Nodal network and CFD simulation of airflow and heat transfer in double skin facades with blinds

The paper describes a modeling study of heat transfer and buoyancy-driven airflow in double skin facades consisting of a glass outer layer, a control device (venetian blind) and a double-glazed inner skin. The modeling study was based on two approaches — a component-based, lumped parameter simulation which used a public domain, open source differential/algebraic equation solver and a detailed, CFD calculation which included air flow, conduction, convection and radiation. The primary objective of the work was to compare the performance of the simplified model with the output of a rigorous CFD calculation. A library of basic component models was developed, enabling a flexible approach to be taken to the assembly of system models. The coupling of heat transfer processes with buoyancy-driven air flow was facilitated by the use of an equation-based simulation methodology. Simulation output was compared to experimental results obtained from a prototype section of facade, the performance of which had been characterised in a climatically-controlled solar simulator.