thermal battery system

Graphixa-style schema for a multi-PID thermal battery system (like those used in large-scale data centers for load shifting) moves beyond simple tag-and-value pairs. It treats every physical component, network packet, and control logic as a node with relational edges.

In this environment, the "Thermal Battery" (e.g., chilled water tanks or phase-change materials) is the core entity, regulated by nested PID loops connected over an IP fabric.

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1. The Knowledge Graph Schema (Topological View)

Instead of a flat database, the schema represents the "Living Twin." Here is how the entities are structured:

Node Types (Vertices)

• Physical Assets: ThermalTank, Chiller, HeatExchanger, Pump.

• Control Nodes: PIDController (Primary/Secondary), LogicSolver.

• Network Nodes: IP_Gateway, Subnet_VLAN, MQTT_Broker.

• Temporal/Data Nodes: Setpoint_History, Energy_Price_Index.

Relationship Types (Edges)

• REGULATES: (PID Controller $\to$ VFD Pump)

• TRANSFERS_HEAT_TO: (Coolant Loop $\to$ Thermal Battery)

• REPORT_VIA: (PID Controller $\to$ IP_Gateway)

• DEPENDS_ON: (Secondary Loop $\to$ Primary Loop Stability)

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2. Multi-PID Interaction Logic

In a thermal battery system (TBS), you have "Cascade Control." Graphixa maps these dependencies so the "Cyberspace" layer understands that if the Primary Loop fails, the Secondary Loop will oscillate.

PID Loop	Function	Cyberspatial IP Role
Primary (Charge)	Manages the rate of energy storage (Charging the battery).	Pushes data to Equitus Fusion for "State of Charge" prediction.
Secondary (Discharge)	Controls flow to data center racks based on IT load.	Subscribes to IT Load metrics via IP to preemptively adjust flow.
Tertiary (Safety)	Prevents freezing or over-pressurization.	High-priority "Heartbeat" over the IP network to a safety PLC.

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3. The Equitus Fusion Integration

By fusing the Graphixa schema with Equitus, the system performs Predictive Re-tuning.

1. Anomaly Detection: If the $K_i$ (Integral) term in the Discharge PID begins to "wind up" (indicating it can't reach the setpoint), the Graphixa engine looks at the TRANSFERS_HEAT_TO edge.

2. Contextual Logic: It identifies that the heat exchanger is fouled or the external IP-controlled chiller is under-performing.

3. Automated Adjustment: Instead of a human technician, the "Cyberspatial" layer calculates a more efficient Setpoint ($SP$) based on the current graph state and pushes it back down via Modbus TCP.

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4. Querying the "Cyber-Physical" State

Using a graph query (like Cypher), you can ask the system complex questions that a standard SCADA system couldn't answer:

"Show me all PID loops whose Stability Index has dropped by 10% following the firmware update on the IP Gateway 'Beta-9'."

Security Layer

Because Equitus/Graphixa tracks the lineage of the data, an "IP Injection Attack" (someone trying to spoof a PID temperature to melt the battery) would be flagged. The graph would show that the reported temperature node is mathematically inconsistent with the Inflow_Sensor and Ambient_Temp nodes it is connected to.