How Models, Processes and Flows Relate
Understand how Flows, Processes and Models form reusable datasets, and how a model's calculated inventory is saved as a Process for use in another model.
Models, Processes and Flows are complementary core objects. You can assemble a model from processes, reuse a result process generated by an existing model, or start from a flow to find suitable processes to connect.
Three core objects
| Object | What it represents | Relationship to other objects |
|---|---|---|
| Flow | An exchanged substance, product, energy carrier or waste, with its measurement properties | Referenced by process inputs and outputs; also identifies connections in a model |
| Process | An input/output inventory at a specified reference scale, with its documentation | References flows; can be a model component or hold an aggregated inventory calculated from a model |
| Model | Process instances, supply connections, a reference target and supporting documentation | References processes and organizes calculation; results can be saved as new or updated result processes |
Processes are not limited to unit processes. A record can describe a unit process or hold an aggregated supply-chain result. The model preserves the structure between processes; the result process provides an inventory that can be used again.
From processes to a model, and back to a process
Processes A, B, C
↓ Connect through flows
Model M
↓ Calculate for the reference target
Result inventory
↓ Save as a Process
Result process R
↓ Reference as a process
Another model N- Add specific versions of existing processes as model nodes and connect the corresponding inputs and outputs.
- Set the reference process, reference exchange and target quantity to define the calculation demand.
- Calculate the aggregated input/output inventory for that target and save it as a result process.
- Reference the result process in another model to build a larger product system.
A model can generate a primary result and other product results. Check the reference product, quantity and system boundary of the result you select.
The result process and its source model are linked representations. When the source model is retained, you can trace its constituent processes and connections. An aggregated inventory alone cannot reconstruct the complete original model structure.
How the platform currently saves results
Click Save in the model editor to run the calculation and save both the model and its generated result processes. After saving successfully, open Model results to inspect the saved results. Those result processes can also be selected for subsequent models. See Create My Data for the workflow.
If you modify a model without successfully saving it again, existing results still describe the last saved calculation, not the current unsaved edits. Save again and check the results after changing process references, connections or the reference target.
An input/output inventory and life cycle impact assessment (LCIA) indicators are different results. A saved inventory does not guarantee complete characterization-factor coverage for every impact category. Check the coverage notices and LCIA guidance before using the results. A single carbon-footprint value cannot replace a reusable input/output inventory either.
Saving is not publication. Review, publication and access conditions still follow Data Review and Permissions and Data Scopes.
How a Flow differs from an input or output
A Flow defines what is exchanged. A process exchange records the direction and quantity. Multiple processes can reference the same flow with different input or output quantities.
- Product flows describe products, materials or energy exchanged within the technical system.
- Waste flows describe waste exchanges sent for subsequent treatment.
- Elementary flows describe resource consumption or emissions between the technical system and the environment.
Selecting a node's flow port in a model lets you find connectable processes. Matching names alone do not establish compatibility: check the flow identity, exact version and measurement basis, then select a process appropriate to the study's geography, time and technology.
A simplified example
An aluminium-sheet production model references electricity, primary-aluminium and rolling processes, connected through electricity, aluminium and other flows. Calculate for a reference target of 1 kg of aluminium sheet, then save the aggregated input/output inventory as an aluminium-sheet result process.
A vehicle model can then reference that result process for its required quantity of aluminium sheet. The aluminium-sheet Flow identifies the exchange; the Process provides its inventory; the Model retains the structure that produced the inventory. This example illustrates relationships, not verified production data.
When reusing a result process, check which activities its boundary already includes so you do not count those same activities again as additional inputs.
Four kinds of supporting data
| Object | Purpose | Typical place to inspect it |
|---|---|---|
| Flow property | Defines a measurement property such as mass, energy or volume and links to the corresponding unit group | The flow's property information |
| Unit group | Defines related units and their conversion factors, such as kg and g | Measurement definitions associated with a flow property |
| Source | Records publications, reports and other evidence | The model, process or flow that references the material |
| Contact | Records people, organizations and their responsibilities | Dataset responsibility, ownership or administrative information |
These records support interpretation, calculation and traceability. Reuse suitable existing records where possible. Ordinary users who need additional flow properties or unit groups should contact an administrator as described in Data Platform Overview.
Continue working
- Data Platform Overview: distinguish object types from open, commercial, personal and team data scopes.
- Using Data: inspect specific versions, reference and copy data.
- Create My Data: author processes, models and flows.
- Partially Terminated System Modeling: see an example of connected processes forming a model.
Concept references: ILCD life cycle model datasets, openLCA process types, and openLCA flow types.