Rice Cooker Eco-Hack

[Southcross]

I wonder... could it be possible to hack a coffee maker in a similar fashion? a "normal" coffee maker can consume 900-1000w while its in initial warmup (then levels off to an average of about 150-200w between heating element on and off time). Also, insulating a glass carafe would be interesting.

[AC_Hacker]

Originally Posted by Southcross

I wonder... could it be possible to hack a coffee maker in a similar fashion? a "normal" coffee maker can consume 900-1000w while its in initial warmup (then levels off to an average of about 150-200w between heating element on and off time). Also, insulating a glass carafe would be interesting.

My thinking when I did the hack was that if I could prevent heat from radiating away, that I could reduce the amount of energy needed to cook the rice.

The rice cooker is already designed with a heating element of the properr wattage that will provide a medium simmer. The simmer will continue until enough water has been boiled off that it will no longer limit the temperature in the pot to 212 degrees. Then, when the temperature rises, te power is cut. So there is a time-temperature limit built into the design.

I figured if I insulated the pot well, it would retain heat and I could reduce the power by half with a diode, the 212 temperature level would still be reached and cooking would happen with a lower power. It worled out that way, but the cooking time takes a bit longer.

It will be interesting to see what you come up with regarding your coffee pot hack.

BTW, I think that thermally insulated carafs are already included in some coffee makers.

Regards,

-AC_Hacker

[Daox]

Have you figured out how much energy your hack has saved?

[AC_Hacker]

Originally Posted by Daox

Have you figured out how much energy your hack has saved?

Great question.

I haven't yet. I'll need to pull out the insulation and jump past the diode.

It needs to be done.

-AC_Hacker

[Christ]

Some coffee makers come with stainless steel carafes that have fiberglass or other insulation in them. Some also, apparently, are vacuum sealed canteen style carafes.

When the glass one broke on my Father's coffee pot, I stuck a metal coffee can with a bend in the lip under the dripper. Worked fine until he got a new coffee maker for Christmas from a relative.

[Daox]

Bumping this because I wanna know if it worked.

[AC_Hacker]

Originally Posted by Daox

Have you measured total energy usage with and without the modifications? That would be very interesting to see.

I noticed that the rice was well-cooked after the eco-hack, maybe too well...

As previously explained, the mechanism of timing the rice cooker's cook cycle relies on boiling off the cooking water. When the water has been absorbed by the rice and the rest boiled off, the temperature rises and the cycle is ended.

For brown rice, the normal water-to-rice ratio is about 2.5 to 1.

The Eco-Hack added insulation which reduced heat loss, and it reduced the power being used by half by using a diode. After this has been done, the time for the cooker to reach cooking temperature is longer than an unmodified cooker. Once the temperature is reached, the cooker simmers the rice & water at a slightly less vigorous level, but 212F is still 212F.

So, cooking took longer, and the rice was over-cooked, not burned, but too soft almost mushy.

Finally, it dawned on me that I could reduce the cooking time by reducing the amount of water being used. After several trials, I settled on a water-to-rice ratio of about 1.8 to 1.

So, to summarize, an unmodified cooker uses enough power to cause the absorbtion and boiling off of 2.5 cups of water per cup of rice. While a modified cooker uses enough power to cause the absorbtion and boiling off of 1.8 cups of water per cup of rice. This would imply a reduction in power used by at least 30%. And, since I have not yet tried a before and after power reading, the actual efficiency due to the retaining of heat by the insulation will surely be higher.

Originally Posted by Daox

Also, how did you disable the warming feature?

If you look at this post, in the second photo you will see a pointer bearing the labeled "remove warm wire". When you remove that wire, put heat shrink tube over the wire and tuck it out of harm's and heat's way. That's all it takes.

Regards,

-AC_Hacker

[Solar Mike]

Interesting experiment you have going there, I use a slow cooker often enough to think about modding it, however one thing they have in common is the closed air gap surrounding the heated bits, an air gap in its self is a good insulator, packing this area with fiberglass will stop air convection currents?, you could equally leave out the insulation and stick some shiny foil to the inside of the outer bowl, to reflect the heat back inside.

Cheers
Mike

[AC_Hacker]

Originally Posted by Solar Mike

Interesting experiment you have going there, I use a slow cooker often enough to think about modding it, however one thing they have in common is the closed air gap surrounding the heated bits, an air gap in its self is a good insulator, packing this area with fiberglass will stop air convection currents?, you could equally leave out the insulation and stick some shiny foil to the inside of the outer bowl, to reflect the heat back inside.

This could work, I don't know if it would work better than insulation or if the cooker would work better with a radiant barrier inside the heated area AND insulation outside the heated area.

One thing that fascinates me about the rice cooker is the clever magnetic switch. It's not only a convenience feature but also a safety feature.

I don't think that magnetic switches are used in slow cookers... you don't have the same cooking conditions as when cooking rice.

But using fireproof insulation in a slow cooker would improve efficiency. The diode trick might work in this case, also a high-power dimmer switch would do it too, as would a short-burst cooking cycle combined with very good insulation, which would allow the food to continue cooking long after the power was removed.

The fireless cookery system required that a long-cooking soup, stew, or porridge be set on to cook very early in the day. When it was roughly half-cooked (and presumably synchronized with the departure time of our hypothetical farmer ), it was placed—food, pot, cover and all—into a tightly closed container and buried within an insulated container, to be carried along for eventual consumption. During this time, the food continued to cook via its own residual heat, and could be expected to be ready a few hours later when needed.

...more here...

...and still more here...

Roll up your sleeves my friend, there's efficiency to be found!

Best Regards,

-AC_Hacker

[Clev]

How long does it take to cook, and how much is cooked? I can do a little over four cups of rice in a microwave rice pot in 18 minutes @ 1,000 watts, or about 300Wh.