Mobile sun simulator for outdoor use

• Subject Area: Construction Engineering and Architecture
• Term: Funded in 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 567180597

The solar simulator shall be used for experiments in which a high degree of reproducibility of the experiment is not given when real sunlight in the Central European climate is used. This applies in particular to experimental studies in which the presence of direct radiation is a prerequisite and which require a high number of repetitions in order to be able to evaluate the investigated effects in a statistically reliable manner. It is therefore essential that the radiation emitted by the solar simulator is highly comparable with the direct radiation of the sun under clear skies. The artificial sun is mounted on a mobile trailer so that it can be transported to different locations. A lifting device moves the light source into the desired position on site and a power generator provides the necessary electrical power. Due to its mobile character, the device differs from existing, permanently installed solar simulators on the one hand in its wide range of possible applications and on the other hand in the technical requirements it has to meet. Although it can be used under laboratory conditions, the mobile device is primarily used outdoors. The time and place at which the solar simulator is used are chosen so that there is no additional irradiation from the natural sun in the form of direct radiation at the time of the experiment. The diffuse sky radiation and the long-wave ambient radiation are recorded using a pyranometer-pyrgeometer assembly. The spectral power distribution of the light source on the test object is monitored during the experiment using a spectrometer that covers the spectral range from ultraviolet to near/mid-infrared. The ultraviolet radiation can be reduced to a non-critical level by means of a filter during tests with humans. The mobile solar simulator is intended to enable controlled investigations into the transmission, absorption and reflection of solar radiation in connection with the built environment. Research questions that can be investigated with the requested device primarily include the effects of solar radiation on the thermal sensation of people inside and outside buildings. While other factors influencing thermal comfort are already very well understood, there is still a lack of knowledge about the influence of the spectrum and intensity of short-wave radiation on skin temperatures and the associated reaction of the skin's thermoreceptors. In outdoor areas, it is also important to investigate the influence of solar radiation on the microclimate and the occurrence of local heat islands. In addition, the solar simulator can be used to investigate the influence of solar radiation on the mechanical properties and durability of new (building) materials and on plant-based solutions for improving the urban microclimate, such as green façades.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Mobiler Sonnensimulator mit AM 1,5 D Spektrum
• Instrumentation Group: 5620 Gasentladungslampen für spezielle Anwendung, UV-Strahler
• Applicant Institution: Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau
• Leader: Professorin Dr.-Ing. Sabine Hoffmann