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Re: [EnergyPlus_Support] model VRF system
You must ask the eQuest support group that question. I have never used
eQuest.
mohammd al masri wrote:
>
>
> thanx alot Dear
> But actually iam looking for using VRF system by eQuest simulation program
> iam totally understand your replay, but eQuest have alot of systems
> and a lot of parameters that must be specified.
> Do you have any idea how to use it in equest? i have to be sure.
> Regards
>
> ------------------------------------------------------------------------
> *From:* Richard Raustad <RRaustad@xxxxxxxxxxxx>
> *To:* EnergyPlus_Support@xxxxxxxxxxxxxxx
> *Sent:* Wednesday, June 17, 2009 3:52:41 PM
> *Subject:* Re: [EnergyPlus_Support] model VRF system
>
> I think the closest you could get on the cooling side would be to use an
> AirloopHVAC: UnitaryCoolOnly with AirTerminal: SingleDuct:
> VAV:NoReheat air
> distribution units. The power side of the VRF would have to be modeled
> using a squared curve on PLR where Power is proportional to the square
> of speed (or PLR). However, with this configuration the fan power will
> be low since VRF systems typically use constant volume fans. You can
> modify the fan power in a spreadsheet after the simulation is complete.
> Sorry if the jpg doesn't come through but it just shows the squared
> power law of power vs speed..
>
> For heating it is much harder. Using the
> AirloopHVAC: UnitaryHeatPump: AirToAir with
> AirTerminal: SingleDuct: Uncontrolled will model both cooling and
> heating,
> however, the compressor control is limited to a single zone. If the zone
> loads are balanced (flow through air distribution units are balanced
> based on load) this will be a fair approximation, at least with what is
> available in EnergyPlus. You could still use the squared curve for power
> in this object.
>
> So there is no simple answer, you would have to pick a system and review
> the results to see how close you are to manufacturers performance data.
> Then modify the input to more closely model the system using different
> configurations. There are many EnergyPlus users that would be interested
> in your findings.
>
> VRFPower.jpg
>
> mohammd al masri wrote:
> >
> >
> > Dear all,
> > I have a VRF (variable refrigerant flow) system , how I can model it ?
> > can I use something closeor similar to that system , some mechanical
> > engineers tolds me to select cooling tower system .
> >
> > Any help,
> > Thanx
> >
> >
>
> --
> Richard A. Raustad
> Senior Research Engineer
> Florida Solar Energy Center
> University of Central Florida
> 1679 Clearlake Road
> Cocoa, FL 32922-5703
> Phone: (321) 638-1454
> Fax: (321) 638-1439 or 1010
> Visit our web site at: http://www.fsec. ucf.edu <http://www.fsec.ucf.edu/>
>
> UCF - From Promise to Prominence: Celebrating 40 Years
>
>
>
--
Richard A. Raustad
Senior Research Engineer
Florida Solar Energy Center
University of Central Florida
1679 Clearlake Road
Cocoa, FL 32922-5703
Phone: (321) 638-1454
Fax: (321) 638-1439 or 1010
Visit our web site at: http://www.fsec.ucf.edu
UCF - From Promise to Prominence: Celebrating 40 Years
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