1,721,015 research outputs found
Evaluation of energy, thermal, and daylighting performance of solar control films for a case study in moderate climate
No full textSolar control films could be a suitable way to reduce cooling energy consumptions and to reduce discomfort conditions in existing glazed buildings, but their performance is often evaluated by numerical analysis only. In this paper, an integrated thermal-energy and lighting characterization of solar control films performance was carried out by full-scale experimental setup and numerical analysis: two similar offices, with and without solar control films, in a multifunctional building in moderate climate were investigated. Solar control films strongly reduced the incoming solar radiation (about 60%), not depending on the external solar radiation. During springtime, window films allowed a reduction of about 2-3 C of the indoor air temperature, during sunny days; they influenced also the globe thermometer temperature: with window coatings, it is almost equal to air temperature, whereas with conventional windows, it is about 2 C higher, especially in the afternoon, due to the contribution of glass surface temperature (which is 10 C higher). Furthermore, the contribution of artificial light increases, especially on cloudy days, because the daily average illuminance level was lowered by about 59%. Finally, preliminary simulations showed that the cooling energy demand decreases of about 29% thanks to solar control films, but at the same time the energy demand for heating increases of about 15%
Innovative mineral fiber insulation panels for buildings: Thermal and acoustic characterization
No full textThermal insulation of building envelope plays a key-role in energy saving: a growing interest is focused on new materials, such as the recycled and sustainable ones. Innovative mineral fiber insulating panels were developed and investigated as a strategy for building refurbishment. The thermal and acoustic properties were investigated in order to compare them to conventional solutions. The thermal conductivity was evaluated by means of a Heat Flow meter apparatus: it is in the 0.0310.034 W/(m K) range, depending on the density. The acoustic absorption coefficient and the Transmission Loss values measured by means of Kundt’s Tube showed a very good acoustic behavior, when compared to conventional solutions with similar chemical composition, but worse mechanical resistance, such as rock wool panels. The low value of thermal conductivity (0.0312 W/(m K) for a density of 165 kg/m3), together with other characteristics such as acoustic insulation improvement, sustainability (very low presence of additives, such as resin), mechanical resistance, high resistance to fire, and finally easy application in buildings with very low thicknesses (927 mm) suggest this solution as a very useful one for building refurbishment, especially for historical buildings
The influence of glazing systems on energy performance of non-residential buildings
No full textGlass façades have an important role in buildings both for daylighting and thermal comfort. Many studies
showed that health, comfort and productivity are improved due to access to natural light. Moreover the
thermal and solar transmittance, the size and the orientation of the windows are very important in the energy
use in buildings. The aim of the paper is to evaluate the influence of glass components in energy saving for
non-residential buildings. A multifunctional building was investigated and a dynamic thermal model was
implemented by means of EnergyPlus software. The energy demand was estimated in different climatic
conditions and for different building orientations both for heating and cooling. The weather data of five Italian
cities (Perugia, Rome, Palermo, Milan, Bolzano) were considered. In order to evaluate the impact of
windows, different kind of glazings were selected: double-glazing with low-e coating and sunlight control
double glass windows. Moreover, innovative glazing systems with silica aerogel (pane and granular) in
interspace were investigated as a solution for energy saving in buildings. Finally, also the effects of blind
systems on the façades were evaluated.
Results showed that not only the thermal transmittance but also the solar transmittance of glazing has a
large effect on thermal comfort and energy demand, depending on the chosen locality. The dynamic building
models implemented in EnergyPlus software are very powerful tools and could allow to select for each
scenario appropriate fenestration types, thanks to an accurate balance between energy consumption,
thermal comfort and daylighting needs
Evolutive Housing System: refurbishment with new technologies and unsteady simulations of energy performance
No full texttThe aim of the present paper is to evaluate the energy performance in unsteady-state conditions ofan Evolutive House. The original design was presented by two important architects, Renzo Piano andPeter Rice, in 1978. The house has two large glass walls in the east and west fac ̧ ades. Experimentalinvestigation and numerical analysis were carried out in a prototype of the house realized in Perugia. Theair temperature, the surface temperature of floors, the global solar radiation, the relative humidity weremeasured. Simulations were performed using both Energy Plus and TRNSYS software. Simulation modelswere tested and validated with experimental data considering a new weather database compiled forPerugia. The analysis compares different scenarios in terms of energy demand, such as the substitutionof the glazing and the use of innovative packaged solutions. Innovative glazing systems filled with silicaaerogel were investigated as a solution for energy saving in buildings. Results show that an importantenergy saving was obtained for all the proposed glazings (about 60–70%). The simulation codes’ resultsare in good agreement, but some differences are due to the different approach in the evaluation of thesolar irradiance on tilted surfaces and to the transient heat conduction model
Natural lighting in glazed buildings: energy balance
No full textDue to energy consumption increasing and building internal comfort requirements, the application of design strategies is mandatory in order to improve lighting efficiency and to use daylighting techniques. For new and existing buildings, the challenge becomes the achievement of both maximum lighting efficacy and maximum energy-efficiency, according to law’s specifications. In recent years, daylighting algorithms incorporated in building energy simulation programs have become increasingly sophisticated in their abilities to predict the illuminance, light power reductions, and associated thermal load interactions.
The aim of this paper is to analyse simulated light levels of a non-residential building. An existing multifunctional building was investigated and in particular the offices placed at the second floor (with a large glazing system in the south façade); a model was implemented in DIALux. It was calibrated thanks to in-situ measurements: the daylight illuminance was monitored by illuminance meters in a typical office.
After the model validation, illuminance was simulated with different glazings: standard double-glazing system, systems with granular silica aerogel in interspace, double-glazing with sunlight control films and the influence of blind systems on the glazing facade was also evaluated. Furthermore different lighting plants were implemented, in order to compare a traditional solution and a LED lighting system, in terms of illuminance distribution and operating cost.
Results showed that the best solution in terms of natural lighting is the standard glazing with blind systems: the shading device allows the entry of the natural light for many hours during the day, avoiding also glare problems. Considering the solar control films and the aerogel system, the turn-on periods of the lighting system during a day is too long. Concerning the lighting systems, LED lamps have a lower rated power and therefore a saving in terms of energy absorption. Despite the higher luminous flux turns out to be that of compact fluorescent lamps, LED lamps have more luminous efficiency and a longer service life
The Influence of Solar Control Films on Energy and Daylighting Performance by Means of Experimental Data and Preliminary Unsteady Simulations
No full textAbstractSolar control films were investigated as a strategy to improve thermal comfort, lighting conditions, and energy performance in non-residential buildings. The case study follows two adjacent similar offices with large window in the south-west façade of a building in Perugia, investigated by numerical and experimental approaches. The solar control films could strongly reduce the window heat gain (40-60%) and the indoor air temperature (1-1.5°C), whereas the daily average illuminance level was lowered by about 50-60%. Finally the yearly cooling energy demand decreases of about 25% (only South- West façade) and 39% (all the façades), whereas the heating energy demand increases of about 10-15% thanks to solar control films
Development of innovative aerogel based plasters: thermal and acoustic performance evaluation
No full textMonitoring and Energy Simulation Analysis of a Mechanical Workshop with Photovoltaic System and Electric Mobility Infrastructures Integration
No full textThe industrial sector is a significant part of the global economy, responsible for most energy consumption and worldwide emissions. In particular, mechanical workshops are very widespread in Italy; they are experts in the production, machining and marketing of precision engineering products. In this paper, an Italian mechanical workshop involved in mechanical production, has been studied. The electrical loads were monitored and analyzed over a period of four years and an energy model was developed to determine the electrical consumption of heat pumps used for the air conditioning of the building. The annual electricity production of a PV system installed on the roof was also analyzed. The annual trends were compared in order to assess the benefits achievable through the installation of a storage system. In the overall scenario of the company's electrification, an optimization model was also developed to determine the benefits to be gained from the implementation of electric mobility infrastructures: the optimal size of batteries and the number of EVs charging stations were determined based on the economic analysis
Isolamento acustico di elementi edilizi prefabbricati: stima teorica e analisi sperimentale
No full textThermal Conductivity Measurements By Means of a New ‘Small Hot-Box’ Apparatus: Manufacturing, Calibration and Preliminary Experimental Tests on Different Materials
No full textThe evaluation of the thermal performance building components requires a high level of accuracy. Windows, doors and thermal bridges are not homogeneous, and their thermal transmittance can be evaluated by means of Hot-Box, used for full-scale elements. For homogeneous materials and one-dimensional heat flux, the thermal conductivity can be easily measured through other experimental apparatuses, such as the guarded hot plate and the heat flow meters. This study presents a new experimental apparatus named Small Hot-Box, built at the University of Perugia. No European standards are available for this innovative facility, but it takes into account some prescriptions of EN ISO 8990 and EN ISO 12567; it was built for the evaluation of the thermal properties of small specimens. The apparatus was designed, built, and calibrated by means of preliminary measurements. It is composed of a hot and a cold side, and the external walls are made of thick insulation. The thermal conductivity can be calculated by two different methodologies: the Hot-Box and the thermal flux meter method. Preliminary calibrations were carried out and different materials with known thermal transmittance were tested. The aim is the development of a new experimental apparatus; guidance documents could be defined for the measurements methodology requirements
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