[TRNSYS-users] [TRNBuild] max heat load calulation

JUAN FRANCISCO BELMONTE TOLEDO JuanF.Belmonte at uclm.es
Thu Jul 2 10:37:10 PDT 2015


Dear David.

Did you active the heating and the infiltration types of your building?, as indicated in the manual. It is not clear from your last part of the mail (the note).

The approach behind this calculation is very simple, TRNBUILD is looking for a sort of steady state calculation of your building using a transient tool, then an entire month is simulated (a large cold night of 31 days) with the mínimum temperature maintained at all times, this way even a very massive Wall will forget the initial conditions (initial temperaturas of the layers).

Regards.


________________________________
De: TRNSYS-users <trnsys-users-bounces at lists.onebuilding.org> en nombre de David Geiger <david-geiger at web.de>
Enviado: jueves, 2 de julio de 2015 15:19
Para: trnsys-users at lists.onebuilding.org
Asunto: [TRNSYS-users] [TRNBuild] max heat load calulation

Dear all,

I would like to use the function "max heat load calculation" in TNRBuild for a fast comparison
with my manual calculations using the DIN guidelines.

The usage of the function itself is not the problem, as that is well explained in the manual.
My questions arise after I hit "Run TRNSYS". The simulation time is 744 h and results in
heat loads varying from 6.07 kW to 0.22 kW which leads to the following questions:

-What is the correct value for the max load or how do I obtain it using the plotted graph or the printed data?
-It seems there is a short attack phase at the beginning, is the max value the first one after the system stabilizes or just the overall highest value?
-What is the general approach behind the calculation or why is there a varying result at all, since (as far as I understand it from the manual) all variables are fixed and hence there should only be a single result?

As a potentially important side note: The building was created using the wizard for multizone buildings,
with the default options and thus contains the predefined configurations such as "no heating", "no cooling", "no (natural) ventilation" and the LEAKY infiltration type. The initial room temperature is 20°C an it is just a single zone.

Thanks in advance!

Regards,
David
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