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The energy consumption necessary to maintain thermal comfort in buildings remains a significant and partially unjustified part, accounting for about 30–40% of the total energy consumption. Despite the increasingly pressing regulations in the energy sector (EPBD recast), the quality of the internal environment remains one of the critical parameters on which to pay more attention in view of a consistent evaluation of the Nzeb building. The windowed components are often designed with thermal insulation performances higher than the minimum requirements but still they lack in design of the incident solar radiation control, which is a particularly delicate topic for indoor comfort and more generally for a higher energy efficiency in buildings. If we think of the numerous variables of influence (typology, orientation, geographical location, etc.), the possibilities to associate energy saving, lighting control and users’ comfort are inevitably entrusted to dynamic systems integrated into the glass. In this paper authors present the results related to the experimental characterization of two identical test rooms with different typologies of windows. One room is furnished with a traditional high thermal performance glass and the other, with an electrochromic glass suitably controlled by remote. The operative temperature measured in both test rooms have been utilized to verify the simulation model developed to assess the energy saving achievable in a Mediterranean climate, taking properly into account the hourly variations of the climate and the actions on the shading regulation systems.

The building sector is known to have a significant environmental impact, considering that it is the largest contributor to global greenhouse gas emissions of around 36% and is also responsible for about 40% of global energy consumption. Of this, about 50% takes place during the building operational phase, while around 10–20% is consumed in materials manufacturing, transport and building construction, maintenance, and demolition. Increasing the necessity of reducing the environmental impact of buildings has led to enhancing not only the thermal performances of building materials, but also the environmental sustainability of their production chains and waste prevention. As a consequence, novel thermo-insulating building materials or products have been developed by using both locally produced natural and waste/recycled materials that are able to provide good thermal performances while also having a lower environmental impact. In this context, the aim of this work is to provide a detailed analysis for the thermal characterization of recycled materials for building insulation. To this end, the thermal behavior of different materials representing industrial residual or wastes collected or recycled using Sardinian zero-km locally available raw materials was investigated, namely: (1) plasters with recycled materials; (2) plasters with natural fibers; and (3) building insulation materials with natural fibers. Results indicate that the investigated materials were able to improve not only the energy performances but also the environmental comfort in both new and in existing buildings. In particular, plasters and mortars with recycled materials and with natural fibers showed, respectively, values of thermal conductivity (at 20 °C) lower than 0.475 and 0.272 W/(m⋅K), while that of building materials with natural fibers was always lower than 0.162 W/(m⋅K) with lower values for compounds with recycled materials (0.107 W/(m⋅K)). Further developments are underway to analyze the mechanical properties of these materials.

It is now known that the use of Building Information Modeling (BIM) procedures offers many benefits in the design and management of buildings. According to recent legislative enactments the BIM procedures will become mandatory for Public Works as from 2019. There are several advantages by using BIM procedures, among them the following can be highlighted: gaining a clear overview of the building plant system, evaluating the spatial coherence of the plant networks, the evaluation of the interferences to keep the system do not interfere with the functionality or the aesthetics of built environments. The present work analyzes the BIM procedures with particular reference to air conditioning systems in existing buildings, to their performance and management characteristics. The objective consists of analyzing the different BIM procedures and critically comparing the information provided by the IFC standard published by the European Institution Building SMART International, recognised as a standard by ISO, with the main reference standards for building installations and facilities design.

In this paper an original simulation and optimization model for flat solar collector coupled with a flat bottom reflector has been developed. The problem of simulation and optimization for such system is essential in order to find the proper configuration of the reflector able to obtain the expected maximum efficiency of the whole system. The proposed simulation model analytically determines the solar energy on the collector-reflector system and therefore the optimization model estimates the optimal values of the design parameters. A new comprehensive formulation of the shadowing and irradiating level on the collector, able to take into account the finite length geometry with variable dimensions, is presented. The number and the value of the angular positions, the time periods over which the angular positions should be adjusted, the size, the aspect ratio, between the length and the width of the reflector, and the overhangs are parameters treated simultaneously with a global optimization procedure. The model is integrated with an original scheme of optimization where energetic and economic aspects are both taken into account. The simulations results of the study reveal the optimal number of angular adjustments per year, the existence of a small optimal neighborhood of the aspect ratio and the optimal size of the reflector, for which the maximum reduction of the payback time of the augmented system compared to its reference collector is achieved. The results presented in the study are related to the solar data of Italian latitude, but they can be easily extended for any geographical location.

Building materials are usually characterized in stationary or almost-stationary conditions and mono dimensional heat flow regime. The existing standards (such as ISO 9869 or EN ISO 6946, EN 12664, EN 12667, ISO 8302 etc), require experiments carried out in steady-state conditions, with a very fine control of the measuring parameters with the aim to apply a simple and reproducible procedure for the determination of thermal properties. However, the thermodynamic conditions that lead to a steady-state operating mode and mono dimensional flow are very difficult to obtain (in real conditions) or very expensive and time consuming (in climate chambers). In this paper the authors present the development of a method for thermal characterization of building components, inferring the steady-state conditions, when only measures in transient conditions are available. The method, based on an adaptive linear neural network (ALNN) model also could be have the potentialities to determine the thermal diffusivity from a significant transient behavior ad hoc imposed. The study targets multilayered walls homogeneous and the results are compared with the experimental data measured by a climate chamber that operate according to the standard EN 12667

Building Information Modeling (BIM) is a process with an increasing diffusion in the construc-tion market that leads to considerable savings in realization times and building management costs. The BIM also allows interchange of data for interoperability between various computer applications for the most varied purposes and uses (management, monitoring, performance cal-culation). Consequently, application of Building Performance Modeling (BPM), that is the use of BIM models for calculating the performance of the building, is becoming an important aspect of building design. The purpose of this paper is to analyze the information contained in BIM da-ta structure that can be used to design or to evaluate, through field measurements, compliance with acoustic classes or, in general, the acoustic performances of a building. Nevertheless, the analysis of IFC (Industrial Foundation Classes) data format, developed by BuildingSMART and associated with BIM as open standard for sharing data, highlights some benefits and some shortcomings for application in building acoustic field. In this work the BIM process for the de-sign and performance evaluation of a building made according to the CLT construction system is shown, pointing out thepotential and the limitations of this method. Finally, field measure-ments were carried out to verify the calculated acoustic performances and to evaluate the relia-bility of these tools for supporting acoustic design of buildings.

This study will assess the influence on the acoustic insulation of facade of small elements such as ventilation holes or mechanical ventilation systems. These elements are present to ensure an appropriate air exchange, and they can be with or without heat recovery units. The noise insulation of facade, taking into account such ventilation holes, was evaluated starting from the calculations carried in accordance with the procedures laid down by the standard EN 12354 and performing measurements concerning specific case studies.

Development of technologies, materials, support systems, and coatings has made the integration of solar thermal systems into the building envelope increasingly possible. Solar thermal collectors can either be directly integrated, substituting conventional roof or façade covering materials, or constitute independent devices added to a roof or façade structure. Aimed at estimating the real effectiveness of building-integrated solar systems for domestic heat water (DHW) production or for heating integration, when horizontal or inclined pitches on buildings are not applicable, the authors analyze a case study with different scenarios, taking into account the issues connected to a highly urbanized context in the Mediterranean climate. A GIS model was used for estimating the energy balance, while the real producibility of the simulated systems was calculated by a dynamic hourly simulation model, realized according to ISO 52016. The savings in terms of primary energy needs obtained by installing solar thermal systems on the facade are presented, and the differences between the cases in which the system is used for DHW production only and for space heating too are distinguished and discussed. The evaluated potential is quantified in the absence of roof collectors, despite their high potential in the Mediterranean region, in order to better appreciate the effects induced by integrated facade systems.

This work proposes the application of a new simulation method based on fractal geometry for the calculation of the thermal conductivity for building materials. The results obtained are compared with the measurement, in a climatic chamber, of the heat flow through a material chosen as the sample. The test sample is made with “pietracantone”, a stone widely used as a building material and as an ornamental stone in the areas of Cagliari and Sassari in Sardinia. This material is characterized by a limestone matrix and a porosity which significantly influences the value of thermal conductivity. It is not known to the authors that this material had already been studied for its thermal properties.

In this study a theoretical analysis of a collector augmented by a bottom booster reflector is presented. An analytical model has been developed and used to estimate the solar irradiation passing through the transparent cover of a flat collector, both with and without a bottom reflector. The analytical model is based on the anisotropic sky model and takes into account a finite length system with different angular configurations and reciprocal shading and reflections between reflector and collector. Computer simulations have been carried out in order to find the optimum angles of the reflector with respect to the plane of the collector. Optimal inclinations of the collector and reflector for each month at 39° N latitude have been identified.

This paper considers the energy analysis of a heat pump system coupled to the ground by means of vertical exchangers, to verify which thermodynamic boundary conditions, in terms of thermal conductivity and diffusivity of the ground and the grout, make it competitive in comparison with other technologies harnessing atmospheric air as the heat source. The comparison is based on the maximum theoretical efficiency available in correspondence to the temperature effectively assumed by the thermal energy reservoirs in contact with the evaporator and the condenser during the operating conditions. The comparison of the two sources/sinks of heat, i.e. the ground and atmospheric air, represents the comparison between the time trend of the exergy of the two reservoirs required by an ideal GSHP and ASHP respectively. A fully transient heat transfer model able to handle on a time scale of a year or more and with a refinement of less than an hour is considered, since short term variations have significant effects on the overall performance of GSHP. In this paper the borehole heat transfer problem in the Laplace domain is solved for any trend and duration of thermal loads, taking into account an existing analytical approximation model of the full solution proposed by Lamarche and Beauchamp. A numerical inversion using the Inverse Discrete Fourier Transform is then applied to obtain the time domain solution. The method combines the flexibility and accuracy of the analytical model with the superior efficiency of the computational time offered by the numerical inversion if compared with that of methods based on the convolution scheme.

Predictive methods for the estimation of acoustic performance in buildings are largely used at building design stage. The sound insulation capacity of numerous constructive systems are well known through a process of analysis that starts from laboratory measurements of sound insulation and flanking transmission of airborne and impact sound of building elements, in order to obtain input data for predictive methods, and ends with field measurements for the validation of the estimation process and, possibly, for the compliance with the building requirements. Nowadays, Cross-Laminated Timber technology is fast becoming the preferred constructive system for many buildings, thanks to its flexibility and speed of build along with its ability to achieve a greater number of storeys than traditional timber frame. On the other hand, for this construction technology the input data for the prediction methods are often not available and extensive research on the validation of numerical methods for the estimation of acoustic performances have not yet been carried out due to the relatively small market share of CLT in building industry. During independent research, carried out recently by the Universities of Cagliari, Bologna and Padova, it was possible to apply a complete process of evaluation, prediction and estimation of the acoustic performances of timber buildings made with CLT structures. A large set of data from laboratory measurements of CLT building elements carried out in accordance with standards of ISO 10140 and ISO 10848 series was applied to the recently revised ISO 12354 prediction method for the acoustic design of several residential buildings. Then, field measurement were carried out according to standards of ISO 16283 series to estimate the accuracy of the prediction and, in some cases, the influence of laying techniques and workmanship on expected results.

On the wake of the results obtained so far at the SPARC_LAB test-facility at the Laboratori Nazionali di Frascati (Italy), we are currently investigating the possibility to design and build a new multi-disciplinary user-facility, equipped with a soft X-ray Free Electron Laser (FEL) driven by a ∼ 1 GeV high brightness linac based on plasma accelerator modules. This design study is performed in synergy with the EuPRAXIA design study. In this paper we report about the recent progresses in the on going design study of the new facility. On the wake of the results obtained so far at the SPARC\_LAB test-facility at the Laboratori Nazionali di Frascati (Italy), we are currently investigating the possibility to design and build a new multi-disciplinary user-facility, equipped with a soft X-ray Free Electron Laser (FEL) driven by a $\sim$1 GeV high brightness linac based on plasma accelerator modules. This design study is performed in synergy with the EuPRAXIA design study. In this paper we report about the recent progresses in the on going design study of the new facility.

This paper deals with the problem to derive a marginal condition for the onset of spontaneous thermoacoustic oscillations of a gas in a circular tube, subject to a variable shape of the temperature gradient along the side wall, with one end rigidly closed and the other closed by a piezoelectric element converter. In this study the acoustic impedance of the piezo element is arbitrary in order to achieve marginal conditions between those exhibited with rigidly closed end, and those with end opened onto free atmosphere. Moreover, marginal condition is outlined adopting a variable shape of the temperature gradient with respect to the position of the stack along the tube. The marginal condition is provided at the same time with respect to variable piezo-impedance and variable position of the acoustic driver. The solution includes all dissipative effects related to the compressive and shear viscosity and the heat transmission in the boundary layer at the side wall and end wall. The formulation is given in the framework of the linear theory and the first order theory in the ratio of a boundary layer thickness to the tube radius.

In G. Pernigotto, F. Patuzzi, A. Prada, V. Corrado, & A. Gasparella (Eds.), Building Simulation Applications BSA 2017 (pp. 479–486).

The guidelines of the European community towards a low-carbon economic society identify one of the most important scenarios in the energy efficiency of existing buildings. The discrepancy between the requirement and availability of free heat (endogenous heat, solar radiation) in certain hours of the day and operating conditions, makes the steady-state hypothesis generally inappropriate. In particular, the oscillating component of the transmitted flow, compared to the average temperature difference, is regressive in winter and dominant in summer. From this it follows the reliability of the stationary forecast models in winter and the need for dynamic forecast models in summer. The dominance of the continental climate in the EU, compared to the Mediterranean one, led to the actual delay in the development of dynamic models, especially at a regulatory level. In this paper, a methodology for assessing the dynamic properties of a building component is evaluated. The methodology, based on heat transmission equations implements a numerical model for existing building components whose input data can be obtained from experimental measurements. The developed model has been used to estimate the energetic and thermal behaviour of a building envelope subjected to energy efficiency measures.