Here’s some results from a Particle Photon energy monitor I built for my Passive House.
The main elements are:
- The photon and firmware
- An RHT03 combined temperature and humidity sensor
- An InfluxDB timeseries database and Grafana ( u:guest, p:kingswood) dashboard running on a DigitalOcean virtual machine
- An InfluxDB library I wrote (https://github.com/richardjlyon/InfluxDB)
- OpenUV for UV Index info
- DarkSky.net for external temperature, humidity, and cloud cover
It obtains external temperature, humidity, cloud cover, and UV Index from APIs triggered by webooks. It combines those with the internal sensor data and sends them to InfluxDB. It’s been running continuously for 60 days and seems to be stable.
Here’s a heat map generated from the data - date is left to right, top to bottom is one full 24 hour cycle.
Because the house is so insulated, it warms up 2 degrees around noon, and loses about .1 degree an hour to the environment, so keeps in thermal balance.
The next stage is to hook it into the house Heat Recovery Ventilation system to further optimise energy use based on forecasted external temperature and sunshine. Although the house only uses 15% of the energy of a conventional home, it still uses some and I can reduce that further by getting the Photon to deactivate the MVHR system when sun is forecast.
All very interesting.