I am using TRNSYS to model the air conditioning system with DOAS and compare it with the radiant chilled ceiling (see fig1 in the attached file).
In this process, I have used BALANCE 4 - ENERGY BALANCE FOR ZONES (NTYPE 904) for finding the energy gain in the zone.
B4_QBAL =- B4_DQAIRdt + B4_QHEAT - B4_QCOOL + B4_QINF
+ B4_QVENT + B4_QCOUP + B4_QTRANS
+ B4_QGINT + B4_QWGAIN + B4_QSOL
+ B4_QSOLAIR [kJ/hr]
From this, I have generated B4_QTRANS which “is transmission into the surface from the inner surface node (might be stored in the wall, going to a slab cooling or directly transmitted)” as per the TRNSYS manual. I printed “B4_QTRANS”, which is the heat flux in the zone via the building envelope as per my understanding.
And
I also used BALANCE 6 - ENERGY BALANCE FOR SURFACES (NTYPE 906) for finding heat flux in the room via the surface.
B6_BAL = - B6_DQWALLdt – B6_QCOMI + B6_QCOMO + B6_QRADGI
+ B6_QRADGO - B6_QALG [kJ/hr]
;
B6_QCOMI combined heat flux to inside (going into zone+; going into the wall -)
I generated the heat flux inside the room from all the surface (6 surfaces) and summed them up and let this be Total_wall_in.
Now, from this, I have some questions.
My first question is
(1) “What is the difference between B4_QTRANS and the sum of – B6_QCOMI from all the surfaces (Total _wall_in)?” Shouldn’t they be the same? (plot as fig 2 in attached file)
I tried to see the difference between the heat flux from the zone balance B4_QTRANS and Total_wall_in(sum of B6_comin from all the surfaces) and got the following plot.
My second question is
2) For the surface balance I plotted B6_QCOMI , B6_QRADGI, inside and outside temperature of the surface. I calculated the heat flux via Q = U(TD) and plotted it as well. The plot is shown in fig 3 of the attached files.
Should b6_comin_1 and Q_N be equal or not. What are the factors that make them different?
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