Search

Computational Fluid Dynamics (CFD) simulations are sensitive to input uncertainties and human errors. Using real-world data as an input for CFD simulations is not rare for building physics simulations and it is still an open topic. In most cases, computer simulations using CFD are for design purposes and they aim to represent the situations occur in the real-world. The real-world parameters are commonly set based on experimental measurements. However, it is known that experimental measurements are affected by uncertainties; hence the experimental values have to be processed to calibrate numerical simulations. This paper investigates the CFD simulation calibration through experimental measurements. In particular, a statistical approach is employed to study the experimental data of inlet-outlet velocities for ten non successive days in a test-room with the purpose of assuming a surrogate day input that is the most significant of the dataset. Moreover, five different input methods on the boundary conditions of inlet velocity obtained from the experimental measurements are implemented and the accuracy of the predicted results through CFD simulations is presented. For the first input, the actual measurements of one particular day were chosen among the ten available days. For the other four, the numerical input relating to each second of the synthetic day was constructed by means of a statistical assessment of the actual measures obtained at each corresponding second of the ten actual days. The Hermite polynomial chaos expansion was selected for the last approach. Results have shown a significant variability of airflow for both experimentally measured input and output signals. By using the experimental signal expansion through Hermite polynomials the experimental and numerical values give satisfactory results. [ABSTRACT FROM AUTHOR]

In the perspective of reducing land occupation of built environments, the most efficient strategy is to increase the reuse of obsolete or abandoned constructions instead of designing new buildings. This is particularly true regarding public buildings, usually characterized by considerable dimensions. The paper is focused on this issue, particularly on its energy implications. It analyzes the headquarters of the 'G. D'Annunzio' University in Pescara, Italy, initially designed for commercial use and later converted to a university building during its construction. The authors first carried out a numerical analysis of the building energy performance in its current state and then they proposed some improvement interventions evaluating their incidence on the annual energy balance of the building, showing how the most commonly used energy saving strategies do not give the best results in any case, being greatly influenced by the climatic zone in which the building is located. Starting from these considerations, the authors carried out the analysis by considering three different Italian climatic conditions so as to determine their influence on the building energy performance and to define the best strategy for energy requalification in each climatic zone. [ABSTRACT FROM AUTHOR]

The paper investigates the shape dependence of the acoustic performances of space with different plans covered by a hyperbolic paraboloid cables net and membrane roof. In addition, the paper study the differences of acoustic performances between four different configurations: sport arena and empty, partially occupied and full concert hall. The aim is to compare the shape dependence of the acoustic response for each configuration. The study is focused on different geometries: four different plan shapes (i.e., square, circular, rectangular and elliptical) and two different curvatures. The differences of acoustic efficiency are compared using some representative parameters like the reverberation time, ( $$T_{30}$$ ), the clarity ( $$C_{80}$$ ), the definition ( $$D_{50}$$ ) and the initial time delay gap. In addition, the paper compares the acoustic response for all concert hall configurations and all geometries with permanent and temporary improvements. [ABSTRACT FROM AUTHOR]

Textile roofs are particularly suited for covering large open spaces. They are used to make buildings that are able to dynamically change their functions. Their strengths are their great lightness and thinness. These characteristics are optimal for their load bearing function, as a roof covering, but they are not so good for the acoustic performance of the structure. This aspect is important because it makes it difficult to transform a sports arena, for example, into a music hall or auditorium. The possibility having these transformations is economically important for this kind of building. This paper is focused on the acoustic performance of a building covered with a flexible roof made of a cable net and membrane. In this specific case, the roof has a hyperbolic paraboloid geometry, and the building footprint is elliptical. The interaction between shape and acoustic performance is investigated. An acoustic improvement is proposed for the double functional aim of satisfying both speech and music. This improvement is obtained using acoustic absorbing and diffusing panels. [ABSTRACT FROM AUTHOR]

The use of scale models is widely adopted as an efficacy method for determining the daylight assessment of interior areas of buildings. Scale models can be tested under real sky or sky simulators. In both cases, it is commonly accepted among the researchers that the use of scale models leads to an overestimation of experimental data with respect to real scale test rooms. Starting from this assumption, the authors have carried out an experimental analysis under real sky on a reduced scale model of a test room equipped with a window and on two scale models of a room equipped with a double light pipe in order to define the influence of the scale factor on experimental data both with traditional and innovative daylight sources. The analysis leads in particular to identify the influence of direct solar radiations on the results. Although the authors agree with the majority of researchers and confirm the common opinion that daylight performances are generally overestimated in scale model analysis, this study evidences that the presence of intense direct radiations can produce exceptions and the opposite case can be experienced. [ABSTRACT FROM AUTHOR]

In the original article, the reference Rizzo and Ricciardelli (2017) was incorrectly published. The invalid reference and the corrected reference are given. [ABSTRACT FROM AUTHOR]

An innovative arrangement able to transmit daylight into hypogeal rooms and, simultaneously light the passage spaces, is presented. It is named the 'Double Light Pipe'. It consists of two coaxial tubes: the inner cylinder is a traditional light pipe, which transmits light from a clear collector, placed on the roof top of the building, downward to a diffuser inside the underground areas, while the outer one allows light to enter into the passage spaces. A numerical analysis has been carried out using ECOTECT and RADIANCE software and the results are compared with a reduced scale experimental analysis. [ABSTRACT FROM AUTHOR]