At the moment I have a separate Python script to drive the heatpump which I use it to drive the manufacturers web app. The folks on this forum are much better informed in implementing control hardware than me.
Emoncms is acting as a central point for data from the solar panels, weather station and heat pump so the control alogrithm can get what it wants.
When we get a battery and an agile tariff I may move to the Demand Shaper plugin for Emoncms.
You might be interested in these experiments I did…
Notably, we don’t heat for when the showers are planned because there are four people in the house and showers are very random. In fact sometimes we shower when it’s a good time for the heat pump. For example we’ll shower at 13:00 when the morning sun has heated the tank and we’re creating “space” for the afternoon sun to heat the tank. Also, our tank doesn’t lose much heat so we’re free to leave it full of water.
Yep Brian, that’s been a key part of our setup too. The residents know they can just tell it what to do whenever they like if the clever stuff isn’t working for them. That makes them much more willing to let the computer take control most of the time. It’s rare they feel the need to intervene. My control algorithms have gating unit tests which stops them going live if they are going to misbehave.
It sounds crazy, but I can understand why you’d do that. We found we weren’t emitting enough heat with a room delta that low so the pump would switch off because the return was coming back too warm.
We think of the radiators as “a big warm dog lay in the corner” rather than “a furnace” so if they are only running at 28 Celsius that’s fine.
What will it take to make you very happy?
It’s not as mad as it sounds. I took the defaults on our system in October and November and only took computer control at the end of November when I had something interesting to work on and some evidence that the defaults we’re working for me.
That bumped us up from the red line to the blue line:
It was warm enough in October that it would have been OK to have been playing with the control then and people wouldn’t have noticed much. You probably want to get the hardware in place by then though.
Good luck.
David
Fair point on not timing DHW for showers. Ours is ‘only’ a 200litre cylinder, and seems to be losing about 80W at ~45degC, but that gives us about 24hrs of warm water from a DHW run so that should be enough to play with.
I keep meaning to ask - how is your ‘effective’ outside temp calculated/detected? (I assume it includes some function of solar gain/extra infiltration losses on windy days etc?)
Yes, mainly optimizing advice tbh and how you’ve managed to extract that data to monitor the cycling. We’ve got the 17kw aerona 3, ground floor ufh and rads upstairs. We did have 9 seperate ufh zones on the ground floor, but I decided to cut that down to 3 by re-configuring the manifold wiring boxes to disconnect 6 stats and then connect the three remaining stats to get three fairly large zones. I think the heat pump is cycling much less as it now has more volume to heat up each time one of three stats kicks in. We have the hot water cylinder with integrated 50litre buffer/volumizer - this has been configured to use the 50l as a volumizer on the return flow to the ashp. I can’t quite get the 8degree delta T that the grant manual asks for - when ufh and rads are on, i’ d guess that there’s a royal mix of thermodynamics going on! I’m pretty sure that i can probably tweak the ufh manifold to get the 8degC difference, but not sure what to do with the rads upstairs. It’s a new build so the rads upstairs come in here and there, so we’re not heavily reliant on the upstairs being optimised tbh.
unfortunately i didn’t do the research to challenge our plumber beforehand. I normally do my research…