Hello, I am putting together a requirements list for the HVAC system on the new home I will be constructing this summer.  The core of the system will be a Nordic Hydronic DX GeoThermal Heat Pump unit that will provide domestic hot water to a pre-heat tank and either heated or chilled water for hydronic use.  The primary heating for the Winter will be radiant floor heating on all floors, however with hot humid summers and an airtight home, I will still require ducting for A/C and HRV purposes.

Where I'm having a little trouble nailing down my requirements is on the cooling side.  I have an idea to use a LifeBreath Clean Air Furnace that would use the hydronic output of the heat pump through it's hydronic heat exchanger to provide supplementary heat (as required) in the Winter.  It would also provide air ventilation and fresh air exchange.  For the summer, I'm wondering if it will be able to provide enough cooling and condensation to provide comfortable living.

This is the area I'm a bit confused.  The manual for hte hydronic heat pump clearly shows a setup configuration where you would heat through radiant in the Winter and then use an Air Handler unit for supplemental heat and summer cooling.  The heat pump in cooling mode provides chilled water at around 46 degrees.  Typically for cooling with the Clean Air Furnace you would use a direct expansion cooling coil (refridgerant evaporator/compressor loop), but this of course would be redundant in my case.

Any help/comments on this would be fantastic, I'm really confused!

There are coils intended to cool air using chilled water. You may find that the same coil used to provide supplemental heat by transferring heat from warm water to air will also do for chilled water - just be sure it has a mechanism to collect and drain condensate.

Thanks for this.  The heat pump manual refers to a "Fan Coil Unit for Heating and/or Cooling" that uses hot or cold water supply, so I'm assuming this is feasible.  Looking around though I can't find any specific products, do you have any suggestions?

Honestly, no, but it isn't rocket science. Coil should be sized for your expected cooling load, water temps and air flows.

Anyone selling hydronic heatpump / chiller ought to be able to assist you with brand / model suitable for your application.

First Company has it, but there will be about 6-12 weeks lead time needed.

My system is set up exactly as you describe. 2/3 of the house is heated by hydronic in floor and the remainder is heated with forced warm air. A single water to water heat pump supplies both. The Air Handler is sized to provide all of the forced air cooling in summer and then for heating the supply ducts that feed the hydronic space are closed off w/ dampers. The AH is a Magic-Aire unit. I bought it after giving up on the long lead time from FirstCo.
The only drawback is I bought a 3-speed fan motor which doesn't have enough turn down in winter. I'm tempted to replace it w/ a variable speed. Other than that it has worked to my satisfaction.

I'm looking for ductless wall units myself.
Thoughts?
J

Good luck on that one, Joe.

One guy sold that idea to a home builder on a huge house. The HVAC guy wanted to get the duct installed under slab before they poured, but this other guy, a consultant, told the builder they could just run supply and return water lines for ductless wall units.

After the fact, he was found with egg on his face. He finally found something manufactured in Germany. On inquiry, the HVAC guy found out that this product is not available in the US. What a mess that turned out to be. Now they're using city multi from mitsi for the cooling, but still are using geo for the radiant.

Just to add to the last, the problem was that he wanted chilled water cooling units, not just heating...