Re: [TRNSYS-users] Active Layer Matlab Model

[David BRADLEY <d.bradley@tess-inc.com>]

Daniel,

Usually the way we have done this is to use two BOUNDARY surfaces in the Type56 model. Thes boundary surfaces pass there QCOMO values (outputs from Type56) to our model. Our model computes the temperature of the layer in between the two BOUNDARY surfaces and passes that back to Type56. 

It is not uncommon to need a time delay component (such as Type93 or Type661) to delay the temperature that is passed back to Type56. Something similar may be needed in your case. If you do use the time delay then I'd advise keeping your time step short so that the interaction is still occurring on a realistic time basis.

kind regards,

 David

On 07/11/2018 20:18, Weber Daniel via TRNSYS-users wrote:

Dear TRNSYS users,

I am modelling a 3D multizone building with Type 56. My building has exotic TABS which cannot be defined with the standard TRNSYS model, therefore I am modelling them in MATLAB with an adjusted RC model.

My TABS lay between the first and second level (in the floor of the second level/ceiling of first level). Thus, there is one heat flux going into each room (above and below). I tried to input my heat flux from the TABS MATLAB model as a heat gain to the inside surface of the floor of the second level and to the ceiling of the first level. These two surfaces are modelled as massless layers with a maximum R value, to prevent any heat flux going through, as all heat flux calculations going through these layers are calculated in my MATLAB model. I have attached a picture showing the setup.

Unfortunately I am getting covergence errors in the first time step.

I don't want to input my heat fluxes directly to the air node, as I would like to take advantage of TRNSYS sophisticated radiative and convective heat transfer calculations. Additonally, I think this wouldn't be precise as the surface temperature of my TABS surfaces are greatly affected by its heat flux.

Any suggestions what the problem could be or how else I could implement this?

Thank you for your helps and best regards,

Daniel Weber

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