Finite-element view-factor computations for radiant energy exchanges

Abstract

Radiation heat transfer has very many applications within the building services sector. CIBSE Guide A provides the physics background and the relevant mathematical functions for radiant energy exchanges between surfaces of different configurations in chapters 2 and 5. AQ1 The aim of this article is to present procedures for inter-surface radiant energy exchange that range from the most simple (macro-) to most general formulations that are based on a micromesh, finite-element approach. The justification for such detailed procedures and their applicability within the modern building energy simulation software is also covered.

On Radiation-Based Thermal Servoing: New Models, Controls and Experiments

“…The thermal interaction matrix L can now be easily derived by following procedures similar to the ones presented in the previous sections. In Appendix B, we present a numerical study comparing the performance of this method with the standard discrete surface integral [42].…”

“…Since the interaction matrices are estimated according to the view factor, the accuracy and computation time of the approximation directly affects the performance of the system. In this section, we conduct a case study where the standard discrete surface integral (DSI) method [42] and our proposed method are used to calculate the view factor between the bunny object and the circular heat source used in experiments. The center of the heat source is c 1 = 0 0 0 and the center of the bunny object is c 2 = 0 0 5 (measured in cm).…”

Radiation View Factor for Building Applications: Comparison of Computation Environments

“…In radiative heat transfer, the view factor can be defined as the proportion of irradiance, which leaves the emitting surface A 2 and strikes the receiving/collector surfaces A 1 denoted by F A2−A1 . From the mathematical equation of the view factor [11], we may write:…”

“…The present research team had developed a computer code for view factor analysis using a finite-element grid, which can handle an irregular horizon [11]. The software was developed based on a numerical solution of the view factor integral within the Microsoft Excel-Visual Basic for Applications (VBA) environment considering mono-facial solar PV collectors as an example.…”

“…Radiation view factor analysis: (a) Two rectangles with one common edge and (b) the reflecting and receiving surface with uniform grids[11].…”