I was speaking with a local geothermal installer on Friday,
and the topic of solar came up.

They have a lot of experience with solar thermal hot water.

This started me thinking, could a "Ground Source" Heat Pump
also be used with a Solar thermal water heater?

(If the question seems to you like I don't get it, it's because
I am not typing it right.   I understand what the vendors are
claiming is possible, and I am wondering if you can mix.)

(A word on my background: I am a hospital systems integrator;
I make incompatible computer systems talk to each other.
I'm basically not allowed to say "Can't do it" :-)


To clarify my question -
a GSHP takes most of the heat out of the water, sends water
down into the earth to get some more heat, then repeats that.
Why can't the cycle include going up to pick up the heat?
(A holding tank could be used as well;  I haven't reached "design" stage.)

Thanks
Seth

They make a lot of sense together, in europe solar hot water is used quite frequently to heat the DHW in the shoulder season. The judgement is still out to use solar heat to help recharge the loops in heat dominated climate. It would make a lot of sense in the fall, to reject heat into the ground, especially if that heat comes at almost no operating cost. No so much in the spring, since you want the loops to be cold for the start of the A/C season.

I don't see any reason why a closed loop couldn't incorporate a solar holding tank. Some controls would be needed to keep from returning water to the loop warmer than ground temperature, and the solar tank would need to be bypassed in summer.

A better approach might be to isolate the solar tank, use it for DHW and hydronic (radiant or coil in ductwork) and use geo to make up any shortfall. ROI, operating, and maintenance costs should be addressed for all alternatives.

We have been trying to persuade a local builder to add geosystems to their houses.

They have been installing the Solar Systems shown in the attachements.

We have yet to convince them that Geo would be a better deal.  Plus we could do it for less than what they are spending on the solar system.

The photo shows the solar panels on homes one week after a snow storm.  Snow still covers most of the panels,  so I doubt there is much benefit.