Wil

@NickfromwalesThank you, I’ll insist he changes it.

Yep, it certainly makes the meter spin when it all runs together. Ah yes, only one can ever do the DHW, currently the 18. I would aim to drop the 26 altogether in the future. In the CE diagram 18 is on the left and 26 on the right. The intent of the proposed was to allow them to run in parallel for heating and one for DHW but that’s not what is shows! I’ve read in the other threads about removing buffers and using volume of system (my house is plenty cold enough there’s valves open). But specifically at the moment is is the pumped UFH system the correct approach? Can I simplify as per JohnMo’s example or is the current setup optimal in terms of feed.

@JohnMoThey’ve been installed per top scribble for 3 years. I appreciate the ridiculous oversizing but I have another project this 26unit will move to once I finish the upgrades to the main house and can prove just the 18 copes. this is the ASHP setup as per CE:

I’ve got an 18 and a 26 in a weird parallel situation (blame Cool Energy for the upsell!) I’m hoping to get to just the 18, but it does defrost a lot and the 26 helps carry through those moments.

@Nickfromwales see scribbles below. Current above, planned below. The idea is I could eventually drop the oil and the 26kW ASHP but they’re there anyway so might as well use them.

A pretty terrible scribble, give me a few mins to tidy it up!

@Nickfromwales Thank you. If it was just an ASHP, would it be acceptable to have no control? Is there any point in the 4 port and pump? Why not just run it as a big radiator?

First of all- HOLY THREAD RESSURECTION! But hoping @Nickfromwales might be able to confirm if the advice above has been superseded- The builder’s plumber turned up, saw an ASHP and looked no further. He then supplied a manifold with a pump and no mixing valve- just some sort of fixed 4 way and a pump. I have the ability to run the oil boiler in to the heating circuit and the Buffer tank has an immersion in it- so I would consider a TMV still required. He just keeps saying ‘it’s fine for an ASHP’ - is it ever fine to not have a TMV?

Ah yes, I missed the sqft, not sqm. Still 512m2 is pretty damn impressive! Unless you can get a large scale turbine PV will outperform it- I have a 1kWp unit and on its best day ever it managed 2kWh of generation often the daily is nothing or a few tens of Wh. The 5kWp PV regularly outputs 20-25kWh peaking at 35kWh in a day. The turbine isn’t ideally sited, but you’d need planning permission for a full tower and a much bigger unit to get a decent output. I’d have to say the PV looked better at that point.

Can I come see it, I’m near Titchmarsh and being nosy about a 9000m2 Barn conversion? 🙂 Sounds like there’s lots to consider with GSHP and secondary circuit. Do you have an PV or anything you can divert into the newly wired immersion?

TBF the biggest issue with the Powerwalls is that they aren’t a UPS and can allow a brownout as the power drops which means a lot of stuff switches off. Once they get hold of the load they can output 10kWp (14 for short duration) and keep the basic inverter online so the power keeps running. The power drop almost always gives a big enough spike to take out my main 100mA RCD though, so they can’t return to grid until I reset it. I’m very jealous of some of the consumption figures- I imported 20.1MWh last year…

Impressive Mike! My solar only produced 785kWh (unshaded SSW array in the Midlands) in May! £150 back would be a pretty nice payday! My installer has now enabled export on the batteries so I can dump what’s left in them at the end of the day at 15p and then immediately charge them back up at 7.5p. Will see how that goes for a bit before deciding how much I want to fully cycle them every day.

I’m assuming that I would have used the import energy anyway and been paying for it. So every penny in export is effectively ‘gain’ from my previous situation. It’s probably too simplistic as the solar charging the battery would have meant less charging the following night. Either way- today I’m at 25.4kWh import and 20.5kWh export so figure I’m up for the day. The £250 is also a LOT less than I would have paid for an MCS install- am I allowed to offset that cost?

Turns out by changing the tariff in my Tesla App, it’s sorted itself out and is now exporting all the solar and just slowly discharging the battery to cover the house. Haven’t seen what it does when the house loads look like they’re going to exceed the battery capacity during the day but got 13kWh of export yesterday vs 34.3kWh of off peak input (house/car/battery charge). Once it settles down I should be able to see what my break even on the £250 is going to be! 1667kWh of export either way.

I can’t export my battery sadly as it was set up prior to any export agreement. I let the HW charge from the ASHP whenever it needs but have been dumping solar into it until recently. You make a good point though- I could export the batteries to 30% (in case the HPs kick in during hte day) and only export the solar.

I’ll answer my own question- i got an email a day later saying i was now on octopus outgoing… now have to adjust my automations to not consume every last drop. 15p/export vs my night rate of 7.5p means worthwhile exporting once the battery and the hot water are complete.

Sorry to thread resurrect- but for you CoolEnergy owners- any way of getting the COP (or even just the actual heat output) out of the Controller? I have the electrical measured elsewhere but would love to know what COP I’m getting. Just not love it enough to pay £1000 to emonpi for their meter…

Yes it’s £150 back if they reject you, so only £100 lost, but just wondering what hoops I need to go through having had all the paperwork submitted to them already.

I have batteries (although set not to export due to the 3.68kW per phase limit) and on Octopus Go so 7p overnight 11.30 to 5.30am and 23p the rest of the time. Getting a blended rate of approx 16p so far this year. in winter with the HPs I rarely get past lunchtime before the batteries are flat. Let alone 4-7 to export what’s left. I charge EV, battery and dishwashers/ washing machines overnight to maximise night use and can avoid 90% of daytime usage which means I dump solar into hot water tank and anything else. I currently export almost nothing but I could heat the HW to 65 instead of maxing out the immersion and actually concentrate on some export.

Yep I do that already, but I have the capability to add significantly more PV (and DNO agreement to export 11.68kW) so I could be making money back on the days when I’ve filled the hot water tank, batteries and car. I can get 35kWh on a decent day with my currently 5kWp array. I have a functional smart meter so hoping for at least 15p/kWh. I already have the export MPAN from the DNO, just need octopus to accept it! I’m sure I read of others here who had used the non-MCS route?

Apologies for a new topic on this - I did search but couldn’t find previous topics- I’m trying to sign up for Octopus’ non-MCS export route. I’ve provided my DNO letter and Building Reg cert covering the install. They now want the £250 ‘with no guarantees’. Anyone that’s been through it know what happens next? Are there any further loopholes/ reasons for them to reject? TIA!

Looks significantly better than my roof! Fortunately I’m married to the SE and a quick site meeting was enough to decide to crack on without full replacement. I’d agree with the above- architect notes that existing load on roof being reduced and roof improved with breatheable materials.

I have a similar set up done slightly differently and nowhere near as neat. One question is- why separate the boiler and ASHP? Do they need to be hydraulically separate?

Generally it’s to keep all the potentially dodgy IOT devices and cameras in a network that can be tightly controlled and prevented from talking to the rest of the world. Then you can initiate traffic from your ‘main’ LAN into the IOT network to get the info but the stuff in the box can’t ‘phone home’. Lots of Shelly/ ESP devices used to be (are?) 2.4GHz only and didn’t play nicely on a mixed 2.4/5Ghz network.

You can choose the VLAN of each port on those individually? I keep my iot and camera network separate to the rest and have 3 of these in the network (mostly to save me getting up and pulling another cable 🙂 )