[Feature Request] Add Shared Power Group Support for Deferrable Loads

[rwblokzijl]

Problem statement

Many real-world systems (notably heat pumps) act as a single electrical actuator that can serve multiple thermal subsystems (e.g. DHW tank and underfloor heating), but cannot supply them independently or simultaneously beyond a shared power limit.

Currently, EMHASS models deferrable loads as independent consumers. While global grid import limits exist, there is no native way to express:

• a shared power budget across multiple deferrables
• or mutual exclusion / shared-capacity constraints between them

Real-world example

A heat pump:

• max electrical power: 2.5 kW
• serves:
  • DHW tank
  • underfloor heating
• internally decides which mode runs based on setpoints

From a control perspective:

• DHW and UFH are distinct thermal systems
• but they share one compressor
• total power draw must satisfy:

P_dhw[t] + P_ufh[t] ≤ P_hp_max

Optionally:

on_dhw[t] + on_ufh[t] ≤ 1

Current workaround

Users may:

• ignore all other loads, background load and PV
• rely on maximum_power_from_grid to approximate a shared actuator cap
• map optimized thermal states (“predicted temperature”) to setpoints
• configure minimum_power_of_deferrable_loads for both loads such that optimizer actions consistently exceed the heat pump’s built-in minimum-run thresholds

This works in narrow cases, but:

• breaks once PV, EVs, or other loads are introduced
• relies on modeling assumptions outside the optimizer
• makes comparison across scenarios harder

Proposed enhancement

Introduce a way to explicitly model shared actuators, for example:

1. A “shared power group” for deferrable loads:

   • multiple deferrables belong to one actuator group
   • group has a max (and optional min) power
   • optimizer enforces sum of group members ≤ group limit

2. Optional mutual-exclusion constraints:

   • allow users to specify that only one deferrable in a group may be active per timestep
   • or allow fractional sharing, depending on the use case

[davidusb-geek]

Hi, as I see it these new features could be formulated as standard constraints and they could perfectly into the existing architecture.
I don't see why can't implement these.
So two new types of constraints:

• A shared power budget
  • This constraint is easy to implement
• Mutual exclusion
  • For this to work the concerned deferrables should be in semi-continuous mode

We will need new configuration parameters, something like this?

"deferrable_load_groups": [
  {
    "names": ["deferrable0", "deferrable1"], 
    "max_power": 2500,
    "mutual_exclusion": false
  }
]

[OptimalNothing90]

Yes. I do have the same use case and your proposal should solve it.

[rwblokzijl]

Yes i think this should work :)