Adjacency

Construction tab in model data under Construction header

The adjacency of individual surfaces can be set to be either adjacent to ground or adiabatic. The adjacency data is used at the surface level, though defaults can be set at a block and zone level as well if all surfaces in a block or zone have the same adjacency.

The full range of options are:

1-Auto - the adjacency of the surface is determined automatically by DesignBuilder based on its position. External surfaces below the ground plane are, by default, considered to be adjacent to ground and external surfaces above the ground plane are considered to be adjacent to outside conditions.
2-Not adjacent to ground - the surface is not adjacent to ground even if it is situated below the ground plane.
3-Adjacent to ground - the surface is adjacent to ground even if it is above the ground plane or it is an internal surface.
4-Adiabatic - the surface is adiabatic. This means that heat is not transferred across in its external surface. Adiabatic surfaces are frequently used in thermal modelling to represent surfaces which are between two zones at substantially similar conditions. Note that thermal mass is still modelled in Adiabatic surfaces because heat can still be transferred into the mass through the internal surface. Adiabatic surfaces are often used for modelling the boundary between the actual building model and any adjacent buildings which are not to be modelled.

You can determine which surfaces are adiabatic or adjacent to ground by looking for the corresponding surface adjacency markers in the Edit Screen at zone and surface levels:

Note that the recommended way to set ground and adiabatic adjacencies is to use component blocks.

Adiabatic surfaces use internal constructions:

Adiabatic external floors use Internal floor construction.
Adiabatic flat roofs use reversed Internal floor construction.
Adiabatic external wall surfaces use Internal partition construction.

You can find out the construction that will be used for each adiabatic surface by looking at data on the Construction tab at surface level.

Note that in the current version of DesignBuilder the Visualisations shows adiabatic surfaces using external surfaces properties but internal surfaces (Internal floor and partition constructions) are used in calculations as described above.

Exclude this surface area from total zone floor area?

When modelling situations such as offices space within large warehouse zones where the ceiling at the top of the offices is not usable floor area in the warehouse it may be useful to exclude the area of any unused floor surfaces from the floor area of the zone.

So for internal floors such as the unused 'floor' on top of the office space you can check the Exclude this surface area from total zone floor area? checkbox to ensure the floor is not used in the calculation of zone and building floor area and in the calculation of internal gains where defined per m2 or per ft2.