Out with the VAV; In with the Chilled Beam

Wow! I was working on design of these about 14 years ago, the world moves slowly sometimes.

In my 15 years as a Honeywell Field Engineer, I found most VAV systems operating at 30 to 60% efficiency due to poor design, wrong controls, poor programming, bad maintenance and mostly, all of the above. Most systems do not even reset the supply air temp as the average box damper position changes. In a correctly engineered and programmed system, reheats almost never open. A correctly done VAV will always run circles around a chilled beam system when it comes to saving energy and providing comfort. And if you think a VAV system can be incorrectly engineered and programmed......

Absolute agreement with this posting - the idea a system totally reliant on refrigeration can out perform one that can use outside air in part load conditions must be suspect.

The comments on poor commissioning and operation are very valid - but if the designer gives us rubbish in the first place ?

And who says chilled beams are ac anyway - if the Architect provides adequate floor height and the displacement system is correctly sized there should be no need for this "add-on"

Tony J

I have used chilled beams in dealer room in London many years ago. They are much better than VAV systems. A one inch pipe carries the equivalent energy of an 18"x18" duct!

We are currently designing three projects, in California, with chilled beam.

1. UC Santa Cruz Biomed Project – 100,000Sqft lab

2. UC Davis Health and Wellness Center, 77,000Sqft clinic for the students.

3. Columbia College Sonora, new Science building 25,000Sqft lab with a Geothermal Heat Pump.

Gurdaver Singh, PE, C. Eng, LEED^{® AP}

Associate Principal

G U T T M A N N & B L A E V O E T

C o n s u l t i n g E n g i n e e r s

2351 Powell Street 1111 Howe Ave., Suite 155

San Francisco, CA 94133 Sacramento, CA 95825

P (415) 625-0730 x 122 P (916) 921-1956

F (415) 625-0735 F (916) 921-1921

C (209) 241-6583

E gsingh@gb-eng.com

W ^{www.gb-eng.com}

Chilled beam is an interesting alternative and I'm seeing a lot more discussion about it as a viable alternative. Another research worthy alternative I've found is VAV diffusers. They are a little closer to the comfort zone of specifying engineers.

Thanks. There's also a nice concise and recent discussion on chilled beams here on the EnergyDesignResources website.