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Hi all, We are looking for opinions and advice on the systems we have currently specified for our build. It’s a near-passivhaus build, with MBC timber frame on an insulated raft foundation. Our predicted SAP rating is 102. The Primary fuel will be electric, there is no gas in the village, and we don’t intend to install LPG or Oil. We plan on having a large solar array (just waiting to DNO approval at the moment) and Tesla Powerwall – using the Octopus Tesla Electricity tariff, so power diverters and smart energy management are off the cards. We are looking at having a Sunamp Heat battery, in place of a hot water cylinder, and heating the house will be Ground floor UFH, and potentially using the MVHR air. We would like to run the ASHP in reverse in summer to cool the ground floor slab and the MVHR – but would still need to run it forwards to charge the heat battery. The Sunamp would be the HP version, which has primary input of (High Temperature) ASHP, and a backup option of mains electricity. This suggests 2 possibly options for Hot water in summer: 1) Run the ASHP in Heating mode when necessary to charge the Sunamp – and disconnect the UFH and MVHR art this point 2) Always run the ASHP in cooling mode when actively cooling, and charge the Sunamp from electricity (surplus from the solar in summer). Sunamp specify ASHPs to work with the heat battery, one being the Valiant aroTherm which is reversible. We wonder if anyone has done this sort of configuration and can offer advice on how they achieved it / information on how it has performed. Is there a valve / manifold product available that could handle isolating the output of the ASHP from the Sunamp or the Heating elements depending on which mode is being used on each? Our main concern at the moment is that we like a cool bedroom (17 – 18 degrees) and want to make sure we can achieve this year round with the systems we install. Here is a simple diagram of the system we are trying to describe with this post.

Not much depth to it, but some rare coverage of the issue of storing electricity. BBC website article on power storage