Solar oven: 275 degrees!

That’s hot!  It’s enough to cook a rotisserie chicken but 325 would be better.  I aspire to a hotter oven.  I would certainly perspire to a hotter oven…..

I will continue to ‘fiddle’ and ‘fine tune’ it but I doubt that I will get it past 300.  I may have to enlarge the sun-capture panels a bit to even do that.  But the solar oven works – it just takes a bit longer than ideal to cook a chicken according to the You-tube ‘experts’ who know this kind of stuff.  Do I care if it takes an extra 45 minutes?  Not really.  This is a solar-powered chicken cooker brilliantly designed to accommodate a duck as well.  Maybe a small turkey.  Or a skewer of squirrels.  It is supposed to be a start-and-forget kind of cooker.  Put another way: I can afford to accidentally burn a chicken because well, I do forget things now and then…..

….where was I?

Oh, yeah…..the solar oven…..the first improvement I made was to metal tape all the seams.  That did little to help things get hotter but it looked good.  The second improvement/requirement was to construct the solar ‘cone’ capture panels and that was a major upgrade.  I welded a wire frame and then covered attached panel-boards in reflective Mylar.  Turns out that the potential BTUs generated are in a direct correlation with the square foot area of the capture panels.  Bigger silver cone, potentially higher temps.

Then I insulated the entire box again – this time from the outside.  And then, and then…….the temperature ‘popped’ up a whole 50 degrees.  Without following the sun and adjusting all the time, I hit 275 and kept between that and 250 for three hours.  If I sat there in the sun (cooking myself at the same time) and slowly adjusted the angle of the cone to follow the arc of the sun, I am pretty sure I would have kept 275 the whole time.  So, however you look at it, I am NOW cooking without gas.

I know, Wim.  I know.  The test will be in the finally-roasted chicken.  That will happen (or not) Monday (guest arriving).  We will see.  If I get a nicely roasted chicken on Monday, there is no question – this quirky project was a success.  You will all hear about it.  All five of you.

And, of course, there are now a bazillion chores that need my attention after wasting time in the pursuit of a sun-cooked rotisserie chicken.

Could this behaviour be the early onset of something odd?

29 thoughts on “Solar oven: 275 degrees!

  1. Splendid work. Très créatif and resourceful!

    May I ask how much juice your solar panels are producing while the solar oven is going its thing? I ask, because we have a somewhat modest array of 3,000 watts. They will produce a steady 2,000 watts or so, for some hours on a sunny day. Much more than we need to use our counter-top Oster electric oven. It will easily reach 500 degrees (F., not centigrade) within minutes and will accommodate a large chicken, a larger capon, or a compact-size turkey. Or a weighty prime rib roast.

    When the sun shines (or the wind blows), we regularly use our Oster electric oven, our Waring 2-burner electric cooktop and our Breville electric pressure cooker (not all at once, although perhaps we could at times). Better than firing up the wood cookstove on the dog days of summer. And saves propane used by our other cooktop.

    We put a second wood cookstove in an outbuilding some years back, so one could cook there and not worry about heating up the main house. It seldom gets used because, when its use would make sense, we have abundant free electricity. I am guessing your situation might be similar. Of course, you are perhaps going the solar oven route because it takes more creativity and seems more off-gridish than having resort to an electric appliance.

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    • I would like to think I was more practical than just doing a solar oven to appear to be extra OTG-ish but, in truth, I think that is precisely the reason. A smidge embarrassing, I guess. NOT the looks so much (who’s to see?) but rather because it seemed so OTG-ish, I thought I should give it a try. Funky, earthy, climate-change-ish, eco-statement to help offset all the gas and oil I use. Plus, I will get bragging rights from almost everyone ’cause no one out here has one either. There is virtually NO power going to the oven except by way of the rotisserie motor. And it takes only 4 watts. The sun does all the actual cooking. The rotisserie motor is 120V ac but, of course, my 120 power comes from the solar panels and the batteries so it can honestly be said that this oven cooks and rotes off solar power alone and virtually none from MY actual system mostly all direct from the sun’s rays. We also have 3000 watts of solar array. And we can use it like it was an air-conditioned house in Arizona – there is gobs of power. We have extra. From about May to October, we are good without a genset (unless I weld). In fact, I have a small a/c and I turn it on when it is really hot and even then the ‘system’ handles it well (for about 5 hours, tops).

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  2. Well, I remain impressed. I would not have the patience to put it all together and make it work.

    Is it self-cleaning? Driving it up to 800-1,000 degrees for a couple of hours oughtta’ do it, I would think. And that would allow for extra crispy chicken, which KFC in Campbell River does not sell.

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  3. To drive it up to 800 degrees, I would have to add a propane burner (Yes, I thought about that when I couldn’t get past 200). Still, I’ll focus and fuss and get it to 300 and I’ll be happy. And you, my friend, being anonymous but knowing CR and KFC likely means you will confront me one day and say, “Hey! Remember that guy who asked about the solar oven? That was ME!!! Hahahahahah.” No rotisserie chicken for you…….OK, maybe a fish…..

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  4. 275 deg F is impressive for a solar oven especially when you think how far north you are.
    Will the Ravens be hanging around for hand outs?

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  5. Ravens are, oddly, very picky. They will not eat oysters or prawns that have been cooked, for instance. Raw? Yes. But cooked? No. Cheese? Yes. Any kind. Bacon? No. We do not offer carbs. NO breads and crap. They want raw, they want fresh and they want it NOW!!!! Only saving grace…if it isn’t raw-fresh there, this new couple doesn’t linger and complain like Jack and Liz did.

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  6. It is a nicely crafted unit you made. It should get hotter. I cheated with mine. Years ago I bought an
    “All American Sun Oven” with the extra cookware and dehydrating racks package. It will get over 400F in just a few minutes (while empty). Adding like 2 loaves of bread, or anything with moisture exposed or much thermal mass drops the temp a lot. Like, it struggles for 300F+ w/2 loaves of bread. It does work nicely, though, and even slightly browns your bread. Things in closed top pans cook much like a slow cooker. Beans, pot roast, a whole chicken in a roaster, all work nicely. Best results is when adjusting the sun aiming maybe every 1/2 hour. There are “sights” that you aim the unit precisely by directing a spot of sunlight to a circle below that hole. The glass should face directly at the sun. You tip it up and down (more tilt in winter, and earlier and later in the day) with an adjustable length rear leg, and just turn the whole unit for periodic sun tracking. A swinging rack inside keeps your cookware level.

    Just looking at your photos. Your reflectors are larger than those on the “Sun Oven”, however they are not as steep (angle them more upright..). The entire interior of Sun Oven is all black sheet metal inside a fully insulated box, and the cookware is all dark colored thin granite ware (black, glass enameled steel). When the foods get above boiling temp the steam fogs up the glass and the fog reduces the heat going in. I wipe the glass when adjusting the aiming. It closes tightly to a silicone seal and the un-vented oven must be opened to wipe off the fogging. The glass door is held slightly open to vent moisture away when the Sun Oven is used as a food dehydrator. Of course that means oven temps below 140F. You can dehydrate food or make jerky at those temps.

    Hope this helps. Your home made unit, with just a little fine tuning should work much better. The cooking in these ovens is more of a moist heat because of needing to seal them tightly to trap in the heat. A rotisserie oven is more vented and dryer, with larger heat input needed to cause browning, it’s like a broiler heat. Save the rotisserie for the gas grill.

    I have learned to avoid trying to use the Sun Oven on heavy chem trail days. (these happen even when there’s NO forest fire smoke, usually just before a low pressure front reaches the coast). The reflective metallic particulates-filled skies can block enough sunlight to prevent Sun Oven reaching boiling temperature all day. Normally, my pot of beans will reach a boil in 20-30 minutes, winter or summer. Not sure if you have those days there? Here they are not very frequent, thankfully. You’ll know them by the sky being a silvery white haze instead of blue background, and looking at the sun it is surrounded by a large iridescent rainbow colored circle. Forget sun oven on those days… (in fact you might do well to stay indoors, because UV A and B can still be very high on those days, even though visible light is reduced).

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    • Thanks, Kev. Making the cone more ‘vertical’ will be my next try. I was even going to add some reflective square footage to it. And changing the inside to all-black may just ‘pop’ me up a few more degrees again. Thanks for the tip..

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  7. I have tried posting this a few times in the past hours, but I’ll try again. I keep getting a message telling me I am an idiot, don’t I know I posted that message already? Well, no I don’t know. If I posted it, then where is it? Anyway, just in case, here goes:

    Well, okay, if I have disentitled myself to rotisserie chicken, fish sounds okay.

    How about something big that sorta’ looks like an overgrown fish? I am thinking of humpback whales. They are out in force around here this year. I would guess you have no shortage of ’em where you are. They seem to be trying to fill the C-19 vacuum.

    There are a couple of outfits that like to track these things such as sightings@ocean.org and sightings@vanaqua.org. They ask folks to report whale sightings. I have tried to do my part over the years. I am not sure anyone is monitoring those emails anymore. I used to get the occasional acknowledgment, but not this year, even though I have sent numerous reports, videos, etc. So I have stopped. I have also stopped because there is really no time when at least one humpback is not in sight. They stay in front of the house all night and we hear them blowing. Sounds like they are in our living room downstairs. As I write this there are 2 out front of the house leaping out of the water having some kind of celebration. Sounds like cannon shots when they splash down. Out past them is another pair, acting with more restraint.

    So maybe time to live off the land (or ocean) and fry one up. Or squeeze one in your solar oven. I’ll have to Google how to field dress a humpback and check recipes. A baked humpback (even one of the little ones we have seen) will provide a lot of leftovers, after having enjoyed roast prime rib of humpback, au jus. Lots for humpback sandwiches, burgers, humpback and dumplings, humpback fricassee, curried humpback, etc. I might need to find a Thermapen with a longer probe to test for doneness.

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    • Well, the dial is on the outside of the box but the ‘probe’ is on the inside so I am reading the interior temperature. Does the temperature-of-the-day make a difference? Yes. Considerably. The heat comes from the sun’s rays, of course, regardless of the temperature outside but the cold outside (if it is cold) draws heat away from the oven so I had to insulate it to keep the heat from being sucked out. As for cooking, most things will cook at a very low temperature – they say. Two hundred degrees F will even cook a chicken (the scariest of the meats to cook too little) but it takes forever. Two seventy five is within 25 degrees of being just fine. So I am a C- in that regard, I think. Kev’s tips may tip the balance.

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  8. Since my comment is “lost” somewhere on the internet, I’ll try to rephrase my comment.
    Congratulations David, it really looks awesome! And the result is great in my opinion. Of course, the proof will be on monday when you roast your first chicken, I hope you’ll post a picture when you have been succesfull, so we can all enjoy the result. As far as your behaviour is concerned, could this be a “second” or “third” midlifecrisis (or how should we call it?) . A few weeks ago, you told me in a nice phrase that in my case “it was mortality kicking in”. I like this phrase so much, and there is so much truth in it, that I will never forget it! So maybe you are going (again) through this phase, and rather then buying an electrical oven, powered by your solar panels, you chose the “hard way”. I am at this moment building a juice press, I want to grow apples and press my own juice and make my own cider. So as I am building it, Anouk (my wife) sometimes rolls her eyes and sometimes gives me a smile that could mean a thousand things. But basically, she understands that I need this kind of projects to keep me “sane”, and I guess there are worse things that I could do. at least she (like Sal) will have some benefit of our little projects if all turns out well.
    But back to you David, a huge respect for your work, and I hope all goes well (you will prepare some backup plan for your visitors if things do not go as planned I hope ;-))

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    • So far, plan B is raw chicken with potato salad. But I can always fire up the BBQ and finish it off if everyone gets fussy. Women, eh?
      Hmmm….you have pointed out a flaw in my OTG proselytizing. I am urging you to go feral so that you can indulge in projects like well, building a cider press. Hmmmmm…..I suppose you could build a solar oven for your penthouse in Manhattan, too? Maybe going wilding isn’t required? Still, I am here now. And I like it.

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      • Believe me, I’d rather build the cider press on Read Island then here in Belgium. Doing these projects on-grid is just to keep me sane (and in the meantime, I am building experience, which I’ll need when I go off-grid). As I am getting older, there is no time to lose I guess, so gaining experience in building stuff might come in handy in the near future.

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  9. I was thinking last night about when I was a kid and used a magnifying glass to light paper on fire.
    I google Solar magnifying oven and some ingenious items popped up.
    Old tv lenses as magnifiers, etc.
    They were getting some crazy temps.
    1000 F surface temps….fried an egg in a skillet, etc.

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  10. I was thinking along the same lines…like a Fresnel lens, the kind of lens that lighthouses used to magnify candles. I am gonna look that kind of thing up further. An old TV had such a magnifying effect?

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  11. We’ll monitor the local news…if we hear of some forest fires on Read Island, we’ll know how the experiment went. I thought the idea was to roast the chicken and eat it, not to turn it into charcoal 🙂

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      • I guess the Fresnel Lens is a direct heat on a focused area….
        Tough to cook meat directly but boiling a pot would be fun.

        I wonder if you could focus the lense onto a bbq brick or oven brick to get it to 2000 deg f so the radiant heat from the brick would cook the chicken……

        Free heat.

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      • There are people who know what they are doing. I am not one of those. And there are those who will never know. I am not one of those either. I am part of the common masses, the hoi polloi. I stumble around dealing with Murphy and Sally and massive ignorance to eventually get 80% there. That’s my style, the way I roll. My oven WILL cook. It is just a matter of time. Bear with me…..

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  12. Reading about all your experiments, and seeing what you and Sal have built over the last 15(?) years, you have my deepest respect and confidence! So we monitor your blog daily to see the outcome….the proof of the chicken IS in the eating :-)….and a good scotch might mask any cooking imperfections

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  13. I appreciate your faith in me (however misplaced) but I have decided to ‘cook’ for real AFTER the Fresnel lens comes. It was ordered yesterday. Future chicken? Two weeks? But, if and when it cooks, you will be the third to know!

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