Create constant profile from yearly sum

[SabineHaas]

For some demands we want to use constant profiles, e.g. H2 demand of industry, heat demand of industry (?)

• Write general function that takes a value like sum as input and a constant time series that adds up to sum as output
• test it

@MaGering do I remember right, that you also want to use a constant profile for heat demand of industry?

[jnnr]

We could alternatively adapt the facade class Load such that it assumes a constant profile if None is given. However, I am not sure yet how this can work. It seems that to set the actual_value (fix in solph v0.4), you need to create a sequence of the correct length that adds to 1.

[jnnr]

As an update of the previous suggestion: Instead of altering the logic within the facades, it might be easier to assign profile a scalar value. I just tested this.

Internally, oemof.solph's Flow will create a sequence of correct length. If amount should still represent the sum of the demand, the scalar value should be 1/n_periods.

[jnnr]

Update: You can remove the entry profile under foreign keys in component_attrs.yml to avoid the empty profile being created. Then you can set 1/n_periods as the value for profile in the elements.

[SabineHaas]

When setting 1/n_periods as the value for profile in the elements we have the problem that a leap year needs another value than a non-leap year.

options

• adapt periods in build_datapackage.py when elements are composed and saved
• small script saving time series with all values being 1/n_periods

[SabineHaas]

We voted for option 1: adapting elements.

This means we remove profile from foreign_keys for those components that have constant profiles and add profile to scalars.
The adaption should take place after time series were selected by filter in .yml files.