[TRNSYS-users] questions heating demand calculation type 56

[Arie Kalkman]

Dear Sabine,

My guess would be that your wall time-base currently equals 1 hour, and that your results will become more accurate when you use a smaller timebase?

Regards,  Arie



________________________________
Van: Sabine Jansen - BK [mailto:S.C.Jansen at tudelft.nl]
Verzonden: woensdag 31 maart 2010 15:38
Aan: trnsys-users at cae.wisc.edu
Onderwerp: [TRNSYS-users] questions heating demand calculation type 56

Dear all,

I have some general problems with a type 56 simulation, two related to the calculation of the ideal heating demand and 1 general question.


 1.  When calculating the ideal heating edmand,  it takes two timesteps for the ideal heating to reach the required temperature setpoint..
Is this normal or what am I doing wrong?

 1.  When using a schedule in trnbuild, somehow the heating only switches on at exactly the time of the switch (in my case 7 h and 17 h), while I assumed the schedule to mean that at the new time the new temperature must be obtained (see attached document). The heating switches OFF at exactly the changing time, so it then takes the new setpoint temperature. (see figure 2).

 1.  General question:  Does anyone know why the temperature seems to be fluctuating a little (in other words: it is not a smooth line) as soon as the heating turns off?
Also when using a smaller timestep the line is not smooth, but the temperatures stay constant during a hour, so the line looks like a staircase..
(note: the non-smooth line occurs when the heating is OFF)
(p.s. for some rooms the lines are more smooth than for others. I have tried different tolerances etc, but didn;t find a soluation)

All is explained in more detail with figures in the attached file. Has anyone experienced the same or has an idea what I might be doing wrong?

Thank you very much,

Sabine Jansen


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