**Mandatory element**

To formulate an equation system inside MOSAICmodeling, you need at least one notation and one equation. In addition, models may consist of a collection of connected equation systems with different notations, functions, and parameter lists. They may also form whole flowsheets with ports and streams. These hierarchical levels will be explained elsewhere. Here, we assume the simplest case.

### Purpose

An equation system is the combination of all your model elements, i.e., notation, equations, functions, etc. It is the element that is then further used in the simulation tab of MOSAICmodeling.

### Explanation of the editor

Figure 1 shows the editor of the equation system. The elements of the editor are explained in Table 1. New elements can be added to an equation system by clicking on “+EQU/EQS” at the bottom. Therefore, you can not only add single equations, but also complete equation systems to a new equation system. Thus, you can strongly modularize your equation system for readability. You could have an equation system that only contains mass balances, equilibria, summation, and energy balances; another that contains your hydrodynamic model; one that contains the thermodynamics, etc.

When you add an element to your equation system, the small window in Figure 1 pops up. At this point, you can select the naming policy – integrate or encapsulate (see connectors) – you want to use for this element. In addition, you can apply a transformation on the element or you can use a connector.

Element | Explanation |
---|---|

File | Filename of your equation system once you have saved or loaded it |

Notation | Specifies the super notation of the equation system |

Description | A description of the current equation system |

Keywords | Optional keywords for your equation system |

Usages | Model elements, i.e., equations or functions, in which the equation system is used |

Connected Elements | Contains all connected elements, i.e., equations or equation systems, that are part of the current equation system |

Functions | Contains all functions connected to the current equation system |

Flowsheeting | Specify the ports and streams for equation system (optional) |

Preview | Preview the current equation system, i.e., take a look at all included equations and functions |

### Workflow

The image below illustrates the workflow to set up an equation system. Below that, you can find the workflow for setting up a flowsheet within MOSAICmodeling.

### Workflow for setting up a flowsheet

In this workflow, all required steps to set up a flowsheet are laid out. The workflow is based on MOSAICmodeling’s capabilities regarding units and streams. The steps are based on the concepts illustrated in the examples for Connectors and Ports and Streams.