Posted by: @tim441

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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

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@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...

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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

@iancalderbank I realise this is an old thread but in case anyone is still reading it: I have had Homely in now for about 18 months. I have not applied full geekiness to my heat pump (scared to) so I have just used Homely (for about 18 months). I would say it works pretty well. If I compare it in dumb mode so it runs heat pump required and off when not required Vs smart mode where it does it's own thing with the heat pump in order to reach target temperatures as economically as possible, then the fuel cost is about the same but in smart mode the house is nearly up to target temperatures 24 hours per day. Anyone have any specific question about Homely, I am happy to reply.

@mikeavison One observation I would like to mention: In the fully smart setting (that is using Smart+ and set to Agile from OE), I find that Homely would appear to have a phobia about not going below the set temperature. I mentioned to their techie staff that I find deviations of plus 0.6 degrees C but it never drops below the set temperature at any time. Their technical staff tell me that their aim is 0.5 degrees C deviation. The ‘smartness’ sometimes tells the pump to heat up above this limit by perhaps another 0.5 degrees C in anticipation of higher tariff or dropping temperature. Overall, I find Homely to be a good obedient servant though! Regards, Toodles.

@toodles yes, I think you are talking about space heating, I agree. I presume this is because when it's working out of target times, it's ticking over with a small dT so it increases efficiency by running low and long. However hot water is handled quite differently, it pretty well only runs in the on times. So if someone has used it all you have to wait till the next scheduled on time or press "boost". My wife had a few cold showers before we realized that!

@mikeavison Oh Dear! I hope your name wasn’t too brown and sticky! 😃Our hot water is handled separately by a Sunamp Thermino eP210; this is because we don’t have a suitable space for a tank without major work to accommodate one. Regards, Toodles.

Has anybody installed/use a Homely smart controller, are they as good as they make out. If you believe all you read it cuts out all the guess work for setting the weather compensation curve and increases efficiency of the heat pump by up to 25%

@potatoman Yes, we have a Homely smart controller attached to our Daikin monobloc 8 kW ASHP. Fitted last autumn as soon as the integration for Daikin was available. We are chilly mortals and for medical reasons, we like to heat the whole house to 22.5 degrees C. I find that the COP is at worst, about 3.5 or so and in milder conditions 4.5 and occasionally, even 5.4. The homely  NEVER allows the temperature to drop below the setting though it does tend to rise 0.6 - 0.7 degrees above in the afternoons. This may be solar gain as the living room has the temperature sensor and the room faces north east but the solar gain is at the other side of the house. Homely will anticipate Agile advantageous HH’s and monitor the weather and generally anticipate changing conditions very pro-actively.. Homely just gets on with the job really! Regards, Toodles.

@toodles Hi, thanks for your reply, is the temperature 22.5 degrees C at night as well as day or do you have any set back temperature at night, and is your circulating pump on 24/7