Microwave vs stove - Heating water

[PottedMeat]

There is really only one thing wrong with Fleabag, he believes he knows it all. And he will die defending that belief.

We've drifted from the original question, but why pose a question when it's clear you already have an answer?

and we have every fleabag thread ever.

 

[Cogman]

Well it's about the fact that when you use a stove, you heat the heating element, which heats air which heats the metal pot which heats the water... A lot of waste there.. The point I was trying to make with the OP was does Ohms law take precedence over the conductive losses of using a pot and pan on an electric burner or not. Pot and pans at 220V vs microwave at 120v but having all of the energy being directed at the food with some energy lost due to the food radiating the heat into the container. The container in a microwave is not directly heated like it is on a stove.

I was referring to an electric kettle, not a stove.

For a stove, it depends on the stove. If you have a glass top stove like I have, and the pot completely covers the element, then the efficiency is going to be fairly high, regardless of if there is air pockets or not. An open heating element isn't going to have the same guarantee. The non-scientific test that you can do to see how efficient your stove top is, is to just hover your hand over the element with a pot of cold water on it. If you feel heat, that's energy being wasted.

That being said. Pretty much all metal has a fairly good level of thermal conductivity. So, even though some energy is being lost due to heating air (Which really has pretty terrible thermal conductivity) Most of it will be delivered straight into the pot.

As for the 120V and 220V thing. I really have no clue what you are trying to get at there. Voltage really doesn't matter when talking energy efficiencies of giant resistors (Unless you are talking about power loss is delivery, in which case 220V has a higher efficiency. However, the lines in your house run probably, at most, 1ohm. So power lost in your home cables is going to be minuscule and not worth mentioning.)

As for the microwave being more efficient. It depends. How much energy is being absorbed by the metal (when the microwave light misses the water), How well tuned is your microwave? IE how much is being produced at 2.4 GHz, vs 2.3GHz. All these things are going to affect the efficiency of the microwave.

 

[Bignate603]

As for the 120V and 220V thing. I really have no clue what you are trying to get at there. Voltage really doesn't matter when talking energy efficiencies of giant resistors (Unless you are talking about power loss is delivery, in which case 220V has a higher efficiency. However, the lines in your house run probably, at most, 1ohm. So power lost in your home cables is going to be minuscule and not worth mentioning.)

My thoughts exactly. Compared to the losses getting from the power plant to the last step down transformer out on the pole near your house the losses due to using 120 volt instead of 220 volt are tiny, especially when you're just looking at power needed to run a single burner. You'd have a bigger change on the overall efficiency if you just put a cover on the food you're heating.

Like a typical fleabag thread he's latched onto one shred of a fact and ignores all others.

If he really cared about saving power so much that the difference between a microwave and stove mattered he would never even turn on his computer. The amount of time he spends on here uses way more electricity than any difference between those two methods of heating food.

 

[alkemyst]

No matter how hard you mash those two pieces of metal together, you're still sitting on a bed of air. If you want them to actually be touching, you either have to smelt them together or add a thermally conductive paste. There is a reason why computer processors use a thermal paste when attaching a heatsink.

This is ATOT we all lap our pots and pans and heating elements.

AS5 or go home.

 

[zinfamous]

dang. and here I just assumed this thread ran out of steam last week.


never underestimate the need of one resident troll to increase his water heating-->steam potential.

 

[geno]

dang. and here I just assumed this thread ran out of steam last week.


never underestimate the need of one resident troll to increase his water heating-->steam potential.

It didn't run out of steam because it's being powered by an electric kettle and they are 100% efficient.

 

[jeanclaude]

If I had it, I would make you people beg me to give it to you.. Unfortunately I can't link to it because I read it then forgot where I got it from.. I've learned my lesson and have since then written down the URLs of where I get this information.

No matter how hard you mash those two pieces of metal together, you're still sitting on a bed of air. If you want them to actually be touching, you either have to smelt them together or add a thermally conductive paste. There is a reason why computer processors use a thermal paste when attaching a heatsink.

It has everything to do with voltage.. How do you think the electricity gets to your house? If you pump electricity through the house at a lower voltage, it is less efficient than pumping it through at a higher voltage..
2X 120V @ 10a each is better than 1X 120V @ 20a. The more you step down the voltage, the more is lost in the wiring and in the transformer itself. There is a reason why your high power consumption appliances run off 220V while everything is 120V.

Fleabag always delivers.
Proof postive that a little information and a complete lack of ratiocination skills is a dangerous mix.
Oh - and access to the Internet.
Bad bad combination.

 

[Kirby]

fleabag is the offspring of a retard frog-squirrel that butt fucked a monkey-fish-frog.

 

[darkswordsman17]

fleabag is the offspring of a retard frog-squirrel that butt fucked a monkey-fish-frog.

Which one showed him how to warm up, a truck at Lake Tahoe, in winter?

 

[canis]

..

 

[canis]

..

 

[fleabag]

This is ATOT we all lap our pots and pans and heating elements.

AS5 or go home.

That's right!

 

[fleabag]

I was referring to an electric kettle, not a stove.

For a stove, it depends on the stove. If you have a glass top stove like I have, and the pot completely covers the element, then the efficiency is going to be fairly high, regardless of if there is air pockets or not. An open heating element isn't going to have the same guarantee. The non-scientific test that you can do to see how efficient your stove top is, is to just hover your hand over the element with a pot of cold water on it. If you feel heat, that's energy being wasted.

"vast majority" sure but there are still some losses and so to say it's 100% efficient is a misnomer because there are losses from transferring the energy all the way from the powerplant directly into your food. Also when people proclaim such crap as "electric heating is 100% efficient", they never account for the energy losses not only in generating the electricity at the powerplant but also the losses transmitting it to the house.

That being said. Pretty much all metal has a fairly good level of thermal conductivity. So, even though some energy is being lost due to heating air (Which really has pretty terrible thermal conductivity) Most of it will be delivered straight into the pot.

As for the 120V and 220V thing. I really have no clue what you are trying to get at there. Voltage really doesn't matter when talking energy efficiencies of giant resistors (Unless you are talking about power loss is delivery, in which case 220V has a higher efficiency. However, the lines in your house run probably, at most, 1ohm. So power lost in your home cables is going to be minuscule and not worth mentioning.)

As for the microwave being more efficient. It depends. How much energy is being absorbed by the metal (when the microwave light misses the water), How well tuned is your microwave? IE how much is being produced at 2.4 GHz, vs 2.3GHz. All these things are going to affect the efficiency of the microwave.

I know, this is what I wanted to discuss when I started this thread...

 

[DrPizza]

If I had it, I would make you people beg me to give it to you.. Unfortunately I can't link to it because I read it then forgot where I got it from.. I've learned my lesson and have since then written down the URLs of where I get this information.

And you probably can't find it again because if it really existed in the first place, it's been removed as a hoax or as faked research. There are plenty of videos on youtube of drunks using a fairly standard compressor to inflate their tires until they burst. They burst at FAR lower than 600psi.

No matter how hard you mash those two pieces of metal together, you're still sitting on a bed of air. If you want them to actually be touching, you either have to smelt them together or add a thermally conductive paste. There is a reason why computer processors use a thermal paste when attaching a heatsink.

Not quite. I'm not even sure you're close. If true, explain different coefficients of friction. Liquids can change to the shape of a vessel more easily. Putting a thin layer between two layers of solid enables you to ensure that much closer to 100% of the surface is in contact.

It has everything to do with voltage.. How do you think the electricity gets to your house? If you pump electricity through the house at a lower voltage, it is less efficient than pumping it through at a higher voltage..
2X 120V @ 10a each is better than 1X 120V @ 20a. The more you step down the voltage, the more is lost in the wiring and in the transformer itself. There is a reason why your high power consumption appliances run off 220V while everything is 120V.

Actually, the reason is that the high power consumption would require too thick of a copper wire to safely provide the necessary current. Your calculation above - 2x 120V @10A is better than 1x 120V @20A is only true if the conductors are of the same gauge, in which case, you'll have twice as much loss in the 20A circuit. And as most (I can't recall seeing otherwise) 120V household circuits are either 12 gauge or 14 gauge, while most 240V circuits are a minimum of 10gauge, you're especially correct. P.S., I'd take off full credit if you were in my physics class and used lower case A for amperes.

Nonetheless, 12AWG wire would have approximately 50% more voltage drop over a given length of circuit. Using my house as an example, since the length of the line from the breaker box to the kitchen appliances will be different from home to home, for my 240V ovens, I see a voltage drop of... well, I don't. It's a fraction of a volt. Ditto for my microwave which despite having almost 10 extra feet of wiring (why the hell can't you hard wire microwaves? Why are they on a plug? If my microwave is on fire, I sure as hell am not reaching OVER it into the cabinet to unplug the microwave; sigh, but I digress) the voltage drop is again, negligible. Sure, one of them is twice as much as the other, but that's under YOUR assumption that the wiring all has the same current in it. It doesn't. That's the point everyone else is making that it's the watts, not the voltage.

Negligible: http://www.epanorama.net/documents/wiring/wire_resistance.html
Just a site at random. 12 gauge wire has a resistance of 0.00187 ohms per foot. My kitchens appliances are, at the most, 25 feet of wire from the breaker box. Go ahead and calculate the watts I "lose" to the wire... it's under 1%. Neglible compared to other losses such as radiation.

 

[fleabag]

I'm not talking about European vs North American circuits, I'm talking about 120v 60hz vs 240v 60hz. In the U.S, we have split phase where from the transformer on the pole, it has two out of phase wires coming into the house. Then, if you design your house properly, half the hot wires are one phase and the other half are another phase.

In the case of the oven, stove, and dryer, it takes BOTH "phases" of wire. The wires in most households on 15-20a breakers are around 12-14AWG, so it's better to have two 12awg wires than one 12awg. For my stove and oven, they're on 40a breakers, and it just so happens that they're at 240V. Because they're only DOUBLE the amperage of your regular household outlet and they're running twice the voltage, they can safely use the same sized wire as what goes into your outlets you see scattered around your house because there are more wires running into the circuit. If you run a 40a circuit and only put 10a of electricity through it, it's definitely going to have less resistive losses than a 20a circuit with 10a of electricity going through it. Can't think of a scenario like this? I can!

Most Microwaves here are 120v, which means its on either a 15a or 20a circuit. A high powered Microwave may use up all the power in the circuit, technically up to 12a on a 15a circuit. However, most Microwaves you see are around 1200watts and so they only use 10a of Electricity. Alright, so what about using only 10a on a 40a circuit? Well, generally if a Microwave would suffice for the job of cooking, so would a single burner. Using 1 burner on a stove is probably going to also use around 10a of electricity.

So now the question is, are the resistive losses in energy going through your house to power your devices going to exceed the losses in energy transfer from the resistive heating elements to whatever the hell you're cooking?

That is the question this thread was all about. Unfortunately, the answer for most people is "I don't give a shit, all I care about is being as wasteful as possible whilst spending the least amount of money".

 

[grrl]

<snip>

Just STFU already.

 

[PottedMeat]

For my stove and oven, they're on 40a breakers, and it just so happens that they're at 240V. Because they're only DOUBLE the amperage of your regular household outlet and they're running twice the voltage, they can safely use the same sized wire as what goes into your outlets you see scattered around your house because there are more wires running into the circuit.

what?

 

[fleabag]

what?

On your typical household outlet, you have 2 wires (3 if you include safety ground) and the size of the wire is around 12-14awg. Now on the stove, oven, dyer, there are 4 wires (6 if you include safety ground), two hot (each their own phase), two neutral and two safety ground. These wires in the case of my stove are all 12awg. On older installations, these appliances did not have a safety ground, but that's irrelevant anyway because the safety ground is really only used in the event of a short circuit or a bad neutral.

 

[PlasmaBomb]

Don't insult if you don't know jack shit about everything.

Fixed.

 

[grrl]

On your typical household outlet, you have 2 wires (3 if you include safety ground) and the size of the wire is around 12-14awg. Now on the stove, oven, dyer, there are 4 wires (6 if you include safety ground), two hot (each their own phase), two neutral and two safety ground. These wires in the case of my stove are all 12awg. On older installations, these appliances did not have a safety ground, but that's irrelevant anyway because the safety ground is really only used in the event of a short circuit or a bad neutral.

You really don't understand the basics of wiring, do you? 208 single phase does not use neutrals. Nor does three phase, which your appliances aren't anyway. Plus, why are even bothering to talk about the grounds, they won't have any effect on the silly calculations you claim to be trying to make.

 

[Rubycon]

Wow what a trainwreck this thread has become!

 

[fleabag]

You really don't understand the basics of wiring, do you? 208 single phase does not use neutrals. Nor does three phase, which your appliances aren't anyway. Plus, why are even bothering to talk about the grounds, they won't have any effect on the silly calculations you claim to be trying to make.

I was being as accurate as possible so that asshats wouldn't make such statements like "what about the safety grounds, DURRRR".. We're not talking about 208 single phase... I'm talking about 220/240 SPLIT PHASE. Pay attention! Hell for all I know, you think I'm talking about the difference between 208V 50hz and 120V 60hz.. D:

 

[PlasmaBomb]

Graph them together. I bet as you drive both go up together then back down together when you park.

The only correct way to warm up a vehicle is to drive it, but the argument about warming up the truck in winter at lake tahoe was about IDLING a vehicle to warm it up. You can't idle a vehicle to warm it up and expect the tire pressure to go up. You want to warm up your tires and the car, you drive it because doing it any other way is stupid.

You do realise your comment has nothing to do with IronWing's suggestion...

 

[fleabag]

You do realise your comment has nothing to do with IronWing's suggestion...

You do realize we're not talking about warming up the truck at Lake Tahoe, do you?

 

[PlasmaBomb]

It refers to the fact that users on this board go into a heated discussion about NOT inflating their tires until the sidewall was at the proper height. They said that they could tell when the tires were "inflated to sidewall" when they observed the tires from the outside but it turns out they are wrong and that the only way to know the tire's pressure is when you use a pressure gauge.

Bollocks. That is a blatant distortion of the truth falebag.