A program for the calculation of
For customers of AnTherm/SolRad there is now the possibility to evaluate the influence of solar radiation and the long-wavelength radiation to and from the external surfaces of a building construction with regard to thermal transmission and temperature distribution.
Since the influences of the radiations are dependent on their orientations, there can be several „exterior spaces“. An exterior space could, for instance, be subdivided into the spaces „south wall vertical“, „west wall vertical“ and „oblique roof“. In the course of the evaluation, three diurnal variations of the radiation air temperature and the related thermal transmission resistances are assigned to these three spaces.
The radiation air temperature is a fictional temperature which is influenced both by the solar radiation and the long-wavelength radiation exchange. If an AnTherm user specifies the radiation air temperature instead of the exterior air temperature, this means that not only the diurnal solar radiation is considered but also the long-wavelength radiation exchange between the exterior surfaces of the exterior building components on the one hand and the sky and the terrestrial environment on the other. The use of the radiation air temperature implies that the absorption and reflection processes occur at the exterior building component surfaces. The used method is capable of exactly reproducing these processes.
Until now, the user specified outside air temperatures in AnTherm as exterior boundary conditions. In the stationary case, this is a single value. In the instationary, periodic case this is the 24 values of a diurnal cycle.
SolRad Version 4.1 or higher and AnTherm Version 9.136.2 or higher are now connected via an interface. The diurnal variations of the radiations computed by SolRad (global radiations in Wm-2) at the project site can be exported from SolRad for a chosen date and orientation by clicking the „Export“ button. These exported result files can then be imported in AnTherm in order to compute radiation air temperatures and thermal transmission resistances.