What is the effect of scaling down a heat exchanger?

In summary, the article discusses the benefits of scaling down heat exchangers, as it reduces the distance the heat has to travel and increases heat flow. However, there are other factors to consider, such as decreased heat capacity and thermal conductance at smaller scales. The advantage of decreased distance may outweigh the disadvantage of lower heat capacity, but it also depends on how other properties scale. The diagram shows that the proposal aims to reduce the thermal resistance between the die and coolant by fitting the required surface area into a smaller space.
  • #1
JessEE92
1
0
According to this article, it is beneficial to scale down heat exchangers due to the decreased distance the heat has to travel, and therefore the decreased thermal resistance and increased heat flow.

"the best way to remove heat from a CPU is to minimize the distance heat must travel from a CPU's hotspot to the heat collector before it's carried away"

However what confuses me is that their are more things that affect heat flow than travel distance, and to me it seems that scaling down the heat exchanger to micro and nano scales would be detrimental to performance. For example the heat capacitance of the exchanger will go down with its reduced mass, therefore it will get to much hotter temperatures while removing smaller amounts of energy. The thermal conductance of silicon decreases for hotter temperatures so this will decrease heat flow.

It all depends on how the properties scale. Will the advantage of decreased travel distance outweigh the disadvantage of lower heat capacity as you scale down?

My second question is: Are there other relevant properties (thermal or otherwise) that are effected by scaling heat exchangers?

Here is a diagram of the heat exchanger in question:

figure_02.gif
 
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  • #2
What they are doing is reducing the thermal resistance between the die and the coolant. That is made up of two parts in series...

1) Thermal resistance between die and heat collector.
2) Thermal resistance between heat collector and coolant.

This proposal reduces 2).

They aren't necessarily reducing the surface area but are fitting the required surface area into a smaller space.
 

Related to What is the effect of scaling down a heat exchanger?

1. How does scaling down a heat exchanger affect its efficiency?

Scaling down a heat exchanger can actually improve its efficiency. This is because a smaller heat exchanger has a larger surface area to volume ratio, allowing for more efficient heat transfer.

2. Does scaling down a heat exchanger impact its heat transfer rate?

Yes, scaling down a heat exchanger can impact its heat transfer rate. Generally, a smaller heat exchanger will have a lower heat transfer rate compared to a larger one. This is because the smaller size can lead to a decrease in flow rate and a decrease in available surface area for heat exchange.

3. Is there a limit to how much a heat exchanger can be scaled down?

Yes, there is a limit to how much a heat exchanger can be scaled down. This is because as the size decreases, the surface area to volume ratio increases, leading to higher pressure drop and flow resistance. At a certain point, the pressure drop becomes too high and the heat exchanger becomes inefficient.

4. How does scaling down a heat exchanger affect its cost?

Scaling down a heat exchanger can lead to a decrease in cost. This is because smaller heat exchangers require less material and have lower manufacturing and installation costs. However, there may be a trade-off between cost and efficiency, as a smaller heat exchanger may not be as effective as a larger one.

5. Can scaling down a heat exchanger impact its durability?

Yes, scaling down a heat exchanger can impact its durability. A smaller heat exchanger may have thinner walls and be more prone to corrosion or damage. It is important to consider the operating conditions and materials used when scaling down a heat exchanger to ensure its durability and longevity.

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