A \"super\" heat transfer plate (hr)

Kal Row

me too, i only wish this stuff was like bread'n'butter...

it's hard to get a good continuous cash flow out of the hi end stuff - the "gas co" contractors, who are poping in natural draft cast iron right and left, or worse, scorched air, are laughing at us paupers ;(

Unknown

space shuttle and airplanes

Use hi temp glue all the time. We actually were looking into a peel and stick for the tfin.

what does the themral picture look like after 6 or 7 hours of running??

will the graphite crack and break down in time like bakalite?

looks cool!!!

wheels

John Schober

graphite heat spreader technology

All - the natural graphite technology we are talking about here is for real. See www.egraf.com (my company). It is basically the same patented material that is used in every Samsung plasma display TV (to cool the back of the panel and prevent burn-in), Sony Vaio and Panasonic Toughbook notebook computers (to cool the CPU without fans), etc.
We are working with industry experts like Hot Rod to get feedback before we roll this out to the broader radiant heating industry. So far, the feedback is good and validates our internal testing.
The graphite material is up to 500 W/mK (2.5x aluminum) thermal conductivity, plus it is anisotropic (lower through-thickness conductivity than in-plane), so it makes a great heat spreader (spreads laterally preferentially than going through). It meets brutal consumer electronic pricing requirements and is RoHS compliant (i.e. non-hazardous). Pyrolytic and diamond are other forms of graphite that are extremely expensive and should not be confused with natural graphite.

ALH_4

Graphite

Could a plastic heat transfer plate work? Would it hold the tube tightly for 50 years? The issue of how to fasten a non-metallic plate to a plastic tube is a tough one to solve. It is also an important issue, because it appears to be the bottleneck in the heat transfer chain.

I know nothing about this technology. Is there a ratio of lateral heat transfer to the "through" heat transfer? Can this ratio be controlled during manufacture? How thick might this graphite layer be to transfer heat 8" either side of the tube? Where does the graphite come from? Can the graphite be applied in an extrusion process?

This sounds like a worthwhile concept to me, based on my very limited knowledge.

heatboy

Labor?

Sounds like even more time in a joist bay, to me. I am assuming this is a paste that gets brushed onto the plate?

Does it makes sense to put it on the thin stamped plates that don't have very good contact with the tube and were always just a marginal improvment over suspended tube?

Would it help extruded plate performance enough to offset the added labor in prepping the plates before installation?

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Kevin_in_Denver_2

EdyLogicMstr.

Responses to questions

I appreciate the questions. Here are a few responses:

The issue of how to fasten a non-metallic plate to a plastic tube is a tough one to solve. – The material is flexible / conformable, and we can laminate it with adhesive, so we anticipate that contact to the tube will be favorable

Would it hold the tube tightly for 50 years? We do not anticipate that durability/longevity will be a problem, but we have to test.

Is there a ratio of lateral heat transfer to the "through" heat transfer? – Yes

Can this ratio be controlled during manufacture? - Yes, and it can be varied

How thick might this graphite layer be to transfer heat 8" either side of the tube? We are evaluating optimal thicknesses and thermal conductivities

Where does the graphite come from? Natural graphite is a mined material, found around the globe. We are unique in our ability to process it in the required form.

Sounds like even more time in a joist bay, to me. I am assuming this is a paste that gets brushed onto the plate? It is a solid sheet of flexible graphite

Would it help extruded plate performance enough to offset the added labor in prepping the plates before installation? We are optimistic that our solution will offer a labor savings.

ALH_4

Graphite

John, thank you for the response! Could these graphite "plates" be extruded? If so, I imagine something similar to an 8" wide plastic tube clamp (minus the ribs of course) extruded in short sections.

hot_rod

Andrew may reconize this piece

from his days at Radiant Engineering... This is one idea I had for the loop ends as a means to get ideal tube wall to graphite connection. The aluminum sticks VERY well to graphite with 3M VHB (very high bond) tape. This tape is used in aircraft construction.

I'm still looking for the best and less labor intensive way to get the SpreaderShield held tightly to the subfloor. When we get that link I have no doubt we have a better radiant conductor with a less labor and cost of goods solution.

hot rod