Use hot water to heat the tank during power outage

[jda]

You need to do some math with only 40/50 gallons of water before you start to degrade. A traditional HWH is not good at trying to keep up with full-time demand. It looks like you might need about 20-22 gallons (my math is probably rusty and I have not had thermo since the 1990s) of that 120 degree water to move your tank up to 78 from 70 if you just add it without insulation loss, contact time and waste... and that is half of your HWH with no losses.

This seems like a losing equation like people who tried to use a fridge as a chiller with a bunch of coils in it. I don't see how you can heat 200 ish gallons (with sump) without this being recirculating.

Just get a generator... those super quiet ones like a Honda, or a knockoff, are barely noticeable by most people.

 

[ReefBeta]

You need to do some math with only 40/50 gallons of water before you start to degrade. A traditional HWH is not good at trying to keep up with full-time demand. It looks like you might need about 20-22 gallons (my math is probably rusty and I have not had thermo since the 1990s) of that 120 degree water to move your tank up to 78 from 70 if you just add it without insulation loss, contact time and waste... and that is half of your HWH with no losses.

This seems like a losing equation like people who tried to use a fridge as a chiller with a bunch of coils in it. I don't see how you can heat 200 ish gallons (with sump) without this being recirculating.

Just get a generator... those super quiet ones like a Honda, or a knockoff, are barely noticeable by most people.

Reminded me to do some math. To heat 220 gallon of water from 70 to 78 will need about 42 gallon of 120F water. So for lost and efficiency, let's say it's 50%, then it will use like 84 gallons of water. Not bad. And to produce that much hot water in 16 hours period is not big deal for the water heater. Even a hundred gallon water will be less than what it take to fill up my mixing station once with RO, not bad at all.