High Velocity HVAC

[MrWaj]

Has anyone had any experience with High Velocity HVAC systems? They run 2' or 2.5" round flex duct for the supply. Supposedly very quiet. I would think that you would design for baffled silencers.

https://www.unicosystem.com/#close

[Soundman2020]

"high velocity" and "very quiet" do not go together! Interesting that they make such claims, yet provide no actual test data or numbers, on either the velocity or the sound spectrum!

I would think that you would design for baffled silencers.

Yes, you would need substantial silencer boxes on such a system. It doesn't say how noisy that system is, or what the air velocity is, but the usual reference point for studios is air velocity at the register less than 300 FPM, and overall NC less than 20. with 15 being preferable. They don't mention ANY numbers that I could see on the web site, so there's no telling what they mean.

Also, it seems that this system uses several small diameter tubes to supply air to the room, so you'd need one silencer on each tube... that's a lot of silencers! Plus a similar number of return "tubes" going back to the AHU... I'm not sure if I'd want to build a couple of dozen silencers for my studio....


- Stuart -

[MrWaj]

They are claiming 20 without any other treatment. We can't use a conventional HVAC due to duck work being to big and the only other option would be a mini split system but then we would need to have a separate fresh air supply.


https://www.unicosystem.com/#ws_youtube_2236

[Soundman2020]

They are claiming 20 without any other treatment.

20 what? Measured how?


- Stuart -

[MrWaj]

If you page down on their home page they show a decibel meter reading while their system is running as compared to others (for what it's worth).

[chrispire]

If you page down on their home page they show a decibel meter reading while their system is running as compared to others (for what it's worth).

Looks like they are using an iPad to measure noise levels (or perhaps that’s just a viritual representation of what they really used). I would be amazed if an iPad was capable of accurately measuring noise levels down to 20db. Healthy skepticism officially engaged.

[Soundman2020]

Looks like they are using an iPad to measure noise levels (or perhaps that’s just a viritual representation of what they really used). I would be amazed if an iPad was capable of accurately measuring noise levels down to 20db. Healthy skepticism officially engaged.

Not many professional meters can accurately measure levels at 20 dB. Most commercially available meters don't even have scales below 30 dB or so. Plus, you'd need an anechoic chamber to measure levels that low, yet that photo does not look like an anechoic chamber!

There's a saying in Spanish that I love: "El papel aguante mucho", which literally translates as "Paper can handle a lot", but the implication is that writing things down on paper doesn't make them true: Paper can "handle" whatever you feel like writing on it, regardless of how true it might or might not be....


- Stuart -