• BCsven@lemmy.caEnglish
    892·
    26 days ago

    Till it all gets to temp then it won’t do much. It needs some more surface area to convect heat better.

    With enough fins you don’t need fans.

    • cRazi_man@europe.pubEnglish
      22·
      26 days ago

      Would a slow small fan still make a huge difference to the cooling here? Completely passive cooling seems like something that would only make sense in very specific professional environments (like needing an ultra low sound floor in an audiology chamber or recording studio).

      • fartographer@lemmy.worldEnglish
        73·
        26 days ago

        I had a roommate who was getting his doctorate in chemical engineering, specifically focused on graphene. He was able to demonstrate how doping the materials in a heat sink to alter their ability to “release” heat, and then organizing these intentional hotspots along the length of the fins, you could create an active airflow using a stationary object.

        But then his lab manager killed his grant and instead put him on a project partnered with BMW to make their bumpers more marketable.

          • Semjeza@fedinsfw.appEnglish
            6·
            25 days ago

            Many folks in higher education in the UK have been bemoaning a generation of genii lost to business and the City who put their talents and creativity to the good of making profit rather than inventing and humanity.

            Many more have their funding and direction tilted to capital, too.

            • Aceticon@lemmy.dbzer0.comEnglish
              4·
              25 days ago

              If you’re a Mathematical prodigy you either become a Quant making mathematical models for Price and Risk of Over The Counter (so, not sold in a Market) derivatives or, if you have good salesmanship skills, a Trader of such financial instruments.

              None of this brings any actual improvement to Mankind but it sure pays well (more the latter than the former) since the way our Economic System is structured and as a side-effect of unbalancing the playing field to make sure the wealthy get ever more wealthy, Money is the thing that makes the most Money, and even just a tiny slice of such flows is far more monetarilly rewarding than almost all other forms of creation or discovery.

      • BCsven@lemmy.caEnglish
        9·
        26 days ago

        The case has an opening for a vertical fan but it is not needed unless you do heavy gaming and run a high end GPU. For video rendering and other tasks the fins are rated to keep it at a decent temp.

        I have good hearing, and a HDD spinning or even a “silent” fan is still audible droning noise to me.

        This build is totally silent. The PSU is over-rated on purpose because it has a below 30% max draw mode that is fanless.
        So this case makes 0 noise.

    • Gork@sopuli.xyzEnglish
      16·
      26 days ago

      With big enough copper block it might not matter (like the size of a house, but of the good quality stuff not that shit Ea-Nasir sells).

  • stoicmaverick@lemmy.worldEnglish
    54·
    26 days ago

    Okay, who gets to be the lucky one to calculate the amount of time that thing could heat sink a pegged, modern, 120w TDP CPU before it throttles at 100C? I’ll give you a sticker.

    • KSP Atlas@sopuli.xyzEnglish
      59·
      26 days ago

      Let’s assume the dimensions of the copper block are 40mm40mm160mm (I’m not taking the heat spreader into account here)

      That results in a volume of 256000mm3, or 256cm3

      Copper (at 20C) has a density of 8.935 g/cm3, so that’s roughly 2.28736kg of copper

      Copper has a specific heat capacity of 384.603 J/(kg K)

      Using E=cm∆t, we can figure out that it would take ≈ 70378J of energy to heat the copper block to 100C, starting at 20C

      With a TDP od 120W, that means it would take 586 seconds to heat the block to 100C, or 9m46s

      This is probably way off but I was bored

      • Contramuffin@lemmy.worldEnglish
        26·
        25 days ago

        Hmm, I think at minimum calculus will need to be involved here. Because we can’t just assume that the heat is spread evenly in the copper - it’ll likely be hotter at the bottom, leading to thermal throttling earlier than expected. On the other hand, there’s going to be heat dissipation into the air, which will help cool the block somewhat

        Edit: made a program to model heat transfer and heat loss. It seems to only affect final time by a handful of seconds. So actual time in real life is probably somewhere in the ballpark of 10 minutes

          • Contramuffin@lemmy.worldEnglish
            7·
            25 days ago

            Copper conductivity is fast, sure, but it’s not fast enough to have equal temperatures at the top and bottom for such a big chunk of copper. That does affect the time to thermal throttle pretty significantly, actually. If we assume completely homogeneous temperatures across the block (ie, instantaneous heat transfer), according to my model, it’ll take 703 seconds to thermal throttle. With heat transfer, the time drops to 592 seconds - a difference of about 2 minutes

          • Contramuffin@lemmy.worldEnglish
            3·
            25 days ago

            I left another comment going into more detail about the model specifications, if you’d like to read into it. But briefly: I took the copper heat conductivity coefficient and the air heat transfer coefficient. I sliced the copper block into thin slices and modeled heat transfer between each slice, as well as heat transfer between each slice and the surrounding air.

            It seems that both heat transfer and heat loss do actually matter quite significantly, but they just cancel each other out almost entirely.

            If we assume instantaneous heat transfer, thermal throttling time goes up from 592 seconds to 703 seconds (about 2 minute difference).

            If we assume no heat loss to the air, thermal throttling time goes down from 592 seconds to 500 seconds (about 1.5 minute difference).

            • Eheran@lemmy.worldEnglish
              1·
              25 days ago

              If they cancel out, the system would be in balance and not get hotter. So some thing does not add up. What heat transfer coefficient did you use and which other numbers etc.?

              • towerfulEnglish
                1·
                25 days ago

                No, the heat propagation through the copper block (meaning the contact surface gets to 100 degrees before the top of the block) balances out that the copper block loses heat to the surrounding area via it’s side walls.

    • Contramuffin@lemmy.worldEnglish
      48·
      25 days ago

      Was intrigued, so made a simulation to figure it out.

      TLDR: 592.2 seconds, or 9 minutes and 52.2 seconds. Very similar to the other comment - it appears temperature differentials and heat loss to the air have opposite effects on thermal throttle time and mostly cancel themselves out. For the most part, heat transfer and heat loss appear to affect the thermal throttle time less than the sheer heat mass of the block by several multiples

      Assumptions:

      • Copper’s heat conductivity is 400 W/m-K, and specific heat is 0.4 J/g-K, and density is 9000 kg/m^3, and these values do not change over the range of temperatures
      • Air’s heat transfer coefficient is 20 W/m^2-K and does not change over the range of temperatures
      • The surrounding air does not change in temperature and remains at room temperature (25 C)
      • The input wattage is actually 120 W and not just random marketing bullshit
      • The copper block’s size is 4 cm x 4 cm x 16 cm (same as other comment)
      • The temperature within the copper block differs only by the vertical axis; it is assumed that temperature does not change if you move horizontally into the block

      Modeling conditions:

      • The block is sliced into 100 equally-sized slices, stacked vertically.
      • Each slice starts off with a temperature of 25 C
      • 120 W is input directly into the bottom slice
      • Heat transfer is modeled between each slice
      • Heat loss into the air is modeled for each slice (top slice has more heat loss due to more contact with the air)
      • Temperature changes are calculated per millisecond
      • Final time is calculated by the total number of milliseconds it takes for the bottom slice to reach a temperature greater than 100 C

      Fun facts I found from playing around with the model:

      • According to this model, at the time that the CPU thermal throttles, the top of the block should be 85 C
      • If we assume instantaneous heat transfer, time to thermal throttle goes up to 703 seconds (11 minutes and 43 seconds). Difference is about 2 minutes.
      • If we assume no heat loss to the air, time to thermal throttle goes down to 500.0 seconds (8 minutes and 20 seconds). Difference is about 1.5 minutes.
      • The copper block should be able to prevent throttling as long as the CPU remains idle (30W for AMD CPU’s). The CPU should cap out at around 82-83 C.
      • The copper block can prevent thermal throttling for a 170 W CPU for 368.1 seconds, or 6 minutes and 8.1 seconds
    • rockSlayer@lemmy.blahaj.zoneEnglish
      69·
      26 days ago

      But only 3-5 diamonds are generated per chunk, requires an iron pickaxe, and usually doesn’t start appearing regularly until Y level 14.

      Meanwhile copper can have up to 16 veins of copper per chunk, requires a stone pickaxe, and appears most frequently at Y=48.

      Copper is clearly more accessible for making ore blocks.

      Wait a sec, this isn’t [email protected]

    • Zachariah@lemmy.worldEnglish
      10·
      26 days ago

      with the way prices are going, carbon based heat dissipation may become the preferred option

      how pretty would it be if it was a tree-like crystal structure

        • SCmSTR@lemmy.blahaj.zoneEnglish
          6·
          25 days ago

          Watts per milliKelvin? I wouldn’t think that would be a form of thermal capacity OR thermal dissipation, which is why I asked

          Edit:

          Looked it up…

          Apparently it’s “watt per meter-kelvin”, a/(the?) measurement of thermal conductivity.

          Per Wikipedia ( https://en.wikipedia.org/wiki/Thermal_conductivity_and_resistivity ):

          The thermal conductivity of a material is a measure of its ability to conduct heat. It is commonly denoted by k {\displaystyle k}, λ {\displaystyle \lambda }, or κ {\displaystyle \kappa } and, in SI units, is measured in W·m−1·K−1. It quantifies the proportionality between the heat flux (heat flow rate per unit area, W·m−2) and the temperature gradient (K·m−1) in the direction of heat transport.[1] The reciprocal of thermal conductivity is called thermal resistivity.

          Materials with high thermal conductivity transfer heat more efficiently than those with low thermal conductivity. Heat transport can arise from different microscopic mechanisms: In metals, thermal conductivity is typically dominated by free electrons, whereas in dielectric materials such as diamond it is largely due to lattice vibrations. Materials with high thermal conductivity are used in heat sink applications, while materials with low thermal conductivity, such as mineral wool or Styrofoam, are used for thermal insulation.