Search results for "Solar radiation"

An Overview on Solar Shading Systems for Buildings

2014

Abstract In recent years, different types of solar shading devices have been proposed, depending on building orientation, location, window characteristics, etc. They can contribute to improve or worsen building thermal and lighting performances both from an energy and comfort point of view. The present paper reports a critical analysis of some studies that investigate shading devices’ effects on building thermal and/or lighting performances. This article points out the difficulty in comparing the different results given the lack of uniformity between the studies, since they analysed buildings with different characteristics, locations and using various indices. Therefore a protocol to carry …

Generation of a Test Reference Year (TRY): an application to the town of Palermo

2012

The improvement of the energy efficiency of buildings calls for the availability of tools for evaluating and simulating the thermal behaviour of buildings, needing as input climatic databases. These databases contain a very large amount of data, resulting in long computational time analysis. Therefore, simple aggregation methods are used, among which the test reference year (TRY). In this paper, a comparison between two statistical methodologies for compiling a TRY, the Belgian and the Sandia methods, is presented. Then, the two methods have been utilized for compiling the TRY for the town of Palermo, Italy, and compared both statistically and by means of two simple applications, obtaining …

Validation of a very simple model for computing global solar radiation in the European, African, Asian and North American areas

1990

Abstract In a previous paper Coppolino has proposed a very simple model for predicting the monthly mean daily global solar radiation G (MJm −2 day −1 ) at any Italian location using as input only the sunshine duration s (hours) and the noon altitude of the sun on the 15th of the month h n (degrees). The correlation suggested is G = 7.8 s 0.5 (sin h n ) 1.15 . Herein the validity of this model is verified by extending its application to dat from 24 stations displaced at various latitudes, altitudes above sea level and geographical situations in the European, African, Asian and North American areas. Furthermore the validity of this model to fit the data of the tested stations is compared with…

Global solar radiation in Italy

1978

Ecological aspects of plants inhabiting Mediterranean cliffs. Challenges and prospects of life in vertical environments

2021

[ES] Esta tesis investiga las oportunidades, desafíos y limitaciones para la investigación en el campo de la ecología vegetal, en el contexto de los acantilados mediterráneos. En concreto, las especies casmofiticas, cuyos hábitats naturales se caracterizan por su acusada pendiente. Las laderas de las montañas de piedra caliza en la proximidad del mar, en la parte central y occidental del área mediterránea se consideran objetos de estudio. Los estudios se llevaron a cabo en los cinturones costeros de montaña de las costas del noroeste de Sicilia y la costa diánica en la Comunidad Valenciana. El primer capítulo, titulado "The complexity of environmental factors: cliff microclimate", investiga…

Modelling and analysis of the influence of solar spectrum on the efficiency of photovoltaic modules

2021

Abstract The article presents the influence of changes in the solar radiation spectrum distribution on the properties of various photovoltaic modules, with particular emphasis on the scattered component. We compared the relative efficiency of the photovoltaic modules based on various semiconductor absorbers during bright and sunny, and cloudy summer days. Additionally, we presented the impact of the module tilt angle on the magnitude of the surface incident scattered component and on the efficiency of the module. The solar spectra for various weather conditions were estimated using specialised computer programmes,such as SolarSpectrum or SMARTS2, and we present here the validation results f…

An analysis of direct solar transmittance and atmospheric turbidity in the Mediterranean climatic belt

1989

Abstract The empirical model developed by King and Buckius for the direct transmission in clear sky is applied to hourly data of two Yugoslav locations exhibiting typical meteoclimatic characteristics common to the whole Mediterranean belt. The occurrence of “very clear”, “clear” and “very hazy” hours, after the usually accepted definitions, is determined and discussed. The degree of accuracy of the previsional model is investigated performing the comparison with the corresponding values obtained directly by energetic procedure. A general overestimate of the transmittance is experienced with notable deviations in meteorological conditions affected by the presence of dense clouds which behav…

Phenomenology of maximal and near-maximal lepton mixing

2000

We study the phenomenological consequences of maximal and near-maximal mixing of the electron neutrino with other ($x$=tau and/or muon) neutrinos. We describe the deviations from maximal mixing in terms of a parameter $\epsilon\equiv1-2\sin^2\theta_{ex}$ and quantify the present experimental status for $|\epsilon|<0.3$. We find that the global analysis of solar neutrino data allows maximal mixing with confidence level better than 99% for $10^{-8}$ eV$^2\lsim\Delta m^2\lsim2\times10^{-7}$ eV$^2$. In the mass ranges $\Delta m^2\gsim 1.5\times10^{-5}$ eV$^2$ and $4\times10^{-10}$ eV$^2\lsim\Delta m^2\lsim2\times10^{-7}$ eV$^2$ the full interval $|\epsilon|<0.3$ is allowed within 4$\sigma$(99.9…

A very simple model for computing global solar radiation

1990

Abstract In this paper a very simple model for predicting the daily global solar radiation at any Italian location using as input of a few extensively measured meterological parameters is proposed. In fact the daily radiation G (MJ m−2) is here correlated only with the sunshine duration s (h) and the noon altitude of the sun on the 15th of the month h n (degrees) by the following equation: G= Ks 0.5 (sin h n ) 1.15 where only one value of the factor K is used. The validity of this formula is verified fixing K = 7.8 and using the data from 34 Italian stations displaced at various latitudes, altitudes or geographical situations (inland or coastal site). The test results show that the deviatio…

Outdoor Mean Radiant Temperature Estimation: Is the Black-Globe Thermometer Method a Feasible Course of Action?

2018

Urban planning has become one of the crucial action in order to address and mitigate the effect and the consequences of the global warming and it also entails different sectors of the urban context. The survey and control of the outdoor climatic conditions are among the involved sectors and mean radiant temperature is amid the most analyzed parameters. The aim of the paper is to investigate the effective suitability of one of the most used method in the assessment of the mean radiant temperature, namely the globe-thermometer method, in outdoor urban environment, singling out possible shortcomings and actual efficacy. Specifically, data obtained by measurement campaigns performed by means of…