watercooling for beginners

Strictly Computers... 

    ...and Computer Peripherals :)


 Today's Topic: Computer Water Cooling

   

 What is Water Cooling

    Computer Water Cooling is the method of removing heat from your cpu (or any source of heat inside your computer hardware: gpu, hard drive, northbridge, etc) with the use of water, and eliminating that heat through a radiator, all in a closed system.  Simple isn't it!  Now, water and electronics don't really like each other, hence the fear of most people about  water cooling.  But as long as the water is in a closed system (no leaks! which is rather easier to achieve than most believe), your  water cooling setup is just as safe as the traditional air-cooled system. 

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Advantage of water cooling

    One short phrase:  Water cooling cools better!!!  Since water extracts heat from any surface better than air, then it follows that that hot surface can be cooled down more effectively by water rather than by air.  For example: a hot frying pan.  Which of the following methods do you think would cool the pan faster and easier: blowing air at it? or pouring water on it?  See?  It's really very simple and logical!  Water cooling offers this advantage than the traditional air cooled system can only dream of.


Components of pc water cooling 

1.  Waterblock:  This is the piece that is in contact with the hot surface.  The purpose of the waterblock (cpu or gpu) is to extract the heat from the CPU (computer's brain, microprocessor, etc) and transfer it to the water.  This is usually a block of metal (copper or silver) with a water channel carved within.  The characteristic of the pc watercooling waterblock that will determine if it can extract heat effectively is as follows:

                a. material:  silver transfers heat from the cpu better and conducts heat to the water better than copper, though this is more expensive.  Copper is the standard material that is used in most waterblocks today.  It is also less corrosive than aluminum.   Please... don't use aluminum!

                b. surface area in contact with the hot surface:  waterblocks usually have "fins" or "pins" that is in contact directly above the cpu. For diy pc water cooling, these fins and pins may be a little hard to machine.  In my waterblock, i used concentric rings to increase the  surface area above the cpu.  The thinness of the metal interface between the cpu and the water also determines efficiency.  The thinner the better.  At most, the amount of  metal between the cpu and the water should be not more than 3mm.

                c. diameter of water inlet/outlet:  the larger the better.  Larger inlets mean more water flow,  hence, more heat removed from the cpu. Standard inlet diameter is 1/2", though 3/8" is not too bad at all. The picture below shows my waterblock directly above the cpu inside my pc

Other concepts: waterloading and turbulence:  

            Water turbulence over the cpu is induced by the fins or pins structure mentioned above.  It is also induced by altering the shape or structure of the inlet (this is the basis of the "impingement" design which as the name implies, impinges the water going  into the inlet and induce turbulence).  Turbulent water sorts of extracts the heat more effectively than smooth laminar flowing water.   Waterloading refers to the amount of water present inside the waterblock at one point in time.  More waterloading in your                                    water cooling system may increase the baseline temperature of your waterblock, making heat  transfer inefficient.  The waterblock should be designed such that water gets in quick, passes  over the cpu area quick, extract heat efficiently, and get out of the waterblock quickly as well.  To see the different waterblock designs and how they perform, try this link:

PC Water cooling waterblocks
 

2. Pump:  The pump is the heart of your pc watercooling system.  You can usually buy hobby pumps in your local hobby shop or aqua pet stores.  Pump performance is usually measured in two parameters: the flow rate and the head.  The flow rate as the term implies measure the amount of water that it can pump per unit time.  The standard is around >80 gallons per hour.  The "head" is the capacity of the pump to shoot water in a vertical column.  To grasp this, imagine a fountain.  A fountain shooting water 5 feet above the ground has a 5 feet head.  Simple!  The pump that you'll choose should have a head equal to 2x the height of your computer casing.  So the ideal head of a pump should be around 4 feet.  So, would I have a guaranteed performance if I choose the most powerful pump I can afford? Think again. Powerful pumps with higher flow rates (over 1000gph) usually produce a lot of heat, which will be introduced in your system, so this is not advisable.  The pump inlet and outlet should match the diameter of your tubings, waterblock and radiator inlet/outlet.

    You can check out the different waterpumps here (no endorsement to buy, though): directron.com 

3. Water reservoir:  Some water cooling experts make do without a reservoir but for beginners and DIYers, I recommend using one for your watercooling rig.  The reservoir is there to eliminate air and bubbles in the system which can affect heat transference.  The picture below shows a plastic jug modded and sealed to fit the intake of the pump.  You can put your reservoir inside or outside of the pc case.

4. Tubings:  I only have one recommendation.  Tubings should not kink!  Kinks limit waterflow and put a heavy strain on your pump!  So invest in quality tubings (tygon, clearflex, masterklear, etc).

5. Pc radiator/fan assembly:  The radiator and fan eliminates the heat generated by your system (main heat source inside your pc: waterblocks on cpu, gpu, etc.;  other heat sources: heat of your pump and ambient heat).  There are many types of rads made specifically for computer watercooling that are available but here are the most important points:

    a. It should be made of no less than copper!  Aluminum radiators tend to corrode, and has a poor thermal conductance.

    b. Single pass multi layered radiators are more effective than double or multipass radiators.  An example of single pass radiator is the car radiator (but hey, don't use this ok?), or the black ice x-flow.  Classic black ice radiators are double pass.

    c. Radiator size is directly proportional to  heat dissipation. Theoretically, the larger the radiator the better!

    d. The higher the fin density (number of fins per unit space) the more powerful the fan you'll need to use

    d. Fans can suck or blow air to the radiator.  But whichever you use, fans should be placed 3-4cms away from the radiator with a "shroud", so that air can pass through the entire surface of the radiator, and therefore aerate the entire fin population.  If you install the fans right in front or behind the radiator, there are areas in the rad (especially the middle portion) that will not receive airflow.  This is not maximizing heat dissipation at all!

    To see an actual testing of different radiators, see this link (pdf): Water cooling Radiators 

   

Setting Up Your Computer Water Cooling System