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The intervention on the existing building envelope thermal insulation is the main and effective solution in order to achieve a significant reduction of the building stock energy needs. The infrared technique is the methodology of the energy diagnosis aimed to identify qualitatively the principal causes of energy losses: the presence of thermal bridges. Those weak parts of the building envelope in terms of heat transfer result not easy to treat with an energy efficiency intervention, while they are gaining importance in the buildings total energy dispersion, as the level of insulation of opaque and transparent materials is continuously increasing. It is generally possible to evaluate the energy dispersions through these zones with a deep knowledge of the materials and the geometry using a numerical method. Besides, authors proposed in the past a methodology to assess the flux passing through thermal bridges with an infrared image correctly framed. The analysis of surface temperatures of the undisturbed wall and of the zone with thermal bridge, allows to define the Incidence Factor of the thermal Bridge (Itb). This parameter is strongly affected by the thermographic image accuracy, therefore, this paper deals with the development and validation of an innovative mathematical algorithm to enhance the image resolution and the consequent accuracy of the energy losses assessment. An experimental campaign in a controlled environment (hot box apparatus) has been conducted on three typologies of thermal bridge, firstly performing the thermographic survey and then applying the enhancement algorithm to the infrared images in order to compare the Itb and the linear thermal transmittance ψ values. Results showed that the proposed methodology could bring to an accuracy improvement up to 2% of the total buildings envelope energy losses evaluated by quantitative infrared thermography. Moreover, the proposed algorithm allows the implementation of a further process applicable to the images, in order to extract the physical boundaries of the hidden materials causing the thermal bridge, so revealing itself as a useful tool to identify exactly the suitable points of intervention for the thermal bridge correction. The application of the imaging process on the quantitative infrared thermography is an innovative approach that makes more accurate the evaluation of the actual heat loss of highly insulating buildings and reaching a higher detail on the detection and treating of thermal bridges.

Household energy consumption has been increasing in the last decades, the residential sector is responsible for about 40% of the total final energy use in Europe. Energy efficiency measures can both reduce energy needs of buildings and energy-related CO2 emissions. For this reason, in recent years, the European Union has been making efforts to enhance energy saving in buildings by introducing various policies and strategies, in this context, a common methodology was developed to assess and to certify energy performance of buildings. The positive effects obtained by energy efficiency measures need to be verified, but measuring and monitoring building energy performance is time consuming and financially demanding. Alternatively, energy efficiency can also be evaluated by specific indicators based on energy consumption. In this work, a methodology to investigate the level of energy efficiency reached in the Umbria Region (Central Italy) is described, based on data collected by energy certificates. In fact, energy certificates, which are the outcomes of simulation models, represent a useful and available tool to collect data related to the energy use of dwellings. A database of building energy performance was developed, in which about 6500 energy certificates of residential buildings supplied by Umbria region were inserted. On the basis of this data collection, average energy and CO2 indicators related to the building heritage in Umbria were estimated and compared to national and international indicators derived from official sources. Results showed that the adopted methodology in this work can be an alternative method for the evaluation of energy indicators, in fact, the ones calculated considering simulation data were similar to the ones reported in national and international sources. This allowed to validate the adopted methodology and the efficiency of European policies.

Paper and cardboard, made with recovered fibers obtained by recycling, are an attractive, sustainable material. Recovered paper and cardboard are mainly used for packaging purposes, even if, in recent years, various researches focused on the possibility to develop new products and proposed alternative applications. This paper presents new designs of acoustic absorbers made of partially recycled cardboard, in order to reduce the environmental impact of the materials usually used for the acoustic correction on indoor environments. Some of these new designed absorbers are porous and make use of the visco-thermal absorption effects in the pore space. Other absorbers are based on the Helmholtz resonator principle. Computer modeling software was used to predict the performance of the absorbers; in particular, different options of cardboard-based panels and paperboard tubes were investigated to identify the solutions with the best acoustic performance. A real-size prototype of a sandwich panel was then experimentally characterized in laboratory. The absorption coefficient spectrum of the prototype was measured according to the procedure indicated in the ISO 354 standard. The results show that the measured acoustic absorption coefficient of the material made using cardboard was higher than the one of traditional gypsum absorbers, giving in particular an increase of the acoustic absorption at mid and high frequencies in the order of 40%. A Life Cycle Assessment analysis was also performed to evaluate the environmental advantages of these materials. The environmental impacts of the production of the cardboard-based panel were compared with the impacts of conventional acoustic materials. The analysis highlighted a potential reduction of both energy demand and greenhouse gas emissions during the production process of the cardboard-based acoustic materials. The estimated CED and GWP values result 10% and 34% respectively lower than the impacts of a conventional gypsum board.