I am a new user to the forums but have been reading and appreciating the education for quite some time. We are in the process of building on a large parcel of land with a planned open loop water furnace system encompassing 3 heat pumps (3ton, 4 ton, 3 ton) and an envision system to provide heating, cooling, and hot water for the 2 homes we are building on the property. I've begun to consider that there will be a relatively large volume runoff from this open loop system as well as the fact that we have a 100-150 foot drop off in the 500' behind our house. Is there any precedent for involving a micro hydroelectric system to capture the energy being 'poured away' in this scenario or is the volume still too small to capture significant energy? I've searched the resources I'm familiar with and can't find any discussion of combining these systems. Thanks for your thoughts.

The cost v benefit would not be that difficult to calculate. Assuming 10 tons will move a couple million gallons of water each year, you could shop the generator side and see how many kw's you might produce with that.

Bear in mind however that geo needs GPM not necessarily pressure so you would want a generator with like parameters.

The discharge water might not be poured away, but can lower pumping energy.

How high will you have to lift the water to your heat pumps? If you run the discharge pipe down the hill that 100'-150' of drop you could get some siphon action going which would significantly reduce the power to pump the water up in the first place. If your water table is high enough, you might could get by with a pure siphon arrangement if you put the electric shut-off valve at the end of the discharge pipe at the low point in the piping arrangement.

That's an interesting thought . I'll have a variable speed pump but I'd have to look into it to see if it could allow the siphon to produce most of the flow and the well pump add as needed? It would seem to me the the siphon discussion and the addition of a hydroelectric generator at the bottom of the hill aren't mutually exclusive additions to the project I'm not sure where the water table is yet…we haven't gotten to the point of well digging.