Kevin, Thanks for the URL. Water furnace was on my list of possibles. I'm not as far along as I wish I were in engineering the HVAC. I don't have the practical experience or feel for cost so I can design a while then find out that the idea sucks or is too dificult to do in practice or is just too costly and won't have a payback within the installed life time of the equipment.

I still have a few ideas to check out. I will be pricing an essentially duct free system with distributed air handlers instead of a centralized system with oodles of ducts to breed mold, fungus, mites and other life forms best not raised in captivity.

My idea is to have the output side of the geo-thermal unit heat or cool a quantity of water which in the case of heating the home can be used for an in-floor hydronic system, or distributed baseboard,or whatever will heat the home using circulalted hot water. One of the units I saw that I like is a small fan coil unit designed to take circulated hot water. It is made to mount under cabinets in the toe kick space where it pulls in cool floor level air and puts out warm air. I talked with the manufacturer and for a small non-recuring engineering fee they will add a condensate drain tube and do a powder coat to ensure corrosion resistance. If you circulate chilled water through it and turn its fan on you get cooled air. So it lends itself to a zoned/distributed system and can heat and cool. OF course it can be mounted in the ceiling, wall, or wherever. It does not automatically elliminate in-floor hydronic as they can be compatibly used together. As you know the big problem with hydronic heat is the lack of hydronic cooling and the requirement to have much system duplication to get cooling (two complete circullation systems, one for water and one for air).

Any serious atempt to cool with surface hydronics (ceilings are better for cooling than floors) runs into condensation problems. If surface temps stay enough above the dew point to avoid having a mold farm form, then you don't get enough cooling, at least not where there is any significant relative humidity. Usually, practical dehumidification calls for circulating significant quantities of air.

One scheme I considered was a large metal sculpture and or an ice wall. Consider a large metal sculpture in the great room backed by a wall with lots of artistically shaped and positioned metal plates. There would be a shallow "pool" around the drip zone of the sculpture/wall area. The sculpture and wall plates are the evaporator heatsink for the AC system. When it cycles on, condensation forms on the wall where if forms many interesting water falls as well as dew on the sculpture and drips into the tiled pool to drain away. As the metal chills down below the freezing point, icecycles, frost and ice crystals form in changing patterns until the ice coating gets too thick and the efficiency drops and the unit goes into "defrost cycle" just long enough to weaken/shed most of the ice coating and then revert to cooling cycle where different shaped ice "sculptures" form depending on the random remnants of the previous cycle. This repeats as long as cooling/dehumidification is required. I still like the concept but havent got the inclination to spend the time, effort, and $ to prototype it nor the extra space in the great room to install it. Even if it was way undersized to do a significant job on its own, I think it would be a fascinating object de art and or conversation poiece.

Thanks again for the user report and URL for Water Furnace. I will be contacting them. I am leaning toward the Freon in the ground system as it is less expensive, takes less trenching, doesn't require water pumps for the external circuit and uses one less heat exchanger. If you haven't seen them, they are not particularly special. They just let the compressor circulate freon in the ground loop and elliminate the freon to water heat exchanger, pumps, and associated controlls. Otherwise they work the same except for higher efficiency and lower initial and maintenance costs.

Patrick