Description:	A node in a flow network
Detail:

See also Flow Node Property Reference for a detailed list of properties for this class of object.

Related Classes: Commodity, Flow Network, Flow Path, Flow Storage.

Overview

Flow Node works with Flow Path to represent a Flow Network.

The key property Units toggle on/off the Flow Node in the currently executing Model. Additionally the Flow Node must belong to a Flow Network via the Flow Network Flow Nodes membership.

The network flows the Commodity set by the Flow Network object. You can connect Facility and Market objects that produce, consume or trade the same Commodity to a Flow Node and the simulator will connect those activities to the network at that node e.g. a Facility that produces the Commodity will have its Production injected into the network at that node. Note that the Commodity need only be associated with one of the processes the Facility conducts. It does not need to be a product or input to the Primary Process but can be from any of the Secondary Processes.

How to Use Flow Node

The following is a basic guide to using Flow Node:

Create your Flow Network object to contain the Flow Nodes
Create your Flow Node objects and add the Flow Nodes to the Flow Network
Link your Flow Node objects together with Flow Path objects
Connect any Facility, Commodity and Market objects to the Flow Nodes.

Table 1 outlines the function of class of object that connects to Flow Node.

Class	Function
Commodity	Acts as storage for the Commodity. Injection to the storage acts as a 'sink' and Withdrawal acts as a 'source'.
Facility	Acts as either a source or a sink for the Commodity flowing on the Flow Network. Any Process conducted by the Facility that takes the Commodity as input is a sink; and any Process that produces the Commodity as an output is a source.
Market	Acts as a source or sink for the Commodity flowing on the network. If the Market defines either Demand or Price with Max Sales it is a sink; and if it defines Supply or Price with Max Purchases it is a source.

Flow Node Features

Flow Charge places a per unit charge on the Flow through the node. The cost incurred is reported in the property Flow Cost.

Max Flow and its period variants (Hour, Day, Week, Month, and Year) defines an upper bound on the Flow through the Flow Node. Likewise, Min Flow and its period variants (Hour, Day, Week, Month, and Year) defines a lower bound on the Flow through the Flow Node.

Output properties for Flow Node report the Flow through the node as well the Consumption and Production of the Commodity by facilities; and the Sales and Purchases to and from markets. The locational marginal price of the Commodity is reported in the property Shadow Price.

Examples

See the example in the Flow Network topic.

Constraints and Objectives

You can define custom constraints on Flow Node via the Constraints membership. The Objectives membership allows you to include Flow Node coefficients in your multi-objective optimization problems.

Capacity Expansion

Flow Node supports expansion in LT Plan. The key input properties are Max Units Built and Build Cost and optionally FO&M Charge. Expansion costs can be treated as a lump sum or automatically annualized by defining WACC and Economic Life. Units can be built from Project Start Date or immediately if this not defined. Other available constraints related to expansion are: