[EnergyPlus_Support] Re: Chilled Water at 2 different Temperatures

["Jean marais" <jeannieboef@xxxxxxxxx>]

Thanks James. I've made the additional PlantLoop and that's working great.

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Jim Dirkes" <jim@...> wrote:
>
> Dear Jean,
> 
>  
> 
> I think there was a post several months ago regarding this same issue.  I am
> pretty sure that you cannot model two different setpoint temperatures in the
> same chilled water loop with E+.
> 
> Considerations for a  workaround:
> 
> .         The Chilled beam object does not object to colder water, nor does
> the water flow rate change as long as you maintain the proper delta T . so
> energy should remain the same
> 
> o   You may want to revise the object parameters to make sure the beam
> performs the same as with warmer water
> 
> o   I know someone was asking recently in this forum (or Bldg-Sim) about
> modeling the dewpoint shutoff feature of chilled beams.  I did not follow
> that closely because I felt that most chilled beams systems (in the USA)
> will use a DOAS that controls humidity, making the dewpoint control less
> active.  Nonetheless, that may be a concern for you.  My
> not-thinking-about-it -very-long workaround would be to monitor room
> dewpoint and raise the room setpoint during those periods.
> 
> .         You CAN use two different chilled water loops and may want to do
> so for your radiant loop.
> 
> o   Ideally, you'd like to take advantage of what is probably a higher
> return water temp from the radiant loop for chiller efficiency.  With two
> loops, this becomes more difficult, but I think you could make an
> approximation.
> 
>  
> 
>  
> 
>  
> 
> The Building Performance Team
> James V. Dirkes II, P.E., BEMP , LEED AP
> 1631 Acacia Drive NW
> Grand Rapids, MI 49504
> 616 450 8653
> 
>  
> 
> From: EnergyPlus_Support@xxxxxxxxxxxxxxx
> [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Jean marais
> Sent: Friday, July 22, 2011 7:31 AM
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Subject: [EnergyPlus_Support] Re: Chilled Water at 2 different Temperatures
> 
>  
> 
>   
> 
> Any help on this?
> 
> How do I set up my loops to deliver 6 degC CW to my AHU, but 18 degC CW to
> my radiant system. One can only have one PlantLoop, right?
> 
> If I give my AHU the 18 degC water, I don't get the dehumidification.
> If I give my ceiling 6 degC water, I get condensation.
>




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