I cannot find asnwer on question: is multi-zone heating (temps set for each room individually) possible together with modulated control of heating? Or it can be achieved only with on/off heating?
Modulated heating can take external temp into account while on/off cannot.
Currently I have zigbee zmart TRVs on my radiators, being able to somehow limit temperatures in each room. But I’m not able to send command to heat only those rooms since it’s controlled by central thermostat in a leavingroom
I’m really struggling with find optimal solution. I’m about to change boiler. But seems that in my country OpenTherm is not so popular. Of course there are bridges etc. If posisble I would like to stick with factory solution. But even Vaillant itself has at least 2 or three platforms ( I mean applications, system of remote controls) depending on gateway installed. Obviously gateway means cloud. But I can plug into boiler’s bus directly. It doesn’t solve communication with TRVs which are controlled by a control console
That’s not true. Modulation means that the intensity of the flame can be adjusted, the power of the boiler.
The external temperature has a relation to the temperature of the water. This can be achieved with an on/off heater as well, it will just switches on and off (a bit like PWM modulation).
My heater (Vaillant) does exactly that.
Thinking about it, I should be able to dynamically adjust the power through ebus depending on OAT.
I was just looking at zigbee TRVs to extend my current solution to all of the remaining radiators in my house, and noticed your post. Certainly this BLE solution looks attractive and it is supported out-of the-box, I would be curious to know if it works equally out-of-the-box through a BLE proxy. Another question is where you could find them so cheap, they seem to be comparable to zigbee ones in the shops where I was able to find them… Thanks!
The point is that on/off is less efficient and less comfortable (under/overshooting) than constant modulation. And impacts service life. PWM would kill the heater (I’m aware you applied a loose comparison here)
Just don’t know how heater target temp changes when different rooms require different temps. I would like someone could confirm that constant modulation (without on/off modulation) is possible and applied by some factory brands
I have not checked lately. I bought my last batch last winter, so before the war and crisis.
If they have increased significantly in price, then maybe this approach does become much less attractive. Especially since you need an ESP32 running Tasmota as a proxy.
In that case wifi TRVs might be more interesting.
EDIT: just checked and indeed, prices have skyrocketed. Even second hand prices exploded.
Maybe I should think about selling mine and make a nice profit
Hello, we have central heating and Fritz301 valves in the individual rooms.
The controls night/at home or not/windows open work. We also have temperature sensors outside.
Now I am looking for a control that switches on the heating depending on the outside and inside temperature so that it has 22 degrees in the kitchen at 6.00 am, for example.
With the normal “switch the heating to 22 degrees at 5.00 a.m.” automations, the advance can be very inaccurate and waste energy.
I think I saw something like this somewhere, but can’t find it anymore.
Can anyone give any help on this?
What is the point of a PID control for me?
Hello niemehrarbeiten (like your name, very much on board with that motto ),
PID is what you are looking for. Just google it, it’s too complicated to explain here.
However you are limited by the inner workings of the Fritz valves. PID is probably not going to work with them, here’s why:
The output of a PID system is basicly a value which tells the device at which capacity it should be running to get to a target as quickly as possible, without overshooting.
The only value you can adjust on your Fritz valves is the temperature, which you want fixed at 22°C.
The inner mechanism of the Fritz valves (or any radiator valves for that matter) only know two states; ON whenever the temperature isn’t reached yet and OFF when the temperature has been reached.
To avoid the valve continuesly switching between ON and OFF you would usually use a hysteresis value (this is probably build in allready). This means the valve will turn ON at lets say 21°C and turn OFF at lets say 22.5°C.
Thank you very much for the answer. I have installed the PID thermostat as a test. I’m not quite sure how to integrate it yet, but I will integrate it into the automation as a climate switch.
I bought the recommended aqara device, but I fortunately it doesn’t work at all using ZHA. Beware other buyers, the blog post is incorrect, it does not work native with home assistant zigbee at the moment.
Radiator valve heads are certainly not ON/OFF switches. The Eurotronic valves I mentioned earlier in this thread can do anything between 0% (fully closed) to 100% (fully opened), and I’m quite sure the Fritz valves do the same. With Zwave-JS the Eurotronic valves also report the current valve open state between 0 and 100 (and AFAIK they’re the only brand doing that), and you can even set the state.
The Heimeier and Danfoss thermostatic “dumb” valve heads that were originally on the radiators do exactly the same by nature: their wax motor has continuous states between fully closed and fully opened. See Wikipedia for an explanation.
WRT a PID controller, it can work with ON/OFF style actuators when you control them using pulse width modulation (PWM). The PID controller has to be a lot slower than the PWM for that to work, though, and the actuator should be able to handle being PWM controlled.
To save energy on heating first it will be nice to start with some non smart things like doors and windows. I replaced all gaskets on my pvc doors and windows. It helped but I realized that it is possible to install third gasket into the window/door frame. Pvc/upvc by design are mostly 90% efficient on air leakage. But with third gasket installed into frame it became much more efficient in terms of air leakage. I wont say it 100% efficient but it is close.
Next step will be tuning your boiler or furnace to work as efficient as possible with your house. This can be done in installer mode. I don’t know for every appliance out there but I know that some settings on my buderus, especially heating curve, can have big affect on heating and gas usage.
The next thing is hot water. My furnace is using around 30% of gas usage just to keep hot water in water tank every day on 55 - 60 degrees. So I manually set it to 35 during the day as no one is using hot water. When I need it I crank it up.
The last thing is smart trv. This is my first winter with five of them and I’m still testing.
It is possible to lower energy consumption but this is doable to some extent. It’s like you are trying to get your car to consume 3 liters of fuel on 100 km although factory made it to consume 6. It’s not possible without major investment.
I think your hot water supply should remain at 55 - 60 degrees on account of preventing the Legionella bacterium to grow (which causes Legionnaires, severe pneumonia).
If your home’s water comes from the public network there is not much to fear. It is easy to check your free chlorine at the faucet furthest from the hot water source. If it is on the normal scale, you only need to do a high temperature disinfection once a year, chlorine is added for a reason.
An aerothermal machine is very inefficient raising the water above 50ºC, an energy waste to do it daily 365 days a year for fear of something non-existent.
I have radiators in my house and they have water form a public network in it. Every year I have to add water to pressurize radiators and vent them as air is trapped in system. And I have to do it a few times a year, especially during the winter season.
If the water from public network is contaminated I will have to do it with gas mask or I will get sick from water mist coming out from the radiator vent.
What has surprised me is the number of replies that stated members were heating their house/room temperatures above 20c
A good way to save on energy costs is to turn down the thermostat. Even one degree will see savings in cost without too much of a noticeable difference to overall heat.
For some context, the wife and I live in a detached three story four bedroom house. We heat all the rooms, and room doors are left open. The TRVs are ‘dumb’ and set according to room use e.g. lower in the bedroom. The wife works from home so there is someone in the house 24/7.
We have a gas boiler and hot water tank, with the heating control set to constantly on. The house is not zoned with three ‘dumb’ radiators on each floor in the hall. The thermostat is situated downstairs by the front door and therefore affected by the door opening and closing.
Our thermostat is set to 17.5 degrees during the day and 16.5 degrees at night (8 hours). Rarely is the thermostat turned up unless it is cold outside (-2c). Other than that jumpers are used when feeling a slight chill. That is less than often.
Compared to some mentioned temperatures in this thread I must be saving quite a bit on the energy costs. That I think is smart.
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