ceiling-mounted panel radiators?

pat_3

will a panel radiator mounted to a ceiling with 160 temp running through it cause any damage to the sheetrock or tape joints in the surrounding area? just curious,any responses greatly appreciated.

Jamie_5

ceiling-mounted panel radiators?

I am a DIYer attempting to design a heating system for the rowhouse I live in. Although I have not completed the calculations, it looks like radiant floors or ceilings will be unworkable. I have, however, seen ceiling mounted panel radiators offered, and the numbers seem to work for these. Is there anything in particular I should know about using such panels, e.g. , don't run typical radiator temperatures across them, or do they function just like panel radiators mounted on walls? Thanks in adance for any help or advice.

jamie

P.S. Why, when designing radiant floors or ceilings does one take into account the heat that would flow in the wrong direction, i.e., through the roof if working on a ceiling, but that effect is not accounted for when mounting emitters on walls? If it's because conduction is so much more efficient at transporting heat than radiation or convection, would allowing an air space between the ceiling insulation and the heating panel allow one to ignore the heat flux in the wrong direction?

[Deleted User]

thats a real good question..

i'm curious too, cause i was taught that a radiator is 40% radiation and 60% convection..so it would seem to me that for sizing only at best 1/2 of the btu output could be used since there will be little to none, convective heat currents generated by the radiator on the ceiling..the radiant portion is still there of course..thats just my opinion but i'm interested in what others have to say about this..good question..

Mark Eatherton1

Back losses...

to an unrecoverable space are accounted for in the total heat loss requirements (boiler outputs). In the case of an internally mounted panel, back losses are occuring within the conditioned envelope and are therefore not considered an unrecoverable loss.

We've done a couple of ceiling mounted panel radiators on medium temp (less than 160 degrees F) applications and the owners LOVE them.

You just need to make sure that the mounting is stable. Don't simply anchor into sheet rock using winged anchor bolts. Find a framing member and nail it dead on with a good quality lag screw. A falling panel radiator could kill you if it hits you just right...

ME

PS, The output of a ceiling radiator is 100% radiant, No convective action involved.

ME2

[Deleted User]

hey mark,

if the radiator is 100% radiant, and lets say its a 4000 btu rated radiator, doesn't the btu get de-rated due to the loss of convection current potential once its mounted to the ceiling?

Jamie_5

Thank you for the answer to my primary question. I do intend to anchor the radiators to joists or install blocking panels where need be.

Is there a particular reason you went with an average water temperature below 160 F?

Also, I am not sure I understand your answer to my postscript completely. Perhaps my question wasn't clear and maybe I am wrong about accounting for back losses in ceiling panel installations. If one mounts transfer plates below the roof insulation and vapor barrier but above the sheetrock, the transfer plates are mosty inside the thermal envelope of the building; only the sheetrock remains. I guess the question might be rephrased as, why does moving the emitter to the other side of the sheetrock allow you to ignore the flow of heat to the roof? the change in heat loss of the structure from the one side to the other would seem minimal in most cases.

Again, thanks for the advice.

Mark Eatherton1

One would think...

that it would HAVE to affect the net output, but we've never made any adjustments to the output, and we've never had any complaints about under heating. This would be a great question for a Siegenthaler type of guy.

As for the use of 160 degrees, we design our systems as if WE are paying the utility bills. It really has nothing to do with comfort (hot head syndrome). 160 is a good compromise between 140 and 180.

Maybe Siggy will read this and respond. I'm sure I have the answer some place in Richard Watson and Kirby Chapman's book, but it's written in such deep engineering terms as to escape the common man...

ME

pfitter_27

ceiling hungs

Up here in the great white northeast , you will find in many old buildings, a great many cast iron ceiling hung radiators. Most are "B" style radiation, some are pipe coils. Now and then you find other styles. Most were steam, some were gravity hot water, many have been converted to pumped hot water.

Look in the old books, they show the theory was still radiation AND convection despite hanging on the ceiling. Picture if you may, a large quantity of hot air around the radiator spreading out across the ceiling of the room. As it moves away from the hot radiator it begins to cool and fall. "Cool" not turn cold. This sets up a circular motion of air in the room exactly the same as the convection off a low wall mount radiator. I should have stated that you will almost always find the ceiling hung radiators along a wall, not out in the middle of the room.

In the days of large cast iron this was a great space saver. very common in locker rooms, rest rooms, factories, stair wells, mechanical rooms, gymnasiums and auditoriums.

p

Aidan

Radiant Panels

There are radiant panels designed to be installed on ceilings. The Frenger ones have been used in Europe for 40ish years. I've had some experience with a Frenger system installed in about 1976.

There were insulation panels on top of the panels, so the upwards heat losses were mainly due to the air temperature differences.


http://www.sterlingheat.com/html/radiant_heating.htm

Mark Eatherton1

Not that I've experienced...

ME

tombig

Cieling Radiators

This one was resurrected from a dead system in the coach house (wall mounted) to a laundry area cieling. No toggle bolts here guys. 4ft by 11ft, even the dead maen installed it in two pieces. I love the look of old style wall mount and exposed pipe in loft-type, exposed brick applications.