porous wall

Natural Convection in Rectangular Enclosure Due to Flux Density of Heat Prescribed to its Water-Saturated Vertical Porous Wall

Submitted by on Sat, 07/06/2013 - 16:41

Unsteady natural convection in a rectangular enclosure with a vertical saturated porous wall is studiednumerically. The governing equations using Boussinesq approximation for the treatment of buoyancyterm in the momentum equation and the Darcy model are expressed using the stream functionvorticityformulation. Equations are discretized with the implicite finite-difference method. Thomasalgorithm and Gauss-Seidel method are used to solve the resultant algebraic system equations.Results are presented in terms of streamlines, isotherms and isoconcentrations.

Permeation of tracer gases through building materials consequences for ventilation measurements with tracer gas techniques

Submitted by on Sat, 07/06/2013 - 16:36

Tracer gas sorption in and permeation through building materials influence tracer gas ventilationmeasurements. Therefore, it is important to have knowledge about these processes.The permeation of three commonly used tracers (SF6, N2O and the PFT C6F6) through untreatedgypsum board has been experimentally investigated. The result shows that all three tracers diffusereadily through this material (diffusion coefficients in the order of 1 10.-6 m2/s). Caution shouldtherefore be exercised when using tracer gas measurements in rooms with walls of gypsum boardor other porous materials.

Reducing the requirements for ventilation heat through natural ventilation of buildings by use of air permeable porous outside walls. Verringerung des Luftungswarmebedarfs bei naturlicher Luftung von Gebauden durch Verwendung luftdurchlassigkeit poroser A

Submitted by on Sat, 07/06/2013 - 15:50

Calculations show that natural ventilation exploiting wind and specific gravity differences may reduce the need for ventilation heat. This is not done as usual by ventilation through open doors and windows but through fine porous air-permeable outside walls. The optimum thickness of the heat insulation layer is defined, giving maximum saving of total heating and ventilation energy.