node-red-contrib-heat-curve

Node-RED Heating Curve Node - calculates flow temperature setpoint based on outdoor temperature (Heizkurve).

Features

• Configurable heating curve with slope or design mode
• Night setback (Nachtabsenkung)
• Summer lockout (Sommerabschaltung)
• Two outputs: Flow temp + Heating active boolean
• Min/max flow temperature limits
• Runtime overrides via message properties

Formula

flowTemp = roomTemp + slope × (roomTemp - outdoorTemp) + shift

With setback: flowTemp = flowTemp - setbackDelta

Outputs

• Output 1: Flow temperature setpoint (°C) or null if summer lockout
• Output 2: Heating active boolean (true = heating, false = summer lockout)

Example

slope=1.0, roomTemp=20, shift=0:

Outdoor -10°C → Flow 50°C
Outdoor   0°C → Flow 40°C
Outdoor  10°C → Flow 30°C

With setback (delta=10K):
Outdoor -10°C → Flow 40°C (50-10)

Summer lockout (threshold=18°C):
Outdoor 20°C → Output 1: null, Output 2: false

Configuration

| Property | Description | Default | Range | |----------|-------------|---------|-------| | Mode | Slope or Design | slope | - | | Slope | Curve steepness | 1.0 | 0.2–3.0 | | Design Outdoor | Design outdoor temp | -15 | - | | Design Flow | Design flow temp | 55 | - | | Room Temp | Room setpoint | 20 | - | | Shift | Parallel shift (Niveau) | 0 | -15 to +15 | | Min Flow | Minimum flow temp | 20 | - | | Max Flow | Maximum flow temp | 75 | - | | Setback Delta | Night setback reduction | 10 | 0–30 K | | Summer Lockout | Lockout threshold | 18 | - | | Decimals | Decimal places | 1 | 0–2 |

Input

• msg.payload - Outdoor temperature in °C
• msg.setback - true to activate night setback

Runtime Override

All configuration values can be overridden via msg properties. Setback state is retained until explicitly changed.

| Property | Description | |----------|-------------| | msg.setback | Activate night setback (sticky) | | msg.setbackDelta | Override setback delta | | msg.summerLockout | Override summer lockout threshold | | msg.slope | Override slope | | msg.designOutdoor | Override design outdoor temp | | msg.designFlow | Override design flow temp | | msg.roomTemp | Override room setpoint | | msg.shift | Override shift | | msg.minFlow | Override min flow temp | | msg.maxFlow | Override max flow temp |

Output

Output 1:

{
  "payload": 50.0,
  "heatCurve": {
    "outdoorTemp": -10,
    "flowTemp": 50.0,
    "slope": 1.0,
    "roomTemp": 20,
    "shift": 0,
    "minFlow": 20,
    "maxFlow": 75,
    "clamped": false,
    "clampedAt": null,
    "setback": false,
    "setbackDelta": 10,
    "flowTempBeforeSetback": 50.0,
    "summerLockout": 18,
    "heatingActive": true
  }
}

Output 2:

{
  "payload": true
}

Node Status

• -10°C → 50.0°C - Normal heating
• -10°C → 40.0°C (setback) - Night setback active
• 20°C → locked out - Summer lockout
• -20°C → 75.0°C (clamped max) - Clamped to limit

Use Cases

| Application | Description | |-------------|-------------| | HVAC | Heating system control | | Building Automation | Weather-compensated heating | | Heat Pump | Flow temperature optimization | | Night Mode | Reduced heating at night |

Author

sr.rpo

License

MIT