Wednesday, December 11, 2013

August and September: Tick-Tock, It’s Almost Time

August and September have gone by in a blur! I cannot believe how fast time flies by and as I write this, I feel the oncoming chill of autumn.

Looking back, it always seemed that this project was moving at a snail’s pace … and now it seems surreal that very soon we will have moved in, frolicking in the lounge area and sleeping in the meeting rooms, (ooopps my bad, I mean attending attentively, very serious meetings in meeting rooms), as well as stretching our minds in the thermal labs and demo area and, of course, sitting cheerfully at our desks. 

Well, here’s my early fall update …

We’ve been putting on our best bib and tucker, full tilt!

Here’s our new driveway up to the canopied entrance. The new stucco outer skin is having fresh coats of paint applied. It seemed so much fun and I so wanted to have a go, even if, like the last time I decorated my home, I ended up with more paint on my clothes than on the walls (lol)! 
It’s kind of sad that the old original 1970’s yellowy and brown theme has been replaced with our modern Blue and White ‘Dadanco’ livery, NOT!
The building looks so beautiful compared to all the other buildings in the immediate vicinity, it will surely stand out and I cannot wait to see the final result.
So that’s enough about the facade, what’s happening inside? 
Here are the first images of the ACB10 chilled beam mounted in the bulkhead over the entrance to the Hotel Room mock-up!
With tradesmen working everywhere, traveling down the corridors has to be executed with great care and skill; my years of Ninja training held me in good stead. Don’t worry, I’m sure with Dan inspecting every nook & cranny for compliance in minimizing heat losses, there will be more insulation on the pipework than shown here on the floor! 
Hey! Same ladder! This guy moves fast! Check out the boardroom dropdown ceiling, quite a modern architectural twist. I understand this will be the home to four ACB40 2-way active beams and a metal ceiling, all with a matching perforation.
Talking about twists, check out this serpentine edge to another drop ceiling in our social area and lounge located between the classroom & lab demo areas. 
And now we traipse into the production office. Cassidy’s dwelling place will be right behind that rectangular partition. We wanted to put a pool table there but when we found out it was not big enough to be able to play some of the harder shots, Cassidy got his way!!!  At this point, still looks like a bar to me! My home-away-from-home will be directly across the room to the left of Cassidy, and on that same side of the space. I am so glad that my cubicle will be next to the window… I need my window! It reminds me of endless possibilities of freedom! You have all been in my shoes, so don’t judge!
Beams are everywhere, sitting prettily amidst the foamy insulated ceiling! Look at those snow queens! They cannot wait to be set free to do what they do best-make our life comfortable!
Here we see chilled beams before and after the pipework insulation. So those are the 6 way control valves! Now I understand how you make the 4-pipe distribution work with a 2-pipe coil, as of course, it maximizes the efficiency from the chilled beams at the same time!
Our building has many accessories! Here we have the Taco multipurpose valves that regulate flow and circulate the water in the correct direction at the desired pressure. This type of valve acts as four valves in one: shuts off, checks, balances and meters the flow. How cool is that? It can multitask just as well as any woman can! :)
Another nifty thing, the variable speed drive pumps! Check it out; we got a whole garden of these toys! 
That big red thing? Well, that’s simply the air separator that gets the excess air out of the piping system. There is so much more than meets the eye when it comes to setting up all these systems in a functioning building. Humans are so inventive! I never stop being amazed! 
Here is a whole lot of them! The intricacy of pipework accentuated with shots of red, so cool to look at!
I am no pipe lover, nor do I go crazy over valves, but I can admire the system, the organization and skillful layout and the amount of thought put into setting this all up effectively. 

Is this a spider or a crab? Neither! Here we see the Taco heat exchanger that generates medium temperature water for the chilled beams. Pretty cool, eh?

Yet more Mestek products, this time from our sister subsidiary, Space Pak!
This is one of their Aircell mini air-handlers which will be used to supply low temperature air (48 to 50F) to the Dadanco Inffusers located in the classroom/training room.

 The pipework distribution system was lagged and labeled in September.
Here we see multiple temperature chilled water and hot water supply and return, dual temperature supply and return and low temperature chilled water supply and return.

This is the refrigeration unit serving the hot and cold wall in the hotel room mock-up. Pretty cool fans, wouldn’t you say? 

Having already excavated the hole for the indoor ‘swimming pool’, someone decided that we could use it for the raised floor section of the new thermal lab and so the task of leveling it, before pouring the foundation, began.

The next thing on the list was to put the reinforcement in place. Caution! Don’t get too curious or you may just fall in! Moving forward! Next item on the list, the ‘Rebar’ reinforcement!

Once we are done with the prep work, the cement truck arrives for a morning of fun! So how do you get large quantities of cement several hundred feet to where you need it? Well you could use a couple of large wheelbarrows and brute strength, and a few weeks… or just do it the easy way, lay down a delivery system and pump it there.
Pretty cool and complicated stuff.  Everywhere I look, pipes and more pipes snake their way across the factory floor of the building next door (thanks guys for allowing that!), and then, across our factory floor.  I just hoped we did not spring a leak and eventually all was delivered without incident, amazing!

Gentlemen are having lots of fun filling in the hole. Be quick or you will be cemented in place! :)

Oh, what joy it is to splash around in the wet cement! I was so jealous of the lucky participants, but funny, they never thought it was as much fun as I imagined!

The fruit of all their hard labor, the foundation is filled and left to harden. 

Uh oh!!!What is he doing, filling the space with water? That was what I was hoping for at that moment, “Hey, quick, before anyone notices, let’s turn this back into a pool. I’ve gotten so heated up during the strenuous morning operations that a swim would be just what I need!”

Stay tuned for what happened in October & November and, oh joy, winter once again in Massachusetts!

by Chris Lawrence and Olga Pyshnyak

Thursday, November 7, 2013

Fall into Favor

Fall has been very favorable to Dadanco.

We have had a few great additions to our team, be it our internal team at Dadanco, or our external family of representatives.

Please find below a short bio of our newest team member, Andrew Paice.

Born in Australia, Andrew joined Dadanco Pty in 2005 after graduating from the University of Adelaide with honors and a degree in Mechanical Engineering.  Within 3 years, Andrew had worked his way up to the position of Senior Engineer and over the following 5 years his roles encompassed product design, testing, computational fluid dynamics, technical support and sales.

Looking for a new challenge and wishing to expand his horizons, in 2013 Andrew decided to move to the United States and join Dadanco USA, teaming up again with Vlad & Dan. 

In his spare time he enjoys cricket, Australian Rules Football, motor sport, reading and computer games, both don’t worry, we will soon knock that out of him and turn him into a fan of some real sports such as baseball, football and hunting.

Also, please welcome our newest addition to the family of Dadanco representatives, in this case representing our product line in the State of Georgia -

Thermal Resource Sales, Inc.

5680 Oakbrook Parkway, Suite 105
Norcross, GA 30093
Phone: 470-545-6598
Fax: 470-545-6620

We are very excited about Andrew joining our technical sales team with Thermal Resources Sales strengthening our external sales and wish them all every success.

Thursday, October 17, 2013

DADANCO at the Build Expo, NY!

Please join Dadanco at the Build Expo, NY! Booth # 511, October 22nd and 23rd. Make sure you don't miss our seminar on the 23rd at 9:30am! John Nodson and Dan Harris will be speaking about the local law 87 and presenting the Federal Dirksen case study on PIU replacement. Happy Learning!

Wednesday, August 28, 2013

June and July Update: Gearing Up For The Big Bang.

Summer months are no excuse for dilly-dallying and our construction never stood still! The final big push is coming in the fourth quarter of this year and time is “a-ticking”! From the big details to the smallest, everything is coming together with a cohesiveness that is remarkable. We are starting to see substantial changes that only serve to fuel our team’s enthusiasm! Let’s take a quick peak at what these two months had in store for us…

Immediately, as you walk towards the entrance, you will notice that the canopy has been raised up over the steps. It will serve our visitors well during the rainy weather as they await their limos being brought around by our team of ever-smiling valets, each ninja trained in the ‘Art of Parking Cars and Silent Killing’… providing the comfort of knowing that no one will mess with your ride while you’re busy touring our lovely facilities. 

Right before walking through the door, look right and left and notice that our building’s façade has been revamped by a fresh coat of paint. Mmm…what a beauty! Yeah, ho-hum… you think beige is boring? Hold your horses, don’t judge us yet! More colors (not just another shade of beige) and signs are coming soon to outfit our building! 

Oh, and by the way, we now have the official name for our new home which is named in memory of Prof. Sam Luxton, co-founder of Dadanco, and John Reed, founder of Mestek Inc., ‘The Luxton Reed Center’.

Further announcements, on the change of address and etc., will be made at the appropriate time.

And talking about big details, here you see the roof mounted 8000 Btu/h condensing unit for the cold wall in the hotel mockup room being lowered into place. I was planning on getting the odd 40 winks in there; I just hope the structure guy got his sums right as this baby looks pretty heavy! Perhaps they should put the hotel king sized bed right underneath it, and just to be on the safe side, if I ever need a nap, I’ll check out the bed in the patient room mock-up instead :).  

I hear there will be a mural of a major city in the hotel room, can’t wait to see which city they’ll pick!

Don’t be fooled by the picture in the upper left corner. Remember your mother telling you, “Appearances can be deceiving”. Well, she is right. The picture with all of that activity on the bottom right is really the same space but from a different angle. Simply put, one side of the room is taking a rest…while the other one-isn’t, and boy are the guys working hard finishing off the pipework before the drywall goes up!

Electrical components are taking shape. The bottom left corner depicts the floor outlet for the audio visual equipment, data & power in the boardroom. This will feed the “big-decision-maker” boardroom table that will run across it. I can almost picture our guests along with our guys, with the air of self-importance and tech-savvy, presiding over this table.

Most of the pipework distribution systems are now in place with pipework lopped off, flushed and clean, eagerly awaiting final connection. With so many products from the Mestek subsidiaries going into ‘The Luxton Reed Center’, I just wonder which product these pipes will serve.

Final internal excavation nears completion and the rumor going around for some time was that this would be an indoor Jacuzzi with a swimming pool.  Great idea and what style…

But hey, let’s not get carried away. It’s actually going to be fitted out for the foundation of the new thermal lab chamber; it appears the whole thing will be on a raised floor so that we can control thermal loss through the floor!!! Talk about big details.

I still want it tiled and filled with water but they wouldn’t listen to any of my “nonsense”!

Apparently many of our clients, reps and staff, want to see what this lab can do. Grrrrr, so much for simple creature luxuries, I mean comforts.                                                           

Going back to the title of this blog, this Big Bang that I’m writing about will change the life of DADANCO forever. Not only will we make a short trip up the hill and around the corner from the highway 90 to our new home but we will also start a journey that will inspire momentum, focus and the creative energy of innovation, allowing us to stay at the forefront of our technology. ‘The Luxton Reed Center’ will catapult us into a new era!

Stay tuned for more updates coming your way! 

By Chris Lawrence and Olga Pyshnyak

Friday, July 19, 2013

April  and May Update: No Stopping Us Now

Thankfully the months of April and May brought in a sharp relief to the winter months with fierce intensity of awakened Spring.

Snow –gone, Check! Sunshine-Check!

Moving forward with “The Offices Project”-Check, Check!

Checking in on a daily basis desensitizes you to the progress happening but looking in, infrequently, makes one appreciate the shifts towards completion.

Unfortunately, a picture can’t show the hard effort exerted by the Dadanco team that is overseeing the construction. They are creating a lean and green building that will showcase not just the Dadanco technology but that of our sister subsidiaries, all the while performing the 9 to 5 job of providing application support, product development, production engineering, tendering and continuing to keep Dadanco successful!

This is nothing short of a Herculean achievement, thanks guys!

Let me run by you a few progress photos!

The front entrance beckons, shy of its nakedness but in the next few months it will be outfitted with the most elegant dress. Just watch and see, all you doubters!

Boy, when we get moles in Westfield, we get moles! Anyhow, laying down new drainage from the plant room is almost complete; next stop - sidewalk upgraded to cater for wheelchair access.

Impressive new front doors, not… Don’t worry, the bucket and ashtray will go before we open, promise!
Let’s scope out the interior…

Here is our new entrance from the inside! To the right of it, the new reception area with a fantastically modern look starts to take shape.

Don’t be dissuaded by the lazy wheelbarrow at the door that’s there to carry all the tons of cash we need to pay for the new facilities!  LOL.  It will be gone by the time the clients arrive, the wheel barrow I mean, not the cash!  

Sometime later this year, busy clients with full agendas and hands full of new and exciting chilled beam layouts will be hurrying through our doorway! 

We have a dream! 

This is not war, but the trenches seem to infiltrate the flooring here and there!  Chris said the building would be more European with a moat, but I never imagined it on the inside, so be careful where you step!

At the very top right area is where Dan’s and Vlad’s offices are clustered together. The remaining area will be the sales and applications support, a new cube farm as such, where our engineers’ desks will be arranged skillfully in triangular formations. Top left, the corner of the break out area where we can lay out engineering designs. With all the stud work up throughout the facility, the final layout can be examined and the fight to claim your space starts in earnest…

I’m not sure what the going rate is for the space near an outside window but I’ve already cordoned off my area with some tape that states ‘beware of the leopard!’…

More ductwork goes up in wavy formations, in its own true essence of architectural art.

Look at the symphony of shapes, a feat of geometry and metal! Ok, so it’s got to clear this pipe and follow that structure but a straight duct would just be too boring of a shot to show you, so let’s go with form over function on this one :)

Here rests the lounge/entertaining area. No humans have yet to find relaxation in this space save for this delicate wallflower of a machine. This will be a masterpiece of comfort where clients can chill on comfy sofas. I am afraid it may end up being the favorite room of many of us… If someone is missing, we will know where to look first!

Maybe I should cordon off another area here for me. Those leopards tend to hunt in pairs… so I hear!  Best warn my co-workers to be on the safe side (haha!).   

Just look at that curvy special ceiling profile at the top! How neat is that? I really fancy the undulating waves of this serpentine shape!

The plant room is taking shape with the Hydrotherm KN series condensing boilers (from our sister MESTEK subsidiary, of course) and the Taco pumps are now in situ. 

Can’t wait to see these boilers fire up!

I figured we’ve been inside for far too long.  Let’s go outside to view more additions from the MESTEK family of companies. Just pause to admire the greenery!  Such a contrast to the last blog which featured the Westfield snow… now you see our Westfield greenery budding through :). How fantastic!

Ok,  and back to what you see here, these are the reverse cycle SpacePak chillers (Yes, yet another MESTEK subsiduary. Well, you hardly expected someone else’s brand, right?) installed and ready to go. At about 30 tons capacity,which should be more than enough to deal with all the hot air some of my colleagues produce… well, certanly enough to deal with the  four demonstration labs, the offices, the meeting areas and the new thermal test chamber.

And here, a closer look at this uniform formation trying to catch some shade…

More updates to follow! Until then, enjoy the lovely hot weather we are having…especially if you live in the Northeast as it won’t last much longer!

by Chris Lawrence and Olga Pyshnyak

Wednesday, June 19, 2013

New Videos, Fun and... Educational!

Please visit our training YouTube page to view our newest additions to the program!

Specifically, we are proud to present this video: 

For the metric lovers out there, please visit this link: 

If you have any suggestions or would like to see a video regarding a specific topic, please let us know!

Monday, June 10, 2013

January and February Update: Offices Push Forward.

January and February rolled by as in a blur. Typical of any new year’s beginnings! Lots of plans, commotion, action and looking to the future…

Allow me to update you on what transpired within these months.

Architectural reviews of the interior have been fully set ablaze as the many various layouts and designs were examined, reexamined, considered and reconsidered (multiply by 2 and then take away the 1st number you thought of)… by our hardworking staff.

I am incredibly excited about the outcome as I hear that the interior is going to be amazing! From a fancy lounge and a huge boardroom that Donald Trump would envy to showers in the bathrooms and bike storage for the “green-minded” staff, well, this place is going to be amazing!

Things may be warming up inside but on the outside it’s still “brrrrr” worthy and typical of the mild (some might say almost tropical) Westfield winters, the snow clung to earth as if for dear life! Thankfully, long gone are the days when we had to dig our own footings for the SpacePak condenser units, but don’t tell Vlad, Dan and I made a few bucks from him believing we dug these by hand. 

The outside façade was quite dismal still but a little birdie told me that a lot of work will be done here as well, so watch out world! Our building will be unique for sure!

As it’s too cold to stay outside any longer, let’s investigate in greater detail what was happening inside. For starters, a big ticket item finally arrived from one of our sister subsidiaries, Applied Air, Dallas! OK, no yellow roses, but the yellow fork lift and steel columns at least made this baby feel right at home.

It was no joke unloading the DOAS but the men handled themselves beautifully in the midst of adversity. This monstrosity had nothing on them!

Look at that bare, lonesome concrete plinth! It didn’t have to “cry us a river” (Justin Timberlake, “Cry Me a River”) as it wasn’t vacant for that long. 

And so, shortly after, and as if 

by magic...

The DOAS was sitting prettily on that fine, hard pillow. I was somewhat amazed over what followed in the next few days … A procession of Dadanco and MESTEK engineers coming by to see, touch and swoon over this piece of equipment... 

I’m sure I even heard one of them talking to “her”!!!

Writing up this section on the DOAS, I’ve had to learn what the heck it actually is and a few nifty lessons later, I now appreciate the finer workings of this ‘Dedicated Outdoor Air System’, being a provider of 100% fresh air while exhausting the “used” air, avoiding the recirculation of the stagnant room air over and over. 

And no self-respecting DOAS would dare show its face without having heat recovery and as seen here, our wheel uses the heat of the air leaving to heat the colder fresh air that is being drawn into the building by the DOAS.

Not to be outdone by Applied Air, Hydrotherm, another subsidiary of MESTEK Inc. and sister company of ours, were proud to present us with their boilers. 

Here they are brand spanking new, excited to be here.

Pieces are coming together in harmonious symphony!

Stay tuned for the Spring months’ progress which will be coming shortly!


By Chris Lawrence and Olga Pyshnyak

Thursday, May 30, 2013

Sam Luxton- You Will Be Missed

We announce with great sadness that Professor Emeritus Russell (Sam) Luxton, co-founder of Dadanco, passed away on Friday 24th May, in Adelaide, South Australia.

 As mentor to Vladimir Petrovic, CEO Dadanco, Sam's inspiration and motivation was critical in the early development of the company and the nozzle technology successfully used in buildings throughout the world.

Although we are deeply saddened by the irreparable loss, "His influence lives on within every solution we provide".

Tuesday, May 28, 2013

The VAV versus Active Chilled Beams + DOAS Debate, May 2013 Issue of the ASHRAE Journal

The VAV Reheat Versus Active Chilled Beams & DOAS paper published in the May 2013 issue of the ASHRAE Journal covers an HVAC system design competition for a real office building at UC in Davis, California. The systems under evaluation are Active Chilled Beams with Dedicated Outdoor Air (ACB+DOAS), a Variable Air Volume system with Reheat (VAVR) and a hybrid of VAVR and ACB’s.
Energy and cost modeling was performed for the three systems and the outcomes were published in the article.

Unusual Design Parameters
The reader does not have to venture far into the paper to expose the reasons for the high first and operating costs of the ACB+DOAS system.
It is interesting that the authors have chosen the primary air flow rate of 0.6 CFM/ft2 for this analysis.  Such a high primary airflow rate is not typical for a building of this type.  The high primary airflow rate is the root cause on the outcomes of this paper.  
Typical chilled beam system designs are based on primary air system reduction of 65-70% compared to VAVR.  This is one of the reasons that chilled beams have been proven to save energy by transferring cooling capacity from the air side to the more efficient water side system. 
It is therefore unclear why in this paper the authors have utilized 0.6 CFM/ft2 (ACB+DOAS) that can clearly be designed with approximately 0.2 CFM/ft2, suggesting a misapplication of the ACB design.

Comparison Using Typical ACB Design Parameters
The typical floor plan show of the subject building comprises and open plan office space. Perimeter diffusers were used for the VAVR system and a (12) 8ft long ACB’s to depict the designers Chilled Beam configuration as shown below.   There are some considerable errors in the ACB design layout and sizing.  Had this system been designed with typical ACB design parameters, only (4) 8ft long ACB’s @ 85 CFM are required to meet the load and provide adequate air distribution to the open plan office, as opposed to (12) 8ft long ACB’s.  This results in a total primary airflow rate of 340 CFM (0.2CFM/ft2) for the zone as opposed to 1,330 CFM (0.8 CFM/ft2) that the VAVR system requires at peak load. This 75% reduction in primary air flow rate is more consistent with properly applied well designed ACB system.  To further reduce energy consumption, application of VAV units to the primary air can lower the primary airflow during part load conditions.

The paper claims that part load for this office building is  40% of the peak load, therefore the zone VAVR requirement would be 532 CFM (40% of 1,330 CFM) compared to 340 CFM for a constant volume ACB design, almost 65% more airflow than the ACB primary airflow rate. However, if we consider delivering the primary air to the beams using variable volume, the ACB primary air system can be turned down to the ventilation rate (120 CFM or 20 CFM per person). This again brings primary airflow of the ACB system down to 26% of the part load VAVR design.
Using the occupancy density rate of 275 ft2 per person as shown in the paper, there would be approximately 6 people and a latent load of less than 1,200 BTUH (including infiltration) for the 1,600 ft2 sample zone. This can be accomplished with just 90 CFM of ventilation air with a moisture content of 49.7 gr/lb if the room humidity is allowed to rise to around 54% RH.
So if we now compare apples with apples, we can see that in reality the ACB+DOAS system should have been sized for a maximum primary airflow of 0.22 CFM/ft2 instead of 0.5 CFM/ft2. If the beams are supplied with VAV primary air, the system could turn down to ventilation rate during part load condition which is around 0.08 CFM/ft2.
So why has the ACB+DOAS system been designed with such an unusually large primary air system and why is the design so expensive? These are difficult questions to answer without examining the design documents, but there are some clues in the paper which are discussed below:

The use of 4-pipe chilled beams
For a given primary airflow rate, 4-pipe chilled beams deliver far less cooling and heating capacity than 2-pipe. The result is more chilled beams and/or more primary air is required to satisfy the cooling loads. Modern designs typically use 2-pipe chilled beams and heat the primary air with duct mounted zone coils which significantly reduces pipework costs.

The use of 63°F primary air
Warmer primary air results in more chilled beams and/or higher primary airflow rate for a given cooling load due to the lost cooling contribution from the primary air.
When combined, these factors have a significant impact on first cost and efficiency. The typical floor zone would require around 500 CFM or 0.31 CFM/ft2using 4-pipe beams and 63F primary air, the air could still be turned down with VAV but a significant portion of the ACB benefits are lost using these design parameters.

Low Performance Active Chilled Beams
There is a possibility that the ACB+DOAS design was laid out with low performance European design active chilled beams. Some of the European manufacturers offer compact chilled beams with low density coils that are not suitable for use in some USA buildings. These beams are designed for the European market where sensible loads are generally lower. When used in the USA, this style of beam sometimes requires far more primary air to drive the induction process to achieve the space sensible loads.
So clearly the ACB+DOAS system first costs in the competition design will be higher. The paper claims a 240% premium. This is not typical, most modern chilled beam designs compare favorably with VAV systems although some have a premium of up to 10-15%. Over budget chilled beam designs are usually caused by using 4-pipe beams, oversized primary air, overzealous control design, high chilled beam density or the bidding mechanical contractor’s unfamiliarity with the system. 

Some other issues/omissions were found with the paper:
There is no mention of using energy recovery on the ACB+DOAS.
 “A primary airflow rate of 0.3 cfm/ft 2 is about the lowest possible with an ACB+DOAS system to meet latent loads with the primary air and the sensible loads with the chilled beams.”
Incorrect statement. The latent loads are identical for all 3 systems. The latent loads come from people occupancy and infiltration so they are the same for all systems. If the author is trying to imply that that the humidity must be more tightly controlled in the building with chilled beams then this would only be partly factual, in reality most chilled beam systems are designed to allow the room humidity to drift up to around 55% RH with the chilled water temperature being selected accordingly.
In economizer conditions, the ACB+DOAS design also has higher mechanical cooling loads because it does not have an air economizer while the VAVR design does have an air economizer and thus benefits from economizer free cooling.”
If the VAVR system has an airside economizer can the ACB-DOAS system have one?

ACB systems have a proven track record of safe operation without condensation occurring on the coil.  This can be achieved with minimal controls.  In fact the VAVR system is just as likely if not more likely to have condensation occurring on the 55°F  un-insulated sections of duct or diffuser plenums as they are  exposed to what is likely more humid ceiling plenum air with little air circulation.  The coil in the ACB has an entering chilled water temperature of 57°F and as the water travels through the tubes it continues to pick up heat, increasing the surface temperature of the tubes and fins.  The coil tubes and fins are continually washed with 75°F room air ensuring less chance of condensation occurring on the coil than on un-insulated sections of the primary air system in the VAVR system.

Duct sizing
There should be similar duct sizing velocities for all three options, portraying the ACB only option with less than half the velocity is inaccurately with general duct sizing principles for ACB’s.  The Hybrid system should have been sized with the same duct sizing velocities as the VAVR system to keep a fair comparison.

It’s not VAV vs. ACB
There should not be a battle about which system is the “winner” here in this analysis…. We are firm believers that Chilled Beams do not spell the end of VAV, in fact there are many projects (this building being analyzed being a perfect case) where the two technologies when combined together correctly provide the best energy saving, capital cost and IAQ.   We feel the analysis provided in this paper and the miss application of both the VAVR and ACB system has intentionally skewed the facts of what is both practical and sensible in HVAC design.  We would encourage your feedback and discussion on this topic via your preferred channels.  There is an interesting discussion that is taking place at the following LinkedIn thread:

Holistic HVAC Design, Segundo Services Center, UC Davis, CA.
April 2013 Issue of the ASHRAE Journal

The May 2013 Article comparing ACB+DOAS with VAVR raises even more questions when read alongside an article published in the previous month of the ASHRAE Journal, “Holistic HVAC Design, Segundo Services Center, UC Davis, CA” which covers the benefits of an ACB+DOAS design of a completed building with metered energy results and came second place in the ASHRAE Technology Awards. Some points worth mentioning are below:

· Hybrid VAV and Chilled Beam Design

· 2-Pipe chilled beam used on the perimeter, VAV on the interior

· 100% Outdoor Air (DOAS)

· Primary airflow rate 0.5 CFM ft2 with VAV turndown to ventilation rate

· Heat recovery used on the DOAS

· Demand control ventilation used

· High performance building envelope

· Metered electricity and steam use

· The overall building height was reduced, reducing the construction costs which more than offset the additional first costs of the HVAC system

· Metered electrical energy consumption 38% of 90.1-2004 baseline and significantly lower than the energy model produced for the building

· LEED Gold Building

 By Daniel Harris