Ever wanted to be able to dynamically fine-regulate/control the water-flow, in your radiators?
[for a number of reasons - see the list below]
i.e. “copy” an Analogue TRV (fx. a Danfoss-RA)?
Living in Denmark, where “remote-heat plants” are common (with a steady amount of hot-water for heating available) - I went ahead with this, using Sonoff’s TRVZB’s.
I consider it a “Pilot/Beta Project” (with lots to be improved & added) - and, I have been “edging” Sonoff (probably annoying them).
…
Because, I “mis-use” the “Opening Valve Degree” command - by using it, to dynamically (in RealTime) fine-regulate/control the water-flow/current coming through the radiator.
The results, can be seen in the attached screen-shots.
[notice: 1) the 1% changes in Valve-Opening, 2) the “extreme” fine room-temperature control (Δ0.18°C, 2. screenshot)].
WHY do/implement THIS?
To stop long radiators from “Banging” (the metal-expand/diminish bearing-noises) - i.e. have a “stable radiator-temperature”.
To have as good/fine Room-Temperature Control as possible.
To avoid returning hot water (which results in “punishment” fees/bills in DK).
To minimize Valve-Noise (the “Weeeeeeee” sound, is reduced to a small “prick”).
To Extend TRV BatteryLife.
To make the “Smart”-TRV nearly as “smart” as an Analogue TRV - in THE PRIMARY FUNCTION OF A TRV: Which is = FINE-REGULATING THE AMOUNT OF WATER, FLOWING THROUGH THE RADIATOR. … Depending On: A) the room-temperature, and B) the selected temperature-treshold.
to solve distribution-challenges, such as: 7A) “the first radiator(s) in a string, getting too much” (leaving too little hot-water /heat to the last ones, in the string), 7B) “low pressure /water-flow” (making it necessary to “spread” the limited amount of flow/throughput out on all radiators).
to inspire Smart-TRV companies, to include this, in their coming Smart-TRV’s (the communication to & with the companies).
to inspire developers & users within the Home-Assistant community, to step in, and aid in the creation of an integration (or extend an already developed integration - fx. “Better Thermostat”).
and finally, Because I am a Regulation-&-Improvement Nerd!
The post above, is on-purpose not about the underlying Automations - and possible Helpers, Integrations, etc.
The Post focuses on Visualizing “the possibilities”, with practical IRL-screen-shots of the “performance /output”!
In the automation behind, the basis is a bunch of chosen temperature-intervals (10-15).
And since I am not a super-user, then I have fx. not used Yaml-etc …
and A LOT of areas-etc can be improved upon - the hardware, the firmware, the automation(s).
and “global variables”, an integration, etc, etc. - are of-course also logical possibilities.
And, I have spend hours, “calibrating” each radiator’s TRV/ventil - starting with finding the percentage, where the radiator-ventil started to open-up for water-flow (fx. at 15% opening),
Followed by a series of increments in opening (fx. 16%, 17% 18%) - and then waiting each time, for fx. 30 minutes, to see HOW MUCH the radiator did “heat up” (fx. “hot from top and 10cm down”).
and finally checking at which “Valve-Opening percentage” the radiator became “saturated”.
and from there, I started “filling in the details” in the intervals … to get the wished-for room-temperature & flow results.
Answer, to paulius2k’s question: “Why is there an inverse relationship between the valve opening degree and room temp?”:
There is “nearly” an inverse relationship:
the Temperature, in itself: The warmer the room gets, the less water needs to (and shall) flow through the radiator. And, if the room-temperature reaches fx. 0.3°C above treshold, then the valve needs to fully close.
and the “Trottle” needed: The more heat, that is lost (fx. because it is freezing outside), the “higher opening value” (the more hot water) is needed, to stay at approx. the same temperature.
…
Illustration - to make it clearer:
It is a bit like the gas-pedal in a car.
uphill, you need to press the gas-pedal further down (add more gas) [to stay at the same speed] - equal to “opening the radiator-ventil more” (higher percentage) [to stay at the same temperature].
downhill, you can remove your foot from the gas-pedal (no gas) - equal to “closing the radiator-ventil”.
and all the way in between (a bit uphill, a bit downhill, and the wind against you, etc.) - you add “just the right amount of gas” [to stay at the same speed].
