What Keeps Computers from Frying up!!

Imagine working on your laptop aggressively when suddenly it starts having a meltdown due to excessive heat. The reason this doesn’t happen is because of the magic of thermal transfer and the thermodynamics – that heat moves from a region of higher temperature to an area of lower temperature. While you may be aware of the fans on your laptops or computers, several other technologies make use of our very own heat transmission techniques, evolving day by day to make them more efficient and Cool! 😛

  1. Heat Sinks
    1. One possible solution is heat sinks, a passive device with sizeable thermal capacity, and with a large surface area relative to its volume. They are usually made of a metal with high thermal conductivity such as aluminum or copper and incorporate fins to increase surface area. The heat from a relatively smaller component is transferred to the more massive heatsink as the equilibrium temperature of the element plus heatsink is much lower than the component’s alone would be. Heat then is carried away from the heatsink by convective or fan-forced airflow, with the larger surface increasing the rate of heat loss due to conduction, convection, and, to some extent, radiation.
  2. Liquid Cooling
    1. Liquid Cooling for PCs is identical to the cooling systems present in automobiles with the refrigerant beings circulated by water pumps through the watertight water blocks mounted on CPUs, GPUs, and other additional components. Water blocks are pieces of heat conductive metals with hollow tubes and channels, and their flat surfaces sit directly on top of the units to cool. Although it may seem counterintuitive to put liquids near electrical components, water or liquids used as coolants do a much better job than air cooling because of their higher specific heat capacity and thermal conductivity.
  3. Liquid Immersion Cooling
    1. As the name suggests, it is the practice of submerging computer components into thermally but not electrically conductive coolants, so that it does not hinder the working of the regular operation of the element. Depending on the properties of the coolants, we can classify Liquid Immersion Cooling as :
      1. Single Phase Immersion Cooling, where the liquid never changes its phase, We remove the heat from it by pumping it to some other heat exchanger or using an open bath system which has a liquid-air interface for the liquid to lose energy.
      2. Two-Phase Immersion Cooling, where the liquid, having a low boiling point, boils and exists is both liquid and gaseous phases. A condenser cools the gaseous phase to liquid again as it is cooler than the saturation temperature of the fluid. This process wonderfully utilizes the concept of latent heat, the energy needed for the change of state, for efficient cooling of the systems.
  4. Thermal Compounds
    1. Perfectly flat surfaces in contact help you achieve optimal cooling. This is largely impossible, and they usually exist microscopic air gaps, which are especially common due to the mass production of these devices. Thermal conductivity of air is much less than metal. So, if the gap gets filled, thermal contact can be improved significantly. Thus, making the cooling much more effective.The problem is finding the desired compound with desired thermal properties and we are able to fit it in those air gaps. The use of thermal compounds is almost universal when dissipating significant amounts of heat.
  5. Vapour Chambers
    1. Standard heat pipes only transfer heat along their axes, and this makes Vapour Chambers different from them. Vapour chambers are planar heat pipes that can spread heat in two dimensions and hence allow faster cooling, typically used when high heat flux is applied to a relatively small evaporative area. The vapor flows through the chamber, creating an isothermal heat spreader and condenses on the condenser surface where it is much easier to remove the heat by natural convection or cooling.

While this is not an exhaustive list, it provides a great idea about how the concepts that we study in our fluids and thermodynamics classes are applied to make our lives easier.

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