Building blocks can be divided into any number of zones by drawing partitions inside the block. To start drawing partitions, click on the 'Draw partitions' tool. You can place partitions freely within a block either free-standing or snapped to an external block wall or existing partition. Partitions can be positioned using the snaps, drawing guides and protractor. A partition doesn't need to be snapped to a wall element, you can drag a partition across a wall and when you click the end-point, it will be automatically trimmed to the wall.
You can enter the thickness of the first partition drawn in the block and subsequent partitions take on the same thickness as the first.
See also the Basic Drawing Tools 6 Tutorial Rezoning blocks
Note for partitioning large models
By default, blocks are automatically re-zoned as soon as complete zone perimeters are formed by drawing partitions. In order to speed up the process of adding partitions, particularly in the case of large and complex blocks, the block zoning process can be postponed until partitioning has been completed. To do this, open the Model options dialog and switch off the Automatic block zoning option under the Miscellaneous Edit header on the Drawing Tools tab. When partitioning has been completed, the block can be manually re-zoned by selecting the Rezone block command from the Tools menu. Partitions drawn with the Automatic block zoning option switched off are called Outline partitions and are shown in blue.
Rezoning blocks
When partitions are moved and/or deleted, DesignBuilder attempts to match the new zone geometry with the previous geometry and if it is successful it keeps the previous zone attributes. The matching is done based on overlaps with the floor areas of the old and new zone layouts. After partitions have been moved or deleted the software checks for overlaps in floor areas between new zones and previous zones and if overlaps are found, the attributes are inherited from the previous zones. The exception to this is for detailed HVAC zones where the floor area must match exactly for the new zone to be interpreted as a reworking of a previous zone.
Switching off the Automatic block zoning option can be a big help when rezoning an existing block layout when aiming to maintain zone and surface attributes from the previous layout because it allows the timing of the matching process to be controlled. For example, in the following simple example, if all partitions are first deleted (with automatic block zoning turned on), the resulting single zone will inherit all attributes from the previous zone with the largest floor area and so any subsequently partitioned zones will inherit from that single zone:
However, if "automatic block zoning" is turned off prior to deleting the partitions and the block is manually rezoned after adding the new partitions, the four new zones will inherit from the original four zones:
Click the partition end-point on the outside of the wall and it's automatically trimmed:
When you draw a partition or a series of partitions (stream), you can undo the last point placed by pressing the ESC key or selecting 'Undo last point' from the right-click menu.
You can also terminate a partition stream anywhere by selecting 'End stream' from the right-click menu (or by pressing the ENTER key):
When partitions or partition streams are placed that don't connect with anything at either or both ends, they are called hanging partitions and can be used to add thermal mass to zones:
Once you've placed partitions that divide existing zones within a block, the block is re-zoned automatically:
When you partition complex blocks rather than simple vertical extrusions, partitions are automatically cut to fit within the block:
Tip: If the display of the block outer walls prevents you from drawing partitions (for example in a pitched roof block) then you can switch off the display filled external walls model option.
In some cases, if the geometry is complex, it can be possible to create a zone that comprises several geometric bodies which are physically separated from each other. For example, in the case of a horizontally extruded 'C' shape:
If a partition is drawn as shown:
The partition and resulting zone will be cut to form what appears to be two partitions and two zones:
However the two resulting zones are in fact two geometric bodies within one zone:
While this geometry is perfectly acceptable for the default EnergyPlus solar calculations (see Model Options), it cannot be processed by the more rigourous Full exterior and interior solar distribution option. If this latter option is required, you can either model the geometry as two separate blocks or cut the block.