Buffer tank for geothermal DHW loop

djackman

Bought a house that came with an older but good working Waterfurnace water to air heat pump that has a built in DHW generator / desuperheater coil and circ pump. It is connected to a single 50gal electric water heater feeding off the cold water inlet and returning to bottom of tank.

I've read it's best to have a preheat tank before the main water heater for the geo DHW loop to operate on. I have an almost new 30 gal indirect water heater tank, would that make sense to use as the buffer?

DHW demand is low normally only 2 adults. Right now it's connected like Fig 11.

Hot_water_fan

Expensive but yeah that’ll work. You can configure it like figure 12? 

hot_rod

I think the desuperheater heat exchanger screws into the tank. The colder the pre-heat tank the more efficient that heat exchanger. So the bottom of the pre-heat tank will get you the best use of the desuperheater.

If there is a pump inside the HP you could pipe it to an indirect coil.