[EnergyPlus_Support] Re: How to model a HVAC system with both cooling and heating function?

["adahoilam" <i50447973@xxxxxxxxx>]

The HVAC system I am using was a dummy fan coil unit air system plus 
a purchased chilled/hot water system.

In the air system, I have added all necessary controllers (include 
pretreat cooling coil, cooling coil, reheating coil and heating 
coil, outside air) and set point managers, but I havent added set 
point manager for the heating coil. Do I need to add this?

I used SINGLE DUCT:CONST VOLUME:REHEAT for air supply system.

On the other hand, I used purchased water systems for both chilled 
water and hot water supplies to the COIL:Water:Cooling and 
COIL:Water:SimpleHeating, together with plant autosizing items for 
both systems.

Lastly, I have a file to do zone autosizing. And used a thermostat 
called "Dual Setpoint with deadband".

There was no problem when I used cooling only, however, energy 
sizing data were so small in the heating part when I added heating 
coil for the whole HVAC system.

Hope these information can help you to understand my case study.

Thank you for your help.

Ada

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Michael J. Witte" 
<mjwitte@...> wrote:
>
> It is difficult to know what to suggest.  What type of HVAC system 
are you 
> modeling?  What EnergyPlus HVAC and control components are you 
using?  Did you 
> add a controller and set point manager for the hot water coil?  
What type of 
> thermostat controls are you using?
> 
> Mike
> 
> 
> On 6 Dec 2007 at 7:43, adahoilam wrote:
> 
> > I am now working on a HVAC system modeling for a building in 
China, I 
> > tried to use the existing model (with cooling function only) to 
modify 
> > to a model can suit hot summer and cold winter seasons.
> > 
> > However when I added purchased hot water and set a heating coil 
in the 
> > air system into the original model, the data of Heating: 
Purchased 
> > heating (J) was so small.
> > 
> > Is there any problem for my setting? How can I fix this problem 
to 
> > increase the heating load?
> > 
> > And now the cooling:Purchased cooling results also not 
satisfactory 
> > (says 1XXX watt hourly, but I may need 3XXX watt hourly), if I 
want to 
> > make the simulation results closer to my measurement data, which 
> > parameter(s) could I change to achieve more significant results?
> > 
> > 
> > 
> > The primary EnergyPlus web site is found at:
> > http://www.energyplus.gov
> > 
> > The group web site is:
> > http://groups.yahoo.com/group/EnergyPlus_Support/
> > 
> > Attachments are not allowed -- please post any files to the 
appropriate folder
> > in the Files area of the Support Web Site.
> > 
> > EnergyPlus Documentation is searchable.  Open EPlusMainMenu.pdf 
under the
> > Documentation link and press the "search" button.
> > 
> > Yahoo! Groups Links
> > 
> > 
> > 
> > 
> > 
> 
> 
> ========================================================
> Michael J. Witte, GARD Analytics, Inc.
> EnergyPlus Testing and Support      
> EnergyPlus-Support@...
>




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