Moisture transfer into a wall in Design Builder

edit

The EnergyPlus engine has hundreds of outputs that can be requested and they depend on the model you have defined.

You can view all available output variables either in the .rdd file or through the EMS scripting add output interface. The step-by-step instructions are described in this knowledgebase article. https://support.designbuilder.co.uk/s...

Depending on the model you use, you may have access to the following outputs:

Zone,Average,EMPD Surface Inside Face Water Vapor Density [kg/m3]
Zone,Average,EMPD Surface Inside Face Humidity Ratio [kgWater/kgDryAir]
Zone,Average,EMPD Surface Inside Face Relative Humidity [%]

Zone,Average,HAMT Surface Temperature Cell N [C]
Zone,Average,HAMT Surface Water Content Cell N [kg/kg]
Zone,Average,HAMT Surface Relative Humidity Cell N [%]
Zone,Average,HAMT Surface Average Water Content Ratio [kg/kg]
Zone,Average,HAMT Surface Inside Face Temperature [C]
Zone,Average,HAMT Surface Inside Face Relative Humidity [%]
Zone,Average,HAMT Surface Inside Face Vapor Pressure [Pa]
Zone,Average,HAMT Surface Outside Face Temperature [C]
Zone,Average,HAMT Surface Outside Face Relative Humidity [%]
Zone,Average,HAMT Surface Inside Face Relative Humidity [%]

Source: https://bigladdersoftware.com/epx/doc...

Also worth looking at the Moisture transfer simulation methods...you can choose to enter data for EMPD and/or HAMT in DesignBuilder: https://designbuilder.co.uk/helpv7.3/...

I'm a BE Consultant and this post piqued my interest in how Design Builder handles this complex phenomenon. As I suspected, it seems to be extremely limited to the least significant mode of moisture migration through building enclosure assemblies (vapor diffusion). If you want a more realistic assessment of moisture dynamics and it's impacts on thermal conductivity and material durability/mold growth, you should have an experienced building scientist run a WUFI model for you. WUFI includes air leakage, wind-driven rain, capillary action, night-sky cooling, solar radiation, etc. into it's analysis and has been field-verified by labs all over the world.