A plotter for plotting direct and reflected sunlight impinging onto and into buildings

Abstract

To comply with insolation requirements of some countries, recommendations have been made on several graphical methods for estimating the shadow of a building or its features cast by sunlight on other features or buildings on the drawing paper. These methods use a series of graphs for estimating the solar shadow. To many architects, these methods are not easy to apprehend and are time-consuming for implementation. Furthermore, many projection lines will have to be drawn on the drawing paper, causing likely confusion and difficulty in identifying each line. There is now software developed for architects and students to help them design for sunlight impinging onto and into buildings. In the learning process of a person, however, physical tools do maintain their contribution, and complement learning with the computer software. Also in the hand sketch design process of an architect, a simple physical tool speeds up his understanding of sunlight directions and helps him compare quickly options of solar design. In pursuing this complementing contribution of the physical tools, a physical plotter has been invented. This tool comprises a circular solar chart of a selected latitude, a rotatable annular angular scale of glass orientation, and a rotatable instantaneous sunlight path line, all inscribed on thin transparent plastic plates. It enables an efficient plotting of sunlight penetration into buildings, and the shadow of an object, such as the corner of a house, cast by sunlight on the ground, with minimum calculations to be made and lines to be drawn. The invented tool also enables directions of sunlight reflected from glass to be quickly drawn. Penetration and shadow effect of the reflected sunlight can also be plotted then by this reported plotter.