Dear TRNSYS users,
I am using TRNSYS to model air conditioning system with DOAS and compare it with radiant chilled ceiling (see fig1 in 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 inner surface node (might be stored in the wall, going to a slab cooling or directly transmitted)” as per 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 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 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 attached files.
Should b6_comin_1 and Q_N be equal or not. What are the factors that make them different?
Attachment:
fig 2.JPG
Description: JPEG image
Attachment:
fig 3.JPG
Description: JPEG image
Attachment:
fig 1.PNG
Description: PNG image
