Solar irradiance above the atmosphere (i.e., in orbit) is 1360 W/m^2. At ground level, it’s 1120, so a loss of ~18% due to the atmosphere.

If transmission losses plus the massive costs of launch, keeping the panels cool (no conduction/convection in space), and maintenance add up to greater than 18%, it’s more efficient on the ground.

I’ve only really seen commercially available thermal batteries for heating, but i think it’s absolutely a solvable problem for cooling.

The idea is that you heat (or cool) a large thermal mass when energy is cheap, and then you distribute that heat (or coolness?) later. Water is the obviously easy thermal mass. The math (and usage) is pretty easy for heating since the amount of energy stored is just massspecific heatdelta_T.

For cooling, you can take advantage of the huge amount of energy it takes to freeze water. For example, it takes about the same amount of energy to go from ice-liquid water at 0°C as it does to then heat that water to 80°C. The trouble is that you can’t just pump ice around like you can hot water, so the system has tools be more complicated.

Everyone (including me) wants rooftop solar cause it seems like free real estate and the idea of having your own power generation is nice, but ground-based systems are definitely better.

And obviously that’s separate from the benefits of community solar.

Ah, yeah, forgot that was another one I’ve done. It seems like I’ve taken apart most of my household appliances at this point.

Until you do like step one of taking an appliance apart, and realize that the real manual is marked “for technician use only”, and it’s hidden inside of the appliance.

My washer and dryer both have good manuals complete with circuit diagrams under the top once i take a few screws out. My chest freezer has one taped up under the hatch where the compresser sits. My refrigerator has one hidden in the door hinge.

If you haven’t seen it:

https://www.youtube.com/watch?v=URvWSsAgtJE

Seriously, I think a big part of solarpunk ethos is combating the notion that everything has to always be available 24/7. Society pays a lot to deliver every convenience like fruit out of season from the other side of the world.

One of my friends had their water hookups backwards, too, and they had no clue until I checked after they complained to me about how all their clothes were shrinking despite only ever washing on cold and hang drying. Sounds like a nice feature to have a sensor in there.

I’ve definitely got a soft spot for any electromechanical appliances. Computers have gotten so cheap that every appliance built now runs on them, but it’s much harder (for me, at least) to do anything about it when one stops working.

• My chest freezer stopped working, and i was able to put in a new relay for $2. The circuit diagram made it easy to diagnose with a multimeter. Oddly enough, i had to buy a 10 pack, so i likewise have a bunch of spares I’ll never need.

• My dishwasher stopped working, and the manual specifically showed which wires to connect to to test resistance of each component to see if anything needed to be replaced. It turned out that the float was gunked up, so it read as having enough water even though it didn’t.

• My fridge ice maker stopped working, and I just had to stick in a jumper wire to put it through a test cycle that immediately made it clear what was going wrong (a short), and i was able to fix it.

This is all in contrast to my clothes washer that runs on a computer, and it gives me an error message that basically just means “it’s not draining right”, and there’s like 8 potential causes, and I’ve tried to address them all, but it’s still get the error message.

You can still work with that a bit. Basically you just want to have stuff other than just non-native turf grass. Even having clover mixed in makes your lawn not need fertilizer to stay green, and it has flowers that benefit insects. Dandelions and plantains can grow anywhere, and they both produce edible greens, and they basically show up on their own.

There’s two broad categories of ways that concrete can get messed up: things that apparently ruin a batch on the spot, and things that compromise the resulting structural integrity in ways that might not be readily apparent.

The biggest things I can think of for the first category are water and time. More water means more “workability”, so it flows better, but it means the overall strength goes down. You basically want to use a minimal amount of water you can get away with. More water also means more time to set, so concrete workers will add water to the mix in the truck to slow it down if they need to. You can always add more water, but you can never take water out (or add more cement/aggregate on site). Concrete trucks have a water tank on board to add water, and also clean off equipment after pours because job sites often don’t have water. If enough water is added to the concrete in the truck, the batch is ruined. I’m sure there are compounds that could ruin a batch, but the water is right there.

Time also hurts because there is a ticking clock for getting the mix out of the truck once it has been made, particularly if the batch plant is far from the work site, and weather is hot. If the site is not completely prepped and ready to go when the truck gets there, enough delays will force the whole batch to be scapped before it ruins the truck. A lot of work goes into getting forms set properly and squared, and the underlying gravel compacted, so that is all delicate before the truck gets there.

The second category, things that compromise the integrity over time has a lot of potential, but there is no guarantee that strength will be compromised enough to cause failure, and there’s a lot of potential for collateral damage if it’s in a bridge, building, or something people could be on/in. The first things that come to mind here are stuff that will decay over time resulting in voids, like woodchips. I know there’s been research into woodchips as an intentional additive, but I’m sure there’s more science that goes into that than just tossing it it. Something that causes oxide jacking would also really increase failure rates. This is when a material like steel rusts and expands, splitting concrete apart. This happens often if rebar is not fully encased in concrete. This does happen eventually to any reinforced concrete, which is why modern concrete structures have design lifetimes unlike Roman concrete which lasts indefinitely, but has to be much more massive. Adding a bunch of nails or something like that to concrete would probably speed up the process, but enough nails/woodchips to make a difference would most likely be noticed by the people doing the pour (which could actually be a benefit).

If you wanted it to be unnoticeable, you would probably want to get a roll of rebar tying wire, and figure out a way to get it placed in the prepped site in such a way that it would be exposed to the elements after the final pour without being easily noticeable by the people doing the pour. Bonus points if the effort is focused on areas of stress concentration like corners or joints in the concrete.