Induction cooking in the off grid home?

Generally speaking it has been taboo to employ solar energy for heating water and cooking food. Energy was transferred to the water or food via electrical resistance and was not efficient.

Enter affordable induction cooking: https://en.wikipedia.org/wiki/Induction_heating "An important feature of the induction heating process is that the heat is generated inside the object itself, instead of by an external heat source via heat conduction."

I may not be ready to use induction cooking for dinner but I suspect that it makes sense for breakfast and lunch. Wish I knew how much more efficient induction cooking is than "resistance" cooking. My guess would be ~75% more efficient. It is fast. It is safe...the "heating" surface does not even get hot.

So far my experience is in making a fast cup of coffee. Perhaps we may stir a debate of the pros (many) and cons (requires iron/steel cookware).


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Comments

  • animatt
    animatt Solar Expert Posts: 295 ✭✭✭
    edited September 2016 #2
    Cooktop will get hot.  But not from the cooktop side.  The thing being heated will loss some heat below and heat the cooktop. It can and does get hot.  If you put a thin paper towel on the cooktop under the cooking vessel you can reduce heat on the cooktop. Protect cooktop from scratches from heavy cookware,  and possibly speed up cleanup as grease will splatter onto paper towel vs cooking surface. 

    I think there are efficiency numbers out there of induction vs gas and induction vs resistance cooking. Not sure where I saw them. And if they were from a biased source or not.

    Obviously resistance cooking is not as efficient as induction cooking.

    But induction cooking is not as efficient as an electric water heater(resistance kind).  Difference being water heating takes much more energy than meal cooking. Just something to think about.
    The electronics in the cooktop use some energy as well as heat does radiate from cooking vessel outwards as well as inwards .

    And it a hot debate we have had before.  I remember a specific one from a few years back. I would imagine most of the regulars would as well
    http://forum.solar-electric.com/discussion/19736/induction-cooker/p1
    Can't remember how much useful info was there.
    Also one clarification.   Induction cooking heats the cooking vessel directly,  not the actual food. Just a clarification from your quote.


  • Photowhit
    Photowhit Solar Expert Posts: 6,002 ✭✭✭✭✭
    I use an induction burner pretty regularly. It's advantages are in speed, I can put a small amount of water in a pan to blanch some onions and turn the oven on and the water will boil inside of a minute! faster than a gas cooktop! But they use a good bit of energy on low I think the NuWave goes for a low of 800watts to a high of 1500 (maybe 1800 watts)

    But if you want to fry some eggs, it's pretty quick, I use a small 6" frying pan, mostly because the coil area of the 2 induction cooktop's I own are pretty small 5-6" so if you put a 9" pan on the outside edges will be cooler, relying on the metal to caray the heat to the outside. But cast iron works fine. I'll put the pan on and turn the oven on and grab a stick of butter out of the fridge, and turn around and apply it directly to the pan, which will be warm or hot depending on how slow you are. It will be hot by the time you drop the eggs on. then it's frying as normal.4-5 minutes and you're done.

    My old hot plate is 900-1000watts and would take a while to heat the pan...
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • jonr
    jonr Solar Expert Posts: 1,386 ✭✭✭✭
    Put a meter on various methods and measure the energy used to bring some water to a boil.

    I am available for custom hardware/firmware development

  • Raj174
    Raj174 Solar Expert Posts: 795 ✭✭✭✭
    I agree with Photowhit. I replaced a standard electric range about 3 years ago with a Maytag range with induction cooktop.
    I have found that boiling water for short periods of time for tea or blanching and cooking foods that cook quickly like eggs or grilled items are much more efficient in power use due to shorter cook times. I would also add that I believe the heat load produced by cooking a meal using 2 or 3 burners with induction cooking is maybe 15 or more percent less for the A/C to remove from the home environment.
    4480W PV, MNE175DR-TR, MN Classic 150, Outback Radian GS4048A, Mate3, 51.2V 360AH nominal LiFePO4, Kohler Pro 5.2E genset.
  • MGar
    MGar Registered Users Posts: 14 ✭✭
    They work great as long as you balance your L1 and L2, I can use 2 at same time each ~1000 watts
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Induction is great, as long as you have the power. I have a small induction hot plate.  
    An electric kettle is just a little more efficient, since it has no internal electronics that need a cooling fan, otherwise all the power in induction goes into heating the pan.  The pan re-radiates little power, compared to a electric coil or a gas burner where the heating element also heats the air in the room.
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  • Photowhit
    Photowhit Solar Expert Posts: 6,002 ✭✭✭✭✭
    edited September 2016 #8
    Just to your point of "...taboo to employ solar energy for heating water and cooking food."

    I use a variety of cooking items with solar, and have since I had a small 1000 watt array.

    I've use Foreman grills, the small ones use 600-760watts and heat and cook very fast, maybe 3-5 minutes to heat up, then cook chicken fillet's in 5 minutes and larger chicken breasts in 6-7 minutes, max.

    I'll often leave a crock pot going during sunny days, at 120 watts for the 2 quart and 200-300 watts for a 4-5 quart, this is electric, the way solar generates it, low and slow. They are thermostatically controlled so after a couple hours they do cycle on and off, want to help them add some insulation, like throw a hand towel over them (or aluminum foil)

    I use a couple rice cookers, a 300 watt 6-8 cup (cooked size) and a 3 cup cooked size at 200 watts. I'll often add a piece or 2 of shredded roasted chicken (sometimes done in the crock pots) and onions, garlic and end up with a prepared meal in about 30 minutes. The larger rice cooker has a steam tray so I can add fish or veggies.

    With my larger array I regularly run heavier loads on some days, Today I dehydrated 3 gallons of apples in a 600watt dehydrator for 9 hours.


    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • Johann
    Johann Solar Expert Posts: 245 ✭✭✭
    A electric frying pan and a nuwave should have about the same power consumption/loss.
    Either way, the pan itself is losing the heat.


  • Photowhit
    Photowhit Solar Expert Posts: 6,002 ✭✭✭✭✭
    edited September 2016 #10
    Johann said:
    A electric frying pan and a nuwave should have about the same power consumption/loss.
    Either way, the pan itself is losing the heat.



    No, the induction works in a very different manner, the induction cook top creates a varying magnetic field that heats the magnetic metal pan almost instantly, an electric pan will still require time to heat up. Once it is heated up, I would agree that he loss would be similar to a pure resistant load like an electric skillet, in fact an electric skillet might use less electric once heated.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • Photowhit
    Photowhit Solar Expert Posts: 6,002 ✭✭✭✭✭
    Oh I almost forgot about bread makers, some use as little as 400 watts and them mostly during the cooking cycle and that is thermostatically controlled.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.