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Supplement heat for window wall.

Zman
Zman Member Posts: 7,609
  





I am working on a home with an existing radiant floor system. The floors are 3/8" pex at 12" OC imbedded in 1 1/2" gypcrete with 3/4" engineered hardwood.I have run a heat loss and am comfortable that on average the floor panels will adequately heat the room.

 

The room is very open with ceilings that vault from 12 to 20 feet. The southwest wall is mostly glass starting 30" off the floor. The glass in this area is on average 12' tall and takes up most of a 22' long wall. The glazing loss of this wall is about 12,000 btu.The 30" wall below the window will house an automatic "down blind". The wall has been firred in 6" to accommodate. The design temp for the system is is 140 degree.The controls will be tekmar tn4. The windows have the worst possible exposure, 9,500 feet on a cliff with tons of wind.

 

My concerns are;

The area in front of this wall will have a radiant cooling effect.

The heat loss will create convective cooling air flow as the cold air falls.

The floors in the surrounding area will overheat to compensate creating uncomfortable conditions.

The room will underperform at night and overshoot during the day.



The options I have thought of are;

Attach a low mass panel radiator to the front of the wall sized for the entire loss.This would provide radiant and convective heat. I am not sure I can sell the owner on this look.

Turn the front of the wall into wall radiant system "siggy's design" generating 60 btu/foot, it would produce about 3,300 btu radiant.

Turn the inside of the wall into a giant baseboard heater. I would use 2 copper fintubes like the ones installed in baseboards the entire length.I would need a slot in the top and bottom of the wall. I am unsure of the size of these slots but thought I could copy the design of a baseboard heater.I am not sure how much convective heat this would produce my SWAG is 6,000-8,000 btu for 40 feet. of fintube.Maybe some little computer cooling fans could raise the output?



Thoughts anyone?

Carl
"If you can't explain it simply, you don't understand it well enough"
Albert Einstein

Comments

  • Mark Eatherton
    Mark Eatherton Member Posts: 5,852
    edited September 2012
    You could make the windows disappear....

    as it pertains to heat loss and its cold sucking effect on the human body.



    Visit www.energizedglass.com



    Otherwise, I think you are headed in the right direct. The more radiant emitters, as opposed to convective emitters you can have, the better. The goal is to raise the MRT, which drives the bus of human comfort.



    With the windows, you could keep them at 70 to 75 degrees F on the lower sections, and not know they are there.



    ME

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  • Zman
    Zman Member Posts: 7,609
    edited September 2012
    Radiant below 30"

    Mark,

    Thanks for your insight. My only reservation about the siggy option is it is to close to the floor.

    Carl



    Nice windows! Can they retrofit?
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,852
    edited September 2012
    Retrofit, absolutely possible...

    hardest part wil be getting 120VAC to the window top header.



    Depending upon the size, you can operate more than one window on a 20 amp circuit. The controls are programmed using a wifi connection. We are working with the manufacturer of the control chip to see if we can have numerous windows "talk among themselves" so that we could use one 20 amp circuit, and operate them such that we stay below the breaker trip threshold. We'd be rotating the power between operating windows, and give priority to those windows that have been set higher in the echelon.



    We will have a really "cool" working model at the upcoming RPA/MSW trade show in Shaumberg Ill. By "cool", I mean that this particular demonstrator has an enclosure that allows us to drop chunks of dry ice into the exterior space to simulate extremely cold outside air conditions, while allowing us to heat the interior pane. If you're in the hood, drop by and we'd be glad to demonstrate it for you.



    Let me know if you need any additional information.



    ME



    EDIT: What are your concerns with radiant walls within 30" of the floor? I have it in my cabin, all the way to the floor with no problem, and my grand kids love it...



    ME

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  • Gordy
    Gordy Member Posts: 9,546
    edited September 2012
    Schaumburg

    Mark what's the date, and where in Schaumburg? I would love to get up close to this phenomina.



    Will the dry ice mock up also display lack of heat loss of the window? Or shall I say the low rate of heat loss.



    Gordy
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,852
    Here you go Gordy...

    http://www.mechanicalsystemsweek.com



    Would love to finally meet you after all these years ;-)



    I will hopefully be able to help work Energized Glass' booth during the trade show.



    ME

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  • Gordy
    Gordy Member Posts: 9,546
    Ditto Mark

    After all these years !
  • Zman
    Zman Member Posts: 7,609
    edited September 2012
    Quite fan coil

    I have considering a fan coil for this application. It would improve response times and allow the floors to stay cooler, reducing "overshoot" during the day.

    I have looked at the beacon morris kickspace heater. I think they will be to loud.

    A Unico system may be overkill.

    Any suggestions?

    Thanks,

    Carl
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
This discussion has been closed.