Possible to Adjust Timing and Speed of Rooftop Water Cooler for Air Conditioning System?

You can put a smaller pulley on the motor (or a larger one on the blower) and install a timer on the motor circuit.

Your landlord may not like it though.

I guess that was too late in the day for me to be thinking correctly! I'm definitely sharper in the morning...

Sorry Lyn, of course you were right.

I'll stick with the variable speed drive suggestion though.

Possible, yes, but you would probably reduce the cooling capacity and might damage the unit....so short of replacing the unit with a quieter option...I would check to make sure the unit is operating properly, the fan could be out of balance, or a bearing could be going bad, or a mounting bracket could be loose, or some other problem.....short of that you could try to mask the sound, wear headphones, earplugs, or move to another location, the last option probably the most effective...

Maybe this unit already has a timer on it, but a power failure shifted it by ~12 hours.

Your only recourse is to complain to the landlord, preferably in writing. You can't touch someone else's equipment without getting into trouble. (Maybe he is unaware of the problem.) Talk to the other tenants. If there is more than one complaint, your chances are better.

It seems that this is a repeat of a thread we saw a few months ago. It sounds like nothing has changed and no action has been taken.

I may be mistaken and I don't have time for a search.

"It seems improbable that a system used to remove heat from a building would be working hardest at night."

Could be the chiller is being run at night to cool a storage tank of water or brine to near or below 32°F that's used to supplement system capacity during peak load times the following day.

This enables them to get by with a smaller chiller than would otherwise be required. Since chiller COP is higher and electric rates are lower at night, operating costs can also be reduced.

I find it similarly improbable that a system producing so much vibration would be one also refined to efficiently capitalize on cooling a reservoir during off peak hours.

Even less probable would be the increased investment for supplemental reservoir sized large enough to not only meet excess peak demand but to be large enough that the system works harder during off peak hours that at peak.

Often, neighbors can claim that the same AC unit is noisier at night than during the day while the sound levels are same or even converse.

Regrettably, we don't know what in fact is the difference in sound levels of this chiller between day and night operation, if any.

Off-peak thermal storage is not new and it often pays off: Lower cooling costs

However, noise complaints from neighbors can be a problem and need to be solved.

"Regrettably, we don't know what in fact is the difference in sound levels of this chiller between day and night operation, if any."

If you don't know the difference in sound levels between day and night operation, how do you know that there is ANY difference?

Is a typical adult guraffe taller that a typical zebra? Can you know this without knowing the difference in height?

If you're blind, no!

You are claiming blind people cannot know that one thing is taller than another without knowing the exact difference?

...how do you know that there is ANY difference?

That's the point!

Maybe she thinks there is a difference while in fact there's none.

Perhaps if I'd taken the time to slow down proofread and spelled giraffe correctly the point would have been more obvious.

The point I was trying to make was you can know whether something is greater than something else without knowing exactly the difference.

A typical of adult giraffe is taller than a typical adult zebra. This is knowable without knowing exactly how much taller.

There was definitively a difference. The cooler was very quiet in the morning and much noisier late at night. After several complaints, it has recently been much quieter at night. I don't know what was done to fix the problem. I'll try to find out and let you know.

Judith P.

...not to mention the weight of such a tank. This would only be possible in a very strong structure, as masonry or concrete.

I don't recall if anyone has mentioned the possibility that the problem could be simply a frayed belt driving the blower.

Use ice as the storage medium, much lighter: Lower cooling costs

True. The phase change stores way more energy, although it might not be an easy conversion from the current system.

Maybe you could produce a soundproof bubble in your room with noise cancelling technology....for just $249.....maybe

https://www.meetnightingale.com/

Just to be clear, the website linked doesn't appear to make any claims about noise cancellation AFAICT. It does make some innocuous claims about providing masking noises.

There are also some claims on the website that would seem to be claims of a medical nature without FDA review/approval concerning treatment of insomnia. I am not a lawyer, so my lay opinion is only that.

Yes I was being a bit facetious quoting the article in "Daily Mail" linked to the picture....it may or may not help in some instances, hence the maybe....

Ahhhh. That makes more sense.

Any other equipment on the roof that may have support problems, and you are the recipient of harmonics?

This sounds like a cooling tower....

They come in all sizes, and in a few different styles....These are used to cool the water down that is used to remove the heat from the apartments....It is precisely engineered to remove a certain amount of heat through evaporation, any reduction of the airflow or rate of water circulation, will effect the ability of the unit to do its job of removing the heat...The maintenance and repair of these systems is restricted to those qualified and authorized to do so...any unauthorized tampering could be met with criminal charges and burden of liability for any damage....If you are a tenant, you complain to the landlord or building owner, if you are the building owner or landlord, or manager, you call a qualified technician to check the system and make any repairs....any and all work must be authorized by the equipment owner or agent....

Thanks for your reply. The picture you sent me is much more sophisticated than the relic we have on our building. I wouldn't dream of touching anything. I have no expertise. I'm just trying to get as much information as I can. Things seem to have calmed down a bit. It was the vibration that was most annoying, and the low frequency pulse. I spoke to an HVAC person sitting in his truck on Lexington Ave. He called it the "chiller". He said that if it's an old one there isn't much you can do to fix it. It is less irritating than it was and I have been complaining to the landlord and person who manages the building. Thanks again for your reply.

Yes I'm afraid there isn't much you can do, the chiller system is very expensive to change, and the building owner is not likely to change it out because of a few complaints...It usually happens when the chiller becomes more expensive to maintain than replace...which can be as much as 30 years or so....It starts breaking down every other week and the repairs get more expensive, and the down time increases, which means everybody starts complaining....then the owner is forced to make the investment....When I used to rent I would always check the A/C unit to see how old is was, if it was a cheap brand, and what kind of shape it was in....When I found a unit with a new A/C system and a higher quality brand, that was my choice....something I learned over the years to make life a little better...it didn't always work haha....

Thanks for your reply. What would be the cost of mounting the existing unit on a rubber base or legs and then using flexible pipe couplings?

Depends on the size of the unit and its pipes as well location but perhaps $100 to $200 installed...???

Way more than that, I bet.

The superintendent of a nearby building told me that putting rubber or springs under the existing unit would be very expensive. Wish the writer from the Netherlands were right, though.

In your 10/14/2018 10:07 AM comment you mention Lexington Avenue.

I'm going to assume that your building is in New York City.

As a resident of NYC for almost 70 years, I can assure you that thanks to bureaucratic red tape, the fix will not be inexpensive.

Yes, to both questions.