Thermal Radiation Discussion

[OF]

@Andreaerdna, this might help. I think you might be using definition #2 here. Definition #1 is the correct one when used in the phrase "thermal radiation".

Excellent insight, at least potentially. Somewhere between 'fresh perspective' and 'outside the box'???

Thank you.

OF

 

[Andreaerdna]

For firts @OF sorry "again" of for patronising you, I just sleep collapsed after a little while (too much love to my lotus after a while neglecting him get my very baked), I will pay more attention to what i write

@nopartofme that generic definition about radiate (spread) was already used by @OF when talking about many use of thermal radiation (see yesterday page 2)

What i mean is that if room temp is lower than your one you are a little stove transferring heat through thermal radiation all over you (btw spreading it in a radious way)

Everything above 0 absolute so everithing existing have infrared thermal radiation emission.
Heat transfert happens when a temperature gradient is present (delta T°). If there is continuity (a metal needle heated on its bottom is the classic exemple) heat transfers by conduction (with formulas and constants that describe very well how fast heat is transferred), if there is hot matter passing by (air or water for exemple) it is convection (same as before), if there is no continuity nor hot stream it is solely thermal radiation accounting for heat transfert. As simple as it seems.

In a vapman or MFLB the contact area necessary to account for conduction is very small comparing to the apparent contact area (you have to think microscopic scale) but also compared to IR emission source, that is why I do not agree with the term conduction vapes (btw convection vapes is used in a correct way).
To better understand i repeat a data: if your load was pressed down to the same consistence of metal and shaped to fit in crucible there would be a contact area only 100 to 1000 smaller than you are seeing, that is the reason why conduction is mainly used to describe transfert heat through a solid body and not between bodies.
If two bodies are touching each other (not sexually ;-) there is a very little conduction (you have to take in account real contact area) and depending on geometry of the objects "a lot of" of thermal radiation.
Also two metals in contact share some atomic bond (It is called cold welding), I think it is hydrogen bond, that explain some conduction.

You cannot heat by conduction something that isn't sharing atomic bonds capable to transmit atomic vibration (or oscillation) as a fluffy load gently deposed on a trench or a crucible.

Edit:errata corrige no hydrogen bond in cold welding

 

[KeroZen]

What I still don't get in @OF's definition is why do we get even load cooking in, for instance, the Ascent? The load is always cooked the same at any point, there is no darker surface near the ceramic walls and it's not greener in the middle and the top. There's no need to stir in my "conduction" vapes.

If you take the oldest kind of vaporizer, the hot plate one, I can get the frying pan analogy and to me it's conduction. You get a darker roasting near the plate and the top of the load stays green. Same when you cook a steak, you need to flip it at some point to cook the other side.

Now if you put the same steak in a oven, it will cook way more uniformly. All modern "conduction" vaporizers have some kind of "heat shield" around the bowl that tries to reflect the outwards going heat back into the bowl (well even log vapes have this concept, cf. heat island or the shield in the Bud Toaster)

Maybe the apparent "dispute" is not around whether this radiant heat happens (it's always there) but whether it's powerful enough to have any effect on the vaporization process. A good experiment would be to put some herb in a small spoon and hang it right in the middle above the Ascent bowl (that is without touching the ceramic) and see if the spoon gets hot enough and if you see vapor rising. Obviously you would need to increase the set point temperature because air will act as an insulator but my guess is that it would still cook the load in the spoon. Hot enough and fast enough, that are the questions?

 

[jojo monkey]

@KeroZen thermal equilibrium? just guessing.

 

[Hippie Dickie]

that is the reason why conduction is mainly used to describe transfert heat through a solid body and not between bodies

okay, this is my point of disagreement - from my POV if two bodies are in physical contact it is as if they are the same solid body - at least in my mind. Example: when the PAX is loaded and packed tight, there is no additional thermal radiation - vaporization is from purely, totally conduction 100% from physical contact (i think Newtonian, not Quantum), and this is because the heater is totally covered and there is no surface area of the heater available to provide thermal radiation - the herb absorbs it all. And so the conduction heated herb becomes the thermal radiator, being hotter than the rest of the PAX ... the cooker, not the cooked (with respect to the cooler part of the PAX).

The load is always cooked the same at any point, there is no darker surface near the ceramic walls and it's not greener in the middle and the top. There's no need to stir in my "conduction" vapes.

my guess is that the airflow through the load causes some convective heating. so, good airflow can overcome the negative of conduction heating - a perforated heater surface, perhaps. i've always thought the soldering iron/globe needed better airflow/path.

put some herb in a small spoon and hang it right in the middle above the Ascent bowl

then the spoon becomes the bowl, so thermal radiation from the Ascent bowl will turn the spoon into a conduction heater for the herb. or use a perforated spoon for convection ... better yet, a perforated glass spoon, for purest extraction. i may be biased on this last point.

 

[Andreaerdna]

In such vaporizers where bowl is heating load from all around, it is extracted at first the oil/vapor from material in contact or closer to heating source through some conduction/radiation, making the first layer even more insulator (like ashes are), from there on it is only possible radiation IMO: first browned layer act as even better insulator for transfert by conduction while at the same time it becomes more permeable to thermal radiation (due to mass lost through vaporization)

 

[Hippie Dickie]

like ashes are

i agree on some insulating effect ... however, the ABV is still the same herb - i.e. it has more mass than ash, so not exactly like ash. and every insulator will absorb heat (except vacuum), so some conduction will continue.

it becomes more permeable to thermal radiation (due to mass lost through vaporization)

yeah, i don't see that happening ... rather, the vaporizing trichomes and melting plant wax creates holes throughout the herb for more air flow - so more convection than radiation at that point.

 

[OF]

For firts @OF sorry "again" of for patronising you, I just sleep collapsed after a little while (too much love to my lotus after a while neglecting him get my very baked), I will pay more attention to what i write

Apology accepted again. No need to revisit the past. There will not be a third time. You've had a second chance at being civil, please don't look for a third. TIA.

I'll continue to maintain radiation heat transfer needs photons (not detectable in conduction), is only effective at transferring heat energy in if the difference is very large, and is well characterized by the rules others and I am trying to relate. Otherwise I'm just repeating myself. "Lots of chopping with no chips flying" as we say 'out West'.

We may have gone to school in two different countries, in two different languages, but I feel the rules are the same the world over. Throughout the known universe for that matter. Your theories would not earn good grades in my class, should I still be in that business. The engineering disciplines (like the heat management example above) are well established on traditional Thermodynamics and used extensively, the empirical proof?

Perhaps someone else has better words to offer, mine seem to be failing (not the first time.....).

OF

 

[Andreaerdna]

A big temperature gradient make any heat transfert faster, as in conduction or convection also in radiation; that is maybe the only data in common betwen differents heating way

you seems to ignore that heat transfert through thermal radiation can be driven specifically by the area of heating source and the distance from the heated object.

Would be nice if you explain with your words why (without talking about others variables) is necessary a big difference in températures? Btw what is this big difference? Between sun and earth there is huge delta t° but even bigger distance, in mflb or vm the difference in temp is a lot smaller but distance near 0, it isn't so complicate to understand in real applications, and theory is quite clear.

You really do not need to use all those big words (entropy, enthalpy, quantic theory, now photons...btw I will try to make a photo of one of them next time a roast a chicken in my electric oven :-) to make difference between conduction and radiation.

All being said I think too is useless to go on debating, let say we agree we disagree :-)

Best to you.

 

[GetLeft]

Thanks for the lessons, folks. I'm woefully undereducated in all things related to physics, so this has been a nice discussion to read on a Sunday morning turned afternoon. (You should have heard me yesterday as the Pioneer guy tried to troubleshoot me through my receiver failing to transfer television sound from my receiver to my speakers. The help folks at Pioneer are smart. And patient. It was the port on the cable box.)

So energy can be transferred through a body or between one body and another body (VM to plant material) without radiation occurring. Got it. No release of photons required for a conduction vaporizer. That level of energy is not required.

With enough energy added, however a body (any body) can be made to move beyond conduction (for transferring energy) to releasing photons as a means of transferring energy, correct? The spoon / Ascent analogy offered above would require a significant increase in the energy source to heat the air (via radiation) to the point that the spoon reached a temp capable of vaporizing the plant material (via conduction).

 

[Stu]

So energy can be transferred through a body or between one body and another body (VM to plant material) without radiation occurring. Got it.

Not quite. All matter emits (and absorbs) IR radiation. The question is whether the transfer heat energy is enough to make a difference in the process of vaporization. I think I showed that it clearly is in the video I posted in this thread. People just disagree about it for some reason.

 

[OF]

Would be nice if you explain with your words why (without talking about others variables) is necessary a big difference in températures? Btw what is this big difference? .

You really do not need to use all those big words (entropy, enthalpy, quantic theory, now photons...btw I will try to make a photo of one of them next time a roast a chicken in my electric oven :-) to make difference between conduction and radiation.

OK, one more try? And I'm sorry it is necessary to use big words. Or at least big concepts (by whatever name) linked together to make an understanding. It is a dynamic, not static thing. Thermo Dynamics. It can't be seen as a snapshot, but as a time related ongoing process.

So we want to make vapor. That takes heat (in calories). First to heat the material to an energy to evaporate then supply enough extra energy to actually make it evaporate (change state). This is local temperature of that atom if you will, since there's a distribution (the two "E words", things are random). As the average temperature goes up, so does the percentage (and therefore number) of atoms 'near the line'. It's important to remember the idea of equilibrium, at any point in time some are evaporating and some condensing. The ratio shifts is all. Condensing is also subject to pressure, which is why water boils at lower temperature in Denver where there is less pressure (which favors evaporation). When the average temperature of the liquid matches 'vapor pressure' with the outside world we boil.

However, actually evaporating takes a lot of energy but gives no temperature rise. Using water again a single calorie raises a gram of water from 99 to 100C. However it takes an additonal 546 more
calories to evaporate to steam (boil) and go to 101C. That huge, really. This "latent heat of vaporization" is the reason steam burns are so bad, it's not the heat per se, 100C air is not a big deal relatively. Five times what took to take it from just melted to boiling. This is why a pot of water takes so much longer to boil away than to start boiling. I've no idea of the latent heat of vaporization for THC is, but the same effect is sure to be in play. Evaporation takes a huge toll on heat flow. Evaporating that single gram of water to steam takes more energy than needed to raise half a liter a degree. We need a constant flow to supply the much larger amount of energy needed on an ongoing basis or vapor stops. That means we need a strong heat flow (in terms of calories per second). If that flow fails the rate of vapor production drops and eventually stops. Increasing the flow (within reason) raises the vapor rate but not the temperature since that energy goes into latent heat not temperature rise.

With me so far? Great, we're almost there. How to get that heat in...... Taking the case of IR by the horns; the rate heat (in calories) enters is a matter of how much hotter the source is (in degrees) and what the 'coupling' (distance and so on we're not changing). Right? So bigger differences mean bigger rates. It's an analog bipolar line, like your bank account, it can be negative. Put a hot VM in the freezer and IR, no matter how modest, is now cooling it. Like the tide in a bay, it can flow in or out or stand still at equilibrium. Engineers, in their own quaint way refer to this as 'heat load', basically thermal power. They rate heating and cooling needs for a building in BTUs (ton of water one degree F IIRC) or 'tons' (heat necessary to melt that much ice).

Think of the IR coupling as a zero center speed control on an electric train? Turn the knob up (make on side hotter than the other) and the train goes faster and faster as you increase. Lower it slowly (less difference) and it slows to a stop, keep going and it goes backwards. Slowly at first then again faster and faster. A continuous range.

So it's not as much a matter of temperatures difference (in degrees) as what that means in the rate of transfer of heat (calories per minute). Heat we have a huge appetite for. A dynamic thing, not enough heat to support the work we want to do. Not an effective means of moving calories in faster that they come out.

As too how much difference is needed for the task, that gets deep into formulas that need information we don't have. As a seat of pants guess several hundred C? The only real IR vape I know is Bender, and there the source is over 1300C hotter than the load. Bender does make some impressive vapor, but the emitter is large as is the delta. It's a number so big that Rene also doesn't think it's possible? You get warmed by the sun as you point out, but not by the moon even though it's much hotter than you are and much closer than the sun?

So energy can be transferred through a body or between one body and another body (VM to plant material) without radiation occurring. Got it. No release of photons required for a conduction vaporizer. That level of energy is not required.

With enough energy added, however a body (any body) can be made to move beyond conduction (for transferring energy) to releasing photons as a means of transferring energy, correct? The spoon / Ascent analogy offered above would require a significant increase in the energy source to heat the air (via radiation) to the point that the spoon reached a temp capable of vaporizing the plant material (via conduction).

Sounds right to me with a minor correction. Everything is emitting energy by IR if it's above absolute zero (which means everything really.....). "Cold, empty space" is still shining on us at something like 5 degrees Kelvin (above zero). And everything is also absorbing. If at the same rate, that's equilibrium, no temperature change. So it doesn't magically 'start' to happen, it just the balance shifts slowly as the difference increases (you lose or gain faster than you gain or lose).

Not quite. All matter emits (and absorbs) IR radiation. The question is whether the transfer heat energy is enough to make a difference in the process of vaporization. I think I showed that it clearly is in the video I posted in this thread. People just disagree about it for some reason.

With the boss up to the 'clearly showed' part. One of these fine days I want to get back to messing with this but for now I'm quite confident VM is not using IR.

Thanks Stu. Hey I'm with you on the first 2/4 sentences all the way, not bad for a start? I might even give you the fourth.

And thanks to all our readers......

Merry Christmas to all.

OF

 

[Andreaerdna]

I'll continue to maintain radiation heat transfer needs photons (not detectable in conduction), is only effective at transferring heat energy in if the difference is very large, and is well characterized by the rules others and I am trying to relate. Otherwise I'm just repeating myself. "Lots of chopping with no chips flying" as we say 'out West'.

OF

Would be nice if you explain with your words why (without talking about others variables) is necessary a big difference in températures? Btw what is this big difference? Between sun and earth there is huge delta t° but even bigger distance, in mflb or vm the difference in temp is a lot smaller but distance near 0, it isn't so complicate to understand in real applications, and theory is quite clear.

You really do not need to use all those big words (entropy, enthalpy, quantic theory, now photons...btw I will try to make a photo of one of them next time a roast a chicken in my electric oven :-) to make difference between conduction and radiation.
.

So it's not as much a matter of temperatures difference (in degrees) as what that means in the rate of transfer of heat (calories per minute). Heat we have a huge appetite for. A dynamic thing, not enough heat to support the work we want to do. Not an effective means of moving calories in faster that they come out.

As too how much difference is needed for the task, that gets deep into formulas that need information we don't have. As a seat of pants guess several hundred C? The only real IR vape I know is Bender, and there the source is over 1300C hotter than the load. Bender does make some impressive vapor, but the emitter is large as is the delta. It's a number so big that Rene also doesn't think it's possible? You get warmed by the sun as you point out, but not by the moon even though it's much hotter than you are and much closer than the sun?


OF

Parole parole parole...

You surely like to digress :-) and after justifing the need for big concepts to explain a simple natural phenomenom, the answer to the question I ask you is: "...a dynamic thing, not enough heat to support the work we want to do..."?

don't look at my question from a sarcastic POV but you have to admit that you use a lot of words to say simple things. Kinda like to complicate?

Also "work" in physic has a meaning that makes it out of place when talking of heat transfert FYI, but you surely know

 

[OF]

Also "work" in physic has a meaning that makes it out of place when talking of heat transfert FYI, but you surely know

No, once again I don't know that, I thought you were going to cut that out? I am not lying, trying to deceive, acting out of ignorance, trying to cover up or anything else despite your snarky insistence.

Work is exactly the correct term in Thermodynamics I think......I suspect this too points to the base problem here:

In thermodynamics, work performed by a system is the energy transferred by the system to its surroundings, that is fully accounted for solely by macroscopic forces exerted on the system by factors external to it, that is to say, factors in its surroundings. Thermodynamic work is a version of the concept of work in physics. (emphasis theirs, including links).

https://en.wikipedia.org/wiki/Work_(thermodynamics)

Goodby.

OF

 

[Andreaerdna]

if you read what you qoute (the whole thing I mean) you will learn that there is no work at all in what we do (heating some dry leaf)

in common with heat work have only the ability to transfer energy.

I quote this part for you (read last sentence) same page as you btw (wiki)

start of citation

In thermodynamics, the quantity of work done by a closed system on its surroundings is defined by factors strictly confined to the interface of the surroundings with the system and to the surroundings of the system, for example an extended gravitational field in which the system sits, that is to say, to things external to the system. There are a few especially important kinds of thermodynamic work.

A simple example of one of those important kinds is pressure-volume work. The pressure of concern is that exerted by the surroundings on the surface of the system, and the volume of interest is the negative of the increment of volume gained by the system from the surroundings. It is usually arranged that the pressure exerted by the surroundings on the surface of the system is well defined and equal to the pressure exerted by the system on the surroundings. This arrangement for transfer of energy as work can be varied in a particular way that depends on the strictly mechanical nature of pressure-volume work. The variation consists in letting the coupling between the system and surroundings be through a rigid rod that links pistons of different areas for the system and surroundings. Then for a given amount of work transferred, the exchange of volumes involves different pressures, inversely with the piston areas, for mechanical equilibrium. This cannot be done for the transfer of energy as heat because of its non-mechanical nature.[19]

End

 

[Stu]

From that wiki:

For a closed thermodynamic system, the first law of thermodynamics relates changes in the internal energy to two forms of energy transfer, as heat and as work.

So heat and work are distinctly separate. With me so far?

This distinction between work and heat is essential to thermodynamics.

Work done is the transfer of heat into another form of energy (typically mechanical / kinetic energy although other types of energy transfer as well). Think heat engines that drive a turbine or piston... the kinetic energy created by the system has to be accounted for by the laws of thermodynamics. It's the energy that moves from the "heat" ledger and into the "work" ledger. It's just the transfer of energy from one form (heat) to another (kinetic).

Work is exactly the correct term in Thermodynamics I think......I suspect this too points to the base problem here:

I agree with the second sentence.

 

[OF]

From that wiki:

So heat and work are distinctly separate. With me so far?

Work done is the transfer of heat into another form of energy (typically mechanical / kinetic energy although other types of energy transfer as well). Think heat engines that drive a turbine or piston... the kinetic energy created by the system has to be accounted for by the laws of thermodynamics. It's the energy that moves from the "heat" ledger and into the "work" ledger. It's just the transfer of energy from one form (heat) to another (kinetic).



I agree with the second sentence.

Yep, that's the classic conversion, change in pressure for a fixed gas volume, or change in volume for a fixed pressure. We're not doing that of course.

Since energy can't be created or destroyed, all we can do with Thermodynamics is move it around or change it's nature?

Please do this test: Enter "definition of work in thermodynamics" in Google. The returned definition comes from the first 'hit':

"In thermodynamics, work is the quantity of energy transferred from one system to another without an accompanying transfer of entropy. It is a generalization of the concept of mechanical work in mechanics. In the SI system of measurement, work is measured in joules (symbol: J)."

I therefore believe describing movement of heat (transfer) to fit the definition of work in Thermodynamics if not in Physics (where it's force times distance) or Finance (where it's trading labor for mere money).

Not that this really matters a whit WRT making vapor by radiation, unless you're looking for something to quibble over?

FWIW I'm still hung up on this idea that radiation is necessary to conduction transfer, has anyone got something to explain/back that up? TIA

OF

 

[Andreaerdna]

Yep, that's the classic conversion, change in pressure for a fixed gas volume, or change in volume for a fixed pressure. We're not doing that of course.

Since energy can't be created or destroyed, all we can do with Thermodynamics is move it around or change it's nature?

Please do this test: Enter "definition of work in thermodynamics" in Google. The returned definition comes from the first 'hit':

"In thermodynamics, work is the quantity of energy transferred from one system to another without an accompanying transfer of entropy. It is a generalization of the concept of mechanical work in mechanics. In the SI system of measurement, work is measured in joules (symbol: J)."

I therefore believe describing movement of heat (transfer) to fit the definition of work in Thermodynamics if not in Physics (where it's force times distance) or Finance (where it's trading labor for mere money).

Not that this really matters a whit WRT making vapor by radiation, unless you're looking for something to quibble over?

FWIW I'm still hung up on this idea that radiation is necessary to conduction transfer, has anyone got something to explain/back that up? TIA

OF

Definition is right, your interpretation is wrong.
work is a way to transfer energy, heat too but they simply are different ways.

Example of this:
You can heat VM by lighter or station, both transfer energy by heat but you do not call the station "lighter" and vicevetsa, isn'it?

About you hanging on: what I adfirmed is that if there is conduction between TWO solids in contact it is because one is hotter, therefore transferring energy by thermal radiation too. Hope you can relax and chill.

Nobody knows everything but if we are courious and patient and capable to listen we can learn all we want nowadays!

Best to you

 

[KeroZen]

Ok guys, I'm more an empirical/experimental kind of person. So while I understand your theoretical talk, what matters to me is what I can test and see of the "reality"... So in the name of science I did the experiment I hinted above and in fact, I improved it to remove the conduction from the spoon, as there was no spoon involved at all!

I took some pictures but I'm reluctant to post anything related to the plant online, so you will have to take my word for it! The nice part is that @OF got an Ascent too, so he will be able to perform the exact same experiment and see for himself.

I took a very small bud and trimmed most of it so it was round and I kept a long enough "naked stem". I then used a pair of pliers to hold the bud by the naked stem, hanging downwards with the pliers always well above the bowl (in order to minimize the possible conduction effect from the metal pliers into the bud, I think it was completely eliminated because if conduction there was, it would only transfer heat to the dry stem and not to the bud)

I had to trim the bud a lot to make sure no bit was touching the ceramic bowl walls at any time. Holding the bud was not an easy task as any slight movement could make it touch the walls, but it's do-able if you have steady hands.

The Ascent was powered on and set to 212°C. I left it with the lid opened to heat empty for exactly 5 minutes, in order to reproduce the "heat sink" effect that happens during an extended session where the entire device bottom becomes almost uncomfortably hot to touch. The "heat shield" and reflection effects took place and the bottom was already warm after 5 minutes but not as hot as it can be during a classic 20 minutes session (my sessions with this vape are always 15+ minutes)

So after 5 minutes empty I took the bud and the pliers and hung it right in the middle of the bowl, then started a timer. There was a wisp of vapor starting about 20 seconds in, then a continuous stream past the 30 seconds mark. I held it for 5 minutes in total. At no single moment the vapor stream was disrupted, it was steady. Note that there was minimum airflow (it was indoors at my desk and I wasn't blowing near the heater nor using the stems etc) Hot air rises, so did the vapor, like a plume.

After 5 minutes the bud was golden brown and crumbled into dust when I pressed it. End of the experiment. Draw the conclusions (or delusions) you like.

 

[Andreaerdna]

Ok guys, I'm more an empirical/experimental kind of person. So while I understand your theoretical talk, what matters to me is what I can test and see of the "reality"... So in the name of science I did the experiment I hinted above and in fact, I improved it to remove the conduction from the spoon, as there was no spoon involved at all!

I took some pictures but I'm reluctant to post anything related to the plant online, so you will have to take my word for it! The nice part is that @OF got an Ascent too, so he will be able to perform the exact same experiment and see for himself.

I took a very small bud and trimmed most of it so it was round and I kept a long enough "naked stem". I then used a pair of pliers to hold the bud by the naked stem, hanging downwards with the pliers always well above the bowl (in order to minimize the possible conduction effect from the metal pliers into the bud, I think it was completely eliminated because if conduction there was, it would only transfer heat to the dry stem and not to the bud)

I had to trim the bud a lot to make sure no bit was touching the ceramic bowl walls at any time. Holding the bud was not an easy task as any slight movement could make it touch the walls, but it's do-able if you have steady hands.

The Ascent was powered on and set to 212°C. I left it with the lid opened to heat empty for exactly 5 minutes, in order to reproduce the "heat sink" effect that happens during an extended session where the entire device bottom becomes almost uncomfortably hot to touch. The "heat shield" and reflection effects took place and the bottom was already warm after 5 minutes but not as hot as it can be during a classic 20 minutes session (my sessions with this vape are always 15+ minutes)

So after 5 minutes empty I took the bud and the pliers and hung it right in the middle of the bowl, then started a timer. There was a wisp of vapor starting about 20 seconds in, then a continuous stream past the 30 seconds mark. I held it for 5 minutes in total. At no single moment the vapor stream was disrupted, it was steady. Note that there was minimum airflow (it was indoors at my desk and I wasn't blowing near the heater nor using the stems etc) Hot air rises, so did the vapor, like a plume.

After 5 minutes the bud was golden brown and crumbled into dust when I pressed it. End of the experiment. Draw the conclusions (or delusions) you like.

Good job, you do chop the bull's head off! Nice :-)

To go further it is to know that radiation decrease with distance from heater. So if you load normally there is more heat transferred to the load always by thermal radiation, and a very little by conduction

 

[OF]

After 5 minutes the bud was golden brown and crumbled into dust when I pressed it. End of the experiment. Draw the conclusions (or delusions) you like.

Interesting experiment, I'll put it on the list of things to try sometime. My initial take is it's convection going on. Radiation heating is nearly instant. Ever try a Bender? Even though the load mass is big, it's very responsive, much more than I think you're claiming? What do you suppose would happen if you introduced a modest airflow in the bowl? It won't change radiation but will kill conduction/convection I think. And for sure all the power available would not take five minutes to fully cook such a small amount if it was still all coming by radiation?

BTW, radiation depends only on the surface of the emitter. Parts of the body 'it can't see' can't effect it.

Fun idea, but I don't see it as proof there's a lot of radiation going on....and IIRC the maker of this vape too has confirmed he thinks it's conduction, not radiation? By way of experiment, please remember that the reason the glass flowers have so much effect is because of conduction, there is no change in any radiation there?

Good job, you do chop the bull's head off! Nice :-)

And I would be the decapitated bull? Very ISIS like........and not very nice to be cast as the bull.

OF

 

[Snappo]

When the hot summer sun beats down on my roof, it can get hot as hell inside. Same with my car. Conduction? Radiation? Combo of both? Gamma Ray? Cosmic Ray? Convection? None of the above? All of the above?

I debated this on FC long ago, and still maintain that there is radiation at work in both the Solo and the Ascent, among others.

 

[Andreaerdna]

The bull is the debate...cmon you are joking I hope.

And if I may, it is more french revolution like :-)

It is a way to say the debate is dead and this because a proof supporting official theory has been produced, useless to debate further even if you or even god disagree, this is science not religion or art

When the hot summer sun beats down on my roof, it can get hot as hell inside. Same with my car. Conduction? Radiation? Combo of both? Gamma Ray? Cosmic Ray? Convection? None of the above? All of the above?

Sun heats metal on the top of your car by radiation, conduction diffuse heat through metallic case of your car and radiation from the case transfer heat inside/outside your car. Thermal radiation passes through glasses too heating the inside surface of your car (if you have black finitions that is the worst) that start transferring heat through thermal radiation again (and little natural covection too)

 

[KeroZen]

Well I sure don't want to cut anyone's head, be it fellow members or animals!

I don't know what is happening, but I know we've been collectively wondering for a while why the Ascent has such a great taste for a conduction vaporizer. I closely read all other conduction vape threads and even own my fair share (FM5s, FM5Pro, FM8, HD, HE, XMax, FM-VT1, even tried a Pax) but it seems none of them can match the Ascent taste, and that is something that has always intrigued me.

We know it's not the ceramic (other have the same kind of bowl, but I find that ceramic is better than stainless steel taste-wise, IMHO), it's not the glass air path (but it could contribute) so it's down to the length of the vapor path (travels through the entire device height) that allows adequate cooling (I find that the cooler the tastier, for some reason) and also, I think, to the gentle heating and the effect I tried to demonstrate, whatever we chose to call it.

All other conduction vapes are more akin to the frying pan analogy (or the old hot plates vape if you will) and most agree that they give a "roasted taste" as the session progresses. With the Ascent it's more subtle. One might argue that it's because it's under-powered, so it cooks the load very gently by conduction. But at the same time it's quite a large bowl compared to say pen-style vapes, and yet the load is very uniformly cooked without stiring. This is what led me to wonder if something else wasn't happening.

Note that I think the device bottom needs to get very hot (the "heat sink" I described) for the effect to happen, otherwise it's mostly conduction. But when you use the device, the first few minutes are not as productive as latter down the session. You need to get it going for it to produce good vapor (well, good is subjective as it's relatively light compared to convection vapes for instance)

But it feels like when it's hot, and due to the bottom section design, part of the heat that is radiating outwards bounces back inside the bowl from all around, and this have some effect on the process. It would surely take more time and be less efficient if it was the primary source, so I do agree that this is primarily a conduction vaporizer (I don't care if at the atomic level the surfaces are really making contact or if there are minute gaps, to me it's conduction) but this extra effect does seem to have a noticeable impact on the vaporization process.

Now is this conduction heating the air inside the bowl which in turn heats the bud via convection or is it really radiation, I don't know. But it feels more like the turkey oven analogy than the frying pan.