Staple Up.... to plate or?

Steve_11

On the topic of staple ups and plates, has anyone ever tried to use that foiled based bubble wrap in lieu of extruded aluminum plates? My guess is that with the extra insulation value of this blanket it would work as well if not better than plates. More radiant heat would be reflected upwards. Simply blanket the tubing directly. An added benefit may be that it is quieter on thermal expansion too. I think it comes in 12" widths and might be an economical alternative.
Your inputs are greatly appreciated.
Steve

Calgary

ps remove the _butspammenot from email address to reply direct

Chris Maderia

Wouldn't work

No way would this work. The wrap has a R-Value and would require very high water temps beyond those recommended for joist heating. I guarantee it wouldn't work. You would have to drive through a total R-value to include the floor equal to or maybe more than the insulation below the radiant. I wouldn't even attempt this.

Duncan_2

Conduction

Conduction is the key.

Think of a warm, not hot, frying pan. Holding your hand to the side of the pan, you feel radiant heat. Holding your hand above the pan, you feel convection and radiant. Pressing your hand ON the pan, you feel conduction.

Plates increase the area of conductive heat transfer between the system water and the floor.

The heavier extruded plate has a large cross sectional area to act as a large heat conduit for conductive heat transfer, MUCH more than thin flashing. Hold a piece of flashing in a flame and a piece of heavier, say 1/8" aluminum over a flame. Which carries more heat to your fingers?

Q = U x A x dT is the conductive heat transfer equation, where A could be the cross sectional area of the plate, or the area of plate to tube contact, or plate to floor contact.

Hope I'm not belaboring the obvious, just trying to help explain.

Wayco Wayne

Also

for the foil to get full R-value there must be an air space in front of it or the infra red of the heat will go right through the foil and not reflect back to the floor. The bubble foil does not have a very high R-value (conductive resistance)in and of itself but when used properly to take advantage of it's reflectivity it has what the manufacturers call a value equivalent to an R value. They sell it around here to wrap ducts for A/C. If you read the instructions carefully (not the manly thing to do I know) it's insulation value increases significantly if you wrap spacers around the duct so theres an air space between the foil/bubble wrap and the duct. WW

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