Nature, design and trivial stuff.

Can't see the wood for the trees

Yesterday I had my first 'milestone' presentation with my supervisor, Torben Lenau. As part of the problem statement, it was necessary to set out a time line of activities which included milestone presentations where reached goals are presented, discussions are had, changes are made and the supervisor can keep up with my activities. It can also mean that the direction of the thesis can change...

Micro cooling electronics

CPU pre-cooler install (image credit)

I have been researching micro cooling technologies used in electronics, specifically CPU (computational processing unit) devices. Newer devices are getting smaller and more powerful but the draw back is that they are giving out more heat. Heat flux is the rate of heat energy transfer through a surface and used as a measure of CPU performance. A CPU such as a Pentium 4 processor (used in home PCs and laptops) can emit heats of up to 115 W/cm² (where W is Watts or Joules per second). There are devices producing up to 150 W/cm² in computers and in other applications (hybrid cars, defence systems) researchers are looking at heat fluxes of up to 1000 W/cm²! Researchers like Issam Mudawar at Purdue university and Meilin Liu at Georgia Intitute of Technology (and many others) have been trying to solve the problem of over heating electronics in domestic, industrial, aviation and space systems.

Over the last 5 weeks, I have come to realise that the issue of cooling electronics is a huge area. There are a number of different techniques used including heat sinks (passive and fan assisted), liquid cooling, refrigeration, thermoelectric cooling, single and two phase changing liquids (using latent heat effects) and all of these are huge subjects in themselves. Many research papers have been written regarding the optimisation of geometries, fluid flow models, heat transfer and thermodynamics. Some observers believe it is now time to implement innovative and novel solutions which can solve the problem rather than focusing on theory, which can be time consuming in a world where technology is moving at such a fast pace. I felt that by applying some biomimetic inspired elements to a certain cooling process, there might be some benefits. This was a wrong approach.

Focus

Silicon wafer with lizard inspired geometry

The reason I wanted to write a thesis on 'Thorny Devil lizard inspired cooling' was to implement my previous findings in a cooling solution principal. At the milestone, my supervisor reminded me of this. Although my research was interesting and worthwhile for a holistic overview of micro cooling technology, it was taking on too much. It was necessary to focus on the interesting capillary action that takes place on this lizard inspired surface and how this passive action could be used in a cooling solution. It does not have to be limited to CPU cooling but a concept needs to be proven to work. For our next meeting (Tuesday 30 April), my tasks are to quantify:

1. How to use capillary action to increase surface area (and promote heat transfer) and guide fluid around a system to improve cooling.
2. How much heat are we talking about and how efficient a system like this could be.