I’m not really satisfied with how our Central Heating is functioning. Not that we have technical problems, but the way our house is heated isn’t satisfactory anymore. Maybe it has to do with the floor heating we installed earlier this year; I don’t know for sure – I guess it does, but to make the right conclusions, I need more information.
For example, here’s the chart for the central heating of December 24th & 25th, where you can see at what times and for how long it’s heating the house:
Why is there such a big heating interval in the afternoons? What’s the most important factor, outside temperature or the amount of sunlight? (the latter is definitely of influence cause the living room has a window on the south, measuring 2 x 3 meters…)
Looking at the right side of the chart below, we see the temperature in the living room (the red line) rising to 21.7 °C without any heating (green = thermostat setback):
Free energy from the sun; that’s very nice, but not good for keeping the rest of the house warm..
I really need to create some more insight on all of the factors that influence the behavior of the central heating system.
So that’s what I am doing right now. I’ve added some virtual devices to my Domotica system to calculate some additional values from all the sensors I have.
- Break down total gas usage into 2 parts: gas usage for CH (Central Heating) and for DHW (Domestic Hot Water). I can do this cause my Remeha Calenta tells me whether there is DHW demand or not. This should give me a clearer picture of the amount of gas used for heating; ‘noise’ by someone taking a bath or a shower will be filtered out.
- Average Outside Temperature per day. For this I compared measurements from the nearest KNMI weather station (12 km) with my own outside temperature sensor and didn’t see a need to collect the weather data from KNMI, saving me some additional work. I’m going to use my own sensor for this. This sensor is probably not located at the right height, it’s mounted to a wall of the garage etc. which will result in an offset, but it should be good enough to use.
- Average light intensity in the living room; I have a Lux sensor in the living room and I’m going to use this one to monitor the average amount of light there.
These values should give me a more detailed view of what is happening and how much the influence of both outside temperature and sunlight really is; I know they do, but not how much..
With this I want to be able to explain the behavior of the central heating and explain the gas usage that comes with it.
I started a webpage to do just that. It’s not finished yet; more information will be added like the weighted average of the thermostat setback during a day, average temperatures in the ‘other’ rooms and things like that.
What I really want, is being able to control the temperature per room: the bedrooms, bathroom, my office and the living room. That’s a total of 6 rooms. Looking at how much sunlight influences the central heating, I need a way to deal with that influence; but how? I will probably need to control the amount of heat flowing through the floor heating based on the temperature in the living room, cause when another room is demanding heat, I don’t want heat pumped into the living room when it’s already warm enough!
And I probably also need to control the radiators in the other rooms to get the right temperatures over there, cause I have the feeling that too much heat is going to the living room right now, leaving too little for the other rooms. But first, that feeling has to become a conclusion before I can move forward!