Demonstration and test of 35 fans

Details of our test participants

As indicated above, two measurements were made in the test. We tried to get information about noise on the one hand and air transport on the other.

Noise measurement

Noise measurement seemed problematic, as high background noise made it difficult to measure low noise emissions from fans. Because of this, we came up with an interesting method, which later turned out to be its flaws.

The measurement was performed in a completely closed 30 × 30 × 20 cardboard box. The fans blew the air in the opposite direction to the noise meter, so the wind noise had less of an effect on the measurement. The propellers were, of course, placed at the same distance from the instrument head.

The disadvantage of the measurement was that due to the small space, the generated noise was much amplified, but it was precisely because of this that relevant differences could be observed. Another advantage of the box was that it brilliantly conducted the vibration, so the balancing flaws also came out. The latter fact is what is difficult to measure on a table. Although we can feel the vibration with our hands, if we place the fan on the table top, we will experience a little humming in the wrong case, but it would have been difficult to judge which fan vibrates our house. The box helped a lot in this, so we got a slightly more nuanced picture of the products.

When evaluating graphs, it is important to know that the reported data show the relative deviation of the fans, so we can find a zero piece for both graphs. That doesn’t mean that fan had no sound, just that it was the quietest of the pieces measured.

Measuring air transport

To measure air transport, we rented a wind wheel anemometer from the instrument rental of the Hungarian Academy of Sciences. So there was no problem with the instrument, all the more so with the construction of the measuring bench. After consultation with the rental specialist, we used a circular profile tube approximately 120 centimeters long, at one end of which we made adapters made of styrofoam and sponge to suit the size of the fans. The length of the tube was essential as a minimum of one meter was recommended to prevent eddies in the tube and to obtain accurate results.

At the beginning of the measurements we got some interesting values, but overall we can say that the obtained numbers are suitable for noticing certain trends by comparing the values ​​given by the manufacturers and the numbers we measured.

We will not go into the results or their explanation now, there will be an opportunity on the side of measuring air transport.

So let the results follow, let's turn!