Aaron Yarbrough

I am just south of Austin. I installed some cooling tubes about five feet deep for an earth sheltered structure. My results were not great. In the beginning, the air temperature in the tubes was pretty consistently in the mid 70s but once I started pulling air through they warmed up significantly. As summer wore on the base temperature in the tubes crept up into the mid 80s. Also, my run wasn't long (~25 feet) so I'm sure that was an issue as well.

If you're going to dig, I think you would be better served by building a walipini-like sunken greenhouse.

Fore reference, here's an explanation of how I built my cooling tubes:

David Baillie wrote: Lithium is a game changer as well as you can get full array production since they have low resistance to charging unlike lead and you don't waste time at the high voltage low amperage low production absorb stage. It has forced solar designers to change their ways as we now maximize panel numbers due to low panel costs as our first priority. On the down side you are usually best to repanel completely so you can maximize your strings and the all in one inverters are terrible at lead acid charging as they lack a proper 3 stage charging profile.

We woke up with no power a few weeks ago. One our 6V FLA batteries had a bad cell I think. Fortunately, I had recently received a lithium battery kit and was almost finished assembling it so we we didn't have to limp along for long. The difference between the FLA battery bank and the Lithium Phosphate one is amazing. We're still getting summer temperatures here(two months out from the winter solstice) and I'm running two mini splits, a convection oven, an induction cooktop two fridges and it seems like I can't run the battery out of power. Then with 2-3 hours of full sun it's back to 100% charge. I ordered more solar panels which I will still install but it definitely appears like the weak link of my system was my battery.

 

If the shed is on pier and beam blocking off the crawlspace to keep the wind out will help keep the space warmer.  

Is the shed foundation pier and beam? If so you could cut out the plywood subfloor to access the joist bays to put in mineral wool batts. It's not too tricky especially if the plywood was put down with screws.

John Carr wrote:
I should have mentioned that I'm in the northeast, only an hour and a half from the Canadian border. My water inlet pipe has to be down at about 5' to avoid freezing, so I'm hesitant to make an exterior housing, even if insulated. The water's coming in on the north side of the house so I have to battle the cold where it emerges from the trench.

I'm thinking of putting in a small 'basement' within the edge of the foundation (maybe 5'x5') that I can access through a trap door in the inside floor to turn off the water. But maybe this is not necessary? Otherwise I can just run it up from the trench through the soil, and maybe since it's within the perimeter of the foundation it's not in danger of freezing? I would just insulate the foot or so from the underside of the floor down a foot or two into the soil.

Our frost depth here is about 2 inches so hopefully someone with more cold climate experience will chime in. In a really cold climate I would run the water pipe below frost depth into the building footprint and stub it up in an interior wall.  

John Carr wrote:
how do I run the water inlet and septic outlet through the rubble trench foundation? Do I just put it among the rubble and hope it won't get crushed? Or do I need to build a small "basement" from concrete block or something to house the water inlet and outlet?

I would run a 3 inch waste water line through a piece of 4" pipe in the area around the trench to protect it.  For the water inlet you could do something similar but with a long sweep 90° elbow through the grade beam or build an  insulated exterior housing and run the water line in through the wall.

If you keep water away from your foundation(by having large roof overhangs, installing gutters, and grading  the landscape to move water away from the foundation) I think you will be fine not using geotextile fabric or drain pipe. I've installed drain pipe on the two rubble trench foundations I've done and I'm pretty sure it just gets crushed anyway. As an alternative to geotextile you might consider using burlap instead. It will break down eventually but should help initially to keep sediment out of your rubble trench.  Hopefully, by the time it the burlap is compromised you have the roof on and the soil around the site has stabilized so incursion isn't as much of an issue.    

So, I found an aerial shot of my property and I guess I could do with some tree trimming....

Winter 2022 Aerial Image of Solar Panels

Granted, it looks like this picture was taken late afternoon in the winter.

Rico Loma wrote:I forgot to add:
Try different chainsaws as you work on tree trimming, please. I am no expert, but  I keep learning as i go.  Also over time I have learned more about balance and accuracy while cutting at 20-40 ft elevation. Certainly recommend electric  14 inch and 6 inch saws if possible,  the lack of power is counterbalanced by great results,  

I have a 12 inch green works saw that is pretty light but I might pick up a six inch saw as well.

David Baillie wrote:
I would say you hit the nail on the head. The new generation of all in one inverters have taken over from the more traditional transformer based units. Along with multi charge controllers for different producing strings you also get code approved 2 way communication with the new lithium battery packs. Lithium is a game changer as well as you can get full array production since they have low resistance to charging unlike lead and you don't waste time at the high voltage low amperage low production absorb stage. It has forced solar designers to change their ways as we now maximize panel numbers due to low panel costs as our first priority. On the down side you are usually best to repanel completely so you can maximize your strings and the all in one inverters are terrible at lead acid charging as they lack a proper 3 stage charging profile. The EG 4 mentioned above is a rebadged lux inverter, LUX being  my prefered inverter these days. Solark is another name to check out. Being in Ontario I am forced to comply with UL9540 which is rules around 2 way communication between battery and inverter so not all brands of batteries will qualify. These days I am installing Pytes batteries.  Its a brave new world. I fully agree that your first step should be aggressive trimming. Also mentioned was bifacial panels... They would be of no real benefit to you on a roof as they can catch no reflection on the back side.
Cheers,  David

When I built my system I got a quote for lithium batteries and it 4 times that of FLA battery bank I ended up with. Now, I could get a bigger lithium battery for less than my batteries cost.