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Heat retention cooking with a solar panel, two pots and a silicon heater.  RSS feed

 
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So today I tested using a silicone heater inside of metal pan which was inside another metal pan to heat 4 cups of water. Water got very close to boiling, but I also noticed that the other large pan was acting like a heat sync. So I think I i will use more silicon pans for insulation. the temp was hot enough to cook, it was hooked to a 220 watt solar panel, so seeing these results for the first time with just a little more refinement I should be able to cook directly from the solar panel with this heater, then let the retention heat cooking finish the job like a crock pot.

But not bad for the first testing round.

Mart
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pollinator
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Location: mountains of Tennessee
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Containing the water inside a mason jar or something similar might help. Space blankets might too. Those things helped my solar oven. So did adding some thermal mass in the form of slate tiles. A turkey roasting bag also helped. Have you tried an immersion type coffee heater to heat the water? I also used solar panels & a charge controller to charge a battery & then used an inverter to run a hot plate. That worked good to.
 
Mart Hale
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Update:

I figured out that I could take my present heat retention cooker and convert it to use the Silicon heater to heat the food!!!

I did this via solar power today a cloudy day so I am very happy about that     I now have another way to cook that takes very very low amounts of energy compared to my insta pot.

Insta pot takes 1000 watts, but then again it is only doing that for 15 min, so it might be the same amount of energy only shorter time as I think about it.

Warning to those who my try to follow in my foot steps be sure if you drill a hole in the bottom of the pan to leave room for the steam to escape else BOOOM!    you have been warned, I am planning on adding a safety valve to my setup.

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Mart Hale
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>>

Mike Barkley wrote:Containing the water inside a mason jar or something similar might help.
>>Space blankets might too.
>>Those things helped my solar oven.

Which solar oven did you use them in?     I have a sun oven...


>>So did adding some thermal mass in the form of slate tiles.

What are slate tiles?      I have been thinking of adding these to my solar oven, I have tried bolts but they do seem to loose heat quickly.


>>A turkey roasting bag also helped.

Yes this worked well in my cool kit type solar oven.


>>Have you tried an immersion type coffee heater to heat the water?

I like the thought of them but I don't like aluminum as the heater, I might consider it if the heater was stainless steel...


>>I also used solar panels & a charge controller to charge a battery & then used an inverter to run a hot plate.
>> That worked good to.



I have 3 solar setups, and that is one of them that use.    I use a Tesla Model S lithium battery module  for the main battery, and I love it :-)








 
Mike Barkley
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fyi it's simple to compare the 2 systems to each other. Wattage X time = watt hours. So, 1000W X 0.25 hours = 250 watt hours. The power supply shows output watts on the label so just multiply that (for the specific voltage that you use) by the amount of time to compare. I like the silicone panel idea. Might have to give that a try.

My solar oven was home made. A new one in progress. Slate tiles are just flat rocks. Made of slate:) I cooked in cast iron which also helped. Took a little longer to heat up but it really held the heat good.
 
Mart Hale
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Update.

I have returned to this setup as I don't have the off gassing I did with the solar vacuum tube with the silicon heater, so this is the best way for me to use the silicon heater.


Yesterday I hooked up 360 watts of solar power to the 240 watt heating pad and I got water to 160 degrees   ( about 18 cups of water ).      This was for a part day of solar heating.   

The next day - today-  it is now 10 AM and the water is at 110 degrees  the thermal cooker really holds the heat!  

Now I see a new application for this,   If I get the water 212 degrees   the next day I have 180 degree water,   Then I could pour this water into a solar shower bag and I now can have a free hot shower ( from the cost of the solar panels + thermal cooker + silicon heater )   or at least I will be getting the cost of my investment back.

I would mix cold water with the hot water to get the temp down to 110 degrees F.


Another idea hit me,    If I have water at 212 degrees I could put inside of this a bread pan and bake bread using the stored heat of the water.    I would put the bread pan right above the water line.


I am also considering testing putting bread in the cooker and trying to bake using no water, or perhaps I could put a round stone inside that would also serve as thermal mass inside the thermal cooker.

I love experimenting!
 
Mart Hale
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I have been letting this run with 1 gal of water in the pot with solar panels, the first day it hit 170 degrees,  today it hit 200 degrees.     So I am thinking with 3/4 of a gallon I could get this to boil each day and I could use this to boil eggs as long as it is sunny, or use it for showers or to fill hot water bottles.

So each day the heat from the previous day is still in the cooker, and it starts at a higher temp than the day before and gets hotter.


I am thinking that if I put cooking oil in this that I could have it reach over 300 degree given enough time.

 
Mike Barkley
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I would suggest NOT mixing cold water to cool it down. That is wasted energy. Waiting until it cools on it's own seems much more efficient, especially in winter.
 
Mart Hale
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Mike Barkley wrote:I would suggest NOT mixing cold water to cool it down. That is wasted energy. Waiting until it cools on it's own seems much more efficient, especially in winter.




Actually if you think about it mixing with cold water so that the cold water is raised up to a good temp   is better than letting it cool as letting it cool is wasted energy as you have done nothing with the energy but waited for it to be lost,   if you use that energy to raise the temp of cold water to just right temp for a shower then you have gained a longer shower as you have more volume of water to take a good shower with.
 
Mike Barkley
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letting it cool is wasted energy as you have done nothing with the energy but waited for it to be lost,  



My thinking was that it would be warming the air inside the house.
 
Mart Hale
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Solar experiment combining heat retention and silicon heater in a heat retention pan. The water in the pot is 108 degrees F from yesterday high of 190. I have cooked eggs with this setup, knowing the exact amount of water this heater can bring up past 190 degrees means I know now when I can cook with this. The next addition is to put this inside a chest freezer with blankets around the outside of the pot, I am most curious to see how much longer the heat will hold in this setup.

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Mart Hale
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I have boiled eggs with this solar thermo cooker and love it when I get results! :-)

Onto the next stage I am now testing cooking bread in this setup.       Yesterday I removed a few cups of water leaving only like 3 cups of water in the container,  the results was that now it reaches a higher temp faster,  the bread did not finish cooking yesterday so after keeping it in the fridge I am trying to finish cooking the bread today.

What I have learned with this is since the water is getting very hot it is creating much steam and the water drips back down on the bread.      I think I will put a small plate over the bread to stop this,  I have also managed to get my usb temp sensor working Go!temp,  so I am now logging temps with this so I will have an accurate measurement of cooking temps.     This will equip me to know how long I can safely cook with a given volume of water in the cooker.

 
Mart Hale
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A question that comes to my mind is this.

What would happen if I was to put gallon jugs of water in the freezer?     Would they absorb the heat from my experiments and give the freezer a higher temp to start with the next day verses being filled with wool blankets?


The advantage I would think is that they indeed would store the heat, but that may be a down side if they are pulling heat away from my food.     I imagine there would be an ideal amount of thermal mass  for this setup.

This is the exact question I am looking at in building a cob oven, is how do I find the optimal amount of thermal mass as compared to insulation.
 
Mart Hale
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Power source 300 watts of solar and 250 watt silicon heater. I was able to bake bread today in my heat retention cooker. Temp got up to 190 degrees with 3/4 of an inch of water in bottom of pan. I let this cook for 4 hours but then clouds came in. Bread did not rise very well, but I would call it done. Added butter and honey, and I am happy
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