1,720,995 research outputs found
Indice di severità climatica: classificazione dei comuni italiani ai fini della climatizzazione estiva degli edifici
Full text linkL'applicazione del Dlgs.192/05, prevede che ai fini della certificazione energetica in edilizia, sia valutato il fabbisogno di energia primaria di un edificio, e successivamente, sia assegnata ad esso, in funzione di tale parametro, una classe di efficienza energetica. Al momento, in Italia, sono stati fissati i limiti al fabbisogno solo per quanto riguarda la climatizzazione invernale. Il territorio nazionale è stato suddiviso, infatti, in zone climatiche invernali in conformità a un indice climatico, definito dai gradi-giorno invernali, e sono stati individuati i valori limite del fabbisogno energetico su tale base. La diffusione dei sistemi di condizionamento estivi, con il conseguente aumento dei consumi energetici, rende necessario procedere, anche in tal caso, alla definizione di zone climatiche estive contraddistinte da un indice di severità climatica estivo. La definizione di questo indice estivo presenta maggiori difficoltà rispetto al corrispondente indice invernale giacché le variabili climatiche di cui tenere conto sono più numerose e più complesse da valutare. Nei precedenti lavori è stata proposta una prima applicazione di tale indice ed è stata verificata la validità del modello matematico utilizzato, prendendo in esame, per il calcolo del fabbisogno energetico per il raffrescamento estivo al variare delle caratteristiche climatiche (temperatura, radiazione solare e umidità), prima un edificio residenziale, e in seguito, un edificio del terziario ad uso ufficio situati in venti località di riferimento; ne è conseguita la assegnazione di 101 capoluoghi di provincia a sette zone climatiche estive (da A a G) di indice di severità estivo e, quindi, di fabbisogno energetico crescente. Nel presente lavoro sono descritte le modalità di calcolo seguite per l'estensione della valutazione dell'Indice di Severità a tutti i comuni italiani: partendo dai dati climatici riportati nella UNI 10349/94 per 101 province italiane, e seguendo, di massima e là dove possibile, i criteri di interpolazione dei dati esposti nella norma, sono state valutate per le varie località in esame, le tre grandezze climatiche fondamentali: Temperatura, Irradiazione solare e Umidità specifica. Successivamente è stato possibile calcolare l'Indice di Severità Climatica e assegnare, in funzione di esso, una classe climatica agli 8094 comuni italiani.The application in Italy of the European Directive 2002/91/CE, about the energy performance of buildings, through the Dlgs.192/05 and Dlgs.311/06, provide for the energy certification in building. The certification means the calculation of a parameter, the building specific requirement of primary energy, and the successive allocation of the building, as function of the value of such parameter, to a certain energy efficiency class. At the moment just limits for heating energy need in winter, have been fixed. The national territory has been subdivided, in fact, in winter climatic zones in compliance with an index of climatic severity (heating degree-day) and limit values for the energy requirements has been set. The spread of the summer air conditioning systems, with the consequent increase of the energy consumptions, renders necessary to proceed, also in such case, to the definition of summer climatic zones by a summer
index of climatic severity. The summer index definition involves greater difficulties regarding the correspondent winter index since climatic variables, in this case, are more numerous and complex to estimate. In a previous reports a first application of such index has been proposed, and has been tested the effectiveness of mathematical model, taking into account a residential building and an office building, to evaluate the
cooling energy need: in this way, have been classified the Italian provincial capitals in summer climatic zone. This work describes the calculation method to extend the Severity Climatic Index at all Italian towns: starting from climate data given on the UNI 10349, and following the interpolation methods described in the standard, have been evaluated the main climate parameters for each town: air temperature, specific humidity and solar radiation. Subsequently has been calculated the Severity Climatic Index and a climate class has been assigned to each Italian town
Downscaling of Hourly Climate Data for the Assessment of Building Energy Performance
Full text linkIn Italy, the calculation of the energy needs of buildings has been mainly based on quasi-steady state calculation procedures. Nowadays, the increasing interest in more detailed energy analysis for high-efficiency buildings requires more accurate calculation methods. In this work, starting from the hourly data of UNI 10349, the downscaling of a typical meteorological year was carried out by applying different mathematical and physical models for the main climate variables considered in the energy balance of a building to be used in dynamic simulation tools. All results were validated with one-minute measurements observed at the ENEA Research Centre in Rome, Italy. The results showed an MBE% of 0.008% and RMSE% of 0.114% using the interpolation spline method for the temperature, while, for the global horizontal irradiance, applying the novel sinusoidal–physical interpolation method showed an MBE% of −0.4% and an RMSE% of 31.8% for the 1 min observation data. In this paper, an easily implemented novel model for downscaling solar irradiance for all sky conditions that takes into account the physical aspects of atmospheric phenomena is presented
A new simplified dynamic algorithm for energy estimation in buildings: Description and validation
No full textAmong other energy savings policies, European Directive 2018/884 promotes the adoption of building energy audits. In this perspective, the development of accurate, but simplified dynamic energy simulation tools is a fundamental step to reduce the costs of energy audits and consequently increase their diffusion, especially at the professional level. This paper presents SEAS Light, a simplified dynamic tool that estimates building heating and cooling energy demands. 75 test cases associated to typical Italian climates and building structures have been performed. SEAS Light results are compared with the ones obtained through the full dynamic energy software TRNSYS 17. The validation procedure shows that the proposed routine can evaluate both seasonal heating and cooling energy demands with a good accuracy, using three tuning coefficients presented in the manuscript
Development of daylight availability maps in Italy: Methodology and validation
No full textThis paper describes a study aimed at providing outdoor illuminance data in Italy, to be used to evaluate daylight potential contribution in the energy performance of buildings. Starting from solar radiation data, a luminous efficacy model was implemented to derive outdoor illuminance for Italian territory. The results obtained were compared with ground measurements, carried out in three different Italian sites (Milan, Rome and Lampedusa island), and the accuracy of model, has been improved introducing specific metrics for Italian context. Typical Meteorological Years (TMYs) of global and diffused components of daylight illuminance, were built for 243 locations, considering different time profiles. Since the definition of the spatial and temporal trend of environmental variables or metrics requires the application of appropriate interpolation procedure, geostatistic methods (kriging), was used to develop Italian daylight maps. The daylight availability maps will be included in the Italian database of solar radiation (www.solaritaly.enea.it) providing an useful tool for lighting energy performances in buildings applications
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