TRNSHD — a program for shading and insolation calculations

For analyzing systems with high solar gains it is important that design tools have a reliable and accurate means of predicting the solar radiation on surfaces. Since solar radiation on a surface is often greatly influenced by self-associated facade obstructions, neighbor buildings and the surrounding landscape, a prerequisite of solar modeling is the ability to predict shaded and unshaded building parts as a function of solar position and geometry. This paper introduces a new simulation program called TRNSHD for external shading and internal insolation calculations of buildings. Although TRNSHD was developed for building simulations with TRNSYS, it is a stand-alone tool that is not restricted to either buildings or TRNSYS and thus can be used to solve other shading problems. The program can handle a large variety of surface shapes as well as beam and diffuse radiation. TRNSHD calculations were compared with other algorithms, measurements and proposed European Standard. The validation shows that TRNSHD functions correctly and that the results of TRNSHD are in good agreement with expected values. A complex shading case study of a building with an atrium has been performed by using TRNSHD. The study gives an example of the use of the program and demonstrates its capabilities.