Create a product system

This code snippet creates a product system that represents the electrolysis of brine and produces sodium chloride.

A product system is built from a reference process — the process that models the last step of your supply chain, or the last step of a specific chain. From there, the auto-linking function connects input and output flows between processes to build up the supply chain. In the script below, brine_electrolysis is the reference process passed to ProductSystemBuilder.

Source: openLCA 2 manual — Creating a new product system

Inputs:

  • 4.2 kg of sodium chloride
  • 42.0 m³ of water (elementary flow)

Outputs:

  • 1.0 m³ of chlorine gas
# get the mass and volume flow properties from the database
mass = db.getForName(FlowProperty, "Mass")
volume = db.getForName(FlowProperty, "Volume")

# create an output product for the process
chlorine_gas = Flow.product("Chlorine gas", volume)

# create a process with the Chlorine gas as quantitative reference with the
# default amount of 1.0 m3
brine_electrolysis = Process.of("Brine electrolysis", chlorine_gas)

# create the input product flows: 4.2 kg of sodium chloride and 42.0 m3 of
# water
sodium_chloride = Flow.product("Sodium chloride", mass)
brine_electrolysis.input(sodium_chloride, 4.2)
water = Flow.elementary("Water", volume)
brine_electrolysis.input(water, 42.0)

# create process for the sodium chloride
sodium_chloride_production = Process.of(
  "Sodium chloride production",
  sodium_chloride
)

# insert the process and the newly created flows into the database
db.insert(
    chlorine_gas,
    sodium_chloride,
    water,
    sodium_chloride_production,
    brine_electrolysis
)

config = (
    LinkingConfig()
    .providerLinking(ProviderLinking.PREFER_DEFAULTS)
    .preferredType(LinkingConfig.PreferredType.UNIT_PROCESS)
)

system = ProductSystemBuilder(db, config).build(brine_electrolysis)

# insert the product system into the database
db.insert(system)

# refresh the navigator to see the new process
App.runInUI("Refresh navigator", lambda: Navigator.refresh())

The ProviderLinking indicates how default providers of product inputs or waste outputs in processes should be considered in the linking of a product system. It can be one of:

  • IGNORE_DEFAULTS: Default provider settings are ignored in the linking process. This means that the linker can also select another provider even when a default provider is set.
  • PREFER_DEFAULTS: When a default provider is set for a product input or waste output the linker will always select this process. For other exchanges it will select the provider according to its other rules.
  • ONLY_DEFAULTS: Means that links should be created only for product inputs or waste outputs where a default provider is defined which are then linked exactly to this provider.

The PreferredType indicates which type of process should be used to link the product system. It can be one of:

  • UNIT_PROCESS,
  • SYSTEM_PROCESS,
  • RESULT.