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When is Delta T for heating not a true Delta T??

Mark Eatherton
Mark Eatherton Member Posts: 5,858
in THE MAIN WALL
When the sky has no clouds!



Take a look at this photograph. I took it early in the morning, before any solar influence, and the lowest OSA temp seen that night was -3.5 degrees F.



I've had hotel mechanical engineers up here in the mountains tell me that their decision as to whether they need one boilers or two was based more on whether there were going to be clouds that night versus the lowest air temperature potential.



Interesting stuff to say the least... Comments?



ME

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Comments

  • Mark Eatherton
    Mark Eatherton Member Posts: 5,858
    Picture

    here

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  • Mark Eatherton
    Mark Eatherton Member Posts: 5,858
    Radiant windows from theoutside...

    As viewed from 75 feet away...

    Furthest right window off, next two running at 90 degrees F, next three running at 80 degrees F, and last four on left running at 70 degrees F (Thermally opaque condition).



    ME

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  • Mark Eatherton
    Mark Eatherton Member Posts: 5,858
    edited December 2009
    Radiant windows form the inside...

    Far left window off, balance of them are on with some hotter than others (obviously). The furthest windows are in the thermally opaque mode, maintaining around 70 to 75 degrees F. In other words, as it pertains to conventional room heat loss, they are not there... and this is what I think is the MOST efficient mode.



    Induced R value :-)



    Anyone care to tender a guess as to what R value of window would be required to maintain a room side surface temperature of 70 + degrees F?



    ME

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  • Mark Eatherton
    Mark Eatherton Member Posts: 5,858
    edited December 2009
    Picture one

    For some reason, I can't post two pictures at the same time,,,



    Figured it out. I was trying to attch th IR extenion file photos and not the JPEG extention photos...



    My bad :-)

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  • CMadatMe
    CMadatMe Member Posts: 3,086
    I'll Give It a try

    I have a questions first. What time value are you stamping on that room side temp?

    Ti-To divided by R-Value = Heat Loss of an outside panel

    Ti = Temp Indoor

    T0= Temp Outdoor

    I would have to have a R-value that exceeds Ti in order to have no loss at all. But I'll bite and say. For under 15 minutes a 2.77 for 3 minutes a .55

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  • Mark Eatherton
    Mark Eatherton Member Posts: 5,858
    Sure....

    One hour, Ti of the glass is 70 degrees F, and To of the glass is 0 degrees F, same as the OSA.



    Un-energized, the glass has a conventional R value of 2.5, and the corresponding glass surface temeprature at zero degrees F was 55 degrees F.



    What do you think the R value would be?



    ME



    PS, What about the glass that is 90 dergees F? Same other parameters.



    ME

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  • CMadatMe
    CMadatMe Member Posts: 3,086
    I''ll have to think

    this out throughout the day. I'll get you an anwser tonight. Buys day today..Alot of no heats.

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  • bob_46
    bob_46 Member Posts: 813
    edited December 2009
    Delta T= change in trickyness

    Mark, I think this is a trick question or at least a tricky one. First, R factor is the reciprocal of U factor by definition. U is the amount of heat transfered in BTU/hr/sq.ft/ Fº ∆T. If the temperature of the window is 70 Fº and the space is 70 Fº the ∆T = 0 , so U =0 there is no heat transfer from the space to the window. The R factor would be infinite. To determine the amount of heat given off to the out side air just measure how many watts gozinta the window and multiply by 3.413 BTU.

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  • Mark Eatherton
    Mark Eatherton Member Posts: 5,858
    Great minds think alike bob...

    But I have told everyone involved with the project to not use those terms, because it causes professional to do a double take, and curl their noses....



    But essentially, it is what it is, adjustable and infinite.





    ME

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  • Unknown
    Unknown
    Blowing Your Own Horn,,,,

    Geezze Mark,,,,, 7 out of 10 postings are yours,,,, give your ego a rest,,, please!
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,858
    If I don't blow it, who will....

    And I have no ego Dave. Only a desire to educate, and not criticize like some people....



    Who's counting? Who's commenting?



    If you had something as hot as these windows, you be honking about it too.... ;-)



    And you don't have to read anything I write. Just ignore my posts.



    ME

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  • TonyS
    TonyS Member Posts: 849
    How many watts are

    those windows using?
  • Unknown
    Unknown
    No Ego???

    Holy-heck everyones focused on "The Great ME" I would think,,, but there comes a time.



    Personally, i think no-one but yourself gives a damn for products your promoting, & yourself,,, in thinking of your superiority.



    I DO choose not to read your posts,,,,, but you post SO-OFTEN avoiding you is not a luxury I can afford myself as much as I would like.
  • MIke_Jonas
    MIke_Jonas Member Posts: 209
    Keep posting Mark!!

    I read your stuff every time I see your name.



    I think about you almost every day...in a purely hetero, Viking sort of way..let me 'splain...



    My office is in the front of my house. West side of Chicago (Berwyn). I have a 5 1/2' x 5 1/2' single pane window, with a transom like 5 1/2' x 18" single pane window above it.



    I don't need no stinkin' R values to tell you the chill I feel as I sit at my desk do I?



    So I meet you at Rexpo in Schaumburg and see/touch/feel your window display, in a purely hetero, Viking sort of way. Blows me away. The possiblities are endless. MegaMillions Lottery is something like 166 jillion tomorrow night, savi?



    So, every morning, in winter, I walk into my office and say to myself..."Dang, I got to remodel this room and get me some of them ME windows in here."
  • CMadatMe
    CMadatMe Member Posts: 3,086
    Keep Up The Great Work Mark

    I enjoy your posts. Keeps the mind fresh. I was stumped on this one. Keep up the great work.

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  • Mark Eatherton
    Mark Eatherton Member Posts: 5,858
    Tony S....

    Bear with me. I just pulled the data loggers from the site and have a LOT of information togo through and decipher. I will be able to answer your question shortly for two different modes, one for opaque condition (maintaining the glass at around 70 to 75 degrees F) and the other at a higher thermally productive mode.



    Thanks for your patience.



    Just like with hydronics, the only correct answer to any question is, IT DEPENDS! What size of glass under what operating conditions.



    Bear with me.





    ME

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  • Mark Eatherton
    Mark Eatherton Member Posts: 5,858
    Chris...

    I've been stumped for almost three years :-)



    Thanks for the input.



    ME

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  • NRT_Rob
    NRT_Rob Member Posts: 1,013
    dave, you're wrong

    many of us out here are interested in mark's radiant windows and what they can do.



    If you are not, ignore the whole thread. easy.
    Rob Brown
    Designer for Rockport Mechanical
    in beautiful Rockport Maine.
  • L'town Radiant_2
    L'town Radiant_2 Member Posts: 39
    Dave needs

    an attitude adjustment....if you don't have anything nice, just don't say anything.

    Mark, I recall seeing you display this product at the RPA show last year, It was impressive but it didn't have hot water running through it so I didn't spend much time on it. I'd have to say that this definately deserves some more consideration. Can you direct me to a website where I could study up on it?

    Oh, and I'm always glad to see a post by the "Great ME"

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  • DanHolohan
    DanHolohan Member, Moderator, Administrator Posts: 16,598
    Nasty, Dave.

    You're disappointing me.
    Retired and loving it.
  • TonyS
    TonyS Member Posts: 849
    This will be interesting!

    Keep us informed. I would imagine there are uses for this glass beyond buildings. Like a zoo or aquarium,terrarium that houses tropical type animals. And Dave, this stuff is interesting!!, and Mark is always willing to share, so let him alone.
  • bill garnett_2
    bill garnett_2 Member Posts: 21
    Radiant Windows

    ME,

    I have not posted since the walls new format-I love your post's !!! Always informative not sure why Dave is so jealous ?
  • Gordy
    Gordy Member Posts: 9,546
    edited December 2009
    I for one

    Appreciate Mark sharing the information he has collected on these radiant windows. Been following his threads on these since his first posting of them. Been following his threads since I first found this site 10 years ago.



    Mark always has something PRODUCTIVE to say, and share on everything.....I do not believe sharing knowledge is egotistical.



    Keep posting ME





    Gordy
  • CMadatMe
    CMadatMe Member Posts: 3,086
    Knowledge is Power

    Mark I  enjot reading your posts. What makes this site great to me is the education you find in each post. I have been in the industry since 1989. So of consider this back in the day. Back then most supply houses were owned by mon and pop. There was always something educational going on. With corporations buying up these type of supply houses the of education you can get just from reading the posts here is priceless. Keep up the great work.

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  • Dave Yates (GrandPAH)
    Dave Yates (GrandPAH) Member Posts: 281
    keep on posting!

    You're one of the main reasons why I visit here. Lots of others, but I tend to gravitate to posts I can pretty much be sure will have some substance. It's my old enemy - time - as in the lack thereof.



    So, keep on posting old friend and I'll keep on reading and learning!
  • hot_rod
    hot_rod Member Posts: 23,184
    ME is very generous

    with his knowledge and experimentations, and by now you should be aware of his unique style, Dave. Lighten up, it the holidays :)



    hr
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,858
    edited December 2009
    I am humbled...

    and honored by the responses. Thank you for your support.



    I had no intention of leaving. Been here since day one and will be here till it closes (hopefully never) or they close the cover to my casket, which ever comes first ;-))



    Am just currently up to my ears in allligators, and the season. Will get back with more factual data as I get the chance.Dave, know that I hold no ill will towards you.



    ME

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  • Simply Rad
    Simply Rad Member Posts: 191
    ME for hydronic president!

    Through out the years I have found  those who do not understand tend to bad mouth.

    ME I can't thank you enough for all your knowledge and experiences! 

    Hail to hydronica. 

    By the way this site it designed to help and not harm.

    Happy Holidays



    Jeffrey
    Jeffrey Campbell
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