Thermofin output

Jay_17

What is the typical heat output per foot from thermofin at say 140 degrees water (copper pipe).
I am mulling over a ceiling radiant system
Jay

Alan(CaliforniaRadiant)Forbes

Engineering

I'm looking at one of their output charts called "Above-Floor Thermofin Output at 8" O. C.", 140° water temperature, R-value of .25, the output is 26 BTU's per square foot.

But:

1) I don't know how that plays out to a linear foot output and

2) I don't think Thermofin is made to accept copper pipe

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Bob Knebel

Cooper tubing is fine in Thermofin

Hi Alan,

Actually 1/2" copper tubing in ThermoFin works great. Our 3/8" version will also accept 3/8" copper. The designs for the plates were based on the outside diameter specifications for PEX (which are very close to copper tube sizes). The fit is snug so you would need a rubber hand mallet or air-driven "palm" hammer with a rubber head to snap the copper in.

One of our first "staple up" jobs with our prototype plates installed many moons ago used 1/2" copper and it worked very well. Talk about performance ...... the ThermoFin heats up instantaneously with copper tubing.

As far as output in a ceiling application, I believe you would get substantially better output behind one layer of sheetrock than the case you referenced which was under 3/4" of plywood (ThermoFins 8" on center). We haven't done the FEA analysis for the ceiling case but I would guess at least 25% better.

Bob Knebel, Radiant Engineering, Inc.

Mike T., Swampeast MO

Thermofin & Copper

Copper fits--it's just not too much fun as it fits perfectly... I used soft copper and "popped" it in with a block of wood and rubber mallet.

Dale told me that it was originally made for a job where they used copper.

With water of about 125°, surface temp of the floor is about 83° in single-digit weather. 3/8" T-fin on 8" centers (3/8" soft copper tube); 3/4" plywood; 1/2" cement board; 3/8" ceramic tile and assocated mortar.

Copper in thermofin can REALLY draw out the heat, so keep that in mind when it comes to length of the loops!

Unknown

WE LOVE THERMOFIN. really, we do.

however, for most ceiling applications, you can dust your sheetrock using just plain old lightweight plates. Wirsbo says 40 BTUs/sq ft at about 115 degree water temperature which is way over what most rooms need.

short answer, I wouldn't pay extra to use thermofin for a ceiling application. Now, if you're doing an underfloor application, that's a whole different story...

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hr

I've done two

copper ThermoFin jobs. I can't say the output is greater, as either pex or copper will get the ceiling to a given temperature, and that balanced against the room temperature gives you the output figure.

Rule of thumb is 2 btu/ square foot per degree difference. So 65° room temperature with 80° ceiling panel temperature woulfd be @ 30 BTU per square foot.

Here is the bonus for ceiling radiant... you can run it hotter than a floor panel since you are not worried about excessive temperature on bare feet! Unless you walk on ceilings

So to my way of thinking you could run, say 90° ceiling panel temperature and end up with more like 50 btu/ sq. ft.

I have 2 weeks of run time on my "interactive" ceiling radiant in my ceiling. I watch, listen and feel the system working. I have run it up to 146° supply. So far no noise what so ever. It feels like a soft sunshine when you walk into this room. I did notice a big difference in the furnishings in the room. The marble toped coffee table is warmer, as is my easy chair. Even with the exact same room stat temperature as the HW BB that previously warmed this area the comfort level has increased noticeably!

I'm not sure copper would actually increase the output but the acceleration would be much improved with a great conductor (copper) in an aluminumn "accelerator plate" ( A great Alan Forbes term

A picture of a copper Tfin job I did 3 or 4 years ago, and my bare naked PAP ThermoFin living room ceiling.

On the copper job I pounded the 20 foot length of copper into the fins on the concrete slab and hung the whole assembly. I used PAP to make the loop ends and allow some movement room. I am actually heating that space with the same temperature going to the slabs in the other bays, @ 110°

hot rod

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Dale Pickard

Sure copper fits

Copper is preferable to plastic for chilled water cooling applications because there is less of a temp range to work with. There is only a 30 deg difference between 40 deg water and 70 deg air and it's hard to go lower than 40 or so. With heating the water temp can be raised to a difference of water temp minus air temp of well above 30 deg more or less as needed.

What's the point? Temp drop of less than 1 deg for type m copper to get across the tube wall. For Pex the temp drop is more on the order of 15 deg. So for cooling it's easy to lose half your driving force. With 40 deg water, the plate may be able to run no colder than 55 deg. A little better with PAP.

It's also important to use copper when using the Tfins as solar absorber plates for the same reason. If the plate has to run hotter than the water temp heat losses from the collector to ambient are higher.

Dale
Dale

Mike T., Swampeast MO

Great Photo Dale!

nm

Tom_35

First Thermofins

We just got our first Thermofins and there is a world of difference between them and the plates we have used in the past. We are prepping the site so that we can access everything without a lot of construction materials to work around.

We're using a nail gun like HR suggested.

Tom A