Thermal Radiation Discussion

[natural farmer]

Modnote: The following 27 posts were pilfered from the Vapman thread.

@OF will not be surprised that I respectfully disagree with this. My money's on some radiation. We need a bookie!

I will insist on radiation as well.

Just like the MFLB or the Crafty or the Solo, the Vapman as well relies quite a lot on radiation. As one manufacturer pointed out recently but I don't remember who right now, herbs are a bad conductor of heat. The part of the load that usually is in contact with the hot oven walls is quite a small amount of the overall load, depending on the load and the oven shape of course. So heat probably doesn't get via conduction in the inner regions of the load but through radiation. I am not sure I understand why you say that about how radiation works. Look at all those radiation heating panels in the market. They just radiate heat to the environment. It's just like ovens work in our kitchens. Before the convection ones (and air circulation can still be stopped anytime in new ovens as well), ovens cooked our food through radiative heat. The food is not in contact with the oven walls. Is it? So is there any other way the heat might get to the food? This is how most of the conduction units work these days. Conduction yes, but a lot of radiation too. I am not an expert but this is what my personal logic says. I'd love some arguments...

 

[OF]

I will insist on radiation as well.

Look at all those radiation heating panels in the market. They just radiate heat to the environment. It's just like ovens work in our kitchens. Before the convection ones (and air circulation can still be stopped anytime in new ovens as well), ovens cooked our food through radiative heat.

OK, I get it it's a popular belief, but here's where I think it's flawed.

First off, consider those heating panels, how hot are they? Much hotter than the store, right? Likewise the oven, you need a couple hundred degrees difference to cook the food in normal times. Much more to broil (which is basically pure radiation, without the normal convection (hot air contacting the dinner)). Convection ovens capitalize on this (conduction/convection heating by hot air) to do the same work in less time at lower temperatures. In a vacuum (no hot air) that home oven would take much longer to cook the holiday turkey.

Now to the non intuitive arguments. Everything that's at all warm is radiating IR. It's basically trying to heat up the world that way. At the same time, the world is trying to heat it. You are comfortable in your clothes because while you're radiating heat out, your warm clothes return the favor in addition to trapping a layer of warm air. Likewise, the kitchen table eventually reaches 'room temperature'. Even in a vacuum (although there it takes much longer due to lack of air).

Second idea: Heat is different from temperature. One is calories (or Joules or BTUs) the other degrees (F or C, depending). Because of English, folks confuse 'heat' (energy transfer) with 'heat' (temperature). Heat (in the terms we want here) is the ability to change the temperature in the load. Transfer energy. Temperature is just a measure of the molecular level vibrations, usually eventually leading to melting as the solid structure breaks down and boiling after that as more and more energy is added. To form an analogy that might help, heat (energy transfer) is a flow, temperature a pressure? They are related by other factors, but are different things.

Still with me? Cool. Now for number 3. To make vapor takes energy. Usually a lot. For instance, with water it takes one calorie to raise a gram one degree C (the definition of calorie), about 4.2 Joules for those using the really fun units (the ones named after dead guys......). Say 300 J to raise that gram of water from room temperature to boiling? To evaporate a gram of it off (without changing the temperature of the gas vrs the liquid) takes over 2000 J. This is why "steam burns" are so bad. The steam isn't all that hot (temperature) but has a huge amount of heat (calories, or Joules) to give up as it condenses on your skin. It's also why swamp coolers work so well (evaporating off the water takes LOTS of heat out of the air doing so).

Now to try to pull together....... To make vapor we too need lots of energy. And to keep making vapor for the hit means we need a constant flow of energy that's quite large relative to heating either the load or vapor a few degrees. In VM that comes from the torch heating the copper. When we're making that vapor the copper is basically the same temperature as the bud and vapor (no burning) so the IR heat transfer from copper to load is nearly the same as the load to copper. Not a lot of calories moving into the load that way. Thermodynamics won't allow it (high rates of transfer). It's the need for constant net energy flow into the load and no 'delta T' (difference in temperature to drive it) that disqualifies IR as the prime process here. Yes, it helps MFLB get to temperature faster (when the screen is hot and the load cold) but it doesn't make more vapor, that has to depend on conduction like in VM. Notice how the load in VM is shallow? Lots of contact with the copper? I don't think that's an accident.

Finally it's a misnomer to call herb an insulator in vapes. Thermocouple measurements with Ascent show this is exactly what's happening through loads much deeper than VM. Remember, locally (within the load) you have hot air (and vapor itself) in the game too. There, like I believe as it is in VM, the bulk of the work (transferring the energy to make vapor) is by conduction.

That's my understanding anyway. It's not as simple as that no doubt, but I think the basics are there in useful/understandable terms? Radiation heating depends on hot sources. The formulas involved reflect this factor. The hotter (relatively), the faster the rate. The sun heats us at 93,000,000 miles (give or take) because it's mighty hot. The moon is much closer, but being not much hotter doesn't contribute to Global Warming near as much even though it subtends a larger angle ('is bigger in the sky') and is closer. Moonlight is significant, but 'moon heating' isn't. It's just not that much hotter there, even at 'high noon'. Since the walls of the oven are basically the same temperature as the load their rate of contribution of heat by IR has to be small once at the magic temperature. And we need big.

Or not.

Regards to all who waded through that. I hope it made some sense. IMO it fits in with the way the rest of the world seems to work.......as it should.

Thanks.

OF

 

[vapman]

Forget radiation. Radiation only works when the hot side is much hotter than the load. My money's on conduction. OF

Allow me to involve myself in the debate about conduction, convection and radiation.

I agree with OF, to heat something by radiation, the heating element must be hotter to much hotter than the medium to be heated up. This applies definitely not with vapman as the herb chamber gets only a little hotter than the herbs.
To me, vapman is a convection vaporizer with some conduction effect when drawing on the mouthpiece.

vapman

 

[OF]

To me, vapman is a convection vaporizer with some conduction effect when drawing on the mouthpiece.

Is that what you meant to say? "Vapman is a conduction vape with some convection effects when drawing" makes more sense to me. Until you puff on it, not much moving......

In any event, I think we're in agreement the radiation contribution is not the driving force here?

OF

 

[Andreaerdna]

"Don't shoot a sparrow with a cannon".

OF

Sorry for the OT

Why do think to the best or worst way to shoot a sparrow?

Otherwise I agree, "do not light the oven with a flame thrower"

About heat transfert by IR radiation in VM I would not exclude it (as in Lotus too and a little with hammer or vaponic).
I mean, while heating with a 1200* C flame for 3-4 secs a gold plated thin copper cone there is a big difference in temperature between copper and leaves.
Rapidly after cutting lighter off they reach thermal equilibrium, that is clear, but while heating with lighter the copper bowl is highly hotter than the contents of it (otherwise it couldn't work ). They are very close (heat source and heat sink) so I think IR radiation is quite involved in vaporizing (heat transfert) with VM, at least while torching the bowl maybe less than conduction but more than convection overall, IMO.

Anyway it would be nice to see a thermal camera on VM bowl from torching to hitting phase

 

[OF]

I mean, while heating with a 1200* C flame for 3-4 secs a gold plated thin copper cone there is a big difference in temperature between copper and leaves.
Rapidly after cutting lighter off they reach thermal equilibrium, that is clear, but while heating with lighter the copper bowl is highly hotter than the contents of it (otherwise it couldn't work )

Actually I don't think that's true. You bring the copper temperature up to about 400F, not 1200F, let alone 1200C (Copper melts just before 1100C...).

If the copper was significantly hotter than 400F the bud contacting it would scorch and combust as it passed 450 or so, right?

Move over, Vapman himself said as much about 12 hours ago:

"I agree with OF, to heat something by radiation, the heating element must be hotter to much hotter than the medium to be heated up. This applies definitely not with vapman as the herb chamber gets only a little hotter than the herbs."

I agree with him (obviously) and estimate that "little hotter" is probably something like 25 degrees? Nothing "big" or "highly hotter" going on.....or we'd be blazing not vaping?

OF

 

[Andreaerdna]

I agree 1200 is way too much, if we talk about the whole bowl. it has his inertia and the flame is applied on only a small portion of the bowl so there is a temperature gradient going from 1200 of the flame to somewhere around 400 on the higher part of the bowl I guess. And I do think a beginning of gold melting happens where flame is applied as on lotus plate.

That being said I admitt I like to discuss about phisics of beautiful objects

 

[OF]

To me the Vapman works by magic alone.

I believe you've summed the condition up exactly.

To bad you didn't post sooner, you could have saved me a lot of typing.......

I agree 1200 is way too much, if we talk about the whole bowl. it has his inertia and the flame is applied on only a small portion of the bowl so there is a temperature gradient going from 1200 of the flame to somewhere around 400 on the higher part of the bowl I guess. And I do think a beginning of gold melting happens where flame is applied as on lotus plate.

Don't confuse heat (calories, Joules or BTUs delivered) with temperature (degrees). Not all degrees are the same. You can wave your hand through that 1200 degrees since the actual energy (in calories say) in the small volume of gas that touches your skin is too small to burn your skin in the time available. Not enough calories to worry about.

OTOH, heat transfer through the Copper is very easy and fast. The entire Copper mass (little more than a concave disc really) is the same temperature within a degree or two, the "temperature gradient" is between the flame and the copper. This is the reason it's Copper (great conductor of heat, as cited by the maker a while back......man knows his materials......). Same as a kitchen pan cooks evenly across the bottom even though only part of it's in contact with the fire or heater element. Thermodynamics explains the details, but that quickly devolves into strange math with even stranger symbols. Usually Greek symbols come to think on it, and you know what king of a mess they've got their numbers in these days.....

Lotus is a whole other thing, I think. There the Nickle plate is very thin and definitely gets much hotter. It in turn heats air (much hotter than 400F) to carry the heat into the load. Here the 'thin' heat of the 'way too hot' air is quickly given up to the mass of the load, much like waving your hand through as you wave it through the flame above, not enough heat available to heat the bulk fast enough to get into trouble before the heat (energy) is conducted away from the surface. Temperature builds slowly. Over time the heat builds up to the magic number in the load, just like it does in the Copper in VM before moving into the load (mostly by conduction again).

All in all I think the magic explanation is more useful......and easier to understand. As long as it works the same way each time, most could (rightly IMO) care less how or why?

OF

 

[vapman]

Is that what you meant to say? "Vapman is a conduction vape with some convection effects when drawing" makes more sense to me. Until you puff on it, not much moving......OF

Thank you OF and sorry for the mix-up!
Of course, I wanted to say that vapman is a conduction vaporizer with some convection effects caused by the three tubes, when drawing on the mouthpiece.

Just to stay on this topic for a bit longer, there are a lot of discussions about which one of the two principles is better. I don`t think that convection is better than conduction or vice versa, it all depends
on the size, material and shape of the heating chamber. In case the heating chamber is small and the distance through the content, enhanced by a certain shape, is short, then conduction can be as good as convection. Vapman actually proofs this, where on the other side, a large chamber needs convection in order to distribute the heat evenly and in time. As mentioned before, the material of the chamber is also crucial, vapman would not work, at least never as well with a heating chamber made of steel, for instance. Vapman has a bit of both worlds and a dash of magic, as MOJO found out.


vapman

 

[Andreaerdna]

Radiation or conduction (time is passed from school, I had to check definitions)

From wiki

Heat conduction (or thermal conduction) is the transfer of internal energy by microscopic diffusion and collisions of particles or quasi-particles within a body due to a temperature gradient ("within a body")

But also

Thermal radiation is electromagnetic radiation generated by the thermal motion of charged particles in matter. All matter with a temperature greater than absolute zero emits thermal radiation.

So heat conduction allows copper bowl to get evenly hot, and heat radiation allows leaves to be evenly heaten in short time (btw leaves are very good thermal insulator not conductor, used as natural material in domestic heat insulation) and holes allows to better suck vapour with a very little covection (air stream cold down very rapidly the 3little golden pipes IMO)

 

[OF]

But also

Thermal radiation is electromagnetic radiation generated by the thermal motion of charged particles in matter. All matter with a temperature greater than absolute zero emits thermal radiation.

Yes, but since both the load and the wall are emitting IR while the wall is heating the load, the load is also heating the wall. The net transfer to the load (making it hotter in degrees) can only happen when it's emitting less than it's getting back.....that only happens when the wall is hotter. In practice a lot hotter (like hundreds of degrees). Since that (large temperature difference) isn't happening, heating by IR isn't either.

In the water analogy heat transfer is gallons per minute (flow rate). Temperature is pounds per square inch (pressure). For a given temperature difference (pressure difference) the flow rate is determined by the missing factor that links them. But when the difference goes to zero, the 'coupling factor' doesn't matter it's still a zero so no more transfer (flow) can happen. Them's the rules.

OF

 

[Andreaerdna]

Yes, but since both the load and the wall are emitting IR while the wall is heating the load, the load is also heating the wall. The net transfer to the load (making it hotter in degrees) can only happen when it's emitting less than it's getting back.....that only happens when the wall is hotter. In practice a lot hotter (like hundreds of degrees). Since that (large temperature difference) isn't happening, heating by IR isn't either.

In the water analogy heat transfer is gallons per minute (flow rate). Temperature is pounds per square inch (pressure). For a given temperature difference (pressure difference) the flow rate is determined by the missing factor that links them. But when the difference goes to zero, the 'coupling factor' doesn't matter it's still a zero so no more transfer (flow) can happen. Them's the rules.

OF

Sorry to insist, I know you are kind OF scientific authority around here, but heat flows from hotter to colder only one way and 1 degree is enough to transfer heat, bowl is always hotter in order to heat leaves and produce vapor, if load is hotter than bowl it means it is cooling down and not producing vapor

 

[hoyo77]

Sorry to insist, I know you are kind OF scientific authority around here, but heat flows from hotter to colder only one way and 1 degree is enough to transfer heat, bowl is always hotter in order to heat leaves and produce vapor, if load is hotter than bowl it means it is cooling down and not producing vapor

http://www.leafscience.com/wp-content/uploads/2014/06/choose-right-vaporizer-4.jpg

 

[Andreaerdna]

http://www.leafscience.com/wp-content/uploads/2014/06/choose-right-vaporizer-4.jpg

sorry, I m not good at painting

really sorry, I think there is a bad use of heat conduction and heat radiation terms. For example if "conduction" vapes works better with fine grind that indicate than conduction isn't the main heat transfer. Conduction work well with solids like metals and very bad with stuff like fragmented row vegetal.

If you want to call a sheep a cow you are free to, but it remains a sheep

edit: I have to admit that conduction vape sounds way way better than radiation vape

 

[natural farmer]

Sorry to insist, I know you are kind OF scientific authority around here, but heat flows from hotter to colder only one way and 1 degree is enough to transfer heat, bowl is always hotter in order to heat leaves and produce vapor, if load is hotter than bowl it means it is cooling down and not producing vapor

 

[Andreaerdna]

Conduction and radiation are married. Where there is thermal conduction there is also thermal radiation. To me these 'heat' arguments tend to become very circular because all these words simply describe what the heat is doing or how heat is moving. It ends up being a battle of semantics based on paper thin points that blur anyway.

absolutely correct but you forget the secret lover: where cunduction marry radiation they both sleep with convection. it is always a question of proportion

 

[OF]

For example if "conduction" vapes works better with fine grind that indicate than conduction isn't the main heat transfer. Conduction work well with solids like metals and very bad with stuff like fragmented row vegetal.

But actually that's exactly what it shows!

Fine grind means there are more contact points, therefore better heat transfer. Sand contacts the walls of the box in far more area than the same box full of rocks.

OTOH, IR doesn't care. Here's a thought if it's all by IR why does grinding help in VM?

nope — herb does not conduct or radiate heat unless it is on fire.

Of course it does, see above the other guy cited 'everything above absolute zero radiates IR'. You radiate IR, how do you think those 'stick it in your ear' thermometers work? In an IR world everything and everyone you know glows, including your stash. Just some things glow brighter than others.

And if it doesn't conduct heat, how do conduction vapes vape the part of the load that doesn't touch a wall (like in Ascent)?

OF

 

[Andreaerdna]

But actually that's exactly what it shows!

Fine grind means there are more contact points, therefore better heat transfer. Sand contacts the walls of the box in far more area than the same box full of rocks.

OTOH, IR doesn't care. Here's a thought if it's all by IR why does grinding help in VM?



Of course it does, see above the other guy cited 'everything above absolute zero radiates IR'. You radiate IR, how do you think those 'stick it in your ear' thermometers work? In an IR world everything and everyone you know glows, including your stash. Just some things glow brighter than others.

And if it doesn't conduct heat, how do conduction vapes vape the part of the load that doesn't touch a wall (like in Ascent)?

OF

I was suggesting by radiation

 

[OF]

In this case it does not apply because the herb never reaches temperatures to conduct/radiate heat to the copper from where the heat comes in the first place.

Don't confuse net flow with not happening. The load is definitely radiating IR or your 'non contact' thermometer wouldn't be able to tell you how hot it is?

Yes, as it heats up less IR leaves than is absorbed (the definition of heating actually), but it's going both ways, right? If not how do you explain the load cooling after the hit?

Again, note the quote above, IR happens at all temperatures you know.

And while on the topic of noting, please also notice the maker of the VM (who seems to know a lot about it) agrees Radiation is not happening (because there is very little difference in temperature) and that VM is primarily a conduction deal with a modest boost from convection during the hit.

I was suggesting by radiation

But you said conduction? That fooled me. But the point you brought up I think actually does prove it's not IR as you suggest in that grinding increases the contact (favoring conduction) but doesn't change absorbtion....and yet grinding helps in VM.

I get it that there's a lot of non intuitive stuff in Thermodynamics, but trust me it all comes together if you accept the classical definitions. Or don't trust me (or VM himself) and go look it up? I'm not making this up, just repeating what I was taught long ago and found to work as predicted in my career. When you get into temperature in vacuum work you quickly find out how IR works since convection is eliminated and you can strictly control conduction. Get more than about 100C above the temperature of the microscope you have your hot stage in and your energy input becomes higher and higher and higher to take successive steps up since 'IR losses' (radiation minus absorption) dominate as much more IR leaves than arrives.

Think about your stove heater element. It only feels hot (by IR, holding your hand near) when it's much hotter than you are. As it cools you have to get closer and closer to sense warmth. Eventually having to touch it. Same in VM. except the wall is never more than a little warmer. To get there it has to touch. IR would not care.

None of this shit matters, none of it, but it's hella fun bantering.

Vas? If this is not a serious discussion, please let me know? If you're just jerking my chain I've better things to amuse myself with...... TIA

OF

 

[Stu]

Thermal radiation is how your oven at home works. Simple as that IMHO. The Vapman is a little oven and transfers heat energy to the load just like your oven transfers heat energy into whatever you're cooking.

 

[Andreaerdna]

Don't confuse net flow with not happening. The load is definitely radiating IR or your 'non contact' thermometer wouldn't be able to tell you how hot it is?

Yes, as it heats up less IR leaves than is absorbed (the definition of heating actually), but it's going both ways, right? If not how do you explain the load cooling after the hit?

Again, note the quote above, IR happens at all temperatures you know.

And while on the topic of noting, please also notice the maker of the VM (who seems to know a lot about it) agrees Radiation is not happening (because there is very little difference in temperature) and that VM is primarily a conduction deal with a modest boost from convection during the hit.



But you said conduction? That fooled me. But the point you brought up I think actually does prove it's not IR as you suggest in that grinding increases the contact (favoring conduction) but doesn't change absorbtion....and yet grinding helps in VM.

I get it that there's a lot of non intuitive stuff in Thermodynamics, but trust me it all comes together if you accept the classical definitions. Or don't trust me (or VM himself) and go look it up? I'm not making this up, just repeating what I was taught long ago and found to work as predicted in my career. When you get into temperature in vacuum work you quickly find out how IR works since convection is eliminated and you can strictly control conduction. Get more than about 100C above the temperature of the microscope you have your hot stage in and your energy input becomes higher and higher and higher to take successive steps up since 'IR losses' (radiation minus absorption) dominate as much more IR leaves than arrives.

Think about your stove heater element. It only feels hot (by IR, holding your hand near) when it's much hotter than you are. As it cools you have to get closer and closer to sense warmth. Eventually having to touch it. Same in VM. except the wall is never more than a little warmer. To get there it has to touch. IR would not care.



Vas? If this is not a serious discussion, please let me know? If you're just jerking my chain I've better things to amuse myself with...... TIA

OF

Load is not at same temp as the copper bowl, at the beginning while preheating there are undreds degrees in difference if I well remember the readings on thermal camera, when load reach good vaporizing temps this diff reduces a lot but you have still enough power to put the fire on , always by thermal radiation. Conduction happens inside each fragments radiation pass through continuity solutions inside the load and acts proportionally to proximity to heat source

 

[vapman]

This discussion seems to devolve into a contest of heat semantics.

I agree with @steama as we all seem to understand what is happening inside the bowl of vapman, we are just debating about terms and their meanings.

With my statement that vapman is not a radiation heater, I did not mean that there is no radiation going on, it is much more because I understand (semantics) something else under radiation heater.
To me a radiation heater is a heater which heats up a medium over a distance of gases (atmosphere) or even a vacuum. The sun is the radiation heater of the earth, for instance.
On a cold day we can sit in the sun and feel the radiation on our skin but as soon clouds are coming in between, the radiation is stopped and we feel cold. Why is this? Because IR radiations are stopped by the clouds and are heating up the cloud instead of me.

Translating this mind game to vapman means, that the hot wall of the heating chamber is radiating (transferring, conducting….) the heat to the gas and solid materials (botanicals) touching the wall, but it is not radiating the heat directly and instantly to the botanicals sitting in the center of the load, because they are behind the "clouds". There is radiation and conduction between the hotter and colder particles inside the bowl, but there is definitely no radiation going directly through it. This is why it takes some time to heat the entire load, the heat gets passed on from particle to particle by conduction, radiation or whatever we want to call it.

No one is wrong here, it is all semantics.

I am not going to explain all this to a cat lying in the sun, she would find out that I`m crazy.


vapman

 

[Andreaerdna]

I agree with @steama as we all seem to understand what is happening inside the bowl of vapman, we are just debating about terms and their meanings.

With my statement that vapman is not a radiation heater, I did not mean that there is no radiation going on, it is much more because I understand (semantics) something else under radiation heater.
To me a radiation heater is a heater which heats up a medium over a distance of gases (atmosphere) or even a vacuum. The sun is the radiation heater of the earth, for instance.
On a cold day we can sit in the sun and feel the radiation on our skin but as soon clouds are coming in between, the radiation is stopped and we feel cold. Why is this? Because IR radiations are stopped by the clouds and are heating up the cloud instead of me.

Translating this mind game to vapman means, that the hot wall of the heating chamber is radiating (transferring, conducting….) the heat to the gas and solid materials (botanicals) touching the wall, but it is not radiating the heat directly and instantly to the botanicals sitting in the center of the load, because they are behind the "clouds". There is radiation and conduction between the hotter and colder particles inside the bowl, but there is definitely no radiation going directly through it. This is why it takes some time to heat the entire load, the heat gets passed on from particle to particle by conduction, radiation or whatever we want to call it.

No one is wrong here, it is all semantics.

I am not going to explain all this to a cat lying in the sun, she would find out that I`m crazy.


vapman

Semantic is important, if someone talk wrong than he think wrong too, it is a bad spiral

My guess related to this misunderstanding is because "conduction" term is quite more popular than "radiation" but there is no conductive vaporizer since dried herbs are very bad heat conductors.

as for example: if you apply a torch lighter on a conductive object (copper bowl) it will become evenly heated because conduction diffuse heat through it. If you compress an herbal matter and apply fire on one end it will start burning while on the oposite side it will remain cold (there is no, or very little, conduction)

In the end i think there is no conductive vape at all (if we talk about the way herbs get heated), what is called conductive vape (vapman,MFLB, or similar) is really a radiative vape.

 

[KeroZen]

I'm glad this discussion took place as I already argued with @OF on that exact same topic in the past. What @Stu said above with the oven analogy is how I tend to understand it.

I set my oven to 220°C and put my cold pizza inside, it doesn't contact the oven walls and there's no active air movement involved, and then it cooks. Even when the pizza is hot it's still cooler than the walls and keeps receiving heat.

If I set my Ascent to the same 220°C temperature (max setting) and put cold bud inside, at first there will be a big temperature differential and it will cook. At some point the bud will be at 220°C and the temp sensor will tend to reduce the heater duty cycle towards zero. The molecules inside the load will be past their vaporization point and any air movement will make them move away from the bud, it will lower the temperature a bit in the process, then the heater will kick in again to compensate...

But there's always a differential no? In the Zion thread the maker said that for instance in a convection vape the nichrome wire has to reach over 1200°F to produce air at 400-500°F. Maybe in the Ascent the bowl walls never exceed say 400°F but the nichrome around the ceramic bowl must be higher temp no? So there's always a gradient / differential...

And OF, you keep saying in the thread that every time you take a hit in the Ascent you can lose as much as 100°F when measuring inside the load. Isn't 100°F a big enough temperature differential?

 

[Tweak]

I'm glad this discussion took place as I already argued with @OF on that exact same topic in the past. What @Stu said above with the oven analogy is how I tend to understand it.

Yeah me too. I never jump into one of these conversations because IMO a vaporizer uses all three form of heat transfer, Radiation, conduction, and convection. So how do we categorize a vape as just one?

According to this infograph:

"Remember!! In practice, almost all vaporizer experiences both convection and conduction to some degree. We can say a device is one or the other based on the dominant effect."

Dominant at what?