Investigation of the Effect of Radiant Heat Flux on Thermal Sensation and Thermal Comfort

• Applicant: Professor Andreas Wagner
• Subject Area: Construction Material Sciences, Chemistry, Building Physics ; Architecture, Building and Construction History, Construction Research, Sustainable Building Technology
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 443126640

Literature studies and preliminary work of our group show that prominent multi-body-part thermal sensation and comfort models do not always account for a precise enough representation of the perception of radiant heat flux from the environment. Particularly under asymmetric radiant temperature exposure, their suitability for evaluating thermal comfort in a space is limited as radiation is the dominant effect on thermal sensation under such conditions. Accordingly, the objective of this project is to better understand the radiant heat exchange effect on thermal sensation at different body parts from a set of experiments and to implement the new findings into an existing comfort model (UC Berkeley model). For this purpose, devices for measuring the radiant heat exchange between single body parts and their close environment were developed and applied to run experiments with human subjects under different and varying environmental conditions. The obtained experimental data were analysed and processed in order to retreive the relevant coefficients for the Berkeley comfort model, respectively its sub-models. The next step will be to fully develop the improved local and body-part-related thermal sensation sub-models, based on further statistical analysis of the experimental data. A set of further experiments fousing on whole-body sensation/comfort perception will be conducted to validate the model. The experiments will be conducted again in the test facility LOBSTER at KIT. Finally, the model will be applied in a simulation case study investigating thermal comfort in a room with varying insulation levels and thus surface temperatures of the exterior building parts, as well as different surface temperatures of the radiant heating/cooling system (floor, ceiling). The cases will include radiant floor cooling in a room with warm wall surfaces, simulating a typical summer situation and radiant ceiling heating in a room with cold wall surfaces, simulating a typical winter situation in a non- or poorly refurbished building. The main focus of this study will be on thermal comfort under temperature asymmetries.

• DFG Programme: Research Grants
• International Connection: China, USA
• Cooperation Partners: Hui Zhang, Ph.D.; Professor Xiang Zhou, Ph.D.