Vibration Isolation - Air Cooled Chiller

[cvanoverbeke]

We are designing a 6 storey condo in Waterloo, Ontario, Canada and we have specified a 130 ton air cooled screw chiller which is an outdoor unit. We asked the manufacturer for recommendations on isolation to avoid noise complaints in the residential units and this is what the said:

"To reduce vibrations, Id suggest you specify the chiller sit on at rail assembly with spring isolators, and that the structure be very stiff under the chiller (poured concrete pad?) In some cases I know that vibration engineers are consulted for advice."

I came to a similar conclusion but does anyone have any other advise to minimize noise and vibration transmission through the structure. Note. building structure is structural masonry walls with hollow plank floors and roof.

Any feedback would be appreciated.

Cvanoverbeke

 

[SylvestreW]

I'd recommend hiring a proper noise & vibration company. Msg. me if you would like recommendations in the GTA area.

To answer your question:
Saying "put springs and a pad" is strictly accurate, but there's a good bit more than that that goes into proper isolation. You do need to control the stiffness, mass and damping. The springs and the mass of the pad (if required) should be be sized correctly.

To account for noise, you have to ensure your roof is designed appropriate to account for flanking noise. As well, there's airborn noise that may be sufficiently loud to penetrate units.

There's no quick & dirty answer if you are looking for something reliable.

-
Syl.

 

[IRstuff]

Ideally, you'll need to find someone who has experience with the particular equipment, so that they'll know, beforehand, what needs to be done. Sight unseen, there's no knowing how the vibration is manifested, what frequency it is, how robust the equipment itself is, etc.

My itty-bitty 3-ton A/C sits on a pad outside, but the actual noise itself is quite loud.

TTFN

FAQ731-376