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So, @rek and I got super interested in these vacuum tubes that people put on their rooftops.

We've just cooked our first meal with the sun, and are still a bit shocked at how well it worked out. It's pretty cool out today, it was able to cook potatoes thoroughly in an hour.

#solarpunk cooking
in reply to Devine Lu Linvega

The vacuum tubes are designed to keep the heat in, we have also a reflector that concentrates the sun rays. Some people put these little sun dials that works like a bull's eye to indicate if the reflectors are all angled.
in reply to Devine Lu Linvega

I translate the name of the website, because "Sun in our dishes" is a great idea.
in reply to DHeadshot's Alt

we're not going to share the specific brand but I'm sure you can find similar models based on the handle design. We found ours at a local hardware store.
This entry was edited (1 year ago)
in reply to Devine Lu Linvega

That's so cool! 🤩 Which curve is the reflector? Parabolic? Or is it the elusive compound parabolic concentrator?
in reply to Calvin Heim

@clh3 it's a piece of bent stainless that curves to follow the shape of the tube. I'm not sure what its name is
in reply to Devine Lu Linvega

Ooh🤔 that sounds like an involute curve, the first curve segment of a compound parabolic concentrator.
in reply to Devine Lu Linvega

One word of caution 🚧 : I've heard of tubes freezing and breaking if they're exposed to clear night sky -- but this event occurred with vacuum tubes with interior metal tubes filled with water. The research group at UC Merced had to cover their vacuum tube + reflector experiment at night due to hazardous radiative cooling.
in reply to Calvin Heim

ours are different, we use the household type that is normally installed on rooftops.
This entry was edited (1 year ago)
in reply to Devine Lu Linvega

yes, they are pretty great when there's sun! I even "baked" with them - but it's more suitable for "steaming". In a good sunny day in London, it takes only ten minutes to boil water.
in reply to Nina Kalinina

@nina_kali_nina When you boil water, do you pour water directly in, or do you have a long skinny pot that you can slip inside?
in reply to Devine Lu Linvega

cool little solar oven! Does the tube-nature of it actually aid in the cooking process or is just a convenient reuse of vacuum tubes?
in reply to Devine Lu Linvega

I love those GoSun solar ovens. But with import taxes and shipping too expensive in the EU. Didn’t found a good alternative yet. Hope it works out for you! Looks good.
in reply to Dan Moved to Retro.social

we bought it, as we don't have access to a machine shop to make the reflector.
This entry was edited (1 year ago)
in reply to Devine Lu Linvega

oh wow, I’ve never heard of these! I’m off-grid, propane range, will def be checking this out. I remember baking biscuits in a solar oven as a child, basically a cardboard box lined with foil 🤔
Unknown parent

Devine Lu Linvega
@matt It's currently 8'C right now, and windy. But clear sky.
in reply to Devine Lu Linvega

Hello! I found this post via a boost from @baba_lilith (thank you!). I’ve wanted one of these solar ovens for some time 😍 does it clean easily?
in reply to Elana

@elana @baba_lilith we're about to find out, we're having lunch in a minute and will clean it after. I'll let you know 😀
in reply to Elana

@elana Cleaning was very easy! Used a little green scrubber for the tray.
in reply to Devine Lu Linvega

amazing!! That was really my only hesitation about getting one myself! Thank you so much for sharing your experience ☺️ off to go see where I can source one…..
in reply to Elana

@elana aliexpress sells the tubes for 90$ish. If you can make your own reflectors that's a pretty good deal 😀
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Devine Lu Linvega
@NicholasLaney @slew it's not pressurized I think. The vacuum part is the double-walled glass tube.
Unknown parent

Devine Lu Linvega
@AtotheJ @nina_kali_nina thanks! we'll try it out tomorrow
in reply to Devine Lu Linvega

I'm wondering whether these are viable for me (southern England), and guessing not. Where do you live, please? (Approximately!)
Unknown parent

Devine Lu Linvega
@RebeccaBoyce we don't have a roof(we live on a sailboat), but you just need an area exposed to the sun.
in reply to Devine Lu Linvega

I had never seen this. Interesting. Could even be useful in certain environments where a fire/smoke might attract unwanted attention.
in reply to Devine Lu Linvega

wooooow what!

"...pretty cool out... cook potatoes thoroughly in an hour."!?

Sarah and I were looking at these a few months ago (probably you linked haha). Thats waay faster than I expected! Sounds actually good!

They were quite expensive though?
in reply to Hamish

@kor if you have the means to making a reflector, you can get the vacuum tubes on their own on aliexpress or in group-buys for 90$ish
in reply to Devine Lu Linvega

We've been cooking from solar for the past 4 days. So far we've tried potatoes, seitan, brussel sprouts and today we're cooking legumes for the first time.

🌻 The big advantage of using the sun to cook our meals is that instead of using the pressure cooker over the gas stove, which creates a lot of moisture in the galley, we'll be able to make our meals in the summer without heating up the habitat!
in reply to Devine Lu Linvega

today's conditions: 6°C, light wind, sunny :>.
This entry was edited (1 year ago)
in reply to Devine Lu Linvega

don’t forget the advantage of the satisfaction that comes with using fire that you stole from the gods
in reply to Devine Lu Linvega

It blows my mind how hot it gets, check out the steam coming out of the vacuum tube-

uh oh I angered it
This entry was edited (1 year ago)
in reply to Devine Lu Linvega

I saw "vacuum tube" without context and assumed you were getting into really retro computing
in reply to Devine Lu Linvega

I 100% cannot justify owning one of those as we have a great electric stove powered by mostly clean BC hydro, but you’re making it look really fun
in reply to vacuumbeef

@vacuumbeef depends on the food inside, but it starts to steam in about 15 minutes.
in reply to Devine Lu Linvega

I want to try it so much, I just can't get my head around the fact that it's real, haha. I found this pipes in local stores, so maybe this summer... I'm thinking maybe a stainless steel sheet will be good as a diy reflector.
in reply to vacuumbeef

try it out and document your experiments, I feel like more people should know that it's possible. It's good for when the grid goes down or when LPG runs out. We'll try all sorts of different foods and collect the cooktimes and weather.
This entry was edited (1 year ago)
in reply to Devine Lu Linvega

Soaked dried chickpeas overnight, perfectly solar-cooked in about 1h30. No steam inside the boat, no fuel used. After an hour we re-oriented the reflectors.

Next, we'll try rice and bread.
This entry was edited (1 year ago)
in reply to Devine Lu Linvega

This is so cool do you think this would work as a total replacement cooking method vs gas?
in reply to calutron

unlikely, but who knows, it will reduce our consumption of LGP considerably in the short term.

I think we're satisfied to have found a way to stretch the length of time we can stay away without refueling, and a bit of redundancy for cooking since our inverter and battery bank are not powerful enough to drive an induction plate.
This entry was edited (1 year ago)
in reply to Devine Lu Linvega

would it work to have an array of them where you've got like four parallel tubes. Curious how scalable it is
in reply to Devine Lu Linvega

ah, your using the tubes. Brilliant idea. I use my 'spare' solar to heat water from about now to sept. But I have space for big panels. Of to go find some tubes!
in reply to Devine Lu Linvega

Nice! Just be sure to not use this on more toxic legumes like kidney beans, because the temperatures reached in there might not be high enough for it to be safe.
in reply to Devine Lu Linvega

ooo you could make little buns! Or one cylinder of bread. 🍞
in reply to Devine Lu Linvega

🌻 I'll stop freakin' out about this soon, promise.

Made some pasta sauce(ground beets, tvp, kale, garlic, zataar) and left it out for 45 minutes in the vacuum tube, in the afternoon sun. Turned out so good.

#theGalley
This entry was edited (1 year ago)
in reply to Devine Lu Linvega

please keep sharing. This solar food cooking tube is so interesting.
in reply to Devine Lu Linvega

every time you post about this i think of the Mr. Wizard's World (80s kids science show) episode where he cooks breakfast on a variety of solar contraptions, including some shiny metallic funnels on sticks!

8 year old me thought it was the coolest, of course, but these vacuum tubes are even more neat.

The episode is available here: https://www.youtube.com/watch?v=3bObVFVu_3A
in reply to Devine Lu Linvega

it's really cool tech, i first found it through Kirstren Dirksen video of a nomadic shepherd (13:30 onward)

https://youtu.be/U54HRmglYEA?t=812
in reply to Devine Lu Linvega

That looks amazing ❤️ How do you clean this, though? 🤔
in reply to moonglum

@moonglum the tray has a standard bolt fitting at the end, and we can screw on a round scrub pad. We've been using it twice a day everyday this week, and each time we use it, the steam seems to clean the left-over of what we cooked before.
in reply to Devine Lu Linvega

oh we got one of those as well! It’s extremely satisfying to cook from virtually nothing
in reply to Devine Lu Linvega

not much, just veggies. I do wanna bring it to a park and cook some Hot Dogs though
in reply to Devine Lu Linvega

can/should one use oil? Or how does sauce-making work in this thing?
in reply to geography

@geography yeah, we made potatoes with olive oil as one of the first recipes we tried.
in reply to Devine Lu Linvega

so cool. That is way more effective than I'd think. my kids had to make solar ovens out of foil and cardboard for school. they could cook eggs and stuff in it.
in reply to Devine Lu Linvega

I've been waffling about getting one of these for years but after seeing that video I'm sold.
Unknown parent

Devine Lu Linvega
@tty the vacuum in vacuum tube refers to the bulb itself which is two-walled. The little slit on the second picture here is a hole that lets the steam out.
Unknown parent

Devine Lu Linvega
@tty it's on our plans to try to boil water 😀 We'll let you know how it goes. Apparently it's safe.
Unknown parent

Is this something you would use to, say, boil water? Would that be awkward to handle, or would you slide in a, say, glass container OF water to be boiled?
in reply to Devine Lu Linvega

I was wondering how you tell how far along you are in the cooking process with the vacuum tube solar cookers?

Is it time? smell? can you see the food? or do you have to open it and look? And if you do have to look, does that increase the cooking time depending on how impatient you are?

Also given the long skinny nature. I'm curious if baguettes work.

Can you fit an oven thermometer in there? I think the vacuum tubes get hotter than you can get with less insulated cookers.
in reply to Diane

@alienghic
> I was wondering how you tell how far along you are in the cooking process

We open it and taste it.

> does that increase the cooking time depending on how impatient you are?

A bit, it'd be like opening the oven to look at the food. Our understanding is that tubes cook at around 200'C, so we monitor it closely.

> I'm curious if baguettes work.

We're planning to try bread soon.

> Can you fit an oven thermometer in there?

We'd like to get one, but we haven't yet.
in reply to Devine Lu Linvega

Thanks for the answers!

I wasn't sure how long it'd take to recover it's temperature after opening.
in reply to Devine Lu Linvega

this looks interesting. Habe you got a link where someone could aquire something like this? I imagine it needs full sun? (No cooking on cloudy days).
in reply to Katharina

@Katharina there are a few companies that sells them. We found a local importer of those. Look at the local hardware store, otherwise if no options are available, some grocers might be able to order the tubes.

If you're in Europe, you're lucky, there are often group buys of those and workshops.

We managed to cook with an overcast 2 days ago, it just took longer.
in reply to Devine Lu Linvega

This is amazing. It makes so much sense, especially at sea. I wonder if it is possible to bake a baguette, the shape seems perfect for that 😄
in reply to domnantas

@domnantas we're working our way to bread, trying out all the easy stuff first.
Unknown parent

Devine Lu Linvega
@jameschip Today's experiment: Rice!
Unknown parent

Devine Lu Linvega
@jameschip we wondered the same thing yesterday, but it would likely just get stuck as it expands.
in reply to Devine Lu Linvega

@jameschip Get stuck how? The “pop” is usually violent enough to make any needed room and fill out a volume of space. Popcorn pops at 180-200C, so I suspect it would work on a sunny day
Unknown parent

Devine Lu Linvega

@lrhodes that was the first thing we tried 😀 and yes.
https://merveilles.town/@neauoire/110085447767614654


So, @rek and I got super interested in these vacuum tubes that people put on their rooftops.

We've just cooked our first meal with the sun, and are still a bit shocked at how well it worked out. It's pretty cool out today, it was able to cook potatoes thoroughly in an hour.

#solarpunk cooking


in reply to Devine Lu Linvega

I am so into this. Did you buy the cooker or make it yourself?
in reply to Spencer

@spencer we bought the vacuum tube and reflectors combined. We don't have access to a shop where we could make it.
Unknown parent

Devine Lu Linvega
@jfmblinux aliexpress sells them, there's a bunch of outlets depending on your location.
Unknown parent

Devine Lu Linvega
@therealraccoon keeping things warm
Unknown parent

Devine Lu Linvega
@jameschip not sure if can tell the difference. Maybe things are less wet than in the pressure cooker.
Unknown parent

Devine Lu Linvega
@jameschip we put water with it, like you would make rice normally.
in reply to Devine Lu Linvega

Cool! (Or should I rather say “hot”?!j) what to search for to get more information?
Unknown parent

CoolBlenderKitten
@klardotsh
Oh, I was wondering about that, one can buy them? Where would one go looking for something like that?
I was not sure of its home made of bought but it's super amazing!
in reply to CoolBlenderKitten

@CoolBlenderKitten @klardotsh we found ours at the local hardware store. There's different models in europe and america, I think Himin is the only company that makes the tubes tho, you can order them from them directly.

There are a few group buys going on.
in reply to Devine Lu Linvega

very cool! I wouldn't mind trying this at home and when camping.
Unknown parent

Devine Lu Linvega
we don't. The reflectors capture the sunlight and the vacuum tube keeps it inside. We've been experimenting trying to cook all sorts of different meals, we'll release our notes soon, we still have a few experiments to try out first 😀
This entry was edited (1 year ago)
in reply to Devine Lu Linvega

Am I right in assuming you have to live somewhere warm for it work? I'd love to try it, but...

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