Hot Water Storage Calculations

Use Hot Water Calculator.

It takes 61 kWhr to heat up 250 gallons from 90 to 190F.

Senville Aura puts out 24000 BTU or 7kW. This would be 3 hours of heating with 20kW of solar, but given that winter sun may be sparse, this may be much less in practice.

If running from solar heat, it would be wise to include a large solar panel system - 20kW and up. And minimize the battery storage in an off-grid scenario. Ideally, we have great insulation value with lots of thermal mass, so the walls themselves are providing heat storage. And, using the thermal mass around the exchange medium.