How much increased well pump usage with Geo?

Wow. Makes me want to buy a mule and hook him up to one of those "turnstyle" thingies instead of using an electric pump!

If I'm reading you correctly, that "3/4 hp" pump is really a 400W pump and a 1000W heater? yowsa!

 

three contrasting 1/2 HP pumps

1) Cheap noisy Flotec transfer pump - consumes about 1000 Watts (per my Kill-a-Watt) and moves 4-5 GPM through an open garden hose

2) Nearly silent Goulds septic dose tank pump - consumes around 600 Watts (Per Kill-A-Watt) and moves about 20-30 GPM to my drain field through 200' of 2" PVC, about 15' uphill.

3) My well pump is somewhere in the middle - cheap and noisy, but good for about 10+ GPM raised 30 psi.

 

Assuming your well pump is satisfying the heat pump water demand and you have no additional demand this sounds to be the perfect size pump. It is not cycling, and that is wonderful. Also I'm not so sure bumping the HP would be the most efficient way to get more water, you want to check the pump curves. I have 5.5 tons of capacity which I'm realizing could be met with a 1/2 HP pump (but I have a 3/4)

 

Question

I have a 18,000 - 23,000 geo thermal open loop heat pump. Just my wife and myself in the household at present. Recommended water flows would be between 3 - 6 gallons per minute. Present well motor flow is rated 12 gallons per minute, new. Our 1/2 hp 240 volt single phase well motor works ok, draws 8 amps, though it runs constantly at present on 66% capacity or 100% capacity on winter regulated flows. The well is in its 10th year, so I know it will go out in the next 36 months.

Can I improve my setup? Should I go to a 3/4 hp motor? What are my options?

 

If your happy with your present water delivery system, when the time comes I would replace with the same type of unit you have. Happiness with your water system equals when the heat pumps are at their maximum usage and the pump is running constantly, is there enough pressure and volume left for your wife and you to do the things you want to do? In other words do you not take a shower because the geo is on? If the answer is "we are happy now" I would not change anything. The KISS principle takes precedance. If you are not happy then upsizing the pump may be an option, but cycling may occur when geo is not running at full capacity. There really is no perfect solution. The best way to address variable flow demands with constant pressure is by using an variable speed pump that will not cycle on and off as flow demand usage changes. However they are pricey up front and the ROI must be considered vs. the lower cost of traditional equipment that you will kill by cycling it.
Hope this helps
Eric