0000000000217838
AUTHOR
G. Cannistraro
Reduced weather data for building climatization and application to 29 European locations
Abstract A method for setting up a reference year of reduced temperature data, proposed by Klein and Erbs, has been applied by us to 29 European locations for which an official test-reference year is available. This reference year of reduced temperatures may be utilized in computer programs for analysis of the thermal behaviour of buildings. The effectiveness of the method has been tested by calculating the annual energy demand in 29 European locations for three modules with different thermophysical characteristics.
A clear sky atmospheric model valid for the mediterranean zone
Abstract The ASHRAE clear sky model in the version proposed by G.L. Powell has been applied to a set of clear days from two coastal locations of Yugoslavia. The results have provided further elements to confirm the existence of a clear sky atmospheric model valid for the whole Mediterranean zone. This model is characterized by values of the atmospheric extinction coefficient higher than the corresponding ASHRAE ones with upper limits defined by the regression curve derived by using data of Palermo.
The ASHRAE clear sky model. An evaluation in the Mediterranean Zone
Abstract The ASHRAE clear sky model in the version proposed by G. L. Powell is here applied to a yearly set of data for Palermo with small scale time intervals. The model is shown to yield computed values generally higher than the measured ones. New values for the atmospheric extinction coefficient are derived and proposed for the application to the Mediterranean atmosphere. A successful verification is performed using hourly data of Genoa, a location belonging to the same meteoclimatic area.
An analysis of direct solar transmittance and atmospheric turbidity in the Mediterranean climatic belt
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…
A more reliable relation between Angström and Linke atmospheric turbidity parameters
Abstract This work analyses the correlation between Angstrom and Linke atmospheric turbidity parameters (β and T ) which are commonly used in studies about the atmosphere's behaviour since they efficaciously monitor a point turbidity state and model the aerosol attenuation of solar radiation. Starting from the usual linear relation β = a + bT , a more reliable one is here derived by hourly data of three coastal locations with typical Mediterranean meteoclimatic characteristics, for values of the experimental ratios of diffuse and global solar radiation ⩽0.3. The expression found notably differs from the starting one as shown by the time variable.
Notes on the Use of the Tables of Standard ISO 7730 for the Evaluation of the PMV Index
Standard ISO 7730, which is also known as European Standard EN-ISO 7730, provides two alternative methods for the evaluation of the predicted mean vote (PMV) index: a calculation program and a set of tables. In order to use the tables, the operative temperature must be calculated beforehand. The impres sion is given from reading the standard that for a relative humidity of 50%, the two methods are equivalent, i.e. provide the same value for PMV, from the same initial values. In this paper, examples are given showing that the two methods are not equivalent. Differences between them are analysed and a proposal made to introduce an amendment in the next revision of the stan dard.
Algorithms for the calculation of the projected area factors of seated and standing persons
Moderate thermal environments, other than being affected by the mutual radiative heat exchange at low frequency among the internal surfaces, are often characterized by the presence of high intensity sources, that is, radiant sources showing a small area, a high emission temperature and a strongly directional beam. The sun's direct radiation can be considered to be among these radiant sources. In these cases, the computation of the mean radiant temperature and, consequently, the evaluation of the thermal comfort conditions, require knowledge of the “project area factor”, fp, of the subject. Moreover, the fp parameters are also applicable to derivation of the shape factors between subjects an…
Algorithms for the calculation of the view factors between human body and rectangular surfaces in parallelepiped environments
Abstract The thermal comfort conditions for people in moderate thermal environments are subjected to spatial changes, depending on the radiative exchanges of the human body with the surrounding surfaces. Radiative thermal exchanges are notably accounted for by means of the “view factors” between a person in a given posture and the surface of the enclosure. These important parameters can be evaluated by means of a large set of graphs by Fanger, for rectangular surfaces. But the handling of graphs could lead to reading errors. In this paper a simple algorithm is presented, which is able to compute the required view factors. A validation, by means of a comparison against experimental data, is …
THE OPTIMUM SELECTION OF THE WINDOW SHADING LEVELS AND OF THE INDOOR VENTILATION RATES AS A DESIGN STRATEGY FOR BIOCLIMATIC COMMERCIAL BUILDINGS
ABSTRACT Ventilation rates, shading level of windows and indoor air temperature are analyzed together in order to single out the optimum mix referred to the thermal comfort situations of thermally moderate commercial buildings. Thermal comfort is here taken into account by means of the Predicted Mean Vote ( Fanger, 1970 ). A short selection of graphs is proposed, able to provide the simultaneous view of the effects produced, on the PMV, by modifications of the above cited parameters. Graphs can be usefully adopted for the proper design of the glazed surfaces, especially for passive solar buildings.
Simplified thermal analysis of naturally ventilated dwellings
Abstract A simplified comprehensive methodology for thermal comfort prediction in a naturally crossventilated room is described. The methodology mainly consists of the following three steps: • - analysis of the dynamic thermal behaviour of the given room, by means of the admittance procedure; • - evaluation of the air flows rates and their velocities in the room, by means of a new simplified method; • - thermal comfort prediction by means of the Fanger's theory. The results obtained appear satisfactory and the simplified methodology makes itself a useful tool for the identification of appropriate choices at the early stages of the design process, regarding naturally ventilated buildings. Th…