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| 11/22 |
| 2006/3/6-8 [Science/Electric, Science/GlobalWarming] UID:42104 Activity:nil |
3/6 I went to the Home Depot appliance section today and I saw this
really cool futuristic looking stove with completely flat
ceramic surface which I presume makes cleaning a breeze! It
looked so beautiful I fell in love with it immediately. I'm
wondering how they work and if they work well. How do they
transfer heat from ceramic to the pots? Are these what they
call the "eddi-current induction" cooker? How well do they
work? Thanks.
\_ i have one of these in my apartment. it is surprisingly
difficult to clean... if anything spills over, it gets
burnt and you have to scrape it off. burnt up stuff can
really stick of ceramic. also, the flat surface makes dirt
really obvious, so i think you end up doing more work to
keep it looking respectable. i think it works as well as
any electric stove i've used [nothing spectacular in terms
of heating stuff up].
p.s. 80 columns is teh standard.
\_ They're very easy to clean--you usually get a metal scraper
with it (do _not_ use abrasives of any kind.) As counter-
intuitive as it seems, just scrape anything off. The poster
below isn't entirely correct; glass-ceramic stovetops do heat
up a lot faster than regular electric coils (I have one at
home) and I don't get the impression they use more energy,
although I'd be at a loss to tell you how it works. I think
it has to do with the heat conductivity of the cooktop. -John
\_ It heats up faster b/c the coil underneath can be more
delicate and thus more responsive (the kind you set pans off
have to be more rugged)
\_ http://en.wikipedia.org/wiki/Stove#Gas_and_electric_stoves
Look for the part about "glass-ceramic"
\_ Basically it's just an ordinary electric coil under a glass top.
\_ That is right. Induction cooking has not caught on in the US.
Like the American car mentality, primitive stoves are "good
enough."
\_ Not sure which one you were looking at, but there are two possible
technologies you were looking at. 1) electric under the ceramic top-
has the same disadvantages as normal electric, no instant heat, more
costly energy 2) magnetic induction- only works with certain pan
materials (i.e. iron). There are numerous others gotchas, but as cool
as flat-tops look, I think gastops are still the best of existing
technologies (weird in the year 2006).
technologies you were looking at. 1) electric under the ceramic
top- has the same disadvantages as normal electric, no instant heat,
more costly energy 2) magnetic induction- only works with certain
pan materials (i.e. iron). There are numerous others gotchas, but
as cool as flat-tops look, I think gastops are still the best of
existing technologies (weird in the year 2006).
\_ If you saw it at Home Depot, or in the United States for that matter
then 99% of the time it is NOT an induction stove. Induction stoves
are very popular in Asia like Japan and have the electric->heat
efficiency of 80-90% (depending on manufacturer and the type of
pot you use). They are completely cool to touch and only heat up
the pot directly to reach that efficiency. What this means is
that you can't use aluminum or glass on top to heat things up.
You need to use special pots with thick irons to reach high
elec->heat efficiency. If you go to Marukai or high end Asian
markets (not Ranch 99) in JapanTown, you'll find special pots that
say in kanji, "Thick Bottom" and bold letters like CH and IH meaning
those pots are specially designed for Induction Heating. The bottom
is usually at least 5mm with thick iron, while aluminum or something
else wrap around it. I have never seen induction stoves or induction
pots sold in the US. The exception would be those high-end web sites
that tailor to professional chefs. I guess when energy is so cheap
and plentiful, who cares about stove efficiency?
\_ 5 cm thick?! You think this is an efficient way to cook? Do you
have any idea how much energy it takes to dig up that much iron,
refine it, make your 5cm thick pots and pans from it, transport
to the stores for you to buy, etc? To save how much energy on
the cooking side of the equation? Not to mention the damage
caused to the environment with all the mining operations required
to dig up the iron in the first place. And then I'd have what?
An extra 5 lbs? 10 lbs? more? of pan to lug around to clean,
move, etc. At least it would be too heavy to make a decent
weapon.
\_ my bad I mean 5mm. Wow someone in the US understands the
metric system. I'm impressed. -op
\_ wow, ok, nevermind then. I had this image of this giant
unmovable object that needed to be cleaned on the spot
because it would be impossible to move to a sink or put
in any sort of dish washer. My uncle had an old style
iron pan I could barely move (I was a kid) which wasn't
anything like 5cm. Probably about the 5mm you meant but
still very heavy.
\_ Where can I get more info on this inductive heating
technology? I saw a Zojirushi rice cooker with inductive
heating technology, but wasn't sure what it is. How safe
is it? You said iron, is it iron coated with Teflon?
\_ Why does it have to be coated with teflon?
\_ Rice cookers pots are usually non-stick. What else
would it be if not teflon?
\_ I don't know what kind of fancy cooker you've got,
but the ones I've seen are aluminum.
\_ http://www.jetro.go.jp/en/market/trend/topic/2004_11_mtm.html
If you have a lot of cash buy this one:
http://biccamera.com/bicbic/jsp/w/catalog/detail.jsp?PRODUCT_ID=0010055457
Don't get those American/China-made knockoffs that are less
than 2000W |
| 11/22 |
|
| en.wikipedia.org/wiki/Stove#Gas_and_electric_stoves edit Modern stove features Modern stoves are typically considered a basic appliance in homes in developed nations. Along with the refrigerator, a stove is usually found in the kitchen. Many modern stoves typically have from three to eight burners or plates of various sizes and power levels; and knobs, for controlling the heat of the burners and the oven. The control knobs may be located on the backsplash, on the cooktop, or on the upper part of the front of the stove. Middle- to high-end models also may feature locking mechanisms for the oven door; Fahrenheit) and reduce accumulated food spills to ash or a catalytic oven lining which aids in burning off spills; Many can even accommodate automatically raising and lowering the oven temperature to preset levels at preset times. Attempts were made to enclose the fire to make better use of the heat that it generated and thus reduce the wood consumption. A first step was the fire chamber: the fire was enclosed on three sides by brick-and-mortar walls and covered by an iron plate. edit Wood stoves (metal stoves, masonry stoves) Although a good source of light before lamps, an open fireplace is a very inefficient form of heat for two reasons. First, in order to prevent air, and therefore smoke, from spilling back into the room you need a large updraft pulling air (and therefore heat) out the chimney. This both pulls heat away and pulls air from the rest of the house into the fire and then up the chimney. A fireplace consumes 200 to 600 cubic feet of air per minute, more for a very large fire. A mostly closed off fireplace, for example a modern fireplace with glass doors closed will use 50-150 cubic feet per minute. High airflow creates a draft which pulls heated air out of the house to be replaced with cold air leaking in from the outside. Second, in an open fire some of the combustible gas coming off the wood escapes does not ignite and is lost. It had a labyrinthine path for hot exhaust gases to escape, thus allowing heat to enter the room instead of going up the chimney. The Franklin stove, however, was designed for heating, not for cooking. Rumford stove used one fire to heat several pots that were also hung into holes so that they could be heated from the sides, too. It was even possible to regulate the heat individually for each hole. His stove was designed for large canteen or castle kitchens, though. It would take another 30 years until the technology had been refined and the size of the iron stove been reduced enough for domestic use. cooking machines with flue pipes connected to the chimney, oven holes, and installations for heating water. The originally open holes into which the pots were hung were now covered with concentric iron rings on which the pots were placed. Depending on the size of the pot or the heat needed, one could remove the inner rings. By controlling the inflow of air to allow only what a fire needs to burn, metal stoves reduce the consumption of air to a mere 15-30 cubic feet per minute (this figure is for a modern stoves. All metal stoves operate on the principle of controlled air flow but their consumption will vary). Modern wood stoves also increase the completeness of combustion. More expensive stoves use a catalytic converter which causes the gas and smoke particles not actually burned to combust. Other models use a design that includes firebox insulation, a large baffle to produce a longer, hotter gas flow path and pre-heating the air prior to its entering the combustion chamber. masonry heater is designed to allow complete combustion by burning fuels at full-temperature with no restriction of air inflow. Because the firebox is masonry (not metal) the burn temperature can increase to the point where secondary and complete combustion of the fuel takes place. These heaters capture most of the heat from the combustion and exhaust through an extended system of flues inside a large thermal mass before the exhaust is vented to the outside air. A properly fired masonry heater has little or no particulate pollution in the exhaust and does not contribute to the buildup of creosote in the heater flues or the chimney. Due to its large thermal mass the captured heat is radiated over long periods of time without the need of constant firing, and the surface temperature is generally not dangerous to touch. In the US, the EPA created stricter emissions standards in the late 1980s. Maximum smoke output is limited to 75 grams per hour and some stoves achieve as little as 1 to 4 grams per hour. Put differently, this is roughly 90% less smoke than older stoves, which equates to nearly zero visible smoke from the chimney. This is largely achieved through causing the most possible material to combust, which results in a net efficiency of 60 to 70% as contrasted to zero to 30% for a fireplace. The main factor for this delay was the slow growth of the gas pipe network. The first gas stoves were rather unwieldy, but soon the oven was integrated into the base and the size reduced to fit in better with the rest of the kitchen furniture. But like the gas stove, the electrical stove had a slow start, partly due to the unstable technology, and partly because first cities and town needed to be electrified. coils which heated iron hotplates, on top of which the pots were placed. Though the technology is slowly fading into obsolecence, coil ranges still provide the best durability out of all electric cooktop implementations. Because of its physical characteristics, the cooktop heats quicker, there is less afterheat, and only the plate heats up while the adjacent surface remains cool. Also, these cooktops have a smooth surface and are thus easier to clean, but they only work with flat-bottomed cookware and are markedly more expensive. convection oven, a stream of hot air is used for heating food instead of the heat produced by coils directly as in a conventional electrical oven. Gas and electric stoves are the most common today in western countries. Both are equally mature and safe, and the choice between the two is largely a matter of personal preference and preexisting utility outlets: if a house has no gas supply, adding one just to be able to run a gas stove is an expensive endeavour. chefs often prefer gas cooktops, for they allow them to control the heat more finely and more quickly. On the other hand, chefs often prefer electric ovens because they tend to heat food more evenly. Today's major brands offer both gas and electric stoves, and many also offer dual-fuel stoves combining gas cooktops and electric ovens. Metal ovens and stoves, throughout history, have one thing in common, they will burn the person who comes in contact with their hot metal surfaces, for instance, the oven rack's front edge. Devices to protect the hands, such as oven gloves, have been developed, but need to be used consistently, to be effective; Recently, a device has been invented by Burt Shulman of Wappingers Falls, NY, called the Cool Touch Oven Rack Guard, which is a fabric strip that attaches along the front edge of the oven rack and stays in the oven. edit Modern corn, pellet or biofuel stove A corn stove is a type of pellet stove which is a type of biofuel stove. The shelled dry kernel of corn, also called a corn pellet, creates as much heat as a wood pellet but generates more ash. "Corn pellet stoves and wood pellet stoves look the same from the outside. Since they are highly efficient, they don't need a chimney; instead they can be vented outdoors by a four-inch pipe through an outside wall and so can be located in any room in the home." Encyclopedia of Alternative Energy A pellet stove uses small, biological fuel pellets which are renewable and very clean-burning. Home heating using a pellet stove is an alternative currently used throughout the world, with rapid growth in Europe. The pellets are made of renewable material -- typically wood sawdust or off-cuts. There are currently more than half a million homes in North America using pellet stoves for heat, and probably a similar number in Europe. The pellet stove typically uses a feed screw to transfer pellets from a storage hopper to a combustion ch... |
| www.jetro.go.jp/en/market/trend/topic/2004_11_mtm.html Business Topics Trends and Topics Business Topics November 17, 2004 Demand for Induction Cooking Heats Up Induction cooking ranges are experiencing brisk sales in Japan as consumers learn about the benefits of these modern appliances. The trend is part of a broader consumer shift from gas appliances to electrical appliances due to advantages including increased safety, lower cost and superior function. Induction ranges use a magnetic field to generate whirling flows of electricity, known as eddy currents, in the bottom of cookware. Heat is generated when these currents meet the electrical resistance of the cookware. In addition to ranges, induction cooking appliances include products such as rice cookers, grills and pressure cookers. Several other kinds of electric ranges also exist, including tubular heating, radiant heating and halogen heating. But generally speaking, electric ranges have not penetrated the Japanese market successfully because they require 200V wiring, which is not common in Japanese homes. At present, the main heating sources for cooking are natural ("city") gas and LPG, but since induction ranges generate power equal to that of gas ranges, they are expected to help accelerate the popularization of 200V wiring. The surface of an induction range is made of a hard ceramic material, onto which cookware is placed. When electric current passes through coils underneath the surface, a magnetic field produces an eddy current in the cookware. The cookware's internal resistance against these eddy currents produces heat. In other words, the heat is generated in the cookware, not on the range itself. One might think that since there is no flame, like in a gas range, heating would take longer, but heating is actually very fast because it begins the moment the range is turned on. Compared with the 40% to 50% heating efficiency of city gas and LPG stoves, induction ranges are 80% to 90% efficient, meaning that only low amounts of energy are lost. Compatible with Aluminum and Copper Cookware Induction ranges come in low and high-frequency varieties. Low-frequency models use 50 Hz/60 Hz power supply (varies by region in Japan) and their structure is simple, but they are noisier and less efficient than high-frequency models. Furthermore, special cookware must be used, and while the range is on, the cookware cannot be moved because it sticks to the range's surface by magnetic force. High-frequency ranges use an inverter to transform the 50 Hz/60 Hz frequency up between 22 kHz and 32 kHz. Their structure is complex, but regular cookware made of enamel-coated iron, stainless steel and other materials can be used with these ranges. Unlike low-frequency ranges, they produce little noise and the cookware does not stick to the surface due to magnetic force. For these reasons, the high-frequency variety has gone mainstream. High-frequency ranges that accept aluminum and copper cookware have also appeared. The low electrical resistance of such cookware prevented them from being used with earlier induction ranges. But then it was discovered that resistance increases when an electric current is focused on the surface of the cookware and the current's path is narrowed. The solution, therefore, was to increase the power of the coils. Induction ranges can be used to prepare a wide variety of dishes, including fried foods, steaks, stews and grilled fish. Cleanup is a snap and, since there is no open flame, heating is safe, making them ideal for homes with senior citizens or small children. No gas or open flame also helps to minimize danger in the event of an earthquake. Companies such as Toshiba, Mitsubishi Electric, Sharp, Matsushita Electric and Hitachi Home & Life Solutions are the main suppliers of induction ranges. In addition to appliance manufacturers and power utilities, housing and condominium builders are promoting induction ranges as sales features for their properties. Nearly 600,000 Units Sold in 2003 So how popular have induction ranges become? According to figures from the Ministry of Economy, Trade and Industry (METI), some 21 million induction ranges (mostly table-top variety) were manufactured in Japan in the 12 years through 2001. Roughly speaking, this means 45% of all Japanese households have an induction range, if you assume all were sold domestically and there is one range per household. The production figures for 2000 and 2001 were 210,000 and 234,000 units, respectively, and the factory-gate price per unit was 18,000 yen in 2000. In 2001, however, the price skyrocketed to just under 30,000 yen due to the introduction of built-in units. Starting from 2002, METI stopped collecting figures for this category and from 2004 began collecting production figures for all cooking ranges, including non-induction ranges. The data specifies built-in and standalone models, but not tabletop models. The retail price per unit was around 150,000 to 250,000 yen (about US$2,300),excluding consumption tax and installation fees. In 2002, the Japan Electrical Manufacturers' Association (JEMA) started collecting production figures for cooking ranges (same category as the METI) based on retailer shipments (please see graph). The demand for gas cooking stoves in Japan is a little less than 5 million units a year. The majority are stoves with two or more burners, and they compete with built-in and standalone induction ranges. The scramble for a piece of the pie between appliance manufacturers, electric power companies, gas companies, home builders, and other companies is about to intensify in the market for cooking appliances and energy targeting 47 million households. Furthermore, since the groundwork has already been laid in the US and European markets with 200V outlets, we should expect that built-in and standalone induction cooking ranges, which have been forged in the Japanese market, will become a major export product. |
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