Overview of thesis structure

Figure 1 provides a graphical overview of the thesis chapters with regard to the objectives formulated in section 1.2. Chapter 2 highlights the main methodological approaches followed in the course of the thesis. Due to the nature this PhD, the subsequent chapters also contain essential methodical elements. As the thesis comprises multiple, separate theoretical and empirical components (see Figure 2), it seemed more appropriate to include theory, methods, implementation and tests or validation as sub-chapters within the relevant chapters.

Chapter 3 discusses the current state-of-the-art. It focuses on the currently applied methods and models comprising modern approaches and the methods specified in international standards. The chapter also covers a discussion of the limitations that arise from the models used.

Chapter 4 covers all methods and models that are in this PhD used for modelling solar radiation, propagation of light and scattering of light. As mentioned above, the chapter contains not only the models but also the relevant theory, their implementation in the context of the developed method, as well as validation and testing results. In order to address the complexity of the field of optics and light, the chapter also provides a broader view of physical optics and discusses the relevance of scattering processes that are not part of the final method. Providing this broader context is essential to show the relevance and limitations of the applied light scattering models. The chapter starts with Introduction RadiCal, D. Rüdisser 5 a brief summary of the history of light. It primarily addresses objective 2 of the thesis, but also objectives 1 and 4.

Chapter 5 covers three essential components of the developed method that are not directly related to light and optics. First, a short overview of the principles of Monte-Carlo methods is provided. Afterwards, the related optimisation method, simulated annealing, which is applied for several tasks in this work, is briefly introduced. Finally, the chapter concludes with a description of the geometric Fibonacci algorithm and its implementation. The chapter addresses objectives 2 and 4.

Chapter 6 addresses objective 4 by introducing a novel concept developed in the thesis and referred to as solar incidence operator (SIOP). The operator represents an efficient method to deploy raytracing results to other applications, particularly dynamic building performance simulation. The first part of the chapter introduces the definition of the operator, whereas the second part focuses on its application, i.e. its evaluation based on different irradiance models.

In chapter 7, the physical models and methods of chapter 4 and the stochastic methods of chapter 5 are applied to establish a full-spectral Monte-Carlo raytracer. The raytracer is then used in an angular scanning mode to measure and extract all relevant optical characteristics of target objects (e.g. glazings) required to derive the corresponding accurate energetic models.

In chapter 8, the entire workflow of the developed method is validated against empirical data. The transmittance of a shaded triple-glazed window has been measured for several months in various configurations. The developed method is then applied to a detailed CAD model of the window to derive the corresponding solar incidence operators. In a digital-twin approach, these SIOPs are subsequently used to perform virtual measurements in the model. The computed transmittances are finally compared against the measured values.

Chapter 9 demonstrates the potential and performance of the method based on a typical application of dynamic thermal building performance simulation. A shaded window’s energetic key performance figures are determined for various orientations and locations. All relevant energy flows are determined using a transparent simulation model designed explicitly for that purpose.
Important aspects of the developed method, its potential and limitations as well as the results of the performed validations are discussed in chapter 10.

Chapter 11 finally provides a summary, key findings and an outlook regarding future work.