I have a modest set of solar panels on an entirely ordinary house in suburban London. On average they generate about 3,800kWh per year. We also use about 3,800kWh of electricity each year. Obviously, we can't use all the power produced over summer and we need to buy power in winter. So here's my question: How big a battery would we need in order to be completely self-sufficient? Background …
I did math for Toronto, Canada. 2000l of hot water was enough (2m3). Winters here have gotten cloudier from great lakes warming. Instead of more water as a buffer, dirt is much more space efficient, and just needs the hot water routed through it to get heat transfer.
The volume looks more like a room than a box, unless you can somehow make it molten that is
If hydronic heating system was already being directed towards outer walls instead of straight up from water storage, then a tall “hot dirt” storage, and dual cold water mixing valves (pre and post dirt flow) next to each other, it’s less in additional storage costs per heat unit than water, though it does use more electricity to input heat compared to heat pump.
No need for temperatures higher than melting/softening point of copper to get useful heat storage for a home. Just water can be enough if you have the room.
I did math for Toronto, Canada. 2000l of hot water was enough (2m3). Winters here have gotten cloudier from great lakes warming. Instead of more water as a buffer, dirt is much more space efficient, and just needs the hot water routed through it to get heat transfer.
If hydronic heating system was already being directed towards outer walls instead of straight up from water storage, then a tall “hot dirt” storage, and dual cold water mixing valves (pre and post dirt flow) next to each other, it’s less in additional storage costs per heat unit than water, though it does use more electricity to input heat compared to heat pump.
No need for temperatures higher than melting/softening point of copper to get useful heat storage for a home. Just water can be enough if you have the room.