Graphics Programs Reference
In-Depth Information
Figure9.24
Children and parents in systems
There is a pattern in the child and parent formation. The system should
alwaysstartwithachild(forexample,anairterminal)andendwithaparent
(for example, an air handling unit). The child will be a connector whose
flow configuration is set to Preset. A flow configuration set to Calculate
will be a parent. A flow configuration set to System can be a parent or an
intermediary. For example, a chilled water system with multiple chillers will
needsystemconnectorstobeabletodividetheflowbetweenthem,andthey
will still be the parent. Pumps and fans use system connectors because they
will split the flow into two or more paths, each with a pump/fan, and then
recombine it into the single path before it continues on to the parent.
It is not the families themselves that are the child or the parent but rather
the connectors within those families. Generally, the outlet of a VAV box will
be the parent to the diffusers it is supplying, but the inlet will be a child of
the primary air system. A heat exchanger would have inlets and outlets of
both child and parent type. This can be confusing for the user and is a good
reason to make sure the Connector Description parameter is filled out.
