I think I'm ready for the big day tomorrow. It might be a bit hard to sleep tonight!
Yes, that's another 100' roll of 160 PSI piping. The previous 100' for the supply/return line wasn't enough! If I'd known I was going to locate the ground loop so far down the hill I would've bought the 500' roll to begin with ($120 + S/H). The colder summer ground temperature should easily be worth the small pressure loss. (There's also room and should be pump capacity to install another buried coiled loop to the right of this one, if desired.
Because of the higher than expected restriction, and the lower than expected power consumption of the Iwaki, I'll probably connect the PCs to the loop through plated heat exchangers. Doing that and cracking open the bypass valve should avoid all potential condensation problems.
My loop last summer was more than 5c higher than ambient when loaded so its possible to drop more than 10c off the intake water temperature and stay above the dew point. Going slightly below it isn't immediate doom and gloom either, but that area could be viewed as the safety wiggle room.
A couple pictures:
The pressure gauge and filter valve installed. Now I can remove the filter without spilling out the top water content of the reservoir.
Here's some of what the filter had in it. I wasn't very careful when working in the crawl space. Without the filter I would've had to cap all the tubing when moving it and have kept all the fittings in plastic bags.
Anyone care to guess what the ground temperature will be? 12 feet under
, in wet higher water table soil
The constant ground earth temperature is supposed to be 58 in the coastal area here. So I'm expecting to see a temperature slightly below 50 tomorrow based on these:
"A minimum delay of five days between loop completion and test start-up is
recommended in formations that are expected to have low conductivity [< 1.0 Btu/her-ft-Â°F (1.7 W/m-Â°C)] and three-days for other formations."
It looks like the final settled ground temperature will take a little while to get, but I'll have IR readings of the excavated soil tomorrow.
We're going to risk not using any sand as a dressing because of how wet the soils going to be. The coiled loop will need to be lowered immediately after temporarily scooping the muck out of the trenches finalized depth. Once it's down there, its going to float or potentially be raised by mud sliding in from walls. It'll need to be immediately backfilled from a pile of pre-screened soil to keep it in place. All the water should prevent air filled pockets of soil from remaining around the coils. This installation definitely won't need to be filled from a garden hose.
That's the expectations anyway. Only 14 more hours and we'll find out.