Thermal modeling using equivalent circuits in analogy to electrical circuits is a well-established technique, especially in modeling power dissipation in electronic devices and optimizing cooling means. In building construction and facility energy management, these methods still are rarely found: circuit based models are the exception in this field. The inclusion of thermal radiation effects in energy efficiency optimization - especially for insulation structures - is often omitted, although thermography is widely used. Contrary to pure numerical simulations, equivalent circuit methods allow the derivation of useful formulas and rules of thumb. It might be expected that the thermal optimization of buildings in near future will rely on every percentage of potential savings, so the inclusion of thermal radiation into rules of thumb might be a consequence. In the paper we present a short review on such methods. As examples drawn from current research, we discuss applications in facade and roof construction. While the specific problems discussed here are derived from investigations of energy efficiency in building construction, the focus of the paper is on the applied methodology of thermal modeling and its optical aspects. It is understood as a short tutorial paper.
With the emerging availability of commercial LED based illumination systems, new families of standard specifications evolved. The special properties of LED compared to conventional thermal light sources lead to several new aspects in various fields of standardization and metrology, such as colour fidelity, luminance, problems of coherence and temporal power modulation, connected partially with problems found in laser technology. On one hand, fidelity standards had to be redefined, on the other hand, standards connected with occupational safety and health had to be adapted. Compliance with these standards is ensured by metrology methods and devices, which are subject to standard specifications, too. In the paper, we discuss the conformity of the metrology methods and devices proposed with the standard specification itself; flexibilities in the standard specifications leading to obvious gaps between the metrology and the technical definitions are addressed. Further on, technical simplifications made in the standard specifications are discussed under biological aspects. Finally, in continuation of our investigations on special temporal perception effects, as published in recent years, we discuss some results from spectral analysis in low frequency spectral domain.