Evaporator Fan Comparison

Hi guys,

I have a question in regard to the selection of the evaporator fan. Currently, we are using the Ziehl-ebm 350mm, axial flow fan, however we are now considering the alternative fan offered by Rotomatika, 350mm because of the cheaper price they offer. Rotomatika also claims that their performance was better than Ziehl during their manufacture testing. This all sounds good right?

Unfortunately, during our independent lab testing, we found that Ziehl was a significant better fan for our own coil blocks (6 Fins per inch) and the perforamnce was better by around 7-8%. So, I need some advice on this, should I go for what the Rotomatika clamied or should I trust on our lab test as our lab test might not be very accurate.

Also, I would like to hear people who have actually come across with Rotomatika and how did you guys think about it ?

Rotomatika : R11-axial Ventilator 350
Ziehl-ebm : s4E350-AP06-48

Thanks !

pcle

What were the specifications on which the manufacturers based their ratings? One fan may perform better at a given static pressure than another, but be worse at a different static pressure. Your coil block may present too high a static pressure for the cheaper fan to perform well.

I would retest.

Hi RogGoetsch,

Thank you for the reply and here are the manufacture's ratings;

Rotomatika measured their fan based on the volume air flow with quadrant inlet nozzle (ac to standard ISO5801) at 230V/50Hz. Application type, 4 rows, 10 Fins per inch, total fin legth - 90mm and the pressure drop: cca. 50 Pa @ 2400m^3/h.

Our measurement was based on the same fan rating of 230V/50Hz but with three different coil blocks attached. (1), 2 rows, 6 fins per inch, (2), 3 rows, 10 fins per inch and (3), 6 rows, 6 fins per inch.

I believe your suggestion is probably correct, however we did try with 3 different coil size blocks and the result still suggests that Ziehl performed better than Rotomatika. One thing we did find was that at higher resitance of the coil blocks, the Rotomatika is almost on the par with the Ziehl.

ps. Yes, we will do a retest as we have requested another sample fan from Rotomatika. Thanks for this advice.

Pcle