All systems go!

Wednesday August 25th we had power-on for the GSHP system in cooling mode. The good news is that it appears to work. They finished the duct work, control and thermostat wiring, setting the condensate pumps and running condensate drains for my water heater and GSHP.  We even tried out the desuperheater and it appeared to generate hot water.

In the picture on the right, you can see the 5 "wet" connections for the GSHP. The two copper pipes are for the desuperheater -- to heat the hot water in the white holding tank. The white pipe is for the condensation. You can see a small condensation pump tucked in behind the black insulated pipes. The black insulated pipes go to the red-and-white pumping station on the wall. That's the ground loop pump.

Our old heating system had two completely isolated furnaces. With the new system, we are using the one GSHP. Naively, I thought they'd just make a pair of Y's with the ducts. One for the first and second floor supply vents and one for the first and second floor returns. Reality is a lot more complicated. The HVAC installer really had to be creative to get all the ducts connected properly. Like air origami!

For the first cooling data, we observed the water leaving the GHSP at 74 degrees and returning from the loop at 64 degrees.  Given that the ground loop is in 50 degree earth, I sort of expected it to come back cooler, but I guess the analogy is that even an ice cube takes time to melt at room temperature. The good news is that it is cooling.  Need more data to see how efficient it will be.

Lots of little things to finish up on the project. Patching holes in walls, fixing a few things here and there. We spread 3 yards of loam and planted some grass over the weekend. We were fortunate enough to have 5 days of rain to get it started.  We need to get some more loam. We did not realize that we would be without so much topsoil after the trenching!!

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Correction to previous posts: they used propylene glycol not ethylene glycol in the ground loop to keep it from freezing in winter. I was surprised:  Propylene glycol is used in soaps and even dog food.  I think the loop holds about 80 gallons of fluid. About 20 gallons of that is propylene glycol.