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[EnergyPlus_Support] PTHP serving two Zones

All,

Already have a model which works with two PTHPs serving two Zones,
gives me system loads, simulation results and all - appears good!

Now trying to model the effect of a single PTHP serving the 2 Zones. 
I have one zone with a very peaky solar load and another with a very
stable equipment load and I want to demonstrate the temperature
fluctuations in the space not being monitored by the PTHP controls.

Was unable to find a way to tell a PTHP to serve a pair of zones in
compact.idf representation.  So am trying to use the expidf created
from the two zone two PTHP model.  

I have seen the 5ZoneAutoDXVAV.idf example and being new to E+ it
makes the mind boggle!  From my two PTHP two zone model the PTHP was
connected directly to the Supply and Return Nodes of the Zones so I
though it cant be that hard and decided to jump in, deleted on PTHP
dropped in a ZONE SPLITTER and ZONE MIXER and working from there.

I believe a lot of the complexity in 5ZoneAutoDXVAV.idf comes from the
autosizing.  I know what the cooling capacity of my PTHP should be, so
I dont think I need the complexity of autosizing.

For the Air Loop I have gotten as far as, PTHP discharging into a ZONE
SUPPLY AIR PATH with contains a single ZONE SPLITTER, feeding the
inlet nodes of two CONTROLLED ZONE EQUIP CONFIGURATION, each ZONE
EQUIPMENT LIST has a single DIRECT AIR distribution equipment.

CONTROLLED ZONE EQUIP CONFIGURATION return air nodes are connected to
a ZONE RETURN AIR PATH containing a single ZONE MIXER which directs
air back to the Air Inlet Node of the PTHP.

An excerpt of my .idf looks like;

PACKAGEDTERMINAL:HEATPUMP:AIRTOAIR,

  1 PTHP,
  On,
  1 PTHP Supply,
  1 PTHP Return,
  1 PTHP Outside Air Inlet,
  1 PTHP Relief Air Outlet,
  1 PTHP OA Mixing Box,
<snip>

ZONE SUPPLY AIR PATH,

  Zone Supply Air Path,
  1 PTHP Supply,
  ZONE SPLITTER,
  Zone Supply Air Splitter;


ZONE SPLITTER,

  Zone Supply Air Splitter,
  1 PTHP Supply,
  1 Zone Air Supply,
  2 Zone Air Supply;

When running I am getting;

** Severe  ** Node Connection Error, Node="1 PTHP SUPPLY", Inlet node
did not find an appropriate matching "outlet" node.
**   ~~~   ** If this is an outside air inlet node, it must be listed
in an OUTSIDE AIR NODE or OUTSIDE AIR INLET NODE LIST object.
**   ~~~   ** Reference Object=ZONE SUPPLY AIR PATH, Name=ZONE SUPPLY
AIR PATH
** Severe  ** Node Connection Error, Node="1 PTHP SUPPLY", Inlet node
did not find an appropriate matching "outlet" node.
**   ~~~   ** If this is an outside air inlet node, it must be listed
in an OUTSIDE AIR NODE or OUTSIDE AIR INLET NODE LIST object.
**   ~~~   ** Reference Object=ZONE SPLITTER, Name=ZONE SUPPLY AIR
SPLITTER

To my read the Node connectivity is right, I have tried switching 1
PTHP Supply and 1 PTHP Return in the
PACKAGEDTERMINAL:HEATPUMP:AIRTOAIR object to no effect.

Is this E+'s way of telling me that it does not know what the division
of airflow should be?  

Can I use a PTHP to serve multiple zones?

How should I be defining (without autosizing) how much air goes into
each zone?

Is there a more simplistic example than 5ZoneAutoDXVAV.idf to consult?

Regards,

Mark Carey


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