Re: [EnergyPlus_Support] 3 questions

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

On 13 May 2003, at 13:58, Anna Chow wrote:

> Hi, All,
> I have the following 2 questions:
> 
> 1. To simulate a zone that all "envolope" walls are not exposed to
> exterio environment but interior environment (an air conditioned
> space), how to difined the surfaces:heat transfer? especially the
> following field:
>     ....
>     ExteriorEnvironment,     !- OutsideFaceEnvironment
>     ,                        !- OutsideFaceEnvironment Object
>     NoSun,                   !- Sun Exposure
>     NoWind,                  !- Wind Exposure
>     ....

To model as an adiabatic surface, assuming the adjacent space is at 
the same or nearly the same conditions as the space you are modeling:

  Surface:HeatTransfer,
    Surface_10,  !- User Supplied Surface Name
    WALL,  !- Surface Type
    PARTITION06,  !- Construction Name of the Surface
    EAST_ZONE,  !- InsideFaceEnvironment
    OtherZoneSurface,  !- OutsideFaceEnvironment
    Surface_10,  !- OutsideFaceEnvironment Object (itself)
    NoSun,  !- Sun Exposure
    NoWind,  !- Wind Exposure



> How about the exposed space is kept at certain temperature, how to
> specify that effect?

Two options:

Model another zone that is conditioned to the desired temperature, or 
use OtherSideCoefficients.

> 
> 2. If the chilled water supply is done by 3 parralel pumps, the pumps
> start/stop depends on the load. How to model the plant loop? It seems
> that it only allow 1 mixer (or splitter) in each loop, but to model
> the parralel pumps, it has to allow more than one mixer(splitter) in
> the plant loop.

If I understand correctly what you are describing, you would need to 
model this as a single variable-speed pump with a power curve that 
approximates the stepped power consumption of the three pumps.

> 
> 3. For a constant COP chiller, is there a way to schedule the chilled
> water outlet temperature, so that in the night it supply lower
> temperature water with lower COP, and in the day it supplys higher
> temeperature water with higher COP?

The constant COP chiller is very very simple and it's COP will be 
constant no matter what the chilled water temperature is.  If you 
want a chiller that responds to chilled water temperature, then use 
CHILLER:ELECTRIC, or use 2 different constant COP chillers, one 
scheduled to run during certain times and the other scheduled to run 
at other times.  To control the chilled water outlet temperature, use 
the Loop Temperature Setpoint Schedule on the PLANT LOOP object.

Mike


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