficiency measures are defined in order to identify different improvement scenarios, related both to the envelope and to the technical systems. After a first step calculating the primary energy consumption and the Global Cost in accordance with the EN 15459:2007, the best costs/benefits ratio is evaluated among all the hypothesized scenarios. The results of the research are expected to be a stimulus for the definition of specific refurbishment plans for the energy efficiency increase of social housing

A procedure to evaluate the most suitable integrated solutions for increasing energy performance of the building\u2019s envelope, avoiding moisture problems

General guides to support the refurbishment design indicate separately the solutions to common problems such as thermal loss, interstitial condensation, sound transmission, fire safety etc. This paper deals with combined solutions that take into account simultaneously two of these aspects, aiming both at reducing thermal losses and at avoiding or limiting problems related to moisture transfer and condensation, jointly with an indispensable cost analysis. Improving the energy performance of buildings should start from the evaluation of the building\u2019s envelope energy-saving options. The subject of the research is oriented to typical buildings, often critical from the energy standpoint, which are represented by social housings. The refurbishment target should be the NZEB model, even if it is very difficult to find suitable general solutions. As the renovation design process depends also on the sustainability of costs, an evaluation procedure, previously proposed, is widened to take into account this aspect, by considering characteristics and constraints, and assuring reasonable costs for the most suitable solutions. The methodology has been applied to a case study represented by a common building unit. The insulation improvement is made through a choice of the most suitable combination of material and thickness, with the aim not only of the energy saving, but also of the reduction of the risk of vapour condensation that depends, among other things, on the position of the insulating materials within the wall\u2019s structure. Some combined refurbishment solutions for the building envelope are examined and the corresponding costs are evaluated. Moreover, to show the importance of the problem in mild and continental climates, a comparison of the results in different climatic conditions is presented

Analysis and definition of a ZEB building at optimum level of efficiency and costs

The urban regeneration actions arise by the growing importance of information and communication technologies, moving to sustainable solutions, energy saving and security. New energy planning tools are adopted suggesting the legislator towards large-scale energy policies, by setting up all the information related to the building fabric whose representativeness can be defined through Reference Buildings. The aim of this study is the definition of a suitable methodology based on an energetic and economic approach able to detect refurbishment scenarios of existing buildings, in compliance with the ZEB requirements. For this purpose two residential reference buildings, located in Milan and Reggio Calabria representative of different climatic conditions, are defined aimed at analyzing the energy saving and the CO2 reduction of a series of refurbishment scenarios. Ten energy improvement packages, related both to the envelope and to the technical systems, are considered for the achievement of NZEB and ZEB target. Among these technologies, the best solutions are selected from an energy and economic point of view. Finally, the results are applied to the Italian buildings stock with the same characteristics of the reference building, through a simplified bottom-up approach

Cardiac Imaging for the Assessment of Left Atrial Mechanics Across Heart Failure Stages

The left atrium (LA) is emerging as a key element in the pathophysiology of several cardiac diseases due to having an active role in contrasting heart failure (HF) progression. Its morphological and functional remodeling occurs progressively according to pressure or volume overload generated by the underlying disease, and its ability of adaptation contributes to avoid pulmonary circulation congestion and to postpone HF symptoms. Moreover, early signs of LA dysfunction can anticipate and predict the clinical course of HF diseases before the symptom onset which, particularly, also applies to patients with increased risk of HF with still normal cardiac structure (stage A HF). The study of LA mechanics (chamber morphology and function) is moving from a research interest to a clinical application thanks to a great clinical, prognostic, and pathophysiological significance. This process is promoted by the technological progress of cardiac imaging which increases the availability of easy-to-use tools for clinicians and HF specialists. Two-dimensional (2D) speckle tracking echocardiography and feature tracking cardiac magnetic resonance are becoming essential for daily practice. In this context, a deep understanding of LA mechanics, its prognostic significance, and the available approaches are essential to improve clinical practice. The present review will focus on LA mechanics, discussing atrial physiology and pathophysiology of main cardiac diseases across the HF stages with specific attention to the prognostic significance. Imaging techniques for LA mechanics assessment will be discussed with an overlook on the dynamic (under stress) evaluation of the chamber

Abdominal obesity phenotype is associated with COVID-19 chest X-ray severity score better than BMI-based obesity

Chest X-ray (CXR) severity score and BMI-based obesity are predictive risk factors for COVID-19 hospital admission. However, the relationship between abdominal obesity and CXR severity score has not yet been fully explored. This retrospective cohort study analyzed the association of different adiposity indexes, including waist circumference and body mass index (BMI), with CXR severity score in 215 hospitalized patients with COVID-19. Patients with abdominal obesity showed significantly higher CXR severity scores and had higher rates of CXR severity scores ≥ 8 compared to those without abdominal obesity (P < 0.001; P = 0.001, respectively). By contrast, patients with normal weight, with overweight and those with BMI-based obesity showed no significant differences in either CXR severity scores or in the rates of CXR severity scores ≥ 8 (P = 0.104; P = 0.271, respectively). Waist circumference and waist-to-height ratio (WHtR) correlated more closely with CXR severity scores than BMI (r = 0.43, P < 0.001; r = 0.41, P < 0.001; r = 0.17, P = 0.012, respectively). The area under the curves (AUCs) for waist circumference and WHtR were significantly higher than that for BMI in identifying a high CXR severity score (≥ 8) (0.68 [0.60-0.75] and 0.67 [0.60-0.74] vs 0.58 [0.51-0.66], P = 0.001). A multivariate analysis indicated abdominal obesity (risk ratio: 1.75, 95% CI: 1.25-2.45, P < 0.001), bronchial asthma (risk ratio: 1.73, 95% CI: 1.07-2.81, P = 0.026) and oxygen saturation at admission (risk ratio: 0.96, 95% CI: 0.94-0.97, P < 0.001) as the only independent factors associated with high CXR severity scores. Abdominal obesity phenotype is associated with a high CXR severity score better than BMI-based obesity in hospitalized patients with COVID-19. Therefore, when visiting the patient in a hospital setting, waist circumference should be measured, and patients with abdominal obesity should be monitored closely. Level of evidence Cross-sectional descriptive study, Level V