I am planning to add a 12kW Vaillant Arotherm Plus to my setup which has a 5k Multiplus II, 6.9kW of PV and 10.65 kWh of Pylons.
The HP has a max starting and running draw of 23.3A. The ideal scenario is to power it as follows:
- from Economy 7 cheap rate at night
- from Solar PV during the day
- from the Victron battery system during the evening
I hope to get as close as I can to this using the following control strategy
- Scheduled Charge to 100% from 2300 - 0000 and 0100 - 0700 (these bizarrely are the E7 times in my area of S Devon).
From 2300 - 0400 (say) the HP will be on night setback to reduce noise.
From 0400 - 0530 it will be on a slightly high setting to charge up the floor slab at cheap rate
From 0530 - 0700 it will charge a 210 litre thermal store to 55C and heat the hot water - During the day and early evening (0700 - say 2000) use Scheduled Charge set to 10% to prevent the HP discharging the battery. This will keep it fully charged and so available in case of a power cut. Any PV generation will reduce peak rate consumption from the grid. If there is prolonged fine, cold weather I can reduce the overnight target to less than 100% to leave room for surplus PV.
- Late evening (2000 - 2300) terminate the scheduled charge to allow the HP to run down the battery. Use the thermal store to heat the radiators in the bedrooms. Adjust the start time of 2000 so the battery is just out of useful charge when the cheap rate starts again at 2300. Possibly I could automate this last step with Node Red, all the rest can be done with standard ESS settings.
I would be grateful if anyone can suggest improvements or alternatives to the above. Particularly @Jason - UK who IIRC has a similar setup with a Mitsi Ecodan.
Would the new predictive ESS help with all this or is it an irrelevance?
TIA