Hello Cristian,

Based on the questions you are asking, I'd suggest you rethink what you are simulating.

For example, if you have a 15 story building that you are simulating that is not surrounded by neighboring buildings that shade any portion of the building, then you only need describe the first floor, the top floor and a typical floor between the two. The rest of the floors in the building are then a multiplication of the "middle" floor. I believe if you look at the generic multistory office building in Equest you'll see a file that does just this.

There are several points to be made here. First, in a multistory building, the copying of the middle floors works well to estimate the overall energy use of the building if all conditions within the whole building are similar (i.e., internal lighting loads, thermostat settings, etc.). If not, then the trouble begins, and sometimes when all is said and done, it is not worth the effort to get into the all the details for a proposed building that may or may not be built the way you're simulating it in such detail.

Second, if you do have to get into the details about every single floor (i.e., if you really, really know what's going to be in the proposed building), then you'll need to use layered walls and floors between each floor that represent the actual construction material AND you'll need to switch on the Custom Weighting Factors (i.e., if you're using Equest or some other version of DOE-2) to get a better calculation that includes the thermal mass.

Third, don't forget to put some thought into the type of systems you'll be putting into the building, since a mistake in a system parameter can easily change a building's energy use by 100 to 500%, whereas all the effort to sort out the walls, windows, floors, etc., rarely changes a building's energy by more than +- 50 to 100%.

Fourth, if in doubt, use the templates that come with Equest (or whatever program you're using), and use the default values to get something running quickly to begin checking values against some other baseline (i.e., EPA portfolio manager, CBECs, etc.). This can save you lots of time to get a rough idea of what your building is apx. going to deliver.

Finally, if you do go so far as to have to size the system in the building, then you really will need to carefully account for each known variable in the proposed building, or perhaps use a system sizing software that uses peak load condition calculations such as CLTD/CLF or RTS (i.e., Trane TRACE, etc.)

Jeff

Jeff S. Haberl, Ph.D.,P.E.,FASHRAE,FIBPSA,