Shared Resource
Overview and Key Concepts
The shared resource object represents a resource that is shared between multiple objects that are not directly connected. It constrains the total flow through these objects, without those objects being directly related in the flow network. Examples of a shared resource can be an incinerator or a flow valve, which keep separate flows separated but impose a maximum total capacity on the sum.
No material flows through the shared resource object itself. Rather, the shared resource is added to the model as a separate object; the objects it restricts (its members) are linked to it through the properties page of the shared resource. All objects for which the inflow and outflow are always equal can be members of the shared resource. This includes pumps, valves, sources and sinks. The sum of all these flows will be enforced to be less than or equal to the maximum capacity of the Shared Resource object. To be able to do this, all members of the shared resource must be attached to the same flow control. Which flow will be reduced first is determined by the order in which objects are attached to the flow control. In principle this decision is made automatically, however it can be influenced by re-ordering flow ports before recalculation of the flow rates.
Properties
The shared resource has three tabs with various properties. The last two tabs are the standard tabs that are common to all fixed resources. For more information about the properties on these tabs, see:
The properties on the first tab, Settings, are as follows:
Control
This setting is described here.
As remarked above, the shared resource can only constrain objects which are all connected to the same flow control. The shared resource must also be connected to this flow control, so that it can take into account the constraints when building the flow network model. Multiple shared resources can be connected to the same flow control.
Maximum capacity
This is the maximum total flow that is allowed through all attached objects. The shared resource will add a single constraint to the flow network optimization model for the sum of the flow through all these objects.
Resources
These are the objects that are constrained by the shared resource. You can add them using the green plus button and selecting specific objects or object classes in the model, or you can use the sampler to click an object in the model. An error message will be shown for each object that cannot be a member of the shared resource.