Re: [EnergyPlus_Support] A 5-story building setting

["Michael J. Witte" <mjwitte@xxxxxxxx>]

1.  For the zone 1 roof, you have two choices.  You can model it as 
three rectangular surfaces, or you can model it as one rectagle of 
equivalent area.  In situations like this, there are several rules to 
remember:

a)  The total roof area is critical.  This governs how much 
conduction heat transfer occurs and how much solar radiation is 
absorbed.

b)  An "opening" in the roof does nothing.  If you use an equivalent 
rectangle so that the edges of the roof do not meet the walls, 
leaving a gap, the gap does nothing.  The gap does not let air in and 
it does not let solar in.

c)  Heat transfer surfaces only cast shadows in the direction in 
which they face.  For a flat roof, it faces up, so it will never cast 
a shadow on another roof surface, even if two roof surfaces overlap.

2.  The zone multiplier is applied to zone loads as they are passed 
to the HVAC system.  The zone multiplier is applied every time step 
of the simulation.  The sizing parameter (in the sizing objects) is 
applied at sizing time only and increases the capacities when 
autosizing, but it is not applied during the actual simulation.  The 
problem you encountered may be due to a mismatch of equipment sizing 
when the zone multiplier was added.  If you cannot fix it, please 
send you idf file to energyplus-support@xxxxxxxx

Mike



On 13 Oct 2002, at 13:44, rmp4aup6 wrote:

> I am simuating a 5-stroy building, and I have some questions abou
> setting: 1. Roof setting: Like the figure, the room was divided into
> two zones (1 & 2) , how do I set the roof? (only 4 or 3 sides are
> allowed) Now, I set the roof of Zone 1 to be a rectangle that overlaps
> the roof of zone2 !!! Do you have any suggestion?
>     --------------
>     |     1      |
>     |            |
>     |   |----|   |
>     |   |    |   |
>     ----|  2 |----
>         |----|
> 
> 2. The simuation test is without problem.  But when I tried to set the
> Zone multipler to be 3 (to account for floors 2,3,4 ), but thousands
> of warnig messages show: ** Warning ** Pressure out of range (SATUP)
> **   ~~~   ** (mm/dd/hh) 7/31/09 Input Pressure= 0.68 **   ~~~  
> **?Resultant Temperature= -62.38 3. I am not quite sure about the
> meaning of sizing parameter. For example, we set it to be 1.5, does it
> mean that it simuate the 1.5 times the cooling and heating load of the
> original room? If that is the case, can we say that the room after
> setting the parameter is 1.5 times volume (space) of the original
> room?
> 
> Thank you very much.
> 
> 
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