Time Constraint on Storage Component

abhaybajaj · 26 March 2023 12:54

Hello,

I am working on modelling an energy system where I would like to put a time constraint on the Storage component so that it gets reset to the initial condition after every day or every 24 time-steps.
I am new to implementing constraints in the models. I would really appreciate it if someone could help with the same.

pschoen · 28 March 2023 05:01

Hi @abhaybajaj,

we currently have the option to set the storage balance between last and first time step.

github.com

oemof/oemof-solph/blob/v0.5.0/src/oemof/solph/components/_generic_storage.py#L463


      
              ) * m.timeincrement[t]
              expr += (
                  m.flow[n, o[n], t] / n.outflow_conversion_factor[t]
              ) * m.timeincrement[t]
              return expr == 0
          
          
self.balance = Constraint(
              self.STORAGES, m.TIMESTEPS, rule=_storage_balance_rule
          )
          
          
def _balanced_storage_rule(block, n):
              """
              Storage content of last time step == initial storage content
              if balanced.
              """
              return (
                  block.storage_content[n, m.TIMEPOINTS.at(-1)]
                  == block.storage_content[n, m.TIMEPOINTS.at(1)]
              )
          
          
self.balanced_cstr = Constraint(

I think it is easiest to modify that one. You can then either add that as an additional constraint to a model creating solph (as it is) or you can create an improved version of solph where you replace the constraint by a more flexible one. If you decide for the latter, I’d be glad to provide help to have it in the official package one day.

Cheers,
Patrik