Study On Hygrothermal Performance Of The Slotted Light Steel-Framed Composite Walls In Cold Area

As a building system of energy saving, environmental protection and short building periods on site, light-gauge steel framing has been used widely in residential buildings in recent years. But, since thermal conductivity of steel is high, severe bridge effects are possible. This will result in low temperatures on the inner surface of the wall and cause condensation easily. When this composite structure wall is applied in cold areas, effects of thermal bridge will be more severe. And at the same time people feel uncomfortable due to the strong cold radiation of the wall inner surface. Therefore, it is important to study on hygrothermal performance of light steel-framed composite walls in order to use it in cold areas and to guide HVAC design.In this paper, heat transfer, effect of saving energy and moisure transfer of such complex structure wall has been analyzed using analytical methods of computer simulation, theoretical research and experiment.Firstly, three-dimensional heat transfer models of the composite walls are established. Temperature fields and heat flow of light steel framing walls has been simulated using finite element software of ANSYS. The thermalperformance and the effects of thermal bridges have been analyzed. The research is focused on thermal performance of the slotted light steel-framed composite wall. The influence of perforated parameters (rows of slots, length of slots, width of slots, distance between slots in the transverse direction and in the longitudinal direction) and sectional parameters (stud depth, stud metal thickness, stud spacing and stud flange size) to heat transfer is studied. Based on the simulation above, thermal performance of the walls with the different shapes of the studs, the different thichness of the exterior insulation material, the different kinds of frames, are calculated.Secondly, on the base of ANSYS simulation of heat transfer and the theory of moisture permeation, moisture transfer of the slotted light steel-framed composite wall is calculated in this paper. The factors which affect moisture weight increment of insulation material during heating period, such as kinds of insulated materials, finishing material, indoor environment conditions and...