Radiant seating pads?
Last Post 23 Jan 2015 10:03 AM by sailawayrb. 12 Replies.
Printer Friendly
Sort:
PrevPrev NextNext
You are not authorized to post a reply.
Author Messages
ICFHybridUser is Offline
Veteran Member
Veteran Member
Send Private Message
Posts:3039

--
19 Jan 2015 08:16 PM
I have a problem with a bumpout kitchen nook that's all glass.  When it is very cold out, there just isn't enough radiant heat getting to people seated there.  It's not a problem when the kitchen is in operation because of the various heat sources there, but when nothing else is going and the temperature dips down to the teens, you can feel the chill from the windows.  Does anyone know of any radiant heat pads that I can put under the upholstery there?  The seating area is wood cabinetry and there is wiring for outlets in them.
sailawayrbUser is Offline
Veteran Member
Veteran Member
Send Private Message
Posts:2270
Avatar

--
19 Jan 2015 09:48 PM
Sounds like this area should have been a separate zone with closer PEX spacing.

How about a radiant panel?
Borst Engineering & Construction LLC - Competence, Integrity and Professionalism are integral to all that we do!
ICFHybridUser is Offline
Veteran Member
Veteran Member
Send Private Message
Posts:3039

--
20 Jan 2015 08:09 AM
Yeah, well, it's like 4' X 6', with no real separation from anything else and I didn't want to make it a zone because I knew it might have this problem and I didn't want to create a control element that would force the heat plant to run all the time.

There are rigid radiant panels?
BadgerBoilerMNUser is Offline
Veteran Member
Veteran Member
Send Private Message
Posts:2010

--
20 Jan 2015 08:41 AM

What is the load for this area?

I use panel radiators in kitchen nooks where possible and always radiate the bench, if there is one. I am not above using some convention along the window via a perforated or slotted bench top and bottom.

For areas with a lot of glass e.g. sun room we often use radiant ceilings to supplement and for micro-zones use a loop, indirectly, off the water heater.

Closer tube spacing is rarely effective in overcoming short output, but without good software it is really just guesswork.
MA<br>www.badgerboilerservice.com
sailawayrbUser is Offline
Veteran Member
Veteran Member
Send Private Message
Posts:2270
Avatar

--
20 Jan 2015 01:54 PM
Closer spacing provides significantly increased upward heat flux for the same circuit supply temp for efficient concrete hydronic emitters. This doesn’t work nearly as well for inefficient plate emitters especially if covered with insulation (e.g., hardwood or carpets), but not much works well with these emitters. So if that is your experience, than that's what you know...

Running the initial hottest section of PEX closest to the perimeter will also help offset the higher perimeter heat loss. Doing both these things will generate a higher heat gain in this area than the other average heat load areas with the same circuit supply temp.

Then having a separate zone for this higher than average heat load area would allow maintaining the comfort level in this area. Yes ICF, this would likely require the heat source to run more and you would also have to run the numbers to ensure this wouldn’t also cause the heat source to short cycle too. Given that this area likely sees relatively limited use, an electrical heat source solution that could be used only when this area is actually being used may be the best option.
Borst Engineering & Construction LLC - Competence, Integrity and Professionalism are integral to all that we do!
FBBPUser is Offline
Veteran Member
Veteran Member
Send Private Message
Posts:1215

--
20 Jan 2015 07:32 PM
Consider changing the top of the seats to ceramics and installing electric radiant under them??
ICFHybridUser is Offline
Veteran Member
Veteran Member
Send Private Message
Posts:3039

--
20 Jan 2015 08:05 PM
Running the initial hottest section of PEX closest to the perimeter will also help offset the higher perimeter heat loss
That's what we should have done. As it is, the area is on the end of a circuit. Although, I'm not sure how much it would have helped. The problem is that the entire nook is seating, so there are several layers of cabinetry for the seating, not to mention drawers underneath, so it is well insulated from below.

I'm sort of leaning towards installing some electric radiant panels in the seats and the back and making the upholstery quilted, so it will have thinner areas the heat can get through.
BadgerBoilerMNUser is Offline
Veteran Member
Veteran Member
Send Private Message
Posts:2010

--
21 Jan 2015 07:52 AM
The problem is comfort. You can use tile but it will feel cold unless you are in design conditions and the tile panel is energized.

You could have tightened up the tube spacing but you wouldn't have noticed the difference. Like suspending tube in a 4" slab; you need instruments to record the difference.

I actually model variable tube spacing on dedicated radiant floor CAD software.

Electric radiant panels cost more to install and typically triple the operating cost.


Tube the bench and call me in the morning.
MA<br>www.badgerboilerservice.com
Blueridgecompany.comUser is Offline
Advanced Member
Advanced Member
Send Private Message
Posts:656

--
21 Jan 2015 11:52 AM
Not that this will help but we once installed a radiator system (flat panels), and in the nook under bay window benches we ran slant fin in the base toe kicks to add heat to the area with out any visable radiators, It was custom, removed the slant fin metal jacket and just uset the copper tube and finns, this sat deeper in the to kick then made a custome wood grill /slats to let heat out and hide the emiter.
You have likley thought about this but I will say it, what about adding a sandwich type system to the top of the bench, run it off the end of the floor loop.
Dan
Dan <br>BlueRidgeCompany.com
sailawayrbUser is Offline
Veteran Member
Veteran Member
Send Private Message
Posts:2270
Avatar

--
21 Jan 2015 02:00 PM
Let's assume and enter into any good HR software: 500 SF concrete slab HR heated floor, 5000 BTU/H room total heat loss (400 BTU/H downward floor heat loss), and 0.5” diameter PEX. Required upward heat gain is 4600 BTU/H and floor surface temp will need to be 75.8F in order to provide it.

12” PEX spacing, 89.8F circuit supply temp and 0.34 GPM results in 4600 BTU/H actual heat gain.

6” PEX spacing, 89.8F circuit supply temp and 0.34 GPM results in 7551 BTU/H actual heat gain.

7551 BTU/H is 64% more room heat gain than 4600 BTU/H at the exact same 89.8F circuit supply temp and 0.34 GPM flow rate.

Let's assume and enter into any good HR software: 500 SF above-floor plate system HR heated floor (with R1.0 floor finish), 5000 BTU/H room total heat loss (400 BTU/H downward floor heat loss), and 0.5” diameter PEX. Required upward heat gain is still 4600 BTU/H and floor surface temp will still need to be 75.8F in order to provide it.

12” PEX spacing, 99.5F circuit supply temp and 0.34 GPM results in 4600 BTU/H actual heat gain.

6” PEX spacing, 99.5F circuit supply temp and 0.34 GPM results in 5966 BTU/H actual heat gain.

5966 BTU/H is 29% more room heat gain than 4600 BTU/H at the exact same 99.5F circuit supply temp and 0.34 GPM flow rate. 29% is significantly less than 64%. A 99.5F circuit supply temp is 10% inefficiently higher than 89.8F. There is no floor surface temp difference between the concrete slab HR heated floor and the above-floor plate system HR heated floor so "comfort" is identical.

Moral of the story… People who design HR floor heating systems really need to obtain a copy of John Siegenthaler’s Modern Hydronic Heating and actually study and master it before designing these systems. People who design HR floor heating systems really need to actually know how to use good HR design software when designing these systems and not just blow smoke out their butt...

Borst Hydronic Radiant Floor Heating Design Software
Borst Engineering & Construction LLC - Competence, Integrity and Professionalism are integral to all that we do!
BadgerBoilerMNUser is Offline
Veteran Member
Veteran Member
Send Private Message
Posts:2010

--
23 Jan 2015 07:30 AM
"People who design HR floor heating systems really need to actually know how to use good HR design software when designing these systems and not just blow smoke out their butt..." Finally, a subject to which you may accurately claim mastery!
MA<br>www.badgerboilerservice.com
StuieUser is Offline
New Member
New Member
Send Private Message
Posts:60
Avatar

--
23 Jan 2015 08:19 AM
.....................
sailawayrbUser is Offline
Veteran Member
Veteran Member
Send Private Message
Posts:2270
Avatar

--
23 Jan 2015 10:03 AM
I love the way you turn into a two year old when you get called out on the ignorance you post, LOL!
Borst Engineering & Construction LLC - Competence, Integrity and Professionalism are integral to all that we do!
You are not authorized to post a reply.

Active Forums 4.1
Membership Membership: Latest New User Latest: janvin New Today New Today: 0 New Yesterday New Yesterday: 0 User Count Overall: 34705
People Online People Online: Visitors Visitors: 92 Members Members: 1 Total Total: 93
Copyright 2011 by BuildCentral, Inc.   Terms Of Use  Privacy Statement