H. Kerskes, W. Heidemann, H. Muller-Steinhagen

Universitat Stuttgart, Institut fur Thermodynamik und Warmetechnik (ITW)
Pfaffenwaldring 6, D-70550 Stuttgart
Tel.: 0711/685-3536, Fax: 0711/685-3503
Email: kerskes@itw. uni-stuttgart. de, Internet: http://www. itw. uni-stuttgart. de

1. Introduction

The use of solar thermal systems for hot water preparation and space heating in single family houses is the state of art. For further dissemination of solar thermal energy multi family houses and industrial — as well as business-buildings promise great potential. For such buildings solar cooling can also assume importance. In contrast to single-family houses the ratio of roof area to heated space is much smaller for these buildings. For bridging this gap solar active facades are suitable. It is expected that these components will take their part in the future solar market.

In this article the investigation of a solar active glass facade is described. This facade consists of a solar collector integrated into a conventional double-glassed window. To improve the collector efficiency reflector stripes are properly arranged as shown in the figure1. One half of the window area is covered by absorber and therefore diffuse and direct irradiation can still enter a room behind the facade.

Fig. 1 : Front view and cross section of the window collector

Technical advantages of the solar activated glass facade are:

• the use of solar thermal energy,

• controlled room illumination,

• prevention of overheating.

In this project theoretical and practical investigations of the glass facade will be carried out to analyse the thermal behaviour under realistic outdoor conditions.

From an architectural point of view these technical advantages will have to be combined with the aesthetic appearance. This new device fulfils both.

To establish this new technology outdoor measurements under realistic conditions are necessary.