Hi, everyone! Here is a progress update. We've had to replace one of the fans already because it failed (cheap Chinese part). It's been insanely hot here with our delayed monsoon start, and the unit just has a lot of trouble keeping up. We realized that we need to open up the hinged cover on top of the outside fans when it's hot or too much heat sticks around by the chips. We're going to scrimp and save and spring for another panel and additional peltier chips with a liquid cooling set-up and add that on to what we already have.
The good news so far is that it maintains root cellar-like temperatures pretty well without having dug a root cellar yet. This means that, since it's dark and cool, the chayote I bought at the Mexican grocery store and hadn't eaten yet sprouted, as I described in this thread:
https://permies.com/p/956187. The bad news is that my fermented beverages are still exploding, or at least, one more exploded yesterday (tepache like I mentioned in this thread:
https://permies.com/p/956468). We didn't have ice bottles to add for a few days because we'd filled up the Sundanzer freezer with a huge batch of chili, and although we use those frozen containers of chili (used plastic ~2 lb. coffee containers) in a similar way to the ice bottles, cycling them into the cooler when we need to start defrosting them, it doesn't work out quite as well in terms of timing and cooling.
One thing we figured out is to keep produce in shoebox-type plastic storage containers -- with a towel or cloth in each one to absorb moisture -- inside the cooler so that the condensation doesn't make things mold. Mostly, though, we try to just use produce right away, freezing or fermenting or dehydrating it if we're not going to cook and/or eat it soon. For example, I bought ingredients for a batch of giardiniera/escabeche (carrots, onions, mixed hot peppers, cauliflower, jicama, garlic, oregano) and got a gallon crock of that fermenting, but had hot peppers left over, so chopped them up and froze a quart bag full of them in preparation for this latest batch of chili.
Jeremy Baker wrote:My understanding is there are wide temperature changes there in the semi arid region. That makes design a bit more challenging and opens up possibilities. As was mentioned earlier that placing food outside at night or seasonally can be effective.
I wonder if you could run water through “chillers” at night and store cold water. Basically solar hot water panels running in reverse. A tank in the ground (root cellar) and a tank up in the air above the collectors. You would have some cold water and some hot water most of the time. And a pump may not be necessary if it can thermosyphon due to convection.
There are large “chiller” panels from big refrigeration walk in coolers. I had one and wish I still had it. It was aluminum and I think it originally had ammonia or a refrigerant in it. These would be interesting to play around with.
Thanks, Jeremy! There are wide temperature changes here in many seasons, but unfortunately when it's hottest -- after monsoon clouds have started swirling but before we've had any significant cooling rains -- the humidity rises and keeps the overnight temperatures from dipping very much. This is always the most challenging period of time for us with refrigeration.
I need to find out more about the chiller panels you mention! Got to do some digging. Thanks!
frank li wrote:Sounds like the Sun Danzer has proven its value. When refrigeration was not possible it was producing ice to aid in heat removal! A matching fridge would likely end your issues with a slightly improved pv system....
Dissapointment is a type of cost associated with alternatives also....
Dont give up on lead acid. It is simple, robust and state of the art technology as opposed to "state of the finnicky coin flip" and your system will function without dissapointment and with longevity if you dont place unrealistic demands on it.
Thanks, Frank! It's true, the Sundanzer is great and we make heavy and satisfied use of it, but (unfortunately or fortunately, depending on perspective) we can't afford another -- either the unit itself or the system expansion it would require -- especially given that, as I've mentioned, we can do without and it's not really that much of a sacrifice (by our standards -- we are crazy desert rats, I'll admit). We do feel a substantially smaller investment to continue the current experiment and try to improve its performance is both doable and worthwhile.
I have definitely spent most of my life agreeing with you about disappointment being a cost associated with alternatives. I would describe myself as deeply risk-averse. It kept me safe, i.e. I kept jobs I hated rather than start my own business or go freelance, and although I'd been obsessed with off-grid sustainable living and things like permaculture (although I didn't learn of such a design system until later) since leaving my parents' home, I didn't really do much about it. That is, until I started to throw caution to the wind, at least every once in a while. Since then, I'd say a relatively small percentage of my attempts or experiments have been successful, especially in a way most of the world would recognize, but I'm a good deal happier, and I'm learning a huge amount every day. Not only that, but even though individual attempts may fail, somehow we seem to have still accomplished a lot. My partner either learned these lessons far earlier than I did or started out less risk-averse. Either way, he was already off-grid and quite self-sufficient by the time I joined him here, and much of our experimentation originates with him. I believe that if we let disappointments -- failed plant experiments, earthworks not flowing the way it seems like they should, etc. -- get in our way then we're not learning as much and we're not innovating in a way that I believe we all need to in order to make it through our current planetary challenges. I know you weren't saying that disappointment should stop us necessarily -- just that it is a cost -- but I wanted to throw that out there, as a manifesto or
modus operandi.
Is there a good discussion about batteries here that I haven't found yet? Can we at least seek better alternatives to lead acid, even if we don't give up on it entirely? What I've heard/read is that there are arguably already multiple better alternatives to lead acid that have been around a long time -- like the Edison nickel iron battery, which even though it's early 1900's technology is still called the "most rugged and longest lasting battery option available today" -- but got pushed aside by moneyed interests and agendas, but this is far from my area of expertise and I'd love to learn more.