Add-on fans for old convectors

SWEI

Anyone have a source for low-profile high efficiency fans that can be retrofitted to 1950's era wall convectors?  I vaguely recall seeing something here awhile back, but perhaps it was on another site.



thanks~

icesailor

What size?

What kind of sizes are you looking for?



If you're looking for this kind of stuff, it's really quality stuff. Especially that floor heater. It is no garbage. I used 4 of the floor blower units, I have never been a fan of them. The coil box is just a box that you stick a toe kick coil and fan in. This one is designed as a floor unit with a super heavy duty floor grate. They come with low temperature thermostats for low temp. systems. There wasn't a single thing I didn't like about them. Including the price. They weren't a give away, but the quality and engineering made it worth every penny.

The owner was a fuss pot artist who almost went with flat panel aluminum baseboard, but chocked on the price and the fact that there wasn't enough wall space to get the required baseboard on the wall. I showed her these and she loved them. Still does.



http://smithsenvironmental.com/

SWEI

Range of sizes

Roughly 3 feet to five feet in length.  They're recessed in the wall -- haven't pulled them apart yet, but I'd guess the fins might 4 inches or so.

icesailor

Sliced & Diced:

No matter how hard you try. you'll be doing some precision surgical carpentry.

With judicial use of molding and other such things, anything is possible. You used to be able to get Airtherms but the last time I went looking for parts, they were non-existent. Its not ever going to look like it was new, but if the client works with you, you can come up with a solution. Those Smith's Environmental units are the cleanest looking ones I have ever seen.

If what you are trying to do is adapt a blower in a standard convector, it's really hard. There's not enough room under the coil for the fan, and you can't make it tight. Over the coil and it is the same problem. Making the fan tight to the coil. If that's what you are trying to do, how do you figure out the output and balance the flow?

SWEI

Yes, it's a retrofit

in an old church.  Convectors along the sidewalls of the sanctuary, which typically only needs heat on Sundays.  Trying to bump up the recovery rate as we design the new boilers and controls.



I'm pretty sure I saw something with a row of ECM DC fans (like computer fans) that would fit in the case.  If not, I know some guys who can probably fabricate them.

icesailor

i guessed:

I guessed that you were trying to do something like that.

The problem with old churches is that they didn't want the attendees to be comfortable. And they built them with those lofty ceilings so as to be closer to their Heavenly Father. Somewhere along the line, someone didn't check with the Physics Professor. There's probably more than enough radiation to heat the building if they turn the heat up as long as they don't try turning it up 1 hour before services. That said, its been my experience with high ceiling places with an over abundance of radiation is to have some form of ventilation device to take the hot air from the ceiling and get it to the floor. And I don't remember the BTU output per human, but a church full of souls looking to the heavens for guidance put out a lot of heat and then need ventilation.

Perhaps an air handler or two, one at either end in the attic or properly situated would be a better answer. You get heat mixing and when you switch to AC in the summer or whenever you need it, the AC is set up perfectly. The other consideration is that the ladies usually come dressed to the 9's and become hot. Hot people sweat. Sweat raises the humidity. A/C does an excellent job of removing excess humidity.

Something to think about. You could spend more on fan coil motors and not be satisfied when ventilation is what you need. Not more heat.

KC_Jones

Is this the thread

You were looking for?  I saw this one a while ago and remembered it.



http://www.heatinghelp.com/forum-thread/137563/Improvised-hydro-fan-coil

SWEI

That might be the one

some good info there in any case, should we decide to fabricate them.  We would control the speed via the DDC system to optimize comfort.



I've reached out to the Jaga folks to see if they will sell components.

SWEI

Old churches and high ceilings

I don't believe the Methodists intended this one to be uncomfortable, but they did build it in a era of stupid cheap natural gas, so the boiler would pretty much chug away at full bore from mid-November through early May.



A few years back they added a row of ceiling fans down the middle of the building to aid in destratifying the air.  We're just trying to find a way speed up the recovery if we can.



I've got them starting on a radiation survey next week so we know what we have to work with.  First pass indicates we may be able to replace the existing two natural draft boilers (Burnham Holiday firing at 480k and a Peerless 211-5) with a single 399k mod/con, or perhaps a pair of 250's.

Gordan

It's working really well

I made baffles from 1/4" plywood to attach to the back of the outlet grill and cut out discharge holes for the fans. The fans are mounted on the back of the baffle. I have four fans on the 60" element and two fans on the 36" element. The fans are 120mm PWM ones, although I'm not using PWM right now; I just have them running open (with the only real control being a snap disc that closes at 90 - I really should have chosen a lower temp) and this has, serendipitously, worked really well, keeping the temperature in this room consistent with the radiant ceilings in my other rooms. I selected the fans for advertised quietness rather than airflow (don't need much of the latter) and I actually have them wired two-by-two in series so that the voltage across each is 6V.



Keep in mind, though, that I triple-stacked the convector elements in the enclosure and piped them in counterflow. I don't imagine that it would work nearly as well with a single-pass element.

SWEI

Thanks, Gordan

good info.



I'll take a look this week and see how much room they have.

icesailor

Old Churches:

In my minority opinion, if you do a careful commercial heat loss on the building, and measure the existing heat output of the emitters, you will be between 20% and 50% over radiated. You need to move the hot air off the ceiling and get it down to the floor with ductwork. I've worked around quite a few old antique churches. If they were heated year around, they were over radiated. Yours might be the exception. But I doubt it.

Have you done a accurate heat loss calculation on it or are you just winging it.

SWEI

Heat loss calc

is waiting on a set of plans.  Should have them Tuesday night.