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| − | == Additional Sections of Air Cooling ==
| + | '''What is the purpose of a case fan?''' |
| − | * [[Airflow]]
| + | To supply a flow of air through the cabinet - usually from front to back. |
| | + | Common recommendations would be front/low intake, rear/high exhaust. |
| | + | The fresh air flowing through the case cools many components that may overheat in an enclosed area. |
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| − | == Air Cooling - Background ==
| + | '''What is a noisy case fan?''' |
| | + | A fan noise of around 30db is considered to be bearable. Louder is usually annoying. |
| | + | Smaller fans need to spin faster to generate the same airflow as larger fans , and are therefore usually louder. |
| | + | Delta Extreme TFB1212GHE are generally considered to be the noisiest. They can be upto 65db depending on fan grills etc. |
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| − | Many, many years ago, when Bill gates said 640KB would be the most amount of storage anyone one person would ever need, CPU's (Central Processing Units) were quite a fair whack slower and this meant that they generally ran fairly cool. Cool enough to get by with a small passive heatsink, or at the very most, a small HSF (Heat Sink and Fan). Some early processors ran completely free of heatsinks altogether!
| + | '''What is an HSF?''' |
| | + | A HSF is a Heatsink and Fan combination. They are generally found on CPU's and sometimes on chipsets. |
| | + | The heatsink is a metal block which makes contact with a heat-generating processor. This block usually has radiating fins, enabling air to cool it and in turn the chip it is resting on. |
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| − | Modern computers nowadays produce appreciably greater amounts of heat, with certain architectures reaching peak wattages of up to 130watts. Furthermore, when a cpu is 'overclocked' (that is, it is run at a speed greater than the speed at which it usually runs at) the heat also rises as more and more voltage is squeezed in in order to extract the maximum speed of any given chip.
| + | '''What's an average temperature range?''' |
| | + | That all depends on what's inside your computer. It varies, although the safe range is considered to be below 65 degrees. Once it passes 65 degrees, you know your air cooling isn't working properly. Some beasty systems can function with air cooling and stay at ~40-45 degrees, depending on fan placement. |
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| − | == Which Materials? ==
| + | More information can be found in the general [[Air-Cooling]] section. |
| − | The basic purpose of a heatsink is to remove heat from the CPU. Therefore, metals with good heat transfer properties are ideal for use in heatsinks. Heat transfer (thermal conductivity) is measured in W/m-K (watts per metre per degree Kelvin). This relates to how well a metal can absorb and transfer heat within itself. Different metals conduct heat differently. In the case of most metals, electrons are shared as members of a collective ‘whole’ in which they float rather freely from one atom to the next. The more easily these electrons can move through the atoms, the better the metal will conduct heat. Here is a table of values for some materials:
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| − | <table border="1">
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| − | <tr><td>'''Material Name'''</td><td>'''Thermal Conductivity (W/M-K)'''</td></tr>
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| − | <tr><td>Copper</td><td>393.7</td></tr>
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| − | <tr><td>Aluminium</td><td>216.5</td></tr>
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| − | <tr><td>Silver</td><td>417.3</td></tr>
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| − | <tr><td>Gold</td><td>291.3</td></tr>
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| − | <tr><td>Diamond</td><td>Up to 2000+, depending upon purity.</td></tr>
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| − | </table>
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| − | Most manufacturers have taken to using aluminium mostly in their heatsinks because it’s cheap and easy to machine. Given an equivilent mass of copper and aluminium, the aluminium design would win, due to the vast difference between the two metals respective densities (8920Kg/m³ and 2700Kg/m³ for copper and aluminium). Copper is also more expensive, and much more difficult to machine; hence the reason why aluminium heatsinks are cheaper than their copper equivilents.
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| − | Air is a rather poor conductor and holder of heat (~0.0262 W/m-K (@ 100KPa) and ~0.001 J/m³K respectivly) that’s why we normally see fans on heatsinks, to push as much (or enough for the noise concious) air through as possible. | + | |
| − | Another important thing is surface area. Some use lots of fins, some use pins that look like screws and some are just roughened all in the name of increased surface area for the heat to be transferred to the air.
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| − | == Adding Air Cooling ==
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| − | The addition of moving air to an otherwise passively cooled system is always beneficial. In a passively cooled system (ie - a system where there is no forced moving air. Forced air being air that is continually moved by a source) heat is transferred from a heatsource to the heatsink and then to the surrounding air. This can take time which is not beneficial for componentry that generates alot of heat quickly. In addition to this, once the heat has transferred from the heatsink to the surrounding air; there is no movement of air. This means the transfer of heat occurs from air particle to air particle which is a very detrimental for the system (Air has a specific heat capacity of around 1-1.5 dependant on condtitions) which means the system heats up very quickly. This is where the addition of fans come in, fans can be used to aid the removal of heat from the heatsink and the removal of heat from the entire system.
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| − | The use of fans on heatsinks helps as it blows/sucks (depending upon fan configuration) away from the heatsink drawing air across the heatsink surface, removing heat from the heatsink and moving the air away from it. The use of correct system cooling and heatsink and fan configuration can lead to a relatively cool and stable system. A perfect mix of the conventional and non-conventional methods of cooling would be to remove the "stock grills" or "factory grills" already present on the case to allow additional airflow through somewhat restricted areas. It is, of course, advisable to install other grills and/or finger guards once these have been removed for safety purposes.
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| − | In addition to this, fans operate at different RPM's which can greatly alter the amount of noise (in dbA) that it puts out. Generally, the rule of thumb is: the more airflow the fan puts out, the louder it is. Also, the larger the fan (that is, fan blade diameter wise) it will spin at a lower RPM to push the same amount of air (measured in CFM (Cubic Feet per Minute) that a smaller fan would have to spin to push the same amount. There are many combinations that you can choose. Some people prefer performance at any cost and will buy high CFM fans, regardless of the noise put out (there are fans that can push 200cfm), while some people will buy lower CFM fans which run almost silently and then there are others that fall in between and get a bit of both. It is largely dependant upon the user.
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| − | The conventional method of adding additional air cooling is to install one or more additional fans in pre-formed/cut areas. Of course the non-conventional method would be the installation of fans in a non-default place. This would usually involve the removing of metal, rebuilding and/or reconstructing parts of the chasis, bezel and/or side panels, depending on the placement of the fan. This will allow the removal of hot air and the addition of 'cold' air to your system, provided it has been set up correctly.
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| − | == Filters ==
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| − | The use of filters in air-cooling systems is to stop dust from seeping into the inside of the case. As dust can have adverse affects on systems (the worst side effect being an increase in temperature) these filters are used more and more frequently. Many more expensive cases (EG: Thermaltake Brand cases) have started to encorporate filters into their design.
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| − | Dust filters should be checked regularly and cleaned as needed.
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