I have a problem that I thought others might find interesting. I also thought someone might have an idea on how to proceed?

I was in the role of architect when we worked with a mechanical contractor, builder, high velocity system company and a DX GSHP company to install a very nice green building mechanical system in a custom home. I asked the mechanical contractor to match the high velocity system or report that it could not be done, but was told it could be. I had assumed he was in touch with the high velocity company and the DX GSHP company.

The system is now installed and is running at about 1/2 capacity, I think because our 5 ton DX GSHP is matched to a high velocity system rated not at 400 CFM/ton, but rather 200+CFM/ton. I need to figure out if this can be fixed, or if not, what to do...

The rest of the system includes having the DX GSHP also connected to a refrigerant-water heat exchanger that is connected to a large DHW tank. There is then a plate heat exchanger that services a hydronic heating tank connected to the main DHW tank for the radiant heating.

So I have many ideas, but most are way outside the box. Another small blower in series? Another refrigerant coil in the blower, but piped with refrigerant in parallel? Use the refrigerant-water exchanger to heat and cool the hydronic tank and replace the refrigerant coil in the air handler with a water coil, or water coils?

If anyone has been here before, I'd love a hint.

Glynn Bebee
Ithaca, NY