heat tranfer plates

Rob_25

I appreciate your comments, especially coming from experts in the field.

I made about 450 plates to use in a new 800 sq ft addition. Most of them were blanked out at about 6 7/8" wide (7 equal pieces from 48" wide sheet). After bending they're about 6" wide. I put 2 rows in each joist bay (16" C-C) so there's about 1 3/4" between the rows of plate. End to end I left about 3" between plates.

I'm not sure about the time. I guess as I think through the steps (shear blanks, bend u-shape, press radius, straighten, punch holes) I probably had 20-24 hours in making them, not including the dies.

I used a barrier pex, not pap. Occasionally I'll hear some expansion noise, but I think its where I looped from one joist to the next. I don't think I get any from the plates. My control is a Tekmar 422 with injection mixing. Its not quite constant circulation, but its typically circulating most of the time. I've learned from you guys that that helps with noise.

Overall I'm very happy with the setup. We love the warm floor and the consistent feel of comfort. I think I'll eventually do the same to other rooms in the house. Although I don't mind setting the thermostat higher in the rest of the house since we're now burning wood in a gasification boiler.

Thanks again, Rob.

[Deleted User]

I found that heat transfer plates are very costly. I would like to make my own. Should i use sheet metal or aluminin.Has anyone made their own heat transfer plates? open to suggestion

hot_rod

Sure

you could build your own. I doubt you will get the fit or transfer-ability of the nice extruded style, however.

The tube fit is critical, as is the metal thickness to prevent noise issues and provide the best heat transfer.

hot rod

hot_rod

Brad White

Define

"very costly" (without naming a number of course

There are rolled aluminum plates, thin enough to staple, not to mention the extruded aluminum plates which I find more effective. There are so many variables. I have heard of using discarded lithograph offset plates from your local newspaper. One local paper used to practically give them away.

The big questions though are, "What is your time worth?" "What is the long-term cost of unproven, home-made heat transfer plates".

Given that one is only going to install a system once, I would not skimp on materials, personally.

My $0.02

[Deleted User]

brad ,i have a bead roller machine.the transfer plates are aluminun. i was thinking of using sheet metal, is sheet metal be a better conductor of heat?

jp_2

Nope!

sheet metal is not better than Al.

if you could get the same contact as the extruded Al plates you would be close, maybe 16th inch sheet metal?

tin foil would work, but with the high cost of energy, the big question is "How well ?" the better iT works, the less money is costs you year after year to heat, thats the big question!!!!

PS no Plates work too!

scrook_2

aluminum...

Type 1100 or 3003 aluminum sheet is probably the material of choice, 3003-0 will be a bit softer/weaker then 3003-H14 though the -H14 is probably more readily available. 1100-0 or 1100-H14 are probably equally available, again -0 is a bit softer/weaker than -H14. 1100 is basicly pure aluminum (99%), 3003 has a bit of manganese added to make it a little stronger.

Brad White

Hard to beat

that kind of answer!

ALH_4

Extruded Plates

I believe most extruded plates are 6063-T5.

Brian_18

Don't Repeat this Mistake

Mike:
I'm a DIY'er as you probably are. I installed under floor radiant in my new addition 2 years ago. Did LOTS of research, asked LOTS of questions, performed countless calculations, and am extremely happy with the results. I used extruded plates. A family friend was visiting, and really liked how the room (and floor) was so comfortable. He then wanted to retrofit radiant in his family room which always felt chilly. I agreed to help, and long story short.....he balked at buying extruded plates, opting to form his own from aluminum flashing. I shook my head figured what the outcome would be. Last heating season, he could never get the room warm, without using supplemental heat from the forced air furnace. Over the summer, he pulled down all of his home made "plates", and installed extruded plates. Bottom line is, do your homework, perform ALL calculations and trust what they tell you. Otherwise, you could end up doing the job twice.

ALH_4

Heat Load

It is very important to evaluate the heat load to determine whether the additional output of extruded plates is necessary. Even if it is not, extruded plates perform at lower temperatures than sheet metal "omega plates" and will run a mod/con boiler at a lower, more efficient temperature.

Rob_25

Alum Plates

I used .060 Aluminum for the plates I fabricated. I think most of it was T3003-H14, although there may have been some 5052. I guess I have an advantage over most in that I work in a fabrication/machine shop and have access to a lot of nice equipment. I was able to machine top and bottom dies (about 2 ft long) and form the plates in a press brake.

One well established local heating contractor told me alum plates weren't worth anything and said they fasten the tubing to the side of the floor joist. Needless to say, I'm glad I used plates and they work quite well. I'm sure they're not as good as extruded plates, but they're probably a lot better than the thin plates that you can buy.

I don't think I could make them cheaply enough to sell them, but I only had to pay for the material at cost.

fatty_2

nice work on those plates

[Deleted User]

GREAT JOB ON THE PLATES!THE SPACING BETWEEN PLATES 3" OR 6"?HOW MANY PLATES DID YOU MAKE UP? HOW LONG DID IT TAKE YOU?

Andrew Hagen_2

Plates

That's really nice! Those are the best plates I have seen that weren't extruded. I wouldn't discount these as a viable product without some futher investigation. Extrusion is expensive, although so is sheet aluminum. Do you have any issues with pex expansion noise? Did you use pex aluminum pex? How was the installation?

Unknown

That is a really nice looking plate, and I would second everything andrew said. this is way beyond the typical DIY sheet metal plate. The only thing additional an extruded would probably offer is slightly easier install with the "under plate" tubing groove allowing for plates to go up and tubing to snap in, you're pretty darn close to the same thickness as the extruded plates and you've got pretty close to the same amount of tubing contact (and a nice fit, I might add).

very nice job!

dana_3

plates

i always thought with two pipe plates that you secured the plates in the middle, to allow the expansion of the plate to go outward to the ends. as with yours ,you've secured on both sides of the tubing , causing the plate not ot expand properly. any input would be appreciated

Rob_25

I think I have read some comments about fastening just one side the plate. I felt like that didn't give good contact with the subfloor so I fastened both sides. Also, I wouldn't expect much (if any) expansion with the plate. The pex would expand axially, along the length, so I don't think fastening both sides is a problem. Having the plate clamp the tube tight is where I could see a problem.

Let me follow that up by repeating that this is not my field and there are many here more qualified to answer.

kevin coppinger_4

that is ...

only if you use sheet metal...those are much thicker plates and won't have the expansion issues. kpc

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Unknown

as others noted, what you've seen there is for lightweight plates, not heavy gauge plates like are being used here.

That said, the idea of completely defeating the idea of installing an aluminum plate by not fully and firmly affixing it to the subfloor is a bad one. In joist systems, you should staple the living heck out of lightweight plates, or you are losing very significant amounts of effectiveness with most plates. you can gauge for yourself how much isn't touching though.. that's the big thing, you want a lot of it touching firmly to the subfloor.

I normally recommend fighting expansion another way; using expansion loops, watching your water temps, using reset, even using PAP tubing.. but don't cripple your plates.

Extrudeds are a lot better anyway but still.

for *above floor* sandwich applications or in ceiling heating, I'll recommend stapling one side of a light plate to allow it to accept the tubing after the fact.. it doesn't affect the final contact of plate to finish floor in that case. but in joists, staple staple staple.

hot_rod

the weak links

as your picture shows is the plate to tube connection. ideally a tight press fit around 180 degrees of the tube. this is where the heavy extruded plates excel as they can be built with a tight press fit but also hold that fit after the tube is pounded in.

Noise issues can arise when the tube "moves" in a loose fitting plate and also as the metal deforms when heated. Known as "oil canning" as it sounds like those old oil cans you dent to operate

The next important connection is the plate to subfloor. The more rigid and heavier the plate the better that connection becomes. Again thin plates can be noisy if they move or crinkle when heated.

I'd say for a stamped or formed plate you did a nice fab job and they should perform well. if you find the tube connection to the plate is loose some silicone would help the "connection" and prevent noise caused by tube movement in the groove.

I'd use pAP or FostaPex to limit the tube expansion issues.

FostaPex might be the best tube as the od is a bit larger for a good friction fit.

hot rod

[Deleted User]

can a different metal be used?