Type 19, Wall Modelling - Z-transfer function

["Benoit Sicre" <benoit.sicre@xxxxxxxxxxxxxxxxxxxxx>]

Dear All

My goal is to model a special kind of solar passive house, featuring a
quite constant indoor temperature over the rooms. That is why I decided
to use type 19 as a first approximation. Unfortunately the ASHRAE wall
catalogue delivered with TRNSYS offers no kind of wall matching passive
house yearly heat space heating requirement (according German
regulation). I had to model myself the solid compound walls. For this, I
used the b,c and d coefficients provided by PREP. Unluckily, I observed
following phenomenon:
  Despite freezing outdoor temperature and cozy 21 deg. Celsius indoor,
after a couple of time steps my walls re-emitted a huge amount of energy
back into the room (i.e. the heat flux through walls mistakenly went
opposite, that means I observed heat gains instead of heat losses
through walls).
  Any explication, any guidance out there ?

I will be very appreciative for any assistance.

I appended here additional information:

WALL DESCRIPTION (respectively length(m), heat conductivity (KJ/h-m-K),
density and specific heat

Outside wall resistance: 0.01638
Finish: 0.0125 2.88 1922 .84
Insulation layer: .32 .144 91 .84
Lime sand brick work: .15 3.56 2002 .92
Inside plaster: .0125 1.26 1249 1.09
Inside wall resistance: .1044

Coefficients provided by PREP:
   0          .0000000      8.3765770      1.0000000
   1          .0000000    -26.8543900     -3.1341550
   2          .0000007     33.7374200      3.8412400
   3          .0000192    -21.2426800     -2.3514930
   4          .0000995      7.1570540       .7663302
   5          .0001434     -1.2897260      -.1323513
   6          .0000691       .1218972       .0117693
   7          .0000119      -.0059488      -.0005253
   8          .0000007       .0001414       .0000108

Their implementation into my deck file:
UNIT 19 TYPE 19 1 Room Passive House
Param 13
* Mode Va  K1  K2 K3 Cap   N To wo     Tmin        Tmax wmin  wmax
  1    423 0.5 0  0  2000. 9 20 0.0075 T_room_set  145. 0.007 0.008
Inp 11
* T_a   w_a   T_v   mdot_v  w_v   w_I  N_people  Iact  Q_IR   Qint      
Wind
  9,2   0,0   13,1  13,2    0,0   0,0  42,2      0,0   0,0    126,8     
9,7
  0.    .0075 22.   204.    .0075 .25  4         4     600    0.0       
0.
* Walls south,east,north,west
PAR 50
* # Type   A    rau  alpha  I  hc     Nb     Nc   Nd
  1  1    46.75 0.7  .8     4  9.58   9      9    9
*bn
.0 .0 .0000007 .0000192 .0000995 .0001434 .0000691 .0000119 .0000007
*cn
8.3765770 -26.8543900 33.7374200 -21.2426800 7.1570540 -1.2897260
.1218972 
-.0059488 .0001414
*dn 
1. -3.1341550 3.8412400 -2.3514930 .7663302 -.1323513 .0117693 -.0005253 
.0000108
  2 -1    81.37 

....

Kind regards

Benoit


-- 
Benoit SICRE

>> Take a look at our new Internet-site at http://www.tu-chemnitz.de/~sicre <<

Theoretical Physics especially Computational Physics
Technical University of Chemnitz
Institute of physics
D-09107 Chemnitz
Germany

Phone: (49) 371-531-3550
Fax:   (49) 371-531-3233

http://www.tu-chemnitz.de/~sicre