Optimizing Indoor Air Quality with a PID Controller Setup

General
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I’ve been experimenting with optimizing my home’s indoor air quality using a PID controller setup in Home Assistant, and I’m thrilled with the results! Here’s a quick overview of what I’ve done and how it’s been working out for me.

Project Background
Our apartment has a modern balanced air system designed to maintain fresh air while conserving energy. However, keeping the fans running at high speeds 24/7 was both noisy and inefficient. I wanted a smarter way to manage the ventilation, ensuring that CO2 levels stayed within a safe range without unnecessary fan activity.

The Solution
I set up a PID controller using Node-RED in Home Assistant. The system monitors CO2 levels from two Netatmo sensors in the living room and bedroom. The PID controller calculates the required ventilation level based on these readings and adjusts the fan speed accordingly. Here’s how it works:

  1. CO2 Monitoring: The system takes the highest CO2 reading from the two sensors.
  2. PID Calculation: The controller determines the necessary ‘load’ to maintain optimal CO2 levels.
  3. Fan Control: The load value is mapped to predefined fan speeds (Away, Home, Boost), which are set to balance ventilation and noise.
  4. Temperature Scheduling: The system also adjusts the air temperature throughout the day for comfort.

Results
After implementing this setup, I’ve noticed a significant improvement in air quality without the constant noise of high-speed fans. The system adapts dynamically, increasing ventilation only when needed. The graph below shows the CO2 levels (bottom) and corresponding fan speeds (top) over a period, demonstrating the system’s effectiveness.

Challenges and Learnings

  • Initial Setup: Configuring the PID parameters was a bit trial and error, but referencing examples from the Power Saver project helped a lot.
  • Integration: Ensuring seamless communication between the sensors, Node-RED, and the Flexit Nordic CL3 fan unit required some tweaking.
  • Maintenance: Regular monitoring of the system’s performance has been key to fine-tuning it for our specific needs.

Conclusion
This project has been a great way to enhance our living environment using smart home technology. It’s been running smoothly for several weeks now, and I’m excited to see how it continues to perform. If you’re interested in setting something similar up, feel free to reach out for more details!

Happy tinkering! :rocket: