Thermal Accumulator by phattpiggie

[General Disaster]

Specific heat is an extensive property. It extends with the quantity of matter.

I've no formal scientific education so I may be wrong but I think you're describing 'heat capacity' which is quantity related, rather than 'specific heat' which is unit-mass based instead.

ZrO2 being denser than boro, there is more mass in a Zirconia filled head than a boro one.

Which is why I was asking if density had a direct relationship with specific heat or whether it had a separate effect of it's own, not asking what density means.
So I assume that density has little direct relationship to specific heat, as you've only used it to calculate the mass, and used specific heat to calculate the energy?

Also keep in mind that specific heat value depends on the measurement protocol and results vary depending on the technic used.

Um, are you really sure about that?
The unit of specific heat is Joules per gram per degree Celsius. All of those three values are absolutes. The weight doesn't change (unless you leave the surface of the planet), the energy change is a set amount, the temperature is the temperature - how can these vary? What different protocols would give different values?

The point of specific heat is it's not conditional to anything but those three absolute values, there's only one specific heat for a particular substance I believe, you don't see a number of different specific heat values for one thing, that I've ever noticed. Granted certain parameters have to be fixed or within a range, such as temperature and pressure, but this is the same as for most standard attributes, like B.pt and M.pt, and many (most?) other physical attributes, it's just part of the definition of these properties of a substance.
"... technic used." - not heard that word before, did you mean technology? Or something else?

Let's do the math.

Must we?

What does that means ?

Pretty much what I described with words instead of numbers? Or were you saying something different?
But the numbers don't do a great deal, in the sense that they're simply saying there's a difference and which one has the greater capacity to store heat. The figures themselves are pretty abstract though and wouldn't represent reality in a ball-head.

We can do the math for rubies and SiC if you want.

Why? It would show what we already know in the sense that the higher the specific heat (or heat capacity) then the more energy needed for an equivalent temperature rise. But as I understand that's what specific heat means in essence, and the calculations only show the relative proportions. I'm not really sure what they are showing here that says more than saying in words which compound has higher specific heat?

 

[Radwin Bodnic]

I've no formal scientific education so I may be wrong but I think you're describing 'heat capacity' which is quantity related, rather than 'specific heat' which is unit-mass based instead.

Yeah you are right. Translation issues I guess. My bad.

Um, are you really sure about that?
The unit of specific heat is Joules per gram per degree Celsius. All of those three values are absolutes. The weight doesn't change (unless you leave the surface of the planet), the energy change is a set amount, the temperature is the temperature - how can these vary? What different protocols would give different values?

Look at this data page :

Properties: Alumina - Aluminium Oxide - Al2O3 - A Refractory Ceramic Oxide

Aluminium Oxide (Al2O3) or alumina is one of the most versatile of refractory ceramic oxides and finds use in a wide range of applications.

www.azom.com

It gives a minimal value and a maximal value for specific heat. And the range is rather broad...

The wikipedia explains why it is not a fixed value but a function.

Why? It would show what we already know in the sense that the higher the specific heat (or heat capacity) then the more energy needed for an equivalent temperature rise. But as I understand that's what specific heat means in essence, and the calculations only show the relative proportions. I'm not really sure what they are showing here that says more than saying in words which compound has higher specific heat?

ZrO2 has a lower heat capacity than boro yet the same amount of balls will be able store more heat in zirc than in boro. Why ?
Because of density of material and mass of the thermal matrix.

 

[Electrofever]

Brings me back to heat and mass transfer class 15 years ago and the dozens of different dimensionless numbers

I totally agree Nice to hear about the physics behind all that !
But I am aware that reality must be much more complexe with many interactions, radiance, conduction, add some convection.

 

[Radwin Bodnic]

Or were you saying something different?
But the numbers don't do a great deal, in the sense that they're simply saying there's a difference and which one has the greater capacity to store heat.

Zirconia has a lower capacity to store heat than boro. But being denser, the same thermal matrix will hold more mass. So the same thermal matrix will store more heat with ZrO2 balls instead of boro despite the lower heat capacity of ZrO2.

 

[Pcloudy]

Zirconia is just zirconium dioxide. Two oxygen atoms for one zirconium atom arranged in a cristalline structure. Together they form a ceramic.


Specific heat is an extensive property. It extends with the quantity of matter.
ZrO2 being denser than boro, there is more mass in a Zirconia filled head than a boro one.

Reminder : heat capacity is the quantity of energy (Joules) you need to apply to a material to raise its temperature up 1°K.
In extension it is also the energy released by the material to lower its temp down 1°K.

Also keep in mind that specific heat value depends on the measurement protocol and results vary depending on the technic used.

Let's do the math.

ZrO2 :
• specific heat capacity : 420 J/(k•kg)
• volumetric mass : 5,85 g/cm3

Borosilicate :
• specific heat capacity : 830 J/(k•kg)
• volumetric mass : 2,23 g/cm3

Let's assume a head filled with 100 x 3mm balls. (R = 1,5 mm = 0,15 cm)
Total balls volume = 100 (4/3 x π x 0,15^3) = 1,41 cm3.

Balls mass with boro = 1,41 x 2,23 = 3,14 g = 0,00314 kg
Balls mass with ZrO2 = 1,41 x 5,85 = 8,25 g = 0,00825 kg

Now imagine room temp is 20°C and the TA head is cold. You the balls at around 220°C to vape your bowl. You need 200°K more. To reach this temp :
• ZrO2 balls need 420 x 0,00825 x 200 = 693 J
• boro balls need 830 x 0,00314 x 200 = 521 J

What does that means ?
To get to the same temp, ZrO2 balls will need more torching (longer or bigger flame) than boro.
But because it has stored more energy ZrO2 will take longer to cool down, releasing more energy than boro.

We can do the math for rubies and SiC if you want.

Hell yeah I want the math for rubies and sic! Math rules. No sarcasm here, I very much would like to at least see the final outcome of the sic and rubies compared to the other two.

 

[General Disaster]

It gives a minimal value and a maximal value for specific heat. And the range is rather broad...

The wikipedia explains why it is not a fixed value but a function.

Interesting, I usually see only one value in general on the occasion I may look something up. What are the different criteria for the minima and maxima? I've seen different values for different temperature ranges, where I presume the properties of the material changes over the range to a significant degree. Is this what you mean? I wouldn't think so from that data sheet you linked to, but it's unclear what the range of values results from, different types of measurement? Some other condition changing? Or is it different molecular structures?

So if I understand correctly, the density is indeed a separate factor in how much energy the material can hold for a particular temperature?
So in this case, the zirc oxide takes more energy because it's much higher density outweighs it's lower specific heat?
And if zirc oxide and boro had the same densitty then it would be the boro than would hold more energy per degree? (assuming same volume of material)

Zirconia has a lower capacity to store heat than boro. But being denser, the same thermal matrix will hold more mass. So the same thermal matrix will store more heat with ZrO2 balls instead of boro despite the lower heat capacity of ZrO2.

Huh! I should have read further!
Thanks! That's good to know, I was missing that piece of the picture!