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Hello,
I am trying to model the thermal load of a house that has its floor raised 1 meter high above the ground making the external floor exposed to ambient conditions. In Type56 floor that are in contact with ground are declared as boundary configuration with a boundary temperature and convective resistance is reduced to negligible value to infer ground contact. Now that my floor is not ground coupled, what should be my modeling approach?
1. If I declare the floor as external component, will the internal calculation of inside the floor convection coefficient be considered ideally as it would be if it was declared as a boundary component?
2. Since it is an external component, how will type 56 understand that the radiative exchange is going to be only with the ground's exposed surface (ground reflected short wave and reciprocated long wave exchange) and not the celestial hemisphere of the sky dome.
I appreciate efforts from the TRNSYS team or any community members for answering this. Thanks.
-Abir,
Grad Student, UC Davis
Abir,
1.) Yes, you can use the internal calculation for inside. However, for the outside you need to define a convective heat transfer coefficient for outside conditions.
2.) The floor shall be defined as external and it has an orientation H_0_180. Due to a surface slope of 180 the surface doesn't get direct solar radiation, but receives diffuse refelcted radiation. For longwave, the view factor to sky (FSKY) is the relevante paraemter. If it is set to 0, the surface doesn't see the celestial hemisphere of the sky dome. Longwave radiation exchange is perfomred with the given ground temperature only (Input 4). It is highly recommended to check the euqtions given in the manual (05-MultizoneBuilding.pdf) for a better understanding.
- marion
