I think you will need an over-unity generator to make up for ejection losses.
Over-unity generators are mostly hoaxes or delusions. Maxwell's demon is a good thought experiment. Scientific American Magazine talked about reverse osmosis generating a pressure differential due to the difference in density of seawater versus freshwater for long pipe submerged vertically in the ocean with a membrane on the bottom. Very impractical but could work.
My head is hurting.
Mine, too! From brainstorms, mainly. ?
I think there is a guy on this site from White Horse who might be able to help you out with your question. It looks like you are using an ICF wall system which is what I used in my new home that is also passive solar. You might want to go to an 8" wall if you are going to pour the coil in place.
Thanx, my theoretical house is submerged in liquid nitrogen. My working 2-phase fluid in heat pump is also liquid nitrogen or something colder.