It can indeed get quite confusing.
For the HX and Fan, this is actually exactly the same way you would do with a regular AirLoopHVAC: the HX and relief fan are going to be specified in relation to the AirLoopHVAC:OutdoorAirSystem. The weird thing is that your DOAS Coils and Fans are ALSO going to be specified in relation to the AirLoopHVAC:OutdoorAirSystem.
Another thing is that you won't have an OutdoorAir:Mixer (which makes it clearer which node is which node...).
Anyways, after using the right node connections, I can get a simulation to run properly (with some warnings, but I'm not trying to do something production ready here). Node connections is really the tricky bit, but OpenStudio SDK can help you do that, which is what I've done.
The other thing is is the order of the equipment on AirLoopHVAC:OutdoorAirSystem:EquipmentList matters a lot (the warning says so!). I chose to put the supply Fan first in line, and the relief last in line.
I have saved a working IDF file for you in this gist: https://gist.github.com/jmarrec/3dc37... . Search for "DOAS" (around line 1450), as I have been careful to name things properly.
The TL;DR is this:
AirLoopHVAC:DedicatedOutdoorAirSystem,
AirLoopDOAS, !- Name
AirLoopDOAS OA Sys, !- AirLoopHVAC:OutdoorAirSystem Name
Always On Discrete, !- Availability Schedule Name
AirLoopDOAS Mixer, !- AirLoopHVAC:Mixer Name
AirLoopDOAS Splitter, !- AirLoopHVAC:Splitter Name
4.5, !- Preheat Design Temperature {C}
0.004, !- Preheat Design Humidity Ratio {kgWater/kgDryAir}
17.5, !- Precool Design Temperature {C}
0.012, !- Precool Design Humidity Ratio {kgWater/kgDryAir}
2, !- Number of AirLoopHVAC
LOOP1, !- AirLoopHVAC Name 1
LOOP2; !- AirLoopHVAC Name 2
AirLoopHVAC:OutdoorAirSystem,
AirLoopDOAS OA Sys, !- Name
, !- Controller List Name
AirLoopDOAS OA Sys Equipment List; !- Outdoor Air Equipment List Name
OutdoorAir:NodeList,
AirLoopDOAS OA Sys OA Inlet Node; !- Node or NodeList Name 1
! ORDER MATTERS HERE
AirLoopHVAC:OutdoorAirSystem:EquipmentList,
AirLoopDOAS OA Sys Equipment List, !- Name
Fan:SystemModel, !- Component Object Type 1
AirLoopDOAS Supply Fan, !- Component Name 1
HeatExchanger:AirToAir:SensibleAndLatent, !- Component Object Type 2
AirLoopDOAS HX, !- Component Name 2
CoilSystem:Heating:DX, !- Component Object Type 3
AirLoopDOAS HC CoilSystem, !- Component Name 3
CoilSystem:Cooling:DX, !- Component Object Type 4
AirLoopDOAS CC CoilSystem, !- Component Name 4
Fan:SystemModel, !- Component Object Type 5
AirLoopDOAS Relief Fan; !- Component Name 5
HeatExchanger:AirToAir:SensibleAndLatent,
AirLoopDOAS HX, !- Name
[...]
AirLoopDOAS OA Sys OA Inlet Node, !- Supply Air Inlet Node Name
AirLoopDOAS OA Sys HX Outlet Node, !- Supply Air Outlet Node Name
AirLoopDOAS OA Sys Return Air Node, !- Exhaust Air Inlet Node Name
AirLoopDOAS OA Sys HX Relief Outlet Air Node, !- Exhaust Air Outlet Node Name
[...]
Yes; !- Economizer Lockout
CoilSystem:Heating:DX,
AirLoopDOAS HC CoilSystem, !- Name
Always On Discrete, !- Availability Schedule Name
Coil:Heating:DX:SingleSpeed, !- Heating Coil Object Type
AirLoopDOAS HC; !- Heating Coil Name
Coil:Heating:DX:SingleSpeed,
AirLoopDOAS HC, !- Name
[...]
AirLoopDOAS OA Sys HX Outlet Node, !- Air Inlet Node Name
AirLoopDOAS HC Outlet to CC Inlet Node, !- Air Outlet Node Name
[...]
2000; !- Resistive Defrost Heater Capacity {W}
CoilSystem:Cooling:DX,
AirLoopDOAS CC ...
(more)
