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Node Modeling

The Node device composes a Node model element to represent an electrical bus where multiple elements connect and power must balance.

Model Elements Created

graph LR
    subgraph "Device"
        NodeModel["Node<br/>(is_source, is_sink)"]
    end
Model Element Name Parameters From Configuration
Node {name} is_source, is_sink (from user configuration)

Node is unique among Device Layer elements: it creates only a Node model element with no implicit Connection.

Devices Created

Node creates 1 device in Home Assistant:

Device Name Created When Purpose
Primary {name} Always Junction point for power balance

Parameter Mapping

The adapter transforms user configuration into model parameters:

User Configuration Model Element Model Parameter Notes
name Node name Element name
is_source Node is_source Whether node can produce power (default: false)
is_sink Node is_sink Whether node can consume power (default: false)

In standard mode (Advanced Mode disabled), nodes are pure junctions (is_source=false, is_sink=false). When Advanced Mode is enabled, is_source and is_sink can be configured to create:

  • Grid-like nodes (is_source=true, is_sink=true): Can import and export power
  • Load-like nodes (is_source=false, is_sink=true): Can only consume power
  • Source-like nodes (is_source=true, is_sink=false): Can only produce power
  • Pure junctions (is_source=false, is_sink=false): Power must balance (default)

Sensors Created

Node Device

Sensor Unit Update Description
power_balance $/kW Real-time Shadow price of power at this node

See Node Configuration for detailed sensor and configuration documentation.

Configuration Examples

Single Bus (Most Common)

Field Value
Name Home Bus

Multi-Bus Topology

DC Bus:

Field Value
Name DC Bus

AC Bus:

Field Value
Name AC Bus

Typical Use Cases

Single-Bus System: Most residential installations use one node as the central connection point for all elements (grid, battery, solar, loads).

DC/AC Separation: Systems with DC-coupled batteries and AC-coupled solar may use separate DC and AC buses connected by a converter.

Multi-Site Systems: Large installations may use multiple nodes to represent different physical locations or voltage levels.

Physical Interpretation

Node represents an electrical bus where Kirchhoff's current law applies—total power flowing in must equal total power flowing out at every instant.

Configuration Guidelines

  • Name Clearly: Use descriptive names like home_bus, dc_bus, ac_bus to clarify system topology.
  • Single Node Sufficient: Most home systems only need one node. Don't create multiple nodes unless you have a specific need (DC/AC separation, etc.).
  • No Storage: Nodes have no capacity—power balance is instantaneous. Use Battery elements for energy storage.
  • Connection Target: All other elements (Grid, Battery, Solar, Loads) specify which node they connect to via their connection.target field.

Next Steps