Chilled water coils

NRT_Rob

for doing dehumidification in an airstream, I am using chilled water coils.



However, I am not finding any that are "ready to go". they all require custom tin work for condensate removal and, since I need a *lot* of exchanger area, to adapt to 6 to 8" round duct sizes.



does anyone know of:



1. ANY chilled water coils that come housed and ready to go?



and



2. If so, any that would adapt with 6 or 8" round adapters that are commonly available? maybe in a couple of steps?



thanks.

Charlie from wmass

Unico uses chilled water

I think their coils will be far larger than 8 " though. Rittling also has fan coil units. http://www.rittling.com/literature/catalogs/Hydronic%20Fan%20Coils_Jan10_web.pdf

NRT_Rob

Thanks charlie

those might come in handy, but I'm looking for duct-mounted units. The fan part is already taken care of, I just need to wring the moisture out.



Currently I've got an H20 coil unit, but at 24x24 and no housing I have to do a lot of custom work to get it into my ERV ductwork.

TonyS

Rob

try here   http://www.magicaire.com/products/

Techman

ERV?

What size ERV do you have?And what size ducts are on the ERV? The ERV does not exchange enough of its own energy? How long of an on cycle does the ERV have?Just wondering why you need a dehumidifier in line with the ERV?

NRT_Rob

we're doing radiant cooling

with what's called a "DOAS" or "Dedicated Outdoor Air System". Basically, we use the radiant panel to handle most of the cooling load, but we have to handle ALL of the dehumidification in the airstream, and the only fan unit we are using is the ERV... no recirc or conventional AC units or dehumidifiers.



With a properly sized coil and some other design considerations, we can do this in the ERV airstream... the ERV itself just helps us maintain the humidity differential once we have created it.

NRT_Rob

thanks tony

looks like some workable stuff there!

Devan

Air Handler

Rob,



I think your best option is to use an air handler, with duct work sized for the cfm's needed to move air. Tie your water coil into the duct work, with the ERV ducted into that as well.

8" round won't move a whole lot of air, otherwise you may still end up with moisture issues.

NRT_Rob

no way devan!

I'm taking out all the moisture in one shot, and all air in the building is coming from the ERV. Saves a boatload of unnecessary fan energy and ductwork costs. that's the "DOAS" methodology: the whole point is to do only IAQ ventilation CFMs, and do all the sensible load from the panels.



http://doas-radiant.psu.edu/



fun stuff

Devan

I see

I was just figuring on "rules of thumb" duct sizing.

You know - 500-600 sq.ft approx one ton per cooling

350-450 cfm's per cooling ton

ductulator sizing fpm's for 8" round, coming up short for a whole building.



So, what methods did you use for determining cooling loads(latent and sensible), how much OA needed, what will control ERV to run near continously?



Cooled ceilings, definately some neat stuff, a good deal of info and products at this year RPA show, as a matter of fact I had a pretty good conversation with one gentleman from Austria whom I believe is installing ceiling cooling panels at RPA's new place this week in Liverpool, NY as I type.

NRT_Rob

many options

we are going to start with 'off the shelf' stuff first: dehumidistat controlling the coil, thermostat controlling the radiant panel (either floor or ceiling, since we have both, we'll try them both). condensation sensors to shut off the radiant panels.



The fan will run at regular setting for IAQ purposes (currently high speed, it's a new offgassing shop, but we'll turn it down soon), just like any ERV, with boost switches for bath exhausts as well. so it will run at base speed, and boost on dehumidification calls or bath exhausts. I *might* add a duct mounted dehumidistat to allow the coil to run whenever incoming air needs conditioning, without boosting the ERV too. we'll see how things run. Boost speed on the ERV is 200 CFM... it's a residential size unit, pretty standard, and that's more than enough CFMs for most homes for IAQ. Pressure switch on the ERV ensues positive pressure and no infiltration.



I have CO2 sensors as well, so I may just leave the fan on low speed continuous and let the co2 sensing provide baseline speed feedback for the fan as well.



after that though I've got tons and tons of sensors and wiring options (insert maniacal cackling). I'll be running an ENV system and building my own control routines as needed to dial things in or just to learn.



does it show that I am psyched to get to play like this? i'm happier than a pig in... um... nice, warm mud.

Mark Eatherton

First Company...

makes a WHOLE bunch of stand alone FCU's.



http://www.firstco.com/



ME

NRT_Rob

man

seems like there are dozens of options if I want a packaged fan coil.



not much out there for just coils though that are packaged, insulated, and ready to drain. the fan part is already taken care of....



maybe we need to get good at bending up tin. blech.

NRT_Rob

I think it's official

the exact thing I'm looking for does not exist.



and no one makes a 24x24 square x 6 to 12" round adapter...



man, that stinks. knocking tin is no fun.

Devan

First Co.

First Co. have some very good units with water coils.





Rob, you could buy duct without too much tin knocking involved.

eluv8

Coil Company

You might give coil company a call.http://www.coilcompany.com/