"Rob Dekker" writes:


PEX comes in various ratings, but typically can handle close-to-boiling
water under pressure easily.

My system is a closed-loop system driven from the water heater, and
can't get any hotter than 130 F and low pressure (12 psi PT relief
valve on the loop). But even if all safety measures would fail, the my
(cheap) PEX can handle 100 psi at 180 F, so I feel pretty secure that
something else will blow out first.

I'm talking degradation, not sudden pressure failures...I'll let you find
out if it's true...your tubing is easy to replace.

But I didn't lay the floor, just designed the GSHP controls and
installed them.

Cool. I did not go that far. How much piping went into the ground ? ?
How deep did you have to go What were the economics calculations of ?
such a ground-heat system versus other heat sources What was the water ?
temperature requirement for the floor heating system ? How did that ?
affect your GSHP specs I wonder how that system looks like. Have any ?
pics ?

Well, it was that or propane; and the 10 years since have proven
the wells a wise choice.. but it was lots of capital. [3 wells,
~250 ft deep.]

I don't have any pictures. I think there are 12 floor zones and
6 FCU's used for AC as well.

I currently use my water heater as a heat source, but are now planning
to hook that up to DHW solar panels to get some heat from the sun.

We installed a spare 40 gal in case of a GSHP failure or lengthy power
outage. My SWAG showed it would keep the house about freezing. It's never
been used; when occupied & fed, the 2 wood stoves can drive you out onto the
porch in a blizzard, if fueled with pine.

The desuperheater feeds the domestic HW tempering tank.

The idea was you can disconnect that one loop and use the other{s}.

OK. Makes sense, especially in emergency situations. But often a leak
did already do water damage to the flooring before we find it out, so I
would think that it requires fixing either way.

Hard to damage concrete with a little water.


I think that's called a insulated sandwich slab-on-slab. Great system !

Over existing slab, put 1 inch (or more) insulation, lay out rebar and
PEX tubes, and poor a couple of inches of concrete over it for the
new floor.

This IS slab; installed at construction. Yes, it is slow response.

Downsides are that the system is pretty thick (4 inch minimum) and that
water temps need to be relatively high (140 F and up).

No way. I have to think but I recall our upper limit is 30C. With
a GSHP, it costs exponentially more to raise the loop temp.


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