World’s Largest Solar Steam Cooking System

Found this article this weekend about India creating the world's LARGEST solar steam cooking system. It has 73 solar dishes that will be able to feed 20,000 people, TWICE a day!

Cassie Langstraat wrote:Found this article this weekend about India creating the world's LARGEST solar steam cooking system. It has 73 solar dishes that will be able to feed 20,000 people, TWICE a day!

To make matters better, the dish design is open and freely available. Also available are some different types "watch works" for keeping the dish focal point where it belongs so long as the sun is up. (the ones I have read about are water powered and work by time not detecting the sun's position) While the system posted by the OP feeds lots of people, (the heat is turned to steam to get to the kitchen) there is a single dish variant designed for a small bakery that this one is based on. There have also been experiments of using them to heat a mass or phase change material for cooking after dark. Far from a novelty these various installations are in daily use and have paid for themselves many times over... which means that climate is very important. Cooking doesn't happen when the sun is not out. These are designs for places that have sun pretty much every day. On the other hand, if a person wanted to be diligent about things, they could save half or more of their cooking bill by just using it when the sun was available. Most people hold convenience as more important though.

Exactly. Open source designs = hell yes.

Very true about people gravitating towards convenience rather than doing good in the world..

Make freezer to crock pot meals and use a solar collector to heat a pot in an insulated box.
Drop the frozen meal in the pit in the box. The meal stays cool in the insulated box until the concentrator is hot enough to cook it. It cooks, and stays hot until you're ready to serve.

Sell it as a kit and make a fortune selling the branded frozen meals to cook in it...

Sounds Like a great idea Connor. Have you tried it out? To make sure it works? Ha

I've made meals that go from freezer to crock pot and can stay in a warm crock pot for a few extra hours without harm.
I haven't built a solar concentrator steam cooker, but building an insulated box and a coil for the steam to heat the crock pot should be pretty easy.
Even a DIY solar concentrator and boiler doesn't sound that difficult.
Safety testing it for commercial sale in the United States sounds daunting.

Hah yes, that is quite daunting for sure. But if you do try it out, let us know! I would be interested in something like that.

We've been using two of those reflector-concentrators for about 15 years. It was a Swiss NGO that installed it, as a workshop with our students, who had to do all the welding and paint the silver backing on glass and cut the mirrors, etc. All the mirrors have been replaced several times over the years.

The cool ingenious (Swiss) clockwork that tracked the sun kept breaking so eventually we gave up and track it manually every few minutes. It was powered by muscle in the morning, stored in a stone tied to a cable and pulling down all day, controlled by a pendulum going tick-tock along a bicycle chain.

The most important element, and easiest to miss out on, is a cook who is willing to time things right and dammit, USE the thing! Our previous cook was very resistant: "Nah, can't be used, the food goes mushy, forget it!" But happily, our current cook, and he's going on 10 years here now, uses it a lot. If the weather is sunny, there's always one pot on each of the two units, bubbling away or cooking dal in the big pressure cooker or heating up the tea, or even sizzling a curry.

Rebecca that is awesome! Thanks for sharing! Those images are great too.

Rebecca Norman wrote:We've been using two of those reflector-concentrators for about 15 years. It was a Swiss NGO that installed it, as a workshop with our students, who had to do all the welding and paint the silver backing on glass and cut the mirrors, etc. All the mirrors have been replaced several times over the years.

Good to hear of some being used regularly. I am told the dish actually changes shape as the year progresses to keep the focus point the same shape for maximum concentration.

For those interested in building one, look up scheffler solar concentrator. It is getting harder to find stuff as some of the web sites have vanished.

What about heating oil to store heat for later use?

adam sheppard wrote:What about heating oil to store heat for later use?

Please do. share experiences after in this space.
- please note that it would have to have no oxygen in the mix. While oil will stay liquid hotter than water, it does burn much lower than steam (steam doesn't burn).

That is not meant to say don't do it so much as "do research fully first"

There is IMO a need for study in this field. Right now the normal thought is to use the heat when the heat is there... make more heat if not. As some people have already pointed out, one of the best places to store heat is in the food itself using straw box technology. That does limit the kinds of food that can be cooked that way. This should not be a problem if other types of food are cooked "when the Sun is shining". However, high temperature, low loss heat storage would be a real plus.