In view of the recent preoccupation at worldwide level, for the integration of the solar systems components within the building skin, we made a numerical investigation in order to assess the opportunity to implement a long string of solar panels along a horizontal or vertical building surface.The study analyses deals with the phenomenon of self-shading, which appears in the case of medium and large solar systems that use solar panels placed one behind the other, along the same row (individual string), but also under the shape of parallel rows (parallel strings). The study creates a mathematical instrument for the evaluation of the shaded surface depending on the location of the panels and the relative position of the Sun. The shading-caused energy loss is analysed along the one-year period, for each of the 12 months, while the panels are considered either placed on a horizontal surface such as a building terrace, or on a vertical surface, such as a building facade. The simulations are made for six Romanian cities located in different climatic zones, characterized by different levels of solar radiation.
The analysis presented in this paper is dealing with the correct and energy efficient measures of cooling buildings through nocturnal natural ventilation. Using this solution is proved in this article to be efficient and can reduce substantially the cooling demand. In order to establish the factors influencing the process of passively cooling a building (the ventilation volume, exterior temperature, thermal capacity of the building, possible duration of the ventilation), we have chosen different buildings, which we have placed them in different temperature zones of Romania. The study is based on multiple simulations realized with a time step of one hour, with the following variations: the climatic parameters, the thermal characteristics of the building, the air flow during night time, the proposed interior temperature. Since the study consisted of numerous simulations, in order to treat the results we have used statistical methods that cover the practical and possible situations, and proved the efficiency of nocturnal ventilation.