There is a typical issue one meets when starts to deal with home automation of heating, when multiple zones with TRVs and OpenThem Boiler are involved: calculation of boiler setpoint depending on the conditions in the rooms. This software solves it, maybe in simplistic way, but it does.
Assumption is that all communication happens via MQTT. For defined zones, MZOTBC (later "controller") collects data from thermal sensors. MQTT topics can be either plain text, or JSON formatted. It is possible to have multiple thermal sensors per zone. Then weighted average will be used (by default weights are 1). For every zone controller also watch for current zone setpoints, also per MQTT. Additionally, for every zone, there is defined heating parmeter (either explicitly or default one us used). Yet another source for the calculation is outside temperature, which is also provided on MQTT topic. At the end, for every zone boiler setpoint (target water temperature in heating system) is calculated, which depends on zone setpoint (target temperature in the zone), current zone temperature, current outside temperature and heating parameter for given zone. For calculations, I use some kind of heating curve, partly semi-empirical partly borrowed via reverse engineering. And then, once we know what temperature water is required for every zone, we simply choose maximal and comminicate it to the boiler. Assumption is that TRVs in 'warmer' zones will deal excess of heat. In principal, it is possible to do all kind of smooth transitions, quadratica averages etc. I did them in previous iteration of this software 10 years ago. But, it looks like it current simple approach works reasonably well. Also controller reports back (via MQTT) about zone with maximal boiler setpoint and zone with maximal difference between zone temperature and zone setpoint. Gathering those stats helps to tune heating parameters.
Code is written in GO. You can run it with make run.
You can build your own docker image with provided Dockerfile or simply with make docker-build.
Alternatively you can use docker image available(will be soon) on dockerhub,
and this is recommended way. Addon for Home Assistant is on the way.
There is a example of config file, which must be edited for your case and your zones
and MQTT topics, and renamed to config.yaml.
This was originally quick "one evening prototyping" (which works in my home system for quite some time though). So, don't expect highest quality from the code. It works and that was enough for me :) And while it can be more feature-rich (and one can notice I planned it),I never got to the point to add features I thought I will. As it turned out controller, the way it is now, is enough. Although there are a couple of bells and whistles I want to add, but never get to this point, as I need them only once a year :) But, if you think you want to make it better or add something - submit PR. If you have feature request or find a bug - let me know :)
Code is licensed under terms of GNU GPLv3 License. But if you desperately needed something like this, and you find it covered your neeeds, maybe can buy me beer one day :)