Proposal of a computational tool for generating solar charts and size devices for shading

Abstract

Knowing tools to estimate the Sun's path across the celestial vault helps building designers. Currently, several programs offer solutions that address solar geometry. However, some of these programs require expensive licenses, while some free solutions present weaknesses, such as low-resolution graphics, only one projection system option, a closed-source nature, and difficulties in adding functions and adapting to the operational system updates. Concerning these problems, electronic spreadsheet tools have advantages: many professionals are familiar with spreadsheets; editors allow saving old files in recent formats and make adding modules or functions more accessible. Given the above, the research reported here aimed to develop a tool in an electronic spreadsheet to plot solar charts and size shading devices. A hybrid method was used to develop the tool, with characteristics of the waterfall method (as there is a prior idea of the tool and the steps for its production) and the prototyping method (as it involves tests with prototypes). The development involved steps such as identifying the elements to be represented, choosing projective systems, calculating the apparent positions of the Sun and its coordinates, defining the representation of the horizontal and vertical sections of an opening, and implementing the graphic's controls. The results showed that, in a lightweight file and with a user-friendly interface, it is possible to plot the solar chart, quickly switch between different projection methods and add modules for sizing shading devices.