heating - spring is here...

[Andras]

Hi,

My Loxone setup has been running good since the start of the heating period, and it's now only programmed for heating, so I don't yet have a good setup for controlling winter/summer transitions. What is a good way to control IRC, ITC, CC?

In my location we typically have a few months transition period when neither heating, nor cooling (A/C) is used.

My thoughts so far are in a rather manually controlled direction:

• Add two "settings" switches with remanence: Heating on/off, cooling on/off
• Set IRC heating mode (auto cooling, auto heating) according to these switches
• When both switches are off, set an operating mode ("transition phase") and set IRC to Off through schedule
• ITC and CC need no modification

Any recommendations for a "better" program?

[Duncan]

sounds fine - use a custom operating mode to set the IRCs to frost protection temperature (off)  and add to each IRC schedule, then you dont even need the 2 switches - this keeps the IRCs learnt behaviour for the next heating period

if you create another operating mode called boost, and set this to say comfort temperature, you can add this above the OFF operating mode to some of the rooms eg living spaces, then enabling this via a timer gives you a timed heat boost during those transition times.

i have 3 OFF operating modes - one for down, one for up (bedrooms) and one for bathrooms - enable each to set the associated IRCs to standby/off/frost protection

i then have a spring/autumn setting where living spaces and bathrooms arent disabled, and a bathroom only setting where the up and down are disabled but not the bathrooms, then finally summer with all 3 modes enabled, settting the IRCs to frost protection.

[Rob_in]

Hi,

What kind of heating system have you got? And what sort of monitoring/control?

We are in a mountainous area so the weather here is quite changeable and as such you cannot simply go by dates for what should be happening. We have wet underfloor heating/cooling so it's slow to react (around 3 hour response) so good planning is key to avoid under/overshoots. We have a KNX interface for the boiler (air/water heat pump) which gives loads of data useful for monitoring/control.

I'll try not to go into too much detail here because I'm a software developer and probably have made the control slightly over-complicated... but it does work very well ;)

The most useful part of our climate control setup is having a decent weather forecast. Used to use Wunderground but now use Darksky. There's a thread about Darksky in this group and I find it works well. I also calculated the heat gain/loss envelope of our house so have a 24 hour indoor forecast based on that and the outside forecast. It's pretty accurate and this way we know in advance when the house will drop below a desired setpoint hours in advance.

Basically we have modes which are set by looking at the maximum outdoor temperature that's forecast in the coming day.

- Cooling when outdoor max forecast > 27C

- Heating 'Eco' when max < 19.5C

- Heating 'Comfort' when max < 16.5C

- Heating 'Comfort+' when max < 11C

Eco and Comfort are Loxone concepts so pretty self explanatory. Comfort is supposed to be when we are home and not sleeping. In this mode the heat is backed off slightly at night or when we go out. Moreover, we have large solar gain when it's sunny so Comfort (and Comfort+ for that matter) mode is actually inhibited if a period of sunshine is expected (falls back to Eco).

The Comfort+ thing is my construct. Basically, it's for when the outside temperature is so low it's almost certain heating will be required. Because the UFH is slow to react the backoff and night and when we are out is disabled in this mode because it takes so long to cool/heat up it's just not worth doing this when very cold outside. However, because of the design of the house it is possible that even in this mode the house can be sufficiently warmed by the sun on clear days. In cases like this the heating is activated ahead of time (based on the inside forecast mentioned above) but on a reduced heat curve. This means when the IRC eventually decides there's a heat load there's already a decent amount of heat in the floor and it reacts much quicker than it otherwise would. If sunshine heats the house a lot then even the indoor 3 hours ahead forecast will be above the setpoint and the heating will not come on until that drops.

I have found that modulating the heat curve based on a scale block which is fed by the IRC load works well. Much better than having a fixed heat curve and just turning the heating on/off.

Anyhow, HTH and sorry to waffle a bit. To summarise, this is what works for us:

- Use a decent weather forecast input.

- Set climate modes based on external temperature forecasts.

- To cater for solar gain, inhibit/backoff heating based on sunshine present or forecast.

- Modulate heat/cooling curves based on IRC load.

Cheers,

Robin

[denver]

There are 2 IRC's, one labelled as v1, if you add v1 it wants to convert the block. Im try to get by without the v1 version (as Im told its the old one) but have to use the + & - in the app for the IRC to increase or decrease the temperature which kind of defeats the object. Is it worth going back to the older one for better control?

[Andras]

On Tuesday, April 2, 2019 at 9:35:55 PM UTC+2, Duncan wrote:

sounds fine - use a custom operating mode to set the IRCs to frost protection temperature (off)  and add to each IRC schedule, then you dont even need the 2 switches - this keeps the IRCs learnt behaviour for the next heating period

Thanks for the feedback. I am using the switches as I'm already on IRCv2 which doesn't let me choose custom values for modes (just the InUse, NotInUse and Off). I am planning to use IRCv2's for controlling cooling as well (starting/stopping AC), so Summer mode for me is essentially automatic cooling instead of automatic heating and frost protect.

 

On Wednesday, April 3, 2019 at 8:54:10 AM UTC+2, Rob_in wrote:

Hi,

What kind of heating system have you got? And what sort of monitoring/control?

Gas boiler coupled with UFH (living space) and radiators (bedrooms). Loxone controls zone valves and zone pumps and signals water temp through 0-10V to the boiler. Additional to the room control (IRCv2) in the living space, UFH can also be switched on by a logic (another IRC) that keeps the floor temp at 27C (measured using an average value reported by temp sensors in the floor concrete). I am also in the process of integrating the boiler with Loxone through an eBus interface.

Cooling is done by traditional A/C units. Loxone will be able to control A/C through KNX.

I am also inclined to replace my dumb on/off switches with some logic based on either forecast or average min/max values for the past n days.