把光伏余电导向热水罐，而不是以 4 分钱回售电网

自动化 YAML energy-solar-surplus-water-heating.yaml 复制

# HearthNodes recipe 16 - solar surplus to hot water
alias: "Energy - divert PV surplus to the cylinder"
id: hn_energy_solar_surplus_water
description: "Hold grid between -50 W and +150 W by modulating the immersion"
mode: single
max_exceeded: silent

trigger:
  - platform: numeric_state
    entity_id: sensor.grid_power
    below: -250
    for: "00:01:00"

variables:
  band_low_w: -50
  band_high_w: 150
  step_w: 400
  pwm_period_s: 10
  cylinder_c: "{{ states('sensor.cylinder_temperature') | float(0) }}"
  current_w: "{{ states('sensor.immersion_power') | float(0) }}"
  error_w: "{{ states('sensor.grid_power') | float(0) }}"
  next_w: "{{ [[current_w + (band_high_w - error_w), 0] | max, 3000] | min }}"
  duty: "{{ (next_w / 3000 * 100) | round(0) }}"

condition:
  - condition: numeric_state
    entity_id: sensor.cylinder_temperature
    below: 62
  - condition: numeric_state
    entity_id: sensor.battery_soc
    above: 55
  - condition: state
    entity_id: binary_sensor.high_power_appliance_active
    state: "off"
  - condition: template
    value_template: "{{ cylinder_c | float(0) < 62 }}"

action:
  - service: number.set_value
    target:
      entity_id: number.immersion_setpoint
    data:
      value: 62
  - service: script.pwm_switch
    data:
      switch: switch.immersion_element
      duty_pct: "{{ duty }}"
      period_s: "{{ pwm_period_s }}"
      step_w: "{{ step_w }}"
  - service: sensor.record
    data:
      entity_id: sensor.exported_energy_today
      note: "compare diversion against the feed-in rate"

# Grid meter loss -> irradiance-based forecast model, so the cylinder is never
# heated from grid import by accident. Cylinder probe failure stops diversion
# entirely: heating water to an unknown temperature is worse than exporting.