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,
"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@xxxxxxxxxxxxxxx]
On Behalf Of jeannieboef
> Sent: Monday, August 30, 2010 9:00 AM
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> 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> , 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@xxxxxxxxxxxxxxx
> <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>
> > > 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> ,
"jeannieboef"
> > > <jeannieboef@> wrote:
> > > >
> > > > anybody have an idea as to how to do this?
> > > >
> > >
> > >
> > >
> >
>
__._,_.___
Primary EnergyPlus support is found at:
http://energyplus.helpserve.com or send a message to energyplus-support@xxxxxxxx
The primary EnergyPlus web site is found at:
http://www.energyplus.gov
The group web site is:
http://groups.yahoo.com/group/EnergyPlus_Support/
Attachments are currently allowed but be mindful that not everyone has a high speed connection. Limit attachments to small files.
EnergyPlus Documentation is searchable. Open EPlusMainMenu.pdf under the Documentation link and press the "search" button.
Change settings via the Web (Yahoo! ID required)
Change settings via email: Switch delivery to Daily Digest | Switch to Fully Featured
Visit Your Group | Yahoo! Groups Terms of Use | Unsubscribe
__,_._,___