[Equest-users] Radiant slab cooling in Equest

Wed May 29 00:07:00 PDT 2019

Thank you for the detailed reply. 

    On Wednesday, 29 May 2019 2:43 AM, Nicholas Caton <Nicholas.Caton at se.com> wrote:

 #yiv0410933120 #yiv0410933120 -- _filtered #yiv0410933120 {font-family:Helvetica;panose-1:2 11 6 4 2 2 2 2 2 4;} _filtered #yiv0410933120 {panose-1:2 4 5 3 5 4 6 3 2 4;} _filtered #yiv0410933120 {panose-1:2 11 4 0 0 0 0 0 0 0;} _filtered #yiv0410933120 {font-family:Calibri;panose-1:2 15 5 2 2 2 4 3 2 4;} _filtered #yiv0410933120 {panose-1:2 11 4 0 0 0 0 0 0 0;}#yiv0410933120 #yiv0410933120 p.yiv0410933120MsoNormal, #yiv0410933120 li.yiv0410933120MsoNormal, #yiv0410933120 div.yiv0410933120MsoNormal {margin:0in;margin-bottom:.0001pt;font-size:11.0pt;font-family:sans-serif;}#yiv0410933120 a:link, #yiv0410933120 span.yiv0410933120MsoHyperlink {color:#0563C1;text-decoration:underline;}#yiv0410933120 a:visited, #yiv0410933120 span.yiv0410933120MsoHyperlinkFollowed {color:#954F72;text-decoration:underline;}#yiv0410933120 p.yiv0410933120msonormal0, #yiv0410933120 li.yiv0410933120msonormal0, #yiv0410933120 div.yiv0410933120msonormal0 {margin-right:0in;margin-left:0in;font-size:11.0pt;font-family:sans-serif;}#yiv0410933120 span.yiv0410933120EmailStyle19 {font-family:sans-serif;color:windowtext;}#yiv0410933120 .yiv0410933120MsoChpDefault {font-size:10.0pt;} _filtered #yiv0410933120 {margin:1.0in 1.0in 1.0in 1.0in;}#yiv0410933120 div.yiv0410933120WordSection1 {}#yiv0410933120 The advent of explicit DOAS system modeling with the most recent eQuest build presents some new opportunities that we didn’t have previously for handling radiant slab systems.  To add to your assertions around fan coil fan energies, ventilation loads and fans were still something to consider and account for – now we can handle those explicitly as a separate system!    The key thing to continue considering in modeling radiant heating/cooling slabs/beams in eQuest is the fundamentals around a doe2 zone being assumed as fully/perfectly mixed at all times, whereas radiant systems by their nature need to consider buoyancy effects and loads in relation to comfort zones (in elevation), relative to the total zone volume.  This is a gap to bridge in consideration of how to structure your model so that the assumptions of design regarding loads incident on the system are in alignment.  A tool in your belt here is that you can reduce the conditioned volume of your zones by playing with the geometric height.  Alternatively/additionally, you have inputs available to rigorously specify/adjust the fraction of internal loads incident on the conditioned volume.    I think autosizing the airside system cooling capacity and airflow rates remains generally acceptable practice, but you should probably minimally make time to check and reign in the hydronic cooling capacity observed at the associated plant chiller(s). If the goals of the model extend to/include accurately assessing comfort criteria, I might however make a point to further assess and limit cooling capacity in each zone based upon the radiant slab/beam design criteria.    In all this though, folks simulating radiant systems today can be thankful they don’t have to “layer in” a DOAS approximation on top of the usual shenanigans!    ~Nick     Nick Caton, P.E., BEMP 
|   Senior Energy Engineer
  Regional Energy Engineering Manager   Energy and Sustainability Services
  Energy Performance Contracting  | D  
M  
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E    | 913 . 564 . 6361 785 . 410 . 3317 913 . 564 . 6380 nicholas.caton at se.com  | 15200 Santa Fe Trail Drive
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|   |

      From: Equest-users <equest-users-bounces at lists.onebuilding.org>On Behalf Of Rathna Shree via Equest-users
Sent: Tuesday, May 28, 2019 5:40 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Radiant slab cooling in Equest    [External email: Use caution with links and attachments]   Dear All,    I read a lot of posts regarding this subject. Since Equest is not capable of directly modeling Radiant cooling, the work around would be to model with a Fan coil unit with fan energy at 0 Kw/cfm. The question is, what should be the supply air CFM and cooling capacity of FCU that should be modeled. Should it be left to autosize?    Looking forward for a right modeling approach.    Thank you.    Regards, Rathnashree 
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