Scope

The RadiCal method developed in the course of this PhD aims to provide an alternative approach that can overcome the shortcomings of currently applied methods to model solar-induced energy flows in field of building science. The novel method is theoretically founded, designed, implemented, tested and validated. It aims to provide a unified and enhanced method for modelling energy flows induced by solar radiation. In order to overcome the limitations of current methods, it is necessary to follow a more general, higher-level approach that allows for more specialized modelling. This can be achieved if light’s electrodynamic nature is considered by applying models of physical optics. At this fundamental level, relevant and seemingly complex processes, which state-of-the-art methods cannot adequately address, arise naturally, e.g. thin-film interference of coatings, angular dependencies or polarisation effects.
However, beyond diving deeper into the physics of light, the method must also meet practical requirements enabling its use in building science frameworks. In particular, this means that on the “input side”, it has to be able to import comprehensive geometries in standard CAD format efficiently. On the “output side”, a straightforward way to integrate the accurate optical information determined within a raytracing process into thermal simulation frameworks is required. In order to achieve this, a novel operator is introduced. It allows the deployment of comprehensive optical data to other applications, particularly for dynamic building performance simulation. The operator’s functionality enables simulation tools to compute solar-related energy flows with raytracing accuracy at virtually no computational costs.
In order to prove the functionality, validity and usability of the novel method, a full software implementation of the RadiCal method is required. This step is essential to demonstrate the feasibility and validity of the developed method. The implemented modules are first applied to validation and test cases at different modelling levels. Afterwards, the method is validated against full-scale measurements on a typical shaded window with triple glazing. A dedicated measurement device and method were developed for this purpose as part of the PhD. Finally, a typical building simulation application case demonstrates the method’s efficiency.
This PhD focuses on the energetic modelling of active and static shading systems, façades and glazings, or, more generally, on calculating all intended and unintended solar-related energy flows relevant to buildings. However, the RadiCal method and the developed software tool can be used in applications beyond that field, e.g. for solar thermal collectors or photovoltaics and, in particular, also for lighting. Almost all methods and models applied here are relevant to the field of natural and artificial lighting. Visible light is, of course, nothing but a distinct range of the entire global radiation spectrum. Since the RadiCal method can consider distinct wavelengths or spectral bands, it is well suited for modelling and studying lighting-related processes. Hence, the method also provides a novel approach to addressing challenging topics in research and practical work in daylighting and artificial lighting. However, due to the considerable effort required to cover the energy-related modelling comprehensively, any daylighting aspects had to be excluded from this work. It will, however, be interesting to exploit this potential in subsequent research.