Thermal infrared imaging is a valuable tool to perform non-destructive qualitative tests and to investigate buildings envelope thermal-energy behavior. The assessment of envelope thermal insulation, ventilation, air leakages, and HVAC performance can be implemented through the analysis of each thermogram corresponding to an object surface temperature. Thermography also allows the identification of thermal bridges in buildings’ envelope that, together with windows and doors, constitute one of the weakest component increasing thermal losses. A quantitative methodology was proposed in previous researches by the authors in order to evaluate the effect of such weak point on the energy balance of the whole building. In the present work, in-field experimental measurements were carried out with the purpose of evaluating the energy losses through the envelope of a test room experimental field. In-situ thermal transmittance of walls, ceiling and roof were continuously monitored and each element was characterized by its own thermal insulation capability. Infrared thermography and the proposed quantitative methodology were applied to assess the energy losses due to thermal bridges. The main results show that the procedure confirms to be a reliable tool to quantify the incidence of thermal bridges in the envelope thermal losses.
The evaluation of the overall performance of a green building is complex, since many construction, energy and environmental aspects have to be considered. The Umbria Region in Italy, through various public tenders, recently funded several residential buildings, innovative in terms of construction quality, green technologies and sustainable solutions, such as natural building materials, integrated sunspaces, PV (photovoltaic) modules and solar collectors, geothermal heat pumps, that had to be adopted to obtain the public contribution. The University of Perugia carried out an extended monitoring of these buildings, in order to verify the actual achievement of design objectives, to certify the real savings in terms of energy and environmental loads and to assess the indoor comfort conditions for occupants. In situ thermal, acoustical and lighting measurements were carried out for more than one year. Energy simulations were performed by means of codes which implement the algorithms required by the Italian Law. Moreover, a comparison between real consumptions and simulated energy requirements was carried out. Finally, the buildings were characterized from the environmental sustainability point of view, using the method adopted by the Umbria Region. This assessment was borrowed from ITACA (Institute for Innovation and Transparency in Government Procurement and Environmental Compatibility) procedure [an Italian procedure similar to Leadership in Energy and Environmental Design (LEED)] and consists of 20 worksheets, one for each different performance indicator, at the aim of carefully describing the environmental quality of the building.
This paper analyzes the impact of a change in the thermal insulating material on both the energy and environmental performance of a building, evaluated through two different green building assessment methods: Leadership in Energy and Environmental Design (LEED) and Istituto per l’innovazione e Trasparenza degli Appalti e la Compatibilità Ambientale (ITACA). LEED is one of the most qualified rating systems at an international level; it assesses building sustainability thanks to a point-based system where credits are divided into six different categories. One of these is fully related to building materials. The ITACA procedure derives from the international evaluation system Sustainable Building Tool (SBTool), modified according to the Italian context. In the region of Umbria, ITACA certification is composed of 20 technical sheets, which are classified into five macro-areas. The analysis was developed on a residential building located in the central Italy. It was built taking into account the principles of sustainability as far as both structural and technical solutions are concerned. In order to evaluate the influence of thermal insulating material, different configurations of the envelope were considered, replacing the original material (glass wool) with a synthetic one (expanded polystyrene, EPS) and two natural materials (wood fiber and kenaf). The study aims to highlight how the materials characteristics can affect building energy and environmental performance and to point out the different approaches of the analyzed protocols.
The basic idea of the EU LIFE+ 2011 project MuSAE (“Municipalities Subsidiarity for Actions on Energy”, code LIFE11 ENV/IT/000016) consists of transferring the skills and experience related to energy planning, acquired by the leading beneficiary, the Municipality of Perugia, to three small- or medium-sized Umbrian Municipalities (Marsciano, Umbertide and Lisciano Niccone). This transfer is aimed, among other objectives, at the drafting of the Municipal Energy and Environmental Plan (MEEP) and the opening of an energy information office in each partner Municipality, in cooperation with CIRIAF and Umbria Region. The present paper provides a summary of MuSAE activities, analyzing the procedures and modalities of implementation of the various phases of the MEEPs, on the basis of the experience gained over the years through the collaboration with the Municipality of Perugia and adapted to smaller territories such as those represented by the other partner Municipalities. A summary of the dissemination activities and pilot projects is also presented, testifying the first concrete results of the planning activity developed by each administration within the project.
The paper presents a simplified mathematical model to describe the transient heat transfer of a radiant floor heating system. A purpose-built test room has been realized to investigate the actual thermal response of a concrete radiant floor in unsteady-state conditions. Beyond the temperature sensors needed for the standard thermal analysis of the heat transfer inside the chamber, the floor temperature was retrieved by means of an infrared thermography camera, in order to validate more precisely the proposed analytical model. The infrared thermography analysis gives interesting information on the floor temperature distribution during the transient, highlighting the pipes’ layout and, if present, inhomogeneous floor zones. The thermal images have been elaborated in order to set and tune the colour map. A portion of the image has been defined for measuring the surface floor temperatures with a previous evaluation of the parameters dealing with the thermographic technique, in order to perform the quantitative survey. The comparison results show that the calculated air and floor temperatures substantially agree with the temperatures measured by infrared thermography and thermocouples, provided that the boundary conditions obtained by the field measurements are strictly reproduced in the lumped capacitance mathematical model. The difference between the two approaches results in values lower than 4 °C during the entire monitoring period: a satisfactory outcome, considering the approximations of the analytical method. The proposed model and its infrared thermography measurements validation represent a useful tool to understand at first sight the floor radiant panels behaviour in the start-up and switch off period, at the aim of gather useful information for the difficult task of their regulation.
In this paper, we develop a procedure for the detection of the contours of thermal bridges from thermographic images, in order to study the energetic performance of buildings. Two main steps of the above method are: the enhancement of the thermographic images by an optimized version of the mathematical algorithm for digital image processing based on the theory of sampling Kantorovich operators, and the application of a suitable thresholding based on the analysis of the histogram of the enhanced thermographic images. Finally, an accuracy improvement of the parameter that defines the thermal bridge is obtained.