Submerged PC Cooling By: Patrick Hague Geoffrey Clark Christopher Fitzgerald Group 11

History of PC Cooling Early personal computers did not require active cooling Increasing demand for computer technology requires cooling improvements Today’s smaller devices require more complex analysis and design for cooling

Cooling Methods In Use Aluminum heat sinks The cumulative energy consumption worldwide of both manufacturing the heat sinks and operating the fans is an estimated 10 9 kW hours per year!

…Other Methods Heat pipes are a very effective method of removing the heat from the surface of the processor Water cooling using water blocks requires the use of a pump and radiator

Objectives Reduce power consumption of system Increase cooling potential Reduced noise pollution

Why Submersion? Lower velocity for heat migration required The ability to remove the heat from the components, and dissipate it in a general location

Enclosure Design Sizing Specifications: 1. Fit inside case with components 2. House all the pc boards 3. Must be water tight 4. Modular design

Enclosure Design (cont.) ¼ inch acrylic enclosure for visibility Vertical cable orientation 3 gallon capacity

Components CPU: AMD Athlon XP = 60 Watts Max GPU: ATI x700 Pro = 33 Watts Full Load Memory, Motherboard = 60 Watts Total Heat Output expected = 153 Watts (safety factor included)

Initial Setup

Designing Heat sink Must dissipate 153 Watts Should fit as cover over the enclosure Cannot interfere with case components Fins must be spaced far enough apart to allow proper natural convection cooling Heat sink must contact fluid

Heat Transfer Analysis Ensure the CPU and GPU temperatures are within specifications. Maintain a stable operating environment, no hot pockets of fluid. Keep the fluid at a temperature relative to a typical air cooled case.

Heat Transfer Solution CPU/GPU Calculations: Enclosure Heat sink Calculations: b + b

CPU/GPU Calculate the base temperature of both CPU and GPU Use extended fin equations in natural convection

Enclosure Heat Sink Use the CPU/GPU fluid temperature as a given Determine the surface area required to dissipate the total 153 Watts

Finished Heat Sink

Results

Conclusions Case can be cooled with passive cooling Power consumption has been reduced by approximately 5 Watts Case is effectively silent

Where to go from here? Commercial applications on larger scale  Server applications have high power density  More fluid yields greater results

Questions? Thank You