Analysis of the transient thermal behaviour of a solar honeycomb (SHC) facade element with and without integrated PV cells

作者：Brandl D^*; Mach T; Hochenauer C

来源：Solar Energy, 2016, 123: 1-16.

DOI：10.1016/j.solener.2015.11.004

• Ventilated facade element
• Solar honeycomb
• Natural convective flow
• Transient thermal behaviour
• Computational Fluid Dynamics

The transient thermal behaviour of a ventilated solar honeycomb (SHC) facade element was investigated with the help of numerical simulations. Therefore two three-dimensional CFD models were used to consider a SHC facade element with and without attached PV cells at the exterior glass pane. Beside a natural convective flow model also a radiation model with two wavebands was implemented to enable the differentiation between short-wave solar radiation and long-wave thermal radiation.
In a laboratory experiment temperatures in the ventilation cavity and the heat flux at the rear wall of the SHC facade were monitored and compared to simulation results.
The experiment using a solar simulation device was carried out for one facade element with PV cells at the exterior glass pane and for one facade element without PV cells.
The time-step size for the transient simulations was dramatically reduced after the determination of the maximum time-step size, which finally enabled the analysis of the thermal behaviour over a prolonged period (one day or longer) within reasonable simulation durations.
Moreover, the impact of the SHC's material properties on the dynamic thermal behaviour was analysed with the three-dimensional CFD-model. Differences in heating rate, heat flux and temperatures were determined and compared by using five different materials instead of the cellulose honeycomb.
Finally this study obtained the impact of hourly changing external climate conditions on the thermal behaviour of a single 1 x 1 m SHC facade element using climate data from a cold winter's day and a hot summer's day which were measured in Graz, Austria.

• 出版日期2016-1