WUFI

Do WUFI2d calculate the u-value of the whole construction with 3-4 materials in it.I have seen that WUFI /Pro gives an u- value of the whole constrution in the bottom of the "Assembly" tab.

Any help on this will be appreciable.

Hi Kruti,

the U-value is only useful for describing the thermal properties of a one-dimensional wall; that is, a wall which may consist of several layers but which has the same layer structure for all cross-sections (theoretically extending into infinity). In such a wall the heat flow is the same through all possible cross-sections, and it is always perpendicular to the wall. Under these circumstances, the long-term average of the heat flow through the wall can be described by the U-value.

In a two-dimensional wall, things are more complicated in general. You may have sections with different thermal properties side by side. In this case, you may have some of the heat flowing sideways and other complications. The one-dimensoinal U-value is not really applicable for describing these situations in general, so WUFI-2D does not attempt to determine it. There are other quantities which can be used to describe the "thermal bridge" effects of a two-dimensional wall, and future versions of WUFI-2D may compute and display those. The current WUFI-2D does not because it is mainly concerned with moisture and not so much with heat.

Regards,
Thomas

Thanks for the reply. As I said before that I can see the U-value and R- value in the "Assembly "tab in WUFI Pro, however now when I assemble a new construction with different materials, the value of the U-value and R-value is disappeared. why is that,any ideas?
Thanks for your help in advance.

Kruti wrote:now when I assemble a new construction with different materials, the value of the U-value and R-value is disappeared.

Then WUFI does not have all the information that is needed for calculating the U-value. Maybe a layer thickness is not yet defined, or maybe a layer has no material data assigned yet.

Regards,
Thomas

You have to calculate at least one step, then the new U-Value will be displayed...

Christian

Thanks Christian.