Posted by: @tim441

↑

It's interesting to note that it's taken me over 2 years to get to grips with optmised weather compensation... not sure I'm quite there even now!

Just 1 deg setback 9pm to 5am which I manually flick to 2 deg if mild.

Any other views?

so those points are the issue. No non-geek is going to tweak their WC curve on a daily basis based on a carefully written control process consuming data from the weather yesterday/ today/tomorrow, how much energy was used to keep the house warm, the flow temps, the COP, whether it "felt" comfortable or not, the price of electricity, other things I didn't think of, etc...

note that even the setback you mention isn't there as an automated thing on some HP's.

keen folk like us will tweak it more frequently initially , based on what we can measure and see / feel without too much grief, then revisit it less often as we get busy on other stuff / forget  / don't notice any issue.

OTOH, a really well written intelligent controller could do all that in automated fashion, every day, and therefore has the potential to get to the optimal state much more quickly and keep it that way. So I really support it as a concept.

In your case , you've already gone through 2 years tweaking so there is probably minimal gain in you getting something like this. however for a system that has no optimisation at all to start with, it seems like a really good way to get quickly towards a "quite well optimised" state. Obviously this assumes that the basics of of the physical implementation (generator and emitter sizing, flow rates and circulation design) are done right so the optimiser is not fighting against any negatives coming from those - which it sounds like was done right in your case.

@iancalderbank You can control any heat pump from home assistant by just controlling/faking/mimicking the outdoor air temperature sensor resistance, by artificially changing the weather.

@fazel indeed, all manner of things are possible if you have the time / energy / skills to "roll your own".  IMO the point under discussion here is whether Homely provides a suitable "canned solution" to Heat Pump optimisation, for the non-technical person who wants something thats plug and play, low startup effort, easy learning curve etc...

Posted by: @iancalderbank

↑

@fazel indeed, all manner of things are possible if you have the time / energy / skills to "roll your own".  IMO the point under discussion here is whether Homely provides a suitable "canned solution" to Heat Pump optimisation, for the non-technical person who wants something thats plug and play, low startup effort, easy learning curve etc...

[/quote

If my memory serves me well, I do believe that there was a discussion some time ago on the forum about the usefulness of Homely, with various concerns about its lack of transparency.

Let me first of all say that I am a firm believer in the use of auto control when possible, since I spent over 50 years as an Instrumentation and Control Systems Engineer. I worked on some very large industrial control systems containing thousands of input and output signals and numerous controllers, some of which I helped design. One thing that I learned very early is don't add complexity if it is not required.

Watching the Homely video it would appear to be the best thing since sliced bread, but it fails to answer various concerns that I would have.

How would it cope with cycling under milder weather conditions?

Does it actually use the heat pumps weather compensation curve or generate its own? Can it optimise the heat pumps WC curve?

How does it perform if the human operator specifies inefficient operating parameters?

What does Homely do if the heating system equipment has not been correctly installed and commissioned? Does it generate alarms or warnings?

The best control system in the World will not perform very well if the attached equipment or measurements supplied to it are sub-optimal.

 

I mentioned back in April that we were getting a Samsung HTQ 8kW ASHP fitted alongside a Homely controller and would report back with some data when I had it.

I now have some data, as per the image attached. The Homely controls the ASHP and during the time shown, I've switched from Homely not knowing my time of use tariff (Octopus Intelligent Go), to me telling it what my tariff by signing up to their 'Smart+' mode. You can see in the data that it has shifted the use of the ASHP to the cheap rate (i.e. from 31p/kWh to 7.5 p/kWh) and is preheating the house above the green set points.  Obviously the COP of the ASHP will be slightly lower (it usually falls around 3% for every 1 degree increase in flow temperature), but compared to moving from 31p/kWh to 7.5p/kWh, that's irrelevant.

Let me know if you have any questions!

Thanks,

Stuart