Papers by dario ambrosini
Materiales De Construccion, Aug 23, 2016
Up to now, infrared thermographic approaches have been considered either passive or active. In th... more Up to now, infrared thermographic approaches have been considered either passive or active. In the latter case, the heat flux is historically attributed to a non-natural heat source. The use of the sun has recently been incorporated into the active approach thanks to multi-temporal inspections. In this paper, an innovative hybrid thermographic (HIRT) approach is illustrated. It combines both the time component and the solar source to obtain quantitative information such as the defect depth. Thermograms were obtained by inspecting the facade of the Santa Maria Collemaggio church (L'Aquila, Italy), whereas quantitative results related to the sub-superficial discontinuities were obtained thanks to the use of advanced techniques. Experimental results linked to passive approach (i.e., the mosaicking procedure of the thermograms) performed by selecting a set of historic churches are also included in order to explain, when and where, the hybrid procedure should be used.
Energetic performance analysis of a commercial water-based photovoltaic thermal system (PV/T) under summer conditions
Journal of Physics: Conference Series, 2017
In the last years, the importance of integrating the production of electricity with the productio... more In the last years, the importance of integrating the production of electricity with the production of sanitary hot water led to the development of new solutions, i.e. PV/T systems. It is well known that hybrid photovoltaic-thermal systems, able to produce electricity and thermal energy at the same time with better energetic performance in comparison with two separate systems, present many advantages for application in a residential building. A PV/T is constituted generally by a common PV panel with a metallic pipe, in which fluid flows. Pipe accomplishes two roles: it absorbs the heat from the PV panel, thus increasing, or at least maintaining its efficiency; furthermore, it stores the heat for sanitary uses. In this work, the thermal and electrical efficiencies of a commercial PV/T panel have been evaluated during the summer season in different days, to assess the effect of environmental conditions on the system total efficiency. Moreover, infrared thermographic diagnosis in real time has been effected during the operating mode in two conditions: with cooling and without cooling; cooling was obtained by natural flowing water. This analysis gave information about the impact of a non-uniform temperature distribution on the thermal and electrical performance. Furthermore, measurements have been performed in two different operating modes: 1) production of solely electrical energy and 2) simultaneous production of thermal and electrical energy. Finally, total efficiency is largely increased by using a simple solar concentrator nearby the panel.
A comparison between thermographic and flow-meter methods for the evaluation of thermal transmittance of different wall constructions
Journal of Physics: Conference Series, 2015
One of the key parameters that "meter" the energy performance of the whole structure of... more One of the key parameters that "meter" the energy performance of the whole structure of buildings is the thermal transmittance.This parameter can be evaluated with a theoretical approach, regulated by standard ISO 6946, once the stratigraphy of the envelope and the properties of the constituent materials are known, or by using a heat flow meter (HFM), following the recommendations provided in standard ISO 9869.Recently, the use of quantitative IR Thermography (IRT) has been proposed by several researchers; this method allows to determine the overall transmittance of an envelope in a short time (especially in comparison with HFM method). However, the theoretical or experimental transmittance, measured on real buildings having walls composed by different materials, can be rather distant from those calculated or measured with different procedures.For this reason, for a correct certification of the thermal performance of a building envelope, it is necessary the availability of experimental procedures for a direct and reliable evaluation of the thermal transmittance, suitable for different walls.Research has found that, especially in historical constructions, faults in the building envelope and the age of the materials can greatly affect the HFM measurements.The aim of this work is to analyze in situ the thermal performance of three different walls which have been selected according to: different materials, different age, and different construction. On each envelope, a comparison between U-values, measured by HFM and IRT, and computed according the standard procedure, has been effected.
Energies, Nov 28, 2023
The main objective of this review is to summarize and thoroughly investigate the most popular and... more The main objective of this review is to summarize and thoroughly investigate the most popular and promising BIM (building information modeling) and BEM (building energy modeling) interoperability strategies employed in the last years (2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015)(2016)(2017)(2018)(2019)(2020)(2021)(2022)(2023), highlighting pros and cons of each strategy and trying to understand the reason for the still limited BIM-BEM interaction. This review summarizes the main countries, areas, modeling tools, and interoperability strategies, with the advantages and disadvantages of each one. The methodology is based on the PRISMA protocol, and two databases were used for the research: Scopus and Google Scholar. A total of 532 publications were selected and 100 papers were deemed useful for the purposes of this review. The main findings led to the identification of four different interoperability strategies between BIM and BEM tools: (1) real-time connection; (2) standardized exchange formats and middleware corrective tools; (3) adherence to model view definitions; (4) proprietary tool-chain. These strategies were found to be characterized by different degrees of complexity, time required for information exchange, proprietary or opensource software, ability to reduce information loss, and detailed energy results. The results of this study showed that, to date, there is no better interoperability strategy, and that further efforts are needed so that interoperability between the two tools can become commonplace.
Buildings
Over the years, the building envelope has evolved from a protective barrier element to a complex ... more Over the years, the building envelope has evolved from a protective barrier element to a complex filter system capable of optimizing the interactions between the external and internal environments. An efficient envelope reacts flexibly to variable external conditions, minimizing heat losses in the winter season. Therefore, insulating materials play a fundamental role in building’s thermal performance. In this scenario, Additive Manufacturing represents an emerging and promising solution for the construction sector. Three-dimensional printing allows the creation of custom geometries, reduces material waste, and automates the construction process. This work aims to compare the thermal performance of a PLA (polylactic acid) 3D-printed block with an internal honeycomb structure whose air cavities are filled with natural and recyclable waste-insulating materials. The selected air cavity filling materials are (i) wood sawdust, (ii) sheep’s wool, and (iii) hemp. The thermal behavior of the...
Comparative Examples of the Evolution of Thermal Cameras in Artwork Diagnostics: An Experimental Perspective
Lecture notes in mechanical engineering, Oct 12, 2022
Building energy performance analysis at urban scale: A supporting tool for energy strategies and urban building energy rating identification
Sustainable Cities and Society, 2021
Abstract The energy consumption of the building sector has complex and interrelated characteristi... more Abstract The energy consumption of the building sector has complex and interrelated characteristics. The development of modeling techniques capable of evaluating the impacts of energy-efficient technologies requires great effort owing to the variety of building sizes and geometries, wide range of thermal properties of building envelopes, variable occupant behavior, and lack of measured consumption data. However, energy policies require thorough knowledge of the energy performance of a building stock to be truly effective. In this paper, an urban-scale building energy modeling tool based on an engineering bottom-up approach is presented. The employed methodology makes it possible to assess the energy performance of a building stock, define energy efficiency measures, and evaluate their effects automatically using a geographic information system. Moreover, the modeling tool introduces an innovative urban building energy rating similar to the energy rating of individual buildings. The proposed energy modeling tool is then applied to a real case consisting of three villages in central Italy with 769 residential buildings.
Tecnica Italiana-Italian Journal of Engineering Science, 2021
The thermal characterization of building envelope materials is a crucial phase in understanding t... more The thermal characterization of building envelope materials is a crucial phase in understanding the building energy performance, and it is commonly evaluated through the thermal transmittance, often synthetically indicated as U-value. There are several ways to experimentally assess the U-value of insulating materials and multi-layers systems, usually defined by means of experimental in-situ heat flux measurements, where, however, a considerable variation of the boundary conditions may occur, making the measurement difficult. In this work, the experimental thermal characterization of different insulating materials applied to an X-lam wall is presented. The analysis is carried out using a Guarded Hot Box, which allowed to reproduce real, repeatable, and controlled operating conditions. Two different insulating materials were selected: expanded polystyrene (EPS) with graphite and hemp. The experimental tests were carried out by imposing a temperature difference reproducing the common o...
Spice Model of Photovoltaic Panel for Electronic System Design
Lecture Notes in Electrical Engineering, 2020
The aim of this work is to propose a Spice model of photovoltaic panel for electronic system desi... more The aim of this work is to propose a Spice model of photovoltaic panel for electronic system design. The model is based on Rp-model of PV cell and implements the open-circuit voltage and short-circuit current variations from temperature and solar irradiation. The model was implemented on the LTSpice software characterized by comparing the System Advisor Model (SAM) software and MATLAB models with a commercial panel. The results of IV and PV curves are here reported.
IR thermography as a preliminary tool in acoustical inspection of ancient historical structures
2017 IEEE International Conference on Environment and Electrical Engineering and 2017 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe), 2017
Infrared thermography is a well-known non-destructive diagnostic tool. It has many applications i... more Infrared thermography is a well-known non-destructive diagnostic tool. It has many applications in science and engineering. In this paper, IR thermography is proposed as a tool for helping acoustical inspection of historical buildings, because of its ability in detecting lack of homogeneity in walls. The main features of this idea are discussed and some results are provided.
Scientific Reports, 2021
Dual mode imaging in the mid infrared band, a joint use of thermography and quasi-thermal reflect... more Dual mode imaging in the mid infrared band, a joint use of thermography and quasi-thermal reflectography, was recently proposed as a full field diagnostic tool in cultural heritage. Here we discuss for the first time, to the best of our knowledge, a detailed application of such non destructive technique to the diagnostics of frescoes, with an emphasis on the location of detachments. We also investigate the use of a thermographic method based on TSR (thermal signal reconstruction), in a long pulse stimulus scheme, as well as the spatial registration of thermal images after post-processing analysis to their visible counterpart, so as to obtain a fine resolution diagnostic map. As an exemplar case study, we report about the application of dual mode imaging with a 500 $${\upmu }\hbox {m}$$ μ m pixel size at object plane on the “Monocromo”, a fresco by Leonardo da Vinci located in the Sforza Castle (Milan, Italy). Our technique was used to guide the conservators during the restoration wo...
E3S Web of Conferences, 2021
In this study, convective heat transfer phenomena were investigated by means of a Guarded Hot Box... more In this study, convective heat transfer phenomena were investigated by means of a Guarded Hot Box (GHB) apparatus. An experimental setup characterized by air and surface temperature probes, and a hot-wire anemometer was used. Five small fans were installed in the metering chamber to generate a forced air flow characterized by different velocity values. So, the GHB was used for investigating the influence of different air speed values on internal convective coefficients. Considering horizontal heat fluxes, an internal convective coefficient values of 2.5 W/m2K is reported in the Standard ISO 6946. However, no exhaustive description about this value is provided. The aim of this work is to experimentally determine the internal thermal surface resistance, quantifying how the convective heat transfer coefficient varies as air velocity changes.
E3S Web of Conferences, 2021
In this paper, the main results obtained for the identification of energy efficiency measures (EE... more In this paper, the main results obtained for the identification of energy efficiency measures (EEMs) in archetype public buildings selected by the Abruzzo Region within the European Project SHERPA (SHared knowledge for Energy Renovation in buildings by Public Administration), a three-year project involving 12 partners from the Mediterranean area, are presented.The analysis presented in this work was carried out on 12 public buildings, with different intended use, located in the four provinces of the Abruzzo Region characterized by different climate conditions. For each building, a complex work of documents acquisition has been carried out together with the regional coordinators of the Project. These documents have allowed the energy assessment of the selected buildings in their current condition. The second phase of the study has instead focused on the effects resulting from the application of EEMs on both passive and active components, in terms of energy savings and greenhouse gas ...
IOP Conference Series: Materials Science and Engineering, 2019
This work presents the energy performance analysis of an autarkic residential building, located i... more This work presents the energy performance analysis of an autarkic residential building, located in the suburb of L’Aquila, in central Italy. The analysis is performed via a calibrated dynamic thermal model, carried out with EnergyPlusTM engine coupled with DesignBuilder. The aim of this study is the further understanding of the optimization margins of the energy self-sufficient building by considering different Energy Efficiency Measures and the effects obtainable in different climatic conditions. Four Italian cities and three European capitals are considered, in addition to different scenarios, characterized by various technological plants. In fact, a significant difference between the high efficiency of the envelope, and the poor performance of the heating system was observed. The results highlighted the remarkable energy performance optimization of the analyzed building, although the effects of the Energy Efficiency Measures showed notable differences between colder and warmer cl...
Energy Procedia, 2017
District heating networks are commonly addressed in the literature as one of the most effective s... more District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing the greenhouse gas emissions from the building sector. These systems require high investments which are returned through the heat sales. Due to the changed climate conditions and building renovation policies, heat demand in the future could decrease, prolonging the investment return period. The main scope of this paper is to assess the feasibility of using the heat demand-outdoor temperature function for heat demand forecast. The district of Alvalade, located in Lisbon (Portugal), was used as a case study. The district is consisted of 665 buildings that vary in both construction period and typology. Three weather scenarios (low, medium, high) and three district renovation scenarios were developed (shallow, intermediate, deep). To estimate the error, obtained heat demand values were compared with results from a dynamic heat demand model, previously developed and validated by the authors. The results showed that when only weather change is considered, the margin of error could be acceptable for some applications (the error in annual demand was lower than 20% for all weather scenarios considered). However, after introducing renovation scenarios, the error value increased up to 59.5% (depending on the weather and renovation scenarios combination considered). The value of slope coefficient increased on average within the range of 3.8% up to 8% per decade, that corresponds to the decrease in the number of heating hours of 22-139h during the heating season (depending on the combination of weather and renovation scenarios considered). On the other hand, function intercept increased for 7.8-12.7% per decade (depending on the coupled scenarios). The values suggested could be used to modify the function parameters for the scenarios considered, and improve the accuracy of heat demand estimations.
Applied Energy, 2018
An energy self-sufficient house with high performance materials is studied. • The building perfor... more An energy self-sufficient house with high performance materials is studied. • The building performance is evaluated through numerical and experimental analysis. • Results show that even a self-sufficient house has optimization margins. • A multi-scenario analysis is proposed to optimize the energy performance. • Uncertainty and techno-economic analyses are also briefly discussed.
Journal of Building Engineering, 2018
The addition of insulating layers on vertical walls of buildings is a common practice for providi... more The addition of insulating layers on vertical walls of buildings is a common practice for providing a higher thermal insulation of the envelope. Workmanship defects, however, might influence the effectiveness of such insulation strategy. Damaged materials, incorrect installation, use of aged or weathered materials might alter the capability of reducing heat transfer through the envelope, whether vertical or sloped. In this work, drawbacks caused by the wrong installation of insulating material and by damaged material are assessed. A specimen wall was investigated by experimental and numerical approaches, the latter carried out by using COMSOL Multiphysics®. Results are compared and discussed.
Construction and Building Materials, 2017
h i g h l i g h t s Endothermic events were discovered both in pure and modified HDPE samples. A ... more h i g h l i g h t s Endothermic events were discovered both in pure and modified HDPE samples. A pseudo-static matrix reconstruction algorithm applied to IRT data was used. Thermocouples monitored the temperature variation in time during the tensile tests. The UV optical transparency in the modified HDPE increased after the tensile test. Numerical and experimental temperature variations follow similar trends in time.
Energy Conversion and Management, 2016
Because of the growing need for efficient energy production systems, energy policies promoted in ... more Because of the growing need for efficient energy production systems, energy policies promoted in recent years have also involved complex structures, like airports. This paper proposes the implementation of an energy management system for a very energy-consuming structure, composed of different power plants and many energy consumers: the Leonardo da Vinci International Airport of Rome. In this study, the examination of historical data related to airport electric power, thermal energy and fuel consumption is discussed, starting with the analysis of the production energy plants, mainly based on a combined heat and power system. Furthermore, pioneering solutions are proposed, not only to cover airport energy requirements, but also to test the safety and reliability of innovative load management systems. For this reason, the choice of the Leonardo da Vinci management company, oriented to install a smart storage in order to manage the bidirectional energy flows by consumers and producers, is justified. Such innovative energy procurement systems are examined, with the goal of achieving greater penetration of renewable sources: mini and micro wind power plants and high concentrator photovoltaic plants.
Optics for Arts, Architecture, and Archaeology VIII, 2021
Infrared methods are of great importance in nondestructive testing of artworks, allowing a remote... more Infrared methods are of great importance in nondestructive testing of artworks, allowing a remote and wide-field imaging of interesting hidden features. Here we discuss a workflow based on thermal imaging in the mid infrared 3-5 micron range for the evaluation of subsurface defects in frescoes. Particular attention is payed to obtaining a high resolution (submillimetric) localization of the defects. The transfer of diagnostics techniques into real world applications, is discussed through the proof of concept of the proposed workflow on frescoes at the Sforza Castle (Milan, Italy).
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Papers by dario ambrosini