How to simulate a certain floor of a building

Hello.

(This may be basic question,) I would like to ask you two questions about simulating a certain floor of an office building using EnergyPlus.

(1) How to model ceiling and floor of a room adjacent to conditioned rooms.

I came up with the following two ideas.

Set the boundary condition: adiabatic
Enter the same model on the upper and lower floors

I think 1. is the simplest, but I am worried that the heat capacity of the ceiling and floor slabs is properly added. Please let me know if there is an officially recommended way.

(2) How to model ceiling and floor of a room adjacent to unconditioned rooms.

In our country, we use “adjustment factor” to roughly give the temperature of the next room in the load calculation. Is it possible to set such boundary condition in EnergPlus? (I also thought about entering zones as (1)-2., but I’m not sure how appropriate the ambient temperature of the unconditioned room will be. )

Also, I would like to run this simulation with a simple model as much as possible.

R-Fujiwara

asked 2021-10-13 20:57:33 -0500

14.1k

Aaron Boranian

updated 2021-10-14 08:08:02 -0500

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If you're explicitly modelling every floor of a building, the ceiling surface of a zone should simply connect the above floor surface as boundary conditions, and vice versa. If you're instead only modelling a sample floor (without zones below/above) and using floor multipliers, then both of your options are "OK" (either floor & ceiling surfaces are adiabatic, or floor surfaces connect the above ceiling surfaces. The floor construction should reverse/match the ceiling construction. Heat will be stored in your floor/ceiling constructions, even under adiabatic conditions.

To your 2nd question, would this still be linked to the use of floor multipliers? The answer would depend on what's taking place inside the unconditioned zone (processes or lighting loads in there?), the boundary conditions of the other surfaces of this unconditioned zone (facing outdoors? or simply facing other conditioned zones?), etc. Need to know more before venturing a suggestion.