Yate Loon D12SL-12 120mm Case Fan Review Page: 1
Introduction
 
I'd like to wager that there aren't many people who aren't familiar with the name Yate Loon. The Taiwanese based manufacturer of DC fans is very popular within the realms of the PC enthusiast, and more accurately, the water-cooling enthusiast.
 
Today I have been given the opportunity of reviewing some Yate Loon D12SL-12 120mm Fans. Will these fans deliver more air flow and an increase in static pressure which should make them the perfect candidates for heat sink and radiator cooling duties?
 
Yate Loon D12SL-12
 
Let's move on and have a look at the Yate Loon D12SL-12's specifications....
 
 
Specifications
 
The Yate Loon D12SL-12 specifications were unashamedly taken from the products webpage.
 
Model: D12SL-12
Dimensions:120x120x25mm
Rated Voltage: 12 Volts
Operation Voltage: 6.5~13.8 Volts
Input current: 0.30 Amp Max
Operation temperature: -10 to +65 C
Storage temperature: -40 to +70 C
RPM: 1350 +/- 10%
CFM: 47
dB: 28

The specifications look par for the field for the Yate Loon D12SL-12, although I would have preferred to see a little more information on the fans like MTBF and bearing type.


Yate Loon D12SL-12 120mm Case Fan Review Page: 2
Packaging
 
The samples that I received from Aqua-Pcs were obviously OEM, and as such they forego any inclusion of advertising or  adaptors that typically come with retail units. However, the packaging is sufficient enough to prevent any damage during transit.
 
Yate Loon packaging_1 Yate Loon packaging_2
Yate Loon packaging_3
 
 
A Closer Look
 
The Yate Loon D12SL-12 are a remarkably nice looking and well constructed fan. The fan itself comes with a standard 3-pin connector.
 
Yate Loon D12SL-12 front Yate Loon D12SL-12 rear
 
 
Yate Loon D12SL-12 side on Yate Loon D12SL-12 reverse side on
 


Yate Loon D12SL-12 120mm Case Fan Review Page: 3
Static Pressure Theory
 
I thought it would be pertinent to run over some basic theory in relation to static pressure and its benefits, as all fans are not created equal. Furthermore; I hope that by covering the basics it will help the newer members grasp what we are trying to achieve a little easier. So what is Static Pressure?

Static Pressure is usually stated either in inches of water (inH2O) or in millimeters of water (mmH2O). It is essentially a measure of the differential air pressure between the air pressures inside an application vs ambient air pressure outside of an application, which for airflow calculation purposes is usually 0 (zero). There is an inverse relationship between airflow and static pressure. As the pressure differential rises, airflow drops.

Ok so that makes sense so far doesn't it? Essentially static pressure, or more accurately the measure of it, is the difference in pressure. Because we are looking at utilising higher static pressure fans for possible heat sink or radiator cooling work, the static pressure differential then becomes the difference in air pressure on the inlet and exhaust of the chosen application. We can think of the differing pressures as positive (absolute pressure of the fan) and negative pressure (pressure drop experienced after heat sink/exchanger). I have included a few diagrams to help get the point across:
 
Equal pressure Negative Pressure
 
The first image (above left) is that of equal pressure, where the pressure on the outside of a case is equal to that on the inside...and not an optimal solution for cooling. The second image illustrates negative pressure where the pressure inside the case is less than the outside pressure. Negative pressure allows air to enter the case at the right direction and speed and is needed for efficient cooling.

Now the principal is similar when it comes to fan static pressure, which is illustrated by the image below:
 
Static Pressure Diagram
 
So by now you may be asking "What the hell does this have to do with fans?". Ok, as air flows through fin configurations (either on a heat sink or heat exchanger), the small openings constrict the flow, creating a pressure drop. Because air flow velocity is directly proportional to air flow volume and proportional to the static pressure drop, heat sinks and heat exchangers require a higher flow velocity pressure to move a given volume of air through a heat sink. To increase the velocity, an increase in fan power is usually necessary to maintain the same mass flow of air through the heat sink.

Ok so now that we understand a little more about static pressure theory, let's head over the page to see how we're going to test the Yate Loon D12SL-12's.


Yate Loon D12SL-12 120mm Case Fan Review Page: 4
Test Methodology
 
In order to accurately test the Yate Loon D12SL-12 fan I have decided to review its performance from two perspectives:

* Static Pressure and air flow
* Cooling ability

The Yate Loon D12SL-12  will be compared against Noctua's latest 120mm case fan offering - the NF-P12.
 
#Note: The equipment that I have used for the static pressure testing phase of this review is not, and never will be equal to the testing facilities that case fan manufacturers employ. The static pressure results here should be taken as an indication, and I'd like to think of it as a pretty good indication, but once again professional testing laboratories win out over a kitchen table simulation every time.

Static Pressure and Air Flow

In order to test the static pressure of the Yate Loon D12SL-12 and Noctua NF-P12 fans I constructed an air-tight test chamber which would allow me to physically assess how much additional static pressure the fan provided. The total approximate volume of the test chamber was 221.18 cubic inches. A digital Manometer was used to record the positive static pressure emitted by the fans. A Pito Tube from the digital Manometer was inserted into the test chamber out of the wind stream created by the fan, in order to prevent air velocity from corrupting the Manometer readings. Prior to testing the Digital Manometer was calibrated according to manufacturers specifications, in order to accurately read the resultant static pressure according to current atmospheric pressure.
 
Static Pressure test setup Closeup of heater-core
 
The Yate Loon and Noctua fans were then forced to pass a volume of air through a Toyaota Camry heater core, which will act as the radiator. The heater core has a fin count of approximately 84 fins/square inch and as such should provide more than enough resistance for validatable results. All static pressure readings were taken whilst the fans were running at 12v, and 3 x 60 second samplings were taken each time via RS232 software and uploaded to my computer via the serial port.

#Note: The digital Manometer that I have used for todays testing is accurate to +/- 2%. However, the digital readout only records to 1 decimal place which makes the results relative in the grand scheme of things, but fails to provide an exact amount of static pressure i.e to two or more decimal places. Currently this is all my review budget allows for at the moment, but I will be upgrading my Manometer in the near future to a better model. So please bear in mind that when you see the static pressure graphs on the next page, that when a fan shows '0' static pressure it is actually between 0.0 cmH20 and 0.099 cmH20.

The Yate Loon and Noctua fans were tested for free air flow capacity using a calibratable digital Anemometer, upon which they were allowed to run at 5v, 7v and 12v respectively. I have chosen to test the fans at these three voltages due to the increasing number of people undervolting fans in the name of silence. Power for the testing phase was provided by a variable power supply, and the voltages checked using a digital test meter. The Yate Loon and Noctua fans were also tested for air flow when installed on the airtight test chamber by using the calibratable digital Anemometer to record the air flow after it had passed through the cooling fins of the radiator.
 
variable power supply and multimeter
 
 
Cooling ability

In order to assess the actual cooling performance of the Yate Loon and Noctua fans I have set up a simple water-cooling loop comprising of the following items:

* Alphacool X2 Bold CPU Water Block
* Laing DDC Pro pump with OCLabs Top and 1/2" EK High-Tail barbs
* 1/2" XSPC clear tubing
* Intel E6600 CPU
* Variable Power Supply
* Digital volt meter
* Aerocool Gatewatch rheobus with digital display
* Toyota Camry heater core with custom made air tight tin shroud
 
Cooling test setup Thermal probes
 
I have set up two thermal probes on the inlet and outlet of the heater core and temperatures will be monitored on a digital rheobus so that we can see just how well the extra static pressure effects water temperature within the radiator. All fans will be run at 7v and 12v and the resultant temperatures recorded. CPU load will be obtained by running 1 x instance of Stress Prime 2004. Temperatures will not be recorded until they stabilise for each fan tested. Ambient temperature at the time of testing was 26.3 Deg Celcius.

Let's go testing....


Yate Loon D12SL-12 120mm Case Fan Review Page: 5
Testing
 
You can see from the included graph that the Noctua NF-P12 fan provides considerably more static pressure than the Yate Loon D12SL-12. Please bear in mind that my ghetto testing equipment only provides an indication of static pressure, and according to the results below the D12SL-12 provided static pressure between 0 - 0.09 cmH2O and the NF-P12 - 0.199 cmH2O.
 
Static pressure chart
 
You can see from the free air flow chart that the NF-P12 facilitates slightly more airflow than the Yate Loon D12SL-12, even though the NF-P12 has a slighly lower rotational speed than the D12SL-12.
 
 Free Air Performance
 
The D12SL-12 doesn't cope as well with the radiator testing, mainly due to its inability to generate more static pressure. However I was surprised at the results that it managed to muster regardless.
 
Radiator Air Flow
 
Installing the D12SL-12 and NF-P12 120mm fans on the radiator for our cooling tests yielded some slightly predictable, but  interesting results. The NF-P12 certainly has the goods and it performs well whilst being almost totally quiet. The Yate Loon D12SL-12 on the other hand is slightly noisier than the the Noctua @12v, but at 7v they sound pretty much on par.
 
D12SL-12 vs Noctua NF-P12 Temperature Comparison
Voltage (v)7v  7vΔT12v12vΔT
Radiator probe configinout inout 
Yate Loon D12SL-1237.534.92.637.134.22.9
Noctua NF-P1234.331.6 2.734.130.93.2


Yate Loon D12SL-12 120mm Case Fan Review Page: 6
Conclusion
 
So how well did the Yate Loon D12SL-12 120mm Fan perform in todays review?
 
The D12SL-12 whilst not being as quiet as the Noctua NF-P12 is certainly very quiet and would compliment  any water-cooling setup. To be honest, I can see why the Yate Loon 120mm fan range has become so popular with the water-cooling enthusiasts. They are a great, no-frills fan which perform very well. But the absolute kicker here is the price! For a measly £3.99 (VAT Exclusive) you can own one of these, and you can own almost 4 for the price that you would pay for 1 Noctua NF-P12. These fans are an absolute steal.
 
Aqua-Pcs logo
 
The Good
• Excellent value
• Good performance
• Quiet
• Quality
 
The Mediocre
• Slightly noisier than the NF-P12 @12v
 
The Bad
• Nothing to report
 
OC3D Value For Money Award
 
A big thanks to Aqua-Pcs for supplying the review samples.
 
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