Add battery efficiency

[lumi321]

Description of the issue

Add battery efficiency to describe how well energy transfer with a battery involved works.

Ideas of solution

battery efficiency: A battery efficiency is the energy conversion efficiency of an electrical energy transfer in which a battery is used. 'process attribute of' some ('electrical energy transfer' and ('has participant' some (battery)))

Workflow checklist

• [x] I discussed the issue with someone else than me before working on a solution
• [x] I already read the latest version of the workflow for this repository
• [x] The goal of this ontology is clear to me

I am aware that

• [x] every entry in the ontology should have a definition
• [x] classes should arise from concepts rather than from words

[l-emele]

energy transfer is defined as: Energy transfer is an energy transformation in form of a spatial transmission, that does not change the types of energies, apart from losses, e.g. waste heat. I don't see how an energy storage process fulfills this definition. But we could define an energy storage process, that is somehow similar, except it is a temporal instead of a spatial transmission. Something like: An energy storage process is an energy transformation that whereby input energy and output energy are of the same type, apart from energy losses.

Then I would introduce a generic energy storage efficiency: An energy storage efficiency is an energy conversion efficiency that describes the ratio between the input and the useful output of an energy storage process. With the axioms:

• 'energy storage process' 'has process attribute' some 'energy storage efficiency'
• 'energy storage process' 'has participant' some 'energy storage object'

Finally I suggest battery efficiency as: A battery efficiency is the energy storage efficiency of a energy storage process in which a battery is used.

[lumi321]

My thoughts were more about the whole process from an outside source into the battery and back to an outside sink (i.e. considering both losses from transfer into and out from the battery and losses from storing).

However, I can agree to separating these two, which is probably the even better solution in terms of flexibility/modularity. The efficiency of the into and out from the battery is already covered by the usual energy conversion efficiency. So, it makes sense to include efficiency for a storage process per se as you suggested.

[l-emele]

Related to this. I just saw that in #839 there are related proposals:

• charging efficiency: the difference between the amount of energy that is put into a machine or battery and the amount that comes out of it when putting electricity into it
• discharing efficiency: the difference between the amount of energy that is put into a machine or battery and the amount that comes out of it when getting electricity from it

[areleu]

This is relevant in the context of SEDOS AP8. Lets see if we can discuss it in the next meeting

[areleu]

energy transfer is defined as: Energy transfer is an energy transformation in form of a spatial transmission, that does not change the types of energies, apart from losses, e.g. waste heat. I don't see how an energy storage process fulfills this definition. But we could define an energy storage process, that is somehow similar, except it is a temporal instead of a spatial transmission. Something like: An energy storage process is an energy transformation that whereby input energy and output energy are of the same type, apart from energy losses.

I don't think charging and discharging are excluded by the energy transfer definition. We have not really a boundary where something stops being a spatial transmission, but since the energy is transmitted from one bearer to another, I would argue that there is already a spatial component. Maybe the solution is generalize the definition of energy transfer. Something like:

Energy transfer is an energy transformation where the energy moves to a different bearer without changing types apart from losses, e.g. waste heat.