Radiant ceiling/wall in HE home

SENWiEco

Good evening group.  New to HeatingHelp.com which was recommended by Richard McGrath. Thanks Richard



I also posted on a couple of LinkedIN groups and have received a mountain of data from Robert Bean that I will have to go through in the upcoming days.  But I would still like to hear from people that live in or design these type of systems and here what are the pros and cons in your opinions on a wall or ceiling panel design.



I am designing a single family dwelling in North Vancouver BC that is

planned as a high performance - low energy home. I plan to use hydronic

heating in the home (don't really want to get into a debate about forced

air vs. hydronic please).







As this home will be very well insulated (R40 walls and R60 ceilings

effective) and air tight, and will be able to capture a LOT of solar

heat gain, I was planning on using hydronic transfer plates mounted in

the ceilings. This would reduce the mass of the system allowing fast

termination of heat output reducing chances of set temp overshoot. This

also allows for a higher panel temp and therefore smaller panel size and

is not effected by changes of flooring down the road.







My review of John Siegenthaler's Modern Hydronic Heating book and other

sources indicate that all of the surfaces that 'see' the ceiling

(including exposed floors) will be slightly above ambient air temp and

that the floor is these systems are typically 3-4 F warmer than they

would be in a room heated by convection. I was planning a panel temp of

110F or below but will tweak once I know the room loads (have not got

load model yet). It is recommended to keep around 100F if only an 8ft

ceiling but I have 9ft for first floor. I also know you should never go

above 120F or you will degrade the drywall. (I also plan solar

collection down the road so need to keep a low operational temp)







For second floor I have 8.5ft ceilings that vault to to around 9.5ft but

am probably going to do a mixture of wall panels and floor panels

(bathrooms only which are usually always tile and so a very effective

radiator) on that floor to reduce heat loss to the outdoors that would

otherwise occur through the roof assembly. No sense designing a R60 roof

and cutting that in half by adding a heat source into the assembly.







But the real benefit and reason I am looking at this is the lower

mass/faster reaction and the fact that it becomes flooring independent -

a huge drawback with traditional floor panels. It also allows for

longer span floor joists due to the reduced load of not having gypsum

cement embedment layer. Also means I am not heating my slab in the

basement which contributes to huge slab edge losses.







Most of my knowledge of these type of systems has come from John

Siegenthaler's Modern Hydronic Heating book (excellent by the way). I do

not have any direct experience. I would like advise as to the typical

performance of these systems (looks good on paper but??) Design pitfalls

I should look for and avoid. And products and installations that are

today's best practices.







Any help and guidance is very much appreciated

Zman

Very good start

Siggy is excellent, you are off to a great start.

Your low mass approach is dead on.

I would design the panels so that they will work at the lowest water temps possible. All high efficiency and alternative heat sources prefer lower temps. Condensing boilers, heat pumps, solar panels ect. all thrive at lower temps. I would not go any higher than 120 degree water temp on the design day.

I have used Uponer joist track in walls with great success. They provide some great resources like the CDAM design manual.

Many super smart folks on here, welcome.

Carl

hot_rod

I like that concept also

I did a ceiling retrofit to my home a few years back. So far, to my wifes dismay it is still exposed ThermoFin and tube



It ramps up very quickly, runs on reset but rarely above 120F. It's clean, quiet, and not encumbered by room furnishings.



You can build it into the ceiling sheetrock, or use some manufactured ceiling products.



This company, Zender, had an amazing booth at the German ISH show this year. They build some really unique panels. i believe some of the product is being built in the western New York area, and easy to source.



You can buy all sorts of cool radiators also, here are a few copper and concrete radiators I build.





http://www.rittling.com/home/low-temperature-heating-and-high-temperature-cooling-systems/

Mark Eatherton

Great idea but….

and there's a but in every crowd, ain't there :-)



I'd first recommend you start with a heating AND cooling load calculation. This will then determine the load. You can then reverse engineer it and determine what maximum water temperatures you think you'll have available from your alternative energy sources, which will then dictate square footage of emitting surfaces necessary to counter the load.



I know you don't want to talk about forced air,but you MUST ventilate this dwelling, or you will create a whole other host of indoor air quality problems. It doesn't need to be HUGE, but you will have to keep it fresh and dry.



I'd also recommend you consider radiant ceilings over walls, because you will have SOME need for cooling, albeit a small load, you MIGHT be able to provide the cooling through a reverse indirect connected to your incoming water supply, and that then connected to your hydronic system.



I have radiant ceilings in my home in the mountains, and I LOVE LOVE LOVE it. The floors are never real cold, in fact quite comfortable at design conditions.



Start with a load calculation and you can move forward from there. The first Passiv Haus I had an opportunity to work on had a load of 5 btus/ per square foot…. (wait for it…) per YEAR. I told the builder we could heat it with bodies, and he agreed, but said he had no control over their traveling away from the house, and were unreliable, hence the need for a comfort conditioning system.



He ended up going with a European (Polish) ERV with toaster elements in it to augment heating needs. His house was also covered with PV panels, so that decision made sense. His goal was to build a NZP (Net Zero project) home. Haven't talked to him since it was built, so haven't had a chance to find out performance.



ME

SWEI

Load calculation

will likely reveal that you need lower temps than you think.  We are mid-way through a house with R-30 walls and R-50 roof (10ºF design temp here) which will need 91ºF water at design conditions.



I would suggest two zones -- one for the rooms with south facing glass and one for those without.  This is the best way to deal with high winter solar gains.  It's best to use a proportional zone valve for this, paired with a thermostat that has an appropriate output (Honeywell and Viconics make them.)  The final trick is to locate the outdoor air sensor for the boiler in a location where winter sunshine can hit it.  This runs counter to what you will see in the boiler manual, but allows the system to better anticipate demand.



Unless this is a large house, you are going to have trouble finding a boiler small enough for the load.  DO NOT OVERSIZE THE BOILER.  We have ended up with electric resistance boilers on several similar jobs of late (Thermolec makes the only one I know of with outdoor reset control in a ~20k BTU size.)

Robert_H

Hot Rod

Nice work! Is that a hydronic radiant headboard and foot board that you made? 

hot_rod

thanks

The bed frame circulates from the front leg, down the side rail, across the foot board, up the other side, across the headboard and back down the front leg.



The copper harp has mineral oil and a 300W immersion element, Ranco setpoint control. Great for warming jackets and hats.

SENWiEco

High Mass off table

First of all - I am not getting notification of the responses.  Does this site send out emails on each response or is the only notification through the RSS feed?



Second I want to provide a FYI:  High Mass Floor Panel is OFF the table.







This would exceed my floor truss plan ratings and require a redesign of

the entire floor truss assembly and wall locations. I am using TriForce

floor trusses that have a 22ft span in a 11-7/8 depth (industry

leading) and am way too far along to change up now. A high mass floor

would also switch me to 'heavy construction' category in the new seismic

requirements added to our local building code this month for the

Vancouver BC region. This would reduce the spacing of my braced wall

bands (by close to a 10ft reduction) and again mean a complete redesign

of the space. Not going to happen at this point.











Right or wrong, I made a decision at the beginning of this project to utilize a low mass system and it is too late to change.



Carl - thanks for the welcome. Yes trying to design system with as low design temp as possible to allow the ASHP and Solar Collectors to shine.  I was warned off Uponer joist track by some resent research.  Too much of a gap between pipe and plate (poor transfer of heat) and not a good capture so pipe moves under expansion and contraction and 'clicks'.  Comments?



Hot Rod - thanks for the first hand experience. Love the copper foot and heat board.



Mark - Yes will have HRV - But I am firmly in the school that this should be a separate system even if you have forced air from both an energy efficiency POV as well as an effectiveness POV.  Totally agree my next step is load calc and this will be implemented as soon as I get my Variance application in on Monday.



Radiant ceilings is currently my bias for the basement and 1st floor and walls and floors in baths for upper floor. Thanks for first hand experience.



SWEI - yes based on comments here and on other forums I do suspect I will be well below 100F.  Good idea on Zoning.  Agree with boiler.  Thats is why I am using an ASHP

SWEI

Notification of responses

Below the last reply at left of the frame, there is a "Subscribe to this thread" button.

SENWiEco

Subscription

Thanks Swei.



I am subscribed, but that is only a RSS feed.  I am used to LinkedIN where you also get an email for each posting on a thread you are subscribed to.  I suspect that functionality is not on this site.  No worries - just want to know what to expect.

SWEI

When I subscribe

I get emails.  Are you clicking on a button that links to http://www.heatinghelp.com/forum-thread-susbcription/148389/yes ?



There is an RSS feed at the top of the forum that links to http://www.heatinghelp.com/forum/rss

Bob Gagnon plumbing and heating

Run Extra Radiant

I would put some in the floors, ceilings and a wall behind the living room couch, having extra will allow you to run at lower temps, and if you get solar you could use some of the radiant only for solar. Solar becomes much more efficient if you can run the space heating throughout the winter, instead of just the shoulder season. Being able to run your boiler and solar with two separate systems, at the same time, will allow you to do that. Are you installing Granite countertops? That's a great slab of stone to deliver radiant heating.



Thanks, Bob Gagnon

SENWiEco

No Granite

Hi Bob - thanks for the response - no no granite.  Counter will be a form of Arborite and breakfast bar will be large slab of wood.  But I like the granite panel for houses that have that.  I will heat the walls around the shower and towel rack warmers as the more interesting locations. 



I do plan on over-sizing the panels so I have a lower temp requirement but suspect even with oversized panels I will not need even close to the whole wall or ceiling surface.



"Solar becomes much more efficient if you can run the space heating throughout the winter, instead of just the shoulder season."  Can you expand on this and your comment to run the solar separately?  Are you saying pipe up a totally separate system for the solar so that it can operate at much lower temps?  Would an ASHP not run at the same lower temps as a Solar system and therefore be compatible with it.



Again - remember my heat load will be LOW.  I am expecting to need less than 15K Btu for the entire 3700 sq ft house.

Bob Gagnon plumbing and heating

Redundant Systems

I would run twice the radiant that I need to cover the heat load. When most people do solar space heating they use a complicated piping system to heat with solar, when solar is enough to cover the whole heat load, usually in the spring and fall, this is called the shoulder season. Then in the winter the heating is provided by a boiler, or other source, and the solar is used just for domestic hot water. If you have a separate radiant system, you could supply part of your heating needs throughout the whole heating season with solar, and the rest with your boiler, at the same time. When you do this you are harvesting lower temperature hot water from your solar panel, compared to domestic hot water temps, making the panel much more efficient.



Thanks, Bob Gagnon

SENWiEco

Duplicate System

Bob -  Are you are suggesting I duplicate my system and run one on solar and the other on ASHP and then run just the solar during shoulder months and both systems during the winter?



Not sure how well this would work.  Our solar in the spring and fall is VERY limited for one, and the heat would typically be needed at night when there was no solar.  I also will be struggling to afford one set of loops little alone two.



Please clarify if I have not understood you. 



I see the solar offsetting the DWH during the summer so that the ASHP generally does not have to run for just DHW production.  During the fall we are warm enough not to need too much heat during the majority of days (just at night), and during the spring there would really not be any significant solar (we get a lot of cloud and rain).

Gordy

More radiant surfaces or

Tighter centers on the surfaces designed for the heat loss. Of your dwelling.



The lower supply water temps can become...to a point. Then there is a point of diminishing returns . But if you are trying to achieve a goal sometimes that can be over looked.





Me myself I have radiant ceilings like Mark love them. But then through out the course of ownership I have added radiant floors to certain rooms. So some of my rooms have floors, and ceilings. This allows a much lower SWT to off set the same room heat load.

Bob Gagnon plumbing and heating

Where Are You Located?

You don't get much sun in the spring and fall?



THANKS, Bob Gagnon

SENWiEco

North Vancouver British Columbia

Bob - our 'summer' will typically extend through September.  September will be cooler but generally sunny.  The much cooler weather and rains typically sets in as of Oct and by end of Oct we are typically freezing.  We hover between -5C and 8C from late Oct to late Feb.  If there is sun, it is typically on the coldest days in Dec and January.



This year has been a bit of an anomaly and we had a greyer Sept than usual but then a lovely sunny October.



Here is the sunny hours we have had since mid September (based on a min of 100 W/m2 solar energy).  I downloaded these from my weather station.



Total Hours of Bright Sunshine 15/12/13



Total Hours:  298.4

Start Date: 15/09/13

End Date: 15/12/13

Threshold: 100 W/m²



 Hours for last 15 days...

15/12/13    0.0

14/12/13    0.0

13/12/13    0.0

12/12/13    0.0

11/12/13    0.5

10/12/13    0.0

09/12/13    0.0

08/12/13    2.7

07/12/13    0.0

06/12/13    0.0

05/12/13    1.4

04/12/13    3.3

03/12/13    3.3

02/12/13    3.7

01/12/13    1.2