Hence, I'm only imagining it as "conduction+convection=more heat, herb doesn't cool down in the middle of hit and more efficient use of battery."
But conduction and convection don't really happen together like that I think. The hottest part of the system is the metal cup. Any conected air, heated by that cup, can't be any hotter. Nor can the stem wall or any part of the load. The best it can be is as hot as the cup. 'Real' convection vapes (like say Volcano or T1/Cera) have sources very much hotter (like 1000F hotter......) since that hotter air is what brings the neat necessary to make vapor as it cools to 400F. If it enters at 400F and leaves at 400F it doesn't do any work?
As long as that heat source doesn't collapse in the hit too much (it can drop several hundred degrees easily, you can see the glow dim and change color) it can make as much vapor as you can suck up. If that stored energy (in the mass of the hot part) is big enough 'time constant wise' for the heater control to kick back on you're only limited by the herb load (like a Volcano blowing bags). And such systems 'start and stop on a dime' once the load is warmed up. Very fast response.
Conduction is more about time. And having a fresh stem can mask it to make it even more fun. But, as the load progresses, pausing between hits 'for it to recover' gives a bigger hit? That is the 'heat soak' of conduction as it recharges what was used making vapor for the last hit. Again, convection doesn't do this since the heat energy is constantly on tap.
Efficient power use should be looked at as a system I think. You draw power to make vapor. We need
a kWh per gram of THC evaporated rating? More power needed, the less efficient?
So, at a system level, two useful keys are good insulation to lower heat lost to the outside world and not heating any more air than you absolutely have to to make vapor since that too is a straight out power loss (and ironically rougher on the user?). There's a whole class of fairly similar conduction vapes like Air/Solo, the FMs, Pinnacle, my new Linx Gaia and so on. Cylindrical loads about 3/8 in diameter and half an inch tall. All have 'fair to good' insulation and when sipped get about 4 or 5 loads per charged 18650.
Cera will get less than half that performance. T1, with worse insulation (more loss) gets maybe half of that? A second load on a fresh battery is not guaranteed.
In the end vapor is vapor. Cooked is cooked. But same as cooking technique can change energy used to make a meal, so can vape design. Same basic rules.
Fun stuff, but in the end it's enjoying the process and result. The old journey and destination thing? Results count, theory not so much. It's a personal thing in the end, as most things are.
OF
