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Dear Trnsys Users,
I am trying to add a thermal screen to my Greenhouse model. The screens have to deploy and close based on controls.
I have seen some research work so i guess it is feasible in Trnsys.
Can anyone give me suggestions on how i can do that ?
Regards,
@sarmouk it depends a bit on the configuration of your greenhouse and of the screen.
If your greenhouse is comparatively small and the shades are deployed on the inside of the greenhouse glazing then you can treat the screens (both as a thermal resistance and as a solar radiation blocking shade) using an interior shading device.
In taller greenhouses where the screen is sometimes drawn across just above the plants but there is a good bit of air volume still above then what I typically do is to model the greenhouse as two airnodes stacked on top of each other and "separated" by an adjacent window. There are a few options in the window library for specifying a horizontal virtual/nonexistent window that does not impede solar and has no thermal resistance. Since there is a window, you can then use its interior shading device to model the screen.
As a side note, the complication of modeling the greenhouse as two airnodes stacked on top of each other is that you have to handle the convective energy transfer between the upper and lower airnode. That is not a very easy task. The best way to handle it is with either Type97 (CONTAM) or TRNFlow. Both options add a significant amount of complexity to the building model.
best,
david
