Step 4: Build a Steady State Scenario

In the previous steps of this beginner tutorial, you created a simple mashed thermal network with nine pipelines, two supply points, and six demand points. Now, you will complete the model with a scenario to simulate a possible steady state condition. This step will describe how to set up a steady state scenario and add events in SAInt to influence the model’s behavior.

If you closed SAInt at the previous step and saved your work, you can restart from where you left off by following these steps:

Go to the network tab and click on the Open Open Thermal Network option.
Use the navigation window to locate the project folder C:\ ... \Documents\encoord\SAInt-v3\Projects\Tutorials.
Select the file Tutorial_TNET1.tnet in .\Thermal Networks\Tutorial_TNET1 and click on Open to load the network file in SAInt.

1. Scenario creation

Create a new scenario by going to the scenario tab and selecting New New Thermal Network Scenario. This will open the scenario dialog window, where you will define the parameters and settings of the scenario. The first step is to define the scenario type in the top left corner under 1. Select Scenario Type click on the drop-down menu and select SteadyThermal. Under 2. Enter Scenario Name enter STEADY_STATE as shown in Figure 1. You can enter a short description of your new scenario in 5. Comment. The scenario name will also be used to name the scenario file. In this case, the file will be named STEADY_STATE.tsce. Once completed, click OK at the bottom of the window. A prompt will show up that indicates the scenario was created successfully. Close the window or press OK to continue.

Figure 1. Scenario Dialog window for a steady state case for the tutorial network. Note that the time indicated is irrelevant for the type of scenario selected.

2. Add events for the heat demand points

Once a scenario is available, it is possible to add events. Select the object HDEM.DEMAND3 in the model explorer, and right-click to access Scenario Event Downstream temperature (TDSET) from the context menu as in Figure 2. A new window opens where you can define the properties of the event. Set Value to 35 °C. Leave all other properties to their default values.

Figure 2. Example of how to add an event to a heat demand from the model explorer.

Now select the object HDEM.DEMAND4 in the map window and check the content of the Node Bar. You will see all external and branches connected to the node. In the node bar, select the demand external and right-click to access Scenario Event Downstream temperature (TDSET) from the context menu. In the event properties window, set Value to 30 °C. Leave all other properties to their default values.

Use Table 1 to add all necessary events for the demand points.

Table 1. Details of the events for the heat demand points in scenario STEADY_STATE.
Demand Name	Event	Value	Unit of measure
DEMAND2	`TDSET`	30	°C
DEMAND3	`TDSET`	35	°C
DEMAND4	`TDSET`	30	°C
DEMAND5	`TDSET`	30	°C
DEMAND9	`TDSET`	30	°C
DEMAND10	`TDSET`	35	°C
DEMAND2	`PHISET`	0.4	MW
DEMAND3	`PHISET`	0.9	MW
DEMAND4	`PHISET`	0.4	MW
DEMAND5	`PHISET`	0.4	MW
DEMAND9	`PHISET`	0.2	MW
DEMAND10	`PHISET`	0.7	MW

3. Add events for the heat supply points

Now, we can add events to model the heat supply side on the tutorial network. Select one of the supply points, and from the context menu, choose Scenario Event Heat into the flow (PHISET). Use the details provided in Table 2 to fill in the value and to complete the scenario with all required events.

Once the thermal events are finished, we need to add a reference hydraulic pressure. Select NODE6 and from the context menu, choose Scenario Event Pressure on the hot side (PSET) setting a value of 6 bar-g.

Table 2. Details of the events for the heat supply points in scenario STEADY_STATE.
Demand Name	Event	Value	Unit of measure
SUPPLY6	`TDSET`	70	°C
SUPPLY7	`TDSET`	90	°C
SUPPLY6	`PHISET`	2.4	MW
SUPPLY7	`PHISET`	2.0	MW
SUPPLY6	`PFSET`	1	-

4. Save the scenario data

To save your new scenario, go to the scenario tab and select Save Save Thermal Network Scenario. This will save the scenario file with the newly added events. Alternatively, use the fourth icon from the left at the very top of the SAInt window.