Snow, Ice, Heat, and melting times

[WanderingKid]

So I'm having a confusion.  I'm playing around with melting rates on ice and snow in a water tower to use them as passive coolers.  However, the numbers have me confused, they seem backwards to me.

Ice: Spec Heat: 2.05 J/g/K | Thermal Conductivity: 2.18 W/m/K

Snow: Spec Heat: 2.05 J/g/K | Thermal Conductivity: 0.545 W/m/K

To me that means that ice is collecting heat/coolness at 4x the rate of snow... however, it's exactly opposite of what I see. What am I missing?  I'm assuming it's one of those obvious things that I just don't grok yet.

[0xFADE]

Do you have any thermal shift plates or similar around?  Those tend to overwrite values.  Similarly when sending pipes through tiles as well.

I'd have guessed the same thing and would have expected an equal mass of snow and ice in the same situations would heat up at different rates.  Like trying to heat up a room that is full of chlorine.

[QuQuasar]

Snow is insulated by the air within it, so it has a lower thermal conductivity. An equivalent mass of snow will heat up much slower than ice.

 

However, snow in it's natural state has a fraction of the mass of ice, so it will melt a lot quicker. Even if you're collecting it in storage compacters you'll rarely get more than a few hundred kilograms of snow, while you'll get easily be able to mine a full 20t of ice.

[WanderingKid]

@0xFADE  No thermal stuff around.  A giant tank of water and some granite storage containers.

@QuQuasar I was using 2500 kg amounts in multiple storage containers.  I was able to fill them each equally, but the snow ran out long before the ice did.  It was a very thorough removal of the local mini-glacier.

Thanks for the input.  So, the math is what I thought it was, but I'm getting some other kind of affect or modifier.  I can dig around to find that, but I wanted to double check I had the concept straight before I overthought it.

 

[0xFADE]

Are both containers made out of the same thing too?

[WanderingKid]

18 minutes ago, 0xFADE said:

Are both containers made out of the same thing too?

Granite.  Basically making an ice cooler instead of needing to use a radiator or Aquatuner.  I can't promise they all started at the same temperature of granite, however, but it shouldn't be too far off.

[0xFADE]

I guess it wouldn't have really mattered anyway since if the granite overrode something they would likely have melted equally.

[Coolthulhu]

19 minutes ago, WanderingKid said:

@QuQuasarI was using 2500 kg amounts in multiple storage containers.  I was able to fill them each equally, but the snow ran out long before the ice did.  It was a very thorough removal of the local mini-glacier. 

Are you sure you actually had 2500 kg of snow? Most glaciers have so little snow in them that it would melt if the container was in 5C area long before you could fill it up to 200 kg.

And if you actually managed to gather 2500 kg of snow (I'm not sure if it's actually possible) - did you start measuring it at the same temperature as ice? That is, due to low mass, snow "chunks" tend to heat up during transport and storage, while ice tends to stay much closer to temperature it spawned at.

[WanderingKid]

12 minutes ago, Coolthulhu said:

Are you sure you actually had 2500 kg of snow? Most glaciers have so little snow in them that it would melt if the container was in 5C area long before you could fill it up to 200 kg.

And if you actually managed to gather 2500 kg of snow (I'm not sure if it's actually possible) - did you start measuring it at the same temperature as ice? That is, due to low mass, snow "chunks" tend to heat up during transport and storage, while ice tends to stay much closer to temperature it spawned at.

I can confirm the 2500 kg of snow in the container definitely when I started this.  I'd have to go debug mode at this point, that stuff almost ran out the door faster than I could haul it in, so there's no more snow.  Well, anywhere in these two biomes, I'll probably dig out another one or two along the way.

However, no, I wasn't trying to be specific when I started this.  It didn't start as an experiment, it was really "Okay, not a lot of snow, but they'll hold for a while, and I'll set the other 8 to ice."  … then the results seemed flipped to me.  However, mass should be mass.  2500 kg should be 2500 kg of snow or ice, unless I'm not understanding part of the question?

Most of my haulers are couriers, so they're hauling around ~1400 kg/trip.  If the snow is all at the bottom, it's pretty easy to collect up in a single pass.

I understand what you're asking now, I think I may see the problem.  Get back to you in a few.  I've got some digging to do.

[Coolthulhu]

4 minutes ago, WanderingKid said:

However, mass should be mass.  2500 kg should be 2500 kg of snow or ice, unless I'm not understanding part of the question?

I mean, the 2500kg of snow was most likely at much higher temperature than 2500kg of ice before you started looking at both.

Snow chunks tend to have very small mass, so they will heat up significantly by gases from other biomes, even isolating ones like CO2 and chlorine. Ice is in bigger chunks, so it doesn't significantly change temperature on such time scale. There is no temperature exchange between items, only gases/liquids/tiles and items, so it is possible for -5C snow to lie next to -20C ice.

[WanderingKid]

1 minute ago, Coolthulhu said:

I mean, the 2500kg of snow was most likely at much higher temperature than 2500kg of ice before you started looking at both.

Snow chunks tend to have very small mass, so they will heat up significantly by gases from other biomes, even isolating ones like CO2 and chlorine. Ice is in bigger chunks, so it doesn't significantly change temperature on such time scale. There is no temperature exchange between items, only gases/liquids/tiles and items, so it is possible for -5C snow to lie next to -20C ice.

I see what you mean about the chunks heating up.  I may have to go grab a sandbox to see what I thought I saw.  I also just realized part of my mistake is in 'expecting' the same values... I just watched a runner move what I'd originally thought was 9600 g instead of 960 kg.  Um, so yeah, this is most likely me missing the volume of snow I should have expected and going past my initial build and what I *remembered* seeing instead of knowing for sure.

I would SWEAR that I had 2500 kg of snow at one point, but that's probably the other half you're explaining, where the tiny little snow pieces collected up from a huge cold biome dig were probably a lot higher in temperature than the huge chunks of ice that were lying next door.