Suggested IDD change for ElectricLoadCenter:Storage:Simple

[jmarrec]

Issue overview

In the current form, the idd for ELC:Storage:Simple has absolutely no required fields and no defaults whatsoever. The documentation isn't helping either in this case (for eg it does not specify what it would default to). This makes it a little bit obscure for the user and hard to gauge what values are really needed and what are typical ones.

Details

I would propose the following .idd change, my addition are preceded by a '!'

ElectricLoadCenter:Storage:Simple,
       \memo Used to model storage of electricity in an electric load center.  This is a simple
       \memo model that does not attempt to represent any of the characteristics of a real
       \memo storage device such as a battery.  The type of power, AC or DC, depends on
       \memo the configuration chosen as the Electrical Buss Type in the
       \memo ElectricLoadCenter:Distribution object.
  A1,  \field Name
       \reference ElecStorageList
  A2,  \field Availability Schedule Name
       \note Availability schedule name for this system. Schedule value > 0 means the system is available.
       \note If this field is blank, the system is always available.
       \type object-list
       \object-list ScheduleNames
  A3,  \field Zone Name
       \note Enter name of zone to receive storage losses as heat
       \note if blank then storage is assumed to be outdoors
       \type object-list
       \object-list ZoneNames
 ! N1 , \field Radiative Fraction
       \maximum 1.0
       \minimum 0.0
!       \default 0.0
!       \note This field contains the fraction of storage losses that enter the zone as long-wave thermal radiation.
!       \note This should be a factor between 0.0 and 1.0. The balance of the losses are convective.
!       \note This field is not used if the previous field for 'Zone Name' is left blank.
  N2,  \field Nominal Energetic Efficiency for Charging
       \maximum 1.0
       \minimum 0.0
!       \default 1.0 or 0.8
  N3,  \field Nominal Energetic Efficiency for Discharging 
       \maximum 1.0
       \minimum 0.0
!       \default 1.0 or 0.8
  N4,  \field Maximum Storage Capacity
       \units J
!       \required-field
  N5,  \field Maximum Power for Discharging
       \units W
!       \default XXX or \required-field
!       \minimum 0.0
  N6,  \field Maximum Power for Charging
       \units W
!       \default XXX or \required-field
!       \minimum 0.0
  N7;  \field Initial State of Charge
       \units J
!      \note If blank, will default to the half the maximum storage capacity

Some additional details for this issue (if relevant):

• Defaulting this Simple storage to an ideal case (efficiency for charging and discharging of 1) seem to make sense to me, but otherwise we could pick a closer-to-reality number (80% for example, like in the example files) and also include a \note field suggesting values for typical types of battery (Li-on, Pb-acid, etc)
• Defaulting the initial state of charge to half the (now-required) maximum capacity would make sense (to me at least) and is easy to implement. (somewhere around here, if DataIPShortCuts::rNumericsArgs (7) is empty, then startingEnergyStored_ = maxEnergyCapacity_ / 2 and maxEnergyCapacity_ is necessarilly a number since it's required)
• For Maximum Power for Charging/Discharging, it may need to be a required-field, because I'm not sure there's either a default value (a singe number) that can be set, or there's one that can be calculated from other inputs (maybe we say it can charge in one hour or something but that's arbitrary)
• I tried looking for default values for 'Radiative Fraction for Zone Heat Gains' but couldn't find anything tangible at a first look, but there's probably a better default than 0.
• I would also rename the field "Radiative Fraction for Zone Heat Gains" to "Radiative Fraction" to be consistent with the other objects such as the Storage:Battery and the 3 types of inverters
• Change "Nominal Discharging Energetic Efficiency" to "Nominal Energetic Efficiency for Discharging" to be consistent

Thoughts?

Checklist

Empty for now

[mjwitte]

@EnergyArchmage Would you agree with these proposed changes?