Simulation of the Thermal Behaviour of Buildings Equipped with Low-Emissivity Glazed Components. A Performance Analysis

In this paper, the authors want to highlight the different kinds of thermal behavior under dynamic conditions of buildings based on the use of two different types of glass for the windowed components: in the first type under consideration a double-standard 4-12-4 glass is adopted, while in the second a low emissivity glass of equal thickness is used with the presence of a coating on the inner face of the window.The analysis focuses on the determination of the indices of thermal comfort in the environment, both in free and in forced evolution, and consumptions of the HVAC plant when the system is functioning. For the evaluation of the above parameters, the analysis is initiated by determining the time profile of the internal temperature, of the internal surface temperature of the window and the time profile of the mean radiant temperature after properly defining the computational grid for the software. The simulations to evaluate the energetic advantage of the types of windows analysed, were carried out for two different case studies and in three different climatic zones through the use of Ecotect software.After determining the temperature profiles mentioned above and calculating the indices for the thermal comfort PMV (Predicted Mean Vote) and PPD (Predicted Percentage of Dissatisfied) in accordance with the UNI EN ISO 7730:2006, the annual energy required for the air conditioning system and for the maintenance of the temperature set point within the environment were evaluated. Subsequently, the energy certification for the second case study was performed on the basis of the indications of the technical specifications UNI TS 11300-1:2008 and 11300-2:2008, with the objective of determining what benefits are obtained from the point of view of the energy class, simply by changing the properties of the windows.