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[EnergyPlus_Support] Re: Two AHUs for a zone
Hello James,
the problem regards the model of the proposed building. There is an AHU that is connected to a lot of zones. That AHU doesn't have any cooling system. In fact, the proposed AHU has a heat recovery system, a preheat coil, a humidifier, a heating coil, and two fans (constant velocity).
The baseline system has to be System 4 ? PSZ-HP. To meet the setpoint temperatures I have to model a PSZ-HP system for every zone.
About the model of the proposed building table G3.1 point 10.d states: "Where no cooling system exists or no cooling system has been specified, the cooling system shall be identical to the system modeled in the baseline building design". Therefore I have to model a System 4 ? PSZ-HP as cooling system also for the model relative to the proposed building. I thought that I could connect every zone to the real AHU as heating system and to a virtual PSZ-HP system in order to have cooling, but if I cannot model two air loops serving a single zone I have to look for another solution. I don't know if adding a virtual DX cooling in the proposed AHU is a good solution, because the proposed AHU is connected to a lot of zones, while every PSZ-HP system of the baseline is connected only to a single zone. But does a better solution exist?
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Jim Dirkes <jim@...> wrote:
>
> Dear Francesco,
>
> * I do not think it is possible to model two air loops serving a single zone
>
> * You can model one Air Loop plus one type of Zone equipment (e.g. PTAC)
>
> * I cannot think what requirement of Appendix G would require such a system
>
> James V Dirkes II, PE, BEMP, LEED AP
> www.buildingperformanceteam.com<http://www.buildingperformanceteam.com/>
> Energy Analysis, Commissioning & Training Services
> 1631 Acacia Drive, Grand Rapids, MI 49504 USA
> 616 450 8653
>
> From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of FrancescoP
> Sent: Tuesday, October 23, 2012 10:46 AM
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Subject: [EnergyPlus_Support] Two AHUs for a zone
>
>
>
> I would like to model a zone as connected to two different AHUs, one AHU with heating coil and the other one with cooling coil (it isn't a real HVAC system; this model is for ANNEX G of ASHRAE 90.1-2007). Is it possible? How should I specify the ZoneHVAC:Equipmentconnections? Should I specify the two inlet nodes in the same nodelist? Should the "zone retuen air node name" be the same for the two systems?
> Do you know if there is an example file with such a situation, please?
> With Regards
>
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