Harvest hot water heatpump system

[begreen]

I just saw this mentioned by a homeowner on Reddit. It appears to be California only. Does anyone know much about this system?

Harvest Smart Thermal Battery. The Smartest HVAC on Earth

Heat your home, not your home planet. Reduce carbon emissions from home heating up to 90% compared to gas furnaces and save up to 40% on home energy costs.

www.harvest-thermal.com

 

[woodgeek]

Meh. It uses a HW thermal battery to store BTUs pumped during the day (cheap kWh) for use at night (expensive kWh). The same battery is your HW tank.

Seems sensible enough, and CA appropriate.

If you heat the HW too much, you get COP losses, so the swing is likely small. The Air handler has a hydronic coil, so low service water temsp are not much of a problem. Say you swing from 100*F to 140°F, and the tank is 100 gallons. 800 lbs* 40°F = 32,000 BTUs.

My house needs about 10x that much overnight in winter, and I don't have TOU pricing. So useless for me.

For a well insulated CA house with TOU and cheap (solar) daytime rates... sure. But if you're only using 32 kBTUs at night, you are using <2 MMBTU per month, and your energy bill for a conventional system is pretty cheap already.

Meh.