CSV and PRV at the same time?

[project_x]

I have an open loop geothermal system that utilizes my well water supply for both domestic water (ideally, high pressure, low flow) and geothermal (ideally, low pressure, high flow).

My well supplies 20gpm @ 50psi and I have been using a CSV for the last 10+ years.
My well is at 80ft, my static level is 10ft and the draw down is negligible.

My system works, and has been working for 10+ years.
At some point, I would like to install a much smaller pump and set the pressure to 15psi to supply the geothermal system with high flow and low pressure water. Then utilize a booster and raise the house pressure to something usable. But that is for another day.

In the short term, can I put a PRV after the pressure tank, on the geothermal line and reduce the pressure to 20psi....will there be any benefit or issue?....I would like to reduce the pressure on the furnace's water coil


Also for proof of concept, what would happen if I put a 20psi csv in line with the 50 psi csv that is currently in the well and changed the pressure switch to one that runs at 20psi? What would happen?
I would love to be able to plumb some by passes in to test the low pressure, high flow, and booster pump....without pulling the 50psi CSV and current well pump.


Thanks

[Cary Austin]

A pressure reducer would only lower the pressure on the furnace water coil, which I don't see as much of a benefit.  But just to test and see if the heat pump will work at 20 PSI would be OK, but I can tell you it will work fine. 

Reducing the size of well pump to work at 20 PSI and/or finding a well pump with a good drop in horsepower will save energy with the heat pump.  Sometimes just finding a pump with a good drop in horsepower is enough.  If the well pump has a good drop in horsepower when the flow is restricted, there might not be much of a savings to use a smaller well pump and work at 20 PSI.

What horsepower and model number is the well pump?  And how many GPM's does the heat pump use?

[project_x]

It is a 3/4 hp, I believe Myers, but have to check.

It draws about 4.3A while running.

The furnace uses roughly 10-12 gpm

[Cary Austin]

A 3/4HP is already a fairly small pump.  And using 10-12 GPM for the heat pump will probably use all the water that 3/4HP can pump.  1/2HP is the smallest well pump they make.  I don't think it will be worth it to switch from a 3/4 to a 1/2HP.  Now if you had a 2HP in the well the two pump system with the lower well pump pressure can save a lot of energy.  But 1/4HP difference isn't going to amount to much saving.