Simulation Ribbon

The Simulation ribbon includes the following groups:

Before you make the settings in the Simulation ribbon, first select the Simulation node in the Project explorer to which these settings should apply. All settings are saved for the active Simulation node in the project:

Validate

In the group Actions is the Validate button. This allows you to check the model in advance of the simulation. The validation function checks the parameterization and routing to ensure that the operation is plausible, the input time series are synchronous, all pins are connected, and all input data are specified. In this way, errors in the model can be excluded at an early stage.

If errors are displayed, abort the simulation and correct the detected errors.

Notes on the errors are displayed in the validation window.

Detailed information about the errors can be found in the error and model messages in the Simulator window, which opens in the background of the validation window.

The input time series are synchronous if they all have the same time points and the same time zone. The operation is plausible if the nominal capacities of the units are in principle large enough to cover the maximum loads of the demands.

Run the validation again after you have corrected the errors.

The Pause simulation button is used to check all entries without making any changes.

If all validation points are green (see the following figure), click the Continue simulation button.

Filter

You can use the filter to limit the number of time steps to be simulated in order to save computing time. This is useful, for example, to check the function of a newly built model. The reduction of the calculation time is done by a limited simulation period or by a coarser time step grid. The simulation period can be limited by calendar dates or the numbers of the time steps.

First select the filter method from the drop-down list:

With the Calendar method, overwrite the dates directly or open the calendar with the button and select the days for the beginning (From) and the end (Until) of the period to be simulated. Both calendar dates are recorded as the first and last time by the simulation.

With the Time steps filter method, enter the number of the first (From step) and last time step (Until step). For example, time step 1 to 100 can be entered here. Then only the first 100 time steps will be calculated.

After entering the filter data, the entries are converted and also displayed in the respective other unit (calendar date or time step number, see following figure).

In addition, the number of time steps to be simulated can be reduced under Grid by simulating only every xth time step evenly distributed over the defined simulation period. The Grid specifies how many time steps of the time series are simulated. A higher Grid value reduces the number of steps to be calculated and shortens the calculation time. For example, the time grid can be changed from hours to days by simulating only every 24th time step.

Material Properties

For the Material Models, two options are available for selecting how the substance model is to be taken into account in the simulation. The selection is made in each case for a scheme and the components contained therein.

While the Scheme or a component from the scheme is selected in the Project explorer, in the Material properties group of the Simulation ribbon, you can choose whether in the simulation of the energy system of this Scheme

Operational Optimization

In the group Operational optimization, make the settings for the operational optimization.

With the split button Operating costs (a split button always shows the last selected function), you select as Objective function the quantity that should be minimized during the operational optimization.

Specify the Look-ahead and the Result time frame.

Structural Optimization

In the group Structural optimization, the general parameters of the structural optimization are given.

With the split button Annualized total cost, select the size to be minimized during structural optimization as the objective function:

the  Annualized total cost,

the  Investment costs, or

the Net present value.

Calculation Time and Gap

The calculation time is affected not only by the selection of the Solver but also by the setting of the Termination time (the maximum time for solving) and the Gap, which are set separately for Main stage and Pre-stage.

The Termination time for optimization refers to finding the optimum in one time step. Enter the time in seconds. The optimization calculation will be aborted after the specified time if it could not be completed successfully by then. The default settings are 60 seconds in the Main stage and 600 s in the Pre-stage.

The Gap for termination determines the permitted deviation from the optimum solution. The default setting of 0.1 % means that the calculated optimum may deviate from the actual optimum by a maximum of 0.1 %. The lower the gap, the longer the optimization may take. A larger gap shortens the calculation time, but can lead to less accurate results.

If time steps are very unfavorable to solve and require a lot of time, either reaching the accuracy (Gap) or the Termination time is used as abort criterion depending on which criterion is met first. After termination, the Simulator‘s log window shows the Gap value up to which the optimization was solved in this time step, or whether a valid solution was found at all.

Time Series Compression

In the group Pre-stage, use the drop-down list to select the Time Series Compression Level. If you select No compression/exactly, the input fields for Look-ahead and Result time frame are grayed out in the group Operational optimization because the entire simulation period is calculated in a coupled manner.

Status

If the icons in the Status group are colored and high-contrast (and not grayed out), they indicate that