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[EnergyPlus_Support] Re: Modeling VRV system
I really appreciate your help, James. Thank you.
Have you ever submitted this type of VRF-approximate model for LEED certification?
Has anybody out there submitted any other these "almost-VRF" for LEED?
I would though, if you don't mind and have some free time for it, if you could further describe your method.
Thank you again.
Have a great day!
Francisco
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "James V Dirkes II, PE" <jim@...> wrote:
>
> Dear Francisco,
>
>
>
> I do not think that you can properly simulate VRF with individual zone DX
> systems.
>
>
>
> A VRF system essentially responds to the total system load. If, for
> example, 5 zones are in heating mode, and 6 are in cooling mode, you might
> have a cooling load that is a small percentage of the total capacity. This
> can be true even if the 6 cooling mode zones are operating at 100% of their
> capacity. In this situation, the true part load of the system may be only
> 9% (as an example).
>
>
>
> I hope that is clear (I don't have time now for more details)!
>
>
>
> For that reason, I think a better approach is:
>
> · WSHP in each zone with COP = 1000 (yes, one thousand so that there
> is essentially no compressor heat added at the zone level)
>
> · WSHPs served by a chiller (COP= 1000) and boiler (efficiency =
> 1.0)
>
> · Create a custom meter for the chiller and boiler energy
>
> · Via post-processing (e.g., Excel spreadsheet), calculate the net
> heating / cooling load and apply a part load factor appropriate for the VRF
> manufacturer
>
> · Calculate a new total for electric usage based on the new
> calculated VRF electricity use.
>
>
>
> The Building Performance Team
> James V. Dirkes II, P.E., LEED AP
> 1631 Acacia Drive NW
> Grand Rapids, MI 49504
> 616 450 8653
>
>
>
> From: EnergyPlus_Support@xxxxxxxxxxxxxxx
> [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of fm1n0
> Sent: Thursday, February 10, 2011 7:28 AM
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Subject: [EnergyPlus_Support] Re: Modelling VRV system
>
>
>
>
>
> Hi.
> I'm attempting the approximate-VRF method mentioned below.
> COIL:COOL/HEAT:DX:MULTISPEED
> 1. Should the rated conditions be the same for all speeds?
> 2. Curves: are they defined by E+ or user-defined?
>
> InputOutput p.1477
> "rating point (the air entering the cooling coil at 26.7°C drybulb/19.4°C
> wetbulb and air entering the outdoor condenser coil at 35°C drybulb/23.9°C
> wetbulb)"
> InputOutput p.1514
> "the multispeed coil object is described by specifying the performance at
> different operating speeds at rated conditions"
>
> thanks
>
> Francisco
>
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx
> <mailto:EnergyPlus_Support%40yahoogroups.com> , "alberto" <ahneto@>
> wrote:
> >
> > Dear Mark,
> >
> > The four step variation I mentioned is related to the menu
> COIL:COOLING:DX:MULTISPEED where we can set 04 different speeds where the
> model of such coil can be simulated. For each speed, you can provide all the
> parameters that can represent the coil but it is different from a VRF
> because the system works in a continuous variation of these parameters but I
> think it is the closest model EnergyPlus have at the moment.
> >
> > Alberto
> >
> > ----- Original Message -----
> > From: Zoeteman, Mark R.
> > To: ahneto@
> > Cc: EnergyPlus_Support@xxxxxxxxxxxxxxx
> <mailto:EnergyPlus_Support%40yahoogroups.com>
> > Sent: Monday, May 24, 2010 11:40 AM
> > Subject: [EnergyPlus_Support] Modelling VRV system
> >
> >
> >
> >
> >
> > Alberto,
> >
> > Is following page 14 from "Tips and Tricks for Using EnergyPlus" what you
> are referring to model VRV system? I don't see reference to a four stepped
> variation you referred to in your response to Felipe Agustin.
> >
> > Mark Zoeteman, FTC&H
> >
>
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