[TRNSYS-users] help for chilled ceiling Uwrx problem

[Yujun TAO]

Dear trnsys users,I encounterd the following message when simulate a model with chilled ceiling.

*** Fatal Error at time   :         1.000000
    Generated by Unit     :    56
    Generated by Type     :    56
    Message               : multizone building -  Resistance from radiant panel Rr_Rx negativ  this might be caused by a  too high Resistance Rw (e.g laminar  instead of turbulent flow) or a too low estimated  Resistance R_WRX
 
 
*** Fatal Error at time   :         1.000000
    Generated by Unit     :    56
    Generated by Type     :    56
    TRNSYS Message    191 : Subroutine MATRIX_INVERT was called from subroutine INVPAR with a singular matrix.
    Reported information  : Subroutine INVERT was called from subroutine INVPAR with a singular matrix!

So i did some tests, i changed the Uwrx value, finally, i found that the model could turn well only when the Uwrx is lower than 110 kJ/h/m²K. But i don't understand if this value can be used. Because the value proposed in the table 5.4.5-1 for the barcol-air product is about 38 W/m², otherwise 136.8 kJ/h/m². This value should be divided by the dTsurf_norm ? The two different units for Uwrx in the Eq5.4.5-1 [kJ/h m² K] and the table 5.4.5-1 [W/m2] make me confused. If the value of Uwrx in the table 5.4.5-1 shoud be divided by the dTsurf_norm corresponded, it make sens for my tested value. If not, i really don't understand.
Aleck 



 

 
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