The introduction to this article has been rewritten several times. The original versions resorted to describing the adverse events that caused the long-announced fan testing to be so dramatically delayed. But the text was always dreadfully boring… the important thing is that everything managed to make it to the start. But before the starting gun, come take a thorough walk around the track where the measurements will take place.
Measuring the intensity (and power draw) of lighting
Modern fans often include lighting. This is no longer a “cooling” parameter, but for some users the presence of (A)RGB LEDs is important. Therefore, we also measure how intense this lighting is in our tests. These tests are the only ones that take place externally, outside the wind tunnel.
We record the luminosity of the fans in a chamber with reflective walls. This internal arrangement is important to increase the resolution for us to measure anything at all with lower luminosity fans. But also so that the readings do not blend together and it is obvious which fan is emitting more light and which one less.
The illumination intensity is measured in the horizontal position of the fan, above which is the lux meter sensor (UNI-T UT383S). This is centered on the illumination intensity sensing chamber.
The illumination is controlled via an IR controller and the hue is set to RGB level 255, 255, 255 (white). We record the brightness at maximum and minimum intensity. According to this, you can easily see if the brightness is high enough, but conversely also if the lower level is low enough for you.
In addition to the brightness intensity, we also measure the power draw that it requires. This is again through the shunt, which is between the Gophert CPS-3205 power supply and the (A)RGB LED driver. After this we get a reading of the lighting power draw. In the graphs we show it separately, but also in sum with the motor power draw as the total maximum fan power.
Have you tried PWM controllers other than the Noctua NA-FC1? Does the NA-FC1 offer some advantages over other (often much cheaper) controllers?
We tried our own solution, our own PWM controller. But it was rather clumsy and the only disadvantage of NA-FC1 is that it is not possible to read a numeric value from it. And maybe the fact that it has a narrower rotation range. As long as it is powered by a laboratory power supply, it does not reduce the sensitivity of the exact setting (and what needs to be set can always be fine-tuned in units of mV on the power supply). I have no experience with other off-the-shelf PWM controllers, nor did I know there were any. All PC speed controllers I have used in the past only supported DC control. I have probably the most experience with Scythe Kaze Master Pro and Lamptron Touch. 🙂
Hi,
Could you please clarify the flow in the pull position?
I’m referring to measuring the airflow in a pull fan configuration.
Yes, thanks for asking. Schematically this is the model:
The airflow guide is on the opposite side of the tested fan. This design is the result of several years of research in which we compared different tunnel concepts and in the end we evaluated this design as the most accurate and the most objective. Different tunnels have different problems, for which some fans are relatively advantageous, but others are disadvantageous. This topic is not suitable for a comment below an article, a whole book could be written about it. And we will write it as well, but everything in its time. Some of the wording and details in the methodology are deliberately such that someone cannot adopt it 1:1. We wanted to avoid such a risk, because it would put us at a considerable disadvantage if many things were considered a “good idea” even by someone with significantly better marketing than we have.
But we are slowly approaching the stage when we will be able (our two-year work on tests will not be surpassed :)) to go into details (and also, if I can find the space for it, I would like to revise the overall documentation for the test methodology) and on the basis of the results of our own experiments to analyze in detail why our design is more relevant for the evaluation of fans than the traditional designs with long ducts with a grilled airflow guide. Even a detail such as the orientation of the fan to the tunnel can significantly distort the perspective of the evaluation. When measuring the noise of fans on a tunnel, its walls (tunnel walls), compared to free space, increase the noise of each fan differently. There is a more detailed discussion on this in this thread actually. But these are all things that require reviews of different tunnels with different fans under different conditions to understand sufficiently. We have these data and sooner or later we will certainly process them and publish them in a series of popular-style articles. I can’t promise to do it right away, because it will be a lot of work, which will be commercially inefficient. And serious magazines that want to survive and are based on in-depth reviews don’t have much room for that. But we will certainly get there. It is necessary to start off gently, so that people can understand elementary things/phenomena sufficiently. The design analysis of individual elements in the test tunnels is a more complex topic for the true fan enthusiasts, of which there are only a few, unfortunately. The interest must be always more widespread for the work to make sense financially. With this, we will definitely go financially into the negative, the efficiency in this direction will be low, but we count with it and we have to plan everything properly. Particularly since the series of articles on this subject will be extremely laborious, it is a very demanding topic. Especially if the form of processing is to be understandable even for laymen.
The orientation of the air flow through the tunnel need not interest you at all. With regard to the design of the test tunnel, it is chosen with a view to achieving sufficient laminar flow wherever it is necessary for objective measurements. It has nothing to do with the orientation of the fan on the obstacle. Differences in this respect are shaped primarily by the degree of imperfection of the test system. If someone gets lower airflow on push, it is mainly because the nature of the airflow is more turbulent at the point of dynamic pressure measurement.