Re: The arch
Yes the arch can be modeled in HB-Energy. The best approach is probably to break up your extruded geometry into discrete floor, wall and roof geometries that can be defined as Honeybee Face components with manually defined, corresponding
Re: Simulation of wind and radiation:
If you want to use an energy simulation to model thermal comfort, I think an always-open window model would capture an open enclosure adequately. An airwall is typically used to delineate interior boundaries so would not be appropriate for your exterior boundary. I would double check the way the selected solar radiation (i.e.
FullInteriorAndExteriorWithReflections for shading) and airflow (i.e. simple wind speed-based airflows versus a wind pressure-based Airflow network for ventilation) is modeled in the EnergyPlus references just to ensure you understand what abstractions are being made. There are increasing computational costs associated with increasing model realism that may not be worthwhile to pursue at an early stage.
I would suggest using Radiance for modeling the short-wave solar radiation impact on comfort, like in the
UTCI Comfort Map component. That way you can capture the diurnal swing of the concrete platform’s thermal mass with EnergyPlus, while incorporating the detailed short-wave radiation dynamics of Radiance. Since there’s no glass, you don’t even need to consider the portion of short-wave radiation that is absorbed by windows that (I believe) doesn’t get modeled by the Radiance model.
Edit: This paper by Chris, Theodore G., and Mostapha actually answers your second question in a lot more detail: https://www.ladybug.tools/assets/pdf/BS2017_260.pdf.
 Face - Honeybee Primer
 EnergyPlus Web-Based Documentation | Big Ladder Software
 UTCI Comfort Map - HB-Energy Primer