[EnergyPlus_Support] Re: Slab program equations

["Ooi" <ooi_kb3@xxxxxxxxxxx>]

Are you interested in the losses 'through the ground' or 'through the floor to ground'?

Assuming it is the later, 'Relative' is an appropriate word, since the heat transfer depends on the temperatures on both the inside and outside faces, of, the floor, in the case of the slab program. 

The slab program assumes that the indoor air is kept at a fixed temperature. In other words, this means the indoor air is conditioned. So the slab program is not appropriate to use for naturally ventilated buildings. 

For precise results, iterative processing is required. This means that after the first assumed inside face temperature is used to get the outside face temperatures output from the slab program, the outside face temperatures, which are then used, as inputs into the GroundTemperature:BuildingSurface object, to find the inside face temperature. If this is not close to that first assumed, you have to use the slab program again, with a better assumed inside face temperature.

Iteration is not done if the Slab program is not used as a preprocessor, but the inputs are entered directly into the IDF   

The slab program can also generate core and peripheral temperatures, which are useful if the floor area is large.

regards
ooi

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "FrancescoP" <direzionecontraria@...> wrote:
>
> For a research, I'm interested in comparing different methods to model the heat losses through the ground. I'm wondering whether I could know the equations which are used in the slab program, in particular the equations relative to the temperature below the ground layer, please.
> Best regards
>




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