[TRNSYS-users] Tank - energy balance

[Amaia Zuazua Ros]

Hi,

Thank you all. I had the timestep for one hour, I have reduced it to 0.1
hour and now the difference between the energy to the load and energy to
the source has been reduced considerably (taking one month, earlier the
difference was 1.24 MWh and now is 0.2 MWh). Yet, I have a question, I am
simulating an office building, where the cooling demand is specially high
in summer season but still there is some demand during winter. In winter
there are some peak demands from the chiller where the tank is enough to
absorb the heat from the condenser, then, how is this translated in the
results?

Best regards,
Amaia


El lun., 8 oct. 2018 a las 17:18, David BRADLEY (<d.bradley at tess-inc.com>)
escribió:

> Amaia,
>
>   There could be two things I think. First, you're right that you need to
> take into account the change in energy stored in the tank. Type4 has an
> output that you can use. Second, make sure you are using a small timestep
> (maybe 5 minutes). With large timesteps you often get problems with energy
> balances.
>
> kind regards,
>
>  David
>
>
>
> On 10/07/2018 13:57, Amaia Zuazua Ros via TRNSYS-users wrote:
>
>
> Hi TRNsys users,
>
> I am simulating a water to water chiller coupled to two storage tanks one
> each side of the chiller. It's the first time that I work with tanks (I'm
> using type 4), and I understand that the energy balance should be
> accomplish, I mean, the total energy coming from the source should be the
> same than the energy going to the load, but this is not happening in my
> case with the condenser side of the chiller (the annual totals have
> around 10% difference) and still the system seems to work (the idea is to
> simulate a radiative system that dissipates the heat from the condenser). I
> don't know if it can be related to the internal energy change of the tank.
> Could some one give a bit further explanation/information about this?
>
> Thanks in advance!
>
> Amaia
>
>
> _______________________________________________
> TRNSYS-users mailing listTRNSYS-users at lists.onebuilding.orghttp://lists.onebuilding.org/listinfo.cgi/trnsys-users-onebuilding.org
>
>
> --
> ***************************
> David BRADLEY
> Principal
> Thermal Energy Systems Specialists, LLC
> 3 North Pinckney Street - suite 202
> Madison, WI  53703 USA
>
> P:+1.608.274.2577
> F:+1.608.278.1475d.bradley at tess-inc.com
> http://www.tess-inc.comhttp://www.trnsys.com
>
>
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