Graphic method of calculation of the direct solar radiation received on the facade with available opposing building

Introduction. An approach to the development of a method for taking into account the influence of a single opposing building on direct solar radiation inflows to the building under study, taking into account all the irradiation periods of the facade under study, is presented. When calculating the consumption of thermal energy for heating and ventilation of a building in accordance with the method presented in regulatory documents, it is necessary to perform calculations of heat gain to the building from solar radiation. These calculations are carried out without taking into account the influence of the opposing building, what reduces the accuracy of the results. In foreign and domestic literature sources not found suitable for construction calculations and taking into account all periods of exposure methods. The objectives of this study are: the mathematical substantiation of the method, the possibility of its practical application, the formation of the calculation algorithm. Materials and methods. Calculations of the angular height and azimuth of the Sun by astronomical formulas, trigonometric calculations, construction of graphs of the tangents of changes in solar coordinates from the true solar time are applied. Results. The graphical method is proposed for determining irradiation periods by direct solar radiation of a facade of any orientation. The method is based on consideration of the formulas of the solar coordinates and the location of the opposing building. In this case, the graphic field is used to plot the changes in the tangents of the angular height of the Sun and the tangents of the difference between the azimuths of the Sun and the normal to the surface of the facade from the true solar time. The parameters of the building are applied to the graphic field and, in accordance with the proposed recommendations, the periods of irradiation of the facade are determined. Then the summation of direct solar radiation for the periods of irradiation of the facade is made. The algorithm of calculations on the example of a building in the presence of an opposing building is presented. The decrease of incoming direct solar radiation is shown. Conclusions. The developed graphic method is mathematically justified, has a practical orientation, which makes it relevant to the purpose and easy to use. The calculations for the presented method showed a significant decrease in the received direct solar radiation compared with the calculation without taking into account the influence of the opposing building, which shows the need to apply the method. The implementation of the method will contribute to an increase in the accuracy of calculations of direct solar radiation received on the facade and, therefore, the accuracy of calculations of energy consumption for heating and ventilation of the building.