[EnergyPlus_Support] Re: PSZ-AC w/district heating? AirLoopHVAC:Unitary:Furnace:HeatCool only has gas

["Jean marais" <jeannieboef@xxxxxxxxx>]

If you have one AHU per zone, it doesn't matter where the heating coil is...at the exit of the VAV is fine, but beware that the reheating air supply setpoint for the reheater during the cooling season is the ZoneHeatingSetpoint, meaning you'll have to seasonally or otherwise, deactivate reheater availability when cooling is required to meet the ASHRAE cooling air supply temperature requirement (ZoneCoolingSetpoint-11degC). This may effect the HoursLoadsNotMet. Better control is possible if the coil is in the Supplyside of the AirLoop.

I would love to find a schematic of all the system types...these always seem open to interpretation.

I've just loaded up the latest BETA for DB and the system 3, no longer has the reheater in the zone. Personally, I prefer to always use the latest beta and keep an eye on the bug fixes to know which bugs a particular version that I used had to check if my results are trust worthy.

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "FrancescoP" <direzionecontraria@...> wrote:
>
> Thank you, Jean.
> Would you avoid to create one AHU per zone because it is uncomfortable and time consuming for the energy modeler or because of some other reason?
> In the version 3.1.0.034 beta of DesignBuilder system 3 PSZ-AC is modeled with local reheat coil within the zones. Is it correct? For system 3 PSZ-AC is the local reheat coil mandatory or an "optional"? 
> Generally speaking, where could I find schematic representations of the 8 systems of annex G of ASHRAE?
> With Regards
> 
> 
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Jean marais" <jeannieboef@> wrote:
> >
> > It is like you say. I've done it for a 2300m2 object exactly like you described. At the time I was still on the learning curve. The most difficalties I had was setting up the setpointmanagers for the ODAmixer, UnitaryHeatCool utilizing the dxcoil and the fan mode control whilst setting furnace heating coil availibility to zero, and then inserting a water coil connected to a district plant. 
> > 
> > At the time I chose to do 1 AHU per zone (because of the packaged single zone AHU requirement) which I would probably not do again if I can avoid it, so double check the language (I had 28 zones and the LEED reveiw seemed okay with 28 AHUs). For me each zone was a thermal block. This was for many reasons including that I was using the same model for a detailed natural ventilation model and daylighting model. If I had to do it again, I would seperate these three simulations.
> > 
> > Try and lump the zones as close as possible to the 5 zone model.
> > 
> > Anyone else? Do we really need to connect the PSZ-AC to just one zone, or can we hookup more?  
> > 
> > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "FrancescoP" <direzionecontraria@> wrote:
> > >
> > > I have to model a nonresidential building having surface less than 2300m^2. It is connected to a district heating system and I am using Option 1 (streamlined path) of the document "Treatment of District or Campus Thermal Energy in LEED" . Because of Table 2 and Table 3 of "Treatment of District or Campus Thermal Energy in LEED", I think that in such a situation the heat coils shall be heated by a hot water loop in which heat is provided by a DistrictHeating object. Do you agree?
> > > I guess that I have to consider the purchased heat, not the primary energy, both for the model of the proposed building and for the baseline model, therefore efficiencies shall not be considered for heating.
> > > In order to meet setpoint temperatures and to avoid energy waste, how should be grouped the zones? I mean, is connecting every AHU to a single zone the best solution?
> > > Regards
> > > Francesco Passerini
> > > 
> > > 
> > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "James V Dirkes II, PE" <jvd2pe@> wrote:
> > > >
> > > > Dear Jeannie,
> > > > 
> > > >  
> > > > 
> > > > Focusing my thoughts..
> > > > 
> > > > .         Normally a System 3 serves a single thermal zone, so the zone and
> > > > system capacities are identical
> > > > 
> > > > .         If your system capacity is < 19kW (per E+, not the actual
> > > > equipment!), you'll fall in the smallest ASHRAE 90.1 capacity range, so the
> > > > efficiencies will be as shown below
> > > > 
> > > > 
> > > > 
> > > > .         As you can see, I have the IP version of the Standard, however
> > > > your 3.18 SCOP value does not quite line up with these values
> > > > 
> > > > .         In other regards, I think that you are "bang on".  Keep in mind
> > > > that the baseline system is fictitious and has very little to do with the
> > > > real system.  You are clearly (for System 3 and this 19kW system) a "single
> > > > package", "all" heating.  Use the 9.7 or 13.0 EER depending on whether your
> > > > project is filing as built before or after 1/23/06.
> > > > 
> > > >  
> > > > 
> > > > I hope that helps!
> > > > 
> > > >  
> > > > 
> > > > 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 jeannieboef
> > > > Sent: Monday, August 30, 2010 10:12 AM
> > > > To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> > > > Subject: [EnergyPlus_Support] Re: PSZ-AC w/district heating?
> > > > AirLoopHVAC:Unitary:Furnace:HeatCool only has gas or
> > > > 
> > > >  
> > > > 
> > > >   
> > > > 
> > > > In my case you're bang on. very small LEED project, purchased heat.
> > > > LEED's brought out some new guidlines which divert (on purpose) from ASHRAE
> > > > on some small points. I referenced the document earlier. gas is no longer an
> > > > option in my case, hence the whole water loop coil effort. The simulation I
> > > > set up seems to be running and I'll check it tomorrow for the outputs, but I
> > > > still don't know exactly how to match up the system no 3 with the min. eff
> > > > tables in chapter 6 of the standard. That's why I put down my best guess for
> > > > your opinion on which tables apply to PSZ-AC w/district heating equipment.
> > > > 
> > > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx
> > > > <mailto:EnergyPlus_Support%40yahoogroups.com> , "James V Dirkes II, PE"
> > > > <jvd2pe@> wrote:
> > > > >
> > > > > Dear Jeannie and Vinay,
> > > > > 
> > > > > 
> > > > > 
> > > > > . I have not followed this thread of conversation from the
> > > > > beginning, and cannot give you too much time to look it up. but I'll try.
> > > > > 
> > > > > . Assuming that you are involved with a LEED project, your baseline
> > > > > HVAC is PZ-AC only if the building 
> > > > > 
> > > > > o has 3 floors or less
> > > > > 
> > > > > o is also less than 25,000 sq.ft.
> > > > > 
> > > > > o and the proposed system is fossil-fueled or purchased heat
> > > > > 
> > > > > . That means your baseline system should be defined with a DX
> > > > > cooling coil and fossil-fueled heating coil. I think that I would use a
> > > > gas
> > > > > coil for the baseline; it's simpler to create (no water loop).
> > > > > 
> > > > > . I use component efficiencies appropriate for the modeled system
> > > > > (the entire air or water loop, not individual zones). Baseline systems
> > > > > require autosizing per ASHRAE 90.1, so you will have to get the model
> > > > > running, then check the reports to see what capacity E+ has determined,
> > > > then
> > > > > adjust your input efficiencies as needed to match the 90.1 requirements.
> > > > > 
> > > > > . The proposed system will be exactly as designed by you (or
> > > > > whomever is the designer), including components and efficiencies.
> > > > > 
> > > > > 
> > > > > 
> > > > > 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%40yahoogroups.com> 
> > > > > [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx
> > > > <mailto:EnergyPlus_Support%40yahoogroups.com> ] On Behalf Of jeannieboef
> > > > > Sent: Monday, August 30, 2010 9:00 AM
> > > > > To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> > > > <mailto:EnergyPlus_Support%40yahoogroups.com> 
> > > > > Subject: [EnergyPlus_Support] Re: PSZ-AC w/district heating?
> > > > > AirLoopHVAC:Unitary:Furnace:HeatCool only has gas or
> > > > > 
> > > > > 
> > > > > 
> > > > > 
> > > > > 
> > > > > Mr. Dirkes,
> > > > > 
> > > > > I'm also having trouble pinning down the required efficiencies.
> > > > > 
> > > > > I'm guessing the following at the moment:
> > > > > System Type: Packaged rooftop air conditioner
> > > > > Fan Control: Constant Volume
> > > > > Cooling Type: Direct Expansion (DX)
> > > > > Cooling Capacity: (zone dependant, ranging from 5.2 kW to 0.1 kW)
> > > > > 
> > > > > Min Efficiency Requirements as per Table 6.8.1A Air Conditioners,
> > > > > Equipment Type: Air Conditioners, air cooled (as DX coils are air cooled),
> > > > > Size Category: <19 kW (rated cooling capacity?),
> > > > > Heating Section Type "All"
> > > > > Subcategory or Rating Condition: Single Package
> > > > > Minimum Efficiency (cooling?): 3.18 SCOP (as of 1/23/2006)
> > > > > 
> > > > > Heating Type: Normally Fossil fuel furnace, but as per Treatment of
> > > > District
> > > > > or Campus Thermal Energy in LEED V2 and LEED 2009 - Design & Construction,
> > > > > August 13 2010 - Purchased District Heating
> > > > > 
> > > > > Heating Capacity: (zone dependant, ranging from 4.4 kW to 0.1 kW)
> > > > > 
> > > > > What will the heating coil efficiencies be? I see options for implementing
> > > > > cooling coil efficiencies (using the modifier curves as per DOE-2.1E) and
> > > > > part load functions, but not for a hot water coil. Is there any
> > > > requirement
> > > > > for how much heat must be transfered from the coil to the air?
> > > > > 
> > > > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx
> > > > <mailto:EnergyPlus_Support%40yahoogroups.com> 
> > > > > <mailto:EnergyPlus_Support%40yahoogroups.com> , Vinay Devanathan
> > > > > <vinay.devanathan@> wrote:
> > > > > >
> > > > > > Mr. Dirkes,
> > > > > > 
> > > > > > Do we have to use only coil:hot water or can we also use coil:gas?
> > > > > > 
> > > > > > Thank you.
> > > > > > 
> > > > > > On Aug 30, 2010, at 6:59 AM, "James V Dirkes II, PE" <jvd2pe@> 
> > > > > > wrote:
> > > > > > 
> > > > > > > Dear Jeannie,
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > Just construct an Air Loop which has a fan, (hot water) heating coil 
> > > > > > > and DX cooling.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > There is nothing magical about the Furnace:HeatCool object; it just 
> > > > > > > has a cycling (on:off) fan, a heating coil and a cooling coil.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > 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%40yahoogroups.com> 
> > > > > <mailto:EnergyPlus_Support%40yahoogroups.com> 
> > > > > > > [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx
> > > > <mailto:EnergyPlus_Support%40yahoogroups.com> 
> > > > > <mailto:EnergyPlus_Support%40yahoogroups.com> ] On Behalf Of jeannieboef
> > > > > > > Sent: Monday, August 30, 2010 4:40 AM
> > > > > > > To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> > > > <mailto:EnergyPlus_Support%40yahoogroups.com> 
> > > > > <mailto:EnergyPlus_Support%40yahoogroups.com> 
> > > > > > > Subject: [EnergyPlus_Support] Re: PSZ-AC w/district heating? 
> > > > > > > AirLoopHVAC:Unitary:Furnace:HeatCool only has gas or
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > Is everyone on holiday?
> > > > > > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx
> > > > <mailto:EnergyPlus_Support%40yahoogroups.com> 
> > > > > <mailto:EnergyPlus_Support%40yahoogroups.com> , "jeannieboef" 
> > > > > > > <jeannieboef@> wrote:
> > > > > > > >
> > > > > > > > anybody have an idea as to how to do this?
> > > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>




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