Hi,
For the power consumption I still need to some extra measuring.
The heat in my enclosure was +-1.5°C higher than a sensor without enclosure on 240Mhz
It lowered down to +-1.1 °C on 160Mhz. Unfortunately this is not an constant value as this depends on the room temp. Or I have to design a bigger case where the ESP and DHT are even more separated.
My thoughts was to run an XML/SOAP server or any other usable protocol on the ESP/relay , which receives sensor data from multiple ESP/DHT.
Where the ESP/DHT polls the temp, sends it to the Relay ESP, and goes back to deep sleep.(for example every minute or even longer). This should lower the power consumption to a point where it could operate on a battery. There is a easy to understand guide for how and why: https://www.youtube.com/watch?v=heD1zw3bMhw
As for a radiator head we need an “mini” linear actuator that can be controller by 0-100 value with a small controller; ESP32 or other controller. The radiator has a small metal pin when pushed the valve closes and visa versa.
To drive a small motor we only need a NPN transistor, 1 resistor and one diode. (only on or off type)
If we want to know the position of the motor, we need a stepper motor and this can be driven by a driver on chip, for example the L293 series.
Example of a slightly bigger linear motor.
I have designed some electronic boards in fritzing, but mostly for hobby purposes.
There are also commercial versions of this system. Unfortunately closed, expensive and thus no fun!
https://www.fibaro.com/en/products/the-heat-controller/
These where just some thoughts for a fun hobby project.
PS: name is David De Laet from Belgium.