RE: [EnergyPlus_Support] Re: Multiple Zones for Single Heat Pump

The following paper described the building which has 4 modular heatpumps with VAV VSD fans, and 220 VAV diffusers:

Air conditioning for the Dulux ORICA new building in Melbourne, Australia

First International Conference of Building Energy and Environment, COBEE08, Dalian China, July 13 -17, 2008 Topic 8.Advanced or innovative HVAC&R systems and system components

Koon Beng Ooi*, Azhaili Baharum^{Faculty of Engineering, University Malaysia Sarawak, Malaysia.}

*Corresponding email: ooi_kb3@xxxxxxxxxxx

Mr. Ooi was my former student and we, in 2008, used EPlus to find the real set point not met problem in this building.
Dr. Li

To: energyplus_support@xxxxxxxxxxxxxxx
From: yli006@xxxxxxxxxxx
Date: Tue, 24 Jan 2012 19:37:43 -0500
Subject: RE: [EnergyPlus_Support] Re: Multiple Zones for Single Heat Pump

Why don't you run the 5zone VAV template example and turn off the reheat coil.

Change the minimum zone VAV damper position to 0.01. Reference node for cooling to 18°C or higher instead of 12.7°C, but a few degrees lower than the zone thermostat set point or cooling.

When you get the set point not met warnings, increase the sizing multiplier on the template.

If the above is satisfactorily, apply it to your system.

The set point manager for the reference node, makes the duct temperature constant, and thus releases the theremostat back to your master zone.

12.7°C is too cold for the zone without reheat.

Set point not met is when the VAV demper is fully open and the zone is still above the set point temperature. Increase the sizing multiplier increases the air volume at this point. For a large internal heat load variation, you may need to double the sizing.

The heat pump can be air or water cooled depends on the maximum cooling load demand of the system. If it is water cooled, the unit must not be exposed and un-protected in Winter.

Dr. Li

To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: luke.dorna@xxxxxxxxx
Date: Tue, 24 Jan 2012 18:50:40 +0000
Subject: [EnergyPlus_Support] Re: Multiple Zones for Single Heat Pump

The problem I find thus far is this:

AirLoopHVAC:UnitaryHeatPump:WaterToAir,
...
zoneA, !- Controlling Zone or Thermostat Location
....

I find that the HP turns off if zoneA is satisfied, even if zoneB which is also being served by the HP, needs additional conditioning. Or the opposite effect, where additional conditioning is pumped into a zone because of the minimum turndown ratio.

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, YuanLu Li <yli006@...> wrote:
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> What you have descibed is a standard HP with multiple fan coil units. Fan speed may be simply 1,2,3 selection. VAV diffusers are also available in EPlus . (variable damper cantrolled by zone thermostat.) May be it is not in the templete series, but has been in use for a long time.. Dr. Li
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> From: luke.dorna@...
> Date: Tue, 24 Jan 2012 18:08:22 +0000
> Subject: [EnergyPlus_Support] Re: Multiple Zones for Single Heat Pump
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> The system actually uses heat pumps with variable volume fans to serve multiple zones. However, e plus only allows for on/off fans in the HP objects I'm using. I discovered that throwing vav boxes on the supply inlets to rooms allows the fan speed to modulate. Nifty work around.
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> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Karen Walkerman <kwalkerman@> wrote:
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> >
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> > Any reason you're not using ZoneHVAC:WaterToAirHeatPump? Put one in each
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> > zone...
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> > Also, how does the building operate in reality? Does it really have heat
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> > pumps serving VAV boxes?
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> >
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> > --
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> > Karen
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> > On Mon, Jan 23, 2012 at 4:20 PM, luke_dorna <luke.dorna@> wrote:
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> > > **
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> > >
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> > > I'm doing exactly that, using a single heat pump and distributing the
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> > > capacity.
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> > >
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> > > I was hoping there was a work around that would allow me to treat these as
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> > > per a standard AHU with VAV outlets, but it doesn't appear that Energy+ is
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> > > going to cooperate.
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> > >
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> > > Thanks,
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> > >
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> > >
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> > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Jim Dirkes" <jim@> wrote:
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> > > >
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> > > > Dear Luke,
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> > > >
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> > > > Thinking about this, it is common for a WSHP to serve more than one room,
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> > > > but uncommon for there to be more than one thermostat (i.e. multi-zone).
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> > > > These devices are pretty much a one zone component.
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> > > >
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> > > > That said, you can only do what the software allows or for which there
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> > > is a
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> > > > reasonable work-around. When you think of it, a reasonably designed
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> > > system
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> > > > will normally include zones with similar occupancy, schedule, set points,
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> > > > etc. If that's true, just assign one heat pump per zone, using the same
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> > > COP,
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> > > > fan performance, etc. as for a larger multi-zone heat pump. If it's not
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> > > > true, one WSHP per zone is still the best available solution, since E+
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> > > does
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> > > > not have a multi-zone WSHP object (as you already note).
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> > > >
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> > > >
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> > > >
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> > > > The Building Performance Team
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> > > > James V. Dirkes II, P.E., BEMP , LEED AP
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> > > > 1631 Acacia Drive NW
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> > > > Grand Rapids, MI 49504
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> > > > 616 450 8653
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> > > >
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> > > >
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> > > >
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> > > > From: EnergyPlus_Support@xxxxxxxxxxxxxxx
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> > > > [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of luke_dorna
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> > > > Sent: Monday, January 23, 2012 3:05 PM
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> > > > To: EnergyPlus_Support@xxxxxxxxxxxxxxx
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> > > > Subject: [EnergyPlus_Support] Multiple Zones for Single Heat Pump
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> > > >
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> > > >
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> > > >
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> > > >
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> > > >
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> > > > I am currently using the the AirLoopHVAC:UnitaryHeatPump:WaterToAir
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> > > object
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> > > > to model distributed heat pumps throughout a building. Unfortunately, the
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> > > > object only allows for a single controlling thermostat, but the design
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> > > calls
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> > > > for heat pumps that serve multiple rooms.
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> > > >
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> > > > Has anyone encountered/found a way around this?
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> > > >
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> > > > I've tried attaching reheat VAVs to the different zones but didn't have
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> > > much
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> > > > luck.
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> > > >
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> > > > Thanks,
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> > > >
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> > > > Luke
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> > > >
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> > >
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> > >
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