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Bonjour,
Je travaille actuellement avec le Type 999 pour modéliser un stockage thermique enterré, et j'aurais quelques questions pour clarifier certains points :
Q1 : Lorsqu’on utilise plusieurs couches de tuyaux (2 ou plus), sont-elles considérées comme en série ou en parallèle ?
Q2 : Quand on définit la profondeur d’une couche, est-ce la profondeur jusqu’au tube ou bien jusqu’au bas de la couche de sol associée ? Autrement dit, est-ce que le tube est situé au centre de la couche ou bien à l’extrémité inférieure ?
Q3 : Pour mon étude, j’envisage une boîte de sol fermée. Le modèle ne semble pas inclure d’isolation au fond du domaine. Existe-t-il une option pour modéliser une isolation à la base ? Et pourquoi le modèle ne prévoit-il pas par défaut d’isolation inférieure ?
Q4 : En testant le modèle avec les options "adiabatique" et "conductive" pour les limites, je ne remarque aucune différence dans les résultats. Est-ce un comportement attendu, ou bien cela indique-t-il un problème dans ma configuration ?
Cordialement ,
M zaoui
If you have not already done so, I would recommend looking at the "hints and tips" section of the Type999 documentation (located in .\Trnsys18\Tess Models\Documentation\). There are some diagrams and explanations in the documentation that may help.
Q1: (if there is more than one layer, are they assumed to be in series or parallel?) It is up to the user to define the order in which the flow proceeds through the pipes. The final set of parameters numbers each one of the pipes that have been defined in the heat exchanger and asks which direction the flow goes through that pipe and whether the pipe is downstream of another pipe (and if so, which one) or whether it is an inlet.
Q2: (does the "layer depth" refer to the middle of the pipe or to the bottom of the layer that contains the pipe?) It refers to the middle of the pipe. Figure 6.5.8 might help clarify.
Q3: (is there a way to define insulation beneath the ground heat exchanger?) Not with this model. Type999 and 997 allow you to define insulation above the ground heat exchanger but not on its sides or beneath. There are other models (such as Type1267) that can be used if you have a ground heat exchanger that is enclosed in a ground-coupled insulated box. Type1267 is an individual component and is not associated with one of the prepackaged libraries.
Q4: (there does not seem to be any difference in results when I choose "adiabatic" or "conductive" for the far-field boundary condition). That is pretty normal for ground heat exchangers, especially if they are not buried too deep and/or if the far-field distances that you have chosen are a significant distance from the extents of the heat exchanger.
kind regards,
david
Bonjour, Merci à David pour la réponse rapide à ma précédente question !
J’ai encore quelques doutes et je souhaite juste confirmer certains points pour être sûr.
Q1 : Juste pour être sûr – si je prends la deuxième configuration d’échangeur de chaleur, et que je souhaite que la deuxième couche soit en parallèle avec la première :
La première couche se termine par Inlet 5, Direction 2 Donc, je commence la deuxième couche avec Inlet 6, Direction 2 pour être en parallèle
Et si je voulais que les couches soient en série, je commencerais la deuxième couche avec Inlet 6, Direction 1 Est-ce bien cela ?
Q3 : par rapport à ce qui a été dit : je pense qu'il est en fait possible de modéliser une isolation latérale (périmétrique) dans le Type 999 via la résistance thermique périmétrique .
bonne journée.
cordialement,
M.ZAOUI
Mohammed,
I am not sure that I entirely understand the pipe layout that you are trying to achieve. The figure you drew (conf2.png) for layer 1 is entirely correct and you are correct about how to do the series configuration. i.e. if you want layer 2 (below layer 1) to be in series with and to match layer 1 but in reverse then you'll define pipe 7 as having pipe 6 as its inlet and as having direction 1 (just like you describe).
I am a little less certain about the parallel configuration because I am not sure whether you want a second layer of piping exactly the same as the first layer but deeper (with its inlet in the upper left hand corner of your drawing just like in layer 1) or whether layer 2's inlet is not directly below layer 1's.
If you have two layers in parallel whose layout and flow directions are identical and the two inlets are one directly below the other then you'd have
index inlet direction
1 0 1
2 1 2
3 2 1
4 3 2
5 4 1
6 5 2
7 0 1
8 7 2
9 8 1
10 9 2
11 10 1
12 11 2
if you have a situation where layer 2's inlet is not directly below layer 1's inlet and/or follows some other flow path then you can still define it. If that is the case and you can send me a picture of how you want layer 2 to be configured then I can suggest the parameters that you'll need to define.
I think you are correct about the perimeter insulation; my apologies for my earlier incorrect answer!
David
