Understanding Cooling System Principles of Design
Introduction
This thread serves to help people understand how various cooling systems work and the reasons why; rather than the typical statistically grounded explanations, I prefer to describe the advantages using simple physics. For more on why you want to cool your CPU, perhaps even below ambient, please check out my thread "The Effect of Temperature on your Processor"
Table of contents
A brief introduction
An Introduction to Cooling
Movement of heat
Conduction (flow of heat between two touching materials)
Radiation (Infa-red emissions )-though ignored for simplicity
The laws
dQ/dt is the rate of heat flow
To maximize dQ/dt:
Increase K (conductivity)
Increase A (area)
Increase ∆T (difference in temperature)
Air cooling
Heat moves from CPU to heat-sink, to air
Limited by ∆T
Effectively used in every other cooling application
Improvement of Stock HSF
Increase surface area (A)
Increase thermal conductivity (K)-better material
Heat-pipes, minimize distance
Water Cooling
Effectively increase ∆T
Cold water across CPU (contained inside of a waterblock)
Uses radiator to dissipate heat to air
Limited to super-ambient temperatures
Sub ambient
Thermo-electric couplings (TEC or Peltier)
Refrigeration, phase change
Phase Change-back to physics
Enthalpy (energy)
So what?
Energy ‘consumed’ by the reaction
The energy must come from somewhere (conservation of energy)
The most interesting aspect: liquid to gas transition.
To conclude the theoretical
Speed limited by voltage and resistance (K value)
Voltage limited by temperature
In conclusion, to increase speed we must decrease temperature.
Edited by wcdolphin - 8/8/10 at 12:01pm
Introduction
This thread serves to help people understand how various cooling systems work and the reasons why; rather than the typical statistically grounded explanations, I prefer to describe the advantages using simple physics. For more on why you want to cool your CPU, perhaps even below ambient, please check out my thread "The Effect of Temperature on your Processor"
Table of contents
A brief introduction
An Introduction to Cooling
Movement of heat
Conduction (flow of heat between two touching materials)
Radiation (Infa-red emissions )-though ignored for simplicity
The laws
dQ/dt is the rate of heat flow
To maximize dQ/dt:
Increase K (conductivity)
Increase A (area)
Increase ∆T (difference in temperature)
Air cooling
Heat moves from CPU to heat-sink, to air
Limited by ∆T
Effectively used in every other cooling application
Improvement of Stock HSF
Increase surface area (A)
Increase thermal conductivity (K)-better material
Heat-pipes, minimize distance
Water Cooling
Effectively increase ∆T
Cold water across CPU (contained inside of a waterblock)
Uses radiator to dissipate heat to air
Limited to super-ambient temperatures
Sub ambient
Thermo-electric couplings (TEC or Peltier)
Refrigeration, phase change
Phase Change-back to physics
Enthalpy (energy)
So what?
Energy ‘consumed’ by the reaction
The energy must come from somewhere (conservation of energy)
The most interesting aspect: liquid to gas transition.
To conclude the theoretical
Speed limited by voltage and resistance (K value)
Voltage limited by temperature
In conclusion, to increase speed we must decrease temperature.
Edited by wcdolphin - 8/8/10 at 12:01pm
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