- Food and Cooking
Induction Cooking energy saver
Single burner Induction cooktop
Induction Cooking energy saver: Introduction
In Our Solar oven – essential part of our cooking hardware I discussed our sun oven and in How to build a solar stove our sun stove. We have been using both for a long time with considerable savings on our electric bill. However, if the sun is not shining, you have to fall back on either gas or electricity. We have an electric stove, but all electric stoves are heavy on energy consumption, so we got ourselves an induction cooktop to replace the electric hubs as often as possible and a magnificent halogen infrared glass bowl oven to replace the electric oven – both of which are more energy efficient than their electric and gas counterparts. This means a huge cut in energy consumption – as we have experienced over the past three years.
Coil beneath cooking zone
How does induction cooking work?
Everybody knows how a gas and electric stove work. In the case of an induction cooktop a powerful, high frequency electro magnet is the core beneath each cooking zone. This does not generate heat which is then transferred to the cooking vessel - the cooking vessel itself becomes the generator of the heat needed for cooking.
Induction cooking step-by-step
Let's have a look at how induction cooking really happens step-by-step.
1. When the power is turned on, a current is sent through a coil underneath the ceramic surface cooking zone and this produces a high-frequency electromagnetic field.
2. That field then penetrates the metal of the induction ready cooking vessel (see below) and then something very interesting happens: The magnetic field sets up (induces) a current in the form of a circulating ("loop") electric current ("eddy current"). Unlike the current sent into the coil, the induced current is low in voltage, but high in "volume" (amperage). This current flows through the bottom of the cooking vessel, which poses a massive electrical resistance to the current, resulting in the generation of instantaneous heat. Heat is also generated by another process called "hysteresis", which is the resistance of the ferrous material to the rapid changes in the magnetic field (oscillating) generated by the induction element.
3. The heat generated in the cooking vessel is transferred to the vessel's contents by conduction since the food in the pot is in direct contact with the hot pot.
4. By controlling the strength of the electromagnetic field, you can control the amount of heat being generated in the cooking vessel instantaneously. As soon as the vessel is removed from the cooking zone, or the power is turned off, heat generation stops immediately.
Process of induction illustrated
Different induction cooktops
Induction cookers can be organized into four categories: Single burners, two burners, four burners and hybrid induction cooktops. The first of the new generation of “zoneless” induction cooktops have now become available as well. These essentially make the entire surface of the unit into a cooking area: Sensors under the glass detect not only the presence of a pot or pan, but its size and placement as well – and then energize only those components directly under the cooking vessel.
The models representing these categories have been reviewed and compared in tables at inductioncookerprice.com.
An induction cooktop is just as good as the cookware you’re using. With the wrong cookware, either nothing will happen at all, or the performance will be poor.
The cooking vessel has to be "induction ready" - the bottom has to be magnetic AND electric conductive. If one feature is absent, no heat will be generated. All ferrous cooking vessels (cast iron and enamelled cast iron) and some stainless steel ones comply. Copper and aluminum are excellent conductors of electricity and heat, but are not magnetic, so cooking vessels made only from these elements are not suitable.
An easy test: If a magnet sticks to the bottom of the pan/pot, it will work just fine.
The best induction cookware is discussed at length at this website.
Pros and cons of Induction Cooking
Pros of induction cooking
1. Induction cooking is more energy-efficient than either a traditional electric hub or gas stove. According to the U.S. Department of Energy the typical efficiency of induction cooktops is 84% (other reports say 90%). Most of the wasted energy goes into cooling the electronics of the cooktop. The efficiency for a smooth-top non-induction electrical unit is said to be 71%, while that of gas cooktops is 38 - 40%. (Source). (Also see Cooktop Comparison: Gas, Electric and Induction.)
2. Speed: An induction cooker is considerably faster than traditional electric cooking and compares favourably to gas cooktop cooking.
3. Safety: Induction cooktops are safer than any other form of cooking. Since heat is being generated by an induced electric current, the unit can detect whether cookware is present (or whether its contents have boiled dry) by monitoring how much power is being absorbed. So, no heat will be generated if there’s no cooking vessel on the cooking zone, even though the setting might be set at maximum. The heat is only generated in the cooking vessel, so you don’t get a red-hot cooking zone when you remove the cooking vessel, even though your setting is set at maximum. The area below the pot gets hot only from its contact with the pot. As a matter of fact, you can put a newspaper/cloth beneath the pot and it won't be set on fire, even though the content inside the pot is boiling.
Cons of induction cooking
Unfortunately, most of your cookware will not work on an induction cooktop. It only works with “induction-ready” cookware, as discussed above.