GMI / IMBA Building, A

Investigation of thermal comfort in the atrium and meeting zone

Project Information
ClientATP Wien Planungs GmbH / Errichtungsgemeinschaft IMBA GmbH – GMI GmbH
LocationWien, AT
Built Volume n/a
Project Duration 2013-2014
Project Team Florian StiftMichael Haugeneder

The previously unused atrium of the GMI/IMBA building in Vienna was to be thermally refurbished and used as a meeting and events area. The large proportion of glass in the atrium led to the danger of overheating in summer and, hence, a failure to meet the comfort criteria set out in DIN EN ISO 7730. In order to evaluate the many influences, a dynamic simulation was used to study this thermal behavior. A flow simulation envisaged a range of extreme situations as a way of investigating the development of uncomfortable cold air flows and asymmetric temperatures.A range of shading systems, glass types and ventilation strategies was also investigated by a dynamic simulation which modeled every hour for an entire year.The simulation calculations showed that the thermal comfort of the atrium could be best established by the use of electrochromic glazing. The advantage comes from the fact that, although the panels have a very low g-value when they are dark, their transparency is largely unaffected. In addition to this, the maintenance costs of the shading system could be reduced to a minimum. Motor-controlled flaps in the façade and smoke extraction equipment on the roof were also used to create natural ventilation as a means of removing the warm air from the upper part of the atrium.Highly glazed building elements can suffer from low internal surface temperatures in winter which can be regulated by the quality of the chosen glazing panels. Downdrafts of cold air on the inside of the façade can also arise which reduce comfort in the meeting area. In addition to this, warm air in the top of the atrium and heated surfaces in the summer months can lead to an asymmetrical distribution of temperatures which also has a negative effect on human comfort.A thermal simulation designed to model the edge conditions produced a flow simulation for the atrium.Simulation calculations enabled the influence of the various types of glazing to be investigated with the aim of avoiding downdrafts of cold air on the inside of the façade. The flow simulation showed that asymmetrical radiation temperatures could be largely avoided by adapting the internal façade in the meeting area as a means of reducing the surface temperatures.


IMBA/GMI building with south-facing atrium
IMBA/GMI building with south-facing atrium
Scheme of openable flaps for natural ventilation during night hours
investigated variants of the dynamic simulation
Air velocity distribution in the atrium
Air temperature distribution in the atrium