Development and validation of a three dimensional thermal transient numerical model with sun patch: Application to a low energy cell

• Published in: Energy and buildings 2015-01, Vol.87 (87), p.425-435
• Main Authors: Rodler, A., J. Virgone, Roux, J.-J., Hubert, J.L.
• Format: Article
• Language: English
• Subjects: Buildings; Computer simulation; Construction; Descriptions; Engineering Sciences; Experimental set up; Low energy; Low energy building; Mathematical models; Mechanics; Sun patch; Surface temperature field; Thermal comfort; Thermics; Three dimensional; Three-dimensional model; Validation; Walls
• ISSN: 0378-7788
• DOI: 10.1016/j.enbuild.2014.11.031

•A refined 3D envelope model is developed and applied to a low energy cell.•Three-dimensional conduction is associated to the sun patch.•The solar fluctuations and minute wise inputs are considered.•The model is validated with the use of an experimental in situ setup. High performance simulation of low energy building requires ever more accurate descriptions of the systems under study to improve the building's performance. This paper describes a numerical model to simulate a single room, using a three-dimensional description of heat conduction in the envelope with environmental conditions that vary over short time-steps are described. The simulation considers the projection of solar radiation through a window onto interior walls. The indoor air temperature is assumed to be uniform. The temperature of the inner and outer surface of the walls are calculated at each time step using a variable-step solver. Validation of the model was carried out using experimental data from a low energy cell operating in a natural climate. A set of well-calibrated temperature sensors and an infrared camera have been used to accurately measure the cell's thermal behavior. Comparison between experimental data and numerical results for free varying conditions shows good agreement and the reliability of the model is proven. These validated results were found for a highly insulated cell. Future studies for different thermal mass cells, with new materials, will be realized to show the contribution of this model. Thermal comfort will also be studied.